release: notes list calls as a known issue, and new releases start as pre-releases

Updated Liberapay username to remove URL.

.github/FUNDING.yml

@@ -0,0 +1,15 @@
+# These are supported funding model platforms
+
+github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: # Replace with a single Tidelift platform-name/package-name e.g., npm/babel
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: Seb3thehacker
+issuehunt: # Replace with a single IssueHunt username
+lfx_crowdfunding: # Replace with a single LFX Crowdfunding project-name e.g., cloud-foundry
+polar: # Replace with a single Polar username
+buy_me_a_coffee: # Replace with a single Buy Me a Coffee username
+thanks_dev: # Replace with a single thanks.dev username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,59 @@
+name: Bug report
+description: Something in Gearslip broke or behaves wrong.
+labels: ["bug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for reporting. Check the [open issues](https://github.com/Seb3thehacker/gearslip/issues) first, in case someone has already reported it.
+
+  - type: input
+    id: car
+    attributes:
+      label: Car
+      description: Make, model, and year.
+      placeholder: 2019 Honda Civic
+    validations:
+      required: true
+
+  - type: dropdown
+    id: head-unit
+    attributes:
+      label: Head unit
+      options:
+        - The one the car came with
+        - A factory unit from another car
+        - An aftermarket unit (Pioneer, Kenwood, Alpine, and so on)
+        - A homemade or open-source unit, such as LIVI
+        - I don't know
+    validations:
+      required: true
+
+  - type: dropdown
+    id: connection
+    attributes:
+      label: Connection
+      options:
+        - USB cable
+        - Wireless dongle
+    validations:
+      required: true
+
+  - type: textarea
+    id: what-happened
+    attributes:
+      label: What happened
+      description: What you did, what you expected, and what happened instead.
+    validations:
+      required: true
+
+  - type: textarea
+    id: log
+    attributes:
+      label: Log
+      description: |
+        On the phone, open Logs from Gearslip's home screen and tap Share log. Drag the file here.
+        The log records your phone, its Android version, the Gearslip version, and why the connection ended.
+      placeholder: Drop the log file here.
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/car_report.yml

@@ -0,0 +1,65 @@
+name: Car report
+description: Tell us whether Gearslip works in your car, so others know before they install.
+labels: ["car report"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Reports from working cars help as much as reports from broken ones.
+
+  - type: input
+    id: car
+    attributes:
+      label: Car
+      description: Make, model, and year.
+      placeholder: 2019 Honda Civic
+    validations:
+      required: true
+
+  - type: dropdown
+    id: head-unit
+    attributes:
+      label: Head unit
+      options:
+        - The one the car came with
+        - A factory unit from another car
+        - An aftermarket unit (Pioneer, Kenwood, Alpine, and so on)
+        - A homemade or open-source unit, such as LIVI
+        - I don't know
+    validations:
+      required: true
+
+  - type: dropdown
+    id: connection
+    attributes:
+      label: Connection
+      options:
+        - USB cable
+        - Wireless dongle
+    validations:
+      required: true
+
+  - type: dropdown
+    id: result
+    attributes:
+      label: Does it work?
+      options:
+        - Yes, everything I tried works
+        - Partly. It connects, but something is wrong
+        - No, it never connects
+    validations:
+      required: true
+
+  - type: textarea
+    id: notes
+    attributes:
+      label: Notes
+      description: What you tried, and anything that didn't work.
+
+  - type: textarea
+    id: log
+    attributes:
+      label: Log
+      description: |
+        Needed if the car doesn't work. On the phone, open Logs from Gearslip's home screen and tap Share log. Drag the file here.
+      placeholder: Drop the log file here.

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1 @@
+blank_issues_enabled: false

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,23 @@
+name: Feature request
+description: Suggest something Gearslip should do.
+labels: ["enhancement"]
+body:
+  - type: textarea
+    id: problem
+    attributes:
+      label: What do you want to do?
+      description: Describe the problem, not the solution. "I can't see my next turn while music plays" helps more than "add a turn widget."
+    validations:
+      required: true
+
+  - type: textarea
+    id: idea
+    attributes:
+      label: How should it work?
+      description: Your idea for a fix, if you have one.
+
+  - type: textarea
+    id: apps
+    attributes:
+      label: Apps involved
+      description: Any apps this touches, such as a map or music app.

.github/dependabot.yml

@@ -0,0 +1,15 @@
+# Weekly pull requests for newer Gradle libraries and GitHub Actions, aimed at experimental,
+# where unreleased code lands. Security fixes come separately, as soon as an alert opens.
+version: 2
+updates:
+  - package-ecosystem: gradle
+    directory: /
+    target-branch: experimental
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 5
+  - package-ecosystem: github-actions
+    directory: /
+    target-branch: experimental
+    schedule:
+      interval: weekly

.github/release-notes.md

@@ -0,0 +1,26 @@
+Gearslip 0.3 goes wireless, takes voice commands, and works with the car's rotary knob.
+
+## New
+- **Wireless Android Auto.** Pair the phone with the car once, and leave the cable at home.
+- **Voice control, on the phone.** Say "navigate to a gas station", "play" a song or artist, or open an app by name. Gearslip turns speech into text itself, so it needs no Google account. "Navigate to" picks the nearest place and stops at the map app's start screen.
+- **The rotary knob.** The car's knob moves between buttons, so cars without a touchscreen work too.
+- **Music over Bluetooth or USB.** Bluetooth plays as the phone normally would. USB has no delay but asks to share audio each drive. Gearslip offers to pair with the car the first time.
+- **Directions on the car.** The car speaks each turn from your map app, and shows the directions on its own display where it can.
+- **Updates in the app.** Gearslip finds new versions and installs them, with an optional beta channel.
+- **Button styles** for the car screen, picked in the intro or the car's settings.
+
+## Fixed
+- More cars play music over USB, including ones that refused Gearslip's audio before.
+- Cars that give no screen size get a sharper picture, up to 1080p, and taps land where you press on cars that crop the edges.
+- A new destination mid-route replaces the old route, and switching map apps ends the old app's route.
+- Tidal's like and shuffle buttons show their real state.
+- MapQuest finds your location.
+
+## Changed
+- The app is half the size: 30 MB instead of 65.
+- On GrapheneOS, Gearslip no longer needs exploit protection compatibility mode.
+- The car warns you when the phone's location is off.
+- Support Gearslip through Liberapay or Monero, in Settings.
+
+## Known issues
+- Phone calls are unstable right now and may drop or fail to connect.

.github/workflows/codeql.yml

@@ -0,0 +1,50 @@
+name: CodeQL
+
+# Kotlin can only be scanned while it compiles, so this builds the debug app, the same way
+# release.yml does but without a signing key. Workflow files need no build.
+on:
+  push:
+    branches: [main, experimental]
+  pull_request:
+  schedule:
+    - cron: "0 9 * * 1"
+  workflow_dispatch:
+
+jobs:
+  analyze:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write
+      actions: read
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - language: actions
+            build-mode: none
+          - language: java-kotlin
+            build-mode: manual
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: github/codeql-action/init@v4
+        with:
+          languages: ${{ matrix.language }}
+          build-mode: ${{ matrix.build-mode }}
+
+      - if: matrix.build-mode == 'manual'
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "21"
+
+      - if: matrix.build-mode == 'manual'
+        uses: gradle/actions/setup-gradle@v4
+
+      - if: matrix.build-mode == 'manual'
+        run: ./gradlew :gearslip:assembleDebug --no-daemon
+
+      - uses: github/codeql-action/analyze@v4
+        with:
+          category: "/language:${{ matrix.language }}"

.github/workflows/release.yml

@@ -0,0 +1,53 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "21"
+
+      - uses: gradle/actions/setup-gradle@v4
+
+      - name: Write signing key and properties
+        run: |
+          echo "${{ secrets.KEYSTORE_BASE64 }}" | base64 -d > gearslip-release.jks
+          cat > keystore.properties <<EOF
+          storeFile=gearslip-release.jks
+          storePassword=${{ secrets.KEYSTORE_STORE_PASSWORD }}
+          keyAlias=${{ secrets.KEYSTORE_KEY_ALIAS }}
+          keyPassword=${{ secrets.KEYSTORE_KEY_PASSWORD }}
+          EOF
+
+      - name: Build release APK
+        run: ./gradlew :gearslip:assembleRelease
+
+      - name: Locate APK
+        id: apk
+        run: |
+          # The build moves its APKs to <root>/build/Gearslip-<variant>.apk (see renameApk).
+          apk=build/Gearslip-release.apk
+          test -f "$apk" || { echo "no APK at $apk"; ls -R build | head -50; exit 1; }
+          echo "path=$apk" >> "$GITHUB_OUTPUT"
+
+      - name: Create release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: ${{ steps.apk.outputs.path }}
+          # The hand-written notes go first; GitHub adds the full changelog link under them.
+          body_path: .github/release-notes.md
+          generate_release_notes: true
+          # Every release starts as a pre-release: only phones on the Alpha update channel get it.
+          # Once it's tested, untick pre-release on GitHub and everyone gets it.
+          prerelease: true

.github/workflows/trivy.yml

@@ -0,0 +1,34 @@
+name: Security scan
+
+# Trivy looks through the repository for committed secrets and risky workflow or build
+# settings. Findings show under the Security tab, next to CodeQL's and Dependabot's.
+on:
+  push:
+    branches: [main, experimental]
+  pull_request:
+  schedule:
+    - cron: "0 9 * * 1"
+  workflow_dispatch:
+
+jobs:
+  trivy:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: aquasecurity/trivy-action@v0.36.0
+        with:
+          scan-type: fs
+          scanners: vuln,secret,misconfig
+          format: sarif
+          output: trivy.sarif
+          severity: MEDIUM,HIGH,CRITICAL
+
+      - uses: github/codeql-action/upload-sarif@v4
+        if: always()
+        with:
+          sarif_file: trivy.sarif
+          category: trivy

.gitignore

@@ -6,20 +6,35 @@
 /build
 local.properties
 
-# Reference checkouts only - never referenced by the build; safe to delete entirely.
-/cloned-repos
-
-# The head unit certificate. Never committed or shared beyond who Seb sends it to directly.
-/cert
-
-# The release signing key and its passwords. Losing these breaks app updates; leaking them
-# lets anyone sign an APK as Gearslip.
+# Keys
 *.jks
 *.keystore
 keystore.properties
 
-# Local investigation script; not meant for the public repo.
-/docs/cert-sweep.sh
-archive/
+# Native build cache
+.cxx/
+
+# Testing
+/cloned-repos
+docs-internal/
+
+# Internal
+*.pdf
+todo.md
+logs/
+
+# For AI code
+.claude/
 CLAUDE.md
-*.pdf
+
+# Other
+archive/
+.wrangler/
+stats-worker/
+
+# Certificates and keys never go in the repo; the app downloads or imports them on the phone.
+*.p12
+*.pfx
+*.pem
+*.crt
+*.key

CARS.md

@@ -0,0 +1,49 @@
+# Cars
+
+Drivers who share usage notes tell us which cars Gearslip works in. This list comes from
+those notes, and from our own testing. A car shows up here once Gearslip has reached its
+screen at least once.
+
+The year is the one the car reports. Some cars report the year of the head unit instead,
+and some don't say.
+
+## Works
+
+| Car | Year | Head unit |
+|---|---|---|
+| Audi | | MIB2+ (Alpine) |
+| Audi | | Harman |
+| Chevrolet, with myChevrolet | 2019, 2020, 2021 | myChevrolet |
+| Chevrolet, with MyLink | 2017 | MyLink |
+| Dacia | | Media Nav (LG ULC 4.1) |
+| Dacia | | LG ULC 4.5 |
+| Ford | 2018 | SYNC 3.0 (Panasonic) |
+| Ford Fiesta | 2019 | SYNC 3.2 (Panasonic) |
+| Ford Fusion | 2018 | SYNC 3.1 (Panasonic) |
+| Jeep Cherokee | 2019 | Uconnect 8.4 (Delphi) |
+| MG | 2019 | Desay SV |
+| Ram 1500 | 2018 | Uconnect 8.4 (Panasonic) |
+| Škoda | 2018 | MIB Standard2 (TechniSat) |
+| Subaru Outback | 2020 | Denso |
+| Toyota RAV4 | 2020 | Pioneer T1 |
+| Volkswagen | 2018 | MIB Standard2 (Delphi) |
+| Volkswagen | 2024 | ICAS3 |
+| Volvo XC90 | 2022 | SPA Plus (Mitsubishi Electric) |
+| Wuling | 2021 | Desay SV |
+| [LIVI](https://github.com/f-io/LIVI), the open-source head unit | | |
+
+## Not working yet
+
+| Car | Year | What happens |
+|---|---|---|
+| Honda | 2016 | The connection drops before Gearslip reaches the screen. |
+| Honda | 2019 | The connection drops before Gearslip reaches the screen. |
+| Mitsubishi Attrage | 2020 | The connection drops before Gearslip reaches the screen. |
+
+Some cars reject Gearslip's certificate before they say what they are, so they can't appear
+here by name. Most of these are from around 2020 or later.
+
+## Add your car
+
+Turn on usage notes in Gearslip's setup or Settings, and drive once. If your car is missing
+or listed wrongly, open an issue.

CLA.md

@@ -0,0 +1,102 @@
+# Gearslip Contributor License Agreement
+
+Version 1.0, October 2026
+
+Thank you for contributing to Gearslip. This agreement lets Twink Software LLC, the company
+behind Gearslip, use your contribution. You keep the copyright in your work. You sign once,
+and the agreement covers every contribution you make to Gearslip, past and future.
+
+## Why we ask
+
+Gearslip is free software under the GNU Affero General Public License, version 3 (the
+"AGPL"). Twink Software LLC also sells commercial licenses to companies that cannot meet the
+AGPL's terms, and that income helps pay for the project. Offering your code on those terms
+needs your permission, and this agreement gives it.
+
+## 1. Definitions
+
+- **"We"** and **"us"** mean Twink Software LLC, a California limited liability company
+  (Secretary of State entity number B20260081700), under that name or any other, and its
+  successors and assigns.
+- **"You"** means the person who signs this agreement.
+- **"Contribution"** means any work of authorship, such as code, documentation, or images,
+  that you submit to Gearslip, whether before or after you sign. A submission includes a
+  pull request, patch, or issue attachment sent to a repository or channel we manage. It
+  excludes anything you mark in writing as "Not a Contribution".
+
+## 2. Copyright license
+
+You grant us, and anyone who receives software from us, a perpetual, worldwide,
+non-exclusive, no-charge, royalty-free, irrevocable license to reproduce, prepare derivative
+works of, publicly display, publicly perform, sublicense, and distribute your Contributions
+and derivative works of them.
+
+This license lets us offer your Contributions under licenses other than the AGPL, including
+commercial licenses.
+
+## 3. Patent license
+
+You grant us, and anyone who receives software from us, a perpetual, worldwide,
+non-exclusive, no-charge, royalty-free, irrevocable patent license to make, have made, use,
+offer to sell, sell, import, and otherwise transfer your Contributions. This license covers
+only the patent claims you can license that your Contribution, alone or combined with
+Gearslip, would infringe.
+
+If anyone sues claiming that Gearslip or a Contribution infringes a patent, the patent
+licenses granted to that party for Gearslip end on the date the suit is filed.
+
+## 4. Our promise to you
+
+As long as we distribute a Contribution, we will also offer it under the AGPL or another
+license approved by the Open Source Initiative. Your work will always stay available as
+free software.
+
+## 5. Your promises
+
+You promise that:
+
+1. **The work is yours.** Each Contribution is your original creation, and you have the
+   right to grant these licenses.
+2. **Your employer agrees.** If your employer has rights in what you create, you have its
+   permission to contribute on its behalf, or it has waived its rights in your
+   Contributions.
+3. **You name other people's work.** If any part of a Contribution is not your own, you say
+   so when you submit it, and you name its source and its license.
+4. **You'll tell us of changes.** If any of these promises stops being true, you will tell
+   us.
+
+## 6. No warranty
+
+You provide your Contributions "as is", without warranties or conditions of any kind. You do
+not have to provide support for them.
+
+## 7. No obligation
+
+We are not required to use or include any Contribution.
+
+## 8. General
+
+- California law governs this agreement.
+- This agreement does not change the rights you have under the AGPL in Gearslip as
+  released.
+- We may publish a new version of this agreement. A new version applies only to
+  Contributions you make after you sign it; this version keeps covering the ones you made
+  under it.
+
+## Signing
+
+Most contributors sign on GitHub: the CLA Assistant bot comments on your first pull request,
+and you sign there with one click. Your GitHub account then serves as your signature.
+
+To sign by hand instead, fill in the following and send it to us on Matrix. The address is
+on the [Seb3thehacker GitHub profile](https://github.com/Seb3thehacker).
+
+Name: ______________________________
+
+GitHub username: ______________________________
+
+Email: ______________________________
+
+Signature: ______________________________
+
+Date: ______________________________

CONTRIBUTING.md

@@ -0,0 +1,55 @@
+# Contributing to Gearslip
+
+Thanks for helping. Bug reports from real cars are the most useful thing you can send, so
+start there if you aren't sure where to begin.
+
+## Reporting a bug
+
+Open an issue on [GitHub](https://github.com/Seb3thehacker/gearslip/issues) and include:
+
+- your car's make, model, and year, and whether the head unit is the original one; and
+- the log from the drive. Open Logs on the phone app's home screen and tap Share log.
+
+The log records your phone, its Android version, the Gearslip version, the head unit, and
+why the connection ended. Most car bugs can't be fixed without it. Head units often report
+only a part number, so the log can't name your car for you.
+
+## Building
+
+You need Android Studio, or the Android SDK with JDK 21. Gradle downloads the NDK, CMake,
+and the speech library on the first build.
+
+```
+./gradlew :gearslip:assembleDebug
+```
+
+The APK lands at `build/Gearslip-debug.apk`. It installs as Gearslip Dev, next to the
+regular app.
+
+## Pull requests
+
+Work happens on the `experimental` branch, which merges into `main` at each release. Base your
+branch on `experimental`, and open your pull request against it.
+
+- Keep each pull request to one change, and explain the problem it solves.
+- Say how you tested it: which car or head unit, which phone, and which apps.
+- Code written with AI tools is welcome. Read it, test it, and stand behind it as you would
+  your own.
+- Gearslip asks for no adb, root, or Shizuku. A feature must work with ordinary Android
+  permissions and on-device consent dialogs.
+
+## Writing
+
+Text that users read, such as screens, release notes, and docs, follows Strunk's
+[*The Elements of Style*](https://www.gutenberg.org/ebooks/37134). In short: use the active
+voice, state things positively, cut needless words, and use the serial comma.
+
+## License
+
+Gearslip is licensed under AGPL-3.0, and your contributions are too. Twink Software LLC, which
+owns Gearslip, also sells a commercial license, described in [NOTICE.md](NOTICE.md).
+
+Before we can merge your first pull request, you sign the
+[Contributor License Agreement](CLA.md). You keep the copyright in your work, and it stays
+available as free software; the agreement lets us offer it under the commercial license too.
+A bot comments on your pull request with a link, and signing takes one click.

NOTICE.md

@@ -1,16 +1,9 @@
 # License
 
-Gearslip is licensed under the **GNU Affero General Public License v3.0** (see `LICENSE`).
+Gearslip is licensed under the GNU Affero General Public License v3.0. The full text is in `LICENSE`.
 
-In short: you're free to use, run, and modify it. If you modify it — or run a modified
-version as a service others use over a network — the AGPL requires you to make your source
-changes available on the same terms. That obligation follows the code even when you don't
-redistribute a binary, which is what makes the AGPL fit for something that can run as a
-background service.
+You may use, run, and modify Gearslip freely. If you distribute a modified version, or let others use one over a network, you must publish your changes under the same license. The obligation follows the code even when you hand out no binary, which suits software that runs as a background service.
 
 ## Commercial licensing
 
-If the AGPL's terms don't work for you — for example, you want to use Gearslip privately
-without being required to publish your changes — a separate commercial license is available
-directly from the author. Terms (including any restrictions on modification) are set on a
-case-by-case basis. Contact me though Matrix (on my profile) to discuss one.
+If the AGPL's terms don't work for you, the author sells a separate commercial license. The usual case is a company that wants to use Gearslip privately without publishing its changes. Terms, including any limits on modification, are set case by case. Contact me on Matrix; the address is on my profile.

README.md

@@ -2,42 +2,136 @@
 
 # Gearslip
 
-Bring any app to your car screen.
+An Android Auto alternative built for everyone.
+
+
+[![forthebadge](https://forthebadge.com/badges/compatibility-club-penguin.svg)](https://forthebadge.com)
+
+[<img src="https://raw.githubusercontent.com/ImranR98/Obtainium/main/assets/graphics/badge_obtainium.png" alt="Get it on Obtainium" height="80">](https://apps.obtainium.imranr.dev/redirect?r=obtainium://add/https://github.com/Seb3thehacker/gearslip)
+
+Questions, ideas?
+[Join the discussion on Matrix](https://matrix.to/#/!mf0_mgBd5KqKpc9FfX_wHp1jFCcwAtPrndIn_oGIyMk?via=matrix.org).
+
+## Which cars work
+
+Most cars work. Starting around 2020, some cars added newer security standards that reject
+Gearslip's certificate, and Gearslip can't run in those cars. [CARS.md](CARS.md) lists the
+cars drivers have confirmed.
 
 ## What Gearslip is
 
 Gearslip is an Android Auto client for the phone. It speaks the Android Auto protocol
-directly to a car head unit over USB, with no Google software in the path. Gearslip acts
-as a Car App Library host: an app that ships a car interface hands Gearslip a template,
-and Gearslip renders that template natively on the car screen. Nothing is mirrored from
-the phone. For apps without a car interface, Gearslip offers a separate screen-sharing
-mode.
+directly to a car head unit, over USB or wirelessly, with no Google software in the path.
+Gearslip acts as a Car App Library host: an app that ships a car interface hands Gearslip
+a template, and Gearslip renders that template natively on the car screen. Nothing is
+mirrored from the phone. For apps without a car interface, Gearslip offers a separate
+screen-sharing mode.
 
-The author reverse-engineered the protocol for interoperability, so that a client other
-than Google's own can talk to a car head unit.
+| | |
+|---|---|
+| ![The launcher, with apps grouped into phone, maps, music, and messaging](docs/screenshots/launcher.png) | ![Vela Maps giving turn-by-turn directions, with the music player beside the map](docs/screenshots/navigation.png) |
+| Apps sorted by kind. A check marks the ones that work. | Vela Maps navigating, with the player beside it. |
+| ![ViVi Music's song, art, and controls in Gearslip's player](docs/screenshots/music.png) | ![A new message card over Organic Maps](docs/screenshots/message.png) |
+| ViVi Music in Gearslip's player. | A new message, read aloud at a tap, over the map. |
+| ![The dashboard, with the weather, the next calendar event, and recent notifications](docs/screenshots/dashboard.png) | ![DuckDuckGo open in Gearslip's web browser](docs/screenshots/web.png) |
+| The weather, your next event, and what you missed. | Browse the web while parked. |
+
+## Features
+
+- **Phone calls.** Dial from a keypad, or search your contacts, then confirm before the
+  call goes out. When a call comes in, answer or decline it on the car screen.
+- **Navigation.** Gearslip hosts real Car App Library map apps on the car screen.
+  Organic Maps, OsmAnd, and Flitsmeister work today. Vela runs, with rough
+  edges.
+- **Music.** Browse, play, and queue tracks from a car-enabled media app, with a Now
+  Playing view, an Up Next queue, and lyrics. Type a search, and apps that accept one
+  play the best match.
+- **The web.** A browser template with its own on-screen keyboard, for anything that
+  doesn't ship a car interface of its own.
+- **Weather and the day ahead.** A dashboard screen shows the week's calendar next to
+  the current and coming weather.
+- **Voice.** Tap the mic, or press the talk button on the wheel, and say "navigate to the
+  nearest gas station", "play Daft Punk", or "call Mom". Say "help" for the full list.
+  Speech turns into text on the phone, and nothing you say leaves it.
+- **Messages.** New messages appear as a small card on the car screen. Gearslip reads
+  each one aloud, and you reply by voice or with a quick reply. Music pauses while
+  Gearslip speaks or listens. Speech runs on the phone, so it needs no Google account.
+- **Notifications.** Only messages, missed calls, alarms, and reminders interrupt you.
+  The rest wait on the dashboard.
+- **Your apps, your order.** The launcher groups apps by kind: phone, maps, music,
+  messaging, and the rest. Press and hold an app to move it.
+- **Car controls.** Steering wheel buttons, control knobs, and D-pads all work.
+- **Themes.** Choose flat buttons or skeuomorphic ones that look like real keys.
 
 ## Status
 
+- **Wired or wireless.** Plug the phone into the car's USB port, or, in a car with wireless
+  Android Auto, tap Connect wirelessly and pick the car. Pair the phone with the car over
+  Bluetooth first.
+- **Setup walks you through it.** First launch asks for the Android Auto certificate,
+  then one permission at a time, each with a plain reason and an Allow or Skip. A help
+  screen inside the car answers anything setup didn't cover.
 - **Templated apps work.** Gearslip renders all 16 template types that the Car App
-  Library defines, and it draws its own keyboard for search and sign-in. It has been
-  tested against several real navigation and media apps.
-- **Media playback works.** Gearslip lets you browse and control car-enabled media apps
-  from the car screen, with lyrics and playback state, over the same host connection.
-- **Audio reaches the car by capturing playback, not by mirroring the screen.** Android
-  requires a screen-share style consent dialog and indicator for this, even though
-  Gearslip never reads the screen; that grant is the only way a non-privileged app can
-  tap another app's audio. The consent normally repeats every drive; the app's own setup
-  steps include two optional adb commands that reduce it to a one-time grant.
-- **A real head unit needs a certificate that Google controls.** A head unit accepts only
-  a phone identity that chains to Google's Automotive Link certificate authority, and
-  Google alone issues those certificates. Gearslip does not ship one. Without it,
-  Gearslip runs and renders correctly against a debug harness, but a real car rejects the
-  connection. A leaked certificate exists that older head units accept; newer firmware
-  and Google's reference tooling reject it.
+  Library defines, and it draws its own keyboard for search, sign-in, and text fields.
+  It has been tested against several real navigation and media apps.
+- **Gearslip works with [LIVI](https://github.com/f-io/LIVI),** the open-source head unit
+  used in homemade car dashboards.
+- **Some apps refuse Gearslip.** Spotify, Waze, and Google Messages use a version of
+  Google's car library that accepts only Android Auto itself. Spotify still plays through
+  Gearslip's own player.
+- **Calls use the car's Bluetooth,** as they do in Android Auto. Pair the phone with the
+  car to hear calls through its speakers.
+- **Music reaches the car over Bluetooth or USB.** Setup asks which. Bluetooth is the
+  default: Android never asks for permission, and your map app's voice reaches the car
+  too. USB sounds a little clearer, with no delay, but Android shows a screen-share
+  consent dialog once per drive. Gearslip never reads the screen; capturing playback is
+  the only way an ordinary app can pass another app's audio along.
 - **Gearslip needs no adb, root, or Shizuku.** Every feature relies on an ordinary
-  Android permission or an on-device consent dialog. The two adb commands mentioned
-  above, for audio, are the sole exception: both are optional, and both only remove a
-  dialog that the driver would otherwise see once per drive.
+  Android permission or an on-device consent dialog. For USB audio, setup offers two
+  optional adb commands: one removes the audio dialog for good, and the other keeps
+  notifications visible while audio plays.
+- **Updates come from GitHub.** Once a day, Gearslip checks this repository's latest
+  release. When a new version is out, it downloads the APK, checks it against GitHub's
+  SHA-256, and installs it through Android's own installer. Turn off automatic checks in
+  Settings.
+
+## Usage notes
+
+Gearslip can send short notes that show which cars it works in. They stay off unless you
+turn them on, in setup or in Settings.
+
+- **When they go out.** When you open Gearslip, at most once a day, and after each drive.
+  Nothing runs in the background.
+- **What they carry.** The Gearslip version and which boxes you ticked, plus whatever
+  those boxes cover: the Android version and whether the phone runs GrapheneOS, the phone
+  model, whether a car connected that day, and each car's head unit, model, year, screen
+  size, and connection result, with whether that drive used the cable or wireless and
+  whether music went over USB or Bluetooth. If you tick it, how each drive went: how far
+  the connection got, how long it lasted, and how it ended. Settings shows the exact note. Untick a phone detail, and
+  the server drops the copy it kept.
+- **What they leave out.** Your name, accounts, location, contacts, messages, and
+  anything you type or play.
+- **How phones are counted.** A random number counts each phone once. The server keeps
+  only a salted hash of it.
+- **Where they go.** To Gearslip's server. Like any website, it sees your IP address when a
+  note arrives, and it doesn't store it.
+
+Turn the notes off, and they stop at once.
+
+## How Gearslip is made
+
+Gearslip is my beloved child. I decide what it does and how it looks, and Claude writes nearly
+all of the code. I test every change myself before it ships: in a real car, with both a
+GrapheneOS phone and a stock Android phone, and on [LIVI](https://github.com/f-io/LIVI), the
+open-source head unit software. I watch the phone's temperature too, so a new feature doesn't
+cook it. Then I beg my friends to try it in their cars, so it works in as many makes, models,
+and years as possible. If something breaks, that's on me, so please open an issue.
+
+## Contributing
+
+Bug reports from real cars help most, and pull requests are welcome.
+[CONTRIBUTING.md](CONTRIBUTING.md) explains what to put in a report, which branch to work
+on, and the one-time agreement you sign before your first pull request merges.
 
 ## Building
 
@@ -57,6 +151,23 @@ keystore. Without them, the debug build still works.
 [docs/BUILDING_APPS.md](docs/BUILDING_APPS.md) specifies how to write apps that Gearslip
 can render: templated apps, media apps, and the Gearslip app protocol.
 
+## How Gearslip talks to cars
+
+Gearslip is an independent program, written to work with car head units. What it knows of
+the protocol comes from public open-source projects such as
+[aasdk](https://github.com/opencardev/aasdk) and open-android-auto, and it contains none
+of Google's Android Auto code.
+
+Gearslip ships without a certificate. On first launch you choose where yours comes from:
+download the one the aasdk project publishes, or import a file of your own. The
+certificate stays on your phone. Gearslip never uploads, backs up, or logs it.
+
+## Trademarks
+
+Android, Android Auto, Google Messages, and Waze are trademarks of Google LLC. Spotify is
+a trademark of Spotify AB. Gearslip is not affiliated with, endorsed by, or sponsored by
+any of these companies. All other names belong to their owners.
+
 ## License
 
 Gearslip is licensed under AGPL-3.0; see [LICENSE](LICENSE). The author offers a separate

docs/BUILDING_APPS.md

@@ -1,11 +1,12 @@
 # Building apps for Gearslip
 
-Gearslip renders three kinds of app on a car screen. This page specifies all three.
+Gearslip renders four kinds of app on a car screen. This page specifies all four.
 
 | Kind | What it is | Status |
 | --- | --- | --- |
 | [Templated apps](#templated-apps) | An AndroidX Car App Library app. Gearslip hosts it. | Works today |
 | [Media apps](#media-apps) | A `MediaBrowserService` that opted in to Android Auto. | Works today |
+| [Messaging apps](#messaging-apps) | An app whose notifications opted in to Android Auto. | Works today |
 | [Gearslip apps](#gearslip-apps) | A native Gearslip screen, described over binder. | Specified here; not yet implemented |
 
 Write a templated app when your app fits the Car App Library's templates, because it runs today
@@ -29,11 +30,11 @@ any other host.
 Your app decides which hosts may render it, through the `HostValidator` your `CarAppService`
 returns.
 
-Gearslip declares `android.car.permission.TEMPLATE_RENDERER`, and the library's own
-`HostValidator` accepts any host holding it. If you build your validator with
-`HostValidator.Builder` and no allowlist, Gearslip already passes, and you need nothing below.
-Add an allowlist entry when you wrote a custom validator, or when you want to name Gearslip
-explicitly:
+Gearslip declares `android.car.permission.TEMPLATE_RENDERER`. Car App Library 1.8.0-beta01
+and earlier, and 1.9.0-alpha01, accept any host holding it, so Gearslip passes the default
+validator. From 1.8.0-rc01 and 1.9.0-alpha02 the library checks that permission only on
+Android Automotive, so on a phone Gearslip passes only when your allowlist names it. Add this
+entry:
 
 ```xml
 <!-- res/values/arrays.xml -->
@@ -143,7 +144,14 @@ existing video pipe. Gearslip never reads those pixels back.
 
 Gearslip then reports which part of that surface the driver can see. Treat the visible area as
 the region safe for your own controls, and the stable area as the region that never gets
-covered. Gearslip keeps its chrome to a top bar, so both areas are the surface minus that bar.
+covered. Gearslip reports the same area for both, and it depends on the template:
+
+| Template | What Gearslip covers |
+| --- | --- |
+| `NavigationTemplate` | A strip along the bottom for the trip estimate |
+| `MapWithContentTemplate`, `MapTemplate`, and the place list and route preview templates | A content pane on the left |
+
+The turn card and map buttons float over the visible area, as they do in Android Auto.
 
 Your app receives four gestures, never raw touches: `onClick`, `onScroll`, `onFling` and
 `onScale`. Coordinates are surface pixels. Scroll distances follow `GestureDetector`'s
@@ -197,6 +205,53 @@ can start it playing on connection.
 
 ---
 
+## Messaging apps
+
+Gearslip shows conversations from the notifications your app already posts, as Android Auto
+does. Your app needs no car screen of its own.
+
+Gearslip lists a messaging app when its car descriptor declares notifications:
+
+```xml
+<!-- res/xml/automotive_app_desc.xml -->
+<automotiveApp>
+    <uses name="notification" />
+</automotiveApp>
+```
+
+Reference it from the same `com.google.android.gms.car.application` meta-data that a media app
+uses. Opening your tile on the car screen shows your recent conversations.
+
+### Posting messages
+
+Post each conversation as a `MessagingStyle` notification. Gearslip reads the conversation
+title, each message's sender and text, and whether the chat is a group, and shows the last eight
+messages. Leave the sender empty on the phone owner's own messages; Gearslip treats a message
+with no sender as one the driver sent.
+
+Gearslip reads new messages aloud and lets the driver reply by voice or with a quick reply. For
+that, attach two actions, either to the notification or to its `WearableExtender`:
+
+- **Reply:** an action carrying a `RemoteInput` that allows free-form input. Gearslip fills it
+  with the driver's reply and fires the action's intent.
+- **Mark as read:** an action with `SEMANTIC_ACTION_MARK_AS_READ`. Gearslip shows a Mark read
+  button when you provide it.
+
+### Which notifications interrupt the driver
+
+Gearslip pops up a card for a conversation, a notification with a reply action, or a
+notification in the `msg`, `missed_call`, `alarm`, `reminder` or `event` category. A channel
+below default importance never pops up. Every other notification waits quietly on the
+dashboard.
+
+Gearslip drops these altogether:
+
+- ongoing notifications and group summaries;
+- the `transport`, `progress`, `service`, `sys` and `navigation` categories; and
+- media notifications, because the player already shows them.
+
+---
+
 ## Gearslip apps
 
 This section specifies protocol version 1. Gearslip does not yet implement it.
@@ -376,7 +431,7 @@ long strings. Send a screen that fits, rather than one Gearslip has to cut.
   "densityDpi": 160,
   "batteryPercent": 82,
   "charging": true,
-  "vehicle": "Uconnect"
+  "vehicle": "Honda"
 }
 ```
 
@@ -416,6 +471,7 @@ home-screen pane comes later. Anything that needs its own rendering belongs in a
 
 ## Further reading
 
-- [README.md](../README.md) - what Gearslip is and how to build it.
+- [README.md](../README.md) - what Gearslip is.
+- [CONTRIBUTING.md](../CONTRIBUTING.md) - how to build Gearslip and report bugs.
 - [Android for Cars App Library](https://developer.android.com/training/cars/apps) - the
   reference for templated apps.

docs/icon/archive/gearslip-icon-rounded.svg

@@ -1,14 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg" width="432" height="432" viewBox="0 0 108 108">
-  <defs>
-    <linearGradient id="trail" x1="73.4" y1="46.0" x2="95.8" y2="44.5" gradientUnits="userSpaceOnUse">
-      <stop offset="0%" stop-color="#8C1F1F" stop-opacity="0"/>
-      <stop offset="100%" stop-color="#8C1F1F" stop-opacity="0.7"/>
-    </linearGradient>
-  </defs>
-  <rect width="108" height="108" fill="#0c0c0d"/>
-  <circle cx="54" cy="54" r="52" fill="#131415"/>
-  <path d="M 73.23,47.15 L 94.77,51.90 L 96.89,37.05 L 73.57,44.78 Z" fill="url(#trail)"/>
-  <path d="M 54.00,27.00 L 59.99,19.91 Q 61.02,18.69 62.50,19.30 L 72.52,23.45 Q 74.00,24.07 73.87,25.66 L 73.23,33.31 Q 73.09,34.91 73.70,36.39 L 80.39,52.52 Q 81.00,54.00 82.22,55.03 L 88.09,59.99 Q 89.31,61.02 88.70,62.50 L 84.55,72.52 Q 83.93,74.00 82.34,73.87 L 73.09,73.09 Q 73.09,73.09 73.09,73.09 L 73.09,73.09 Q 73.09,73.09 73.09,73.09 L 73.87,82.34 Q 74.00,83.93 72.52,84.55 L 62.50,88.70 Q 61.02,89.31 59.99,88.09 L 54.00,81.00 Q 54.00,81.00 54.00,81.00 L 54.00,81.00 Q 54.00,81.00 54.00,81.00 L 48.01,88.09 Q 46.98,89.31 45.50,88.70 L 35.48,84.55 Q 34.00,83.93 34.13,82.34 L 34.91,73.09 Q 34.91,73.09 34.91,73.09 L 34.91,73.09 Q 34.91,73.09 34.91,73.09 L 25.66,73.87 Q 24.07,74.00 23.45,72.52 L 19.30,62.50 Q 18.69,61.02 19.91,59.99 L 27.00,54.00 Q 27.00,54.00 27.00,54.00 L 27.00,54.00 Q 27.00,54.00 27.00,54.00 L 19.91,48.01 Q 18.69,46.98 19.30,45.50 L 23.45,35.48 Q 24.07,34.00 25.66,34.13 L 34.91,34.91 Q 34.91,34.91 34.91,34.91 L 34.91,34.91 Q 34.91,34.91 34.91,34.91 L 34.13,25.66 Q 34.00,24.07 35.48,23.45 L 45.50,19.30 Q 46.98,18.69 48.01,19.91 L 54.00,27.00 Q 54.00,27.00 54.00,27.00 L 54.00,27.00 Q 54.00,27.00 54.00,27.00 Z" fill="#8B9096"/>
-  <path d="M 92.78,34.42 L 99.94,37.20 Q 101.43,37.78 101.34,39.37 L 100.67,50.20 Q 100.58,51.80 99.03,52.19 L 91.58,54.08 Q 90.03,54.47 90.13,52.87 L 91.19,35.44 Q 91.29,33.84 92.78,34.42 Z" fill="#8C1F1F"/>
-  <circle cx="54" cy="54" r="12" fill="#0c0c0d"/>
-</svg>

docs/icon/gearslip-icon.svg

@@ -5,7 +5,6 @@
       <stop offset="100%" stop-color="#8C1F1F" stop-opacity="0.7"/>
     </linearGradient>
   </defs>
-  <rect width="108" height="108" fill="#0c0c0d"/>
   <circle cx="54" cy="54" r="52" fill="#131415"/>
   <path d="M 73.23,47.15 L 94.77,51.90 L 96.89,37.05 L 73.57,44.78 Z" fill="url(#trail)"/>
   <path d="M 54.00,27.00 L 61.02,18.69 L 74.00,24.07 L 73.09,34.91 L 81.00,54.00 L 89.31,61.02 L 83.93,74.00 L 73.09,73.09 L 73.09,73.09 L 74.00,83.93 L 61.02,89.31 L 54.00,81.00 L 54.00,81.00 L 46.98,89.31 L 34.00,83.93 L 34.91,73.09 L 34.91,73.09 L 24.07,74.00 L 18.69,61.02 L 27.00,54.00 L 27.00,54.00 L 18.69,46.98 L 24.07,34.00 L 34.91,34.91 L 34.91,34.91 L 34.00,24.07 L 46.98,18.69 L 54.00,27.00 Z" fill="#8B9096"/>

gearslip/build.gradle.kts

@@ -24,16 +24,27 @@ val keystoreProperties = Properties().apply {
     ).firstOrNull { it.exists() }?.inputStream()?.use { load(it) }
 }
 
+// Keeps build output out of the module folder: <root>/build/gearslip/... instead of
+// <root>/gearslip/build/..., so everything this project produces lands under one
+// root-level build/ directory. Set before android {}, which works out the path to R8's default
+// rules from it.
+layout.buildDirectory.set(rootProject.layout.buildDirectory.dir("gearslip"))
+
 android {
     namespace = "app.seb3thehacker.gearslip"
     compileSdk = 37
 
     defaultConfig {
         applicationId = "app.seb3thehacker.gearslip"
-        minSdk = 35
+        minSdk = 31
         targetSdk = 37
-        versionCode = 3
-        versionName = "0.0.03-pre"
+        versionCode = 9
+        // -PgearslipVersionName=0.1.99-test makes a build that thinks it's older, to try the updater.
+        versionName = project.findProperty("gearslipVersionName")?.toString() ?: "0.3.00-alpha"
+        manifestPlaceholders["appLabel"] = "Gearslip"
+        // Where opted-in phones send their daily usage note: the stats-worker/ Worker's address,
+        // set as gearslipStatsUrl in gradle.properties. Left empty, nothing is ever sent.
+        buildConfigField("String", "STATS_URL", "\"${project.findProperty("gearslipStatsUrl") ?: ""}\"")
     }
 
     signingConfigs {
@@ -52,19 +63,41 @@ android {
     buildTypes {
         release {
             signingConfig = signingConfigs.findByName("release")
+            isMinifyEnabled = true
+            isShrinkResources = true
+            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
+        }
+        // Its own package, so a debug build installs beside the release one instead of over it.
+        // Signed with the release key when it's here: both builds declare the car template
+        // permission, and Android refuses a second app declaring it under a different key.
+        debug {
+            applicationIdSuffix = ".dev"
+            signingConfigs.findByName("release")?.let { signingConfig = it }
+            manifestPlaceholders["appLabel"] = "Gearslip Debug"
+            // -Pr8 shrinks a debug build like a release one, to test R8 in the debug install.
+            if (project.hasProperty("r8")) {
+                isMinifyEnabled = true
+                isShrinkResources = true
+                proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
+            }
         }
     }
 
-    // Keeps build output out of the module folder: <root>/build/gearslip/... instead of
-    // <root>/gearslip/build/..., so everything this project produces lands under one
-    // root-level build/ directory.
-    layout.buildDirectory.set(rootProject.layout.buildDirectory.dir("gearslip"))
+    buildFeatures {
+        buildConfig = true
+    }
 
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_21
         targetCompatibility = JavaVersion.VERSION_21
     }
 
+    defaultConfig {
+        // Speech-to-text (sherpa-onnx, in jniLibs) ships for 64-bit ARM only: every phone
+        // Gearslip runs on, and one copy of the native library instead of four.
+        ndk { abiFilters += "arm64-v8a" }
+    }
+
     testOptions {
         // GearslipLog calls android.util.Log, which is a stub on the local JVM.
         unitTests.isReturnDefaultValues = true
@@ -96,6 +129,7 @@ dependencies {
     implementation(platform(libs.androidx.compose.bom))
     implementation(libs.androidx.compose.ui)
     implementation(libs.androidx.compose.material3)
+    implementation(libs.commons.compress)
     implementation(libs.androidx.compose.material.icons.core)
     implementation(libs.androidx.activity.compose)
     implementation(libs.androidx.lifecycle.runtime.compose)
@@ -104,6 +138,7 @@ dependencies {
     // their Bundleables deserialize into.
     implementation(libs.androidx.car.app)
     implementation(libs.androidx.car.app.projected)
+    implementation(libs.androidx.media)
     testImplementation(libs.junit)
 }
 
@@ -112,3 +147,4 @@ tasks.withType<KotlinJvmCompile>().configureEach {
         jvmTarget.set(JvmTarget.JVM_21)
     }
 }
+

gearslip/proguard-rules.pro

@@ -0,0 +1,20 @@
+# R8 shrinks the release build; these keep what it can't see being used.
+
+# Names stay readable, so stack traces in shared logs need no mapping file. Shrinking does
+# the real work on size.
+-dontobfuscate
+
+# Gearslip hosts other apps' car screens: their templates arrive as Bundles, and the car
+# library rebuilds them by class name and reflection. Any model class an app might send has to
+# survive, used by Gearslip's code or not.
+-keep class androidx.car.app.** { *; }
+
+# Speech-to-text: the native library calls back into these classes by name.
+-keep class com.k2fsa.sherpa.onnx.** { *; }
+
+# commons-compress refers to optional codecs Gearslip doesn't ship.
+-dontwarn org.tukaani.xz.**
+-dontwarn com.github.luben.zstd.**
+-dontwarn org.brotli.dec.**
+-dontwarn org.objectweb.asm.**
+-dontwarn org.osgi.**

gearslip/src/debug/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Debug-only override of the main icon background (src/debug/res wins over src/main/res),
+     so a debug install is never mistaken for a release one on the home screen. -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:pathData="M0,0h108v108h-108z"
+        android:fillColor="#f5c518"/>
+    <path
+        android:pathData="M54,2 A52,52 0 1,1 53.99,2 Z"
+        android:fillColor="#e6b400"/>
+</vector>

gearslip/src/debug/res/drawable/ic_launcher_foreground.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Debug-only override of the main icon foreground, to go with the yellow debug background:
+     a charcoal gear rather than light grey, and a yellow centre hole to match the background
+     instead of the release icon's near-black. -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path android:pathData="M 66.69,49.48 L 80.91,52.61 L 82.31,42.81 L 66.92,47.91 Z">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:type="linear"
+                android:startX="66.80"
+                android:startY="48.70"
+                android:endX="81.61"
+                android:endY="47.71">
+                <item android:offset="0" android:color="#00E5484D"/>
+                <item android:offset="1" android:color="#E5484D"/>
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:pathData="M 54.00,36.18 L 58.64,30.70 L 67.20,34.24 L 66.60,41.40 L 71.82,54.00 L 77.30,58.64 L 73.76,67.20 L 66.60,66.60 L 66.60,66.60 L 67.20,73.76 L 58.64,77.30 L 54.00,71.82 L 54.00,71.82 L 49.36,77.30 L 40.80,73.76 L 41.40,66.60 L 41.40,66.60 L 34.24,67.20 L 30.70,58.64 L 36.18,54.00 L 36.18,54.00 L 30.70,49.36 L 34.24,40.80 L 41.40,41.40 L 41.40,41.40 L 40.80,34.24 L 49.36,30.70 L 54.00,36.18 Z"
+        android:fillColor="#2E3033"/>
+    <path
+        android:pathData="M 78.61,40.70 L 85.31,43.29 L 84.74,52.55 L 77.78,54.31 Z"
+        android:fillColor="#E5484D"/>
+    <path
+        android:pathData="M54,46.08 A7.92,7.92 0 1,1 53.99,46.08 Z"
+        android:fillColor="#e6b400"/>
+</vector>

gearslip/src/main/AndroidManifest.xml

@@ -4,6 +4,7 @@
 
     <!-- The projected WebView loads real pages; without this every load fails silently. -->
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />
 
     <!--
       Phone mirroring. Android refuses to hand over a MediaProjection unless a foreground
@@ -12,12 +13,29 @@
     -->
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PROJECTION" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MICROPHONE" />
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
 
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE_LOCATION" />
 
+    <!--
+        Wireless Android Auto: Bluetooth reaches the paired car's Android Auto service, which
+        hands over its Wi-Fi details; Gearslip then joins that network to reach the car.
+    -->
+    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+    <uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
+    <uses-permission
+        android:name="android.permission.NEARBY_WIFI_DEVICES"
+        android:usesPermissionFlags="neverForLocation" />
+    <!-- Android 17 drops an app's traffic to the car's Wi-Fi without this. -->
+    <uses-permission android:name="android.permission.ACCESS_LOCAL_NETWORK" />
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
+    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
+
     <!-- The dashboard opened from the car clock: today's agenda and current weather. -->
     <uses-permission android:name="android.permission.READ_CALENDAR" />
 
@@ -39,6 +57,21 @@
         android:name="android.permission.WRITE_SECURE_SETTINGS"
         tools:ignore="ProtectedPermissions" />
 
+    <!--
+        Phone calls on the car screen. READ_PHONE_STATE and READ_CALL_LOG together are what a
+        call's own state (ringing, in progress) and the incoming number need; READ_CONTACTS
+        turns that number into a name; ANSWER_PHONE_CALLS lets the driver pick up from here.
+        Declining a call, and the caller ID itself, need Gearslip set as the phone's caller ID
+        and spam app too - an on-device consent, not a permission declared here.
+    -->
+    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
+    <uses-permission android:name="android.permission.READ_CALL_LOG" />
+    <uses-permission android:name="android.permission.READ_CONTACTS" />
+    <uses-permission android:name="android.permission.ANSWER_PHONE_CALLS" />
+
+    <!-- Placing a call from the car screen's dial pad or contacts list needs this. -->
+    <uses-permission android:name="android.permission.CALL_PHONE" />
+
     <!--
       Declared, not just requested. Templated apps decide whether to talk to a host by asking
       whether it holds this permission (HostValidator.isValidHost checks it before falling back
@@ -54,6 +87,14 @@
     <uses-feature android:name="android.hardware.usb.accessory" android:required="true" />
 
     <queries>
+    <!-- Named directly: current builds have no launcher-category entry point for the MAIN/
+         LAUNCHER query below to find, so the setup guide's Android Auto check needs this to see
+         whether the package is installed at all. -->
+    <package android:name="com.google.android.projection.gearhead" />
+    <!-- The opt-in usage note names the OS: GrapheneOS's setup app and /e/OS's app store give
+         them away (UsageStats.osName). -->
+    <package android:name="app.grapheneos.setupwizard" />
+    <package android:name="foundation.e.apps" />
     <intent>
         <action android:name="android.intent.action.MAIN" />
         <category android:name="android.intent.category.LAUNCHER" />
@@ -66,13 +107,21 @@
     <intent>
         <action android:name="android.media.browse.MediaBrowserService" />
     </intent>
+    <!-- Speech: without these, Android hides the recognizer and the voice from us and
+         SpeechRecognizer reports none installed even when one is. -->
+    <intent>
+        <action android:name="android.speech.RecognitionService" />
+    </intent>
+    <intent>
+        <action android:name="android.intent.action.TTS_SERVICE" />
+    </intent>
 </queries>
 
 <application
         android:allowBackup="false"
         android:icon="@mipmap/ic_launcher"
         android:roundIcon="@mipmap/ic_launcher"
-        android:label="Gearslip"
+        android:label="${appLabel}"
         android:supportsRtl="true"
         android:theme="@style/Theme.Gearslip">
 
@@ -95,6 +144,7 @@
             android:name=".GearslipActivity"
             android:exported="true"
             android:launchMode="singleTop"
+            android:windowSoftInputMode="adjustResize"
             android:configChanges="orientation|screenSize|screenLayout|smallestScreenSize|keyboardHidden|uiMode|density|locale|layoutDirection|fontScale">
 
             <intent-filter>
@@ -102,6 +152,18 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
 
+        </activity>
+
+        <!--
+          Answers the car's USB connection on GearslipActivity's behalf. Kept apart from the
+          activity so Settings can switch off just this (AppSettings.setGearslipEnabled) and leave
+          the head unit to Android Auto, without disabling the screen the switch is on.
+        -->
+        <activity-alias
+            android:name=".GearslipUsbAccessory"
+            android:targetActivity=".GearslipActivity"
+            android:exported="true">
+
             <intent-filter>
                 <action android:name="android.hardware.usb.action.USB_ACCESSORY_ATTACHED" />
             </intent-filter>
@@ -109,7 +171,12 @@
             <meta-data
                 android:name="android.hardware.usb.action.USB_ACCESSORY_ATTACHED"
                 android:resource="@xml/accessory_filter" />
-        </activity>
+        </activity-alias>
+
+        <!-- Dev builds' test message: its Reply and Mark as read actions land here. -->
+        <receiver
+            android:name=".notify.TestMessageReceiver"
+            android:exported="false" />
 
         <service
             android:name=".mirror.MirrorService"
@@ -121,11 +188,14 @@
             android:exported="false"
             android:foregroundServiceType="location" />
 
-        <!-- Holds the capture session that carries a media app's audio to the car. -->
+        <!--
+          Holds the capture session that carries a media app's audio to the car. It also claims
+          the microphone, so voice replies can hear the driver with the phone locked.
+        -->
         <service
             android:name=".audio.AudioCaptureService"
             android:exported="false"
-            android:foregroundServiceType="mediaProjection" />
+            android:foregroundServiceType="mediaProjection|microphone" />
 
         <!--
           Touch on the car screen is replayed onto the phone through this service.
@@ -158,5 +228,21 @@
                 <action android:name="android.service.notification.NotificationListenerService" />
             </intent-filter>
         </service>
+
+        <!--
+          Sees incoming calls before they ring, so the car screen can show the caller and
+          decline it. Inert until the driver sets Gearslip as the phone's caller ID and spam
+          app, under Settings > Apps > Default apps - the same consent a call-blocking app asks
+          for, not a privileged one.
+        -->
+        <service
+            android:name=".call.GearslipCallScreening"
+            android:exported="true"
+            android:label="Gearslip calls"
+            android:permission="android.permission.BIND_SCREENING_SERVICE">
+            <intent-filter>
+                <action android:name="android.telecom.CallScreeningService" />
+            </intent-filter>
+        </service>
     </application>
 </manifest>

gearslip/src/main/java/app/seb3thehacker/gearslip/AppSettings.kt

@@ -1,14 +1,17 @@
 package app.seb3thehacker.gearslip
 
+import android.content.ComponentName
 import android.content.Context
+import android.content.pm.PackageManager
 
 /** User-facing preferences. Read fresh on every session, so changes apply on the next connect. */
 object AppSettings {
 
     private const val PREFS = "gearslip_settings"
     private const val KEY_STARTUP_URL = "startup_url"
-    private const val KEY_SEEN_COMPAT_WARNING = "seen_compat_warning"
-    private const val KEY_DEBUG_MODE = "debug_mode"
+    private const val KEY_SKIPPED_CERT_SETUP = "skipped_cert_setup"
+    private const val KEY_SEEN_PERMISSIONS_SETUP = "seen_permissions_setup"
+    private const val KEY_GEARSLIP_ENABLED = "gearslip_enabled"
 
     private fun prefs(context: Context) =
         context.applicationContext.getSharedPreferences(PREFS, Context.MODE_PRIVATE)
@@ -28,23 +31,58 @@ object AppSettings {
         prefs(context).edit().putString(KEY_STARTUP_URL, value.trim()).apply()
     }
 
-    /** Whether the newer-car compatibility warning has already been shown and dismissed once. */
-    fun hasSeenCompatWarning(context: Context): Boolean =
-        prefs(context).getBoolean(KEY_SEEN_COMPAT_WARNING, false)
+    /** Whether the certificate setup screen has been deliberately skipped. */
+    fun hasSkippedCertSetup(context: Context): Boolean =
+        prefs(context).getBoolean(KEY_SKIPPED_CERT_SETUP, false)
 
-    fun setSeenCompatWarning(context: Context) {
-        prefs(context).edit().putBoolean(KEY_SEEN_COMPAT_WARNING, true).apply()
+    fun setSkippedCertSetup(context: Context) {
+        prefs(context).edit().putBoolean(KEY_SKIPPED_CERT_SETUP, true).apply()
+    }
+
+    /** Whether the one-by-one permissions wizard has already run once. */
+    fun hasSeenPermissionsSetup(context: Context): Boolean =
+        prefs(context).getBoolean(KEY_SEEN_PERMISSIONS_SETUP, false)
+
+    fun setSeenPermissionsSetup(context: Context) {
+        prefs(context).edit().putBoolean(KEY_SEEN_PERMISSIONS_SETUP, true).apply()
     }
 
     /**
-     * Debug mode: full protocol tracing in the log, and the developer screens (live logs, car
-     * preview) on the home screen. On by default while the project is pre-release.
+     * Whether Gearslip is allowed to claim the USB accessory connection. Off leaves the app
+     * installed but disables the GearslipUsbAccessory alias that answers
+     * USB_ACCESSORY_ATTACHED, so a real Android Auto head unit (or Google's own app) gets the
+     * connection instead - the two fight over it otherwise, since only one app can win the
+     * accessory handoff. The alias is separate from GearslipActivity itself - the activity that
+     * shows this very switch - so turning it off can't disable the screen you're looking at.
+     * On by default.
      */
-    fun debugMode(context: Context): Boolean =
-        prefs(context).getBoolean(KEY_DEBUG_MODE, true)
+    fun gearslipEnabled(context: Context): Boolean =
+        prefs(context).getBoolean(KEY_GEARSLIP_ENABLED, true)
 
-    fun setDebugMode(context: Context, value: Boolean) {
-        prefs(context).edit().putBoolean(KEY_DEBUG_MODE, value).apply()
-        GearslipLog.debug = value
+    fun setGearslipEnabled(context: Context, value: Boolean) {
+        prefs(context).edit().putBoolean(KEY_GEARSLIP_ENABLED, value).apply()
+        applyGearslipEnabled(context)
+    }
+
+    /**
+     * Makes the USB alias match the saved switch. Called at every launch as well, so a switch
+     * saved without the alias following it (an older build crashed right there) heals itself.
+     * Only the alias changes: the driver's "always open with Gearslip" choice for the car is kept.
+     */
+    fun applyGearslipEnabled(context: Context) {
+        val value = gearslipEnabled(context)
+        val appContext = context.applicationContext
+        // The class name comes from the code's namespace, not the package: a debug build installs
+        // as ".dev", but the alias is still app.seb3thehacker.gearslip.GearslipUsbAccessory.
+        val component = ComponentName(appContext.packageName, "${GearslipActivity::class.java.`package`!!.name}.GearslipUsbAccessory")
+        val state = if (value) {
+            PackageManager.COMPONENT_ENABLED_STATE_DEFAULT
+        } else {
+            PackageManager.COMPONENT_ENABLED_STATE_DISABLED
+        }
+        val pm = appContext.packageManager
+        if (pm.getComponentEnabledSetting(component) == state) return
+        runCatching { pm.setComponentEnabledSetting(component, state, PackageManager.DONT_KILL_APP) }
+            .onFailure { GearslipLog.e("could not switch the USB connection ${if (value) "on" else "off"}", it) }
     }
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/CarFocus.kt

@@ -0,0 +1,28 @@
+package app.seb3thehacker.gearslip
+
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * Who has the car's screen: Gearslip, or the car's own interface. Android Auto's "Exit" hands the
+ * screen back to the car with the session still running, so music keeps playing; the car's own
+ * Android Auto button brings Gearslip back. [GearslipRunner] fills in [request] while connected.
+ */
+object CarFocus {
+
+    private val projectedFlow = MutableStateFlow(true)
+
+    /** False while the car shows its own interface. */
+    val projected: StateFlow<Boolean> = projectedFlow
+
+    @Volatile internal var request: (() -> Unit)? = null
+
+    /** Asks the car to show its own interface. Does nothing when no car is connected. */
+    fun exitToCar() {
+        request?.invoke()
+    }
+
+    internal fun set(projected: Boolean) {
+        projectedFlow.value = projected
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/CertDownloader.kt

@@ -0,0 +1,52 @@
+package app.seb3thehacker.gearslip
+
+import java.io.ByteArrayOutputStream
+import java.net.HttpURLConnection
+import java.net.URL
+
+/**
+ * Fetches the publicly available head unit certificate and key from the opencardev/aasdk
+ * repository on GitHub. The app ships no certificates; it downloads them only when the
+ * user chooses to, the same way a browser would.
+ */
+object CertDownloader {
+
+    private val log = GearslipLog.tagged("DOWNL")
+
+    private const val BASE = "https://raw.githubusercontent.com/opencardev/aasdk/main/cert"
+    private const val CRT = "$BASE/headunit.crt"
+    private const val KEY = "$BASE/headunit.key"
+    private const val CONNECT_TIMEOUT_MS = 10_000
+    private const val READ_TIMEOUT_MS = 15_000
+
+    class Downloaded(val certificatePem: String, val privateKeyPem: String)
+
+    /** Fetches both files; throws with a readable message on any failure. */
+    fun fetch(): Downloaded {
+        log.i("fetching certificate from $BASE")
+        val crt = fetch(CRT, "certificate")
+        val key = fetch(KEY, "private key")
+        log.i("downloaded certificate (${crt.length} bytes) and key (${key.length} bytes)")
+        return Downloaded(crt, key)
+    }
+
+    private fun fetch(url: String, label: String): String {
+        val body = try {
+            val conn = (URL(url).openConnection() as HttpURLConnection).apply {
+                connectTimeout = CONNECT_TIMEOUT_MS
+                readTimeout = READ_TIMEOUT_MS
+            }
+            conn.inputStream.use { input ->
+                val out = ByteArrayOutputStream()
+                val buf = ByteArray(4096)
+                var n: Int
+                while (input.read(buf).also { n = it } != -1) out.write(buf, 0, n)
+                out.toString(Charsets.UTF_8)
+            }
+        } catch (e: Exception) {
+            throw RuntimeException("could not download the $label: ${e.message}", e)
+        }
+        if (body.isBlank()) throw RuntimeException("the $label file is empty")
+        return body
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/CertProvider.kt

@@ -2,6 +2,7 @@ package app.seb3thehacker.gearslip
 
 import android.content.Context
 import android.net.Uri
+import java.io.ByteArrayOutputStream
 import java.io.File
 import java.security.KeyStore
 import java.security.cert.X509Certificate
@@ -14,7 +15,9 @@ import java.security.cert.X509Certificate
  *
  *  1. **Imported** in the app (Settings > Certificate): a PKCS#12 file plus its password,
  *     copied into the app's private storage.
- *  2. **Staged over adb** into the app's external files directory, the way the spike has
+ *  2. **Downloaded** from the public opencardev/aasdk repository. Fetched only when the
+ *     user asks; the app never ships or hosts the certificate.
+ *  3. **Staged over adb** into the app's external files directory, the way the spike has
  *     always done it. Still honoured, so existing setups keep working untouched:
  *
  *       openssl pkcs12 -export -in headunit.crt -inkey headunit.key \
@@ -23,7 +26,7 @@ import java.security.cert.X509Certificate
  *
  *     Default password is "aaspike" (kept as-is so an already-staged phone.p12 doesn't need
  *     regenerating); a `phone.pass` file next to it overrides it.
- *  3. A freshly generated self-signed cert, which a real head unit rejects (see
+ *  4. A freshly generated self-signed cert, which a real head unit rejects (see
  *     SPIKE_FINDINGS.md).
  */
 object CertProvider {
@@ -34,7 +37,7 @@ object CertProvider {
     private const val DEFAULT_PASSWORD = "aaspike"
     private const val IMPORT_DIR = "identity"
 
-    enum class Kind { IMPORTED, ADB_STAGED, SELF_SIGNED }
+    enum class Kind { IMPORTED, DOWNLOADED, ADB_STAGED, SELF_SIGNED }
 
     class Identity(
         val keyStore: KeyStore,
@@ -44,7 +47,10 @@ object CertProvider {
         val kind: Kind = Kind.SELF_SIGNED,
     )
 
-    /** Loaded fresh each call, so a newly imported or pushed cert takes effect on the next connect. */
+    /**
+     * The identity for the next connection. A newly imported or pushed cert takes effect on the
+     * next connect: see [loadFromFiles] for how the cache notices.
+     */
     fun load(context: Context): Identity = loadFromFiles(context) ?: run {
         val generated = SelfSignedCert.generate()
         Identity(
@@ -62,7 +68,38 @@ object CertProvider {
      */
     fun loadSupplied(context: Context): Identity? = loadFromFiles(context)
 
+    /**
+     * Unlocking a PKCS#12 file takes about a second on a Pixel 6, which a head unit waiting for
+     * its first reply may not wait out. So the unlocked identity is kept, keyed on the files it
+     * could come from: importing, downloading, removing or pushing a cert changes the key.
+     */
+    @Volatile private var cached: Pair<String, Identity>? = null
+
+    private fun sourcesKey(context: Context): String {
+        val dir = context.getExternalFilesDir(null)
+        val files = listOf(
+            importedFile(context, P12_NAME),
+            downloadedFile(context, P12_NAME),
+            dir?.let { File(it, P12_NAME) },
+            dir?.let { File(it, PASS_NAME) },
+        )
+        return files.joinToString("|") { f -> f?.let { "${it.path}:${it.lastModified()}:${it.length()}" } ?: "-" }
+    }
+
+    /** Unlocks the certificate ahead of time, so the first connection doesn't wait on it. */
+    fun warm(context: Context) {
+        runCatching { loadFromFiles(context) }
+    }
+
     private fun loadFromFiles(context: Context): Identity? {
+        val key = sourcesKey(context)
+        cached?.let { (k, identity) -> if (k == key) return identity }
+        val identity = unlockFromFiles(context) ?: return null
+        cached = key to identity
+        return identity
+    }
+
+    private fun unlockFromFiles(context: Context): Identity? {
         val imported = importedFile(context, P12_NAME)
         if (imported.isFile) {
             runCatching {
@@ -70,6 +107,13 @@ object CertProvider {
             }.onFailure { log.e("could not load the imported certificate - trying the next source", it) }
         }
 
+        val downloaded = downloadedFile(context, P12_NAME)
+        if (downloaded.isFile) {
+            runCatching {
+                return loadP12(downloaded, DEFAULT_PASSWORD, "downloaded certificate", Kind.DOWNLOADED)
+            }.onFailure { log.e("could not load the downloaded certificate - trying the next source", it) }
+        }
+
         val dir = context.getExternalFilesDir(null)
         val staged = dir?.let { File(it, P12_NAME) }
         if (dir != null && staged != null && staged.isFile) {
@@ -113,17 +157,84 @@ object CertProvider {
 
     fun hasImported(context: Context): Boolean = importedFile(context, P12_NAME).isFile
 
-    /** Drops the imported identity; the next source in line (adb-staged, then self-signed) takes over. */
+    /** Whether a downloaded certificate is stored (may or may not also be imported). */
+    fun hasDownloaded(context: Context): Boolean = downloadedFile(context, P12_NAME).isFile
+
+    /** Drops the imported identity; the next source in line (downloaded, adb-staged, then self-signed) takes over. */
     fun removeImported(context: Context) {
         importedFile(context, P12_NAME).delete()
         importedFile(context, PASS_NAME).delete()
         log.i("removed the imported certificate")
     }
 
+    /** Drops the downloaded identity. */
+    fun removeDownloaded(context: Context) {
+        downloadedFile(context, P12_NAME).delete()
+        downloadedFile(context, PASS_NAME).delete()
+        log.i("removed the downloaded certificate")
+    }
+
+    /** Whether any certificate is available (imported, downloaded, or adb-staged). */
+    fun hasAnyCert(context: Context): Boolean =
+        hasImported(context) || hasDownloaded(context) || hasAdbStaged(context)
+
+    private fun hasAdbStaged(context: Context): Boolean =
+        context.getExternalFilesDir(null)?.let { File(it, P12_NAME).isFile } == true
+
+    /**
+     * Validates raw PKCS#12 bytes with [password] and, if good, writes them as the imported
+     * identity. Used when the app assembles a certificate in memory (e.g. from a download)
+     * rather than importing from a file picker.
+     */
+    fun importFromBytes(context: Context, p12Bytes: ByteArray, password: String): Identity {
+        val staging = File(context.cacheDir, "import-$P12_NAME")
+        try {
+            staging.writeBytes(p12Bytes)
+            val identity = loadP12(staging, password, "imported certificate", Kind.IMPORTED)
+
+            val target = importedFile(context, P12_NAME)
+            target.parentFile?.mkdirs()
+            staging.copyTo(target, overwrite = true)
+            importedFile(context, PASS_NAME).writeText(password)
+            log.i("imported a certificate from bytes: ${identity.certificate.subjectX500Principal}")
+            return identity
+        } finally {
+            staging.delete()
+        }
+    }
+
+    /**
+     * Downloads the publicly available head unit certificate from the opencardev/aasdk
+     * repository, converts it from PEM to PKCS#12, and stores it ready for use.
+     * Runs synchronously (caller is responsible for threading). Throws on any failure.
+     */
+    fun downloadAndImport(context: Context): Identity {
+        val download = CertDownloader.fetch()
+        val result = PemKeyParser.build(download.certificatePem, download.privateKeyPem)
+
+        val target = downloadedFile(context, P12_NAME)
+        target.parentFile?.mkdirs()
+        val p12Password = DEFAULT_PASSWORD
+        val keyStore = result.keyStore
+        val p12Bytes = ByteArrayOutputStream().use { stream ->
+            keyStore.store(stream, p12Password.toCharArray())
+            stream.toByteArray()
+        }
+        target.writeBytes(p12Bytes)
+        downloadedFile(context, PASS_NAME).writeText(p12Password)
+
+        log.i("downloaded and stored certificate: ${result.certificate.subjectX500Principal}")
+        return Identity(keyStore, result.certificate, p12Password.toCharArray(),
+            "downloaded certificate (opencardev/aasdk)", Kind.DOWNLOADED)
+    }
+
     // The imported files live in the app's private internal storage (not the external files
     // dir), so other apps cannot read the key, and `adb uninstall` clearing it is expected.
     private fun importedFile(context: Context, name: String) = File(File(context.filesDir, IMPORT_DIR), name)
 
+    private fun downloadedFile(context: Context, name: String) =
+        File(File(context.filesDir, "$IMPORT_DIR-downloaded"), name)
+
     private fun importedPassword(context: Context): String =
         importedFile(context, PASS_NAME).takeIf { it.isFile }?.readText().orEmpty()
 

gearslip/src/main/java/app/seb3thehacker/gearslip/Changelog.kt

@@ -0,0 +1,96 @@
+package app.seb3thehacker.gearslip
+
+/**
+ * What changed in each release, newest first, shown on the car screen after an update (and on
+ * the phone). Only the changes a driver would notice. Plain words, short lines: this is read in
+ * a parked car.
+ */
+object Changelog {
+
+    class Release(val versionCode: Int, val versionName: String, val changes: List<String>)
+
+    val releases = listOf(
+        Release(
+            9, "0.3.00-alpha",
+            listOf(
+                "Wireless Android Auto: pair the phone with the car once, and leave the cable at home.",
+                "Voice control is built in. Say \"navigate to a gas station\", \"play\" a song or artist, or open an app by name.",
+                "\"Navigate to\" picks the nearest place and stops at the map app's start screen, so you only tap Start.",
+                "Gearslip turns speech into text on the phone, with no Google account. Download the voice models once in setup.",
+                "The car's rotary knob moves between buttons, so cars without a touchscreen work too.",
+                "Choose how music reaches the car: Bluetooth, or USB with no delay. Gearslip offers to pair with the car the first time.",
+                "The car speaks each turn from your map app, and shows the directions on its own display where it can.",
+                "The car shows what's playing, and music apps get their own like, shuffle and repeat buttons.",
+                "Pick how the car's buttons look. Change it any time in the car's settings.",
+                "A new destination mid-route replaces the old route, and switching map apps ends the old app's route.",
+                "The car warns you when the phone's location is off.",
+                "Gearslip finds new versions and installs them for you.",
+                "More cars play music over USB, show a sharper picture, and put taps where you press.",
+                "On GrapheneOS, Gearslip no longer needs exploit protection compatibility mode.",
+                "The app is half the size it was.",
+            ),
+        ),
+        Release(
+            8, "0.2.00-alpha",
+            listOf(
+                "Exit takes you to the car's own screen. Tap Android Auto on the car to come back.",
+                "Gearslip listens through the car's microphone when the car has one, so voice works with the phone in a pocket.",
+                "A voice reply sends when its bar runs out, even over road noise or the radio. Say \"cancel\" or \"change it\" before then.",
+                "Maps turn dark when the car switches to night mode.",
+                "A moving map no longer makes the car screen fall behind your taps.",
+                "Gearslip asks to send sound to the car as soon as you connect, so videos in the web browser play in the car too.",
+                "Cars that offer more than one kind of music audio, such as the 2022 Dacia Jogger, play sound again.",
+                "When the car shows a keyboard, you can type on the phone instead. The car's keyboard is taller too.",
+                "Every car screen has a back button.",
+                "App icons show whether an app works in Gearslip. Metrolist works and shows the green check.",
+                "LIVI connects again, and touch works on cars with a second screen.",
+                "The phone's Settings screen has a new layout, with What's new and the setup guide at the top.",
+                "You can choose to send short usage notes that help the project. They hold no name, account, or location, and they're off unless you turn them on.",
+                "Searching inside a media app moved to Settings > Experimental features.",
+                "Under Settings > Media audio, the choices are now Phone audio and Car audio.",
+                "Logs leave out your location and the car's serial number.",
+            ),
+        ),
+        Release(
+            7, "0.1.10-alpha",
+            listOf(
+                "The launcher groups your apps: Phone, Maps, Music, Messaging, Web, Screen sharing, and Settings.",
+                "To move an app, press and hold it on the launcher, then tap Move left or Move right.",
+                "MapQuest and Flitsmeister work in Gearslip and show the green check.",
+                "Spotify has one tile. If Spotify isn't open on the phone, tap Open Spotify to start it.",
+                "Flick a map and it glides on, as it does in Android Auto.",
+                "The map picks up where it left off when you come back from another screen.",
+                "Search boxes in map apps are larger and easier to read.",
+                "Map apps keep the right icons on their buttons after they update.",
+                "When Gearslip asks \"Do you want to reply?\", a bar shows how long it will listen. The bar stops while you speak.",
+                "Gearslip fits its picture to wide car screens and keeps it clear of the edges the car crops.",
+                "Gearslip answers the car's connection checks correctly. Some cars, Audis among them, hung up after a second without this.",
+                "Google Maps no longer shows up as a messaging app.",
+            ),
+        ),
+        Release(
+            6, "0.1.0-alpha",
+            listOf(
+                "Messaging apps such as Signal and Molly open to your recent chats.",
+                "Gearslip reads a message aloud, and you reply by voice. Say \"cancel\" or \"change it\" before it sends, or tap a quick reply such as your arrival time.",
+                "Voice works on any phone, GrapheneOS included. Gearslip turns speech into text itself, so it needs no Google account.",
+                "New messages show as a small card at the top right, even while you drive. A bar shows how long until the card closes or the reply sends.",
+                "Only messages, missed calls, alarms, and reminders pop up. Everything else waits on the dashboard.",
+                "The map stays loaded when you switch screens, so it no longer flashes black.",
+                "Map apps draw more reliably and keep their connection when the phone is locked.",
+                "The Home button shows your map app, so it no longer appears twice.",
+                "The next turn shows in the nav bar when you leave the map.",
+                "Steering wheel buttons, control knobs, and D-pads now work. If yours don't, open an issue on GitHub.",
+                "To see the whole song title and artist in the nav bar, choose Settings > Player in the nav bar > Song title.",
+                "Choose miles or kilometres under Settings > Units.",
+                "Try the voice assistant and the vehicle data screen under Settings > Experimental features.",
+                "Logs now say why a car ended the connection.",
+                "Spotify, Waze, and Google Messages updated to a version of Google's car library that only accepts Android Auto itself. Their own car screens won't open in Gearslip. Spotify still plays through the Gearslip player, which has the green check.",
+                "Calls go through the car's Bluetooth, as they do in Android Auto. Pair your phone with the car to hear calls on its speakers.",
+            ),
+        ),
+    )
+
+    /** The release that matches this build, if it has notes. */
+    val current: Release? get() = releases.firstOrNull { it.versionCode == BuildConfig.VERSION_CODE }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/GearslipActivity.kt

@@ -8,13 +8,17 @@ import android.hardware.usb.UsbAccessory
 import android.hardware.usb.UsbManager
 import android.media.projection.MediaProjection
 import android.media.projection.MediaProjectionManager
+import android.net.Uri
 import android.os.Bundle
 import android.os.ParcelFileDescriptor
+import android.provider.Settings
 import android.view.MotionEvent
 import android.view.Surface
 import android.view.WindowManager
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
 import androidx.activity.enableEdgeToEdge
 import androidx.activity.result.contract.ActivityResultContracts.StartActivityForResult
 import android.content.res.Configuration
@@ -27,6 +31,7 @@ import app.seb3thehacker.gearslip.car.CarEnvironment
 import app.seb3thehacker.gearslip.car.CarSettings
 import app.seb3thehacker.gearslip.car.CarUi
 import app.seb3thehacker.gearslip.car.Prefetch
+import app.seb3thehacker.gearslip.stats.UsageStats
 import app.seb3thehacker.gearslip.ui.GearslipApp
 import app.seb3thehacker.gearslip.ui.GearslipTheme
 import java.io.FileInputStream
@@ -40,8 +45,12 @@ import java.io.FileOutputStream
  * rotation or theme change from recreating it and dropping the connection.
  */
 class GearslipActivity : ComponentActivity(), Projection {
+    private val mainHandler = android.os.Handler(android.os.Looper.getMainLooper())
+
 
     private var descriptor: ParcelFileDescriptor? = null
+    /** The wireless session's socket, when the car came over Wi-Fi instead of USB. */
+    private var wirelessSocket: java.net.Socket? = null
     private var runner: GearslipRunner? = null
     private var screenProjector: ScreenProjector? = null
     private var worker: Thread? = null
@@ -69,7 +78,13 @@ class GearslipActivity : ComponentActivity(), Projection {
     private val audioPermission = registerForActivityResult(
         androidx.activity.result.contract.ActivityResultContracts.RequestPermission(),
     ) { granted ->
-        if (granted) askAudioCapture() else {
+        if (granted) askAudioCapture()
+        else if (!shouldShowRequestPermissionRationale(android.Manifest.permission.RECORD_AUDIO)) {
+            // Refused twice: Android now says no without showing anything, so the phone must.
+            GearslipLog.w("audio: record permission blocked - Android no longer asks")
+            CarAudio.micBlocked()
+            micBlockedNotice.value = true
+        } else {
             GearslipLog.w("audio: record permission declined")
             CarAudio.denied()
         }
@@ -82,51 +97,49 @@ class GearslipActivity : ComponentActivity(), Projection {
         } else {
             GearslipLog.w("audio: capture consent declined")
             CarAudio.denied()
+            if (!CarSettings.audioChoiceAsked) offerBluetooth.value = true
         }
     }
 
+    /** Raised when the microphone permission is blocked; see [MicBlockedDialog]. */
+    private val micBlockedNotice = kotlinx.coroutines.flow.MutableStateFlow(false)
+
+    /** Raised once, after the first "no" to the capture dialog; see [AudioChoiceDialog]. */
+    private val offerBluetooth = kotlinx.coroutines.flow.MutableStateFlow(false)
+
     private val detachReceiver = object : BroadcastReceiver() {
         override fun onReceive(context: Context?, intent: Intent?) {
             if (intent?.action == UsbManager.ACTION_USB_ACCESSORY_DETACHED) {
                 GearslipLog.w("accessory detached")
-                closeAccessory()
+                // A wireless session has no accessory to lose; leave it running.
+                if (wirelessSocket == null) closeAccessory()
             }
         }
     }
 
-    /** Hosted map apps need Gearslip to hold location so they can keep it in the background. */
-    private val locationPermission = registerForActivityResult(
-        androidx.activity.result.contract.ActivityResultContracts.RequestPermission(),
-    ) { granted -> if (granted) Prefetch.warm(this, force = true) }
-
-    /** The car dashboard's agenda card; declined just leaves it empty rather than asking again. */
-    private val calendarPermission = registerForActivityResult(
-        androidx.activity.result.contract.ActivityResultContracts.RequestPermission(),
-    ) { granted -> if (granted) Prefetch.warm(this, force = true) }
+    /** Setting Gearslip as the phone's caller ID and spam app - what lets it decline a ringing call. */
+    private val callScreeningRole = registerForActivityResult(StartActivityForResult()) { result ->
+        if (result.resultCode != RESULT_OK) GearslipLog.w("calls: call screening role declined")
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        if (checkSelfPermission(android.Manifest.permission.ACCESS_FINE_LOCATION) !=
-            android.content.pm.PackageManager.PERMISSION_GRANTED
-        ) locationPermission.launch(android.Manifest.permission.ACCESS_FINE_LOCATION)
-        if (checkSelfPermission(android.Manifest.permission.READ_CALENDAR) !=
-            android.content.pm.PackageManager.PERMISSION_GRANTED
-        ) calendarPermission.launch(android.Manifest.permission.READ_CALENDAR)
-        // Playback capture needs the microphone even though it never records one. Ask for it here,
-        // at the kerb, rather than the first time a song plays: a permission dialog that appears
-        // mid-drive is one the driver has to read and answer at the wheel, and missing it is
-        // indistinguishable from the car link being broken.
-        if (CarSettings.pipeAudio.value &&
-            checkSelfPermission(android.Manifest.permission.RECORD_AUDIO) !=
-            android.content.pm.PackageManager.PERMISSION_GRANTED
-        ) audioPermission.launch(android.Manifest.permission.RECORD_AUDIO)
+        // Location, calendar, the phone/contacts group, and the microphone are asked for one at
+        // a time by PermissionsSetupScreen instead of here, each only after the driver taps
+        // Allow on a screen explaining what it is for. Firing them all from onCreate, unprompted,
+        // is both a bad first impression and unreliable: Android does not consistently show more
+        // than one system permission dialog fired back-to-back, which was silently dropping some.
         enableEdgeToEdge()
         window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
 
         GearslipLog.init(this)
         GearslipLog.installCrashHandler()
         GearslipLog.i("Gearslip ready")
+        app.seb3thehacker.gearslip.wireless.WirelessLink.onConnected = { socket ->
+            runOnUiThread { startWireless(socket) }
+        }
         CarSettings.init(this)
+        AppSettings.applyGearslipEnabled(this)
         // A capture that died without tidying up would leave notifications exposed to every
         // later screen share. Nothing is capturing if the service is not running, so undo it.
         if (!app.seb3thehacker.gearslip.audio.AudioCaptureService.running) {
@@ -137,7 +150,33 @@ class GearslipActivity : ComponentActivity(), Projection {
 
         setContent {
             GearslipTheme {
-                GearslipApp(onDisconnect = ::closeAccessory)
+                GearslipApp(onDisconnect = { closeAccessory() }, onRequestCallScreening = ::requestCallScreeningRole)
+                val offer by offerBluetooth.collectAsState()
+                if (offer) {
+                    fun close() {
+                        CarSettings.markAudioChoiceAsked()
+                        offerBluetooth.value = false
+                    }
+                    app.seb3thehacker.gearslip.ui.AudioChoiceDialog(
+                        onUseBluetooth = {
+                            CarSettings.setPipeAudio(false)
+                            close()
+                        },
+                        onKeepAsking = ::close,
+                    )
+                }
+                val micNotice by micBlockedNotice.collectAsState()
+                if (micNotice) {
+                    app.seb3thehacker.gearslip.ui.MicBlockedDialog(
+                        onOpenSettings = {
+                            micBlockedNotice.value = false
+                            startActivity(
+                                Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", packageName, null)),
+                            )
+                        },
+                        onDismiss = { micBlockedNotice.value = false },
+                    )
+                }
             }
         }
 
@@ -161,6 +200,12 @@ class GearslipActivity : ComponentActivity(), Projection {
     override fun onStart() {
         super.onStart()
         Prefetch.warm(this)
+        UsageStats.onAppOpened(this)
+        app.seb3thehacker.gearslip.update.UpdateChecker.onAppOpened(this)
+        // Back from the app's settings with the microphone turned on: try car audio again.
+        if (checkSelfPermission(android.Manifest.permission.RECORD_AUDIO) == android.content.pm.PackageManager.PERMISSION_GRANTED) {
+            CarAudio.micAllowed()
+        }
     }
 
     override fun onNewIntent(intent: Intent) {
@@ -170,6 +215,7 @@ class GearslipActivity : ComponentActivity(), Projection {
 
     override fun onDestroy() {
         super.onDestroy()
+        app.seb3thehacker.gearslip.wireless.WirelessLink.onConnected = null
         runCatching { unregisterReceiver(detachReceiver) }
         PhoneMirror.onStartRequested = null
         PhoneMirror.onTokenReady = null
@@ -181,6 +227,19 @@ class GearslipActivity : ComponentActivity(), Projection {
         GearslipLog.flush()
     }
 
+    /** Launches the system dialog that offers Gearslip the call-screening role, if it isn't held already. */
+    private fun requestCallScreeningRole() {
+        val roleManager = getSystemService(android.app.role.RoleManager::class.java)
+        if (roleManager == null || !roleManager.isRoleAvailable(android.app.role.RoleManager.ROLE_CALL_SCREENING)) {
+            GearslipLog.w("calls: call screening role unavailable on this phone")
+            return
+        }
+        if (roleManager.isRoleHeld(android.app.role.RoleManager.ROLE_CALL_SCREENING)) return
+        runCatching {
+            callScreeningRole.launch(roleManager.createRequestRoleIntent(android.app.role.RoleManager.ROLE_CALL_SCREENING))
+        }.onFailure { GearslipLog.e("could not ask for the call screening role", it) }
+    }
+
     // --- Media audio --------------------------------------------------------------------
 
     private fun requestAudioCapture() {
@@ -246,6 +305,12 @@ class GearslipActivity : ComponentActivity(), Projection {
 
     private fun handleIntent(intent: Intent?) {
         if (intent?.action != UsbManager.ACTION_USB_ACCESSORY_ATTACHED) return
+        // Switched off in Settings: the system shouldn't route the car here at all, but if it
+        // does, leave the accessory alone.
+        if (!AppSettings.gearslipEnabled(this)) {
+            GearslipLog.i("accessory attached, but Gearslip is switched off - not connecting")
+            return
+        }
         val accessory = intent.getParcelableExtra(UsbManager.EXTRA_ACCESSORY, UsbAccessory::class.java)
         if (accessory == null) {
             GearslipLog.e("attach intent carried no accessory")
@@ -257,10 +322,13 @@ class GearslipActivity : ComponentActivity(), Projection {
     }
 
     private fun start(accessory: UsbAccessory) {
-        if (worker?.isAlive == true) {
-            GearslipLog.w("a run is already in progress")
-            return
-        }
+        // A fresh ATTACHED intent means the system wants a new session, whatever state the old
+        // one is in - closing first guarantees openAccessory() below never fights a descriptor
+        // this same process forgot to release. The old worker thread often isn't alive by this
+        // point anyway (its read loop already died when the head unit dropped the transport),
+        // but the accessory it opened was never explicitly closed, which is what actually blocks
+        // a re-open - a dead thread does not release the file descriptor on its own.
+        closeAccessory()
         describe(accessory)
 
         val manager = getSystemService(UsbManager::class.java)
@@ -283,16 +351,44 @@ class GearslipActivity : ComponentActivity(), Projection {
         worker = Thread { runner.run() }.apply { name = "gearslip"; start() }
     }
 
+    /** A wireless session: the same runner, on the socket [WirelessLink] opened to the car. */
+    private fun startWireless(socket: java.net.Socket) {
+        closeAccessory(stopWireless = false)
+        if (!AppSettings.gearslipEnabled(this)) {
+            GearslipLog.i("wireless: Gearslip is switched off - not connecting")
+            runCatching { socket.close() }
+            return
+        }
+        GearslipLog.i("wireless: starting a session over Wi-Fi to ${socket.inetAddress?.hostAddress}:${socket.port}")
+        wirelessSocket = socket
+        val runner = GearslipRunner(
+            input = socket.getInputStream(),
+            output = socket.getOutputStream(),
+            identityProvider = { CertProvider.load(this) },
+            projection = this,
+            vehicleProfileFor = { info -> VehicleProfiles.find(VehicleProfiles.load(this), info) },
+            wireless = true,
+        )
+        this.runner = runner
+        worker = Thread { runner.run() }.apply { name = "gearslip"; start() }
+    }
+
     private fun describe(accessory: UsbAccessory) {
         GearslipLog.i("accessory: manufacturer=${accessory.manufacturer} model=${accessory.model}")
         GearslipLog.i("           version=${accessory.version} description=${accessory.description}")
     }
 
-    private fun closeAccessory() {
+    private fun closeAccessory() = closeAccessory(stopWireless = true)
+
+    /** Ends the session, wired or wireless. [stopWireless] also drops the car's Bluetooth and Wi-Fi. */
+    private fun closeAccessory(stopWireless: Boolean) {
         runner?.stop()
         SessionReport.print()
         runCatching { descriptor?.close() }
         descriptor = null
+        runCatching { wirelessSocket?.close() }
+        wirelessSocket = null
+        if (stopWireless) app.seb3thehacker.gearslip.wireless.WirelessLink.stop(this)
         runner = null
     }
 
@@ -307,11 +403,16 @@ class GearslipActivity : ComponentActivity(), Projection {
             CarEnvironment.setDisplay(width, height, densityDpi)
             CarEnvironment.start(this)
             showCarUi()
+            app.seb3thehacker.gearslip.car.CarKeys.focusSink = { code, down ->
+                runOnUiThread { screenProjector?.dispatchKey(code, down) }
+            }
         }
     }
 
     override fun onTouch(action: Int, actionIndex: Int, points: List<TouchPoint>) {
-        runOnUiThread {
+        // To the front of the main thread's queue: a touch waiting behind other work is lag the
+        // driver feels, while the work it jumps ahead of can wait a frame.
+        mainHandler.postAtFrontOfQueue {
             // Mirroring drives one phone touch at a time, so it follows the first finger only.
             if (PhoneMirror.active.value) points.firstOrNull()?.let { relayTouch(action, it.x, it.y) }
             else screenProjector?.dispatchTouch(action, actionIndex, points)
@@ -319,8 +420,11 @@ class GearslipActivity : ComponentActivity(), Projection {
     }
 
     override fun onProjectionStopped() {
+        // Before the car UI goes, while the media connection is still up.
+        app.seb3thehacker.gearslip.car.CarServices.pausePhoneMedia()
         runOnUiThread {
             PhoneMirror.requestStop()
+            app.seb3thehacker.gearslip.car.CarKeys.focusSink = null
             screenProjector?.stop()
             screenProjector = null
             surface = null

gearslip/src/main/java/app/seb3thehacker/gearslip/GearslipLog.kt

@@ -32,9 +32,9 @@ object GearslipLog {
     private var file: File? = null
 
     /**
-     * Set from [AppSettings.debugMode]. Off drops the noisy trace output (hex dumps, and
-     * logcat copies of info lines); warnings, errors and the file copy are always kept, so a
-     * crash report is never empty.
+     * Off drops the noisy trace output (hex dumps, and logcat copies of info lines); warnings,
+     * errors and the file copy are always kept, so a crash report is never empty. Always on for
+     * now, while the project is pre-release.
      */
     @Volatile var debug = true
 
@@ -47,13 +47,11 @@ object GearslipLog {
     val version: StateFlow<Int> = liveVersion
 
     fun init(context: Context) {
-        debug = AppSettings.debugMode(context)
         val dir = context.getExternalFilesDir(null) ?: return
         val name = SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US).format(Date())
         file = File(dir, "gearslip-$name.log")
         i("log file: ${file?.absolutePath}")
         SessionReport.init(context)
-        i("debug mode: $debug")
     }
 
     fun snapshot(): List<String> = synchronized(live) { live.toList() }

gearslip/src/main/java/app/seb3thehacker/gearslip/PemKeyParser.kt

@@ -0,0 +1,125 @@
+package app.seb3thehacker.gearslip
+
+import java.io.ByteArrayInputStream
+import java.math.BigInteger
+import java.security.KeyFactory
+import java.security.KeyStore
+import java.security.cert.CertificateFactory
+import java.security.cert.X509Certificate
+import java.security.spec.RSAPrivateCrtKeySpec
+import java.security.spec.RSAPublicKeySpec
+
+/**
+ * Converts a PEM-encoded X.509 certificate and PEM-encoded RSA PKCS#1 private key into a
+ * PKCS#12 [KeyStore], using only standard JCA APIs — no BouncyCastle.
+ *
+ * The DER parsing of the PKCS#1 key is done by hand (matching the same approach used in
+ * [SelfSignedCert] for writing). Android's Conscrypt [KeyFactory] only accepts PKCS#8,
+ * so we translate PKCS#1 → [RSAPrivateCrtKeySpec] ourselves.
+ */
+object PemKeyParser {
+
+    private const val CERT_HEADER = "-----BEGIN CERTIFICATE-----"
+    private const val CERT_FOOTER = "-----END CERTIFICATE-----"
+    private const val KEY_HEADER = "-----BEGIN RSA PRIVATE KEY-----"
+    private const val KEY_FOOTER = "-----END RSA PRIVATE KEY-----"
+
+    class Result(val keyStore: KeyStore, val certificate: X509Certificate)
+
+    /**
+     * Parses PEM strings for the certificate and private key, verifies they match, and
+     * returns a PKCS#12 [KeyStore] ready for [CertProvider] to consume.
+     */
+    fun build(certificatePem: String, privateKeyPem: String, alias: String = "phone"): Result {
+        val cert = parseCertificate(certificatePem)
+        val keySpec = parsePrivateKey(privateKeyPem)
+
+        val kf = KeyFactory.getInstance("RSA")
+        val pubSpec = RSAPublicKeySpec(keySpec.spec.modulus, keySpec.spec.publicExponent)
+        require(kf.generatePublic(pubSpec) == cert.publicKey) {
+            "the certificate's public key does not match the private key"
+        }
+
+        val keyStore = KeyStore.getInstance("PKCS12").apply {
+            load(null, null)
+            setKeyEntry(alias, keySpec.getPrivate(), CharArray(0), arrayOf(cert))
+        }
+        return Result(keyStore, cert)
+    }
+
+    /** Strips PEM headers/footers and decodes the base64 body. */
+    fun parseCertificate(pem: String): X509Certificate {
+        val der = pemToDer(pem, CERT_HEADER, CERT_FOOTER)
+        return CertificateFactory.getInstance("X.509")
+            .generateCertificate(ByteArrayInputStream(der)) as X509Certificate
+    }
+
+    /** Parses an RSA PKCS#1 private key (ASN.1 DER) into a key spec. */
+    fun parsePrivateKey(pem: String): KeySpec {
+        val der = pemToDer(pem, KEY_HEADER, KEY_FOOTER)
+        val integers = readPkcs1Sequence(der)
+        require(integers.size == 9) { "PKCS#1 RSA key needs 9 integers, got ${integers.size}" }
+        val spec = RSAPrivateCrtKeySpec(integers[1], integers[2], integers[3], integers[4], integers[5], integers[6], integers[7], integers[8])
+        val privateKey = KeyFactory.getInstance("RSA").generatePrivate(spec)
+        return KeySpec(spec, privateKey)
+    }
+
+    /** Holds both the spec and the constructed key for matching against a certificate's public key. */
+    class KeySpec(val spec: RSAPrivateCrtKeySpec, private val privateKey: java.security.PrivateKey) {
+        fun getPrivate() = privateKey
+    }
+
+    /** Strips headers and decodes base64. */
+    private fun pemToDer(pem: String, header: String, footer: String): ByteArray {
+        val start = pem.indexOf(header)
+        val end = pem.indexOf(footer)
+        if (start == -1 || end == -1 || end <= start) {
+            throw IllegalArgumentException("not a valid PEM $header block")
+        }
+        val b64 = pem.substring(start + header.length, end)
+            .replace(Regex("\\s+"), "")
+        return java.util.Base64.getDecoder().decode(b64)
+    }
+
+    /**
+     * Parses the inner SEQUENCE of an RSA PKCS#1 DER blob into a list of [BigInteger]s.
+     * Throws if the ASN.1 structure is wrong, so caller gets a clear error rather than a
+     * silent wrong key.
+     */
+    private fun readPkcs1Sequence(der: ByteArray): List<BigInteger> {
+        var pos = 0
+        fun readTag(): Int {
+            require(pos < der.size) { "unexpected end of DER at tag" }
+            return der[pos++].toInt() and 0xFF
+        }
+        fun readLength(): Int {
+            require(pos < der.size) { "unexpected end of DER at length" }
+            val b0 = der[pos++].toInt() and 0xFF
+            if (b0 < 0x80) return b0
+            val numBytes = b0 and 0x7F
+            require(pos + numBytes <= der.size) { "truncated long-form length" }
+            var result = 0
+            repeat(numBytes) {
+                result = (result shl 8) or (der[pos++].toInt() and 0xFF)
+            }
+            return result
+        }
+
+        val outerTag = readTag()
+        require(outerTag == 0x30) { "expected SEQUENCE (0x30), got 0x${outerTag.toString(16)}" }
+        val outerLen = readLength()
+        require(pos + outerLen <= der.size) { "SEQUENCE length $outerLen exceeds remaining data" }
+
+        val integers = mutableListOf<BigInteger>()
+        while (pos < der.size) {
+            val tag = readTag()
+            require(tag == 0x02) { "expected INTEGER (0x02), got 0x${tag.toString(16)} at offset ${pos - 1}" }
+            val len = readLength()
+            require(pos + len <= der.size) { "INTEGER length $len exceeds remaining data" }
+            integers.add(BigInteger(der.copyOfRange(pos, pos + len)))
+            pos += len
+        }
+        require(integers.size == 9) { "PKCS#1 RSA key needs 9 integers, got ${integers.size}" }
+        return integers
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/Protobuf.kt

@@ -31,11 +31,17 @@ object Protobuf {
         return varint(((field shl 3) or 2).toLong()) + varint(bytes.size.toLong()) + bytes
     }
 
+    fun bytesField(field: Int, bytes: ByteArray): ByteArray =
+        varint(((field shl 3) or 2).toLong()) + varint(bytes.size.toLong()) + bytes
+
     fun varintField(field: Int, value: Long): ByteArray =
         varint((field shl 3).toLong()) + varint(value)
 
     /** Reads the single int32 in AuthResponse. Negative values are 10-byte varints. */
-    fun readInt32Field(data: ByteArray, field: Int): Int? {
+    fun readInt32Field(data: ByteArray, field: Int): Int? = readInt64Field(data, field)?.toInt()
+
+    /** Reads a varint field whole, for int64s such as a ping's timestamp. */
+    fun readInt64Field(data: ByteArray, field: Int): Long? {
         var pos = 0
         while (pos < data.size) {
             val (tag, afterTag) = readVarint(data, pos) ?: return null
@@ -45,7 +51,7 @@ object Protobuf {
                 0 -> {
                     val (value, afterValue) = readVarint(data, pos) ?: return null
                     pos = afterValue
-                    if (number == field) return value.toInt()
+                    if (number == field) return value
                 }
                 2 -> {
                     val (len, afterLen) = readVarint(data, pos) ?: return null

gearslip/src/main/java/app/seb3thehacker/gearslip/ScreenProjector.kt

@@ -45,7 +45,19 @@ class ScreenProjector(private val context: Context) {
     /** Tracks the synthetic gesture so injected MotionEvents have a coherent downTime. */
     private var downTime = 0L
 
-    fun start(surface: Surface, width: Int, height: Int, densityDpi: Int, content: @Composable () -> Unit) {
+    /**
+     * [name] names the virtual display so the two callers are told apart from outside the app
+     * (`dumpsys display`): the real car session keeps "gearslip-projection", the on-phone bench
+     * preview passes "gearslip-preview".
+     */
+    fun start(
+        surface: Surface,
+        width: Int,
+        height: Int,
+        densityDpi: Int,
+        name: String = "gearslip-projection",
+        content: @Composable () -> Unit,
+    ) {
         stop()
 
         val displayManager = context.getSystemService(DisplayManager::class.java)
@@ -57,7 +69,7 @@ class ScreenProjector(private val context: Context) {
         // driver on every connect.
         val display = try {
             displayManager.createVirtualDisplay(
-                "gearslip-projection", width, height, densityDpi, surface,
+                name, width, height, densityDpi, surface,
                 DisplayManager.VIRTUAL_DISPLAY_FLAG_PRESENTATION or
                     DisplayManager.VIRTUAL_DISPLAY_FLAG_OWN_CONTENT_ONLY,
             )
@@ -179,6 +191,34 @@ class ScreenProjector(private val context: Context) {
         if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) downTime = 0L
     }
 
+    /**
+     * A key from the car's D-pad or knob, as a hardware key event on the car display. Compose
+     * moves focus between buttons on arrows and Tab, and clicks the focused one on OK/Enter.
+     * [keyCode] of [CarKeys.KEYCODE_SHIFT_TAB] is Tab with Shift held.
+     */
+    fun dispatchKey(keyCode: Int, down: Boolean) {
+        val target = root ?: return
+        // Keys handed straight to the view skip the step where Android leaves touch mode, and in
+        // touch mode Compose's buttons refuse focus, so the knob had nothing to move between.
+        if (target.isInTouchMode) {
+            target.requestFocusFromTouch()
+            GearslipLog.i("keys: left touch mode for the knob/D-pad (now in touch mode: ${target.isInTouchMode})")
+        }
+        // Nothing on the display takes keys until something in it holds focus.
+        if (target.findFocus() == null) target.requestFocus()
+        val shift = keyCode == app.seb3thehacker.gearslip.car.CarKeys.KEYCODE_SHIFT_TAB
+        val code = if (shift) android.view.KeyEvent.KEYCODE_TAB else keyCode
+        val now = SystemClock.uptimeMillis()
+        val event = android.view.KeyEvent(
+            now, now,
+            if (down) android.view.KeyEvent.ACTION_DOWN else android.view.KeyEvent.ACTION_UP,
+            code, 0,
+            if (shift) android.view.KeyEvent.META_SHIFT_ON or android.view.KeyEvent.META_SHIFT_LEFT_ON else 0,
+            android.view.KeyCharacterMap.VIRTUAL_KEYBOARD, 0, 0, android.view.InputDevice.SOURCE_DPAD,
+        )
+        target.dispatchKeyEvent(event)
+    }
+
     fun stop() {
         runCatching { presentation?.dismiss() }
         runCatching { owner?.destroy() }

gearslip/src/main/java/app/seb3thehacker/gearslip/ServiceDiscovery.kt

@@ -20,8 +20,8 @@ object ServiceDiscovery {
 
     /**
      * [widthMargin]/[heightMargin] are the head unit's own numbers (VideoConfiguration fields 3
-     * and 4): pixels of the frame it does not treat as usable UI. Logged, and available to a
-     * vehicle profile, but not applied automatically - what they mean varies by unit.
+     * and 4): pixels of the frame it crops away, split evenly between the two edges, to fit the
+     * frame to a screen of a different shape. A matched vehicle profile's insets override them.
      */
     class VideoConfig(
         val resolution: Int,
@@ -38,11 +38,21 @@ object ServiceDiscovery {
 
         fun pixelCount(): Int = pixelSize()?.let { it.first * it.second } ?: Int.MAX_VALUE
 
+        /** What's left on the car's screen once the margins are cropped off. */
+        fun visibleSize(): Pair<Int, Int>? = pixelSize()?.let { (w, h) -> (w - widthMargin) to (h - heightMargin) }
+
+        /** The margins as the strips of the frame the car UI keeps clear. */
+        fun marginInsets(): Insets = Insets(
+            top = heightMargin / 2, bottom = heightMargin - heightMargin / 2,
+            left = widthMargin / 2, right = widthMargin - widthMargin / 2,
+        )
+
         override fun toString() =
             "$resolutionName @ $frameRateName, density=$density, margin=${widthMargin}x$heightMargin"
     }
 
-    class VideoService(val serviceId: Int, val codecType: Int, val configs: List<VideoConfig>) {
+    /** [displayId] is MediaSinkService field 6: 0, the default, is the main screen. */
+    class VideoService(val serviceId: Int, val codecType: Int, val configs: List<VideoConfig>, val displayId: Int = 0) {
         val codecName: String get() = CODECS[codecType] ?: "unknown($codecType)"
     }
 
@@ -89,6 +99,100 @@ object ServiceDiscovery {
         }
     }
 
+    /**
+     * The media sink to stream to. Gearslip sends raw PCM, so a PCM sink wins: the 2022 Dacia
+     * Jogger (LGE ULC 4.5) lists an AAC media sink on channel 3 before a PCM one on channel 5,
+     * and PCM pushed into the AAC sink was acked but played as silence. With no PCM sink, the
+     * first media sink is the best there is.
+     */
+    fun pickMediaSink(sinks: List<AudioService>): AudioService? {
+        val media = sinks.filter { it.streamType == STREAM_MEDIA }
+        return media.firstOrNull { it.codecType == CODEC_PCM } ?: media.firstOrNull()
+    }
+
+    /**
+     * The channel the car takes "now playing" on (MediaPlaybackStatusService, Service field 9),
+     * which feeds its cluster and media screens. It carries no settings. Null when the car has none.
+     */
+    fun findMediaStatusChannel(response: ByteArray): Int? = findChannelWith(response, 9)
+
+    /** The instrument cluster's turn-by-turn channel (NavigationStatusService, Service field 8). */
+    fun findNavStatusChannel(response: ByteArray): Int? = findChannelWith(response, 8)
+
+    private fun findChannelWith(response: ByteArray, serviceField: Int): Int? =
+        Wire.allBytes(Wire.fields(response), 1).firstNotNullOfOrNull { channel ->
+            val service = Wire.fields(channel)
+            if (service.any { it.number == serviceField }) Wire.varint(service, 1)?.toInt() else null
+        }
+
+    /**
+     * The car's microphone, from MediaSourceService (Service field 5):
+     *   MediaSourceService { MediaCodecType available_type = 1; AudioConfiguration audio_config = 2;
+     *                        bool available_while_in_call = 3; }
+     * Null when the head unit has none.
+     */
+    fun findMicService(response: ByteArray): AudioService? {
+        for (channel in Wire.allBytes(Wire.fields(response), 1)) {
+            val service = Wire.fields(channel)
+            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val source = Wire.fields(Wire.bytes(service, 5) ?: continue)
+            val f = Wire.fields(Wire.bytes(source, 2) ?: continue)
+            return AudioService(
+                serviceId = id,
+                streamType = 0,
+                codecType = Wire.varint(source, 1)?.toInt() ?: CODEC_PCM,
+                configs = listOf(
+                    AudioConfig(
+                        sampleRate = Wire.varint(f, 1)?.toInt() ?: 16_000,
+                        bits = Wire.varint(f, 2)?.toInt() ?: 16,
+                        channels = Wire.varint(f, 3)?.toInt() ?: 1,
+                    ),
+                ),
+            )
+        }
+        return null
+    }
+
+    /**
+     * The car's Bluetooth, from BluetoothService (Service field 6):
+     *   BluetoothService { string car_address = 1; repeated BluetoothPairingMethod methods = 2 [packed]; }
+     * Null when the car offers no pairing over the link.
+     */
+    class BluetoothService(val serviceId: Int, val carAddress: String, val pairingMethods: List<Int>)
+
+    /** A carmaker's own channel (service field 12), for its apps on the phone: GM's is "com.gm.vip". */
+    class VendorService(val serviceId: Int, val name: String)
+
+    fun findVendorServices(response: ByteArray): List<VendorService> =
+        Wire.allBytes(Wire.fields(response), 1).mapNotNull { channel ->
+            val service = Wire.fields(channel)
+            val id = Wire.varint(service, 1)?.toInt() ?: return@mapNotNull null
+            val fields = Wire.fields(Wire.bytes(service, 12) ?: return@mapNotNull null)
+            val name = Wire.bytes(fields, 1)?.let { String(it, Charsets.UTF_8) } ?: return@mapNotNull null
+            VendorService(id, name)
+        }
+
+    fun findBluetoothService(response: ByteArray): BluetoothService? {
+        for (channel in Wire.allBytes(Wire.fields(response), 1)) {
+            val service = Wire.fields(channel)
+            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val fields = Wire.fields(Wire.bytes(service, 6) ?: continue)
+            val address = Wire.bytes(fields, 1)?.let { String(it, Charsets.UTF_8) } ?: continue
+            // Packed as declared, though a car may send each method as its own varint.
+            val methods = fields.filter { it.number == 2 }.flatMap { f ->
+                f.bytes?.let(::packedVarints) ?: listOf(f.varint.toInt())
+            }
+            return BluetoothService(id, address, methods)
+        }
+        return null
+    }
+
+    const val STREAM_GUIDANCE = 1
+    const val STREAM_MEDIA = 3
+    const val CODEC_PCM = 1
+    const val CODEC_AAC_LC = 2
+    const val CODEC_AAC_LC_ADTS = 4
+
     private val STREAMS = mapOf(0 to "NONE", 1 to "GUIDANCE", 2 to "SYSTEM_AUDIO", 3 to "MEDIA", 4 to "TELEPHONY")
 
     private val RESOLUTIONS = mapOf(
@@ -106,30 +210,83 @@ object ServiceDiscovery {
     )
 
     /**
-     * The head unit's touchscreen, from InputSourceService (Service field 4):
-     *   InputSourceService { keycodes = 1; repeated TouchScreen touchscreen = 2; ... }
+     * The head unit's touchscreen and button set, from InputSourceService (Service field 4):
+     *   InputSourceService { repeated int32 keycodes_supported = 1 [packed=true];
+     *                         repeated TouchScreen touchscreen = 2; ... }
      *   TouchScreen { required int32 width = 1; required int32 height = 2; type = 3; }
      *
      * Touch coordinates arrive in this space (1258x708 on the 2018 Uconnect) and must be
-     * scaled to the projected video size before injection.
+     * scaled to the projected video size before injection. [keycodesSupported] is what the
+     * head unit says it will actually send over the Input channel as key events (steering-wheel
+     * buttons, etc.) - not every unit reports the same set, so it's kept for diagnostics and to
+     * know ahead of time whether a button like voice/PTT is even wired up on this hardware.
      */
-    class InputService(val serviceId: Int, val touchWidth: Int, val touchHeight: Int)
+    class InputService(
+        val serviceId: Int,
+        val touchWidth: Int,
+        val touchHeight: Int,
+        val keycodesSupported: List<Int> = emptyList(),
+        /** InputSourceService field 5: which screen this input belongs to, 0 for the main one. */
+        val displayId: Int = 0,
+    )
 
-    fun findInputService(response: ByteArray): InputService? {
+    /**
+     * The input for the screen Gearslip projects to ([displayId]). A head unit with two screens
+     * offers an input service for each: LIVI lists an empty one for its second screen first,
+     * and taking that one left every touch on the real touchscreen ignored.
+     */
+    fun findInputService(response: ByteArray, displayId: Int = 0): InputService? {
+        val inputs = inputServices(response)
+        return inputs.firstOrNull { it.displayId == displayId }
+            ?: inputs.firstOrNull { it.touchWidth > 0 && it.touchHeight > 0 }
+            ?: inputs.firstOrNull()
+    }
+
+    private fun inputServices(response: ByteArray): List<InputService> = buildList {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)
             val id = Wire.varint(service, 1)?.toInt() ?: continue
             val input = Wire.bytes(service, 4) ?: continue
-            val touch = Wire.bytes(Wire.fields(input), 2) ?: continue
-            val touchFields = Wire.fields(touch)
-            val width = Wire.varint(touchFields, 1)?.toInt() ?: continue
-            val height = Wire.varint(touchFields, 2)?.toInt() ?: continue
-            return InputService(id, width, height)
+            val inputFields = Wire.fields(input)
+            // A unit with only a knob and buttons has no touchscreen entry; it still has keys.
+            val touchFields = Wire.bytes(inputFields, 2)?.let { Wire.fields(it) }.orEmpty()
+            val width = Wire.varint(touchFields, 1)?.toInt() ?: 0
+            val height = Wire.varint(touchFields, 2)?.toInt() ?: 0
+            // Declared packed, but some units send each keycode as its own field.
+            val keycodes = inputFields.filter { it.number == 1 }.flatMap { f ->
+                f.bytes?.let(::packedVarints) ?: listOf(f.varint.toInt())
+            }
+            add(InputService(id, width, height, keycodes, Wire.varint(inputFields, 5)?.toInt() ?: 0))
         }
-        return null
     }
 
+    /** Decodes a `[packed=true]` repeated varint field's raw bytes into individual values. */
+    private fun packedVarints(data: ByteArray): List<Int> = buildList {
+        var pos = 0
+        while (pos < data.size) {
+            var result = 0L
+            var shift = 0
+            while (pos < data.size) {
+                val b = data[pos].toInt() and 0xFF
+                result = result or ((b and 0x7F).toLong() shl shift)
+                pos++
+                if (b and 0x80 == 0) break
+                shift += 7
+            }
+            add(result.toInt())
+        }
+    }
+
+    /**
+     * The main screen's video sink. A head unit with a second screen, such as LIVI with a
+     * cluster display, offers a sink for each; the one without a display id (0) is the main one.
+     */
     fun findVideoService(response: ByteArray): VideoService? {
+        val sinks = videoServices(response)
+        return sinks.firstOrNull { it.displayId == 0 } ?: sinks.firstOrNull()
+    }
+
+    private fun videoServices(response: ByteArray): List<VideoService> = buildList {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)
             val id = Wire.varint(service, 1)?.toInt() ?: continue
@@ -150,7 +307,31 @@ object ServiceDiscovery {
                     heightMargin = Wire.varint(f, 4)?.toInt() ?: 0,
                 )
             }
-            return VideoService(id, codecType, configs)
+            add(VideoService(id, codecType, configs, Wire.varint(sinkFields, 6)?.toInt() ?: 0))
+        }
+    }
+
+    /**
+     * The head unit's sensor feed, from SensorSourceService (Service field 2; field 5 is the car's mic):
+     *   SensorSourceService { repeated Sensor sensors = 1; }
+     *   Sensor { required SensorType sensor_type = 1; }
+     *
+     * Field numbers for what actually rides inside each SensorEvent once subscribed are not
+     * pinned down here - unlike video/audio/input, there's no independent source to check them
+     * against, so [CarSensors] shows the raw decode instead of trusting a guessed field map.
+     */
+    class SensorService(val serviceId: Int, val types: List<Int>)
+
+    fun findSensorService(response: ByteArray): SensorService? {
+        for (channel in Wire.allBytes(Wire.fields(response), 1)) {
+            val service = Wire.fields(channel)
+            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val sensorSource = Wire.bytes(service, 2) ?: continue
+            val types = Wire.allBytes(Wire.fields(sensorSource), 1).mapNotNull {
+                Wire.varint(Wire.fields(it), 1)?.toInt()
+            }
+            if (types.isEmpty()) continue
+            return SensorService(id, types)
         }
         return null
     }

gearslip/src/main/java/app/seb3thehacker/gearslip/SessionReport.kt

@@ -1,6 +1,7 @@
 package app.seb3thehacker.gearslip
 
 import android.content.Context
+import app.seb3thehacker.gearslip.stats.UsageStats
 import android.os.Build
 
 /**
@@ -23,16 +24,35 @@ object SessionReport {
         AUTH("authentication failed"),
         SERVICE_DISCOVERY("service discovery failed"),
         VIDEO("video stream failed"),
+        BYEBYE("head unit ended the session"),
         CRASH("app crash"),
         UNKNOWN("unclassified"),
     }
 
+    /**
+     * How far a session got, in the order a connection is built. The usage note's "Where
+     * connections fail" share sends the furthest one reached, so a failure says where it broke.
+     */
+    enum class Stage(val key: String) {
+        USB("usb"),             // the link opened; the car may have said nothing
+        VERSIONS("versions"),   // the car said which protocol it speaks
+        TLS("tls"),             // the secure link is up
+        ACCEPTED("accepted"),   // the car accepted the certificate
+        CHANNELS("channels"),   // the car listed its channels and said who it is
+        VIDEO("video"),         // the car's screen is set up for Gearslip
+        STREAMING("streaming"), // video frames are reaching the car
+    }
+
     private var appVersion = "?"
     private var appCode = 0L
 
     @Volatile private var startedAt = 0L
     @Volatile var category = Category.NONE; private set
     @Volatile private var failure = ""
+    @Volatile var stage = Stage.USB; private set
+    /** What the car or the phone said when it broke: a TLS alert, an auth status, a ByeBye reason, an errno. */
+    @Volatile private var failCode = ""
+    @Volatile private var failedAfter = 0L
     @Volatile private var protocolVersion = ""
     @Volatile private var certSource = ""
     @Volatile private var certIssuer = ""
@@ -47,41 +67,114 @@ object SessionReport {
     @Volatile private var lastState = ""
     private var printed = false
 
+    private var appContext: Context? = null
+
     fun init(context: Context) {
+        appContext = context.applicationContext
         val info = runCatching { context.packageManager.getPackageInfo(context.packageName, 0) }.getOrNull()
         appVersion = info?.versionName ?: "?"
         appCode = info?.longVersionCode ?: 0
     }
 
-    fun begin() {
+    /** How this drive reached the car, and how its music did: "usb" or "wireless", "usb" or "bluetooth". */
+    @Volatile var link = ""; private set
+    @Volatile var audioMode = ""; private set
+
+    fun begin(wireless: Boolean) {
         startedAt = System.currentTimeMillis()
+        link = if (wireless) "wireless" else "usb"
+        audioMode = if (app.seb3thehacker.gearslip.car.CarSettings.pipeAudio.value) "usb" else "bluetooth"
         category = Category.NONE
         failure = ""; protocolVersion = ""; certSource = ""; certIssuer = ""
+        stage = Stage.USB; failCode = ""; failedAfter = 0
         tlsProtocol = ""; tlsCipher = ""; authStatus = null
+        headUnitInfo = null
+        carScreen = ""; carDpi = 0
         headUnit = ""; profile = ""; video = ""; lastStream = ""; lastState = ""
         printed = false
     }
 
-    fun protocolVersion(major: Int, minor: Int) { protocolVersion = "$major.$minor" }
+    /** Moves the session's furthest stage on; never back. */
+    private fun reached(next: Stage) { if (next > stage) stage = next }
+
+    fun protocolVersion(major: Int, minor: Int) { protocolVersion = "$major.$minor"; reached(Stage.VERSIONS) }
     fun certificate(source: String, issuer: String) { certSource = source; certIssuer = issuer }
-    fun tls(protocol: String, cipher: String) { tlsProtocol = protocol; tlsCipher = cipher }
-    fun auth(status: Int) { authStatus = status }
+    fun tls(protocol: String, cipher: String) { tlsProtocol = protocol; tlsCipher = cipher; reached(Stage.TLS) }
+    fun auth(status: Int) { authStatus = status; if (status == 0) reached(Stage.ACCEPTED) }
     fun headUnit(info: String) { headUnit = info }
+
+    /** Who the car said it is, for the opt-in usage note; null until service discovery. */
+    @Volatile var headUnitInfo: ServiceDiscovery.HeadUnitInfo? = null
+        set(value) { field = value; if (value != null) reached(Stage.CHANNELS) }
+
+    /** The car screen's usable size once its margins are cropped, and its density; blank before video starts. */
+    @Volatile var carScreen = ""; private set
+    @Volatile var carDpi = 0; private set
+    fun carScreen(size: String, dpi: Int) { carScreen = size; carDpi = dpi; reached(Stage.VIDEO) }
     fun profile(name: String?) { profile = name ?: "none matched" }
     fun video(summary: String) { video = summary }
     fun audio(summary: String) { audio = summary }
-    fun stream(summary: String) { lastStream = summary }
+    fun stream(summary: String) { lastStream = summary; reached(Stage.STREAMING) }
 
-    /** Records the first failure only: later ones are usually fallout from it. */
-    fun fail(category: Category, detail: String, state: String = "") {
+    /**
+     * Records the first failure only: later ones are usually fallout from it. [code] is the short
+     * thing the car or the phone said, like "auth -3" or "bye 1", for the usage note.
+     */
+    fun fail(category: Category, detail: String, state: String = "", code: String = "") {
         if (this.category != Category.NONE) return
         this.category = category
         failure = detail
         lastState = state
+        failCode = code
+        failedAfter = if (startedAt == 0L) 0 else (System.currentTimeMillis() - startedAt) / 1000
     }
 
     fun fail(category: Category, detail: String, t: Throwable, state: String = "") =
-        fail(category, "$detail (${GearslipLog.rootCause(t)})", state)
+        fail(category, "$detail (${GearslipLog.rootCause(t)})", state, codeOf(t))
+
+    /**
+     * A short code from an exception, never its whole message: the TLS alert's name, the errno
+     * of a USB failure, or else the exception's class.
+     */
+    private fun codeOf(t: Throwable): String {
+        var root = t
+        while (root.cause != null && root.cause !== root) root = root.cause!!
+        val text = "${t.message} ${root.message}"
+        Regex("(?i)alert[ _:]*\\(?([a-z_ ]{3,40}?)\\)?(?:\\s|$|[,;.])").find(text)?.let {
+            return "alert ${it.groupValues[1].trim().lowercase().replace(' ', '_')}"
+        }
+        Regex("\\b(E[A-Z]{2,12})\\b").find(text)?.let { return it.groupValues[1] }
+        return root.javaClass.simpleName.take(40)
+    }
+
+    /**
+     * One session for the usage note's "Where connections fail" share: how far it got, how and
+     * when it ended, and with which kind of certificate. Counts and codes only, nothing personal.
+     */
+    fun sessionNote(): org.json.JSONObject {
+        val seconds = if (startedAt == 0L) 0 else (System.currentTimeMillis() - startedAt) / 1000
+        val source = certSource.lowercase()
+        return org.json.JSONObject()
+            .put("stage", stage.key)
+            .put("ended", category.name.lowercase())
+            .put("code", failCode)
+            .put("failed_at", if (category == Category.NONE) 0 else rounded(failedAfter))
+            .put("seconds", rounded(seconds))
+            .put("cert", when {
+                "imported" in source -> "imported"
+                "downloaded" in source -> "downloaded"
+                "self" in source -> "self-signed"
+                source.isEmpty() -> ""
+                else -> "other"
+            })
+    }
+
+    /** Seconds rounded so a drive's length can't be matched to anything: 5 s, then minutes, then 5 minutes. */
+    private fun rounded(s: Long): Long = when {
+        s < 60 -> (s + 2) / 5 * 5
+        s < 3600 -> (s + 30) / 60 * 60
+        else -> (s + 150) / 300 * 300
+    }
 
     /** The report as plain text, for the log file and for anything that gets sent. */
     fun render(): String {
@@ -120,6 +213,25 @@ object SessionReport {
         if (printed || startedAt == 0L) return
         printed = true
         render().lines().forEach { GearslipLog.i(it) }
+        appContext?.let { context ->
+            // Video started means the car showed Gearslip: that's a working car, and unplugging or
+            // switching the car off at the end shows up as a USB or ByeBye "failure" that isn't one.
+            val reached = carScreen.isNotEmpty()
+            val outcome = when {
+                reached && category in setOf(Category.NONE, Category.USB, Category.BYEBYE) -> "connected"
+                reached -> "connected, then ${category.label}"
+                category == Category.NONE -> "ended before video"
+                else -> category.label
+            }
+            runCatching {
+                UsageStats.recordSession(context, headUnitInfo, protocolVersion, outcome, carScreen, carDpi, sessionNote(), link, audioMode)
+            }
+            if (outcome == "connected") runCatching {
+                app.seb3thehacker.gearslip.stats.WorkedPrompt.onDriveWorked(context, headUnitInfo, protocolVersion, carScreen, carDpi)
+                app.seb3thehacker.gearslip.ui.DonatePrompt.onDriveWorked(context)
+            }
+            runCatching { app.seb3thehacker.gearslip.update.UpdateChecker.onDriveEnded(context) }
+        }
         GearslipLog.flush()
     }
 

gearslip/src/main/java/app/seb3thehacker/gearslip/SessionStatus.kt

@@ -20,7 +20,7 @@ object SessionStatus {
         Snapshot(
             Phase.IDLE,
             "Not connected",
-            "Plug the phone into the car's USB port. Gearslip opens by itself when the head unit connects.",
+            "Plug into the car's USB port, or connect wirelessly. Gearslip opens by itself when the car answers.",
         ),
     )
 

gearslip/src/main/java/app/seb3thehacker/gearslip/VideoSource.kt

@@ -23,6 +23,8 @@ class VideoSource(
     private val height: Int,
     private val frameRate: Int,
     private val mode: Mode = Mode.TEST_CARD,
+    /** Over Wi-Fi: a fraction of the cable bitrate, so the link keeps up and sound isn't starved. */
+    private val wireless: Boolean = false,
     private val onCodecConfig: (ByteArray) -> Unit,
     private val onFrame: (data: ByteArray, presentationTimeUs: Long, keyFrame: Boolean) -> Unit,
 ) {
@@ -45,7 +47,11 @@ class VideoSource(
     private var frameIndex = 0L
 
     fun start() {
-        val format = MediaFormat.createVideoFormat(MIME, width, height).apply {
+        val level = levelFor(width, height, frameRate)
+        val bitRate = defaultBitRate(width, height, frameRate, level).let {
+            if (wireless) (it * WIRELESS_SHARE).toInt().coerceAtMost(WIRELESS_MAX_BIT_RATE) else it
+        }
+        fun format(tuned: Boolean) = MediaFormat.createVideoFormat(MIME, width, height).apply {
             setInteger(
                 MediaFormat.KEY_COLOR_FORMAT,
                 if (mode == Mode.SURFACE) {
@@ -54,21 +60,50 @@ class VideoSource(
                     MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420Flexible
                 },
             )
-            setInteger(MediaFormat.KEY_BIT_RATE, 2_000_000)
+            setInteger(MediaFormat.KEY_BIT_RATE, bitRate)
             setInteger(MediaFormat.KEY_FRAME_RATE, frameRate)
-            setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 1)
+            // Drops already ask for a fresh keyframe, so a long interval costs nothing in recovery
+            // and spares the link a big frame every second.
+            setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, I_FRAME_INTERVAL_S)
+            if (mode == Mode.SURFACE) {
+                // A surface encoder only makes a frame when the screen changes, and many decoders
+                // show a frame only once the next one arrives. So the last change before the
+                // screen goes still (a menu closing) sat in the car's decoder until something
+                // else moved. Repeating the last frame after a short pause pushes it through;
+                // a repeat of an unchanged screen costs a few bytes. scrcpy does the same.
+                setLong(MediaFormat.KEY_REPEAT_PREVIOUS_FRAME_AFTER, REPEAT_AFTER_US)
+                // An app that draws nonstop (a moving map) renders at the phone's refresh rate,
+                // faster than the car acks. Every extra frame queued inside the encoder, and the
+                // car's screen fell 25 seconds behind. Capping the input drops the extras before
+                // they're encoded, so the car always gets the newest frame.
+                setFloat(MediaFormat.KEY_MAX_FPS_TO_ENCODER, frameRate.toFloat())
+            }
             setInteger(MediaFormat.KEY_PROFILE, MediaCodecInfo.CodecProfileLevel.AVCProfileBaseline)
-            setInteger(MediaFormat.KEY_LEVEL, MediaCodecInfo.CodecProfileLevel.AVCLevel31)
+            setInteger(MediaFormat.KEY_LEVEL, level.codecLevel)
+            if (tuned) {
+                // Hints only: a car screen wants each frame now, not the best frame a moment later.
+                setInteger(MediaFormat.KEY_BITRATE_MODE, MediaCodecInfo.EncoderCapabilities.BITRATE_MODE_VBR)
+                setInteger(MediaFormat.KEY_PRIORITY, 0)
+                setInteger(MediaFormat.KEY_LATENCY, 1)
+            }
         }
 
-        val encoder = MediaCodec.createEncoderByType(MIME)
-        encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE)
+        var encoder = MediaCodec.createEncoderByType(MIME)
+        try {
+            encoder.configure(format(tuned = true), null, null, MediaCodec.CONFIGURE_FLAG_ENCODE)
+        } catch (e: Exception) {
+            // Some encoders refuse a hint they don't know. The plain format is what always worked.
+            log.w("encoder refused the tuned format (${e.message}) - using the plain one")
+            encoder.release()
+            encoder = MediaCodec.createEncoderByType(MIME)
+            encoder.configure(format(tuned = false), null, null, MediaCodec.CONFIGURE_FLAG_ENCODE)
+        }
         if (mode == Mode.SURFACE) inputSurface = encoder.createInputSurface()
         encoder.start()
         codec = encoder
         running = true
 
-        log.i("encoder started: ${width}x$height @ ${frameRate}fps, H.264 Baseline, mode=$mode")
+        log.i("encoder started: ${width}x$height @ ${frameRate}fps, ${bitRate / 1000} kbps${if (wireless) " (wireless)" else ""}, H.264 Baseline level ${level.label}, mode=$mode")
 
         worker = Thread {
             runCatching { pump(encoder) }
@@ -123,7 +158,10 @@ class VideoSource(
                 frameIndex++
             }
 
-            var outIndex = encoder.dequeueOutputBuffer(info, TIMEOUT_US)
+            // A surface-fed encoder has nothing to do between frames, so block until one is ready
+            // instead of sleeping a fixed time: less delay on screen, fewer wakeups for the CPU.
+            val wait = if (mode == Mode.SURFACE) SURFACE_TIMEOUT_US else TIMEOUT_US
+            var outIndex = encoder.dequeueOutputBuffer(info, wait)
             while (outIndex >= 0) {
                 val buffer = encoder.getOutputBuffer(outIndex)
                 if (buffer != null && info.size > 0) {
@@ -144,7 +182,7 @@ class VideoSource(
                 outIndex = encoder.dequeueOutputBuffer(info, 0)
             }
 
-            Thread.sleep(maxOf(1L, frameIntervalUs / 2000))
+            if (mode != Mode.SURFACE) Thread.sleep(maxOf(1L, frameIntervalUs / 2000))
         }
     }
 
@@ -188,6 +226,52 @@ class VideoSource(
     private companion object {
         const val MIME = MediaFormat.MIMETYPE_VIDEO_AVC
         const val TIMEOUT_US = 10_000L
+        const val SURFACE_TIMEOUT_US = 100_000L
+
+        /**
+         * 800x480 at 30fps gets 8 Mbps: about the most that size can show, enough that a moving
+         * video in the browser stays sharp. Bigger screens get more, but less than in proportion,
+         * since large frames compress better: bitrate grows with pixels^0.75. 60fps gets 1.5x,
+         * because frames that close together are mostly alike.
+         */
+        const val BASE_BIT_RATE = 8_000_000.0
+        const val BASE_PIXELS = 800.0 * 480
+        /** No car's decoder is asked for more than this, whatever its level allows. */
+        const val MAX_BIT_RATE = 25_000_000
+
+        /**
+         * The H.264 levels a car screen can need, smallest first: macroblocks a second each
+         * decodes, and the Baseline bitrate it must handle. The encoder declares the smallest
+         * that fits, and the bitrate stays within it, so a car decoder isn't asked for more than
+         * the level it was told about.
+         */
+        enum class Level(val label: String, val codecLevel: Int, val macroblocksPerSecond: Int, val maxBitRate: Int) {
+            L31("3.1", MediaCodecInfo.CodecProfileLevel.AVCLevel31, 108_000, 14_000_000),
+            L32("3.2", MediaCodecInfo.CodecProfileLevel.AVCLevel32, 216_000, 20_000_000),
+            L4("4", MediaCodecInfo.CodecProfileLevel.AVCLevel4, 245_760, 20_000_000),
+            L42("4.2", MediaCodecInfo.CodecProfileLevel.AVCLevel42, 522_240, 50_000_000),
+        }
+
+        fun levelFor(width: Int, height: Int, frameRate: Int): Level {
+            val perSecond = ((width + 15) / 16) * ((height + 15) / 16) * frameRate
+            return Level.entries.firstOrNull { perSecond <= it.macroblocksPerSecond } ?: Level.L42
+        }
+
+        fun defaultBitRate(width: Int, height: Int, frameRate: Int, level: Level): Int {
+            val size = Math.pow(width.toDouble() * height / BASE_PIXELS, 0.75)
+            val rate = if (frameRate > 30) 1.5 else 1.0
+            return (BASE_BIT_RATE * size * rate).toInt().coerceAtMost(minOf(level.maxBitRate, MAX_BIT_RATE))
+        }
+        /**
+         * A car's Wi-Fi is shared, noisy and far slower than its nominal rate, and the sound rides
+         * the same link behind the video. Real Android Auto sends a few Mbps wirelessly; at the
+         * cable rate (15-20 Mbps for 720p) a laptop hotspot fell seconds behind and the music
+         * cut in and out. 720p30 comes out near 5.4 Mbps.
+         */
+        const val WIRELESS_SHARE = 0.35
+        const val WIRELESS_MAX_BIT_RATE = 8_000_000
+        const val I_FRAME_INTERVAL_S = 5
+        private const val REPEAT_AFTER_US = 100_000L
 
         /** (Y, Cb, Cr) - white, yellow, cyan, green, magenta, red, blue. */
         val BAR_COLOURS = listOf(

gearslip/src/main/java/app/seb3thehacker/gearslip/audio/AacEncoder.kt

@@ -0,0 +1,94 @@
+package app.seb3thehacker.gearslip.audio
+
+import android.media.MediaCodec
+import android.media.MediaCodecInfo
+import android.media.MediaFormat
+
+/**
+ * Turns captured PCM into AAC-LC for a car whose music channel takes nothing else. Cars that
+ * offer PCM never get here: AAC costs a little delay and quality, and every car that works today
+ * is a PCM car.
+ *
+ * Android's encoder hands back raw access units, which is what AUDIO_AAC_LC expects. For
+ * AUDIO_AAC_LC_ADTS each unit gets the 7-byte ADTS header in front, so the car can find the
+ * frame edges itself. The encoder's first output is its configuration, not audio, and is skipped.
+ */
+internal class AacEncoder(private val sampleRate: Int, private val channels: Int, private val adts: Boolean) {
+
+    private val codec: MediaCodec = MediaCodec.createEncoderByType(MediaFormat.MIMETYPE_AUDIO_AAC).apply {
+        val format = MediaFormat.createAudioFormat(MediaFormat.MIMETYPE_AUDIO_AAC, sampleRate, channels).apply {
+            setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectLC)
+            setInteger(MediaFormat.KEY_BIT_RATE, if (channels == 1) 96_000 else 192_000)
+            setInteger(MediaFormat.KEY_MAX_INPUT_SIZE, 16 * 1024)
+        }
+        configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE)
+        start()
+    }
+    private val info = MediaCodec.BufferInfo()
+    private var samplesIn = 0L
+
+    /** Encodes [size] bytes of 16-bit PCM and returns the AAC frames that came out, oldest first. */
+    fun encode(pcm: ByteArray, size: Int): List<ByteArray> {
+        var offset = 0
+        val out = ArrayList<ByteArray>()
+        while (offset < size) {
+            val index = codec.dequeueInputBuffer(INPUT_WAIT_US)
+            if (index < 0) {
+                drain(out)
+                continue
+            }
+            val buffer = codec.getInputBuffer(index) ?: continue
+            val n = minOf(buffer.remaining(), size - offset)
+            buffer.put(pcm, offset, n)
+            val presentationUs = samplesIn * 1_000_000L / sampleRate
+            codec.queueInputBuffer(index, 0, n, presentationUs, 0)
+            samplesIn += n / (2 * channels)
+            offset += n
+            drain(out)
+        }
+        return out
+    }
+
+    private fun drain(out: MutableList<ByteArray>) {
+        while (true) {
+            val index = codec.dequeueOutputBuffer(info, 0)
+            if (index < 0) return
+            if (info.flags and MediaCodec.BUFFER_FLAG_CODEC_CONFIG == 0 && info.size > 0) {
+                val buffer = codec.getOutputBuffer(index)
+                if (buffer != null) {
+                    val frame = ByteArray(info.size)
+                    buffer.position(info.offset)
+                    buffer.get(frame)
+                    out.add(if (adts) adtsHeader(frame.size) + frame else frame)
+                }
+            }
+            codec.releaseOutputBuffer(index, false)
+        }
+    }
+
+    /** ADTS for one AAC-LC frame: sync word, no CRC, and the frame's length including this header. */
+    private fun adtsHeader(payload: Int): ByteArray {
+        val length = payload + 7
+        val freq = FREQUENCIES.indexOf(sampleRate).let { if (it < 0) 3 else it }
+        val profile = 1 // AAC-LC is object type 2, written as type minus one
+        return byteArrayOf(
+            0xFF.toByte(),
+            0xF1.toByte(),
+            ((profile shl 6) or (freq shl 2) or (channels shr 2)).toByte(),
+            (((channels and 3) shl 6) or (length shr 11)).toByte(),
+            ((length shr 3) and 0xFF).toByte(),
+            (((length and 7) shl 5) or 0x1F).toByte(),
+            0xFC.toByte(),
+        )
+    }
+
+    fun release() {
+        runCatching { codec.stop() }
+        runCatching { codec.release() }
+    }
+
+    private companion object {
+        const val INPUT_WAIT_US = 10_000L
+        val FREQUENCIES = listOf(96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000, 12000, 11025, 8000, 7350)
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/audio/AudioCaptureService.kt

@@ -7,6 +7,7 @@ import android.app.PendingIntent
 import android.app.Service
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.content.pm.ServiceInfo
 import android.media.AudioAttributes
 import android.media.AudioFormat
@@ -15,6 +16,7 @@ import android.media.AudioRecord
 import android.media.projection.MediaProjection
 import android.media.projection.MediaProjectionManager
 import android.os.IBinder
+import android.os.Process
 import app.seb3thehacker.gearslip.GearslipLog
 import kotlin.math.abs
 
@@ -83,7 +85,13 @@ class AudioCaptureService : Service() {
             return START_NOT_STICKY
         }
 
-        startForeground(NOTIFICATION_ID, notification(), ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION)
+        // Android silences the microphone for apps in the background unless a running service
+        // claims it. Claiming it here lets voice replies hear the driver with the phone locked.
+        // Without the permission, claiming it would crash, so it's left off.
+        val micGranted = checkSelfPermission(android.Manifest.permission.RECORD_AUDIO) == PackageManager.PERMISSION_GRANTED
+        val type = ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION or
+            (if (micGranted) ServiceInfo.FOREGROUND_SERVICE_TYPE_MICROPHONE else 0)
+        startForeground(NOTIFICATION_ID, notification(), type)
         ScreenShareGuard.lift(this)
         projection = try {
             getSystemService(MediaProjectionManager::class.java).getMediaProjection(resultCode, data)
@@ -129,7 +137,7 @@ class AudioCaptureService : Service() {
             AudioRecord.Builder()
                 .setAudioPlaybackCaptureConfig(config)
                 .setAudioFormat(format)
-                .setBufferSizeInBytes(maxOf(minimum, CHUNK_BYTES * 4))
+                .setBufferSizeInBytes(maxOf(minimum, CHUNK_BYTES * BUFFER_CHUNKS))
                 .build()
         } catch (t: Throwable) {
             GearslipLog.e("audio: could not set up playback capture", t)
@@ -140,6 +148,9 @@ class AudioCaptureService : Service() {
 
         reading = true
         thread = Thread({
+            // A busy phone (a map app drawing, the video encoder) would otherwise starve this
+            // loop, and the car hears every late read as a skip.
+            Process.setThreadPriority(Process.THREAD_PRIORITY_URGENT_AUDIO)
             val buffer = ByteArray(CHUNK_BYTES)
             var peak = 0
             var heardAt = System.currentTimeMillis()
@@ -233,6 +244,8 @@ class AudioCaptureService : Service() {
 
         /** About 21 ms of 48 kHz stereo: small enough for lip-sync, big enough not to flood the link. */
         private const val CHUNK_BYTES = 4096
+        /** About half a second: room to wait out a slow ack from the car without losing sound. */
+        private const val BUFFER_CHUNKS = 24
         private const val LEVEL_LOG_MS = 3_000L
         private const val SILENCE_MS = 5_000L
 

gearslip/src/main/java/app/seb3thehacker/gearslip/audio/AudioLink.kt

@@ -22,6 +22,15 @@ class AudioLink(
     private val service: ServiceDiscovery.AudioService,
     private val sendOnChannel: (messageId: Int, body: ByteArray) -> Unit,
     private val sendControl: (messageId: Int, body: ByteArray) -> Unit,
+    /** Log name: "audio" for the media sink, "guidance" for the directions sink. */
+    private val tag: String = "audio",
+    private val sessionId: Int = SESSION_ID,
+    /** Media asks the car for focus; directions just start, and the car ducks music under them. */
+    private val asksFocus: Boolean = true,
+    private val onReady: (AudioLink) -> Unit = { CarAudio.attach(it) },
+    private val onClose: (AudioLink) -> Unit = { CarAudio.detach(it) },
+    /** The car took the sound back after giving it, as when the driver switches to the radio. */
+    private val onTakenBack: () -> Unit = {},
 ) : CarAudio.Link {
 
     private var configIndex = 0
@@ -33,10 +42,15 @@ class AudioLink(
     // The Uconnect asks for 4 on its video channel; assume the same until its Config says otherwise.
     @Volatile private var maxUnacked = 4
     @Volatile private var lastAckAt = 0L
+    private var stalls = 0
     private var chunks = 0
     private var bytes = 0L
     private var dropped = 0
     @Volatile private var configTimer: Thread? = null
+    private val ackLock = Object()
+    /** Only for a sink that takes AAC and nothing else; PCM sinks get the capture as it is. */
+    @Volatile private var aac: AacEncoder? = null
+    private val aacSink get() = service.codecType == ServiceDiscovery.CODEC_AAC_LC || service.codecType == ServiceDiscovery.CODEC_AAC_LC_ADTS
 
     private val config get() = service.configs.getOrNull(configIndex) ?: service.configs.firstOrNull()
     override val sampleRate get() = config?.sampleRate ?: 48_000
@@ -45,28 +59,29 @@ class AudioLink(
     val channelId get() = service.serviceId
 
     fun opened(status: Int) {
-        GearslipLog.i("audio: <- ChannelOpenResponse (media audio): status=$status")
+        GearslipLog.i("$tag: <- ChannelOpenResponse: status=$status")
         if (status != 0) {
-            GearslipLog.w("audio: the head unit refused the media audio channel (status $status)")
+            GearslipLog.w("$tag: the head unit refused the $tag channel (status $status)")
             return
         }
-        // AVChannelSetupRequest { required uint32 config_index = 1 }. This field is an index into
-        // the sink's own audio_configs, not a codec id - sending the codec type asks for a config
-        // the sink does not have, and it answers with a status that never reaches READY.
-        sendOnChannel(MSG_SETUP, Protobuf.varintField(1, 0L))
-        GearslipLog.i("audio: -> Setup(config_index=0) on channel ${service.serviceId}, codec ${service.codecName}")
+        // Setup { required MediaCodecType type = 1 }: the codec the car advertised for this sink
+        // (aasdk's current protos, and LIVI reads it as the codec). Gearslip used to send 0 here,
+        // read from an older proto as a config index; 0 is no codec at all, and the 2024 VW
+        // answered UNEXPECTED_MESSAGE (id 255), never acked a chunk and played nothing.
+        sendOnChannel(MSG_SETUP, Protobuf.varintField(1, service.codecType.toLong()))
+        GearslipLog.i("$tag: -> Setup(codec=${service.codecName}) on channel ${service.serviceId}")
         armConfigFallback()
     }
 
     /**
-     * The 2018 Uconnect answers our Setup with a two-byte message we cannot identify (id 255, no
-     * body) rather than the AVChannelSetupResponse the video channel gets, so the sink never
-     * reaches READY and no audio is ever sent.
+     * The 2018 Uconnect, a Dacia ULC 4.5 and the 2024 VW answered the old Setup (codec 0) with
+     * UNEXPECTED_MESSAGE (id 255, no body) rather than a Config, so the sink never reached READY.
+     * [MSG_SETUP_ANSWER] still takes that as the go-ahead, in case a car rejects the real codec too.
      *
-     * Service discovery already told us everything that message would have: the sink is PCM at
-     * 48000Hz stereo and it has exactly one configuration. So rather than wait forever for a
-     * message that is not coming, assume the advertised configuration and carry on. If that guess
-     * is wrong the head unit simply will not ack, which the write path already reports.
+     * Service discovery already told us everything a Config would have: the sink's rate, channels
+     * and its one configuration. So for a car that answers nothing at all, wait a moment and then
+     * assume the advertised configuration. If that guess is wrong the head unit simply will not
+     * ack, which the write path already reports.
      */
     private fun armConfigFallback() {
         val timer = Thread({
@@ -75,19 +90,25 @@ class AudioLink(
             } catch (e: InterruptedException) {
                 return@Thread
             }
-            if (ready) return@Thread
-            GearslipLog.w(
-                "audio: no usable Config after ${CONFIG_WAIT_MS}ms - falling back to the sink the " +
-                    "head unit advertised (${sampleRate}Hz x$channels, config_index=0, max_unacked=$maxUnacked)",
-            )
-            configIndex = 0
-            ready = true
-            CarAudio.attach(this)
+            useAdvertisedSink("no usable Config after ${CONFIG_WAIT_MS}ms")
         }, "gearslip-audio-config").apply { isDaemon = true }
         configTimer = timer
         timer.start()
     }
 
+    @Synchronized
+    private fun useAdvertisedSink(why: String) {
+        if (ready) return
+        configTimer?.interrupt()
+        GearslipLog.i(
+            "$tag: $why - using the sink the head unit advertised " +
+                "(${sampleRate}Hz x$channels, config_index=0, max_unacked=$maxUnacked)",
+        )
+        configIndex = 0
+        ready = true
+        onReady(this)
+    }
+
     fun onMessage(messageId: Int, body: ByteArray) {
         when (messageId) {
             MSG_CHANNEL_OPEN_RESPONSE -> opened(Protobuf.readInt32Field(body, 1) ?: 0)
@@ -97,17 +118,17 @@ class AudioLink(
                 val status = Wire.varint(fields, 1)?.toInt()
                 val window = Wire.varint(fields, 2)?.toInt()
                 val indices = fields.filter { it.number == 3 && it.wireType == 0 }.map { it.varint.toInt() }
-                GearslipLog.i("audio: <- Config status=$status max_unacked=$window indices=$indices")
+                GearslipLog.i("$tag: <- Config status=$status max_unacked=$window indices=$indices")
                 if (window != null) maxUnacked = maxOf(1, window)
                 configIndex = indices.firstOrNull() ?: 0
                 if (status == STATUS_READY) {
                     configTimer?.interrupt()
                     ready = true
-                    GearslipLog.i("audio: sink ready - ${sampleRate}Hz x$channels ${config?.bits}bit")
-                    CarAudio.attach(this)
+                    GearslipLog.i("$tag: sink ready - ${sampleRate}Hz x$channels ${config?.bits}bit")
+                    onReady(this)
                 } else {
                     GearslipLog.w(
-                        "audio: the sink is not ready (status=$status, 1=WAIT 2=READY) - " +
+                        "$tag: the sink is not ready (status=$status, 1=WAIT 2=READY) - " +
                             "nothing will be sent until it is",
                     )
                 }
@@ -115,13 +136,18 @@ class AudioLink(
 
             MSG_ACK -> {
                 val acked = Wire.varint(Wire.fields(body), 2)?.toInt() ?: 1
-                inFlight = maxOf(0, inFlight - maxOf(1, acked))
-                lastAckAt = System.currentTimeMillis()
+                synchronized(ackLock) {
+                    inFlight = maxOf(0, inFlight - maxOf(1, acked))
+                    lastAckAt = System.currentTimeMillis()
+                    ackLock.notifyAll()
+                }
             }
 
-            // Whatever the head unit answers Setup with, we need its bytes to identify it.
-            else -> {
-                GearslipLog.i("audio: <- unhandled message id=$messageId (${body.size} bytes)")
+            // Whatever else the head unit answers Setup with, we need its bytes to identify it.
+            else -> if (messageId == MSG_SETUP_ANSWER && body.isEmpty()) {
+                useAdvertisedSink("<- empty Setup answer (id $messageId)")
+            } else {
+                GearslipLog.i("$tag: <- unhandled message id=$messageId (${body.size} bytes)")
                 GearslipLog.hex("   audio msg", body, limit = 64)
             }
         }
@@ -134,17 +160,21 @@ class AudioLink(
      */
     fun onFocus(state: Int) {
         val name = FOCUS_STATES[state] ?: "unknown($state)"
-        GearslipLog.i("audio: <- AudioFocusResponse state=$name")
-        focusGranted = state == FOCUS_STATE_GAIN || state == FOCUS_STATE_GAIN_TRANSIENT
+        GearslipLog.i("$tag: <- AudioFocusResponse state=$name")
+        val had = focusGranted
+        focusGranted = state == FOCUS_STATE_GAIN || state == FOCUS_STATE_GAIN_TRANSIENT ||
+            state == FOCUS_STATE_GAIN_MEDIA_ONLY
         if (focusGranted) startStream() else stop()
+        // A ducking request leaves the music playing; a loss means another source has the speakers.
+        if (had && (state == FOCUS_STATE_LOSS || state == FOCUS_STATE_LOSS_TRANSIENT)) onTakenBack()
     }
 
     override fun start() {
         if (!ready || started) return
-        if (!focusRequested) {
+        if (asksFocus && !focusRequested) {
             focusRequested = true
             sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_GAIN.toLong()))
-            GearslipLog.i("audio: -> AudioFocusRequest(GAIN); waiting for the head unit to hand the sink over")
+            GearslipLog.i("$tag: -> AudioFocusRequest(GAIN); waiting for the head unit to hand the sink over")
         }
         // Some head units grant the sink silently and never answer. Do not let that be the end of
         // it: start anyway, and let the acks say whether anything is being taken.
@@ -155,58 +185,98 @@ class AudioLink(
         if (!ready || started) return
         sendOnChannel(
             MSG_START,
-            Protobuf.varintField(1, SESSION_ID.toLong()) + Protobuf.varintField(2, configIndex.toLong()),
+            Protobuf.varintField(1, sessionId.toLong()) + Protobuf.varintField(2, configIndex.toLong()),
         )
         inFlight = 0
         lastAckAt = System.currentTimeMillis()
+        if (aacSink && aac == null) {
+            aac = runCatching { AacEncoder(sampleRate, channels, adts = service.codecType == ServiceDiscovery.CODEC_AAC_LC_ADTS) }
+                .onSuccess { GearslipLog.i("$tag: the car takes ${service.codecName} only - encoding to AAC") }
+                .onFailure { GearslipLog.e("$tag: couldn't start the AAC encoder", it) }
+                .getOrNull()
+        }
         started = true
-        GearslipLog.i("audio: -> Start(session=$SESSION_ID, config=$configIndex) - streaming ${sampleRate}Hz x$channels")
+        GearslipLog.i("$tag: -> Start(session=$sessionId, config=$configIndex) - streaming ${sampleRate}Hz x$channels")
     }
 
     override fun stop() {
         if (!started) return
         started = false
+        synchronized(ackLock) { ackLock.notifyAll() }
         runCatching {
-            sendOnChannel(MSG_STOP, Protobuf.varintField(1, SESSION_ID.toLong()))
+            sendOnChannel(MSG_STOP, Protobuf.varintField(1, sessionId.toLong()))
             if (focusRequested) sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_RELEASE.toLong()))
         }
         focusRequested = false
         focusGranted = false
-        GearslipLog.i("audio: -> Stop, AudioFocusRequest(RELEASE) after $chunks chunks / $bytes bytes")
+        aac?.release()
+        aac = null
+        GearslipLog.i("$tag: -> Stop, AudioFocusRequest(RELEASE) after $chunks chunks / $bytes bytes")
         chunks = 0
         bytes = 0
     }
 
     override fun write(pcm: ByteArray, size: Int) {
         if (!started) return
-        if (inFlight >= maxUnacked) {
-            // A lost ack must not silence the stream for good; after a stall assume the window cleared.
-            if (System.currentTimeMillis() - lastAckAt > STALL_MS) {
-                GearslipLog.w("audio: no ack for ${STALL_MS}ms with $inFlight in flight - reopening the window")
-                inFlight = 0
-            } else {
-                dropped++
-                return
+        val encoder = aac
+        if (encoder == null) {
+            send(pcm.copyOf(size))
+            return
+        }
+        val frames = try {
+            encoder.encode(pcm, size)
+        } catch (e: Exception) {
+            // A codec that dies mid-drive leaves the car silent, as it was before AAC; log it once.
+            GearslipLog.e("$tag: AAC encoding failed - no more audio this drive", e)
+            aac = null
+            started = false
+            return
+        }
+        frames.forEach(::send)
+    }
+
+    /** One Data message, once the car has room for it. */
+    private fun send(payload: ByteArray) {
+        // Wait for the car to catch up rather than throw the chunk away: a dropped chunk is a gap
+        // the driver hears, while a short wait is soaked up by the capture buffer behind us.
+        synchronized(ackLock) {
+            while (started && inFlight >= maxUnacked) {
+                val waited = System.currentTimeMillis() - lastAckAt
+                if (waited > STALL_MS) {
+                    // A lost ack must not silence the stream for good; after a stall assume the window cleared.
+                    // A car that never acks (the 2024 VW, the Bolt) hits this every chunk: say so
+                    // once, then now and then, so the rest of the log stays readable.
+                    if (stalls++ % 500 == 0) {
+                        GearslipLog.w("$tag: no ack for ${STALL_MS}ms with $inFlight in flight - reopening the window ($stalls times)")
+                    }
+                    inFlight = 0
+                    break
+                }
+                ackLock.wait(STALL_MS - waited + 1)
             }
         }
+        if (!started) {
+            dropped++
+            return
+        }
         val timestamp = ByteArray(8)
         val micros = System.nanoTime() / 1_000
         for (i in 0 until 8) timestamp[i] = ((micros shr ((7 - i) * 8)) and 0xFF).toByte()
         try {
-            sendOnChannel(MSG_DATA, timestamp + pcm.copyOf(size))
+            sendOnChannel(MSG_DATA, timestamp + payload)
         } catch (e: java.io.IOException) {
-            GearslipLog.e("audio: the link died mid-stream", e)
+            GearslipLog.e("$tag: the link died mid-stream", e)
             started = false
             return
         }
-        inFlight++
+        synchronized(ackLock) { inFlight++ }
         chunks++
-        bytes += size
+        bytes += payload.size
         // The first chunk proves the whole path; after that, an occasional line is enough to show
         // the car is still taking audio and to catch a window that has quietly closed.
         if (chunks == 1 || chunks % CHUNK_LOG_EVERY == 0) {
             GearslipLog.i(
-                "audio: -> $chunks chunks / $bytes bytes, inFlight=$inFlight/$maxUnacked, " +
+                "$tag: -> $chunks chunks / $bytes bytes, inFlight=$inFlight/$maxUnacked, " +
                     "dropped=$dropped, focus=${if (focusGranted) "granted" else "not granted"}",
             )
         }
@@ -217,7 +287,7 @@ class AudioLink(
         configTimer = null
         stop()
         ready = false
-        CarAudio.detach(this)
+        onClose(this)
     }
 
     companion object {
@@ -230,18 +300,24 @@ class AudioLink(
         private const val MSG_STOP = 32770
         private const val MSG_CONFIG = 32771
         private const val MSG_ACK = 32772
+        private const val MSG_SETUP_ANSWER = 255
         private const val STATUS_READY = 2
         private const val FOCUS_GAIN = 1
         private const val FOCUS_RELEASE = 4
         private const val FOCUS_STATE_GAIN = 1
         private const val FOCUS_STATE_GAIN_TRANSIENT = 2
+        private const val FOCUS_STATE_GAIN_MEDIA_ONLY = 6
+        private const val FOCUS_STATE_LOSS = 3
+        private const val FOCUS_STATE_LOSS_TRANSIENT = 5
         private const val SESSION_ID = 2
         private const val STALL_MS = 2_000L
         private const val CHUNK_LOG_EVERY = 200 // about every four seconds
-        private const val CONFIG_WAIT_MS = 2_500L
+        private const val CONFIG_WAIT_MS = 1_000L
 
+        // AudioFocusStateNotification.AudioFocusState in aasdk.
         private val FOCUS_STATES = mapOf(
-            1 to "GAIN", 2 to "GAIN_TRANSIENT", 3 to "LOSS", 4 to "LOSS_TRANSIENT",
+            1 to "GAIN", 2 to "GAIN_TRANSIENT", 3 to "LOSS", 4 to "LOSS_TRANSIENT_CAN_DUCK",
+            5 to "LOSS_TRANSIENT", 6 to "GAIN_MEDIA_ONLY", 7 to "GAIN_TRANSIENT_GUIDANCE_ONLY",
         )
     }
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/audio/CarAudio.kt

@@ -100,6 +100,26 @@ object CarAudio {
         _capture.value = Capture.DENIED
     }
 
+    private val _micBlocked = MutableStateFlow(false)
+
+    /** The microphone permission is off for good: Android refuses without asking, so say why. */
+    val micBlocked: StateFlow<Boolean> = _micBlocked.asStateFlow()
+
+    fun micBlocked() {
+        _micBlocked.value = true
+        denied()
+    }
+
+    /** The driver turned the permission back on mid-drive: ask for capture again. */
+    fun micAllowed() {
+        if (!_micBlocked.value) return
+        _micBlocked.value = false
+        if (_capture.value == Capture.DENIED) {
+            _capture.value = Capture.OFF
+            if (wanted) request()
+        }
+    }
+
     internal fun captureStarted() {
         _capture.value = Capture.ON
         link?.start()

gearslip/src/main/java/app/seb3thehacker/gearslip/audio/CarMic.kt

@@ -0,0 +1,136 @@
+package app.seb3thehacker.gearslip.audio
+
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.Protobuf
+import app.seb3thehacker.gearslip.ServiceDiscovery
+import app.seb3thehacker.gearslip.Wire
+import java.util.concurrent.LinkedBlockingQueue
+import java.util.concurrent.TimeUnit
+
+/**
+ * The car's own microphone, which most head units offer over the same link as the screen:
+ *
+ *   -> CHANNEL_OPEN_REQUEST          <- CHANNEL_OPEN_RESPONSE
+ *   -> Setup { config_index }        <- Config
+ *   -> VoiceSessionNotification { START }   (control channel)
+ *   -> MicrophoneRequest { open }    <- MicrophoneResponse { status, session_id }
+ *   <- Data { 8-byte timestamp, PCM }...   -> Ack { session_id, ack }
+ *   -> MicrophoneRequest { open = false }
+ *   -> VoiceSessionNotification { END }
+ *
+ * The channel opens with the session, but the car only records between [start] and [stop], and
+ * only inside a voice session: the 2024 VW answered a bare MicrophoneRequest with status -7.
+ * Speech wants 16 kHz mono; a car that records at a multiple of that is averaged down to it, and
+ * one that doesn't isn't used, so voice falls back to the phone's microphone.
+ */
+class CarMic(
+    private val service: ServiceDiscovery.AudioService,
+    private val sendOnChannel: (messageId: Int, body: ByteArray) -> Unit,
+    private val voiceSession: (start: Boolean) -> Unit,
+) {
+    val channelId get() = service.serviceId
+
+    private val config = service.configs.first()
+    private val step = config.sampleRate / RATE
+    private val usable = service.codecType == ServiceDiscovery.CODEC_PCM && config.bits == 16 &&
+        config.sampleRate % RATE == 0 && step >= 1 && config.channels in 1..2
+
+    @Volatile private var ready = false
+    @Volatile private var listening = false
+    @Volatile private var session = 0
+    private var packets = 0
+    private val chunks = LinkedBlockingQueue<ShortArray>()
+
+    fun onMessage(messageId: Int, body: ByteArray) {
+        when (messageId) {
+            MSG_CHANNEL_OPEN_RESPONSE -> {
+                val status = Protobuf.readInt32Field(body, 1) ?: 0
+                GearslipLog.i("mic: <- ChannelOpenResponse: status=$status")
+                if (status != 0) return
+                // Setup { type = the codec }, as for audio: 0 got UNEXPECTED_MESSAGE from the VW.
+                sendOnChannel(MSG_SETUP, Protobuf.varintField(1, service.codecType.toLong()))
+                ready = usable
+                if (!usable) {
+                    GearslipLog.w(
+                        "mic: the car records ${service.codecName} ${config.sampleRate}Hz/${config.bits}bit/x${config.channels}, " +
+                            "which speech can't use - voice stays on the phone's microphone",
+                    )
+                }
+            }
+
+            MSG_CONFIG -> GearslipLog.i("mic: <- Config status=${Wire.varint(Wire.fields(body), 1)}")
+
+            MSG_MIC_RESPONSE -> {
+                val fields = Wire.fields(body)
+                session = Wire.varint(fields, 2)?.toInt() ?: 0
+                GearslipLog.i("mic: <- MicrophoneResponse status=${Wire.varint(fields, 1)} session=$session")
+            }
+
+            MSG_DATA -> {
+                sendOnChannel(MSG_ACK, Protobuf.varintField(1, session.toLong()) + Protobuf.varintField(2, 1L))
+                if (!listening || body.size <= TIMESTAMP_BYTES) return
+                if (packets++ == 0) GearslipLog.i("mic: first audio from the car (${body.size - TIMESTAMP_BYTES} bytes)")
+                chunks.offer(toSpeechRate(body))
+            }
+
+            else -> GearslipLog.i("mic: <- unhandled message id=$messageId (${body.size} bytes)")
+        }
+    }
+
+    /** Little-endian PCM after the timestamp, mixed to mono and averaged down to [RATE]. */
+    private fun toSpeechRate(body: ByteArray): ShortArray {
+        val frameBytes = 2 * config.channels
+        val frames = (body.size - TIMESTAMP_BYTES) / frameBytes
+        val out = ShortArray(frames / step)
+        for (i in out.indices) {
+            var sum = 0
+            for (s in 0 until step) {
+                val at = TIMESTAMP_BYTES + (i * step + s) * frameBytes
+                for (c in 0 until config.channels) {
+                    val o = at + 2 * c
+                    sum += (body[o].toInt() and 0xFF) or (body[o + 1].toInt() shl 8)
+                }
+            }
+            out[i] = (sum / (step * config.channels)).toShort()
+        }
+        return out
+    }
+
+    /** Asks the car to start recording. False when it can't, so the phone's microphone is used. */
+    fun start(): Boolean {
+        if (!ready) return false
+        chunks.clear()
+        packets = 0
+        listening = true
+        voiceSession(true)
+        sendOnChannel(MSG_MIC_REQUEST, Protobuf.varintField(1, 1L) + Protobuf.varintField(4, 1L))
+        GearslipLog.i("mic: -> MicrophoneRequest(open)")
+        return true
+    }
+
+    /** The next piece of audio, or null if the car sent nothing for [timeoutMs]. */
+    fun read(timeoutMs: Long): ShortArray? = chunks.poll(timeoutMs, TimeUnit.MILLISECONDS)
+
+    fun stop() {
+        if (!listening) return
+        listening = false
+        sendOnChannel(MSG_MIC_REQUEST, Protobuf.varintField(1, 0L))
+        voiceSession(false)
+        GearslipLog.i("mic: -> MicrophoneRequest(close) after $packets packets, voice session ended")
+    }
+
+    companion object {
+        /** The connected car's microphone, or null with no car or one that has none. */
+        @Volatile var current: CarMic? = null
+
+        const val RATE = 16_000
+        private const val TIMESTAMP_BYTES = 8
+        private const val MSG_CHANNEL_OPEN_RESPONSE = 8
+        private const val MSG_DATA = 0
+        private const val MSG_SETUP = 32768
+        private const val MSG_CONFIG = 32771
+        private const val MSG_ACK = 32772
+        private const val MSG_MIC_REQUEST = 32773
+        private const val MSG_MIC_RESPONSE = 32774
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/call/CarCalls.kt

@@ -0,0 +1,135 @@
+package app.seb3thehacker.gearslip.call
+
+import android.Manifest
+import android.content.Context
+import android.content.pm.PackageManager
+import android.net.Uri
+import android.os.Handler
+import android.os.Looper
+import android.provider.ContactsContract
+import android.telecom.TelecomManager
+import android.telephony.TelephonyCallback
+import android.telephony.TelephonyManager
+import app.seb3thehacker.gearslip.GearslipLog
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/** A caller as the car shows it: whatever the contacts app knows, or just the number. */
+data class Caller(val number: String, val name: String?) {
+    val label: String get() = name ?: number.ifBlank { "Unknown number" }
+}
+
+sealed interface CallUiState {
+    data object None : CallUiState
+    data class Ringing(val caller: Caller, val canDecline: Boolean) : CallUiState
+    data class Active(val caller: Caller?) : CallUiState
+}
+
+/**
+ * Tracks the phone's call state for the car screen, and answers or declines through the two
+ * doors a sideloaded app can use: [android.telecom.TelecomManager.acceptRingingCall] to answer,
+ * and [GearslipCallScreening]'s response to decline one that is still ringing.
+ *
+ * Ending a call already answered needs MODIFY_PHONE_STATE, a privileged permission Gearslip
+ * cannot hold, so a call taken here is finished the way it would be without Gearslip at all -
+ * from the phone itself, a paired headset, or the car's own Bluetooth if it has any. Call audio
+ * stays on the phone's normal voice path too; nothing here sends it over the USB link, which
+ * only ever carries media playback.
+ */
+object CarCalls {
+
+    private val _state = MutableStateFlow<CallUiState>(CallUiState.None)
+    val state: StateFlow<CallUiState> = _state.asStateFlow()
+
+    private var telephony: TelephonyManager? = null
+    private var watcher: TelephonyCallback? = null
+    private var pendingRespond: ((allow: Boolean) -> Unit)? = null
+    private var ringingCaller: Caller? = null
+
+    fun start(context: Context) {
+        if (watcher != null) return
+        if (context.checkSelfPermission(Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) return
+        val manager = context.getSystemService(TelephonyManager::class.java) ?: return
+        val callback = object : TelephonyCallback(), TelephonyCallback.CallStateListener {
+            override fun onCallStateChanged(state: Int) = onPhoneState(state)
+        }
+        runCatching { manager.registerTelephonyCallback(context.mainExecutor, callback) }
+            .onSuccess { telephony = manager; watcher = callback }
+            .onFailure { GearslipLog.w("calls: could not watch call state: ${it.message}") }
+    }
+
+    fun stop() {
+        val callback = watcher ?: return
+        runCatching { telephony?.unregisterTelephonyCallback(callback) }
+        telephony = null
+        watcher = null
+        pendingRespond = null
+        ringingCaller = null
+        _state.value = CallUiState.None
+    }
+
+    private fun onPhoneState(state: Int) {
+        when (state) {
+            TelephonyManager.CALL_STATE_IDLE -> {
+                pendingRespond = null
+                ringingCaller = null
+                _state.value = CallUiState.None
+            }
+            TelephonyManager.CALL_STATE_OFFHOOK -> {
+                pendingRespond = null
+                _state.value = CallUiState.Active(ringingCaller)
+            }
+            TelephonyManager.CALL_STATE_RINGING -> {
+                // The number itself only ever arrives through the screening service; if this
+                // fires first, the ringing card appears once incomingCall() catches up.
+                ringingCaller?.let { _state.value = CallUiState.Ringing(it, pendingRespond != null) }
+            }
+        }
+    }
+
+    /** Called by [GearslipCallScreening] the moment a call comes in - the only place with a number. */
+    fun incomingCall(context: Context, number: String?, respond: (allow: Boolean) -> Unit) {
+        val caller = Caller(number.orEmpty(), number?.let { lookUpName(context, it) })
+        ringingCaller = caller
+        pendingRespond = respond
+        _state.value = CallUiState.Ringing(caller, canDecline = true)
+    }
+
+    /** The screening window closed by itself - the call rings normally now, and can't be declined from here. */
+    fun screeningExpired() {
+        pendingRespond = null
+        val caller = ringingCaller ?: return
+        if (_state.value is CallUiState.Ringing) _state.value = CallUiState.Ringing(caller, canDecline = false)
+    }
+
+    fun decline() {
+        val respond = pendingRespond ?: return
+        pendingRespond = null
+        runCatching { respond(false) }.onFailure { GearslipLog.w("calls: decline failed: ${it.message}") }
+    }
+
+    fun answer(context: Context) {
+        if (context.checkSelfPermission(Manifest.permission.ANSWER_PHONE_CALLS) != PackageManager.PERMISSION_GRANTED) {
+            GearslipLog.w("calls: answer needs ANSWER_PHONE_CALLS, which was never granted")
+            return
+        }
+        val telecom = context.getSystemService(TelecomManager::class.java) ?: return
+        runCatching { telecom.acceptRingingCall() }
+            .onFailure { GearslipLog.w("calls: answer failed: ${it.message}") }
+    }
+
+    private fun lookUpName(context: Context, number: String): String? {
+        if (context.checkSelfPermission(Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) return null
+        return runCatching {
+            val uri = Uri.withAppendedPath(ContactsContract.PhoneLookup.CONTENT_FILTER_URI, Uri.encode(number))
+            context.contentResolver.query(uri, arrayOf(ContactsContract.PhoneLookup.DISPLAY_NAME), null, null, null)
+                ?.use { c -> if (c.moveToFirst()) c.getString(0) else null }
+        }.getOrNull()
+    }
+}
+
+/** Posts to the main thread after a delay - used to give up on a screening response Gearslip never sent. */
+internal fun mainThreadDelay(ms: Long, action: () -> Unit) {
+    Handler(Looper.getMainLooper()).postDelayed(action, ms)
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/call/GearslipCallScreening.kt

@@ -0,0 +1,53 @@
+package app.seb3thehacker.gearslip.call
+
+import android.telecom.Call
+import android.telecom.CallScreeningService
+import app.seb3thehacker.gearslip.GearslipLog
+
+/**
+ * Sees every incoming call before it rings, so the car screen can show who is calling and
+ * decline it in the same window a spam-blocker would use. Inert until the driver sets Gearslip
+ * as the phone's caller ID and spam app - the same on-device consent Truecaller-style apps ask
+ * for, not a privileged permission.
+ *
+ * The system gives an app a few seconds to answer before it lets the call ring on its own, so a
+ * response is sent either when the driver taps a button or when that window is about to close,
+ * whichever comes first. Answering a call that has already passed this point still works, since
+ * [CarCalls.answer] goes through the ordinary ringing-call API rather than through screening.
+ */
+class GearslipCallScreening : CallScreeningService() {
+
+    override fun onScreenCall(callDetails: Call.Details) {
+        val number = callDetails.handle?.schemeSpecificPart
+        var responded = false
+
+        val respond: (Boolean) -> Unit = { allow ->
+            if (!responded) {
+                responded = true
+                runCatching {
+                    respondToCall(
+                        callDetails,
+                        CallResponse.Builder()
+                            .setDisallowCall(!allow)
+                            .setRejectCall(!allow)
+                            .setSkipNotification(false)
+                            .build(),
+                    )
+                }.onFailure { GearslipLog.w("calls: screening response failed: ${it.message}") }
+            }
+        }
+
+        CarCalls.incomingCall(applicationContext, number, respond)
+
+        // Answer for the system if nobody has by the time its own patience runs out, so a call
+        // Gearslip is slow to show never gets silently blocked.
+        mainThreadDelay(SCREENING_WINDOW_MS) {
+            respond(true)
+            CarCalls.screeningExpired()
+        }
+    }
+
+    private companion object {
+        const val SCREENING_WINDOW_MS = 3_500L
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/AssistantCommands.kt

@@ -0,0 +1,385 @@
+package app.seb3thehacker.gearslip.car
+
+import android.content.Context
+import app.seb3thehacker.gearslip.media.CarMedia
+import app.seb3thehacker.gearslip.speech.VoiceFocus
+import java.text.DateFormat
+import java.util.Date
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.withContext
+import kotlinx.coroutines.withTimeoutOrNull
+
+/**
+ * Turns what [CarAssistant] heard into an action plus something to say back.
+ *
+ * Deliberately small and keyword-matched rather than run through any NLU or bundled model: a
+ * fixed set of things a driver actually wants hands-free (media, calling, opening an app,
+ * getting back Home), covering the same ground the rest of the car UI already does rather than
+ * trying to be a general assistant.
+ */
+object AssistantCommands {
+
+    suspend fun handle(context: Context, navigator: CarNavigator, frame: CarEnvironment.Frame, heardRaw: String): String {
+        val heard = natural(heardRaw)
+        VoiceHelp.hide()
+        if (heard in HELP_WORDS || heard.startsWith("what can i say") || heard.startsWith("what can you do")) {
+            VoiceHelp.show()
+            return "Here's what you can say."
+        }
+        if (heard.matches(Regex("(fuck|f\\*+) (you|off)( too)?"))) return "Fuck you too."
+
+        navigateCommand(context, navigator, frame, heard)?.let { return it }
+        playSearchCommand(context, navigator, heard)?.let { return it }
+        mediaCommand(heard)?.let { return it }
+        navCommand(navigator, heard)?.let { return it }
+        infoCommand(heard)?.let { return it }
+        callCommand(context, heard)?.let { return it }
+        openAppCommand(context, navigator, frame, heard)?.let { return it }
+
+        return "I don't know how to do that yet."
+    }
+
+    /**
+     * What was said, minus the padding people wrap a command in: "hey", "can you", "I want to",
+     * "please", "thanks". Each command below then only has to know its own words.
+     */
+    private fun natural(raw: String): String {
+        var t = raw.lowercase().replace(Regex("[.,!?]"), " ").replace(Regex("\\s+"), " ").trim()
+        var changed = true
+        while (changed) {
+            changed = false
+            for (lead in LEAD_FILLERS) if (t.startsWith("$lead ")) { t = t.removePrefix("$lead ").trim(); changed = true }
+            for (tail in TAIL_FILLERS) if (t.endsWith(" $tail")) { t = t.removeSuffix(" $tail").trim(); changed = true }
+        }
+        return t
+    }
+
+    /** The part after the first of [triggers] that [text] starts with, or null. */
+    private fun after(text: String, triggers: List<String>): String? =
+        triggers.firstOrNull { text.startsWith(it) }?.let { text.removePrefix(it).trim() }
+
+    private suspend fun allEntries(context: Context): List<Entry> {
+        val vehicleData = CarSettings.experimentalFeaturesEnabled.value && CarSettings.carSensorsEnabled.value
+        val builtIn = BuiltInApps.entries.filter { it.builtIn !== BuiltInApps.VehicleData || vehicleData }
+        return builtIn + (LauncherCache.entries ?: withContext(Dispatchers.IO) { LauncherCache.load(context) })
+    }
+
+    /**
+     * Best label match: exact, then a label starting with [name], then one containing it. Spaces
+     * and punctuation don't count, since the recognizer may hear "MapQuest" as "map quest".
+     */
+    private fun <T> bestMatch(items: List<T>, name: String, label: (T) -> String): T? {
+        val n = squash(name.removePrefix("the ").removePrefix("my ").removeSuffix(" app"))
+        if (n.isEmpty()) return null
+        items.firstOrNull { squash(label(it)) == n }?.let { return it }
+        // Loose matches need a real word: "pizza in a" mustn't pick "Organic Maps" for its "a".
+        if (n.length < 3) return null
+        return items.firstOrNull { squash(label(it)).startsWith(n) }
+            ?: items.firstOrNull { squash(label(it)).contains(n) }
+    }
+
+    private fun squash(s: String) = s.lowercase().filter { it.isLetterOrDigit() }
+
+    /**
+     * "navigate to X [with|using|on|via Y]" - Y picks the nav app by (partial) label; without it,
+     * whichever nav app was used last, or the only one installed, or the first one found. Starts
+     * it straight into navigating there via [CarAppConnection]'s `ACTION_NAVIGATE` deep link -
+     * the same one Android Auto's own Assistant integration uses - rather than opening the app
+     * and leaving the driver to type the address in on the car keyboard.
+     */
+    private suspend fun navigateCommand(
+        context: Context,
+        navigator: CarNavigator,
+        frame: CarEnvironment.Frame,
+        heard: String,
+    ): String? {
+        // "use Organic Maps to get to X", "open OsmAnd and navigate to X": the app comes first.
+        var text = heard
+        var leadingApp: String? = null
+        Regex("^(?:use|using|with|open|in|on) (.+?) (?:to |and )(.+)$").find(text)?.let { m ->
+            if (after(m.groupValues[2], NAVIGATE_TRIGGERS) != null) {
+                leadingApp = m.groupValues[1]
+                text = m.groupValues[2]
+            }
+        }
+        var destination = after(text, NAVIGATE_TRIGGERS) ?: return null
+        if (destination.isBlank()) return "Where to?"
+
+        val entries = allEntries(context)
+        // "go to Spotify" means the app, and "go to settings" the screen; "go to Target" is a place.
+        val asApp = destination.removePrefix("the ").removeSuffix(" app")
+        if (text.startsWith("go to ") &&
+            (asApp in SCREEN_WORDS || asApp in APP_NICKNAMES || entries.any { it.label.lowercase() == asApp })
+        ) {
+            return null
+        }
+        val navApps = entries.filter { it.template?.isNavigation == true }
+        if (navApps.isEmpty()) return "You don't have any navigation apps installed."
+
+        // "X with Organic Maps", "X on OsmAnd": split only when the end names a nav app, so a
+        // place like "Starbucks on Main Street" stays whole.
+        var chosenApp = leadingApp?.let { name -> bestMatch(navApps, name) { it.label } ?: return "I couldn't find a navigation app called $name." }
+        if (chosenApp == null) {
+            for (sep in listOf(" with ", " using ", " on ", " via ", " in ", " through ")) {
+                val at = destination.lastIndexOf(sep)
+                if (at <= 0) continue
+                val app = bestMatch(navApps, destination.substring(at + sep.length)) { it.label } ?: continue
+                chosenApp = app
+                destination = destination.substring(0, at).trim()
+                break
+            }
+        }
+        // "the nearest gas station" -> "gas station": the map app already searches around the car
+        // and AutoRoute picks the nearest result, and Organic Maps took "nearest" as part of the name.
+        val (place, nearby) = plainPlace(destination)
+        destination = place
+        if (destination.isBlank()) return "Where to?"
+
+        val chosen = chosenApp ?: when {
+            navApps.size == 1 -> navApps.first()
+            else -> navApps.firstOrNull { it.componentId == CarSettings.lastNav.value } ?: navApps.first()
+        }
+        val template = chosen.template ?: return "That's not a navigation app."
+
+        CarServices.connectNav(template, frame, destination)
+        navigator.home()
+        return if (nearby) "Finding the nearest $destination with ${chosen.label}." else "Navigating to $destination with ${chosen.label}."
+    }
+
+    /** [destination] without "a", "the nearest", "near me" and the like, and whether any of that said "close by". */
+    private fun plainPlace(destination: String): Pair<String, Boolean> {
+        var t = destination
+        var nearby = false
+        var changed = true
+        while (changed) {
+            changed = false
+            for (lead in PLACE_LEADS) if (t.startsWith(lead)) {
+                t = t.removePrefix(lead).trim(); changed = true
+                if (lead.trim() !in ARTICLES) nearby = true
+            }
+            for (tail in PLACE_TAILS) if (t.endsWith(tail)) { t = t.removeSuffix(tail).trim(); changed = true; nearby = true }
+        }
+        return t to nearby
+    }
+
+    /**
+     * "play X" with something after it: a song, artist, album or playlist, asked of the music app
+     * that's open through its own search ([CarMedia.search]). A bare "play", or "play music",
+     * falls through to resume.
+     */
+    private suspend fun playSearchCommand(context: Context, navigator: CarNavigator, heard: String): String? {
+        var query = after(heard, PLAY_TRIGGERS) ?: return null
+        query = query.removePrefix("some ").trim()
+        if (query.isEmpty() || query in RESUME_WORDS) return null
+        val media = CarServices.media
+
+        // "play Daft Punk on Metrolist": switch to that app first, if it's one we know.
+        for (sep in listOf(" on ", " in ", " from ", " with ", " using ")) {
+            val at = query.lastIndexOf(sep)
+            if (at <= 0) continue
+            val apps = withContext(Dispatchers.IO) { app.seb3thehacker.gearslip.media.MediaCatalog.installed(context) }
+            val wanted = bestMatch(apps, query.substring(at + sep.length)) { it.label } ?: continue
+            query = query.substring(0, at).trim()
+            if (query.isEmpty() || query in RESUME_WORDS) {
+                CarServices.openMedia(wanted, autoplay = true)
+                navigator.media()
+                return "Opening ${wanted.label}."
+            }
+            if (CarServices.mediaApp.value?.component != wanted.component) {
+                CarServices.openMedia(wanted)
+                navigator.media()
+                // Give it a moment to connect before asking it to search.
+                withTimeoutOrNull(APP_CONNECT_MS) {
+                    while (media.appLabel == null || (!media.canSearchLibrary && !media.now.value.canSearch)) delay(200)
+                }
+            }
+            break
+        }
+
+        // No music app open, or its connection is gone (the app was closed): use the one played
+        // last, the way "play X" works on Android Auto.
+        val phase = media.phase.value
+        if (media.appLabel == null || phase == CarMedia.Phase.IDLE || phase == CarMedia.Phase.REJECTED) {
+            if (!CarServices.reopenLastMedia()) return "Open a music app first, then ask again."
+            navigator.media()
+        }
+        withTimeoutOrNull(APP_CONNECT_MS) {
+            while (media.phase.value != CarMedia.Phase.READY || media.appLabel == null ||
+                (!media.canSearchLibrary && !media.now.value.canSearch)
+            ) delay(200)
+        }
+        val app = media.appLabel ?: return "Your music app didn't open in time. Try again."
+        if (!media.canSearchLibrary && !media.now.value.canSearch) {
+            return "$app ignores voice searches. Pick something on its screen instead."
+        }
+        media.playBestMatch(query)
+        return "Looking for $query on $app."
+    }
+
+    private fun mediaCommand(heard: String): String? {
+        val media = CarServices.media
+        return when {
+            "pause" in heard || heard.startsWith("stop") || heard == "quiet" || heard == "shut up" -> {
+                media.pause()
+                VoiceFocus.afterRelease { media.pause() }
+                "Paused."
+            }
+            "resume" in heard || "unpause" in heard || heard in RESUME_PHRASES ||
+                (heard.startsWith("play") && "playing" !in heard) -> {
+                if (!media.now.value.playing) media.togglePlay()
+                "Playing."
+            }
+            "next" in heard || "skip" in heard || heard.startsWith("change the song") -> {
+                media.next()
+                "Skipping."
+            }
+            "previous" in heard || "last song" in heard || "back song" in heard || "go back a song" in heard ||
+                "play that again" in heard || "replay" in heard -> {
+                media.previous()
+                "Playing the previous track."
+            }
+            ("what" in heard && "playing" in heard) || "what song" in heard || "who sings" in heard ||
+                "who's singing" in heard || "who is singing" in heard || "what's this song" in heard ||
+                "name of this song" in heard -> {
+                val now = media.now.value
+                if (now.isActive) listOf(now.title, now.artist).filter { it.isNotBlank() }.joinToString(" by ")
+                else "Nothing's playing."
+            }
+            else -> null
+        }
+    }
+
+    private fun navCommand(navigator: CarNavigator, heard: String): String? = when {
+        heard == "go back" || heard == "back" -> {
+            navigator.back()
+            "Going back."
+        }
+        heard in EXIT_WORDS -> {
+            BuiltInApps.Exit.open(navigator)
+            "Back to the car's screen."
+        }
+        "go home" in heard || heard == "home" || heard == "home screen" || "go to the home screen" in heard -> {
+            navigator.home()
+            "Heading home."
+        }
+        "open apps" in heard || heard == "apps" || "app list" in heard || "all apps" in heard || "my apps" in heard || heard == "go to apps" -> {
+            navigator.apps()
+            "Here are your apps."
+        }
+        "settings" in heard -> {
+            navigator.settings()
+            "Opening settings."
+        }
+        "vehicle data" in heard || "car data" in heard -> {
+            if (CarSettings.experimentalFeaturesEnabled.value && CarSettings.carSensorsEnabled.value) {
+                navigator.vehicleData()
+                "Opening vehicle data."
+            } else {
+                "Vehicle data is off. Turn it on under experimental features in settings."
+            }
+        }
+        else -> null
+    }
+
+    private fun infoCommand(heard: String): String? = when {
+        "what time" in heard || "what's the time" in heard || heard == "time" || "the time" in heard ->
+            "It's ${DateFormat.getTimeInstance(DateFormat.SHORT).format(Date())}."
+        "weather" in heard || "going to rain" in heard || "gonna rain" in heard || "how hot" in heard ||
+            "how cold" in heard || "temperature outside" in heard -> {
+            val data = (Weather.state.value as? WeatherState.Ready)?.data
+            if (data != null) "${data.temp}${data.tempUnit} and ${Weather.describe(data.code)} in ${data.place}."
+            else "I don't have the weather yet."
+        }
+        else -> null
+    }
+
+    private suspend fun callCommand(context: Context, heard: String): String? {
+        val name = (
+            after(heard, CALL_TRIGGERS)
+                ?: Regex("^give (.+) a (?:call|ring)$").find(heard)?.groupValues?.get(1)
+                ?: return null
+            ).replace(Regex(" (?:on|at) (?:their |his |her )?(?:mobile|cell|phone|home|work)$"), "").trim()
+        if (name.isBlank()) return "Who should I call?"
+        if (!hasCallPermissions(context)) return "Gearslip needs the phone and contacts permissions first, from the phone screen."
+
+        val match = withContext(Dispatchers.IO) {
+            loadContacts(context).firstOrNull { it.name.lowercase().contains(name) }
+        } ?: return "I couldn't find $name in your contacts."
+
+        placeCall(context, match.number)
+        return "Calling ${match.name}."
+    }
+
+    private suspend fun openAppCommand(
+        context: Context,
+        navigator: CarNavigator,
+        frame: CarEnvironment.Frame,
+        heard: String,
+    ): String? {
+        val name = (after(heard, OPEN_TRIGGERS) ?: return null)
+            .removePrefix("the ").removePrefix("my ").removeSuffix(" app").trim()
+        if (name.isBlank()) return null
+        val wanted = APP_NICKNAMES[name] ?: name
+
+        // Gearslip's own apps come first in the list, so "phone" opens its dialer, not the phone's.
+        val match = bestMatch(allEntries(context), wanted) { it.label }
+            ?: return "I couldn't find an app called $name."
+
+        launchEntry(match, navigator, frame)
+        return "Opening ${match.label}."
+    }
+
+    private val EXIT_WORDS = setOf("exit", "exit gearslip", "close gearslip", "quit", "quit gearslip", "open exit")
+
+    /** Other names people use for Gearslip's own apps. */
+    private val APP_NICKNAMES = mapOf(
+        "web" to "browser", "internet" to "browser", "the web" to "browser", "web browser" to "browser",
+        "dialer" to "phone", "the dialer" to "phone", "keypad" to "phone",
+        "screen share" to "screen sharing", "screen mirroring" to "screen sharing", "mirroring" to "screen sharing",
+    )
+
+    private val NAVIGATE_TRIGGERS = listOf(
+        "navigate to ", "navigate me to ", "directions to ", "get directions to ", "give me directions to ",
+        "take me to ", "drive to ", "drive me to ", "get me to ", "go to ", "head to ", "route to ",
+        "how do i get to ", "show me the way to ", "find a route to ", "navigation to ", "get to ",
+        // Last, so "navigate to" wins: the recognizer sometimes drops the "to".
+        "navigate me ", "navigate ", "find me the nearest ", "find the nearest ", "find the closest ",
+    )
+
+    private val ARTICLES = setOf("a", "an", "the", "some")
+    // Longest first, so "the nearest " goes before "the ".
+    private val PLACE_LEADS = listOf(
+        "the nearest ", "the closest ", "a nearby ", "the nearby ", "nearest ", "closest ", "nearby ",
+        "a ", "an ", "some ",
+    )
+    private val PLACE_TAILS = listOf(" near me", " nearby", " near here", " around here", " close by", " closest to me")
+
+    private val PLAY_TRIGGERS = listOf("play me ", "play ", "put on ", "listen to ", "i want to hear ", "shuffle ")
+
+    private val CALL_TRIGGERS = listOf("call ", "phone ", "dial ", "ring ", "make a call to ", "place a call to ", "start a call with ")
+
+    private val OPEN_TRIGGERS = listOf("open ", "launch ", "start ", "go to ", "switch to ", "show me ", "bring up ", "pull up ")
+
+    /** Screens "go to X" means rather than a place. */
+    private val SCREEN_WORDS = setOf("settings", "home", "the home screen", "home screen", "apps", "my apps", "all apps")
+
+    /** Padding stripped from the front of a command, longest first where they overlap. */
+    private val LEAD_FILLERS = listOf(
+        "hey gearslip", "ok gearslip", "okay gearslip", "gearslip", "hey", "ok", "okay", "um", "uh", "so",
+        "please", "can you please", "can you", "could you", "would you", "will you", "can i", "could i",
+        "i want you to", "i want to", "i'd like to", "i would like to", "i wanna", "i need to", "i need you to",
+        "let's", "lets", "go ahead and", "just", "now", "quickly",
+    )
+
+    /** Longest first, so "right now" goes whole rather than leaving "right". */
+    private val TAIL_FILLERS = listOf("thank you very much", "thank you", "right now", "for me", "please", "thanks", "now")
+
+    private const val APP_CONNECT_MS = 5_000L
+
+    private val HELP_WORDS = setOf("help", "commands", "voice commands", "list commands", "show commands")
+
+    private val RESUME_WORDS = setOf("music", "the music", "some music", "something", "it", "again", "that", "my music")
+
+    private val RESUME_PHRASES = setOf("keep playing", "continue", "keep going", "start the music", "music on", "turn the music back on")
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/AssistantOverlay.kt

@@ -0,0 +1,140 @@
+package app.seb3thehacker.gearslip.car
+
+import app.seb3thehacker.gearslip.car.theme.*
+import android.content.Intent
+import android.net.Uri
+import android.provider.Settings
+import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.animation.core.RepeatMode
+import androidx.compose.animation.core.animateFloat
+import androidx.compose.animation.core.infiniteRepeatable
+import androidx.compose.animation.core.rememberInfiniteTransition
+import androidx.compose.animation.core.tween
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.ui.draw.drawBehind
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.scale
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.res.vectorResource
+import app.seb3thehacker.gearslip.R
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+
+/**
+ * What the assistant hears and says, laid over the bottom of whatever screen is up: a dark shade
+ * so white words read over a bright map, and a glow along the bottom edge in the phone's own
+ * colours that breathes while listening. The shade passes touches through; only the buttons take them.
+ */
+@Composable
+fun AssistantOverlay(modifier: Modifier = Modifier) {
+    val state by CarAssistant.state.collectAsState()
+    if (state.phase == CarAssistant.Phase.IDLE) return
+    val context = LocalContext.current
+    val listening = state.phase == CarAssistant.Phase.LISTENING && state.ready
+    val glow = MaterialTheme.colorScheme.primary
+    val glow2 = MaterialTheme.colorScheme.tertiary
+    val breathe by rememberInfiniteTransition(label = "glow").animateFloat(
+        0.55f, 1f, infiniteRepeatable(tween(900, easing = FastOutSlowInEasing), RepeatMode.Reverse), label = "glow",
+    )
+    val strength = when (state.phase) {
+        CarAssistant.Phase.LISTENING -> if (state.ready) breathe else 0.3f
+        CarAssistant.Phase.ERROR -> 0.3f
+        else -> 0.6f
+    }
+
+    Box(
+        modifier
+            .fillMaxWidth()
+            .drawBehind {
+                drawRect(Brush.verticalGradient(0f to Color.Transparent, 0.45f to Color.Black.copy(alpha = 0.6f), 1f to Color.Black.copy(alpha = 0.85f)))
+                // A wide, flat oval of light rising from the bottom edge.
+                scale(1f, 0.22f, Offset(size.width / 2, size.height)) {
+                    drawCircle(
+                        Brush.radialGradient(
+                            0f to glow.copy(alpha = 0.9f * strength), 0.5f to glow2.copy(alpha = 0.35f * strength), 1f to Color.Transparent,
+                            center = Offset(size.width / 2, size.height), radius = size.width * 0.55f,
+                        ),
+                        radius = size.width * 0.55f, center = Offset(size.width / 2, size.height),
+                    )
+                }
+            }
+            .padding(start = 16.dp, end = 16.dp, top = 56.dp, bottom = 20.dp),
+    ) {
+        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+            PulsingMic(listening)
+            Column(Modifier.weight(1f), horizontalAlignment = Alignment.CenterHorizontally) {
+                val (small, big) = when (state.phase) {
+                    CarAssistant.Phase.LISTENING -> "" to state.heard.ifBlank { if (state.ready) "Listening…" else "One moment…" }
+                    CarAssistant.Phase.THINKING -> "" to state.heard.ifBlank { "…" }
+                    else -> state.heard to state.reply
+                }
+                if (small.isNotBlank()) {
+                    Text(small, color = Color.White.copy(alpha = 0.7f), style = MaterialTheme.typography.bodyLarge, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                }
+                Text(
+                    big,
+                    color = if (big == "Listening…" || big == "One moment…" || big == "…") Color.White.copy(alpha = 0.7f) else Color.White,
+                    style = MaterialTheme.typography.headlineSmall,
+                    fontWeight = FontWeight.SemiBold,
+                    textAlign = TextAlign.Center,
+                    maxLines = 2,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
+            if (state.missingPermission) {
+                GsButton(tone = GsTone.Tonal, onClick = {
+                    context.startActivity(
+                        Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", context.packageName, null)),
+                    )
+                }) { Text("Grant") }
+            }
+            GsIconButton(Icons.Filled.Close, "Dismiss", CarAssistant::cancel)
+        }
+    }
+}
+
+/** A filled circle with a mic glyph, pulsing gently while actually listening. */
+@Composable
+private fun PulsingMic(listening: Boolean, modifier: Modifier = Modifier) {
+    Surface(
+        shape = CircleShape,
+        color = MaterialTheme.colorScheme.primary,
+        contentColor = MaterialTheme.colorScheme.onPrimary,
+        modifier = modifier.size(36.dp),
+    ) {
+        Row(horizontalArrangement = Arrangement.Center) {
+            MicGlyph(Modifier.padding(8.dp).size(20.dp))
+        }
+    }
+    // `listening` only changes what's drawn elsewhere in the row (the "Listening…" label);
+    // the glyph itself doesn't need to animate for this to read clearly on a glance.
+}
+
+/** The assistant's mic, from `R.drawable.mic_24`, tinted with the current content colour. */
+@Composable
+fun MicGlyph(modifier: Modifier = Modifier) {
+    Icon(ImageVector.vectorResource(R.drawable.mic_24), contentDescription = "Assistant", modifier = modifier)
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/BluetoothAudioCheck.kt

@@ -0,0 +1,146 @@
+package app.seb3thehacker.gearslip.car
+
+import android.Manifest
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothA2dp
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothManager
+import android.bluetooth.BluetoothProfile
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.content.pm.PackageManager
+import android.os.Handler
+import android.os.Looper
+import app.seb3thehacker.gearslip.GearslipLog
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * With Bluetooth audio chosen, music only reaches the car if the phone is connected to it over
+ * Bluetooth. Twenty seconds after the car shows Gearslip, long enough for a car to connect on its
+ * own, this checks. If the phone isn't connected, the car and the phone's Home screen both say so,
+ * until it connects or the drive ends.
+ *
+ * When the car named its Bluetooth address, only that device counts. Otherwise any audio
+ * connection does, since there's no telling which device is the car.
+ */
+object BluetoothAudioCheck {
+
+    private val _missing = MutableStateFlow(false)
+    /** True while Bluetooth audio is chosen and the phone isn't connected to the car for it. */
+    val missing: StateFlow<Boolean> = _missing
+
+    private val _carDismissed = MutableStateFlow(false)
+    /** The driver tapped OK on the car's card; it stays away for the rest of this drive. */
+    val carDismissed: StateFlow<Boolean> = _carDismissed
+
+    private val log = GearslipLog.tagged("bluetooth")
+    private val main = Handler(Looper.getMainLooper())
+    private var appContext: Context? = null
+    private var armed = false
+    private var receiver: BroadcastReceiver? = null
+
+    fun init(context: Context) {
+        appContext = context.applicationContext
+    }
+
+    /** The car shows Gearslip. Called again whenever the video restarts, so it arms once per drive. */
+    fun onProjecting() = main.post {
+        if (armed) return@post
+        armed = true
+        main.postDelayed(::start, WAIT_MS)
+    }
+
+    fun onCarDisconnected() = main.post {
+        armed = false
+        main.removeCallbacksAndMessages(null)
+        stopWatching()
+        _missing.value = false
+        _carDismissed.value = false
+    }
+
+    fun dismissOnCar() {
+        _carDismissed.value = true
+    }
+
+    /** "Don't show again" on the car: turns the warning off in Settings, for every car. */
+    fun neverAgain() {
+        CarSettings.setBluetoothWarning(false)
+        log.i("Bluetooth audio warning turned off")
+        _carDismissed.value = true
+        _missing.value = false
+    }
+
+    private fun start() {
+        if (!armed) return
+        check()
+        // Connecting later clears the warning, and losing the connection brings it back.
+        val context = appContext ?: return
+        val r = object : BroadcastReceiver() {
+            override fun onReceive(context: Context, intent: Intent) {
+                main.postDelayed(::check, SETTLE_MS)
+            }
+        }
+        context.registerReceiver(
+            r,
+            IntentFilter(BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED).apply {
+                addAction(BluetoothAdapter.ACTION_STATE_CHANGED)
+            },
+            Context.RECEIVER_EXPORTED,
+        )
+        receiver = r
+    }
+
+    @SuppressLint("MissingPermission")
+    private fun check() {
+        if (!armed) return
+        val context = appContext ?: return
+        if (CarSettings.pipeAudio.value) {
+            set(false, "USB audio is on")
+            return
+        }
+        if (!CarSettings.bluetoothWarning.value) {
+            set(false, "the warning is turned off")
+            return
+        }
+        if (context.checkSelfPermission(Manifest.permission.BLUETOOTH_CONNECT) != PackageManager.PERMISSION_GRANTED) {
+            log.i("can't check the audio connection: the Bluetooth permission isn't granted")
+            return
+        }
+        val adapter = context.getSystemService(BluetoothManager::class.java)?.adapter ?: return
+        if (!adapter.isEnabled) {
+            set(true, "Bluetooth is off")
+            return
+        }
+        val car = CarBluetooth.carAddress?.uppercase()
+        adapter.getProfileProxy(context, object : BluetoothProfile.ServiceListener {
+            override fun onServiceConnected(profile: Int, proxy: BluetoothProfile) {
+                val connected = runCatching { proxy.connectedDevices }.getOrDefault(emptyList())
+                adapter.closeProfileProxy(profile, proxy)
+                val ok = if (car != null) connected.any { it.address.uppercase() == car } else connected.isNotEmpty()
+                main.post {
+                    set(!ok, if (ok) "connected to the car" else "not connected to the car")
+                }
+            }
+
+            override fun onServiceDisconnected(profile: Int) {}
+        }, BluetoothProfile.A2DP)
+    }
+
+    private fun set(missing: Boolean, why: String) {
+        if (!armed || _missing.value == missing) return
+        _missing.value = missing
+        log.i("Bluetooth audio: $why")
+    }
+
+    private fun stopWatching() {
+        val r = receiver ?: return
+        receiver = null
+        runCatching { appContext?.unregisterReceiver(r) }
+    }
+
+    private const val WAIT_MS = 20_000L
+    private const val SETTLE_MS = 1_000L
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/BluetoothPairOverlay.kt

@@ -0,0 +1,118 @@
+package app.seb3thehacker.gearslip.car
+
+import app.seb3thehacker.gearslip.car.theme.*
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+
+/**
+ * Asks once per car whether to pair it over Bluetooth, then waits while the phone shows its
+ * pairing dialog. See [CarBluetooth]. With no pairing to do, says when Bluetooth audio isn't
+ * connected (see [BluetoothAudioCheck]), or else when the phone's location is off (see
+ * [LocationCheck]). Unlike the call prompt, a tap outside the card does nothing:
+ * the driver picks Pair or Not now.
+ */
+@Composable
+internal fun BluetoothPairOverlay() {
+    val prompt by CarBluetooth.prompt.collectAsState()
+    val bluetoothAudio = !CarSettings.pipeAudio.collectAsState().value
+    when (prompt) {
+        CarBluetooth.Prompt.NONE -> {
+            val missing by BluetoothAudioCheck.missing.collectAsState()
+            val dismissed by BluetoothAudioCheck.carDismissed.collectAsState()
+            val warn by CarSettings.bluetoothWarning.collectAsState()
+            val locationOff by LocationCheck.off.collectAsState()
+            val locationDismissed by LocationCheck.carDismissed.collectAsState()
+            if (missing && bluetoothAudio && warn && !dismissed) PairCard(
+                title = "Bluetooth isn't connected",
+                body = "Music plays over Bluetooth, but your phone isn't connected to the car. " +
+                    "Connect it from the car's Bluetooth menu or your phone's.",
+                secondary = "Don't show again" to BluetoothAudioCheck::neverAgain,
+                primary = "OK" to BluetoothAudioCheck::dismissOnCar,
+            ) else if (locationOff && !locationDismissed) PairCard(
+                title = "Location is off",
+                body = "Map apps can't show where you are or give directions. Turn on location " +
+                    "in your phone's quick settings when you're parked.",
+                secondary = "Don't show again" to LocationCheck::neverAgain,
+                primary = "OK" to LocationCheck::dismissOnCar,
+            )
+        }
+        CarBluetooth.Prompt.ASK -> PairCard(
+            title = "Pair with this car?",
+            body = (if (bluetoothAudio) "Calls and music play" else "Calls play") +
+                " through the car's speakers once your phone and the car are paired. Your phone " +
+                "then asks you to confirm a code.",
+            secondary = "Not now" to CarBluetooth::notNow,
+            primary = "Pair" to CarBluetooth::pair,
+        )
+        CarBluetooth.Prompt.PAIRING -> PairCard(
+            title = "Confirm on your phone",
+            body = "Check the code on your phone and tap Pair. The car may ask too.",
+            secondary = null,
+            primary = "Hide" to CarBluetooth::hide,
+        )
+    }
+}
+
+@Composable
+private fun PairCard(title: String, body: String, secondary: Pair<String, () -> Unit>?, primary: Pair<String, () -> Unit>) {
+    Box(
+        Modifier.fillMaxSize().background(Color.Black.copy(alpha = 0.6f)).clickable(
+            indication = null,
+            interactionSource = remember { MutableInteractionSource() },
+            onClick = {},
+        ),
+        contentAlignment = Alignment.Center,
+    ) {
+        Surface(
+            shape = MaterialTheme.shapes.extraLarge,
+            color = MaterialTheme.colorScheme.surfaceContainerHigh,
+            modifier = Modifier.fillMaxWidth(0.85f).padding(16.dp),
+        ) {
+            Column(
+                Modifier.padding(32.dp),
+                verticalArrangement = Arrangement.spacedBy(20.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+            ) {
+                Text(title, style = MaterialTheme.typography.headlineSmall, fontWeight = FontWeight.Bold)
+                Text(
+                    body,
+                    style = MaterialTheme.typography.titleMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    textAlign = TextAlign.Center,
+                )
+                Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+                    secondary?.let { (label, onClick) ->
+                        GsButton(onClick = onClick, tone = GsTone.Outline, modifier = Modifier.weight(1f).height(56.dp)) {
+                            Text(label, style = MaterialTheme.typography.titleMedium)
+                        }
+                    }
+                    GsButton(onClick = primary.second, modifier = Modifier.weight(1f).height(56.dp)) {
+                        Text(primary.first, style = MaterialTheme.typography.titleMedium)
+                    }
+                }
+            }
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CalibrationApp.kt

@@ -1,89 +0,0 @@
-package app.seb3thehacker.gearslip.car
-
-import androidx.compose.foundation.Canvas
-import androidx.compose.foundation.background
-import androidx.compose.foundation.gestures.awaitEachGesture
-import androidx.compose.foundation.gestures.awaitFirstDown
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.material3.Button
-import androidx.compose.material3.Text
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.geometry.Offset
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.input.pointer.pointerInput
-import androidx.compose.ui.text.TextStyle
-import androidx.compose.ui.text.drawText
-import androidx.compose.ui.text.rememberTextMeasurer
-import androidx.compose.ui.unit.sp
-
-/**
- * Draws the raw video frame with pixel rulers, for measuring what the head unit actually shows.
- *
- * Numbers are frame pixels. Read the last number visible on each edge to see how much the head
- * unit crops there (the frame is 800 wide by 480 tall when the ruler runs to those values), and
- * tap anywhere: the crosshair is drawn where the phone believes the touch landed, so a mismatch
- * with your finger is the touch offset. Ignores vehicle insets on purpose.
- */
-@Composable
-fun CalibrationApp() {
-    val navigator = LocalCarNavigator.current
-    val measurer = rememberTextMeasurer()
-    var touch by remember { mutableStateOf<Offset?>(null) }
-
-    Box(
-        Modifier
-            .fillMaxSize()
-            .background(Color.Black)
-            .pointerInput(Unit) {
-                awaitEachGesture {
-                    val down = awaitFirstDown()
-                    touch = down.position
-                }
-            },
-    ) {
-        Canvas(Modifier.fillMaxSize()) {
-            val label = TextStyle(color = Color.White, fontSize = 11.sp)
-            val faint = Color(0x55FFFFFF)
-            val w = size.width
-            val h = size.height
-
-            var y = 0
-            while (y <= h) {
-                drawLine(if (y % 100 == 0) Color.White else faint, Offset(0f, y.toFloat()), Offset(w, y.toFloat()), strokeWidth = 1f)
-                if (y % 20 == 0) {
-                    drawText(measurer, "$y", Offset(2f, y.toFloat()), style = label)
-                    drawText(measurer, "$y", Offset(w - 30f, y.toFloat()), style = label)
-                }
-                y += 20
-            }
-            var x = 0
-            while (x <= w) {
-                drawLine(if (x % 100 == 0) Color.White else faint, Offset(x.toFloat(), 0f), Offset(x.toFloat(), h), strokeWidth = 1f)
-                if (x % 50 == 0 && x > 0) {
-                    drawText(measurer, "$x", Offset(x.toFloat() + 2f, 2f), style = label)
-                    drawText(measurer, "$x", Offset(x.toFloat() + 2f, h - 46f), style = label)
-                }
-                x += 20
-            }
-            // Frame border, drawn last and inset by 1px so it is the outermost thing that can show.
-            drawRect(Color.Red, topLeft = Offset(1f, 1f), size = androidx.compose.ui.geometry.Size(w - 2f, h - 2f), style = androidx.compose.ui.graphics.drawscope.Stroke(2f))
-            drawText(measurer, "frame ${w.toInt()}x${h.toInt()}", Offset(w / 2 - 50f, h / 2 - 60f), style = TextStyle(color = Color.Yellow, fontSize = 14.sp))
-
-            touch?.let { t ->
-                drawLine(Color.Green, Offset(t.x, 0f), Offset(t.x, h), strokeWidth = 2f)
-                drawLine(Color.Green, Offset(0f, t.y), Offset(w, t.y), strokeWidth = 2f)
-                drawText(measurer, "touch ${t.x.toInt()},${t.y.toInt()}", Offset(w / 2 - 50f, h / 2 + 40f), style = TextStyle(color = Color.Green, fontSize = 14.sp))
-            }
-        }
-        Button(onClick = { navigator.home() }, modifier = Modifier.align(Alignment.Center)) {
-            Text("Exit calibration")
-        }
-    }
-}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CallOverlay.kt

@@ -0,0 +1,134 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.shape.CircleShape
+import app.seb3thehacker.gearslip.car.theme.*
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Call
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.call.CallUiState
+import app.seb3thehacker.gearslip.call.CarCalls
+
+/**
+ * Sits above whatever the car is showing while a call is ringing or under way. Ringing takes the
+ * whole screen, because nothing else matters more right now; an active call is a thin band along
+ * the top, since from here the driver can only see who it is, not end it - see [CarCalls].
+ */
+@Composable
+fun CallOverlay(modifier: Modifier = Modifier) {
+    val state by CarCalls.state.collectAsState()
+    val context = LocalContext.current.applicationContext
+
+    when (val s = state) {
+        // Covers the box regardless of where the caller aligned it, so the alignment below is
+        // only ever felt by the active-call banner, which is the one that isn't full-screen.
+        is CallUiState.Ringing -> IncomingCall(s, onAnswer = { CarCalls.answer(context) }, onDecline = CarCalls::decline)
+        is CallUiState.Active -> ActiveCallBanner(s, modifier)
+        CallUiState.None -> {}
+    }
+}
+
+@Composable
+private fun IncomingCall(s: CallUiState.Ringing, onAnswer: () -> Unit, onDecline: () -> Unit) {
+    Surface(Modifier.fillMaxSize(), color = MaterialTheme.colorScheme.surfaceContainerLowest) {
+        Column(
+            Modifier.fillMaxSize().padding(32.dp),
+            horizontalAlignment = Alignment.CenterHorizontally,
+            verticalArrangement = Arrangement.Center,
+        ) {
+            Icon(
+                Icons.Filled.Call,
+                contentDescription = null,
+                modifier = Modifier.size(64.dp),
+                tint = MaterialTheme.colorScheme.primary,
+            )
+            Spacer(Modifier.height(16.dp))
+            Text(
+                "Incoming call",
+                style = MaterialTheme.typography.titleMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+            Spacer(Modifier.height(8.dp))
+            Text(
+                s.caller.label,
+                style = MaterialTheme.typography.displaySmall,
+                fontWeight = FontWeight.Bold,
+                textAlign = TextAlign.Center,
+            )
+            Spacer(Modifier.height(56.dp))
+            Row(horizontalArrangement = Arrangement.spacedBy(48.dp)) {
+                CallButton(Icons.Filled.Close, "Decline", MaterialTheme.colorScheme.error, enabled = s.canDecline, onClick = onDecline)
+                CallButton(Icons.Filled.Call, "Answer", MaterialTheme.colorScheme.primary, enabled = true, onClick = onAnswer)
+            }
+            if (!s.canDecline) {
+                Spacer(Modifier.height(20.dp))
+                Text(
+                    "Already ringing out loud - answer here, or let it ring.",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun CallButton(icon: ImageVector, label: String, color: Color, enabled: Boolean, onClick: () -> Unit) {
+    Column(horizontalAlignment = Alignment.CenterHorizontally) {
+        GsIconButton(
+            icon, label, onClick,
+            colors = GsColors(color, Color.White),
+            enabled = enabled,
+            size = 72.dp,
+            iconSize = 30.dp,
+            shape = CircleShape,
+        )
+        Spacer(Modifier.height(8.dp))
+        Text(label, style = MaterialTheme.typography.labelLarge)
+    }
+}
+
+@Composable
+private fun ActiveCallBanner(s: CallUiState.Active, modifier: Modifier = Modifier) {
+    Surface(
+        color = MaterialTheme.colorScheme.primaryContainer,
+        contentColor = MaterialTheme.colorScheme.onPrimaryContainer,
+        modifier = modifier.fillMaxWidth(),
+    ) {
+        Row(
+            Modifier.padding(horizontal = 20.dp, vertical = 10.dp),
+            horizontalArrangement = Arrangement.Center,
+        ) {
+            Icon(Icons.Filled.Call, contentDescription = null, modifier = Modifier.size(20.dp))
+            Spacer(Modifier.height(0.dp))
+            Text(
+                "  On a call" + (s.caller?.let { " with ${it.label}" } ?: ""),
+                style = MaterialTheme.typography.labelLarge,
+                fontWeight = FontWeight.SemiBold,
+            )
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarAppStage.kt

@@ -1,9 +1,15 @@
 package app.seb3thehacker.gearslip.car
 
+import app.seb3thehacker.gearslip.car.theme.*
 import android.view.SurfaceHolder
 import android.view.SurfaceView
 import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.gestures.detectTransformGestures
+import androidx.compose.foundation.gestures.awaitEachGesture
+import androidx.compose.foundation.gestures.awaitFirstDown
+import androidx.compose.ui.input.pointer.PointerEventPass
+import androidx.compose.ui.input.pointer.util.VelocityTracker
+import kotlin.math.hypot
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -13,11 +19,11 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
-import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
@@ -60,7 +66,6 @@ fun CarAppStage(
             AppSurface(connection, frame, template, Modifier.fillMaxSize())
         }
         TemplateChrome(template, Modifier.fillMaxSize().padding(top = if (embedded) 0.dp else CHROME_BAR))
-        if (embedded) CornerMask(EMBEDDED_RADIUS, MaterialTheme.colorScheme.background)
         if (!embedded) ChromeBar(status, onDisconnect, Modifier.align(Alignment.TopCenter))
     }
 }
@@ -90,6 +95,29 @@ private fun AppSurface(
         }
     }
 
+    // A fresh SurfaceView - and so a fresh Surface - for every size, the way Android Auto hands an
+    // app a new surface rather than resizing the old one. A resized SurfaceView keeps the same
+    // BufferQueue, and apps that draw through their own VirtualDisplay build the
+    // new one on it before releasing the old: the old display's disconnect then takes the new one's
+    // connection with it and the map freezes for good. The nav bar hiding for the search keyboard
+    // and the lyrics pane opening both resize this area.
+    androidx.compose.foundation.layout.BoxWithConstraints(modifier) {
+        val epoch by connection.surfaceEpoch.collectAsState()
+        androidx.compose.runtime.key(constraints.maxWidth, constraints.maxHeight, epoch) {
+            SurfaceHost(connection, frame, onSize = { size = it }, Modifier.fillMaxSize())
+        }
+    }
+
+    DisposableEffect(connection) { onDispose { connection.detachSurface() } }
+}
+
+@Composable
+private fun SurfaceHost(
+    connection: CarAppConnection,
+    frame: CarEnvironment.Frame,
+    onSize: (Pair<Int, Int>) -> Unit,
+    modifier: Modifier,
+) {
     AndroidView(
         modifier = modifier
             .pointerInput(connection) {
@@ -102,6 +130,30 @@ private fun AppSurface(
                     if (pan != Offset.Zero) connection.surfaceScroll(-pan.x, -pan.y)
                     if (zoom != 1f) connection.surfaceScale(centroid.x, centroid.y, zoom)
                 }
+            }
+            .pointerInput(connection) {
+                // detectTransformGestures has no velocity, so a fling is measured here alongside
+                // it: one finger lifting while still moving lets the map glide on, as on a car.
+                // Velocity is the finger's own, which is GestureDetector's onFling convention.
+                awaitEachGesture {
+                    val down = awaitFirstDown(requireUnconsumed = false)
+                    val tracker = VelocityTracker()
+                    tracker.addPosition(down.uptimeMillis, down.position)
+                    var pinched = false
+                    while (true) {
+                        val event = awaitPointerEvent(PointerEventPass.Final)
+                        if (event.changes.size > 1) pinched = true
+                        val change = event.changes.firstOrNull { it.id == down.id } ?: break
+                        tracker.addPosition(change.uptimeMillis, change.position)
+                        if (!change.pressed) {
+                            val v = tracker.calculateVelocity()
+                            if (!pinched && hypot(v.x, v.y) >= FLING_MIN_PX_S) {
+                                connection.surfaceFling(v.x, v.y)
+                            }
+                            break
+                        }
+                    }
+                }
             },
         factory = { context ->
             SurfaceView(context).apply {
@@ -115,20 +167,20 @@ private fun AppSurface(
                         height: Int,
                     ) {
                         GearslipLog.i("stage: surface ready at ${width}x$height")
-                        size = width to height
+                        onSize(width to height)
                         connection.attachSurface(holder.surface, width, height, frame.densityDpi)
                     }
 
                     override fun surfaceDestroyed(holder: SurfaceHolder) {
                         GearslipLog.i("stage: surface destroyed")
-                        connection.detachSurface()
+                        // Only this view's own surface: a replaced view's teardown can land after
+                        // its successor has already lent the app a new one.
+                        connection.detachSurface(holder.surface)
                     }
                 })
             }
         },
     )
-
-    DisposableEffect(connection) { onDispose { connection.detachSurface() } }
 }
 
 @Composable
@@ -158,34 +210,13 @@ private fun ChromeBar(
                 }.joinToString(" - ")
                 Text(detail, style = MaterialTheme.typography.bodySmall)
             }
-            TextButton(onClick = onDisconnect) { Text("Stop", color = Color.White) }
+            GsButton(onClick = onDisconnect, tone = GsTone.Tonal) { Text("Stop") }
         }
     }
 }
 
-/** Corner radius of the home screen's map pane and player. */
-val EMBEDDED_RADIUS = 18.dp
-
-/**
- * Rounds the corners of a SurfaceView, which Compose cannot clip: the app draws into its own
- * layer, so the corners are covered from above with the surrounding colour instead.
- */
-@Composable
-private fun CornerMask(radius: androidx.compose.ui.unit.Dp, color: Color) {
-    androidx.compose.foundation.Canvas(Modifier.fillMaxSize()) {
-        val bounds = androidx.compose.ui.geometry.Rect(0f, 0f, size.width, size.height)
-        val cut = androidx.compose.ui.graphics.Path().apply {
-            addRect(bounds)
-            addRoundRect(
-                androidx.compose.ui.geometry.RoundRect(
-                    bounds, androidx.compose.ui.geometry.CornerRadius(radius.toPx()),
-                ),
-            )
-            fillType = androidx.compose.ui.graphics.PathFillType.EvenOdd
-        }
-        drawPath(cut, color)
-    }
-}
-
 /** Height of [ChromeBar]; the template's own chrome starts below it. */
 private val CHROME_BAR = 44.dp
+
+/** Slower than this when the finger lifts and it was a drag that stopped, not a fling. */
+private const val FLING_MIN_PX_S = 400f

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarApps.kt

@@ -1,7 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.Info
+import androidx.compose.material.icons.filled.Call
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material.icons.filled.Share
 import androidx.compose.material.icons.filled.Settings
@@ -22,14 +22,14 @@ class CarApp(
 object CarApps {
 
     val all: List<CarApp> = listOf(
-        CarApp("web", "Web", Icons.Filled.Search) {
+        CarApp("web", "Browser", Icons.Filled.Search) {
             WebApp(content = ProjectedContent.resolve(LocalContext.current))
         },
         CarApp("phone", "Screen sharing", Icons.Filled.Share) {
             PhoneAppsScreen()
         },
-        CarApp("calibrate", "Display test", Icons.Filled.Info) {
-            CalibrationApp()
+        CarApp("dialer", "Phone", Icons.Filled.Call) {
+            PhoneDialerScreen()
         },
         CarApp("settings", "Settings", Icons.Filled.Settings) {
             CarSettingsScreen()

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarAssistant.kt

@@ -0,0 +1,276 @@
+package app.seb3thehacker.gearslip.car
+
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
+import android.speech.RecognitionListener
+import android.speech.RecognizerIntent
+import android.speech.SpeechRecognizer
+import android.speech.tts.TextToSpeech
+import android.speech.tts.UtteranceProgressListener
+import androidx.core.content.ContextCompat
+import app.seb3thehacker.gearslip.call.CallUiState
+import app.seb3thehacker.gearslip.call.CarCalls
+import app.seb3thehacker.gearslip.speech.SpeechEngine
+import app.seb3thehacker.gearslip.speech.VoiceFocus
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * A voice assistant: Gearslip's own [SpeechEngine] (whisper.cpp) to listen, the system's
+ * [TextToSpeech] to answer. Listening used to go through the system's [SpeechRecognizer] alone,
+ * but many phones have no recognizer at all (GrapheneOS ships only text-to-speech), so the
+ * system one is now just the fallback for when the bundled engine can't run.
+ *
+ * Listening and speaking live here; deciding what a command *means* is [AssistantCommands], kept
+ * separate because it needs a [CarNavigator] and a frame to act on, neither of which this object
+ * has - see [pendingCommand].
+ */
+object CarAssistant {
+
+    enum class Phase { IDLE, LISTENING, THINKING, SPEAKING, ERROR }
+
+    data class State(
+        val phase: Phase = Phase.IDLE,
+        val heard: String = "",
+        val reply: String = "",
+        val missingPermission: Boolean = false,
+        /** False from the press until the microphone is actually open, so the overlay doesn't claim to listen early. */
+        val ready: Boolean = false,
+    )
+
+    private val _state = MutableStateFlow(State())
+    val state: StateFlow<State> = _state
+
+    /** Set once a recognition result comes in; [reply] clears it once handled. */
+    private val _pendingCommand = MutableStateFlow<String?>(null)
+    val pendingCommand: StateFlow<String?> = _pendingCommand
+
+    private var appContext: Context? = null
+    private var recognizer: SpeechRecognizer? = null
+    private var tts: TextToSpeech? = null
+    private var ttsReady = false
+
+    fun init(context: Context) {
+        appContext = context.applicationContext
+        if (tts != null) return
+        tts = TextToSpeech(appContext) { status -> ttsReady = status == TextToSpeech.SUCCESS }
+    }
+
+    private val mainHandler = Handler(Looper.getMainLooper())
+
+    /**
+     * Starts listening, or does nothing if the assistant is already busy with the last request.
+     * [SpeechRecognizer] must be driven from a thread with a Looper, but this is also called from
+     * the raw wire-protocol worker thread ([GearslipRunner]'s key-event handling for the head
+     * unit's own PTT button) which has none - so this always hops to the main thread itself
+     * rather than asking every caller to remember to.
+     */
+    fun start() {
+        if (Looper.myLooper() == Looper.getMainLooper()) startOnMainThread() else mainHandler.post(::startOnMainThread)
+    }
+
+    private fun startOnMainThread() {
+        val context = appContext ?: return
+        if (_state.value.phase == Phase.LISTENING || _state.value.phase == Phase.THINKING) return
+
+        if (ContextCompat.checkSelfPermission(context, android.Manifest.permission.RECORD_AUDIO) !=
+            PackageManager.PERMISSION_GRANTED
+        ) {
+            _state.value = State(Phase.ERROR, reply = "Needs the microphone permission.", missingPermission = true)
+            return
+        }
+        // Android hands every app but the dialer a silent microphone during a call.
+        if (CarCalls.state.value is CallUiState.Active) {
+            _state.value = State(Phase.ERROR, reply = "Voice commands work once the call ends.")
+            return
+        }
+        tts?.stop()
+        _state.value = State(Phase.LISTENING)
+        listenOnce(
+            onListening = { _state.value = _state.value.copy(ready = true) },
+            onPartial = { text -> _state.value = _state.value.copy(heard = text) },
+            onHeard = { _state.value = _state.value.copy(phase = Phase.THINKING) },
+            onResult = { text ->
+                _state.value = _state.value.copy(phase = Phase.THINKING, heard = text)
+                _pendingCommand.value = text
+            },
+            onError = { message -> _state.value = State(Phase.ERROR, reply = message) },
+        )
+    }
+
+    /** Closes the overlay from wherever it's showing: mid-listen, mid-think, or after speaking. */
+    fun cancel() {
+        releaseRecognizer()
+        tts?.stop()
+        _pendingCommand.value = null
+        _state.value = State(Phase.IDLE)
+    }
+
+    /**
+     * Called once [pendingCommand] has been turned into an answer - from [CarUi], the one place
+     * that actually has a [CarNavigator] to have acted on it with.
+     */
+    fun reply(text: String) {
+        _pendingCommand.value = null
+        _state.value = _state.value.copy(phase = Phase.SPEAKING, reply = text)
+
+        val engine = tts
+        if (engine == null || !ttsReady || text.isBlank()) {
+            _state.value = _state.value.copy(phase = Phase.IDLE)
+            return
+        }
+        appContext?.let(VoiceFocus::acquire)
+        engine.setOnUtteranceProgressListener(object : UtteranceProgressListener() {
+            override fun onStart(utteranceId: String?) {}
+            override fun onDone(utteranceId: String?) {
+                VoiceFocus.release()
+                _state.value = _state.value.copy(phase = Phase.IDLE)
+            }
+            @Deprecated("Deprecated in Java, no replacement on this API level")
+            override fun onError(utteranceId: String?) {
+                VoiceFocus.release()
+                _state.value = _state.value.copy(phase = Phase.IDLE)
+            }
+            override fun onStop(utteranceId: String?, interrupted: Boolean) { VoiceFocus.release() }
+        })
+        engine.speak(text, TextToSpeech.QUEUE_FLUSH, null, "gearslip-assistant")
+    }
+
+    /**
+     * Speaks [text] for someone other than the assistant (a message read aloud), then runs
+     * [onDone] on the main thread - straight away if speech isn't available.
+     */
+    fun say(text: String, onDone: () -> Unit) {
+        val engine = tts
+        val context = appContext
+        if (engine == null || context == null || !ttsReady || text.isBlank()) {
+            mainHandler.post(onDone)
+            return
+        }
+        VoiceFocus.acquire(context)
+        engine.setOnUtteranceProgressListener(object : UtteranceProgressListener() {
+            override fun onStart(utteranceId: String?) {}
+            override fun onDone(utteranceId: String?) { VoiceFocus.release(); mainHandler.post(onDone) }
+            @Deprecated("Deprecated in Java, no replacement on this API level")
+            override fun onError(utteranceId: String?) { VoiceFocus.release(); mainHandler.post(onDone) }
+            // Stopped part way: whoever stopped it has already moved on.
+            override fun onStop(utteranceId: String?, interrupted: Boolean) { VoiceFocus.release() }
+        })
+        engine.speak(text, TextToSpeech.QUEUE_FLUSH, null, "gearslip-say")
+    }
+
+    fun stopSpeaking() { tts?.stop() }
+
+    /**
+     * Listens once, the same way the assistant does, and hands back what was said without acting
+     * on it. Callbacks arrive on the main thread; [onError] gets a sentence fit to show.
+     */
+    fun dictate(
+        onPartial: (String) -> Unit,
+        onResult: (String) -> Unit,
+        onError: (String) -> Unit,
+        cue: Boolean = true,
+        onSpeaking: () -> Unit = {},
+    ) {
+        cancel()
+        listenOnce(onPartial, onHeard = {}, onResult = onResult, onError = onError, cue = cue, onSpeaking = onSpeaking)
+    }
+
+    /**
+     * One phrase, through Gearslip's own [SpeechEngine], or the phone's recognizer when the driver
+     * chose it in settings. Never the phone's on its own: on most phones that's Google's.
+     */
+    private fun listenOnce(
+        onPartial: (String) -> Unit,
+        onListening: () -> Unit = {},
+        onHeard: () -> Unit,
+        onResult: (String) -> Unit,
+        onError: (String) -> Unit,
+        cue: Boolean = true,
+        onSpeaking: () -> Unit = {},
+    ) {
+        val context = appContext ?: return onError("Speech isn't ready yet.")
+        if (CarSettings.systemSpeech.value && SpeechRecognizer.isRecognitionAvailable(context)) {
+            return systemListen(context, onListening, onPartial, onHeard, onResult, onError)
+        }
+        SpeechEngine.listen(
+            context,
+            cue = cue,
+            onSpeaking = onSpeaking,
+            onPartial = onPartial,
+            onListening = onListening,
+            onHeard = onHeard,
+            onResult = onResult,
+            onError = onError,
+        )
+    }
+
+    private fun systemListen(
+        context: Context,
+        onListening: () -> Unit,
+        onPartial: (String) -> Unit,
+        onHeard: () -> Unit,
+        onResult: (String) -> Unit,
+        onError: (String) -> Unit,
+    ) {
+        val r = SpeechRecognizer.createSpeechRecognizer(context)
+        recognizer = r
+        r.setRecognitionListener(object : RecognitionListener {
+            override fun onReadyForSpeech(params: Bundle?) = onListening()
+            override fun onBeginningOfSpeech() {}
+            override fun onRmsChanged(rmsdB: Float) {}
+            override fun onBufferReceived(buffer: ByteArray?) {}
+            override fun onEndOfSpeech() = onHeard()
+            override fun onEvent(eventType: Int, params: Bundle?) {}
+
+            override fun onError(error: Int) {
+                releaseRecognizer()
+                onError(errorMessage(error))
+            }
+
+            override fun onResults(results: Bundle?) {
+                releaseRecognizer()
+                val text = results?.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION)?.firstOrNull().orEmpty()
+                if (text.isBlank()) onError("Didn't catch that.") else onResult(text)
+            }
+
+            override fun onPartialResults(partialResults: Bundle?) {
+                partialResults?.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION)?.firstOrNull()?.let(onPartial)
+            }
+        })
+        r.startListening(
+            Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH).apply {
+                putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, RecognizerIntent.LANGUAGE_MODEL_FREE_FORM)
+                putExtra(RecognizerIntent.EXTRA_PARTIAL_RESULTS, true)
+                putExtra(RecognizerIntent.EXTRA_CALLING_PACKAGE, context.packageName)
+            },
+        )
+    }
+
+    fun stopListening() = releaseRecognizer()
+
+    private fun releaseRecognizer() {
+        SpeechEngine.cancel()
+        recognizer?.let { runCatching { it.cancel() }; it.destroy() }
+        recognizer = null
+    }
+
+    private fun errorMessage(code: Int): String = when (code) {
+        SpeechRecognizer.ERROR_NO_MATCH, SpeechRecognizer.ERROR_SPEECH_TIMEOUT -> "Didn't catch that."
+        SpeechRecognizer.ERROR_INSUFFICIENT_PERMISSIONS -> "Needs the microphone permission."
+        SpeechRecognizer.ERROR_RECOGNIZER_BUSY -> "The speech recognizer is busy."
+        SpeechRecognizer.ERROR_NETWORK, SpeechRecognizer.ERROR_NETWORK_TIMEOUT -> "The speech recognizer needs a network it doesn't have."
+        else -> "Speech recognition failed."
+    }
+
+    fun shutdown() {
+        releaseRecognizer()
+        tts?.shutdown()
+        tts = null
+        ttsReady = false
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarBluetooth.kt

@@ -0,0 +1,255 @@
+package app.seb3thehacker.gearslip.car
+
+import android.Manifest
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothDevice
+import android.bluetooth.BluetoothManager
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.content.pm.PackageManager
+import android.os.Handler
+import android.os.Looper
+import androidx.car.app.CarToast
+import app.seb3thehacker.gearslip.AppSettings
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.Protobuf
+import app.seb3thehacker.gearslip.ServiceDiscovery
+import app.seb3thehacker.gearslip.Wire
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import java.security.MessageDigest
+
+/**
+ * Pairs the phone with the car over Bluetooth the first time they meet, so calls (and music, when
+ * the driver chose Bluetooth audio) reach the car's speakers. Android Auto does this on its own;
+ * Gearslip asks first, on the car screen.
+ *
+ * The car names its Bluetooth address in its service list. When the driver taps Pair, Gearslip
+ * opens the car's Bluetooth channel and sends what Android Auto sends:
+ *
+ *   -> CHANNEL_OPEN_REQUEST                 <- CHANNEL_OPEN_RESPONSE
+ *   -> PairingRequest { phone_address, method }
+ *   <- PairingResponse { status, already_paired }
+ *
+ * then starts pairing from the phone. Two things Android Auto has that Gearslip can't: the
+ * phone's own Bluetooth address (apps get a placeholder), and confirming the pairing code without
+ * asking. So a car may turn the request down, and the phone always shows its pairing dialog. The
+ * channel stays closed unless the driver taps Pair: every new channel is a risk to cars that work.
+ */
+object CarBluetooth {
+
+    enum class Prompt { NONE, ASK, PAIRING }
+
+    private val _prompt = MutableStateFlow(Prompt.NONE)
+    val prompt: StateFlow<Prompt> = _prompt
+
+    private val log = GearslipLog.tagged("bluetooth")
+    private val main = Handler(Looper.getMainLooper())
+    private var appContext: Context? = null
+
+    /** This session's car: its channel, and how to open and write to it. */
+    private class Car(
+        val service: ServiceDiscovery.BluetoothService,
+        val open: () -> Unit,
+        val send: (messageId: Int, body: ByteArray) -> Unit,
+    )
+
+    @Volatile private var car: Car? = null
+    @Volatile private var bondStarted = false
+    /** From the Pair tap until it succeeds or fails, whether or not the card still shows. */
+    @Volatile private var pairing = false
+    private var receiver: BroadcastReceiver? = null
+
+    /** The car's Bluetooth address, when it named one in its service list. */
+    val carAddress: String? get() = car?.service?.carAddress
+
+    /** The car's Bluetooth channel once the driver has asked to pair, -1 otherwise. */
+    val channelId: Int get() = car?.takeIf { pairing }?.service?.serviceId ?: -1
+
+    fun init(context: Context) {
+        appContext = context.applicationContext
+    }
+
+    /** Called once the car lists its services. Asks on the car screen only if there's pairing to do. */
+    fun onCarConnected(
+        service: ServiceDiscovery.BluetoothService,
+        open: () -> Unit,
+        send: (messageId: Int, body: ByteArray) -> Unit,
+    ) {
+        car = Car(service, open, send)
+        bondStarted = false
+        log.i("the car offers Bluetooth pairing, methods=${service.pairingMethods}")
+        val device = device() ?: return
+        when {
+            device.bondState == BluetoothDevice.BOND_BONDED -> log.i("already paired with this car")
+            declined(service.carAddress) -> log.i("not paired, and the driver said not now for this car")
+            else -> _prompt.value = Prompt.ASK
+        }
+    }
+
+    fun onCarDisconnected() {
+        car = null
+        pairing = false
+        main.post {
+            stopWatching()
+            _prompt.value = Prompt.NONE
+        }
+    }
+
+    /** The driver tapped Pair. */
+    fun pair() {
+        val c = car ?: return
+        val device = device() ?: return
+        pairing = true
+        _prompt.value = Prompt.PAIRING
+        watchBonding(device)
+        c.open()
+        log.i("-> ChannelOpenRequest on channel ${c.service.serviceId}")
+        // If the car never answers on its channel, pair from the phone anyway.
+        main.postDelayed({ startBond("the car didn't answer the pairing request") }, CAR_REPLY_WAIT_MS)
+        main.postDelayed({
+            if (pairing) finish("Pairing didn't finish. Pair from the car's Bluetooth menu instead.")
+        }, GIVE_UP_MS)
+    }
+
+    /** The driver tapped Not now: this car isn't asked about again. */
+    fun notNow() {
+        car?.service?.carAddress?.let { address ->
+            val context = appContext ?: return@let
+            val list = AppSettings.getString(context, KEY_DECLINED, "").split(",").filter { it.isNotEmpty() }
+            AppSettings.putString(context, KEY_DECLINED, (list + hash(address)).distinct().joinToString(","))
+        }
+        _prompt.value = Prompt.NONE
+    }
+
+    /** Hides the pairing card. The phone's own dialog carries on. */
+    fun hide() {
+        _prompt.value = Prompt.NONE
+    }
+
+    fun onMessage(messageId: Int, body: ByteArray) {
+        val c = car ?: return
+        when (messageId) {
+            MSG_CHANNEL_OPEN_RESPONSE -> {
+                val status = Protobuf.readInt32Field(body, 1) ?: 0
+                log.i("<- ChannelOpenResponse: status=$status")
+                if (status != 0) {
+                    main.post { startBond("the car wouldn't open its Bluetooth channel") }
+                    return
+                }
+                val method = c.service.pairingMethods.firstOrNull { it == METHOD_NUMERIC_COMPARISON }
+                    ?: c.service.pairingMethods.firstOrNull() ?: METHOD_NUMERIC_COMPARISON
+                c.send(
+                    MSG_PAIRING_REQUEST,
+                    Protobuf.stringField(1, phoneAddress()) + Protobuf.varintField(2, method.toLong()),
+                )
+                log.i("-> PairingRequest(method=$method)")
+            }
+            MSG_PAIRING_RESPONSE -> {
+                val fields = Wire.fields(body)
+                log.i("<- PairingResponse status=${Wire.varint(fields, 1)} already_paired=${Wire.varint(fields, 2) == 1L}")
+                // Some cars start pairing themselves once they answer; give them a moment first.
+                main.postDelayed({ startBond("the car answered") }, CAR_BOND_WAIT_MS)
+            }
+            // Carries the pairing code. Android shows it to the driver, so it stays out of the log.
+            MSG_AUTHENTICATION_DATA -> log.i("<- AuthenticationData (${body.size} bytes)")
+            else -> log.i("<- unhandled message id=$messageId (${body.size} bytes)")
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    private fun startBond(why: String) {
+        if (bondStarted || !pairing) return
+        val device = device() ?: return
+        if (device.bondState != BluetoothDevice.BOND_NONE) return
+        bondStarted = true
+        val started = runCatching { device.createBond() }.getOrDefault(false)
+        log.i("pairing from the phone ($why): ${if (started) "started" else "refused"}")
+        if (!started) finish("Pairing didn't start. Pair from the car's Bluetooth menu instead.")
+    }
+
+    private fun watchBonding(device: BluetoothDevice) {
+        val context = appContext ?: return
+        stopWatching()
+        val r = object : BroadcastReceiver() {
+            @Suppress("DEPRECATION")
+            override fun onReceive(context: Context, intent: Intent) {
+                val changed = intent.getParcelableExtra<BluetoothDevice>(BluetoothDevice.EXTRA_DEVICE) ?: return
+                if (changed.address != device.address) return
+                val state = intent.getIntExtra(BluetoothDevice.EXTRA_BOND_STATE, BluetoothDevice.BOND_NONE)
+                val previous = intent.getIntExtra(BluetoothDevice.EXTRA_PREVIOUS_BOND_STATE, BluetoothDevice.BOND_NONE)
+                log.i("bond state $previous -> $state")
+                when {
+                    state == BluetoothDevice.BOND_BONDING -> bondStarted = true
+                    state == BluetoothDevice.BOND_BONDED -> finish("Paired. Calls now play through the car.")
+                    previous == BluetoothDevice.BOND_BONDING -> finish("Pairing didn't finish. Pair from the car's Bluetooth menu instead.")
+                }
+            }
+        }
+        context.registerReceiver(r, IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED), Context.RECEIVER_EXPORTED)
+        receiver = r
+    }
+
+    private fun finish(message: String) {
+        pairing = false
+        stopWatching()
+        main.removeCallbacksAndMessages(null)
+        _prompt.value = Prompt.NONE
+        CarToasts.show(this, message, CarToast.LENGTH_LONG)
+    }
+
+    private fun stopWatching() {
+        val r = receiver ?: return
+        receiver = null
+        runCatching { appContext?.unregisterReceiver(r) }
+    }
+
+    /** The car as a Bluetooth device, or null (and logged) when Gearslip can't reach Bluetooth. */
+    private fun device(): BluetoothDevice? {
+        val context = appContext ?: return null
+        val address = car?.service?.carAddress ?: return null
+        if (context.checkSelfPermission(Manifest.permission.BLUETOOTH_CONNECT) != PackageManager.PERMISSION_GRANTED) {
+            log.i("can't check pairing: the Bluetooth permission isn't granted")
+            return null
+        }
+        val adapter = context.getSystemService(BluetoothManager::class.java)?.adapter
+        if (adapter == null || !adapter.isEnabled) {
+            log.i("can't check pairing: Bluetooth is off")
+            return null
+        }
+        if (!BluetoothAdapter.checkBluetoothAddress(address)) {
+            log.w("the car sent an address that isn't one")
+            return null
+        }
+        return adapter.getRemoteDevice(address)
+    }
+
+    /** Apps get 02:00:00:00:00:00 here, not the real address. Sent anyway, as the field is required. */
+    @SuppressLint("MissingPermission", "HardwareIds")
+    private fun phoneAddress(): String =
+        runCatching { appContext?.getSystemService(BluetoothManager::class.java)?.adapter?.address }.getOrNull()
+            ?: "02:00:00:00:00:00"
+
+    private fun declined(address: String): Boolean {
+        val context = appContext ?: return false
+        return hash(address) in AppSettings.getString(context, KEY_DECLINED, "").split(",")
+    }
+
+    /** Settings keep a short hash, not the car's address. */
+    private fun hash(address: String): String =
+        MessageDigest.getInstance("SHA-256").digest(address.uppercase().toByteArray())
+            .take(8).joinToString("") { "%02x".format(it) }
+
+    private const val KEY_DECLINED = "bluetooth_pair_declined"
+    private const val CAR_REPLY_WAIT_MS = 5_000L
+    private const val CAR_BOND_WAIT_MS = 3_000L
+    private const val GIVE_UP_MS = 90_000L
+    private const val METHOD_NUMERIC_COMPARISON = 2
+    private const val MSG_CHANNEL_OPEN_RESPONSE = 8
+    private const val MSG_PAIRING_REQUEST = 32769
+    private const val MSG_PAIRING_RESPONSE = 32770
+    private const val MSG_AUTHENTICATION_DATA = 32771
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarDashboardScreen.kt

@@ -22,7 +22,8 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.produceState
-import androidx.compose.foundation.clickable
+import app.seb3thehacker.gearslip.car.theme.GsColors
+import app.seb3thehacker.gearslip.car.theme.GsIconBox
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
@@ -43,7 +44,8 @@ import kotlinx.coroutines.withContext
 import org.json.JSONObject
 
 /**
- * Opened from the nav bar clock: the week's calendar and the current weather, at a glance. Both
+ * Opened from the nav bar clock: the current weather, the week's calendar and the phone's
+ * notifications, at a glance. The first two
  * need permissions granted on the phone (READ_CALENDAR, location) - if either was declined
  * this just shows an empty state instead of asking again from inside the car UI.
  */
@@ -58,9 +60,10 @@ fun CarDashboardScreen() {
             .padding(horizontal = 24.dp, vertical = 16.dp),
         verticalArrangement = Arrangement.spacedBy(24.dp),
     ) {
-        Text("Today", style = MaterialTheme.typography.headlineMedium, fontWeight = FontWeight.Bold)
+        ScreenHeader("Today")
         WeatherCard(context)
         AgendaCard(context)
+        NotificationsSection()
     }
 }
 
@@ -70,10 +73,10 @@ private fun WeatherCard(context: Context) {
     val navigator = LocalCarNavigator.current
     LaunchedEffect(Unit) { Weather.refresh(context) }
 
-    Surface(
-        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+    GsIconBox(
+        onClick = { navigator.weather() },
+        colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHigh, MaterialTheme.colorScheme.onSurface),
         shape = MaterialTheme.shapes.extraLarge,
-        modifier = Modifier.clickable { navigator.weather() },
     ) {
         Row(
             Modifier.fillMaxWidth().padding(20.dp),

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarHomeScreen.kt

@@ -1,10 +1,9 @@
 package app.seb3thehacker.gearslip.car
 
-import androidx.compose.foundation.Image
+import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxHeight
@@ -13,46 +12,63 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.layout.width
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.PlayArrow
-import androidx.compose.material3.FilledIconButton
-import androidx.compose.material3.FilledTonalButton
-import androidx.compose.material3.Icon
-import androidx.compose.material3.IconButton
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Surface
-import androidx.compose.material3.Text
-import androidx.compose.material3.TextButton
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
+import androidx.compose.material.icons.filled.Favorite
+import androidx.compose.material.icons.filled.FavoriteBorder
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.res.vectorResource
+import android.support.v4.media.session.PlaybackStateCompat
+import app.seb3thehacker.gearslip.R
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.runtime.mutableLongStateOf
 import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.ui.draw.clip
-import android.media.session.PlaybackState
 import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.LocalContext
+import android.media.session.PlaybackState
+import app.seb3thehacker.gearslip.media.MediaArt
+import kotlinx.coroutines.delay
+import androidx.compose.material3.Icon
+import androidx.compose.animation.animateColorAsState
+import androidx.compose.animation.core.tween
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.luminance
+import app.seb3thehacker.gearslip.media.ArtColor
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import app.seb3thehacker.gearslip.host.CarAppConnection
 import app.seb3thehacker.gearslip.media.CarMedia
-import app.seb3thehacker.gearslip.media.MediaArt
-import kotlinx.coroutines.delay
+import app.seb3thehacker.gearslip.media.NowPlaying
+import kotlinx.coroutines.launch
 
 /**
- * The home screen: the map on the left, what is playing on the right.
+ * The home screen: the map on the left, the docked player on the right when asked for.
  *
- * The map is whatever navigation app was used last, brought back on its own. The player only
- * takes its share of the screen only while something is playing or paused; otherwise the map has all of it.
+ * The map is whatever navigation app was used last, brought back on its own. The player sits in
+ * the nav bar's pill until its dock button moves it here; the column closes itself back to a
+ * full-width map once nothing is playing.
  */
 @Composable
 fun CarHome() {
@@ -65,21 +81,35 @@ fun CarHome() {
     LaunchedEffect(phase) { if (phase == CarMedia.Phase.READY) CarServices.autoplayIfDue() }
 
     val navigator = LocalCarNavigator.current
-    val showPlayer = phase == CarMedia.Phase.READY && now.isActive && !navigator.playerMinimised
-    // Once playback ends there is nothing left to minimise; the next song starts in place.
-    LaunchedEffect(now.isActive) { if (!now.isActive) navigator.restorePlayer() }
+    val panel = navigator.sidePanel
 
-    Row(Modifier.fillMaxSize().padding(8.dp), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+    // Coming back to the map from another screen: the map stayed loaded underneath, so its surface
+    // is only replaced if it died meanwhile. The first composition is skipped, since the surface
+    // is only just being lent.
+    val onHome = navigator.current == CarScreen.Home
+    val seenHome = remember { booleanArrayOf(false) }
+    LaunchedEffect(onHome) {
+        if (onHome && seenHome[0]) CarServices.nav.replaceDeadSurface()
+        if (onHome) seenHome[0] = true
+    }
+    val splitScreen = phase == CarMedia.Phase.READY && now.isActive && panel != SidePanel.NONE
+
+    // No outer padding on any side, split screen or not - only the gap between the two panes
+    // when the player is sharing the screen with the map.
+    Row(
+        Modifier.fillMaxSize(),
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
         Box(
             Modifier
-                .weight(if (showPlayer) 2.1f else 1f)
-                .fillMaxHeight()
-                .clip(RoundedCornerShape(EMBEDDED_RADIUS)),
+                .weight(if (splitScreen) 2.1f else 1f)
+                .fillMaxHeight(),
         ) {
             MapPane(navStatus, frame)
         }
-        if (showPlayer) {
-            MiniPlayer(Modifier.weight(1f).fillMaxHeight())
+        if (splitScreen) {
+            val side = Modifier.weight(1f).fillMaxHeight()
+            if (panel == SidePanel.LYRICS) SideLyrics(now, side) else DockedPlayer(now, side)
         }
     }
 }
@@ -98,119 +128,131 @@ private fun MapPane(status: CarAppConnection.Status, frame: CarEnvironment.Frame
         horizontalAlignment = Alignment.CenterHorizontally,
     ) {
         val hasLast = CarSettings.lastNav.value != null
+        val hasNavApps by CarServices.hasNavApps.collectAsStateWithLifecycle()
+        val scope = androidx.compose.runtime.rememberCoroutineScope()
         when (status.phase) {
             CarAppConnection.Phase.BINDING, CarAppConnection.Phase.HANDSHAKE ->
                 Text("Starting ${status.app ?: "the map"}…", style = MaterialTheme.typography.titleMedium)
             CarAppConnection.Phase.REJECTED, CarAppConnection.Phase.FAILED -> {
                 Text("${status.app ?: "The map app"} would not start.", style = MaterialTheme.typography.titleMedium)
                 status.detail?.let { Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant) }
-                TextButton(onClick = navigator::apps) { Text("Choose another app") }
+                GsButton(onClick = navigator::apps, tone = GsTone.Tonal) { Text("Choose another app") }
             }
-            else -> {
+            else -> if (!hasNavApps) {
+                // Nothing to auto-select and nothing to pick from Car apps either - this is the
+                // only case worth a distinct screen, since every other IDLE case resolves itself.
+                Text("No mapping apps found.", style = MaterialTheme.typography.titleMedium)
                 Text(
-                    if (hasLast) "Starting the map…" else "No map app chosen yet.",
-                    style = MaterialTheme.typography.titleMedium,
+                    "Install a navigation app that supports Android Auto and it will start here on its own.",
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
-                if (!hasLast) {
-                    Text(
-                        "Open Car apps and connect a navigation app; it will start here next time.",
-                        style = MaterialTheme.typography.bodyMedium,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    )
-                    TextButton(onClick = { navigator.apps() }) { Text("Car apps") }
-                }
+            } else if (hasLast) {
+                // IDLE with a last app on record means the driver stopped it themselves - it will
+                // not come back on its own, so the screen must offer a way to bring it back rather
+                // than sit on a "starting" message that never resolves.
+                Text("Map stopped.", style = MaterialTheme.typography.titleMedium)
+                GsButton(onClick = { scope.launch { CarServices.reconnectNav(frame) } }, tone = GsTone.Tonal) { Text("Reopen") }
+                GsButton(onClick = { navigator.apps() }, tone = GsTone.Tonal) { Text("Car apps") }
+            } else {
+                // Autostart is still picking one - a navigation app is installed, so this resolves
+                // to a "Starting..." state itself, in the next frame or two.
             }
         }
     }
 }
 
-/** Previous, play/pause, next and a seek bar, and nothing else: the full controls are in the media screen. */
+/**
+ * The player, docked beside the map: art, title, progress, transport, then like, shuffle, repeat
+ * and lyrics. While it's here the nav bar's pill steps aside on Home, so the controls never show
+ * twice. The X sends it back to the nav bar.
+ */
 @Composable
-private fun MiniPlayer(modifier: Modifier) {
+private fun DockedPlayer(now: NowPlaying, modifier: Modifier) {
+    val navigator = LocalCarNavigator.current
     val media = CarServices.media
-    val now by media.now.collectAsStateWithLifecycle()
     val context = LocalContext.current
+    val scheme = MaterialTheme.colorScheme
     val art by produceState(now.art, now.art, now.artUri) { value = now.art ?: MediaArt.load(context, now.artUri) }
 
-    var position by remember { mutableStateOf(0L) }
-    LaunchedEffect(now) {
-        while (true) {
-            position = now.currentPosition()
-            delay(500)
-        }
-    }
-
-    val navigator = LocalCarNavigator.current
-    Surface(
-        onClick = { navigator.media() },
-        modifier = modifier,
-        shape = RoundedCornerShape(EMBEDDED_RADIUS),
-        color = MaterialTheme.colorScheme.surfaceVariant,
-    ) {
-        Column(
-            Modifier.fillMaxSize().padding(18.dp),
-            horizontalAlignment = Alignment.CenterHorizontally,
-            verticalArrangement = Arrangement.Center,
-        ) {
-            Box(Modifier.size(128.dp).clip(RoundedCornerShape(EMBEDDED_RADIUS))) {
-                art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
-            }
-            Spacer(Modifier.height(10.dp))
-            Text(
-                now.title.ifEmpty { "Nothing playing" },
-                style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
-                maxLines = 1, overflow = TextOverflow.Ellipsis,
-            )
-            Text(
-                now.artist,
-                style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant,
-                maxLines = 1, overflow = TextOverflow.Ellipsis,
-            )
-
-            if (now.durationMs > 0) {
-                WavyProgress(
-                    fraction = position.toFloat() / now.durationMs,
-                    playing = now.state == PlaybackState.STATE_PLAYING,
-                    onSeek = { media.seek((it * now.durationMs).toLong()) },
-                    modifier = Modifier.padding(vertical = 4.dp),
-                )
-            } else {
-                Spacer(Modifier.height(16.dp))
-            }
-
-            Row(
-                horizontalArrangement = Arrangement.spacedBy(6.dp),
-                verticalAlignment = Alignment.CenterVertically,
-            ) {
-                IconButton(onClick = { media.previous() }, modifier = Modifier.size(48.dp)) {
-                    Icon(MediaIcons.Previous, "Previous", Modifier.size(30.dp))
-                }
-                FilledIconButton(onClick = media::togglePlay, modifier = Modifier.size(60.dp)) {
-                    Icon(
-                        if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow,
-                        if (now.playing) "Pause" else "Play",
-                        Modifier.size(36.dp),
+    Surface(modifier = modifier, color = rememberArtColor(art, MaterialTheme.colorScheme.surfaceVariant)) {
+        BoxWithConstraints(Modifier.fillMaxSize().padding(12.dp)) {
+            // Whatever height the controls below leave over, so the art grows on a taller
+            // screen and shrinks rather than pushing the buttons off a short one.
+            val artSize = minOf(maxWidth - 44.dp, maxHeight - 250.dp).coerceIn(56.dp, 200.dp)
+            Column(Modifier.fillMaxSize(), horizontalAlignment = Alignment.CenterHorizontally) {
+                Box(Modifier.fillMaxWidth()) {
+                    // Art opens the full media screen, same as on the pill.
+                    Box(
+                        Modifier
+                            .align(Alignment.TopCenter)
+                            .size(artSize)
+                            .clip(RoundedCornerShape(12.dp))
+                            .background(scheme.surface)
+                            .clickable { navigator.media() },
+                    ) {
+                        art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
+                    }
+                    GsIconButton(
+                        Icons.Filled.Close, "Back to the nav bar", navigator::closeSidePanel,
+                        Modifier.align(Alignment.TopEnd), size = 36.dp, iconSize = 20.dp,
                     )
                 }
-                IconButton(onClick = { media.next() }, modifier = Modifier.size(48.dp)) {
-                    Icon(MediaIcons.Next, "Next", Modifier.size(30.dp))
+                Spacer(Modifier.height(10.dp))
+                Text(
+                    now.title, style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold,
+                    maxLines = 1, overflow = TextOverflow.Ellipsis,
+                )
+                Text(
+                    now.artist, style = MaterialTheme.typography.bodyMedium, color = scheme.onSurfaceVariant,
+                    maxLines = 1, overflow = TextOverflow.Ellipsis,
+                )
+                if (now.durationMs > 0) {
+                    PlayerProgress(now, media, Modifier.fillMaxWidth().padding(vertical = 2.dp), showTimes = false)
+                } else {
+                    Spacer(Modifier.height(10.dp))
+                }
+                TransportRow(now, media, skip = 48.dp, modifier = Modifier.fillMaxWidth())
+                Spacer(Modifier.height(10.dp))
+                PlayModeRow(now, media, size = 42.dp, modifier = Modifier.fillMaxWidth()) {
+                    GsIconButton(
+                        ImageVector.vectorResource(R.drawable.lyrics_24), "Lyrics", navigator::showSideLyrics,
+                        size = 42.dp, iconSize = 22.dp,
+                    )
                 }
-            }
-
-            Spacer(Modifier.height(8.dp))
-            Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
-                val compact = PaddingValues(horizontal = 8.dp)
-                FilledTonalButton(
-                    onClick = { navigator.media(lyrics = true) },
-                    modifier = Modifier.weight(1f),
-                    contentPadding = compact,
-                ) { Text("Lyrics", maxLines = 1, softWrap = false) }
-                FilledTonalButton(
-                    onClick = navigator::minimisePlayer,
-                    modifier = Modifier.weight(1f),
-                    contentPadding = compact,
-                ) { Text("Minimise", maxLines = 1, softWrap = false) }
             }
         }
     }
 }
+
+/**
+ * Lyrics alone beside the map, big enough to read at a glance. No art: that space goes to a
+ * larger title and artist instead. The player goes back to the nav bar meanwhile, whose dock
+ * button swaps these back out for the controls.
+ */
+@Composable
+private fun SideLyrics(now: NowPlaying, modifier: Modifier) {
+    val navigator = LocalCarNavigator.current
+    val context = LocalContext.current
+    val art by produceState(now.art, now.art, now.artUri) { value = now.art ?: MediaArt.load(context, now.artUri) }
+    Surface(modifier = modifier, color = rememberArtColor(art, MaterialTheme.colorScheme.surfaceVariant)) {
+        Column(Modifier.fillMaxSize().padding(16.dp)) {
+            Row(verticalAlignment = Alignment.Top) {
+                Column(Modifier.weight(1f)) {
+                    Text(
+                        now.title, style = MaterialTheme.typography.headlineSmall, fontWeight = FontWeight.Bold,
+                        maxLines = 2, overflow = TextOverflow.Ellipsis,
+                    )
+                    Text(
+                        now.artist, style = MaterialTheme.typography.titleMedium,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        maxLines = 1, overflow = TextOverflow.Ellipsis,
+                    )
+                }
+                GsIconButton(Icons.Filled.Close, "Hide lyrics", navigator::closeSidePanel, size = 36.dp, iconSize = 20.dp)
+            }
+            Spacer(Modifier.height(12.dp))
+            LyricsPanel(now, Modifier.weight(1f).fillMaxWidth(), lineStyle = MaterialTheme.typography.headlineSmall)
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarKeyboard.kt

@@ -1,5 +1,6 @@
 package app.seb3thehacker.gearslip.car
 
+import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -8,12 +9,14 @@ import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ArrowBack
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -23,8 +26,23 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
-import androidx.compose.foundation.clickable
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.compositionLocalOf
+import androidx.compose.ui.platform.LocalConfiguration
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.coerceIn
+import androidx.compose.runtime.rememberUpdatedState
+import androidx.compose.runtime.LaunchedEffect
+
+/**
+ * Whether a [CarKeyboard] is on screen right now, so [CarUi] can give it the row of height the
+ * bottom nav bar normally holds instead of squeezing it in above - a driver typing has no use
+ * for Home/Apps/Settings shortcuts anyway, and the screen is small enough that the space matters.
+ */
+object CarKeyboardVisibility {
+    val state = mutableStateOf(false)
+}
 
 /**
  * A keyboard the host draws itself.
@@ -35,7 +53,13 @@ import androidx.compose.foundation.shape.RoundedCornerShape
  * the same reasons, so this does too - large keys, no long-press, no prediction.
  *
  * It is a pure function of [text]: every key reports the new string and holds no state beyond
- * which layer is showing.
+ * which layer is showing. Laid out like a PC's QWERTY keyboard rather than a phone's: shift and
+ * backspace flank the letter block (top-right and bottom-left of it, same as a physical board),
+ * not the space bar, so a fumbled reach for space never lands on delete instead.
+ *
+ * [onDismiss] is null wherever there's no keyboard-shown state independent of the screen itself
+ * (a search template, sign-in) - there, the header's own back action is the only way out and no
+ * dismiss button is drawn.
  */
 @Composable
 fun CarKeyboard(
@@ -45,48 +69,88 @@ fun CarKeyboard(
     modifier: Modifier = Modifier,
     submitIcon: Boolean = true,
     submitImage: ImageVector? = null,
+    onDismiss: (() -> Unit)? = null,
 ) {
     var symbols by remember { mutableStateOf(false) }
     var shifted by remember { mutableStateOf(false) }
 
-    val rows = if (symbols) SYMBOL_ROWS else LETTER_ROWS
+    DisposableEffect(Unit) {
+        CarKeyboardVisibility.state.value = true
+        onDispose { CarKeyboardVisibility.state.value = false }
+    }
 
-    Surface(
-        color = MaterialTheme.colorScheme.surfaceContainerHigh,
-        modifier = modifier.fillMaxWidth(),
-    ) {
-        Column(
-            Modifier.padding(horizontal = 6.dp, vertical = 4.dp),
-            verticalArrangement = Arrangement.spacedBy(4.dp),
+    // The same field on the phone, for typing on its own keyboard: see [PhoneTyping].
+    val latestChange by rememberUpdatedState(onTextChange)
+    val latestSubmit by rememberUpdatedState(onSubmit)
+    val latestDismiss by rememberUpdatedState(onDismiss)
+    val phoneField = remember {
+        PhoneTyping.open(text, { latestChange(it) }, { latestSubmit() }, onDismiss?.let { { latestDismiss?.invoke() } })
+    }
+    DisposableEffect(phoneField) { onDispose { PhoneTyping.close(phoneField) } }
+    LaunchedEffect(text) { PhoneTyping.carText(phoneField, text) }
+
+    val rows = if (symbols) SYMBOL_ROWS else LETTER_ROWS
+    val keyHeight = keyHeight(LocalConfiguration.current.screenHeightDp)
+
+    CompositionLocalProvider(LocalKeyHeight provides keyHeight) {
+        Surface(
+            color = MaterialTheme.colorScheme.surfaceContainerHigh,
+            modifier = modifier.fillMaxWidth(),
         ) {
-            rows.forEach { row ->
+            Column(
+                Modifier.padding(horizontal = 6.dp, vertical = 4.dp),
+                verticalArrangement = Arrangement.spacedBy(4.dp),
+            ) {
+                rows.dropLast(1).forEach { row ->
+                    Row(
+                        Modifier.fillMaxWidth(),
+                        horizontalArrangement = Arrangement.spacedBy(4.dp),
+                    ) {
+                        row.forEach { key ->
+                            val label = if (shifted && !symbols) key.uppercase() else key
+                            Key(label, Modifier.weight(1f)) {
+                                onTextChange(text + label)
+                                shifted = false
+                            }
+                        }
+                    }
+                }
+
+                // The bottom letter row: shift and backspace bookend it, exactly where a physical
+                // keyboard puts them relative to the letter block, not down beside the space bar.
                 Row(
                     Modifier.fillMaxWidth(),
                     horizontalArrangement = Arrangement.spacedBy(4.dp),
                 ) {
-                    row.forEach { key ->
+                    if (!symbols) {
+                        Key(if (shifted) "SHIFT" else "shift", Modifier.weight(1.6f)) { shifted = !shifted }
+                    }
+                    rows.last().forEach { key ->
                         val label = if (shifted && !symbols) key.uppercase() else key
                         Key(label, Modifier.weight(1f)) {
                             onTextChange(text + label)
                             shifted = false
                         }
                     }
+                    Key("⌫", Modifier.weight(1.6f)) {
+                        if (text.isNotEmpty()) onTextChange(text.dropLast(1))
+                    }
                 }
-            }
 
-            Row(
-                Modifier.fillMaxWidth(),
-                horizontalArrangement = Arrangement.spacedBy(4.dp),
-            ) {
-                Key(if (symbols) "abc" else "?123", Modifier.weight(1.4f)) { symbols = !symbols }
-                if (!symbols) {
-                    Key(if (shifted) "SHIFT" else "shift", Modifier.weight(1.4f)) { shifted = !shifted }
+                // Control row: no backspace here - it stays with the letters above, not next to the
+                // key most likely to be hit right after it by mistake. Search/enter takes the
+                // bottom-right corner, where a thumb expects it; dismiss (when offered) sits left of it.
+                Row(
+                    Modifier.fillMaxWidth(),
+                    horizontalArrangement = Arrangement.spacedBy(4.dp),
+                ) {
+                    Key(if (symbols) "abc" else "?123", Modifier.weight(1.4f)) { symbols = !symbols }
+                    Key("space", Modifier.weight(if (onDismiss != null) 3.2f else 4f)) { onTextChange("$text ") }
+                    if (onDismiss != null) {
+                        DismissKey(onDismiss, Modifier.weight(1.4f))
+                    }
+                    SubmitKey(Modifier.weight(1.6f), submitIcon, submitImage, onSubmit)
                 }
-                Key("space", Modifier.weight(3f)) { onTextChange("$text ") }
-                Key("⌫", Modifier.weight(1.4f)) {
-                    if (text.isNotEmpty()) onTextChange(text.dropLast(1))
-                }
-                SubmitKey(Modifier.weight(1.6f), submitIcon, submitImage, onSubmit)
             }
         }
     }
@@ -94,11 +158,11 @@ fun CarKeyboard(
 
 @Composable
 private fun Key(label: String, modifier: Modifier = Modifier, onClick: () -> Unit) {
-    Surface(
-        color = MaterialTheme.colorScheme.surfaceContainerHighest,
-        contentColor = MaterialTheme.colorScheme.onSurface,
+    GsIconBox(
+        onClick = onClick,
+        modifier = modifier.height(LocalKeyHeight.current),
+        colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHighest, MaterialTheme.colorScheme.onSurface),
         shape = RoundedCornerShape(8.dp),
-        modifier = modifier.height(KEY_HEIGHT).clickable(onClick = onClick),
     ) {
         Row(
             Modifier.fillMaxWidth(),
@@ -116,12 +180,30 @@ private fun Key(label: String, modifier: Modifier = Modifier, onClick: () -> Uni
 }
 
 @Composable
+private fun DismissKey(onClick: () -> Unit, modifier: Modifier = Modifier) {
+    GsIconBox(
+        onClick = onClick,
+        modifier = modifier.height(LocalKeyHeight.current),
+        colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHighest, MaterialTheme.colorScheme.onSurfaceVariant),
+        shape = RoundedCornerShape(8.dp),
+    ) {
+        Row(
+            Modifier.fillMaxWidth(),
+            horizontalArrangement = Arrangement.Center,
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Icon(Icons.Filled.Close, contentDescription = "Hide keyboard")
+        }
+    }
+}
+
+@Composable
 private fun SubmitKey(modifier: Modifier, search: Boolean, image: ImageVector?, onClick: () -> Unit) {
-    Surface(
-        color = MaterialTheme.colorScheme.primary,
-        contentColor = MaterialTheme.colorScheme.onPrimary,
+    GsIconBox(
+        onClick = onClick,
+        modifier = modifier.height(LocalKeyHeight.current),
+        colors = GsColors(MaterialTheme.colorScheme.primary, MaterialTheme.colorScheme.onPrimary),
         shape = RoundedCornerShape(8.dp),
-        modifier = modifier.height(KEY_HEIGHT).clickable(onClick = onClick),
     ) {
         Row(
             Modifier.fillMaxWidth(),
@@ -137,10 +219,12 @@ private fun SubmitKey(modifier: Modifier, search: Boolean, image: ImageVector?,
 }
 
 /**
- * Big enough to hit on a bumpy road, small enough that four rows plus a field plus a few
- * results all fit a 480px-tall screen - which is the real constraint here, not the key size.
+ * Big enough to hit on a bumpy road, small enough that four rows plus a field plus a few results
+ * still fit. A 480-tall screen sets the floor; a taller one (LIVI's 1280x720) gets bigger keys.
  */
-private val KEY_HEIGHT = 34.dp
+private fun keyHeight(screenHeightDp: Int): Dp = (screenHeightDp * 0.09f).dp.coerceIn(44.dp, 64.dp)
+
+private val LocalKeyHeight = compositionLocalOf { 44.dp }
 
 private val LETTER_ROWS = listOf(
     "qwertyuiop".map { it.toString() },

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarKeys.kt

@@ -0,0 +1,139 @@
+package app.seb3thehacker.gearslip.car
+
+import android.content.Context
+import android.os.Handler
+import android.os.Looper
+import android.view.KeyEvent
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.call.CallUiState
+import app.seb3thehacker.gearslip.call.CarCalls
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.SharedFlow
+
+/**
+ * The car's own buttons: steering wheel, rotary knob, D-pad and the hard keys around the screen.
+ *
+ * The head unit sends Android keycodes as they are, so the numbers here are android.view.KeyEvent's.
+ * Media, voice and call keys act straight away. Keys that move around the car UI (back, home, the
+ * knob) need a [CarNavigator], which only [CarUi] has, so they go out on [screenKeys]. Focus keys
+ * (D-pad, knob turns, OK) become real key events on the car's display through [focusSink], where
+ * Compose moves focus between buttons the same way it would with a keyboard.
+ */
+object CarKeys {
+
+    /** A key that changes which screen is showing. */
+    enum class ScreenKey { BACK, HOME, MAP, MEDIA, PHONE }
+
+    private val _screenKeys = MutableSharedFlow<ScreenKey>(extraBufferCapacity = 8)
+    val screenKeys: SharedFlow<ScreenKey> = _screenKeys
+
+    private val _focusMoves = MutableSharedFlow<Unit>(extraBufferCapacity = 1)
+
+    /** A knob turn or D-pad press, so controls that hide when left alone can come back. */
+    val focusMoves: SharedFlow<Unit> = _focusMoves
+
+    /** Delivers an Android key event to the car display; set while the car UI is showing. */
+    @Volatile var focusSink: ((keyCode: Int, down: Boolean) -> Unit)? = null
+
+    private var appContext: Context? = null
+    private val main = Handler(Looper.getMainLooper())
+
+    fun init(context: Context) { appContext = context.applicationContext }
+
+    /**
+     * Every key worth asking the head unit for. The binding request lists what the head unit
+     * offered; when it offers nothing (some units leave the list empty and send keys anyway),
+     * this is what's asked for instead.
+     */
+    val WANTED = listOf(
+        KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE, KeyEvent.KEYCODE_MEDIA_PLAY, KeyEvent.KEYCODE_MEDIA_PAUSE,
+        KeyEvent.KEYCODE_MEDIA_NEXT, KeyEvent.KEYCODE_MEDIA_PREVIOUS, KeyEvent.KEYCODE_MEDIA_STOP,
+        KeyEvent.KEYCODE_SEARCH, KeyEvent.KEYCODE_VOICE_ASSIST,
+        KeyEvent.KEYCODE_CALL, KeyEvent.KEYCODE_ENDCALL,
+        KeyEvent.KEYCODE_BACK, KeyEvent.KEYCODE_HOME,
+        KeyEvent.KEYCODE_DPAD_UP, KeyEvent.KEYCODE_DPAD_DOWN, KeyEvent.KEYCODE_DPAD_LEFT,
+        KeyEvent.KEYCODE_DPAD_RIGHT, KeyEvent.KEYCODE_DPAD_CENTER, KeyEvent.KEYCODE_ENTER,
+        KEYCODE_ROTARY_CONTROLLER, KEYCODE_MEDIA, KEYCODE_NAVIGATION, KEYCODE_TEL,
+    )
+
+    /**
+     * One key edge from the head unit. Most keys act on the press; focus keys pass both edges on,
+     * so a held D-pad key repeats the way it would anywhere else. Returns false for a key nothing
+     * here knows, for the caller to log.
+     */
+    fun onKey(keyCode: Int, down: Boolean, longPress: Boolean): Boolean {
+        if (keyCode in FOCUS_KEYS) {
+            _focusMoves.tryEmit(Unit)
+            focusSink?.invoke(keyCode, down)
+            return true
+        }
+        if (!down) return keyCode in WANTED
+        val media = CarServices.media
+        when (keyCode) {
+            KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE -> media.togglePlay()
+            KeyEvent.KEYCODE_MEDIA_PLAY -> if (!media.now.value.playing) media.togglePlay()
+            KeyEvent.KEYCODE_MEDIA_PAUSE, KeyEvent.KEYCODE_MEDIA_STOP -> if (media.now.value.playing) media.togglePlay()
+            KeyEvent.KEYCODE_MEDIA_NEXT -> media.next()
+            KeyEvent.KEYCODE_MEDIA_PREVIOUS -> media.previous()
+            KeyEvent.KEYCODE_SEARCH, KeyEvent.KEYCODE_VOICE_ASSIST -> voice()
+            KeyEvent.KEYCODE_CALL -> call()
+            KeyEvent.KEYCODE_ENDCALL -> endCall()
+            KeyEvent.KEYCODE_BACK -> screen(ScreenKey.BACK)
+            KeyEvent.KEYCODE_HOME -> screen(ScreenKey.HOME)
+            KEYCODE_NAVIGATION -> screen(ScreenKey.MAP)
+            KEYCODE_MEDIA -> screen(ScreenKey.MEDIA)
+            KEYCODE_TEL -> screen(ScreenKey.PHONE)
+            else -> return false
+        }
+        if (longPress) GearslipLog.i("keys: long press on $keyCode")
+        return true
+    }
+
+    /** A turn of the rotary knob: each click moves focus one step, like Tab or Shift+Tab. */
+    fun onRotate(delta: Int) {
+        val sink = focusSink ?: return
+        _focusMoves.tryEmit(Unit)
+        val code = if (delta > 0) KeyEvent.KEYCODE_TAB else KEYCODE_SHIFT_TAB
+        repeat(kotlin.math.abs(delta).coerceAtMost(MAX_ROTARY_STEPS)) {
+            sink(code, true)
+            sink(code, false)
+        }
+    }
+
+    /**
+     * The voice key: answers the message on screen if there is one, otherwise starts the
+     * assistant.
+     */
+    private fun voice() = main.post {
+        if (!VoiceReply.onVoiceKey()) CarAssistant.start()
+    }
+
+    /** Answers a ringing call; with nothing ringing, opens the phone screen. */
+    private fun call() = main.post {
+        val context = appContext ?: return@post
+        if (CarCalls.state.value is CallUiState.Ringing) CarCalls.answer(context) else screen(ScreenKey.PHONE)
+    }
+
+    private fun endCall() = main.post {
+        if (CarCalls.state.value is CallUiState.Ringing) CarCalls.decline()
+        else GearslipLog.i("keys: end call pressed with no ringing call; hanging up needs the dialer")
+    }
+
+    private fun screen(key: ScreenKey) { _screenKeys.tryEmit(key) }
+
+    // aap_protobuf's KeyCode.proto: car-only keys past the end of Android's own range.
+    const val KEYCODE_ROTARY_CONTROLLER = 65536
+    const val KEYCODE_MEDIA = 65537
+    const val KEYCODE_NAVIGATION = 65538
+    const val KEYCODE_TEL = 65540
+
+    /** Stands in for Shift+Tab: the sink sends Tab with the shift meta state. */
+    const val KEYCODE_SHIFT_TAB = -KeyEvent.KEYCODE_TAB
+
+    private const val MAX_ROTARY_STEPS = 5
+
+    private val FOCUS_KEYS = setOf(
+        KeyEvent.KEYCODE_DPAD_UP, KeyEvent.KEYCODE_DPAD_DOWN, KeyEvent.KEYCODE_DPAD_LEFT,
+        KeyEvent.KEYCODE_DPAD_RIGHT, KeyEvent.KEYCODE_DPAD_CENTER, KeyEvent.KEYCODE_ENTER,
+    )
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarLauncher.kt

@@ -1,6 +1,8 @@
 package app.seb3thehacker.gearslip.car
 
+import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.Image
+import androidx.compose.foundation.ExperimentalFoundationApi
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
@@ -13,17 +15,21 @@ import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.Search
-import androidx.compose.material.icons.filled.Settings
-import androidx.compose.material.icons.filled.Share
+import androidx.compose.material.icons.filled.Info
+import androidx.compose.material.icons.filled.KeyboardArrowDown
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.produceState
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.ImageBitmap
@@ -42,14 +48,20 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.border
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.lazy.grid.GridItemSpan
 import androidx.compose.material.icons.filled.Check
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.Warning
 import app.seb3thehacker.gearslip.host.KnownApps
 import app.seb3thehacker.gearslip.host.CarAppCatalog
 import app.seb3thehacker.gearslip.host.TemplateApp
 import app.seb3thehacker.gearslip.media.MediaApp
 import app.seb3thehacker.gearslip.media.MediaCatalog
+import app.seb3thehacker.gearslip.notify.MessagingApp
+import app.seb3thehacker.gearslip.notify.MessagingCatalog
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 
@@ -58,26 +70,46 @@ private class Tile(
     val label: String,
     val icon: ImageBitmap? = null,
     val glyph: ImageVector? = null,
-    /** Tested from start to finish with Gearslip; drawn with a check mark. */
-    val verified: Boolean = false,
+    /** Known not to work; drawn with a red X instead of being left off the launcher. */
+    val broken: Boolean = false,
+    val onLongClick: (() -> Unit)? = null,
     val onClick: () -> Unit,
 )
 
 /** A launcher app's data, kept apart from [Tile] so it can be cached without capturing click state. */
-private class Entry(
+internal class Entry(
     val label: String,
     val icon: ImageBitmap?,
     val template: TemplateApp? = null,
     val media: MediaApp? = null,
-)
+    val builtIn: BuiltInApp? = null,
+    val messaging: MessagingApp? = null,
+) {
+    /** What a pin or a nav-bar shortcut remembers this entry as; null for nothing pinnable. */
+    val componentId: String?
+        get() = builtIn?.let { BUILT_IN_PREFIX + it.id }
+            ?: messaging?.let { MESSAGING_PREFIX + it.packageName }
+            ?: (template?.component ?: media?.component)?.flattenToString()
+
+    val packageName: String?
+        get() = template?.component?.packageName ?: media?.component?.packageName ?: messaging?.packageName
+}
+
+/** A messaging app has no component of its own to open, so its pin carries the package instead. */
+internal const val MESSAGING_PREFIX = "messages:"
 
 /**
  * The installed car and media apps with their icons. Scanning the package manager and decoding
  * icons is slow, so [Prefetch] does it ahead of time and again at the start of each car session,
  * which is when new installs are picked up.
  */
-private object LauncherCache {
-    @Volatile var entries: List<Entry>? = null
+internal object LauncherCache {
+    /** Observed, not read once: the nav bar is drawn before the car session's rescan finishes,
+     * and an app installed since the last scan has to show up there when it does. */
+    private val flow = MutableStateFlow<List<Entry>?>(null)
+    val state: StateFlow<List<Entry>?> = flow.asStateFlow()
+
+    val entries: List<Entry>? get() = flow.value
 
     /** Returns the scan if there is one; [force] rescans. Synchronized so two callers share one scan. */
     @Synchronized
@@ -87,39 +119,148 @@ private object LauncherCache {
             context.packageManager.getApplicationIcon(pkg).toBitmap(128, 128).asImageBitmap()
         }.getOrNull()
 
-        val nav = CarAppCatalog.installed(context).map { Entry(it.label, iconOf(it.component.packageName), template = it) }
-        val media = MediaCatalog.installed(context).map { Entry(it.label, iconOf(it.component.packageName), media = it) }
-        return (nav + media).sortedBy { it.label.lowercase() }.also { entries = it }
+        val navApps = CarAppCatalog.installed(context)
+        val mediaApps = MediaCatalog.installed(context)
+        // Some apps (Spotify among them) ship both a Car App Library template and a legacy
+        // MediaBrowserService, which otherwise land as two identically-labeled tiles with no
+        // way to tell them apart. They're genuinely different screens - browsing versus Now
+        // Playing - so only the label needs disambiguating, not the tile itself.
+        val mediaPackages = mediaApps.map { it.component.packageName }.toSet()
+
+        val messagingApps = MessagingCatalog.installed(context)
+        // Google Messages ships its own car app, which won't start under Gearslip. Gearslip's
+        // own Messages screen does the same job, so a messenger gets only that tile.
+        val messagingPackages = messagingApps.map { it.packageName }.toSet()
+
+        val nav = navApps
+            .filter { it.component.packageName !in messagingPackages }
+            // An app whose template screen is rejected but whose player works through Gearslip
+            // (Spotify) shows only its player tile - a "· Browse" tile beside it would just report
+            // that the car screen isn't supported.
+            .filter { !(KnownApps.screenBroken(it.component.packageName) && KnownApps.playerWorks(it.component.packageName)) }
+            .map {
+                val label = if (it.component.packageName in mediaPackages) "${it.label} · Browse" else it.label
+                Entry(label, iconOf(it.component.packageName), template = it)
+            }
+        val media = mediaApps.map { Entry(it.label, iconOf(it.component.packageName), media = it) }
+        // A messenger that is also a car media app keeps only its player tile.
+        val messaging = messagingApps
+            .filter { it.packageName !in mediaPackages }
+            .map { Entry(it.label, iconOf(it.packageName), messaging = it) }
+        return (nav + media + messaging).sortedBy { it.label.lowercase() }.also { flow.value = it }
     }
 }
 
+/** Every app the launcher knows: Gearslip's own and the installed ones, rescans included. */
+@Composable
+internal fun rememberAllEntries(): List<Entry> {
+    val context = LocalContext.current
+    val installed by LauncherCache.state.collectAsState()
+    LaunchedEffect(context) {
+        if (LauncherCache.entries == null) withContext(Dispatchers.IO) { LauncherCache.load(context) }
+    }
+    return remember(installed) { BuiltInApps.entries + installed.orEmpty() }
+}
+
+/** The launcher's groups, in the order they're laid out. */
+private enum class AppGroup { PHONE, MAPS, MUSIC, MESSAGING, WEB, SCREEN_SHARING, OTHER, SETTINGS, EXIT }
+
+private fun groupOf(entry: Entry, mediaPackages: Set<String>): AppGroup {
+    entry.builtIn?.let {
+        return when (it) {
+            BuiltInApps.Phone -> AppGroup.PHONE
+            BuiltInApps.Web -> AppGroup.WEB
+            BuiltInApps.ScreenSharing -> AppGroup.SCREEN_SHARING
+            BuiltInApps.Exit -> AppGroup.EXIT
+            else -> AppGroup.SETTINGS
+        }
+    }
+    if (entry.media != null) return AppGroup.MUSIC
+    if (entry.messaging != null) return AppGroup.MESSAGING
+    val app = entry.template ?: return AppGroup.OTHER
+    // A media app's "· Browse" tile sits next to its player.
+    if (app.component.packageName in mediaPackages) return AppGroup.MUSIC
+    return when (app.kind) {
+        "calling" -> AppGroup.PHONE
+        "navigation", "poi", "parking", "charging" -> AppGroup.MAPS
+        // Template-only media apps may have no legacy browser/player tile to identify them.
+        "media" -> AppGroup.MUSIC
+        "messaging" -> AppGroup.MESSAGING
+        "settings" -> AppGroup.SETTINGS
+        else -> AppGroup.OTHER
+    }
+}
+
+/**
+ * The launcher's tiles in the order they're drawn: grouped by [AppGroup], alphabetical inside a
+ * group with Settings last of all, then with the driver's own moves from [custom] laid over it.
+ * Moved apps only trade places among themselves, so an app installed later still lands in its group.
+ */
+internal fun launcherOrder(all: List<Entry>, showVehicleData: Boolean, custom: List<String>): List<Entry> {
+    val shown = all.filter { it.builtIn !== BuiltInApps.VehicleData || showVehicleData }
+    val mediaPackages = shown.mapNotNull { it.media?.component?.packageName }.toSet()
+    val grouped = shown.sortedWith(
+        compareBy<Entry>({ groupOf(it, mediaPackages) }, { it.builtIn === BuiltInApps.Settings }, { it.label.lowercase() }),
+    )
+    if (custom.isEmpty()) return grouped
+    val rank = custom.withIndex().associate { (i, id) -> id to i }
+    fun Entry.rank() = componentId?.let { rank[it] }
+    val moved = grouped.filter { it.rank() != null }.sortedBy { it.rank() }.iterator()
+    return grouped.map { if (it.rank() != null) moved.next() else it }
+}
+
+/** An app by the id a pin or the running list knows it by, built-in or installed. */
+internal fun findEntry(id: String): Entry? =
+    BuiltInApps.entries.find { it.componentId == id } ?: LauncherCache.entries?.find { it.componentId == id }
+
 /** Rescans the car and media apps now, replacing the cached list; the launcher keeps showing the old one meanwhile. */
 fun warmLauncherApps(context: Context) { LauncherCache.load(context, force = true) }
 
-/** The app launcher: Web and Screen sharing, every car app the phone has, then Settings, as an icon grid. */
+/**
+ * Connects or opens [entry] - what tapping its tile does, shared with the nav bar's pinned
+ * shortcuts and its open-app icon so there is exactly one place that knows how to launch either
+ * kind of app.
+ */
+internal fun launchEntry(entry: Entry, navigator: CarNavigator, frame: CarEnvironment.Frame) {
+    entry.builtIn?.let { it.open(navigator); return }
+    entry.template?.let {
+        if (it.isNavigation) {
+            CarServices.connectNav(it, frame)
+            navigator.home()
+        } else {
+            CarServices.connectBrowse(it, frame)
+            navigator.browse(entry.label)
+        }
+    }
+    entry.media?.let { CarServices.openMedia(it); navigator.media() }
+    entry.messaging?.let { navigator.messages(it.packageName, it.label) }
+}
+
+/** The app launcher: every app as an icon grid, grouped Phone, Maps, Music, Messaging, Web, Screen sharing, Settings. */
 @Composable
 fun CarLauncher() {
-    val context = LocalContext.current
     val navigator = LocalCarNavigator.current
     val frame by CarEnvironment.frame.collectAsState()
 
     // Painted from the cache at once; scanned only if [Prefetch] has not got there first.
-    val installed by produceState(initialValue = LauncherCache.entries ?: emptyList(), context) {
-        value = LauncherCache.entries ?: withContext(Dispatchers.IO) { LauncherCache.load(context) }
+    val all = rememberAllEntries()
+    val running = rememberRunningApps()
+    val showVehicleData = rememberVehicleDataShown()
+
+    fun tileOf(entry: Entry): Tile {
+        // Only apps that don't work get a mark. The X rates an app's own car screens; a messenger
+        // shown on Gearslip's own Messages screen has none, so it never gets one.
+        val pkg = entry.packageName?.takeIf { entry.messaging == null }
+        val id = entry.componentId
+        return Tile(
+            entry.label, entry.icon, entry.builtIn?.glyph,
+            broken = pkg != null && (KnownApps.isBroken(pkg) || (entry.template != null && KnownApps.screenBroken(pkg))),
+            onLongClick = id?.let { { navigator.showAppMenu(it) } },
+        ) { openApp(entry, id?.let { running[it] }, navigator, frame) }
     }
 
-    val tiles = listOf(
-        Tile("Web", glyph = Icons.Filled.Search) { navigator.open("web") },
-        Tile("Screen sharing", glyph = Icons.Filled.Share) { navigator.open("phone") },
-    ) + installed.map { entry ->
-        val pkg = entry.template?.component?.packageName ?: entry.media?.component?.packageName
-        Tile(entry.label, entry.icon, verified = pkg != null && KnownApps.works(pkg)) {
-            entry.template?.let { CarServices.connectNav(it, frame); navigator.home() }
-            entry.media?.let { CarServices.openMedia(it); navigator.media() }
-        }
-    } + listOf(
-        Tile("Settings", glyph = Icons.Filled.Settings) { navigator.settings() },
-    )
+    val appOrder by CarSettings.appOrder.collectAsState()
+    val tiles = launcherOrder(all, showVehicleData, appOrder).map(::tileOf)
 
     LazyVerticalGrid(
         columns = GridCells.Adaptive(minSize = 108.dp),
@@ -129,49 +270,32 @@ fun CarLauncher() {
         verticalArrangement = Arrangement.spacedBy(12.dp),
     ) {
         items(tiles) { AppTile(it) }
-        if (tiles.any { it.verified }) {
-            item(span = { GridItemSpan(maxLineSpan) }) { VerifiedLegend() }
-        }
     }
 }
 
-/** Says what the check mark on a tile means, once, under the grid. */
+/** A red disc with a white X: marks a tile known not to work with Gearslip yet. */
 @Composable
-private fun VerifiedLegend() {
-    Row(
-        Modifier.fillMaxWidth().padding(top = 4.dp),
-        horizontalArrangement = Arrangement.Center,
-        verticalAlignment = Alignment.CenterVertically,
-    ) {
-        VerifiedBadge(16.dp)
-        Spacer(Modifier.width(8.dp))
-        Text(
-            "Tested and working with Gearslip",
-            style = MaterialTheme.typography.bodyMedium,
-            color = MaterialTheme.colorScheme.onSurfaceVariant,
-        )
-    }
-}
-
-/** A green disc with a white check: the same mark on every tile and in the legend. */
-@Composable
-private fun VerifiedBadge(size: androidx.compose.ui.unit.Dp, modifier: Modifier = Modifier) {
+private fun BrokenBadge(size: androidx.compose.ui.unit.Dp, modifier: Modifier = Modifier) {
     Box(
-        modifier.size(size).background(Color(0xFF43A047), CircleShape),
+        modifier.size(size).background(Color(0xFFD32F2F), CircleShape),
         contentAlignment = Alignment.Center,
     ) {
-        Icon(Icons.Filled.Check, contentDescription = "Tested and working", tint = Color.White, modifier = Modifier.size(size * 0.66f))
+        Icon(Icons.Filled.Close, contentDescription = "Doesn't work with Gearslip", tint = Color.White, modifier = Modifier.size(size * 0.66f))
     }
 }
 
+@OptIn(ExperimentalFoundationApi::class)
 @Composable
 private fun AppTile(tile: Tile) {
-    Surface(
+    val shape = MaterialTheme.shapes.extraLarge
+    // A long press opens the app's menu (pin, close) - the same gesture everywhere apps are
+    // shown, here and on the nav bar. GsIconBox marks it in the theme's style.
+    GsIconBox(
         onClick = tile.onClick,
+        onLongClick = tile.onLongClick,
         modifier = Modifier.height(120.dp),
-        shape = MaterialTheme.shapes.extraLarge,
-        color = MaterialTheme.colorScheme.surfaceVariant,
-        contentColor = MaterialTheme.colorScheme.onSurfaceVariant,
+        colors = GsColors(MaterialTheme.colorScheme.surfaceVariant, MaterialTheme.colorScheme.onSurfaceVariant),
+        shape = shape,
     ) {
         Box(Modifier.fillMaxSize()) {
             Column(
@@ -179,23 +303,42 @@ private fun AppTile(tile: Tile) {
                 horizontalAlignment = Alignment.CenterHorizontally,
                 verticalArrangement = Arrangement.Center,
             ) {
-                when {
-                    tile.icon != null -> Image(tile.icon, contentDescription = null, modifier = Modifier.size(52.dp))
-                    tile.glyph != null -> Icon(tile.glyph, contentDescription = null, modifier = Modifier.size(52.dp))
+                Box {
+                    TileIcon(tile)
+                    if (tile.broken) {
+                        // Pinned to the icon's lower corner, ringed in the tile's colour so it
+                        // reads as sitting on top of the icon.
+                        BrokenBadge(
+                            22.dp,
+                            Modifier.align(Alignment.BottomEnd).offset(x = 6.dp, y = 4.dp)
+                                .border(2.dp, MaterialTheme.colorScheme.surfaceVariant, CircleShape),
+                        )
+                    }
                 }
                 Spacer(Modifier.height(8.dp))
-                Text(
-                    tile.label,
-                    style = MaterialTheme.typography.labelLarge,
-                    fontWeight = FontWeight.SemiBold,
-                    textAlign = TextAlign.Center,
-                    maxLines = 2,
-                    overflow = TextOverflow.Ellipsis,
-                )
-            }
-            if (tile.verified) {
-                VerifiedBadge(24.dp, Modifier.align(Alignment.TopEnd).padding(8.dp))
+                TileLabel(tile)
             }
         }
     }
 }
+
+@Composable
+private fun TileIcon(tile: Tile) {
+    when {
+        tile.icon != null -> Image(tile.icon, contentDescription = null, modifier = Modifier.size(52.dp))
+        tile.glyph != null -> Icon(tile.glyph, contentDescription = null, modifier = Modifier.size(52.dp))
+    }
+}
+
+@Composable
+private fun TileLabel(tile: Tile, maxLines: Int = 2, modifier: Modifier = Modifier) {
+    Text(
+        tile.label,
+        modifier = modifier,
+        style = MaterialTheme.typography.labelLarge,
+        fontWeight = FontWeight.SemiBold,
+        textAlign = TextAlign.Center,
+        maxLines = maxLines,
+        overflow = TextOverflow.Ellipsis,
+    )
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarNavigator.kt

@@ -1,6 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.staticCompositionLocalOf
@@ -16,66 +17,136 @@ sealed interface CarScreen {
     /** Opened from the weather chip or the dashboard: now, the next hours and the week. */
     data object Weather : CarScreen
 
+    /** Everything the head unit's sensor channel has advertised and sent, raw. */
+    data object VehicleData : CarScreen
+
     /** The current media app, full size: browse, lyrics and controls. */
     data object Media : CarScreen
 
+    /**
+     * A templated app that isn't a navigation app - Spotify's own Car App Library service, among
+     * others - opened on its own screen rather than the Home map slot, which only a genuine
+     * navigation app can claim.
+     */
+    data object Browse : CarScreen
+
+    /** A messaging app's recent conversations, read from the notifications it posts. */
+    data class Messages(val packageName: String) : CarScreen
+
     /** [replyTo] is a notification key to open straight into its reply pane. */
     data class Notifications(val replyTo: String? = null) : CarScreen
     data class App(val id: String) : CarScreen
 }
 
+enum class SidePanel { NONE, CONTROLS, LYRICS }
+
+/** One step on the breadcrumb trail: the screen it shows and the word for it in the trail. */
+data class Crumb(val screen: CarScreen, val label: String)
+
 /**
- * Where the car UI is. A car touchscreen has no hardware back button, so [back] is driven by
- * the on-screen one; an open app can claim it first (a browser going back a page) through
- * [backInterceptor].
+ * Where the car UI is, and how it got there. A car touchscreen has no hardware back button, so
+ * every screen that isn't reached from [home] is pushed onto a trail (like a browser's history,
+ * or a file manager's breadcrumb bar) rather than replacing the last one outright - that's what
+ * lets the breadcrumb bar show "Home > Apps > Settings" and jump straight back to any of them,
+ * and lets [back] undo exactly one step instead of always dumping you back at Home. An open app
+ * can claim a back step first (a browser going back a page) through [backInterceptor].
  */
 class CarNavigator(startId: String) {
 
-    var current: CarScreen by mutableStateOf(
-        if (CarApps.find(startId) != null) CarScreen.App(startId) else CarScreen.Home,
+    private val stack = mutableStateListOf(
+        Crumb(
+            if (CarApps.find(startId) != null) CarScreen.App(startId) else CarScreen.Home,
+            "Home",
+        ),
     )
-        private set
+
+    /** The whole trail, root first. Size 1 means "at Home" - the breadcrumb bar hides then. */
+    val trail: List<Crumb> get() = stack
+
+    val current: CarScreen get() = stack.last().screen
 
     var backInterceptor: (() -> Boolean)? = null
 
-    fun home() { current = CarScreen.Home }
-
-    /**
-     * Minimised, the home screen's player folds into the nav bar and the map takes the width.
-     * Opening the media screen from the bar restores it, so leaving that screen lands on the
-     * home screen with the player back in place.
-     */
-    var playerMinimised by mutableStateOf(false)
-        private set
-
-    /** Set by the player's Lyrics button; the media screen reads it once when it opens. */
-    var lyricsRequested = false
-
-    fun minimisePlayer() { playerMinimised = true }
-
-    fun restorePlayer() { playerMinimised = false }
-
-    fun media(lyrics: Boolean = false) {
-        lyricsRequested = lyrics
-        playerMinimised = false
-        current = CarScreen.Media
+    /** Pushes a new step, unless it's the same screen already on top - tapping the button for
+     * where you already are shouldn't grow the trail. */
+    private fun push(screen: CarScreen, label: String) {
+        if (stack.last().screen == screen) return
+        stack.add(Crumb(screen, label))
     }
 
-    fun apps() { current = CarScreen.Apps }
+    /** The one way back to a clean slate: resets the whole trail to just Home. */
+    fun home() {
+        stack.clear()
+        stack.add(Crumb(CarScreen.Home, "Home"))
+    }
 
-    fun settings() { current = CarScreen.Settings }
+    /**
+     * What the column beside the map on Home is showing, if anything. The player lives in one
+     * place at a time: with [SidePanel.CONTROLS] it moves into the column and the nav bar's pill
+     * steps aside; with [SidePanel.LYRICS] the column is all lyrics and the pill comes back.
+     * Every other screen has no room for the column, so there the pill stays in the nav bar.
+     */
+    var sidePanel by mutableStateOf(SidePanel.NONE)
+        private set
 
-    fun dashboard() { current = CarScreen.Dashboard }
+    /**
+     * The pill's dock button: moves the player beside the map, going Home first if need be. With
+     * lyrics already there it swaps them for the controls; with the controls there it closes.
+     */
+    fun togglePlayerDock() {
+        if (current != CarScreen.Home) {
+            sidePanel = SidePanel.CONTROLS
+            home()
+            return
+        }
+        sidePanel = if (sidePanel == SidePanel.CONTROLS) SidePanel.NONE else SidePanel.CONTROLS
+    }
 
-    fun weather() { current = CarScreen.Weather }
+    fun showSideLyrics() { sidePanel = SidePanel.LYRICS }
 
-    fun notifications(replyTo: String? = null) { current = CarScreen.Notifications(replyTo) }
+    fun closeSidePanel() { sidePanel = SidePanel.NONE }
 
-    fun open(id: String) { current = CarScreen.App(id) }
+    /** Component id of the app whose long-press menu (pin, close) is open, or null. */
+    var appMenu by mutableStateOf<String?>(null)
+        private set
 
+    fun showAppMenu(componentId: String) { appMenu = componentId }
+
+    fun dismissAppMenu() { appMenu = null }
+
+    fun media() { push(CarScreen.Media, "Media") }
+
+    fun browse(label: String) { push(CarScreen.Browse, label) }
+
+    fun apps() { push(CarScreen.Apps, "Apps") }
+
+    fun settings() { push(CarScreen.Settings, "Settings") }
+
+    fun dashboard() { push(CarScreen.Dashboard, "Dashboard") }
+
+    fun weather() { push(CarScreen.Weather, "Weather") }
+
+    fun vehicleData() { push(CarScreen.VehicleData, "Vehicle data") }
+
+    fun messages(packageName: String, label: String) { push(CarScreen.Messages(packageName), label) }
+
+    /** The list lives on the dashboard; only a reply gets a screen of its own. */
+    fun notifications(replyTo: String? = null) {
+        if (replyTo == null) dashboard() else push(CarScreen.Notifications(replyTo), "Reply")
+    }
+
+    fun open(id: String) { push(CarScreen.App(id), CarApps.find(id)?.label ?: id) }
+
+    /** Jumps straight to a step already on the trail, dropping everything after it - what
+     * tapping a breadcrumb does. Index 0 (Home) is always on the trail, so this always succeeds. */
+    fun jumpTo(index: Int) {
+        while (stack.size > index + 1) stack.removeAt(stack.lastIndex)
+    }
+
+    /** One step back, same as tapping the crumb before the current one. */
     fun back() {
         if (backInterceptor?.invoke() == true) return
-        current = CarScreen.Home
+        if (stack.size > 1) stack.removeAt(stack.lastIndex)
     }
 }
 

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarSensors.kt

@@ -0,0 +1,95 @@
+package app.seb3thehacker.gearslip.car
+
+import app.seb3thehacker.gearslip.Protobuf
+import app.seb3thehacker.gearslip.Wire
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * Everything the head unit's sensor channel has offered and sent, for the "Vehicle data" screen.
+ *
+ * [ServiceDiscovery.findSensorService] tells us which numeric sensor types this head unit is
+ * willing to stream; [SensorType] names the ones publicly documented by other AA reverse-engineering
+ * projects (aasdk, openauto). That mapping is carried over from other projects, not verified
+ * against this exact unit, so it's a label, not a guarantee - the raw field dump next to it is
+ * the ground truth. Once [onEvent] starts decoding real traffic from the 2018 Uconnect, correct
+ * any type that turns out to be mislabeled.
+ */
+object CarSensors {
+
+    data class Reading(val typeId: Int, val typeName: String, val raw: String, val updatedAtMs: Long)
+
+    private val readingsFlow = MutableStateFlow<List<Reading>>(emptyList())
+    val readings: StateFlow<List<Reading>> = readingsFlow
+
+    /** Seeds one row per sensor type the head unit advertised, so the screen shows what's on
+     * offer even before the first event for it arrives. */
+    fun onDiscovered(types: List<Int>) {
+        readingsFlow.value = types.map { id ->
+            Reading(id, SensorType.name(id), "(waiting for data)", 0L)
+        }
+    }
+
+    /**
+     * One SensorEventIndication. Every reverse-engineered version of this message multiplexes
+     * every sensor type into one shared set of message-level field numbers (field N = "the data
+     * for sensor type N", roughly) rather than tagging events with the type id from
+     * SensorType.type - so field number is read here as a best-effort type id, same as the
+     * other services in this file.
+     */
+    fun onEvent(body: ByteArray) {
+        val now = System.currentTimeMillis()
+        val fields = Wire.fields(body)
+        val byType = fields.groupBy { it.number }
+        val updated = byType.mapValues { (number, group) ->
+            Reading(
+                number,
+                SensorType.name(number),
+                group.joinToString("; ") { field ->
+                    field.bytes?.let { Protobuf.describe(it, indent = "").trim().replace("\n", ", ") }
+                        ?: "varint=${field.varint}"
+                },
+                now,
+            )
+        }
+        val existing = readingsFlow.value.associateBy { it.typeId }
+        readingsFlow.value = (existing + updated).values.sortedBy { it.typeId }
+    }
+
+    fun clear() {
+        readingsFlow.value = emptyList()
+    }
+}
+
+/**
+ * Sensor type ids as named across public Android Auto reverse-engineering references. Treated as
+ * a label, not a fact - see [CarSensors] doc.
+ */
+object SensorType {
+    private val NAMES = mapOf(
+        1 to "Location (GPS)",
+        2 to "Compass",
+        3 to "Speed",
+        4 to "RPM",
+        5 to "Odometer",
+        6 to "Fuel",
+        7 to "Parking brake",
+        8 to "Gear",
+        9 to "Diagnostics",
+        10 to "Night mode",
+        11 to "Environment",
+        12 to "HVAC",
+        13 to "Driving status",
+        14 to "Dead reckoned location",
+        15 to "Passenger",
+        16 to "Door",
+        17 to "Light",
+        18 to "Tire pressure",
+        19 to "Accelerometer",
+        20 to "Gyroscope",
+        21 to "GPS satellites",
+        22 to "Toll card",
+    )
+
+    fun name(id: Int): String = NAMES[id]?.let { "$it (#$id)" } ?: "Sensor #$id"
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarServices.kt

@@ -2,13 +2,17 @@ package app.seb3thehacker.gearslip.car
 
 import android.content.ComponentName
 import android.content.Context
+import android.media.session.MediaSessionManager
+import android.media.session.PlaybackState
 import app.seb3thehacker.gearslip.audio.CarAudio
 import app.seb3thehacker.gearslip.host.CarAppCatalog
 import app.seb3thehacker.gearslip.host.CarAppConnection
+import app.seb3thehacker.gearslip.host.KnownApps
 import app.seb3thehacker.gearslip.host.TemplateApp
 import app.seb3thehacker.gearslip.media.CarMedia
 import app.seb3thehacker.gearslip.media.MediaApp
 import app.seb3thehacker.gearslip.media.MediaCatalog
+import app.seb3thehacker.gearslip.notify.GearslipNotificationListener
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -29,9 +33,29 @@ object CarServices {
     val nav: CarAppConnection by lazy { CarAppConnection(requireNotNull(context)) }
     val media: CarMedia by lazy { CarMedia(requireNotNull(context)) }
 
+    /** [nav], or null before the car screen has set things up. */
+    fun navOrNull(): CarAppConnection? = if (context != null) nav else null
+
+    /** [media], or null before the car screen has set things up: for code outside the car UI. */
+    fun mediaOrNull(): CarMedia? = if (context != null) media else null
+
+    /**
+     * A second, independent connection for templated apps that aren't navigation apps - Spotify's
+     * own Car App Library service is the first of these. Kept apart from [nav] so opening one
+     * can never bump the map off Home: this one gets its own screen ([CarScreen.Browse]) instead.
+     */
+    val browse: CarAppConnection by lazy { CarAppConnection(requireNotNull(context)) }
+
     private val _mediaApp = MutableStateFlow<MediaApp?>(null)
     val mediaApp: StateFlow<MediaApp?> = _mediaApp.asStateFlow()
 
+    /**
+     * Whether the phone has any navigation app installed at all. True until [autostart] has
+     * actually checked, so the home screen never flashes "none found" before it knows.
+     */
+    private val _hasNavApps = MutableStateFlow(true)
+    val hasNavApps: StateFlow<Boolean> = _hasNavApps.asStateFlow()
+
     /** Set when the driver stops the map by hand, so going Home doesn't immediately restart it. */
     private var navStopped = false
     private var autoplayPending = false
@@ -39,21 +63,65 @@ object CarServices {
     fun init(appContext: Context) {
         context = appContext.applicationContext
         app.seb3thehacker.gearslip.notify.CarMotion.start(appContext)
+        app.seb3thehacker.gearslip.call.CarCalls.start(appContext)
+        CarAssistant.init(appContext)
+        DirectionsVoice.init(appContext)
+        CarBluetooth.init(appContext)
+        BluetoothAudioCheck.init(appContext)
+        LocationCheck.init(appContext)
+        CarKeys.init(appContext)
+        VoiceReply.init(appContext)
+        // Loaded now, while nothing's waiting on it, so the first reply isn't slower than the rest.
+        app.seb3thehacker.gearslip.speech.SpeechEngine.warm(appContext)
     }
 
     // --- map -----------------------------------------------------------------------------
 
-    fun connectNav(app: TemplateApp, frame: CarEnvironment.Frame) {
+    /**
+     * [destination] is a search query to start navigating to right away - "navigate to X with Y"
+     * from the voice assistant - left null for a plain app launch. An app that's already the one
+     * running gets the destination sent to its live session instead of being torn down and
+     * rebuilt, same as [CarAppConnection.navigateTo] documents.
+     */
+    fun connectNav(app: TemplateApp, frame: CarEnvironment.Frame, destination: String? = null) {
         navStopped = false
         CarSettings.setLastNav(app.component.flattenToString())
-        nav.connect(app, frame.width, frame.height, frame.densityDpi)
+        if (destination != null && nav.connectedComponent == app.component) {
+            nav.navigateTo(destination)
+        } else {
+            // Another map app taking over ends the old one's route, or it keeps guiding unseen.
+            if (nav.connectedComponent != app.component) endRoute()
+            nav.connect(app, frame.width, frame.height, frame.densityDpi, destination)
+        }
     }
 
     fun stopNav() {
         navStopped = true
+        endRoute()
         nav.disconnect()
     }
 
+    private fun endRoute() {
+        if (nav.navigating) nav.stopNavigating()
+    }
+
+    /** Undoes [stopNav]'s hold so the last map app comes back, same as it would after a restart. */
+    suspend fun reconnectNav(frame: CarEnvironment.Frame) {
+        navStopped = false
+        autostart(frame)
+    }
+
+    // --- browse (non-navigation templated apps) -------------------------------------------
+
+    /** Opens a templated app that isn't navigation, on its own screen - never on Home. */
+    fun connectBrowse(app: TemplateApp, frame: CarEnvironment.Frame) {
+        browse.connect(app, frame.width, frame.height, frame.densityDpi)
+    }
+
+    fun stopBrowse() {
+        browse.disconnect()
+    }
+
     // --- media ---------------------------------------------------------------------------
 
     fun openMedia(app: MediaApp, autoplay: Boolean = false) {
@@ -70,6 +138,27 @@ object CarServices {
         if (CarSettings.pipeAudio.value) CarAudio.request()
     }
 
+    /**
+     * Reopens the media app used last, for the car's media button when nothing is open. False
+     * when there's none on record or it's been uninstalled since.
+     */
+    suspend fun reopenLastMedia(): Boolean {
+        val ctx = context ?: return false
+        val last = CarSettings.lastMedia.value?.let(ComponentName::unflattenFromString) ?: return false
+        val app = withContext(Dispatchers.IO) { MediaCatalog.installed(ctx) }
+            .firstOrNull { it.component == last } ?: return false
+        openMedia(app)
+        return true
+    }
+
+    /** Closes the media app from the car: stops what it's playing and drops the connection. */
+    fun closeMedia() {
+        if (media.now.value.playing) media.togglePlay()
+        media.disconnect()
+        _mediaApp.value = null
+        autoplayPending = false
+    }
+
     /** Called once the media app is connected: starts playback if that was asked for. */
     fun autoplayIfDue() {
         if (!autoplayPending) return
@@ -84,29 +173,93 @@ object CarServices {
         val ctx = context ?: return
 
         if (!navStopped && nav.status.value.phase == CarAppConnection.Phase.IDLE) {
+            val navApps = withContext(Dispatchers.IO) { CarAppCatalog.installed(ctx) }
+                .filter { it.isNavigation }
+            _hasNavApps.value = navApps.isNotEmpty()
+            // Never auto-pick one already known to fail outright - a driver who plugs in should
+            // land on a map, not on the one tile marked with a red X.
+            val candidates = navApps.filterNot { KnownApps.isBroken(it.component.packageName) }
             val last = CarSettings.lastNav.value
-            val app = last?.let { id ->
-                withContext(Dispatchers.IO) { CarAppCatalog.installed(ctx) }
-                    .firstOrNull { it.component == ComponentName.unflattenFromString(id) }
-            }
+            // The one used last, or - first run, nothing on record yet - whichever comes first:
+            // a driver who plugs in for the first time shouldn't have to go pick one by hand
+            // before the map shows up at all.
+            val lastComponent = last?.let(ComponentName::unflattenFromString)
+            val app = candidates.firstOrNull { it.component == lastComponent } ?: candidates.firstOrNull()
             if (app != null) connectNav(app, frame)
         }
 
         if (_mediaApp.value == null) {
-            val last = CarSettings.lastMedia.value
-            val app = last?.let { id ->
-                withContext(Dispatchers.IO) { MediaCatalog.installed(ctx) }
-                    .firstOrNull { it.component == ComponentName.unflattenFromString(id) }
+            val catalog = withContext(Dispatchers.IO) { MediaCatalog.installed(ctx) }
+            // Something already playing on the phone wins over whatever was last used in the car -
+            // a driver who started a song before plugging in shouldn't have to go open its tile by
+            // hand just to see what's already going.
+            val playing = withContext(Dispatchers.IO) { currentlyPlaying(ctx, catalog) }
+            if (playing != null) {
+                openMedia(playing)
+            } else {
+                val last = CarSettings.lastMedia.value
+                val app = last?.let { id -> catalog.firstOrNull { it.component == ComponentName.unflattenFromString(id) } }
+                if (app != null) openMedia(app, autoplay = CarSettings.autoplay.value)
             }
-            if (app != null) openMedia(app, autoplay = CarSettings.autoplay.value)
+        }
+    }
+
+    /**
+     * Whichever known car media app has an actively playing session right now, system-wide - not
+     * just the one Gearslip itself last connected to. Reading another app's session needs
+     * notification access, the same permission [app.seb3thehacker.gearslip.media.CarMedia]
+     * already asks for to control apps that won't share their library.
+     */
+    private fun currentlyPlaying(ctx: Context, catalog: List<MediaApp>): MediaApp? {
+        val manager = ctx.getSystemService(MediaSessionManager::class.java)
+        val listener = ComponentName(ctx, GearslipNotificationListener::class.java)
+        val sessions = try {
+            manager.getActiveSessions(listener)
+        } catch (e: SecurityException) {
+            return null
+        }
+        val playingPackages = sessions
+            .filter { it.playbackState?.state == PlaybackState.STATE_PLAYING }
+            .map { it.packageName }
+        return playingPackages.firstNotNullOfOrNull { pkg -> catalog.firstOrNull { it.component.packageName == pkg } }
+    }
+
+    /**
+     * The car went away mid-song: pause it, as Android Auto does, so it doesn't carry on out of
+     * the phone's speaker. Unplugging a USB accessory isn't "audio becoming noisy" the way
+     * headphones are, so the apps won't pause themselves. Every playing session is paused, not
+     * just the one Gearslip opened: anything the car was playing was going through the car.
+     */
+    fun pausePhoneMedia(why: String = "the car left") {
+        val ctx = context ?: return
+        val manager = ctx.getSystemService(MediaSessionManager::class.java)
+        val listener = ComponentName(ctx, GearslipNotificationListener::class.java)
+        val playing = try {
+            manager.getActiveSessions(listener).filter { it.playbackState?.state == PlaybackState.STATE_PLAYING }
+        } catch (e: SecurityException) {
+            null
+        }
+        if (playing == null) {
+            // No notification access: the app Gearslip itself is driving is all it can reach.
+            mediaOrNull()?.let { if (it.now.value.playing) it.togglePlay() }
+            return
+        }
+        playing.forEach { runCatching { it.transportControls.pause() } }
+        if (playing.isNotEmpty()) {
+            app.seb3thehacker.gearslip.GearslipLog.i("media: paused ${playing.joinToString { it.packageName }}: $why")
         }
     }
 
     /** The car went away: nothing should keep running for a screen that no longer exists. */
     fun shutdown() {
         context?.let { app.seb3thehacker.gearslip.notify.CarMotion.stop(it) }
+        app.seb3thehacker.gearslip.call.CarCalls.stop()
         runCatching { nav.disconnect() }
         runCatching { media.disconnect() }
+        runCatching { browse.disconnect() }
+        CarAssistant.cancel()
+        // About 900 MB that nothing needs once the car's gone.
+        app.seb3thehacker.gearslip.speech.SpeechEngine.unload()
         CarAudio.release()
         _mediaApp.value = null
         navStopped = false

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarSettings.kt

@@ -2,11 +2,19 @@ package app.seb3thehacker.gearslip.car
 
 import android.content.Context
 import app.seb3thehacker.gearslip.AppSettings
+import app.seb3thehacker.gearslip.audio.CarAudio
+import app.seb3thehacker.gearslip.car.theme.GsTheme
+import app.seb3thehacker.gearslip.car.theme.GsThemes
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 
 enum class NightMode { AUTO, DAY, NIGHT }
 
+/** Distances and temperatures. [AUTO] goes by the phone's region. */
+enum class Units { AUTO, IMPERIAL, METRIC }
+
+/** Where a new message shows: [NAV_BAR] turns the clock button into it, [CARD] floats a card top right. */
+
 /** The car UI's own colours. Separate from [NightMode], which is about the light outside (the map). */
 enum class AppTheme { PHONE, LIGHT, DARK }
 
@@ -20,10 +28,29 @@ object CarSettings {
     private const val KEY_OPEN = "car_open_on_connect"
     private const val KEY_NIGHT = "car_night_mode"
     private const val KEY_PIPE_AUDIO = "car_pipe_audio"
+private const val KEY_SPEAK_DIRECTIONS = "car_speak_directions"
+private const val KEY_BLUETOOTH_WARNING = "car_bluetooth_warning"
+private const val KEY_LOCATION_WARNING = "car_location_warning"
+    private const val KEY_AUDIO_CHOICE_ASKED = "car_audio_choice_asked"
     private const val KEY_LAST_NAV = "car_last_nav"
     private const val KEY_LAST_MEDIA = "car_last_media"
     private const val KEY_AUTOPLAY = "car_autoplay"
+    private const val KEY_PLAYER_TITLE = "car_player_title"
     private const val KEY_THEME = "car_app_theme"
+    private const val KEY_UI_THEME = "car_ui_theme"
+    private const val KEY_PINNED = "car_pinned_apps"
+    private const val KEY_APP_ORDER = "car_app_order"
+    private const val KEY_EXPERIMENTAL_FEATURES = "car_experimental_features"
+    private const val KEY_SYSTEM_SPEECH = "car_system_speech"
+    private const val KEY_CAR_SENSORS = "car_sensors_enabled"
+    private const val KEY_SEEN_SAFETY_WARNING = "car_seen_safety_warning"
+    private const val KEY_UNITS = "car_units"
+    private const val KEY_WHATS_NEW = "car_whats_new_after_updates"
+    private const val KEY_WHATS_NEW_SEEN = "car_whats_new_seen_code"
+
+    /** How many shortcuts the nav bar makes room for; a driver reaching for one needs it to
+     * still be on the bar, not off the edge of a long list. */
+    const val MAX_PINNED = 3
 
     /** Id of the app to open on connect; [HOME] opens the launcher. */
     const val HOME = "home"
@@ -34,11 +61,77 @@ object CarSettings {
     private val openFlow = MutableStateFlow(HOME)
     private val nightFlow = MutableStateFlow(NightMode.AUTO)
     private val pipeAudioFlow = MutableStateFlow(true)
+    private val speakDirectionsFlow = MutableStateFlow(true)
+    private val bluetoothWarningFlow = MutableStateFlow(true)
+    private val locationWarningFlow = MutableStateFlow(true)
     private val lastNavFlow = MutableStateFlow<String?>(null)
     private val lastMediaFlow = MutableStateFlow<String?>(null)
     private val autoplayFlow = MutableStateFlow(false)
+    private val playerTitleFlow = MutableStateFlow(false)
     private val themeFlow = MutableStateFlow(AppTheme.PHONE)
     val appTheme: StateFlow<AppTheme> = themeFlow
+    private val uiThemeFlow = MutableStateFlow(GsThemes.default.id)
+
+    /** Id of the [GsTheme] controls are drawn in; an unknown id falls back to the default. */
+    val uiTheme: StateFlow<String> = uiThemeFlow
+    private val pinnedFlow = MutableStateFlow<Set<String>>(emptySet())
+    private val appOrderFlow = MutableStateFlow<List<String>>(emptyList())
+    private val experimentalFeaturesFlow = MutableStateFlow(false)
+    private val systemSpeechFlow = MutableStateFlow(false)
+    private val carSensorsFlow = MutableStateFlow(false)
+    private val seenSafetyWarningFlow = MutableStateFlow(false)
+    private val unitsFlow = MutableStateFlow(Units.AUTO)
+
+    val units: StateFlow<Units> = unitsFlow
+
+
+    private val whatsNewFlow = MutableStateFlow(true)
+    private val whatsNewSeenFlow = MutableStateFlow(0)
+    private val whatsNewOpenFlow = MutableStateFlow(false)
+
+    /** Whether the car screen shows what's new once after each update. */
+    val whatsNewAfterUpdates: StateFlow<Boolean> = whatsNewFlow
+
+    /** Version code whose notes the car screen last showed. */
+    val whatsNewSeen: StateFlow<Int> = whatsNewSeenFlow
+
+    /** Opened by hand from Settings, whatever the two above say. Not saved. */
+    val whatsNewOpen: StateFlow<Boolean> = whatsNewOpenFlow
+
+    fun setWhatsNewAfterUpdates(on: Boolean) {
+        whatsNewFlow.value = on
+        AppSettings.putString(app, KEY_WHATS_NEW, on.toString())
+    }
+
+    fun openWhatsNew() { whatsNewOpenFlow.value = true }
+
+    /** Closes the notes and marks [versionCode]'s as read. */
+    fun closeWhatsNew(versionCode: Int) {
+        whatsNewOpenFlow.value = false
+        whatsNewSeenFlow.value = versionCode
+        AppSettings.putString(app, KEY_WHATS_NEW_SEEN, versionCode.toString())
+    }
+
+
+
+    /** Whether to show miles, feet and °F; [Units.AUTO] follows the countries that still use them. */
+    fun imperial(): Boolean = when (unitsFlow.value) {
+        Units.IMPERIAL -> true
+        Units.METRIC -> false
+        Units.AUTO -> java.util.Locale.getDefault().country in setOf("US", "LR", "MM")
+    }
+
+    fun setUnits(units: Units) {
+        unitsFlow.value = units
+        AppSettings.putString(app, KEY_UNITS, units.name)
+        Weather.refresh(app, force = true)
+    }
+
+    /** Flattened component names of the apps long-pressed onto the nav bar as shortcuts. */
+    val pinnedApps: StateFlow<Set<String>> = pinnedFlow
+
+    /** The launcher's order once the driver has moved a tile; empty keeps the grouped default. */
+    val appOrder: StateFlow<List<String>> = appOrderFlow
 
     /** Flattened component names of the map and media apps used last, brought back on connect. */
     val lastNav: StateFlow<String?> = lastNavFlow
@@ -47,6 +140,12 @@ object CarSettings {
     /** Whether the media app starts playing by itself when the car connects. */
     val autoplay: StateFlow<Boolean> = autoplayFlow
 
+    /**
+     * The nav bar's player keeps the song title up, with play/pause and the dock button, instead of
+     * settling to the skip buttons once a new song has announced itself.
+     */
+    val playerTitle: StateFlow<Boolean> = playerTitleFlow
+
     val scale: StateFlow<Float> = scaleFlow
     val openOnConnect: StateFlow<String> = openFlow
     val nightMode: StateFlow<NightMode> = nightFlow
@@ -55,10 +154,63 @@ object CarSettings {
      * Whether a media app's sound is captured and sent over the car link. On by default, since
      * sound in the car is the point of the exercise; the platform allows the capture only behind a
      * consent dialog, which [app.seb3thehacker.gearslip.audio.CarAudio] raises once the car has
-     * somewhere to play it. Turned off, the app plays through the phone's normal output instead.
+     * somewhere to play it. Turned off ("Bluetooth" in the settings), the app plays through the
+     * phone's normal output instead, and Android never asks.
      */
     val pipeAudio: StateFlow<Boolean> = pipeAudioFlow
 
+    /** Gearslip reads the map app's turns aloud on the car's directions channel; see DirectionsVoice. */
+    val speakDirections: StateFlow<Boolean> = speakDirectionsFlow
+
+    /** With Bluetooth audio, warn when the phone isn't connected to the car; see BluetoothAudioCheck. */
+    val bluetoothWarning: StateFlow<Boolean> = bluetoothWarningFlow
+
+    /** Warn on the car when the phone's location is off; see LocationCheck. */
+    val locationWarning: StateFlow<Boolean> = locationWarningFlow
+
+    /**
+     * Whether the driver has already been offered Bluetooth after turning down the capture
+     * dialog. Offered once only: someone who chose to keep the USB route shouldn't be nagged.
+     */
+    /** False until the driver picks USB or Bluetooth, in setup or in settings. */
+    val pipeAudioChosen: Boolean
+        get() = AppSettings.getString(app, KEY_PIPE_AUDIO, "") != ""
+
+    val audioChoiceAsked: Boolean
+        get() = AppSettings.getString(app, KEY_AUDIO_CHOICE_ASKED, "false") == "true"
+
+    fun markAudioChoiceAsked() = AppSettings.putString(app, KEY_AUDIO_CHOICE_ASKED, "true")
+
+    /**
+     * Off by default: a driver has to opt into experimental features as a whole before any of
+     * them - the voice assistant included - show up to turn on individually.
+     */
+    val experimentalFeaturesEnabled: StateFlow<Boolean> = experimentalFeaturesFlow
+
+    /** Listen with the phone's own speech service instead of Gearslip's on-device model. */
+    val systemSpeech: StateFlow<Boolean> = systemSpeechFlow
+
+    /**
+     * Vehicle data is experimental and off by default: the launcher's tile for it, and the
+     * voice assistant's "vehicle data" command, only show up once this and
+     * [experimentalFeaturesEnabled] are both on. See [app.seb3thehacker.gearslip.car.CarSensors]
+     * for why the raw sensor feed it shows is worth gating - the field labels are unverified.
+     */
+    val carSensorsEnabled: StateFlow<Boolean> = carSensorsFlow
+
+    /**
+     * Whether the car screen's own "drive safely" warning has already been shown and dismissed
+     * once, from this same install. Separate from the phone side's own compat/safety dialogs -
+     * a driver who only ever plugs in and never opens the phone app should still see this once,
+     * on the screen they are actually about to use while driving.
+     */
+    val hasSeenSafetyWarning: StateFlow<Boolean> = seenSafetyWarningFlow
+
+    fun markSafetyWarningSeen() {
+        seenSafetyWarningFlow.value = true
+        AppSettings.putString(app, KEY_SEEN_SAFETY_WARNING, "true")
+    }
+
     fun init(context: Context) {
         app = context.applicationContext
         scaleFlow.value = AppSettings.getString(app, KEY_SCALE, "1.0").toFloatOrNull() ?: 1f
@@ -68,11 +220,31 @@ object CarSettings {
         themeFlow.value = runCatching {
             AppTheme.valueOf(AppSettings.getString(app, KEY_THEME, AppTheme.PHONE.name))
         }.getOrDefault(AppTheme.PHONE)
+        uiThemeFlow.value = AppSettings.getString(app, KEY_UI_THEME, GsThemes.default.id)
         autoplayFlow.value = AppSettings.getString(app, KEY_AUTOPLAY, "false") == "true"
+        playerTitleFlow.value = AppSettings.getString(app, KEY_PLAYER_TITLE, "false") == "true"
         pipeAudioFlow.value = AppSettings.getString(app, KEY_PIPE_AUDIO, "true") == "true"
+        // Until the driver sets it, on for USB audio and off for Bluetooth, where the map app's
+        // own voice already reaches the car.
+        speakDirectionsFlow.value = AppSettings.getString(app, KEY_SPEAK_DIRECTIONS, pipeAudioFlow.value.toString()) == "true"
+        bluetoothWarningFlow.value = AppSettings.getString(app, KEY_BLUETOOTH_WARNING, "true") == "true"
+        locationWarningFlow.value = AppSettings.getString(app, KEY_LOCATION_WARNING, "true") == "true"
         nightFlow.value = runCatching {
             NightMode.valueOf(AppSettings.getString(app, KEY_NIGHT, NightMode.AUTO.name))
         }.getOrDefault(NightMode.AUTO)
+        pinnedFlow.value = AppSettings.getString(app, KEY_PINNED, "")
+            .split(",").filter { it.isNotEmpty() }.toSet()
+        appOrderFlow.value = AppSettings.getString(app, KEY_APP_ORDER, "")
+            .split(",").filter { it.isNotEmpty() }
+        experimentalFeaturesFlow.value = AppSettings.getString(app, KEY_EXPERIMENTAL_FEATURES, "false") == "true"
+        systemSpeechFlow.value = AppSettings.getString(app, KEY_SYSTEM_SPEECH, "false") == "true"
+        carSensorsFlow.value = AppSettings.getString(app, KEY_CAR_SENSORS, "false") == "true"
+        seenSafetyWarningFlow.value = AppSettings.getString(app, KEY_SEEN_SAFETY_WARNING, "false") == "true"
+        unitsFlow.value = runCatching {
+            Units.valueOf(AppSettings.getString(app, KEY_UNITS, Units.AUTO.name))
+        }.getOrDefault(Units.AUTO)
+        whatsNewFlow.value = AppSettings.getString(app, KEY_WHATS_NEW, "true") == "true"
+        whatsNewSeenFlow.value = AppSettings.getString(app, KEY_WHATS_NEW_SEEN, "0").toIntOrNull() ?: 0
     }
 
     fun setScale(value: Float) {
@@ -100,14 +272,62 @@ object CarSettings {
         AppSettings.putString(app, KEY_THEME, theme.name)
     }
 
+    fun setUiTheme(id: String) {
+        uiThemeFlow.value = id
+        AppSettings.putString(app, KEY_UI_THEME, id)
+    }
+
+    fun setPlayerTitle(on: Boolean) {
+        playerTitleFlow.value = on
+        AppSettings.putString(app, KEY_PLAYER_TITLE, on.toString())
+    }
+
     fun setAutoplay(on: Boolean) {
         autoplayFlow.value = on
         AppSettings.putString(app, KEY_AUTOPLAY, on.toString())
     }
 
+    /**
+     * Takes effect at once: switching to Bluetooth mid-drive stops the capture, and switching
+     * back asks for it again (or waits for the car, if none is connected).
+     */
     fun setPipeAudio(on: Boolean) {
-        pipeAudioFlow.value = on
+        // Saved even when unchanged, so picking the default still counts as a choice.
         AppSettings.putString(app, KEY_PIPE_AUDIO, on.toString())
+        if (pipeAudioFlow.value == on) return
+        pipeAudioFlow.value = on
+        if (AppSettings.getString(app, KEY_SPEAK_DIRECTIONS, "") == "") speakDirectionsFlow.value = on
+        if (on) CarAudio.request() else CarAudio.release()
+    }
+
+    fun setSpeakDirections(on: Boolean) {
+        speakDirectionsFlow.value = on
+        AppSettings.putString(app, KEY_SPEAK_DIRECTIONS, on.toString())
+    }
+
+    fun setBluetoothWarning(on: Boolean) {
+        bluetoothWarningFlow.value = on
+        AppSettings.putString(app, KEY_BLUETOOTH_WARNING, on.toString())
+    }
+
+    fun setLocationWarning(on: Boolean) {
+        locationWarningFlow.value = on
+        AppSettings.putString(app, KEY_LOCATION_WARNING, on.toString())
+    }
+
+    fun setExperimentalFeaturesEnabled(on: Boolean) {
+        experimentalFeaturesFlow.value = on
+        AppSettings.putString(app, KEY_EXPERIMENTAL_FEATURES, on.toString())
+    }
+
+    fun setSystemSpeech(on: Boolean) {
+        systemSpeechFlow.value = on
+        AppSettings.putString(app, KEY_SYSTEM_SPEECH, on.toString())
+    }
+
+    fun setCarSensorsEnabled(on: Boolean) {
+        carSensorsFlow.value = on
+        AppSettings.putString(app, KEY_CAR_SENSORS, on.toString())
     }
 
     fun setNightMode(mode: NightMode) {
@@ -115,4 +335,22 @@ object CarSettings {
         AppSettings.putString(app, KEY_NIGHT, mode.name)
         CarEnvironment.refresh()
     }
+
+    /** Long-pressed onto or off the nav bar. Silently does nothing past [MAX_PINNED] rather than
+     * bumping the oldest pin - a driver who filled the bar on purpose shouldn't lose one by accident. */
+    fun togglePin(component: String) {
+        val current = pinnedFlow.value
+        val next = when {
+            component in current -> current - component
+            current.size >= MAX_PINNED -> return
+            else -> current + component
+        }
+        pinnedFlow.value = next
+        AppSettings.putString(app, KEY_PINNED, next.joinToString(","))
+    }
+
+    fun setAppOrder(ids: List<String>) {
+        appOrderFlow.value = ids
+        AppSettings.putString(app, KEY_APP_ORDER, ids.joinToString(","))
+    }
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarSettingsScreen.kt

@@ -1,5 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
+
+import app.seb3thehacker.gearslip.car.theme.*
 import android.os.Build
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
@@ -9,11 +11,13 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.Button
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
+import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.collectAsState
@@ -28,6 +32,9 @@ import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.car.theme.GsColors
+import app.seb3thehacker.gearslip.car.theme.GsIconBox
+import app.seb3thehacker.gearslip.car.theme.GsThemes
 import app.seb3thehacker.gearslip.AppSettings
 import app.seb3thehacker.gearslip.ui.CertSummary
 import kotlinx.coroutines.Dispatchers
@@ -43,9 +50,19 @@ fun CarSettingsScreen() {
     val scale by CarSettings.scale.collectAsState()
     val open by CarSettings.openOnConnect.collectAsState()
     val night by CarSettings.nightMode.collectAsState()
+    val units by CarSettings.units.collectAsState()
+    val whatsNew by CarSettings.whatsNewAfterUpdates.collectAsState()
     val pipeAudio by CarSettings.pipeAudio.collectAsState()
+    val speakDirections by CarSettings.speakDirections.collectAsState()
+    val bluetoothWarning by CarSettings.bluetoothWarning.collectAsState()
+    val locationWarning by CarSettings.locationWarning.collectAsState()
     val autoplay by CarSettings.autoplay.collectAsState()
+    val playerTitle by CarSettings.playerTitle.collectAsState()
     val theme by CarSettings.appTheme.collectAsState()
+    val uiTheme by CarSettings.uiTheme.collectAsState()
+    val experimentalFeatures by CarSettings.experimentalFeaturesEnabled.collectAsState()
+    val carSensors by CarSettings.carSensorsEnabled.collectAsState()
+    val systemSpeech by CarSettings.systemSpeech.collectAsState()
     val display by CarEnvironment.display.collectAsState()
     val vehicle by CarEnvironment.vehicle.collectAsState()
     val context = LocalContext.current
@@ -60,7 +77,7 @@ fun CarSettingsScreen() {
             .padding(horizontal = 24.dp, vertical = 16.dp),
         verticalArrangement = Arrangement.spacedBy(20.dp),
     ) {
-        Text("Settings", style = MaterialTheme.typography.headlineMedium, fontWeight = FontWeight.Bold)
+        ScreenHeader("Settings")
 
         ChoiceRow(
             "Open on connect",
@@ -80,12 +97,30 @@ fun CarSettingsScreen() {
             theme,
         ) { CarSettings.setAppTheme(it) }
 
+        ChoiceRow(
+            "Theme",
+            GsThemes.builtIn.map { it.id to it.name },
+            uiTheme,
+        ) { CarSettings.setUiTheme(it) }
+
         ChoiceRow(
             "Map day/night",
             listOf(NightMode.AUTO to "Auto", NightMode.DAY to "Day", NightMode.NIGHT to "Night"),
             night,
         ) { CarSettings.setNightMode(it) }
 
+        ChoiceRow(
+            "Units",
+            listOf(Units.AUTO to "Auto", Units.IMPERIAL to "Imperial (mi, ft, °F)", Units.METRIC to "Metric (km, m, °C)"),
+            units,
+        ) { CarSettings.setUnits(it) }
+
+        ChoiceRow(
+            "Player in the nav bar",
+            listOf(false to "Skip buttons", true to "Song title"),
+            playerTitle,
+        ) { CarSettings.setPlayerTitle(it) }
+
         ChoiceRow(
             "Autoplay on connect",
             listOf(false to "Off", true to "On"),
@@ -93,23 +128,63 @@ fun CarSettingsScreen() {
         ) { CarSettings.setAutoplay(it) }
 
         ChoiceRow(
-            "Media audio",
-            listOf(false to "Phone output", true to "Through Gearslip"),
+            "Car audio",
+            listOf(false to "Bluetooth", true to "USB"),
             pipeAudio,
         ) { CarSettings.setPipeAudio(it) }
         Text(
-            "Through Gearslip sends the sound over the USB link. Android asks for consent the " +
-                "first time a media app plays in the car, and some apps refuse to be captured at " +
-                "all. Phone output needs no permission: the app plays as it normally would, for " +
-                "example over Bluetooth to the car.",
+            "USB sends the phone's sound through Gearslip. Android asks to share your screen each " +
+                "drive, and a few apps block it. Bluetooth plays as the phone normally would, and " +
+                "Android never asks.",
+            style = MaterialTheme.typography.bodySmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+        if (!pipeAudio) {
+            ChoiceRow(
+                "Warn when Bluetooth isn't connected",
+                listOf(false to "Off", true to "On"),
+                bluetoothWarning,
+            ) { CarSettings.setBluetoothWarning(it) }
+        }
+        ChoiceRow(
+            "Warn when location is off",
+            listOf(false to "Off", true to "On"),
+            locationWarning,
+        ) { CarSettings.setLocationWarning(it) }
+
+        ChoiceRow(
+            "Spoken directions",
+            listOf(false to "Off", true to "On"),
+            speakDirections,
+        ) { CarSettings.setSpeakDirections(it) }
+        Text(
+            "Gearslip reads each turn aloud through the car's speakers, and the music dips while it " +
+                "speaks. Turn it off if your map app's own voice already plays in the car.",
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
 
+        ExperimentalFeatureRow(
+            title = "Use the phone's speech recognition",
+            description = "Listens through the phone's own speech service instead of Gearslip's. On " +
+                "most phones that's Google's, which may send your voice to Google. GrapheneOS has " +
+                "none, so Gearslip keeps using its own.",
+            checked = systemSpeech,
+        ) { CarSettings.setSystemSpeech(it) }
+
         WebPageSetting()
 
         ScreenFit(vehicle)
 
+        ChoiceRow(
+            "Experimental features",
+            listOf(false to "Hide", true to "Show"),
+            experimentalFeatures,
+        ) { CarSettings.setExperimentalFeaturesEnabled(it) }
+        if (experimentalFeatures) {
+            ExperimentalFeaturesList(carSensors)
+        }
+
         Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
             Text("Connection", style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
             Info("Phone", "${Build.MANUFACTURER} ${Build.MODEL}")
@@ -117,9 +192,20 @@ fun CarSettingsScreen() {
             Info("Video", display.ifEmpty { "-" })
             Info("Certificate", cert?.headline ?: "Checking…")
         }
-        val navigator = LocalCarNavigator.current
-        Button(onClick = { navigator.open("calibrate") }) { Text("Display test") }
-        Spacer(Modifier.height(8.dp))
+
+        Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+            Text("About", style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
+            Info("Version", app.seb3thehacker.gearslip.BuildConfig.VERSION_NAME)
+            Info("Build", app.seb3thehacker.gearslip.BuildConfig.VERSION_CODE.toString())
+            ExperimentalFeatureRow(
+                "What's new after updates",
+                "Show the list of changes once, the first time the car connects after an update.",
+                whatsNew,
+            ) { CarSettings.setWhatsNewAfterUpdates(it) }
+            GsButton(onClick = CarSettings::openWhatsNew, tone = GsTone.Tonal, modifier = Modifier.height(56.dp)) {
+                Text("What's new", style = MaterialTheme.typography.titleMedium)
+            }
+        }
     }
 }
 
@@ -130,25 +216,80 @@ private fun <T> ChoiceRow(title: String, options: List<Pair<T, String>>, selecte
         Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(12.dp)) {
             options.forEach { (value, label) ->
                 val on = value == selected
-                Surface(
+                val scheme = MaterialTheme.colorScheme
+                GsIconBox(
                     onClick = { onSelect(value) },
                     modifier = Modifier
                         .weight(1f)
                         .height(64.dp),
-                    shape = MaterialTheme.shapes.large,
-                    color = if (on) MaterialTheme.colorScheme.primaryContainer else MaterialTheme.colorScheme.surfaceContainerHigh,
-                    contentColor = if (on) MaterialTheme.colorScheme.onPrimaryContainer else MaterialTheme.colorScheme.onSurface,
+                    colors = if (on) GsColors(scheme.primaryContainer, scheme.onPrimaryContainer)
+                    else GsColors(scheme.surfaceContainerHigh, scheme.onSurface),
+                    latched = on,
                 ) {
-                    Row(Modifier.fillMaxSize(), verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.Center) {
-                        Text(label, style = MaterialTheme.typography.titleMedium, fontWeight = if (on) FontWeight.Bold else FontWeight.Normal)
-                    }
+                    Text(label, style = MaterialTheme.typography.titleMedium, fontWeight = if (on) FontWeight.Bold else FontWeight.Normal)
                 }
             }
         }
     }
 }
 
-/** The URL (or raw HTML) the Web app shows. Edited with [CarKeyboard] - no phone in hand needed. */
+/**
+ * Individually-switched experimental features, shown once the driver has opted into
+ * experimental features as a whole. Each is its own row - a title, what it does, and a switch -
+ * so the list reads fine whether there's one entry or several.
+ */
+@Composable
+private fun ExperimentalFeaturesList(carSensors: Boolean) {
+    Column(
+        Modifier.fillMaxWidth(),
+        verticalArrangement = Arrangement.spacedBy(10.dp),
+    ) {
+        ExperimentalFeatureRow(
+            title = "Vehicle data",
+            description = "Adds a Vehicle data tile: a live, raw dump of the head unit's sensor " +
+                "channel. Field labels (speed, RPM, fuel...) are carried over from other " +
+                "reverse-engineering projects and unverified against this car - treat them as a " +
+                "guess, not a fact, until you've watched one change for yourself.",
+            checked = carSensors,
+        ) { CarSettings.setCarSensorsEnabled(it) }
+    }
+}
+
+@Composable
+private fun ExperimentalFeatureRow(
+    title: String,
+    description: String,
+    checked: Boolean,
+    warning: Boolean = false,
+    onCheckedChange: (Boolean) -> Unit,
+) {
+    Surface(
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(
+            Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 16.dp, vertical = 12.dp),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Column(Modifier.weight(1f)) {
+                Text(title, style = MaterialTheme.typography.titleMedium)
+                Text(
+                    description,
+                    style = MaterialTheme.typography.bodySmall,
+                    color = if (warning) MaterialTheme.colorScheme.error else MaterialTheme.colorScheme.onSurfaceVariant,
+                    modifier = Modifier.padding(top = 2.dp),
+                )
+            }
+            Spacer(Modifier.width(12.dp))
+            GsSwitch(checked, onCheckedChange)
+        }
+    }
+}
+
+/** The URL (or raw HTML) the Browser app shows. Edited with [CarKeyboard] - no phone in hand needed. */
 @Composable
 private fun WebPageSetting() {
     val context = LocalContext.current
@@ -173,7 +314,7 @@ private fun WebPageSetting() {
             )
         }
         Text(
-            "Shown by the Web app on the launcher. Applies on the next connection.",
+            "Shown by the Browser app on the launcher. Applies on the next connection.",
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
@@ -185,6 +326,7 @@ private fun WebPageSetting() {
                     AppSettings.setStartupUrl(context, it)
                 },
                 onSubmit = { editing = false },
+                onDismiss = { editing = false },
             )
         }
     }
@@ -223,7 +365,7 @@ private fun ScreenFit(vehicle: String) {
             style = MaterialTheme.typography.bodyMedium,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
-        Button(
+        GsButton(
             onClick = {
                 val ok = app.seb3thehacker.gearslip.VehicleProfiles.saveInsets(context, vehicle, insets)
                 saved = if (ok) "Saved to $vehicle" else "Could not save"
@@ -254,14 +396,13 @@ private fun Stepper(label: String, value: Int, onStep: (Int) -> Unit) {
 
 @Composable
 private fun StepButton(text: String, modifier: Modifier, onClick: () -> Unit) {
-    Surface(
+    GsIconBox(
         onClick = onClick,
         modifier = modifier.height(64.dp),
+        colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHigh, MaterialTheme.colorScheme.onSurface),
         shape = MaterialTheme.shapes.large,
-        color = MaterialTheme.colorScheme.surfaceContainerHigh,
     ) {
-        Row(Modifier.fillMaxSize(), horizontalArrangement = Arrangement.Center, verticalAlignment = Alignment.CenterVertically) {
-            Text(text, style = MaterialTheme.typography.titleLarge)
-        }
+        Text(text, style = MaterialTheme.typography.titleLarge)
     }
 }
+

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarToastOverlay.kt

@@ -0,0 +1,62 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.platform.LocalAccessibilityManager
+import androidx.compose.ui.semantics.LiveRegionMode
+import androidx.compose.ui.semantics.liveRegion
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.withTimeoutOrNull
+
+/** Draw inside the encoded car display; a normal Android Toast would appear on the phone. */
+@Composable
+internal fun CarToastOverlay(modifier: Modifier = Modifier) {
+    val current by CarToasts.message.collectAsState()
+    val message = current ?: return
+    val accessibility = LocalAccessibilityManager.current
+    LaunchedEffect(message, accessibility) {
+        val timeout = accessibility?.calculateRecommendedTimeoutMillis(
+            message.durationMs, containsIcons = false, containsText = true, containsControls = false,
+        ) ?: message.durationMs
+        // The full time, unless another toast is waiting: then it gives way after the minimum.
+        delay(minOf(timeout, CarToasts.MIN_SHOWN_MS))
+        withTimeoutOrNull((timeout - CarToasts.MIN_SHOWN_MS).coerceAtLeast(0)) {
+            CarToasts.waiting.first { it > 0 }
+        }
+        CarToasts.dismiss(message)
+    }
+
+    // A non-interactive overlay leaves the map's touch handling and focus intact.
+    Box(
+        modifier
+            .padding(horizontal = 24.dp, vertical = 16.dp)
+            .widthIn(max = 560.dp)
+            .clip(RoundedCornerShape(20.dp))
+            .background(MaterialTheme.colorScheme.surfaceContainerHigh)
+            .semantics { liveRegion = LiveRegionMode.Polite },
+    ) {
+        Text(
+            message.text,
+            modifier = Modifier.padding(horizontal = 20.dp, vertical = 12.dp),
+            color = MaterialTheme.colorScheme.onSurface,
+            style = MaterialTheme.typography.titleMedium,
+            maxLines = 3,
+            overflow = TextOverflow.Ellipsis,
+        )
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarToasts.kt

@@ -0,0 +1,65 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.annotation.MainThread
+import androidx.car.app.CarToast
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/**
+ * One toast at a time across navigation and browse apps. A newer one waits its turn instead of
+ * replacing the one on screen, which gets at least [MIN_SHOWN_MS] before it gives way.
+ */
+@MainThread
+internal object CarToasts {
+    // Identity matters: repeating identical text must restart its display timer.
+    class Message(val owner: Any, val text: String, val durationMs: Long)
+
+    /** Long enough to read a short toast at a glance; a waiting toast cuts the rest short. */
+    const val MIN_SHOWN_MS = 2_000L
+
+    /** A burst beyond this many is stale by the time it would show; the oldest waiting go first. */
+    private const val MAX_WAITING = 3
+
+    private val current = MutableStateFlow<Message?>(null)
+    val message: StateFlow<Message?> = current.asStateFlow()
+
+    private val queue = ArrayDeque<Message>()
+    private val _waiting = MutableStateFlow(0)
+    val waiting: StateFlow<Int> = _waiting.asStateFlow()
+
+    fun show(owner: Any, text: String, duration: Int) {
+        if (text.isBlank()) return
+        // Longer than a phone toast: the driver only glances at the screen now and then.
+        val durationMs = if (duration == CarToast.LENGTH_LONG) 7_000L else 4_000L
+        val next = Message(owner, text, durationMs)
+        val shown = current.value
+        when {
+            shown == null -> current.value = next
+            // The same words again restart the one on screen rather than queueing a copy.
+            shown.text == text -> current.value = next
+            queue.lastOrNull()?.text == text -> Unit
+            else -> {
+                queue.addLast(next)
+                while (queue.size > MAX_WAITING) queue.removeFirst()
+            }
+        }
+        _waiting.value = queue.size
+    }
+
+    fun dismiss(message: Message) {
+        // An old timer must not dismiss a newer toast, even if its text is identical.
+        if (current.value === message) advance()
+    }
+
+    fun clear(owner: Any) {
+        // Disconnecting the map must not clear a toast belonging to the browse app.
+        queue.removeAll { it.owner === owner }
+        if (current.value?.owner === owner) advance() else _waiting.value = queue.size
+    }
+
+    private fun advance() {
+        current.value = queue.removeFirstOrNull()
+        _waiting.value = queue.size
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarUi.kt

@@ -2,8 +2,10 @@ package app.seb3thehacker.gearslip.car
 
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.LocalIndication
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
@@ -12,19 +14,29 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.offset
-import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.background
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.ui.graphics.lerp
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.border
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.Notifications
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.foundation.layout.BoxScope
+import androidx.car.app.model.CarIcon
+import androidx.car.app.navigation.model.NavigationTemplate
+import androidx.car.app.navigation.model.RoutingInfo
+import app.seb3thehacker.gearslip.host.CarAppConnection
+import app.seb3thehacker.gearslip.host.display
+import app.seb3thehacker.gearslip.host.text
+import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material.icons.filled.PlayArrow
-import androidx.compose.material.icons.filled.Home
-import androidx.compose.material3.FilledIconButton
 import androidx.compose.material3.Icon
-import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
@@ -32,22 +44,41 @@ import androidx.compose.material3.dynamicDarkColorScheme
 import androidx.compose.material3.dynamicLightColorScheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.hapticfeedback.HapticFeedback
+import androidx.compose.ui.hapticfeedback.HapticFeedbackType
+import androidx.compose.ui.platform.LocalHapticFeedback
+import androidx.compose.ui.platform.LocalView
 import androidx.compose.runtime.State
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.produceState
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.compose.animation.animateContentSize
+import android.media.session.PlaybackState
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.input.pointer.PointerEventPass
 import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.res.vectorResource
 import androidx.compose.ui.text.style.TextOverflow
+import app.seb3thehacker.gearslip.R
+import app.seb3thehacker.gearslip.car.theme.GsColors
+import app.seb3thehacker.gearslip.car.theme.GsIconBox
+import app.seb3thehacker.gearslip.car.theme.GsIconButton
+import app.seb3thehacker.gearslip.car.theme.GsButton
+import app.seb3thehacker.gearslip.car.theme.GsTone
+import app.seb3thehacker.gearslip.car.theme.gsColors
+import app.seb3thehacker.gearslip.car.theme.GsThemes
+import app.seb3thehacker.gearslip.car.theme.LocalGsTheme
 import app.seb3thehacker.gearslip.media.CarMedia
 import app.seb3thehacker.gearslip.media.MediaArt
 import androidx.compose.ui.platform.LocalContext
@@ -56,7 +87,10 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.Density
 import androidx.compose.ui.unit.dp
 import app.seb3thehacker.gearslip.notify.CarNotifications
+import androidx.core.graphics.drawable.toBitmap
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.withContext
 import java.text.DateFormat
 import java.util.Date
 
@@ -71,6 +105,7 @@ fun CarUi() {
     val scale by CarSettings.scale.collectAsState()
     val phoneDark by CarEnvironment.phoneDark.collectAsState()
     val appTheme by CarSettings.appTheme.collectAsState()
+    val uiThemeId by CarSettings.uiTheme.collectAsState()
     val mediaApp by CarServices.mediaApp.collectAsState()
     val darkOutside by CarEnvironment.darkOutside.collectAsState()
     val appContext = LocalContext.current.applicationContext
@@ -90,18 +125,69 @@ fun CarUi() {
             controlsWake.tick()
         }
     }
+    // The knob counts as a touch: the map's buttons can't be found while they're faded out.
+    LaunchedEffect(controlsWake) { CarKeys.focusMoves.collect { controlsWake.touch() } }
     remember(appContext) { Prefetch.warm(appContext, force = true); CarServices.init(appContext) }
     DisposableEffect(Unit) { onDispose { CarServices.shutdown() } }
+    // Ask for the phone's sound as soon as the car connects, not only when a media app opens:
+    // a video in the web browser or a map's voice needs it too. Asks once, after the car offers
+    // somewhere to play it.
+    LaunchedEffect(Unit) { if (CarSettings.pipeAudio.value) app.seb3thehacker.gearslip.audio.CarAudio.request() }
+    // A new version gets one card in the top right, a few seconds in and only while parked.
+    LaunchedEffect(Unit) { app.seb3thehacker.gearslip.update.UpdateChecker.onCarConnected(appContext) }
     // The map follows the light outside, whatever the app's own theme is set to.
     LaunchedEffect(darkOutside) { CarServices.nav.pushConfiguration() }
 
+    // The one place with a navigator and a frame to act a voice command on - CarAssistant itself
+    // only knows how to listen and speak, not what "open Spotify" means.
+    val frameForAssistant by CarEnvironment.frame.collectAsState()
+    LaunchedEffect(navigator) {
+        CarAssistant.pendingCommand.collect { heard ->
+            if (heard != null) {
+                val reply = AssistantCommands.handle(appContext, navigator, frameForAssistant, heard)
+                CarAssistant.reply(reply)
+            }
+        }
+    }
+
+    // The car's own back, home, map, media and phone keys.
+    LaunchedEffect(navigator) {
+        CarKeys.screenKeys.collect { key ->
+            when (key) {
+                CarKeys.ScreenKey.BACK -> when {
+                    navigator.appMenu != null -> navigator.dismissAppMenu()
+                    VoiceReply.state.value.phase != VoiceReply.Phase.IDLE -> VoiceReply.cancel()
+                    else -> navigator.back()
+                }
+                // Home is the dashboard, over the map, so Back from it lands on the map.
+                CarKeys.ScreenKey.HOME -> { navigator.home(); navigator.dashboard() }
+                CarKeys.ScreenKey.MAP -> navigator.home()
+                CarKeys.ScreenKey.MEDIA ->
+                    if (CarServices.mediaApp.value != null || CarServices.reopenLastMedia()) navigator.media()
+                    else navigator.apps()
+                CarKeys.ScreenKey.PHONE -> BuiltInApps.Phone.open(navigator)
+            }
+        }
+    }
+
+    // The car screen is drawn on the phone, so every long press or text-handle drag would buzz
+    // the phone in its mount. Nobody feels that while driving; it's only noise.
+    val view = LocalView.current
+    DisposableEffect(view) {
+        view.isHapticFeedbackEnabled = false
+        onDispose { }
+    }
+
     CompositionLocalProvider(
+        LocalHapticFeedback provides NoHaptics,
         LocalDensity provides Density(base.density * scale, base.fontScale),
         LocalCarNavigator provides navigator,
         LocalDarkOutside provides darkOutside,
         LocalMapControlsWake provides controlsWake,
+        LocalGsTheme provides GsThemes.byId(uiThemeId),
     ) {
         MaterialTheme(colorScheme = colors) {
+          CompositionLocalProvider(LocalIndication provides FocusRingIndication(MaterialTheme.colorScheme.primary)) {
             Surface(
                 Modifier
                     .fillMaxSize()
@@ -123,29 +209,341 @@ fun CarUi() {
                         end = insets.right.toDp(), bottom = insets.bottom.toDp(),
                     )
                 }
-                // The calibration screen is the raw frame: no insets, no nav bar.
                 val screen = navigator.current
-                if (screen == CarScreen.App("calibrate")) {
-                    CarApps.find("calibrate")?.content?.invoke()
-                } else {
-                    Column(Modifier.fillMaxSize().padding(pad)) {
-                        Box(Modifier.weight(1f).fillMaxWidth()) {
-                            when (screen) {
-                                CarScreen.Home -> CarHome()
-                                CarScreen.Apps -> CarLauncher()
-                                CarScreen.Media -> mediaApp?.let { MediaScreen(it) { navigator.home() } }
-                                CarScreen.Settings -> CarSettingsScreen()
-                                CarScreen.Dashboard -> CarDashboardScreen()
-                                CarScreen.Weather -> WeatherScreen()
-                                is CarScreen.Notifications -> NotificationsScreen(screen.replyTo)
-                                is CarScreen.App -> CarApps.find(screen.id)?.content?.invoke()
+                val safetyWarningSeen by CarSettings.hasSeenSafetyWarning.collectAsState()
+                Box(Modifier.fillMaxSize().padding(pad)) {
+                Column(Modifier.fillMaxSize()) {
+                    if (!safetyWarningSeen) {
+                        CarSafetyWizard(onDone = CarSettings::markSafetyWarningSeen)
+                        return@Column
+                    }
+                    // Header navigation (breadcrumb trail) - off for now, kept to tweak later.
+                    // BreadcrumbBar(navigator)
+                    Box(Modifier.weight(1f).fillMaxWidth()) {
+                        // Home never leaves the composition; other screens cover it. Dropping it
+                        // would tear down the map's surface, and coming back would then show black
+                        // while the nav app redrew on a new one.
+                        CarHome()
+                        if (screen != CarScreen.Home) {
+                            Box(
+                                Modifier
+                                    .fillMaxSize()
+                                    .background(MaterialTheme.colorScheme.background)
+                                    // Keeps touches that miss this screen's controls off the map.
+                                    .pointerInput(Unit) { detectTapGestures { } },
+                            ) {
+                                when (screen) {
+                                    CarScreen.Home -> Unit
+                                    CarScreen.Apps -> CarLauncher()
+                                    CarScreen.Media -> mediaApp?.let { MediaScreen(it) { navigator.back() } }
+                                    CarScreen.Browse -> BrowseAppScreen(navigator)
+                                    CarScreen.Settings -> CarSettingsScreen()
+                                    CarScreen.Dashboard -> CarDashboardScreen()
+                                    CarScreen.Weather -> WeatherScreen()
+                                    CarScreen.VehicleData -> VehicleDataScreen()
+                                    is CarScreen.Notifications -> NotificationsScreen(screen.replyTo)
+                                    is CarScreen.Messages -> MessagesScreen(screen.packageName)
+                                    is CarScreen.App -> CarApps.find(screen.id)?.content?.invoke()
+                                }
                             }
-                            // The history screen is already showing them, so it needs no popup.
-                            if (screen !is CarScreen.Notifications) {
-                                NotificationPopup(Modifier.align(Alignment.TopCenter))
+                        }
+                        CarToastOverlay(Modifier.align(Alignment.BottomCenter))
+                        CallPromptOverlay()
+                        BluetoothPairOverlay()
+                        PopupTimer()
+                        // The dashboard is already listing them, so it needs no popup.
+                        NotificationPopup(
+                            showNew = screen !is CarScreen.Notifications && screen != CarScreen.Dashboard,
+                            modifier = Modifier.align(Alignment.TopEnd),
+                        )
+                        // Above the popup: a call is more urgent than any notification.
+                        VoiceHelpOverlay(Modifier.align(Alignment.Center))
+                        CallOverlay(Modifier.align(Alignment.TopCenter))
+                        AssistantOverlay(Modifier.align(Alignment.BottomCenter))
+                        if (app.seb3thehacker.gearslip.BuildConfig.DEBUG) {
+                            // Bottom corner, not top: a screen's own header almost always puts
+                            // something in the top-right (settings, search, a Liked Songs
+                            // shortcut) and this badge used to sit right on top of it, hiding
+                            // whatever the screen drew there.
+                            DebugBuildBadge(Modifier.align(Alignment.BottomEnd))
+                        }
+                    }
+                    // The keyboard takes the nav bar's row instead of squeezing in above it -
+                    // nothing on the nav bar is useful mid-type, and the screen is too small to
+                    // show both.
+                    val keyboardVisible by CarKeyboardVisibility.state
+                    if (!keyboardVisible) CarNavBar(navigator)
+                }
+                // Over everything, nav bar included: a long press on an app, anywhere.
+                AppMenu(navigator, rememberRunningApps())
+                if (safetyWarningSeen) CarWhatsNew()
+                }
+            }
+          }
+        }
+    }
+}
+
+/**
+ * A single blocking screen, shown once per install before anything else the car screen can show -
+ * Home included. The phone's own setup guide carries the same warning, but a driver who plugs in
+ * without ever opening the phone app would otherwise never see it, on the one screen they are
+ * actually about to use while driving. [onDone] fires once, from its own button; there is no way
+ * to skip past this without tapping it.
+ */
+@Composable
+private fun CarSafetyWizard(onDone: () -> Unit) {
+    Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+        // The card and its button share one width, capped so neither sprawls across a wide screen.
+        Column(
+            Modifier.widthIn(max = 640.dp).fillMaxWidth().padding(24.dp),
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            Surface(
+                color = MaterialTheme.colorScheme.surfaceContainerLow,
+                shape = MaterialTheme.shapes.extraLarge,
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                Column(Modifier.padding(24.dp), verticalArrangement = Arrangement.spacedBy(12.dp)) {
+                    Text("Drive safely", style = ChromeType.headline, fontWeight = FontWeight.Bold)
+                    Text(
+                        "Gearslip is unofficial software: it is not made or reviewed by any " +
+                            "carmaker, and it can fail without warning.",
+                        style = ChromeType.body,
+                    )
+                    Text(
+                        "Never interact with this screen while driving. Set the route or the " +
+                            "song before you go, then keep your attention on the road.",
+                        style = ChromeType.body,
+                    )
+                }
+            }
+            Spacer(Modifier.height(24.dp))
+            GsButton(onClick = onDone, modifier = Modifier.fillMaxWidth().height(56.dp)) {
+                Text("I understand", style = ChromeType.body)
+            }
+        }
+    }
+}
+
+/**
+ * A templated app that isn't navigation, full size with its own title bar and Stop button - the
+ * same [CarAppStage] chrome the map uses on Home, just not embedded there. [CarServices.browse]
+ * is a connection of its own, so opening one of these never bumps the map off Home.
+ */
+@Composable
+private fun BrowseAppScreen(navigator: CarNavigator) {
+    val status by CarServices.browse.status.collectAsState()
+    val frame by CarEnvironment.frame.collectAsState()
+    val template by CarServices.browse.template.collectAsState()
+    val leave = {
+        CarServices.stopBrowse()
+        navigator.back()
+    }
+    // An app that never answers is as stuck as one that says no; don't leave the driver on "Loading".
+    var timedOut by remember { mutableStateOf(false) }
+    LaunchedEffect(template == null) {
+        timedOut = false
+        if (template == null) {
+            delay(APP_START_TIMEOUT_MS)
+            timedOut = true
+        }
+    }
+    val failed = status.phase == CarAppConnection.Phase.REJECTED || status.phase == CarAppConnection.Phase.FAILED
+    if (failed || timedOut) {
+        AppWontStart(status.app ?: "This app", leave)
+        return
+    }
+    CarAppStage(CarServices.browse, status, frame, onDisconnect = leave)
+}
+
+private const val APP_START_TIMEOUT_MS = 15_000L
+
+/** What a car app that won't run under Gearslip gets instead of a loading screen that never ends. */
+@Composable
+private fun AppWontStart(app: String, onBack: () -> Unit) {
+    Column(
+        Modifier.fillMaxSize().padding(24.dp),
+        verticalArrangement = Arrangement.spacedBy(12.dp, Alignment.CenterVertically),
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Text("$app doesn't work with Gearslip yet.", style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.SemiBold)
+        Text(
+            "It didn't start. Some apps only run on Google's Android Auto.",
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+        GsButton(onClick = onBack, tone = GsTone.Tonal) { Text("Back") }
+    }
+}
+
+/**
+ * Marks a debug build on the car screen itself, not just the phone's Home screen - the one
+ * that matters while driving, since a debug build is slower and less tested than what ships.
+ */
+@Composable
+private fun DebugBuildBadge(modifier: Modifier = Modifier) {
+    Surface(
+        modifier = modifier.padding(6.dp),
+        color = MaterialTheme.colorScheme.error,
+        contentColor = MaterialTheme.colorScheme.onError,
+        shape = MaterialTheme.shapes.small,
+    ) {
+        Text(
+            "DEBUG BUILD",
+            style = MaterialTheme.typography.labelSmall,
+            fontWeight = FontWeight.Bold,
+            modifier = Modifier.padding(horizontal = 8.dp, vertical = 3.dp),
+        )
+    }
+}
+
+/**
+ * "Home > Apps > Settings", like a file manager's address bar: hidden at Home itself (nothing to
+ * show yet), and grows by one crumb for every screen pushed from there. The back arrow undoes one
+ * step; a crumb jumps straight to it, dropping everything after - this is the only on-screen way
+ * back at all, since a car touchscreen has no hardware button for it.
+ */
+@Composable
+private fun BreadcrumbBar(navigator: CarNavigator) {
+    val trail = navigator.trail
+    if (trail.size <= 1) return
+    Row(
+        Modifier.fillMaxWidth().height(40.dp).padding(start = 2.dp, end = 10.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        GsIconButton(Icons.AutoMirrored.Filled.ArrowBack, "Back", navigator::back, size = 32.dp, iconSize = 20.dp)
+        Spacer(Modifier.width(2.dp))
+        trail.forEachIndexed { index, crumb ->
+            val isLast = index == trail.lastIndex
+            Text(
+                crumb.label,
+                style = MaterialTheme.typography.labelLarge,
+                fontWeight = if (isLast) FontWeight.SemiBold else FontWeight.Normal,
+                color = if (isLast) MaterialTheme.colorScheme.onSurface else MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = if (isLast) Modifier else Modifier
+                    .clip(RoundedCornerShape(6.dp))
+                    .clickable { navigator.jumpTo(index) }
+                    .padding(horizontal = 4.dp, vertical = 2.dp),
+            )
+            if (!isLast) {
+                Text(
+                    "›",
+                    style = MaterialTheme.typography.labelLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    modifier = Modifier.padding(horizontal = 2.dp),
+                )
+            }
+        }
+    }
+}
+
+/**
+ * Apps and open/pinned shortcuts on the left; now-playing pill against them; clock (tap for
+ * calendar and weather), phone battery and the darkness signal on the right. Icon-only: a driver
+ * reads a glyph faster than a label, and it keeps the bar short enough to leave the app underneath
+ * more room.
+ */
+@Composable
+private fun CarNavBar(navigator: CarNavigator) {
+    val battery by CarEnvironment.battery.collectAsState()
+    val now by rememberNow()
+    val weather by Weather.state.collectAsState()
+    val weatherData = (weather as? WeatherState.Ready)?.data
+
+    val pinnedIds by CarSettings.pinnedApps.collectAsState()
+    val entries = rememberAllEntries()
+    val pinnedEntries = remember(entries, pinnedIds) {
+        pinnedIds.mapNotNull { id -> entries.find { it.componentId == id } }
+    }
+    val frame by CarEnvironment.frame.collectAsState()
+    val running = rememberRunningApps()
+
+    Surface(color = MaterialTheme.colorScheme.surfaceContainer) {
+        BoxWithConstraints(Modifier.fillMaxWidth().height(56.dp).padding(horizontal = 10.dp)) {
+            Row(Modifier.fillMaxSize(), verticalAlignment = Alignment.CenterVertically) {
+                // Home and Apps are two different places now, not a toggle on one button - the
+                // breadcrumb trail is how you retrace your steps, but reaching for either of
+                // these two from three screens deep in a media app shouldn't mean reading it
+                // first.
+                NavHomeButton(navigator, entries, running)
+                Spacer(Modifier.width(6.dp))
+                NavItem(MediaIcons.Apps, navigator.current == CarScreen.Apps) { navigator.apps() }
+                Spacer(Modifier.width(6.dp))
+                NavAssistantIcon()
+
+                // Pinned shortcuts, then whatever else is open right now. A pinned app that's also
+                // open stays in its pinned spot, marked with a dot, instead of showing up twice.
+                // The map app lives on the Home button, so it never gets a second icon here.
+                val runningEntries = running.keys
+                    .filter { it !in pinnedIds && running[it] != RunningSlot.NAV }
+                    .mapNotNull { id -> entries.find { it.componentId == id } }
+                val shownPins = pinnedEntries.filter { running[it.componentId] != RunningSlot.NAV }
+                if (shownPins.isNotEmpty() || runningEntries.isNotEmpty()) NavDivider()
+                shownPins.forEach { entry -> NavEntryIcon(entry, running, navigator, frame) }
+                if (shownPins.isNotEmpty() && runningEntries.isNotEmpty()) NavDivider()
+                runningEntries.forEach { entry -> NavEntryIcon(entry, running, navigator, frame) }
+
+                // Next turn first, off the map only; the player shares the space when it fits,
+                // and gives way to the turn when it doesn't.
+                val turn = rememberNextTurn().takeIf { navigator.current != CarScreen.Home }
+                BoxWithConstraints(Modifier.weight(1f).padding(horizontal = 16.dp), contentAlignment = Alignment.Center) {
+                    val roomForBoth = maxWidth >= TURN_AND_PLAYER_MIN_WIDTH
+                    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+                        turn?.let { NavTurnPill(it) { navigator.home() } }
+                        if (turn == null || roomForBoth) {
+                            NavNowPlaying(navigator, selected = navigator.current == CarScreen.Media, modifier = Modifier.weight(1f, fill = false))
+                        }
+                    }
+                }
+
+                // Weather no longer has its own chip - the temperature alone (no icon, no room
+                // for one) sits where "Night"/"Day" used to, freeing a whole chip's width for the
+                // Home button above.
+                // The clock is also the notifications button: the dashboard lists them under the
+                // calendar and weather, and a dot here marks anything unread.
+                val unread by CarNotifications.unread.collectAsState()
+                NavChip(
+                    navigator.current == CarScreen.Dashboard || navigator.current is CarScreen.Notifications,
+                    { navigator.dashboard() },
+                ) {
+                    if (unread > 0) {
+                        Box(
+                            Modifier
+                                .align(Alignment.TopEnd)
+                                .offset(x = 8.dp, y = (-2).dp)
+                                .size(8.dp)
+                                .clip(CircleShape)
+                                .background(MaterialTheme.colorScheme.primary),
+                        )
+                    }
+                    Column(horizontalAlignment = Alignment.End) {
+                        Text(
+                            DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(now)),
+                            style = MaterialTheme.typography.titleMedium,
+                            fontWeight = FontWeight.SemiBold,
+                        )
+                        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(3.dp)) {
+                            if (battery.percent >= 0) {
+                                Text(
+                                    "${battery.percent}%",
+                                    style = MaterialTheme.typography.labelMedium,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                )
+                                if (battery.charging) {
+                                    ChargingGlyph(Modifier.size(13.dp))
+                                }
+                            }
+                            weatherData?.let { w ->
+                                Text(
+                                    "  ·  ${w.temp}°",
+                                    style = MaterialTheme.typography.labelMedium,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                )
                             }
                         }
-                        CarNavBar(navigator)
                     }
                 }
             }
@@ -154,94 +552,140 @@ fun CarUi() {
 }
 
 /**
- * Home and Apps on the left; now-playing pill in the middle; clock (tap for calendar and weather), phone battery and the
- * darkness signal on the right. Icon-only: a driver reads a glyph faster than a label, and it
- * keeps the bar short enough to leave the app underneath more room.
+ * Home: the map, with the player or lyrics beside it. While a map app runs, the button wears that
+ * app's icon and a long press offers to close it, so the app needs no icon of its own on the bar.
  */
 @Composable
-private fun CarNavBar(navigator: CarNavigator) {
-    val battery by CarEnvironment.battery.collectAsState()
-    val darkOutside by CarEnvironment.darkOutside.collectAsState()
-    val now by rememberNow()
-
-    // The home screen shows what's playing itself, unless it was minimised; everywhere else it lives in this bar.
-    val showNowPlaying = navigator.current != CarScreen.Home || navigator.playerMinimised
-    val weather by Weather.state.collectAsState()
-
-    // One row, so nothing can sit on top of anything else: the player takes whatever width the
-    // fixed items leave and shortens its title to fit.
-    Surface(color = MaterialTheme.colorScheme.surfaceContainer) {
-        Row(
-            Modifier.fillMaxWidth().height(56.dp).padding(horizontal = 10.dp),
-            verticalAlignment = Alignment.CenterVertically,
-        ) {
-            NavItem(Icons.Filled.Home, navigator.current == CarScreen.Home) { navigator.home() }
-            Spacer(Modifier.width(6.dp))
-            NavItem(MediaIcons.Apps, navigator.current == CarScreen.Apps) { navigator.apps() }
-
-            Box(Modifier.weight(1f).padding(horizontal = 10.dp), contentAlignment = Alignment.CenterStart) {
-                if (showNowPlaying) NavNowPlaying(navigator, selected = navigator.current == CarScreen.Media)
+private fun NavHomeButton(navigator: CarNavigator, entries: List<Entry>, running: Map<String, RunningSlot>) {
+    val selected = navigator.current == CarScreen.Home
+    val navId = running.entries.firstOrNull { it.value == RunningSlot.NAV }?.key
+    val navEntry = navId?.let { id -> entries.find { it.componentId == id } }
+    GsIconBox(
+        { navigator.home() },
+        colors = navColors(selected),
+        latched = selected,
+        onLongClick = navId?.let { id -> { navigator.showAppMenu(id) } },
+    ) {
+        val icon = navEntry?.icon
+        if (icon != null) {
+            Box(Modifier.padding(NAV_ITEM_PADDING).size(28.dp), contentAlignment = Alignment.Center) {
+                Image(icon, navEntry.label, Modifier.size(28.dp).clip(RoundedCornerShape(7.dp)))
             }
+        } else {
+            Icon(
+                ImageVector.vectorResource(R.drawable.navigation_24), contentDescription = "Home",
+                modifier = Modifier.padding(NAV_ITEM_PADDING).size(28.dp),
+            )
+        }
+    }
+}
 
-            (weather as? WeatherState.Ready)?.data?.let { w ->
-                NavChip(navigator.current == CarScreen.Weather, { navigator.weather() }) {
-                    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(6.dp)) {
-                        WeatherIcon(w.code, w.isDay, size = 28.dp)
-                        Text("${w.temp}°", style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
-                    }
-                }
-                Spacer(Modifier.width(4.dp))
-            }
-            NavChip(navigator.current == CarScreen.Dashboard, { navigator.dashboard() }) {
-                Column(horizontalAlignment = Alignment.End) {
-                    Text(
-                        DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(now)),
-                        style = MaterialTheme.typography.titleMedium,
-                        fontWeight = FontWeight.SemiBold,
-                    )
-                    val phone = if (battery.percent >= 0) "${battery.percent}%${if (battery.charging) " charging" else ""}" else ""
-                    val light = if (darkOutside) "Night" else "Day"
-                    Text(
-                        listOf(phone, light).filter { it.isNotEmpty() }.joinToString("  ·  "),
-                        style = MaterialTheme.typography.labelMedium,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    )
-                }
-            }
-            Spacer(Modifier.width(10.dp))
-            NavItem(
-                Icons.Filled.Notifications, navigator.current is CarScreen.Notifications,
-            ) { navigator.notifications() }
+/** Splits the nav bar's sections: Home and Apps, pinned apps, open apps. */
+@Composable
+private fun NavDivider() {
+    Box(
+        Modifier
+            .padding(horizontal = 10.dp)
+            .width(1.dp)
+            .height(28.dp)
+            .background(MaterialTheme.colorScheme.outlineVariant),
+    )
+}
+
+/**
+ * A pinned or open app on the nav bar. Tapping brings it back without reconnecting if it's
+ * already open; a long press opens its menu (pin, unpin, close).
+ */
+@Composable
+private fun NavEntryIcon(
+    entry: Entry,
+    running: Map<String, RunningSlot>,
+    navigator: CarNavigator,
+    frame: CarEnvironment.Frame,
+) {
+    val id = entry.componentId ?: return
+    val slot = running[id]
+    Box(Modifier.padding(horizontal = 3.dp)) {
+        NavAppIcon(
+            entry,
+            open = slot != null,
+            showing = slot != null && slot.isShowing(navigator.current),
+            onLongClick = { navigator.showAppMenu(id) },
+        ) { openApp(entry, slot, navigator, frame) }
+    }
+}
+
+/** One open or pinned app's icon on the nav bar - the same fixed size and shape either way. */
+@Composable
+private fun NavAppIcon(
+    entry: Entry,
+    open: Boolean,
+    showing: Boolean,
+    onLongClick: () -> Unit,
+    onClick: () -> Unit,
+) {
+    val scheme = MaterialTheme.colorScheme
+    GsIconBox(
+        onClick,
+        Modifier.size(44.dp),
+        colors = if (showing) GsColors(scheme.secondaryContainer, scheme.onSecondaryContainer)
+        else GsColors(scheme.surfaceVariant, scheme.onSurfaceVariant),
+        latched = showing,
+        onLongClick = onLongClick,
+    ) {
+        entry.icon?.let { Image(it, entry.label, Modifier.size(30.dp).clip(RoundedCornerShape(8.dp))) }
+        entry.builtIn?.let { Icon(it.glyph, entry.label, Modifier.size(26.dp)) }
+        // Only running apps get the line along the bottom edge, the usual taskbar mark for it.
+        if (open) {
+            Box(
+                Modifier
+                    .align(Alignment.BottomCenter)
+                    .padding(bottom = 2.dp)
+                    .size(width = 12.dp, height = 3.dp)
+                    .clip(RoundedCornerShape(50))
+                    .background(scheme.primary),
+            )
         }
     }
 }
 
 /** A tappable group in the bar that stays highlighted while its screen is open, like [NavItem]. */
 @Composable
-private fun NavChip(selected: Boolean, onClick: () -> Unit, content: @Composable () -> Unit) {
-    val scheme = MaterialTheme.colorScheme
-    Box(
-        Modifier
-            .clip(RoundedCornerShape(18.dp))
-            .background(if (selected) scheme.secondaryContainer else scheme.surfaceContainer)
-            .clickable(onClick = onClick)
-            .padding(horizontal = 10.dp, vertical = 6.dp),
-        contentAlignment = Alignment.Center,
-    ) { content() }
+private fun NavChip(selected: Boolean, onClick: () -> Unit, content: @Composable BoxScope.() -> Unit) {
+    GsIconBox(onClick, colors = navColors(selected), latched = selected) {
+        Box(Modifier.padding(horizontal = 10.dp, vertical = 2.dp)) { content() }
+    }
 }
 
+/** Every nav bar item is raised, so it reads as pressable; the current screen's takes the accent colour. */
+@Composable
+private fun navColors(selected: Boolean): GsColors {
+    val s = MaterialTheme.colorScheme
+    return if (selected) GsColors(s.secondaryContainer, s.onSecondaryContainer)
+    else GsColors(s.surfaceContainerHighest, s.onSurface)
+}
+
+/**
+ * Between Apps and whatever's actually open, not with the clock/battery group on the right - a
+ * driver reaches for it right after deciding "not a tap for this", same gesture family as the
+ * two buttons beside it.
+ */
+@Composable
+private fun NavAssistantIcon() {
+    val state by CarAssistant.state.collectAsState()
+    val active = state.phase != CarAssistant.Phase.IDLE
+    GsIconBox({ CarAssistant.start() }, colors = navColors(active), latched = active) {
+        MicGlyph(Modifier.padding(NAV_ITEM_PADDING).size(28.dp))
+    }
+}
+
+/** Inner padding of every icon on the nav bar, leaving each button room inside the 56dp bar. */
+private val NAV_ITEM_PADDING = 8.dp
+
 @Composable
 private fun NavItem(icon: ImageVector, selected: Boolean, onClick: () -> Unit) {
-    val scheme = MaterialTheme.colorScheme
-    Box(
-        Modifier
-            .clip(RoundedCornerShape(18.dp))
-            .background(if (selected) scheme.secondaryContainer else scheme.surfaceContainer)
-            .clickable(onClick = onClick)
-            .padding(12.dp),
-        contentAlignment = Alignment.Center,
-    ) {
-        Icon(icon, contentDescription = null, modifier = Modifier.size(28.dp))
+    GsIconBox(onClick, colors = navColors(selected), latched = selected) {
+        Icon(icon, contentDescription = null, modifier = Modifier.padding(NAV_ITEM_PADDING).size(28.dp))
     }
 }
 
@@ -254,57 +698,213 @@ internal fun rememberNow(): State<Long> = produceState(System.currentTimeMillis(
     }
 }
 
-/** Art, title and play/pause in the nav bar; tapping the art or title opens the full media screen. */
+/** How long the pill shows a new song's title before settling to just the controls. */
+private const val TITLE_SHOWN_MS = 3_000L
+
+/** Below this, the nav bar's middle only has room for the turn, not the player beside it. */
+private val TURN_AND_PLAYER_MIN_WIDTH = 520.dp
+
+/** The next manoeuvre, as the running nav app last described it. */
+private class NextTurn(val icon: CarIcon?, val distance: String, val road: String)
+
+/**
+ * Read straight off the nav app's own template: a navigation app keeps sending its routing card
+ * while it's running, whether or not the map is the screen being shown.
+ */
+@Composable
+private fun rememberNextTurn(): NextTurn? {
+    val status by CarServices.nav.status.collectAsState()
+    val template by CarServices.nav.template.collectAsState()
+    // Read so a change of units redraws the distance straight away, not at the next update.
+    CarSettings.units.collectAsState().value
+    if (status.phase != CarAppConnection.Phase.RUNNING) return null
+    val routing = (template as? NavigationTemplate)?.navigationInfo as? RoutingInfo ?: return null
+    if (routing.isLoading) return null
+    val step = routing.currentStep ?: return null
+    return NextTurn(
+        icon = step.maneuver?.icon,
+        distance = routing.currentDistance.display(),
+        road = step.road.text().ifEmpty { step.cue.text() },
+    )
+}
+
+/** The next turn in the nav bar: arrow, how far, onto what. Tapping goes back to the map. */
+@Composable
+private fun NavTurnPill(turn: NextTurn, onClick: () -> Unit) {
+    // Same finish as every other button on the bar, in the accent colour; the text runs a step
+    // bigger than anything else there, since it's the one thing worth a glance mid-drive.
+    GsIconBox(
+        onClick,
+        Modifier.widthIn(max = 340.dp).height(44.dp),
+        colors = gsColors(GsTone.Primary),
+    ) {
+        Row(
+            Modifier.padding(NAV_ITEM_PADDING),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+        ) {
+            CarGlyph(turn.icon, Modifier.size(28.dp))
+            if (turn.distance.isNotEmpty()) {
+                Text(turn.distance, style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.Bold, maxLines = 1)
+            }
+            if (turn.road.isNotEmpty()) {
+                Text(
+                    turn.road,
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.SemiBold,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
+        }
+    }
+}
+
+/** "Title - Artist" on one line. The text itself cuts it off, and only where the pill runs out of room. */
+private fun nowPlayingLabel(title: String, artist: String): String =
+    listOf(title.trim(), artist.trim()).filter { it.isNotEmpty() }.joinToString(" - ")
+        .ifEmpty { "Nothing playing" }
+
+/**
+ * The player in the nav bar, on every screen. Art and title open the full media screen;
+ * play/pause and skip work right here. The dock button moves the player into the column beside
+ * the map on Home (see [CarHome]), and the pill steps aside there while it's docked - unless the
+ * column is showing lyrics instead, when the pill stays and its dock button swaps them back.
+ */
 @Composable
 private fun NavNowPlaying(navigator: CarNavigator, selected: Boolean, modifier: Modifier = Modifier) {
     val media = CarServices.media
     val phase by media.phase.collectAsState()
     val now by media.now.collectAsState()
     if (phase != CarMedia.Phase.READY || !now.isActive) return
+    // Docked beside the map, the player is already on screen - the pill steps aside for it.
+    if (navigator.sidePanel == SidePanel.CONTROLS && navigator.current == CarScreen.Home) return
+    // The media screen is the full player already; the pill would only repeat its controls.
+    if (navigator.current == CarScreen.Media) return
     val context = LocalContext.current
     val art by produceState(now.art, now.art, now.artUri) { value = now.art ?: MediaArt.load(context, now.artUri) }
-
-    Surface(
-        modifier = modifier,
-        shape = RoundedCornerShape(50),
-        color = if (selected) MaterialTheme.colorScheme.primaryContainer else MaterialTheme.colorScheme.secondaryContainer,
-        contentColor = if (selected) MaterialTheme.colorScheme.onPrimaryContainer else MaterialTheme.colorScheme.onSecondaryContainer,
-    ) {
-    Row(
-        Modifier.padding(start = 6.dp, end = 4.dp, top = 4.dp, bottom = 4.dp),
-        verticalAlignment = Alignment.CenterVertically,
-        horizontalArrangement = Arrangement.spacedBy(6.dp),
-    ) {
-        Row(
-            Modifier
-                .weight(1f, fill = false)
-                .clip(RoundedCornerShape(50))
-                .clickable { navigator.media() },
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(10.dp),
-        ) {
-            Box(Modifier.size(40.dp).clip(RoundedCornerShape(50)).background(MaterialTheme.colorScheme.surfaceVariant)) {
-                art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
-            }
-            Text(
-                now.title.ifEmpty { "Nothing playing" },
-                modifier = Modifier.weight(1f, fill = false),
-                style = MaterialTheme.typography.titleSmall,
-                fontWeight = FontWeight.SemiBold,
-                maxLines = 1,
-                overflow = TextOverflow.Ellipsis,
-            )
-        }
-        FilledIconButton(onClick = media::togglePlay, modifier = Modifier.size(44.dp)) {
-            Icon(
-                if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow,
-                if (now.playing) "Pause" else "Play",
-                Modifier.size(26.dp),
-            )
-        }
-        IconButton(onClick = { media.next() }, modifier = Modifier.size(44.dp)) {
-            Icon(MediaIcons.Next, "Next", Modifier.size(28.dp))
+    val position by produceState(now.currentPosition(), now) {
+        while (true) {
+            value = now.currentPosition()
+            if (!now.playing) break
+            delay(1000)
         }
     }
+
+    // A new song announces itself: title, play/pause and dock for a few seconds, then the title
+    // goes and the pill settles to just the controls - unless the driver keeps the title up.
+    val keepTitle by CarSettings.playerTitle.collectAsState()
+    var announcing by remember { mutableStateOf(true) }
+    LaunchedEffect(now.title, now.artist) {
+        announcing = true
+        delay(TITLE_SHOWN_MS)
+        announcing = false
+    }
+    val showTitle = keepTitle || announcing
+
+    val scheme = MaterialTheme.colorScheme
+    val onPill = if (selected) scheme.onPrimaryContainer else scheme.onSecondaryContainer
+    Surface(
+        modifier = modifier
+            .animateContentSize()
+            // With the title up, all the room the bar has, so as much of it shows as can.
+            .then(if (showTitle) Modifier.fillMaxWidth() else Modifier)
+            .height(44.dp),
+        shape = RoundedCornerShape(14.dp),
+        color = if (selected) scheme.primaryContainer else scheme.secondaryContainer,
+        contentColor = onPill,
+    ) {
+        Box {
+            Row(
+                Modifier.fillMaxHeight().padding(horizontal = 4.dp),
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.spacedBy(6.dp),
+            ) {
+                // Art (and the title while it shows) opens the full media screen.
+                Row(
+                    Modifier
+                        .then(if (showTitle) Modifier.weight(1f) else Modifier)
+                        .fillMaxHeight()
+                        .clip(RoundedCornerShape(10.dp))
+                        .clickable { navigator.media() },
+                    verticalAlignment = Alignment.CenterVertically,
+                    horizontalArrangement = Arrangement.spacedBy(8.dp),
+                ) {
+                    Box(Modifier.size(34.dp).clip(RoundedCornerShape(8.dp)).background(scheme.surfaceVariant)) {
+                        art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
+                    }
+                    if (showTitle) {
+                        Text(
+                            nowPlayingLabel(now.title, now.artist),
+                            style = MaterialTheme.typography.titleSmall,
+                            fontWeight = FontWeight.SemiBold,
+                            maxLines = 1,
+                            overflow = TextOverflow.Ellipsis,
+                        )
+                    }
+                }
+                if (!showTitle) {
+                    GsIconButton(
+                        MediaIcons.Previous, "Previous", media::previous,
+                        enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_PREVIOUS), size = 36.dp, iconSize = 22.dp,
+                    )
+                }
+                GsIconButton(
+                    if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow,
+                    if (now.playing) "Pause" else "Play",
+                    media::togglePlay,
+                    tone = GsTone.Primary, size = 36.dp, iconSize = 22.dp,
+                )
+                if (!showTitle) {
+                    GsIconButton(
+                        MediaIcons.Next, "Next", media::next,
+                        enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_NEXT), size = 36.dp, iconSize = 22.dp,
+                    )
+                }
+                GsIconButton(
+                    MediaIcons.DockRight, "Move the player beside the map", navigator::togglePlayerDock,
+                    size = 36.dp, iconSize = 22.dp,
+                )
+            }
+            if (now.durationMs > 0) {
+                // matchParentSize, so the line follows the pill's width rather than widening it.
+                Box(Modifier.matchParentSize(), contentAlignment = Alignment.BottomStart) {
+                    Box(
+                        Modifier
+                            .fillMaxWidth((position.toFloat() / now.durationMs).coerceIn(0f, 1f))
+                            .height(2.dp)
+                            .background(onPill.copy(alpha = 0.7f)),
+                    )
+                }
+            }
+        }
     }
 }
+
+/**
+ * A filled lightning bolt, next to the battery percentage instead of the word "charging" - the
+ * core Material icon set this project ships (no extended pack, to keep the app small) has no
+ * bolt, so this is drawn rather than a vector asset.
+ */
+@Composable
+private fun ChargingGlyph(modifier: Modifier = Modifier, tint: Color = MaterialTheme.colorScheme.onSurfaceVariant) {
+    androidx.compose.foundation.Canvas(modifier) {
+        val w = size.width
+        val h = size.height
+        val bolt = androidx.compose.ui.graphics.Path().apply {
+            moveTo(w * 0.58f, 0f)
+            lineTo(w * 0.12f, h * 0.58f)
+            lineTo(w * 0.46f, h * 0.58f)
+            lineTo(w * 0.42f, h)
+            lineTo(w * 0.88f, h * 0.40f)
+            lineTo(w * 0.54f, h * 0.40f)
+            close()
+        }
+        drawPath(bolt, tint)
+    }
+}
+
+/** Stands in for the phone's vibration motor on the car screen: does nothing. */
+private object NoHaptics : HapticFeedback {
+    override fun performHapticFeedback(hapticFeedbackType: HapticFeedbackType) {}
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarWhatsNew.kt

@@ -0,0 +1,113 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.produceState
+import kotlinx.coroutines.delay
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.Changelog
+import app.seb3thehacker.gearslip.car.theme.GsButton
+import app.seb3thehacker.gearslip.car.theme.GsSwitch
+import app.seb3thehacker.gearslip.notify.CarMotion
+
+/**
+ * What's new in this build, once, the first time the car screen shows after an update - or any
+ * time from Settings > About. Held back while the car is moving: a list to read is for when
+ * parked. The switch turns the automatic showing off (or back on); it doesn't close the card.
+ */
+@Composable
+fun CarWhatsNew() {
+    val release = Changelog.current ?: return
+    val afterUpdates by CarSettings.whatsNewAfterUpdates.collectAsState()
+    val seen by CarSettings.whatsNewSeen.collectAsState()
+    val open by CarSettings.whatsNewOpen.collectAsState()
+    // Polled: CarMotion is a plain value, and the card should appear once the car stops.
+    val moving by produceState(CarMotion.moving) {
+        while (true) {
+            value = CarMotion.moving
+            delay(5_000)
+        }
+    }
+    val due = afterUpdates && seen < release.versionCode && !moving
+    if (!open && !due) return
+    val close = { CarSettings.closeWhatsNew(release.versionCode) }
+
+    Box(
+        Modifier
+            .fillMaxSize()
+            .background(Color.Black.copy(alpha = 0.5f))
+            .clickable(remember { MutableInteractionSource() }, indication = null, onClick = close),
+        contentAlignment = Alignment.Center,
+    ) {
+        Surface(
+            shape = RoundedCornerShape(24.dp),
+            color = MaterialTheme.colorScheme.surfaceContainerHigh,
+            // Swallows taps on the card itself, so only the scrim around it closes.
+            modifier = Modifier
+                .padding(16.dp)
+                .widthIn(max = 640.dp)
+                .clickable(remember { MutableInteractionSource() }, indication = null) {},
+        ) {
+            Column(Modifier.padding(20.dp), verticalArrangement = Arrangement.spacedBy(14.dp)) {
+                Text(
+                    "What's new in ${release.versionName}",
+                    style = MaterialTheme.typography.headlineSmall,
+                    fontWeight = FontWeight.Bold,
+                )
+                Column(
+                    Modifier.weight(1f, fill = false).verticalScroll(rememberScrollState()),
+                    verticalArrangement = Arrangement.spacedBy(10.dp),
+                ) {
+                    release.changes.forEach { change ->
+                        Row(horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+                            Box(
+                                Modifier
+                                    .padding(top = 9.dp)
+                                    .size(7.dp)
+                                    .background(MaterialTheme.colorScheme.primary, CircleShape),
+                            )
+                            Text(change, style = MaterialTheme.typography.bodyLarge)
+                        }
+                    }
+                }
+                Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(14.dp)) {
+                    GsSwitch(afterUpdates, CarSettings::setWhatsNewAfterUpdates)
+                    Text(
+                        "Show after updates",
+                        style = MaterialTheme.typography.titleMedium,
+                        modifier = Modifier.weight(1f),
+                    )
+                    GsButton(onClick = close, modifier = Modifier.height(56.dp)) {
+                        Text("Got it", style = MaterialTheme.typography.titleMedium)
+                    }
+                }
+            }
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/ClusterNav.kt

@@ -0,0 +1,199 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.car.app.model.CarText
+import androidx.car.app.model.Distance
+import androidx.car.app.navigation.model.Maneuver
+import androidx.car.app.navigation.model.NavigationTemplate
+import androidx.car.app.navigation.model.RoutingInfo
+import androidx.car.app.navigation.model.Step
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.Protobuf
+
+/**
+ * The next turn on the car's instrument cluster, over its NavigationStatusService (Service
+ * field 8), the way Android Auto feeds it:
+ *
+ *   -> NavigationStatus         { status = 1 (1 active, 2 inactive, 3 rerouting) }
+ *   -> NavigationNextTurnEvent  { road = 1; turn_side = 2; event = 3; turn_number = 5; turn_angle = 6 }
+ *   -> NavigationNextTurnDistanceEvent { distance_meters = 1; time_to_turn_seconds = 2;
+ *                                        display_distance_e3 = 3; display_distance_unit = 4 }
+ *
+ * Newer cars also take a NavigationState message; the deprecated pair above is what a 2018
+ * Uconnect understands. The turn comes from the map app's trip (what the Car App Library hands
+ * to clusters), or from its routing card when it sends no trip.
+ */
+class ClusterNav(
+    val channelId: Int,
+    private val sendOnChannel: (messageId: Int, body: ByteArray) -> Unit,
+) {
+    @Volatile private var running = false
+    private var sentStatus = -1
+    private var sentTurn: String? = null
+    private var sentDistance: String? = null
+
+    fun onMessage(messageId: Int, body: ByteArray) {
+        when (messageId) {
+            MSG_CHANNEL_OPEN_RESPONSE -> {
+                val status = Protobuf.readInt32Field(body, 1) ?: 0
+                GearslipLog.i("cluster: <- ChannelOpenResponse: status=$status")
+                if (status == 0) start()
+            }
+            // The car saying when it wants turns. Sending all along is harmless, so these are only logged.
+            MSG_START -> GearslipLog.i("cluster: <- start")
+            MSG_STOP -> GearslipLog.i("cluster: <- stop")
+            else -> GearslipLog.i("cluster: <- unhandled message id=$messageId (${body.size} bytes)")
+        }
+    }
+
+    private fun start() {
+        if (running) return
+        running = true
+        Thread({
+            while (running) {
+                runCatching { tick() }.onFailure { GearslipLog.w("cluster: ${it.message}") }
+                Thread.sleep(TICK_MS)
+            }
+        }, "gearslip-cluster").start()
+    }
+
+    fun stop() {
+        running = false
+    }
+
+    private fun tick() {
+        val turn = NavTurn.current()
+        val status = when {
+            turn == null -> STATUS_INACTIVE
+            turn.rerouting -> STATUS_REROUTING
+            else -> STATUS_ACTIVE
+        }
+        if (status != sentStatus) {
+            sendOnChannel(MSG_STATUS, Protobuf.varintField(1, status.toLong()))
+            GearslipLog.i("cluster: -> ${STATUS_NAMES[status]}")
+            sentStatus = status
+            if (status == STATUS_INACTIVE) { sentTurn = null; sentDistance = null }
+        }
+        if (turn == null || status == STATUS_REROUTING) return
+        sendTurn(turn.step)
+        turn.distance?.let { sendDistance(it, turn.seconds) }
+    }
+
+    private fun sendTurn(step: Step) {
+        val maneuver = step.maneuver
+        val (event, side) = maneuver?.let { eventFor(it.type) } ?: (EVENT_UNKNOWN to SIDE_UNSPECIFIED)
+        val road = step.road.text().ifBlank { step.cue.text() }
+        val key = "$road|$event|$side|${maneuver?.roundaboutExitNumber}"
+        if (key == sentTurn) return
+        sentTurn = key
+        var body = Protobuf.stringField(1, road) +
+            Protobuf.varintField(2, side.toLong()) +
+            Protobuf.varintField(3, event.toLong())
+        maneuver?.roundaboutExitNumber?.takeIf { it > 0 }?.let { body += Protobuf.varintField(5, it.toLong()) }
+        maneuver?.roundaboutExitAngle?.takeIf { it > 0 }?.let { body += Protobuf.varintField(6, it.toLong()) }
+        sendOnChannel(MSG_TURN, body)
+        GearslipLog.i("cluster: -> turn event=$event side=$side road=\"$road\"")
+    }
+
+    /**
+     * The Car App Library's distance units use the same numbers as the protocol's (1 metres ...
+     * 7 yards), so the app's own display choice passes straight through.
+     */
+    private fun sendDistance(distance: Distance, seconds: Long?) {
+        val meters = NavTurn.toMeters(distance)
+        val key = "${distance.displayDistance}|${distance.displayUnit}|${seconds ?: -1}"
+        if (key == sentDistance) return
+        sentDistance = key
+        sendOnChannel(
+            MSG_DISTANCE,
+            Protobuf.varintField(1, meters.toLong()) +
+                Protobuf.varintField(2, (seconds ?: 0L).coerceAtLeast(0)) +
+                Protobuf.varintField(3, (distance.displayDistance * 1000).toLong()) +
+                Protobuf.varintField(4, distance.displayUnit.toLong()),
+        )
+    }
+
+    private fun CarText?.text() = this?.toString().orEmpty()
+
+    companion object {
+        private const val TICK_MS = 500L
+        private const val MSG_CHANNEL_OPEN_RESPONSE = 8
+        private const val MSG_START = 32769
+        private const val MSG_STOP = 32770
+        private const val MSG_STATUS = 32771
+        private const val MSG_TURN = 32772
+        private const val MSG_DISTANCE = 32773
+
+        private const val STATUS_ACTIVE = 1
+        private const val STATUS_INACTIVE = 2
+        private const val STATUS_REROUTING = 3
+        private val STATUS_NAMES = mapOf(1 to "navigating", 2 to "not navigating", 3 to "rerouting")
+
+        private const val SIDE_LEFT = 1
+        private const val SIDE_RIGHT = 2
+        private const val SIDE_UNSPECIFIED = 3
+
+        private const val EVENT_UNKNOWN = 0
+
+        /** The car's turn icon and side for a Car App Library manoeuvre. */
+        fun eventFor(type: Int): Pair<Int, Int> = when (type) {
+            Maneuver.TYPE_DEPART -> 1 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_NAME_CHANGE -> 2 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_KEEP_LEFT, Maneuver.TYPE_TURN_SLIGHT_LEFT -> 3 to SIDE_LEFT
+            Maneuver.TYPE_KEEP_RIGHT, Maneuver.TYPE_TURN_SLIGHT_RIGHT -> 3 to SIDE_RIGHT
+            Maneuver.TYPE_TURN_NORMAL_LEFT -> 4 to SIDE_LEFT
+            Maneuver.TYPE_TURN_NORMAL_RIGHT -> 4 to SIDE_RIGHT
+            Maneuver.TYPE_TURN_SHARP_LEFT -> 5 to SIDE_LEFT
+            Maneuver.TYPE_TURN_SHARP_RIGHT -> 5 to SIDE_RIGHT
+            Maneuver.TYPE_U_TURN_LEFT -> 6 to SIDE_LEFT
+            Maneuver.TYPE_U_TURN_RIGHT -> 6 to SIDE_RIGHT
+            Maneuver.TYPE_ON_RAMP_SLIGHT_LEFT, Maneuver.TYPE_ON_RAMP_NORMAL_LEFT, Maneuver.TYPE_ON_RAMP_SHARP_LEFT,
+            Maneuver.TYPE_ON_RAMP_U_TURN_LEFT -> 7 to SIDE_LEFT
+            Maneuver.TYPE_ON_RAMP_SLIGHT_RIGHT, Maneuver.TYPE_ON_RAMP_NORMAL_RIGHT, Maneuver.TYPE_ON_RAMP_SHARP_RIGHT,
+            Maneuver.TYPE_ON_RAMP_U_TURN_RIGHT -> 7 to SIDE_RIGHT
+            Maneuver.TYPE_OFF_RAMP_SLIGHT_LEFT, Maneuver.TYPE_OFF_RAMP_NORMAL_LEFT -> 8 to SIDE_LEFT
+            Maneuver.TYPE_OFF_RAMP_SLIGHT_RIGHT, Maneuver.TYPE_OFF_RAMP_NORMAL_RIGHT -> 8 to SIDE_RIGHT
+            Maneuver.TYPE_FORK_LEFT -> 9 to SIDE_LEFT
+            Maneuver.TYPE_FORK_RIGHT -> 9 to SIDE_RIGHT
+            Maneuver.TYPE_MERGE_LEFT -> 10 to SIDE_LEFT
+            Maneuver.TYPE_MERGE_RIGHT -> 10 to SIDE_RIGHT
+            Maneuver.TYPE_MERGE_SIDE_UNSPECIFIED -> 10 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_ROUNDABOUT_ENTER_CW, Maneuver.TYPE_ROUNDABOUT_ENTER_CCW -> 11 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_ROUNDABOUT_EXIT_CW, Maneuver.TYPE_ROUNDABOUT_EXIT_CCW -> 12 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_ROUNDABOUT_ENTER_AND_EXIT_CW, Maneuver.TYPE_ROUNDABOUT_ENTER_AND_EXIT_CW_WITH_ANGLE,
+            Maneuver.TYPE_ROUNDABOUT_ENTER_AND_EXIT_CCW, Maneuver.TYPE_ROUNDABOUT_ENTER_AND_EXIT_CCW_WITH_ANGLE -> 13 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_STRAIGHT -> 14 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_FERRY_BOAT, Maneuver.TYPE_FERRY_BOAT_LEFT, Maneuver.TYPE_FERRY_BOAT_RIGHT -> 16 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_FERRY_TRAIN, Maneuver.TYPE_FERRY_TRAIN_LEFT, Maneuver.TYPE_FERRY_TRAIN_RIGHT -> 17 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_DESTINATION, Maneuver.TYPE_DESTINATION_STRAIGHT -> 19 to SIDE_UNSPECIFIED
+            Maneuver.TYPE_DESTINATION_LEFT -> 19 to SIDE_LEFT
+            Maneuver.TYPE_DESTINATION_RIGHT -> 19 to SIDE_RIGHT
+            else -> EVENT_UNKNOWN to SIDE_UNSPECIFIED
+        }
+    }
+}
+
+/** One turn as the car wants it, from whichever source the map app fills. */
+internal class NavTurn(val step: Step, val distance: Distance?, val seconds: Long?, val rerouting: Boolean) {
+    companion object {
+        /** The map app's next turn: from its trip (what clusters get), or its routing card. */
+        fun current(): NavTurn? {
+            val nav = CarServices.navOrNull() ?: return null
+            nav.trip.value?.let { trip ->
+                val step = trip.steps.firstOrNull() ?: return@let
+                val estimate = trip.stepTravelEstimates.firstOrNull()
+                return NavTurn(step, estimate?.remainingDistance, estimate?.remainingTimeSeconds?.takeIf { it >= 0 }, trip.isLoading)
+            }
+            val info = (nav.template.value as? NavigationTemplate)?.navigationInfo as? RoutingInfo ?: return null
+            val step = info.currentStep ?: return null
+            return NavTurn(step, info.currentDistance, null, info.isLoading)
+        }
+
+        fun toMeters(d: Distance): Int = (d.displayDistance * when (d.displayUnit) {
+            Distance.UNIT_KILOMETERS, Distance.UNIT_KILOMETERS_P1 -> 1000.0
+            Distance.UNIT_MILES, Distance.UNIT_MILES_P1 -> 1609.344
+            Distance.UNIT_FEET -> 0.3048
+            Distance.UNIT_YARDS -> 0.9144
+            else -> 1.0
+        }).toInt()
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/DirectionsVoice.kt

@@ -0,0 +1,326 @@
+package app.seb3thehacker.gearslip.car
+
+import android.content.Context
+import android.os.Bundle
+import android.speech.tts.TextToSpeech
+import android.speech.tts.UtteranceProgressListener
+import androidx.car.app.model.CarText
+import androidx.car.app.model.Distance
+import androidx.car.app.navigation.model.Maneuver
+import androidx.car.app.navigation.model.Step
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.audio.AudioLink
+import java.io.File
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.Executors
+import java.util.concurrent.TimeUnit
+import kotlin.math.roundToInt
+
+/**
+ * Spoken turn-by-turn on the car's directions channel (the GUIDANCE audio sink).
+ *
+ * A map app on the phone speaks its own prompts as navigation audio, which Android can't hand to
+ * Gearslip without root, and which the phone mutes while USB audio runs. So Gearslip reads the
+ * same turn the instrument cluster gets ([NavTurn]) and says it itself: once when the turn comes
+ * up, again a kilometre or so out on a long stretch, and once more just before it. The words are
+ * rendered with the phone's text-to-speech to a file, never played on the phone, and streamed to
+ * the car, which ducks the music under them the way it does for real Android Auto.
+ *
+ * Nothing spoken is logged: road names are where the driver is going.
+ */
+object DirectionsVoice {
+
+    private enum class Stage { FAR, PREPARED, DONE }
+
+    private var appContext: Context? = null
+    private var tts: TextToSpeech? = null
+    @Volatile private var ttsReady = false
+    private val pending = ConcurrentHashMap<String, CountDownLatch>()
+
+    @Volatile private var link: AudioLink? = null
+    @Volatile private var running = false
+    private val speaker = Executors.newSingleThreadExecutor { Thread(it, "gearslip-directions").apply { isDaemon = true } }
+    @Volatile private var latest = 0
+
+    private var turnKey: String? = null
+    private var stage = Stage.DONE
+
+    fun init(context: Context) {
+        if (tts != null) return
+        appContext = context.applicationContext
+        tts = TextToSpeech(appContext) { status -> ttsReady = status == TextToSpeech.SUCCESS }.apply {
+            setOnUtteranceProgressListener(object : UtteranceProgressListener() {
+                override fun onStart(utteranceId: String?) {}
+                override fun onDone(utteranceId: String?) { pending.remove(utteranceId)?.countDown() }
+                @Deprecated("Deprecated in Java, no replacement on this API level")
+                override fun onError(utteranceId: String?) { pending.remove(utteranceId)?.countDown() }
+            })
+        }
+    }
+
+    /** The car opened its directions sink: start following the map app's turns. */
+    fun attach(link: AudioLink) {
+        this.link = link
+        GearslipLog.i("guidance: the car offered a directions sink at ${link.sampleRate}Hz x${link.channels}")
+        if (running) return
+        running = true
+        turnKey = null
+        Thread({
+            while (running) {
+                runCatching { tick() }.onFailure { GearslipLog.w("guidance: ${it.message}") }
+                Thread.sleep(TICK_MS)
+            }
+        }, "gearslip-directions-watch").apply { isDaemon = true }.start()
+    }
+
+    fun detach(link: AudioLink) {
+        if (this.link !== link) return
+        this.link = null
+        running = false
+    }
+
+    private fun tick() {
+        if (!CarSettings.speakDirections.value) return
+        val turn = NavTurn.current()
+        if (turn == null) {
+            turnKey = null
+            return
+        }
+        if (turn.rerouting) return
+        val step = turn.step
+        val instruction = instruction(step) ?: return
+        val meters = turn.distance?.let(NavTurn::toMeters)
+        val close = (turn.seconds != null && turn.seconds <= NEAR_SECONDS) || (meters != null && meters <= NEAR_METERS)
+
+        val key = "${step.road.text()}|${step.maneuver?.type}|${step.maneuver?.roundaboutExitNumber}|${step.cue.text()}"
+        if (key != turnKey) {
+            turnKey = key
+            if (step.maneuver?.type == Maneuver.TYPE_DEPART) {
+                stage = Stage.DONE
+                return
+            }
+            if (close || turn.distance == null) {
+                say(instruction)
+                stage = Stage.DONE
+            } else {
+                say("In ${spoken(turn.distance)}, $instruction")
+                stage = if (meters != null && meters > PREPARE_FROM_METERS) Stage.FAR else Stage.PREPARED
+            }
+            return
+        }
+        when {
+            stage != Stage.DONE && close -> {
+                say(instruction)
+                stage = Stage.DONE
+            }
+            stage == Stage.FAR && meters != null && meters <= PREPARE_AT_METERS -> {
+                say("In ${spoken(turn.distance)}, $instruction")
+                stage = Stage.PREPARED
+            }
+        }
+    }
+
+    /** What to do, in words: built from the manoeuvre when the app names one, else the app's own text. */
+    private fun instruction(step: Step): String? {
+        val road = step.road.text()
+        val onto = if (road.isBlank()) "" else " onto $road"
+        val toward = if (road.isBlank()) "" else " toward $road"
+        val maneuver = step.maneuver
+        val built = when (maneuver?.type) {
+            Maneuver.TYPE_TURN_SLIGHT_LEFT -> "Turn slightly left$onto"
+            Maneuver.TYPE_TURN_SLIGHT_RIGHT -> "Turn slightly right$onto"
+            Maneuver.TYPE_TURN_NORMAL_LEFT -> "Turn left$onto"
+            Maneuver.TYPE_TURN_NORMAL_RIGHT -> "Turn right$onto"
+            Maneuver.TYPE_TURN_SHARP_LEFT -> "Turn sharply left$onto"
+            Maneuver.TYPE_TURN_SHARP_RIGHT -> "Turn sharply right$onto"
+            Maneuver.TYPE_U_TURN_LEFT, Maneuver.TYPE_U_TURN_RIGHT -> "Make a U-turn"
+            Maneuver.TYPE_KEEP_LEFT -> "Keep left$toward"
+            Maneuver.TYPE_KEEP_RIGHT -> "Keep right$toward"
+            Maneuver.TYPE_FORK_LEFT -> "Keep left at the fork$toward"
+            Maneuver.TYPE_FORK_RIGHT -> "Keep right at the fork$toward"
+            Maneuver.TYPE_ON_RAMP_SLIGHT_LEFT, Maneuver.TYPE_ON_RAMP_NORMAL_LEFT, Maneuver.TYPE_ON_RAMP_SHARP_LEFT,
+            Maneuver.TYPE_ON_RAMP_U_TURN_LEFT -> "Take the ramp on the left$onto"
+            Maneuver.TYPE_ON_RAMP_SLIGHT_RIGHT, Maneuver.TYPE_ON_RAMP_NORMAL_RIGHT, Maneuver.TYPE_ON_RAMP_SHARP_RIGHT,
+            Maneuver.TYPE_ON_RAMP_U_TURN_RIGHT -> "Take the ramp on the right$onto"
+            Maneuver.TYPE_OFF_RAMP_SLIGHT_LEFT, Maneuver.TYPE_OFF_RAMP_NORMAL_LEFT -> "Take the exit on the left$toward"
+            Maneuver.TYPE_OFF_RAMP_SLIGHT_RIGHT, Maneuver.TYPE_OFF_RAMP_NORMAL_RIGHT -> "Take the exit on the right$toward"
+            Maneuver.TYPE_MERGE_LEFT -> "Merge left$onto"
+            Maneuver.TYPE_MERGE_RIGHT -> "Merge right$onto"
+            Maneuver.TYPE_MERGE_SIDE_UNSPECIFIED -> "Merge$onto"
+            Maneuver.TYPE_ROUNDABOUT_ENTER_AND_EXIT_CW, Maneuver.TYPE_ROUNDABOUT_ENTER_AND_EXIT_CW_WITH_ANGLE,
+            Maneuver.TYPE_ROUNDABOUT_ENTER_AND_EXIT_CCW, Maneuver.TYPE_ROUNDABOUT_ENTER_AND_EXIT_CCW_WITH_ANGLE ->
+                maneuver.roundaboutExitNumber.takeIf { it in 1..ORDINALS.size }
+                    ?.let { "At the roundabout, take the ${ORDINALS[it - 1]} exit$onto" }
+                    ?: "Go through the roundabout$onto"
+            Maneuver.TYPE_ROUNDABOUT_ENTER_CW, Maneuver.TYPE_ROUNDABOUT_ENTER_CCW -> "Enter the roundabout"
+            Maneuver.TYPE_ROUNDABOUT_EXIT_CW, Maneuver.TYPE_ROUNDABOUT_EXIT_CCW -> "Exit the roundabout$onto"
+            Maneuver.TYPE_STRAIGHT -> "Continue straight$onto"
+            Maneuver.TYPE_NAME_CHANGE -> "Continue$onto"
+            Maneuver.TYPE_FERRY_BOAT, Maneuver.TYPE_FERRY_BOAT_LEFT, Maneuver.TYPE_FERRY_BOAT_RIGHT -> "Take the ferry"
+            Maneuver.TYPE_FERRY_TRAIN, Maneuver.TYPE_FERRY_TRAIN_LEFT, Maneuver.TYPE_FERRY_TRAIN_RIGHT -> "Take the train"
+            Maneuver.TYPE_DESTINATION, Maneuver.TYPE_DESTINATION_STRAIGHT -> "Your destination is ahead"
+            Maneuver.TYPE_DESTINATION_LEFT -> "Your destination is on the left"
+            Maneuver.TYPE_DESTINATION_RIGHT -> "Your destination is on the right"
+            else -> null
+        }
+        return built ?: step.cue.text().ifBlank { null }
+    }
+
+    /** The app's own rounded distance, read the way a person would say it. */
+    private fun spoken(d: Distance): String {
+        val n = d.displayDistance
+        val number = if (n % 1.0 == 0.0) n.toInt().toString() else "%.1f".format(n)
+        val one = n == 1.0
+        return when (d.displayUnit) {
+            Distance.UNIT_KILOMETERS, Distance.UNIT_KILOMETERS_P1 -> if (one) "1 kilometer" else "$number kilometers"
+            Distance.UNIT_MILES, Distance.UNIT_MILES_P1 -> when (n) {
+                0.25 -> "a quarter mile"
+                0.5 -> "half a mile"
+                0.75 -> "three quarters of a mile"
+                1.0 -> "1 mile"
+                else -> "$number miles"
+            }
+            Distance.UNIT_FEET -> "$number feet"
+            Distance.UNIT_YARDS -> "$number yards"
+            else -> "${n.roundToInt()} meters"
+        }
+    }
+
+    /** Newest wins: a prompt still waiting when the next one arrives is already out of date. */
+    private fun say(text: String) {
+        val id = ++latest
+        speaker.execute {
+            if (id != latest) return@execute
+            runCatching { play(text, id) }.onFailure { GearslipLog.w("guidance: could not speak a turn: ${it.message}") }
+        }
+    }
+
+    private fun play(text: String, id: Int) {
+        val engine = tts ?: return
+        val context = appContext ?: return
+        val sink = link ?: return
+        if (!ttsReady) {
+            GearslipLog.w("guidance: text-to-speech isn't ready, a turn went unspoken")
+            return
+        }
+        val file = File(context.cacheDir, "directions.wav")
+        val utterance = "gearslip-directions-$id"
+        val done = CountDownLatch(1)
+        pending[utterance] = done
+        if (engine.synthesizeToFile(text, Bundle(), file, utterance) != TextToSpeech.SUCCESS) {
+            pending.remove(utterance)
+            return
+        }
+        if (!done.await(SYNTH_TIMEOUT_S, TimeUnit.SECONDS)) {
+            pending.remove(utterance)
+            GearslipLog.w("guidance: text-to-speech took too long, a turn went unspoken")
+            return
+        }
+        val pcm = Wav.read(file)?.let { Wav.convert(it, sink.sampleRate, sink.channels) } ?: run {
+            GearslipLog.w("guidance: text-to-speech gave audio Gearslip can't read")
+            return
+        }
+        stream(sink, pcm)
+        GearslipLog.i("guidance: spoke a turn (${pcm.size / (2 * sink.channels) * 1000 / sink.sampleRate} ms)")
+    }
+
+    /** Start, the words in 20 ms chunks at about real time, a little silence, Stop. */
+    private fun stream(sink: AudioLink, pcm: ByteArray) {
+        val frame = 2 * sink.channels
+        val chunk = sink.sampleRate / 50 * frame
+        val chunkMs = 20L
+        val padded = pcm + ByteArray(sink.sampleRate / 5 * frame) // 200 ms tail so the last word isn't clipped
+        sink.start()
+        try {
+            val began = System.currentTimeMillis()
+            var offset = 0
+            var sent = 0
+            while (offset < padded.size && link === sink) {
+                val size = minOf(chunk, padded.size - offset)
+                sink.write(padded.copyOfRange(offset, offset + size), size)
+                offset += size
+                sent++
+                val ahead = sent * chunkMs - (System.currentTimeMillis() - began)
+                if (ahead > LEAD_MS) Thread.sleep(ahead - LEAD_MS)
+            }
+            // Let the car play what it has before closing the stream on it.
+            Thread.sleep(LEAD_MS)
+        } finally {
+            sink.stop()
+        }
+    }
+
+    private fun CarText?.text() = this?.toString().orEmpty()
+
+    /** 16-bit PCM from the WAV text-to-speech writes, reshaped for the car's sink. */
+    private object Wav {
+        class Pcm(val samples: ShortArray, val rate: Int, val channels: Int)
+
+        fun read(file: File): Pcm? {
+            val bytes = file.readBytes()
+            if (bytes.size < 12 || String(bytes, 0, 4) != "RIFF" || String(bytes, 8, 4) != "WAVE") return null
+            val buf = ByteBuffer.wrap(bytes).order(ByteOrder.LITTLE_ENDIAN)
+            var pos = 12
+            var rate = 0
+            var channels = 0
+            var bits = 0
+            while (pos + 8 <= bytes.size) {
+                val name = String(bytes, pos, 4)
+                val size = buf.getInt(pos + 4)
+                val body = pos + 8
+                // Some engines write a streaming WAV with a zero or oversized data length.
+                val end = if (size <= 0 || body + size > bytes.size) bytes.size else body + size
+                when (name) {
+                    "fmt " -> {
+                        channels = buf.getShort(body + 2).toInt()
+                        rate = buf.getInt(body + 4)
+                        bits = buf.getShort(body + 14).toInt()
+                    }
+                    "data" -> {
+                        if (bits != 16 || rate <= 0 || channels <= 0) return null
+                        val samples = ShortArray((end - body) / 2)
+                        buf.position(body)
+                        buf.asShortBuffer().get(samples, 0, samples.size)
+                        return Pcm(samples, rate, channels)
+                    }
+                }
+                pos = end + (end and 1)
+            }
+            return null
+        }
+
+        /** Mixes to mono, resamples linearly, then copies to each of the car's channels. */
+        fun convert(pcm: Pcm, rate: Int, channels: Int): ByteArray {
+            val frames = pcm.samples.size / pcm.channels
+            val mono = FloatArray(frames) { f ->
+                var sum = 0f
+                for (c in 0 until pcm.channels) sum += pcm.samples[f * pcm.channels + c]
+                sum / pcm.channels
+            }
+            val outFrames = (frames.toLong() * rate / pcm.rate).toInt()
+            val out = ByteBuffer.allocate(outFrames * channels * 2).order(ByteOrder.LITTLE_ENDIAN)
+            val step = pcm.rate.toDouble() / rate
+            for (i in 0 until outFrames) {
+                val at = i * step
+                val j = at.toInt().coerceAtMost(frames - 1)
+                val next = (j + 1).coerceAtMost(frames - 1)
+                val v = mono[j] + (mono[next] - mono[j]) * (at - j).toFloat()
+                val s = v.roundToInt().coerceIn(Short.MIN_VALUE.toInt(), Short.MAX_VALUE.toInt()).toShort()
+                repeat(channels) { out.putShort(s) }
+            }
+            return out.array()
+        }
+    }
+
+    private const val TICK_MS = 500L
+    private const val NEAR_SECONDS = 12L
+    private const val NEAR_METERS = 120
+    private const val PREPARE_FROM_METERS = 2_500
+    private const val PREPARE_AT_METERS = 1_000
+    private const val LEAD_MS = 100L
+    private const val SYNTH_TIMEOUT_S = 10L
+    private val ORDINALS = listOf("first", "second", "third", "fourth", "fifth", "sixth", "seventh", "eighth")
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/FocusRing.kt

@@ -0,0 +1,84 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.IndicationNodeFactory
+import androidx.compose.foundation.interaction.FocusInteraction
+import androidx.compose.foundation.interaction.InteractionSource
+import androidx.compose.material3.ripple
+import androidx.compose.ui.geometry.CornerRadius
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.ContentDrawScope
+import androidx.compose.ui.graphics.drawscope.Stroke
+import androidx.compose.ui.node.DelegatableNode
+import androidx.compose.ui.node.DelegatingNode
+import androidx.compose.ui.node.DrawModifierNode
+import androidx.compose.ui.node.invalidateDraw
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.launch
+
+/**
+ * What every car button shows: the usual ripple when pressed, and a ring in the accent color
+ * while the knob or D-pad is on it. Cars without a knob never see the ring, since nothing takes
+ * focus while the screen is in touch mode.
+ *
+ * It replaces the theme's ripple (LocalIndication) for the whole car UI, so any `clickable` that
+ * doesn't pass its own indication gets the ring for free.
+ */
+internal class FocusRingIndication(private val color: Color) : IndicationNodeFactory {
+    private val ripple = ripple()
+
+    override fun create(interactionSource: InteractionSource): DelegatableNode =
+        FocusRingNode(ripple.create(interactionSource), interactionSource, color)
+
+    override fun equals(other: Any?) = other is FocusRingIndication && other.color == color
+    override fun hashCode() = color.hashCode()
+}
+
+private class FocusRingNode(
+    rippleNode: DelegatableNode,
+    private val source: InteractionSource,
+    private val color: Color,
+) : DelegatingNode(), DrawModifierNode {
+    private var focused = false
+
+    init { delegate(rippleNode) }
+
+    override fun onAttach() {
+        coroutineScope.launch {
+            var holding = 0
+            source.interactions.collect {
+                when (it) {
+                    is FocusInteraction.Focus -> holding++
+                    is FocusInteraction.Unfocus -> holding--
+                }
+                val now = holding > 0
+                if (now != focused) {
+                    focused = now
+                    invalidateDraw()
+                }
+            }
+        }
+    }
+
+    override fun ContentDrawScope.draw() {
+        drawContent()
+        if (!focused) return
+        // Inside the button's bounds, since most buttons clip to their shape: drawn outside, a
+        // rounded tile would cut its own ring off.
+        val width = RING_WIDTH.toPx()
+        val radius = minOf(CORNER.toPx(), size.minDimension / 2)
+        drawRoundRect(
+            color,
+            topLeft = Offset(width / 2, width / 2),
+            size = Size(size.width - width, size.height - width),
+            cornerRadius = CornerRadius(radius),
+            style = Stroke(width),
+        )
+    }
+
+    private companion object {
+        val RING_WIDTH = 3.dp
+        val CORNER = 16.dp
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/LocationCheck.kt

@@ -0,0 +1,93 @@
+package app.seb3thehacker.gearslip.car
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.location.LocationManager
+import android.os.Handler
+import android.os.Looper
+import app.seb3thehacker.gearslip.GearslipLog
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * Map apps can't find the car with the phone's location turned off. Ten seconds after the car
+ * shows Gearslip, this checks, and the car says so until location comes on or the drive ends.
+ */
+object LocationCheck {
+
+    private val _off = MutableStateFlow(false)
+    /** True while the phone's location is turned off during a drive. */
+    val off: StateFlow<Boolean> = _off
+
+    private val _carDismissed = MutableStateFlow(false)
+    /** The driver tapped OK on the car's card; it stays away for the rest of this drive. */
+    val carDismissed: StateFlow<Boolean> = _carDismissed
+
+    private val log = GearslipLog.tagged("location")
+    private val main = Handler(Looper.getMainLooper())
+    private var appContext: Context? = null
+    private var armed = false
+    private var receiver: BroadcastReceiver? = null
+
+    fun init(context: Context) {
+        appContext = context.applicationContext
+    }
+
+    /** The car shows Gearslip. Called again whenever the video restarts, so it arms once per drive. */
+    fun onProjecting() = main.post {
+        if (armed) return@post
+        armed = true
+        main.postDelayed(::start, WAIT_MS)
+    }
+
+    fun onCarDisconnected() = main.post {
+        armed = false
+        main.removeCallbacksAndMessages(null)
+        stopWatching()
+        _off.value = false
+        _carDismissed.value = false
+    }
+
+    fun dismissOnCar() {
+        _carDismissed.value = true
+    }
+
+    /** "Don't show again" on the car: turns the warning off in Settings, for every car. */
+    fun neverAgain() {
+        CarSettings.setLocationWarning(false)
+        log.i("location warning turned off")
+        _carDismissed.value = true
+        _off.value = false
+    }
+
+    private fun start() {
+        if (!armed) return
+        check()
+        // Turning location on clears the warning, and turning it off again brings it back.
+        val context = appContext ?: return
+        val r = object : BroadcastReceiver() {
+            override fun onReceive(context: Context, intent: Intent) = check()
+        }
+        context.registerReceiver(r, IntentFilter(LocationManager.MODE_CHANGED_ACTION), Context.RECEIVER_EXPORTED)
+        receiver = r
+    }
+
+    private fun check() {
+        if (!armed) return
+        val manager = appContext?.getSystemService(LocationManager::class.java) ?: return
+        val off = CarSettings.locationWarning.value && !manager.isLocationEnabled
+        if (_off.value == off) return
+        _off.value = off
+        log.i(if (off) "the phone's location is off" else "the phone's location is on")
+    }
+
+    private fun stopWatching() {
+        val r = receiver ?: return
+        receiver = null
+        runCatching { appContext?.unregisterReceiver(r) }
+    }
+
+    private const val WAIT_MS = 10_000L
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/MediaScreen.kt

@@ -1,11 +1,17 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
 import androidx.compose.foundation.layout.Arrangement
 import android.provider.Settings
 import android.content.Intent
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -24,15 +30,14 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
 import androidx.compose.material.icons.filled.ArrowBack
 import androidx.compose.material.icons.filled.PlayArrow
-import androidx.compose.material3.Button
-import androidx.compose.material3.FilledIconButton
+import androidx.compose.material.icons.filled.Search
 import androidx.compose.material3.Icon
-import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
@@ -44,7 +49,9 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.PathFillType
 import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.foundation.layout.widthIn
 import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.graphics.vector.addPathNodes
@@ -54,7 +61,6 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
-import app.seb3thehacker.gearslip.audio.CarAudio
 import app.seb3thehacker.gearslip.media.CarMedia
 import app.seb3thehacker.gearslip.media.MediaApp
 import app.seb3thehacker.gearslip.media.MediaArt
@@ -62,7 +68,11 @@ import app.seb3thehacker.gearslip.media.LyricsResult
 import app.seb3thehacker.gearslip.media.Lyrics
 import app.seb3thehacker.gearslip.media.MediaEntry
 import app.seb3thehacker.gearslip.media.NowPlaying
+import app.seb3thehacker.gearslip.media.QueueTrack
 import android.media.session.PlaybackState
+import kotlinx.coroutines.delay
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.PaddingValues
 
 /**
  * A media app on the car screen: what it is playing and its controls on the left, the tree it
@@ -74,62 +84,118 @@ fun MediaScreen(app: MediaApp, onExit: () -> Unit) {
     val media = CarServices.media
     val phase by media.phase.collectAsStateWithLifecycle()
     val now by media.now.collectAsStateWithLifecycle()
+    val queue by media.queue.collectAsStateWithLifecycle()
     val browse by media.browse.collectAsStateWithLifecycle()
     val rejection by media.rejection.collectAsStateWithLifecycle()
-    val capture by CarAudio.capture.collectAsStateWithLifecycle()
-    val navigator = LocalCarNavigator.current
-    var tab by remember {
-        mutableStateOf(if (navigator.lyricsRequested) Tab.LYRICS else Tab.BROWSE).also { navigator.lyricsRequested = false }
-    }
+    val search by media.search.collectAsStateWithLifecycle()
+    var tab by remember { mutableStateOf(Tab.NOW_PLAYING) }
+    var searching by remember { mutableStateOf(false) }
 
     // The connection outlives this screen: the home screen's player is the same one.
     LaunchedEffect(app) { CarServices.openMedia(app) }
 
-    Column(Modifier.fillMaxSize().padding(horizontal = 16.dp, vertical = 10.dp)) {
-        Row(verticalAlignment = Alignment.CenterVertically) {
-            IconButton(onClick = onExit) { Icon(Icons.Filled.ArrowBack, contentDescription = "Back to apps") }
-            Text(app.label, style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.SemiBold)
-            Spacer(Modifier.weight(1f))
-            AudioBadge(capture)
+    val art = rememberArt(now)
+
+    // The art's colour behind everything, header included; the buttons keep their own.
+    Surface(Modifier.fillMaxSize(), color = rememberArtColor(art, MaterialTheme.colorScheme.background, darkLightness = 0.15f, lightLightness = 0.9f)) {
+        if (phase != CarMedia.Phase.READY) {
+            Column(Modifier.fillMaxSize()) {
+                AppIdentity(app, onExit, Modifier.padding(horizontal = 16.dp, vertical = 10.dp))
+                when (phase) {
+                    CarMedia.Phase.REJECTED -> when (rejection) {
+                        CarMedia.Rejection.NEEDS_NOTIFICATION_ACCESS -> Notice(
+                            "${app.label} keeps its library to itself.",
+                            "Gearslip can still control it once it has Notification access on the phone. " +
+                                "Allow it under Settings > Notifications > Notification access.",
+                            action = "Open on phone" to {
+                                val app = context.applicationContext
+                                runCatching {
+                                    app.startActivity(
+                                        Intent(Settings.ACTION_NOTIFICATION_LISTENER_SETTINGS).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
+                                    )
+                                }
+                            },
+                        )
+                        CarMedia.Rejection.NEEDS_APP_RUNNING -> Notice(
+                            "${app.label} isn't running.",
+                            "${app.label} plays through Gearslip's own player, but only while it's " +
+                                "open on the phone. Open it once and it keeps playing here in the car.",
+                            action = "Open ${app.label}" to { media.launchAndConnect(app) },
+                        )
+                        CarMedia.Rejection.REFUSED -> Notice(
+                            "${app.label} would not let Gearslip browse it.",
+                            "Some media apps only accept Google's own host.",
+                        )
+                    }
+                    else -> Notice("Connecting to ${app.label}…", null)
+                }
+            }
+            return@Surface
         }
 
-        when (phase) {
-            CarMedia.Phase.REJECTED -> when (rejection) {
-                CarMedia.Rejection.NEEDS_NOTIFICATION_ACCESS -> Notice(
-                    "${app.label} keeps its library to itself.",
-                    "Gearslip can still control it once it has Notification access on the phone. " +
-                        "Allow it under Settings > Notifications > Notification access.",
-                    action = "Open on phone" to {
-                        val app = context.applicationContext
-                        runCatching {
-                            app.startActivity(
-                                Intent(Settings.ACTION_NOTIFICATION_LISTENER_SETTINGS).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
-                            )
-                        }
-                    },
-                )
-                CarMedia.Rejection.REFUSED -> Notice(
-                    "${app.label} would not let Gearslip browse it.",
-                    "Some media apps only accept Google's own host.",
-                )
+        if (searching) {
+            SearchPanel(
+                appLabel = app.label,
+                media = media,
+                canPickForYou = now.canSearch,
+                onPlayed = {
+                    searching = false
+                    tab = Tab.NOW_PLAYING
+                },
+                onOpened = {
+                    searching = false
+                    tab = Tab.BROWSE
+                },
+                onPickForYou = { query ->
+                    media.search(query)
+                    searching = false
+                    tab = Tab.NOW_PLAYING
+                },
+                onClose = { searching = false },
+            )
+            return@Surface
+        }
+
+        // Two columns, split the same way on every tab so nothing jumps when switching: the app
+        // and the art (or, beside a list, the compact player) on the left; the tabs across the
+        // top of the right column, over whatever the tab shows.
+        Row(
+            Modifier.fillMaxSize().padding(start = 16.dp, end = 16.dp, top = 10.dp, bottom = 8.dp),
+            horizontalArrangement = Arrangement.spacedBy(24.dp),
+        ) {
+            Column(Modifier.weight(0.8f).fillMaxHeight()) {
+                AppIdentity(app, onExit)
+                Spacer(Modifier.height(12.dp))
+                if (tab == Tab.NOW_PLAYING) {
+                    CoverArt(art, Modifier.weight(1f).fillMaxWidth())
+                } else {
+                    CompactPlayer(now, media, Modifier.weight(1f).fillMaxWidth())
+                }
             }
-            CarMedia.Phase.CONNECTING, CarMedia.Phase.IDLE -> Notice("Connecting to ${app.label}…", null)
-            CarMedia.Phase.READY -> Row(
-                Modifier.fillMaxSize().padding(top = 6.dp),
-                horizontalArrangement = Arrangement.spacedBy(16.dp),
-            ) {
-                NowPlayingPanel(now, media, Modifier.width(250.dp).fillMaxHeight())
-                Column(Modifier.weight(1f).fillMaxHeight()) {
-                    Row {
-                        TextButton(onClick = { tab = Tab.BROWSE }) {
-                            Text("Browse", fontWeight = if (tab == Tab.BROWSE) FontWeight.Bold else FontWeight.Normal)
-                        }
-                        TextButton(onClick = { tab = Tab.LYRICS }) {
-                            Text("Lyrics", fontWeight = if (tab == Tab.LYRICS) FontWeight.Bold else FontWeight.Normal)
-                        }
+            Column(Modifier.weight(1.2f).fillMaxHeight()) {
+                Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                    MediaTab("Now playing", tab == Tab.NOW_PLAYING, Modifier.weight(1f)) { tab = Tab.NOW_PLAYING }
+                    MediaTab("Browse", tab == Tab.BROWSE, Modifier.weight(1f)) { tab = Tab.BROWSE }
+                    MediaTab("Up next", tab == Tab.QUEUE, Modifier.weight(1f)) { tab = Tab.QUEUE }
+                    MediaTab("Lyrics", tab == Tab.LYRICS, Modifier.weight(1f)) { tab = Tab.LYRICS }
+                    if (now.canSearch || media.canSearchLibrary) {
+                        GsIconButton(
+                            Icons.Filled.Search,
+                            "Search ${app.label}",
+                            { searching = true },
+                            colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHigh, MaterialTheme.colorScheme.onSurface),
+                            size = 44.dp,
+                            shape = MaterialTheme.shapes.large,
+                        )
                     }
+                }
+                search?.let { SearchStatus(it, app.label, media::dismissSearch) }
+                Spacer(Modifier.height(12.dp))
+                Box(Modifier.weight(1f).fillMaxWidth()) {
                     when (tab) {
+                        Tab.NOW_PLAYING -> NowPlayingControls(now, media, Modifier.fillMaxSize())
                         Tab.BROWSE -> BrowsePanel(browse, media, app.label, Modifier.fillMaxSize())
+                        Tab.QUEUE -> QueuePanel(queue, now, media, Modifier.fillMaxSize())
                         Tab.LYRICS -> LyricsPanel(now, Modifier.fillMaxSize())
                     }
                 }
@@ -138,17 +204,196 @@ fun MediaScreen(app: MediaApp, onExit: () -> Unit) {
     }
 }
 
-private enum class Tab { BROWSE, LYRICS }
+/**
+ * Back, then which app this is: its own icon and its name, quieter than the song title - the
+ * name alone in big bold type read as one more heading fighting the track for attention.
+ */
+@Composable
+private fun AppIdentity(app: MediaApp, onExit: () -> Unit, modifier: Modifier = Modifier) {
+    val icon = remember(app) { findEntry(app.component.flattenToString())?.icon }
+    Row(modifier, verticalAlignment = Alignment.CenterVertically) {
+        GsIconButton(Icons.Filled.ArrowBack, "Back", onExit, size = 44.dp)
+        Spacer(Modifier.width(14.dp))
+        icon?.let {
+            Image(it, null, Modifier.size(26.dp).clip(RoundedCornerShape(7.dp)))
+            Spacer(Modifier.width(10.dp))
+        }
+        Text(
+            app.label.lowercase().replaceFirstChar { it.titlecase() },
+            style = MaterialTheme.typography.titleMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+        )
+    }
+}
+
+private enum class Tab { NOW_PLAYING, BROWSE, QUEUE, LYRICS }
+
+// --- search ----------------------------------------------------------------------------------
+
+/**
+ * Types a search for the app to play. The app picks the result and plays it, the way it would
+ * for "play X" from a voice assistant, so there's no list to choose from.
+ */
+/**
+ * Search inside the media app. It asks the app's library for matches half a second after the
+ * driver stops typing and lists them, so the driver picks exactly what plays: a song plays, an
+ * album or artist opens in Browse. The search key hides the keyboard to show more results; the
+ * field brings it back. An app with no library search can still be told to play its own best
+ * match, which is all the panel could do before.
+ */
+@Composable
+private fun SearchPanel(
+    appLabel: String,
+    media: CarMedia,
+    canPickForYou: Boolean,
+    onPlayed: () -> Unit,
+    onOpened: () -> Unit,
+    onPickForYou: (String) -> Unit,
+    onClose: () -> Unit,
+) {
+    var query by remember { mutableStateOf("") }
+    var typing by remember { mutableStateOf(true) }
+    val results by media.results.collectAsStateWithLifecycle()
+    LaunchedEffect(query) {
+        delay(SEARCH_PAUSE_MS)
+        media.searchLibrary(query)
+    }
+    DisposableEffect(Unit) { onDispose { media.clearResults() } }
+
+    val trimmed = query.trim()
+    val current = results?.takeIf { it.query == trimmed }
+    val unsupported = current?.supported == false
+
+    Column(Modifier.fillMaxSize()) {
+        Row(
+            Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 10.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+        ) {
+            GsIconButton(Icons.Filled.ArrowBack, "Back", onClose, size = ICON_BUTTON_SIZE)
+            SearchField(
+                query,
+                "Search $appLabel",
+                Modifier.weight(1f).clickable { typing = true },
+                onClear = {
+                    query = ""
+                    typing = true
+                },
+            )
+        }
+        Box(Modifier.weight(1f).fillMaxWidth().padding(horizontal = 16.dp)) {
+            val entries = current?.entries
+            when {
+                trimmed.isEmpty() -> SearchNote("Type a song, artist, album, or playlist.")
+                unsupported && canPickForYou ->
+                    SearchNote("$appLabel can't list results. Press search, and $appLabel picks what to play.")
+                unsupported -> SearchNote("$appLabel can't search from the car.")
+                entries == null -> SearchNote("Searching $appLabel…")
+                entries.isEmpty() -> SearchNote("$appLabel found nothing for \"$trimmed\".")
+                else -> LazyColumn(verticalArrangement = Arrangement.spacedBy(8.dp), contentPadding = PaddingValues(bottom = 8.dp)) {
+                    items(entries) { entry ->
+                        EntryRow(entry, media) {
+                            if (entry.browsable) {
+                                media.select(entry)
+                                onOpened()
+                            } else {
+                                media.playAll(entry)
+                                onPlayed()
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        if (typing) {
+            CarKeyboard(
+                text = query,
+                onTextChange = { query = it },
+                onSubmit = {
+                    when {
+                        trimmed.isEmpty() -> Unit
+                        unsupported && canPickForYou -> onPickForYou(trimmed)
+                        else -> typing = false
+                    }
+                },
+                onDismiss = { if (trimmed.isEmpty()) onClose() else typing = false },
+            )
+        }
+    }
+}
+
+@Composable
+private fun SearchNote(text: String) {
+    Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+        Text(
+            text,
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            textAlign = androidx.compose.ui.text.style.TextAlign.Center,
+        )
+    }
+}
+
+/** How long typing has to pause before the library is searched. */
+private const val SEARCH_PAUSE_MS = 1_000L
+
+/** A line under the tabs while the app works on a search, and if it plays nothing for it. */
+@Composable
+private fun SearchStatus(search: CarMedia.Search, appLabel: String, onDismiss: () -> Unit) {
+    Surface(
+        onClick = onDismiss,
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
+    ) {
+        Text(
+            if (search.ignored) "$appLabel didn't play anything for \"${search.query}\"."
+            else "Searching $appLabel for \"${search.query}\"…",
+            style = MaterialTheme.typography.bodyLarge,
+            maxLines = 2,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 10.dp),
+        )
+    }
+}
+
+/** A bigger, easier-to-hit tab than a plain [TextButton] - this row is the only navigation on the screen. */
+@Composable
+private fun MediaTab(label: String, selected: Boolean, modifier: Modifier, onClick: () -> Unit) {
+    GsIconBox(
+        onClick = onClick,
+        modifier = modifier.height(44.dp),
+        colors = if (selected) GsColors(MaterialTheme.colorScheme.primaryContainer, MaterialTheme.colorScheme.onPrimaryContainer)
+        else GsColors(MaterialTheme.colorScheme.surfaceContainerHigh, MaterialTheme.colorScheme.onSurface),
+        shape = MaterialTheme.shapes.large,
+        latched = selected,
+    ) {
+        Text(
+            label,
+            style = MaterialTheme.typography.titleSmall,
+            fontWeight = if (selected) FontWeight.Bold else FontWeight.Normal,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+        )
+    }
+}
 
 /**
  * The song's lyrics, fetched when this tab opens. Synced lyrics follow the playback position with
  * the current line in the accent colour; unsynced ones are plain scrolling text.
  */
 @Composable
-private fun LyricsPanel(now: NowPlaying, modifier: Modifier) {
+internal fun LyricsPanel(
+    now: NowPlaying,
+    modifier: Modifier,
+    lineStyle: androidx.compose.ui.text.TextStyle = MaterialTheme.typography.titleLarge,
+) {
+    val context = LocalContext.current
     val lyrics by produceState<LyricsState>(LyricsState.Loading, now.title, now.artist, now.album, now.durationMs) {
         value = LyricsState.Loading
-        value = Lyrics.find(now.title, now.artist, now.album, now.durationMs)
+        value = Lyrics.find(context, now.title, now.artist, now.album, now.durationMs)
             ?.let { LyricsState.Found(it) } ?: LyricsState.Missing
     }
     val list = rememberLazyListState()
@@ -178,7 +423,7 @@ private fun LyricsPanel(now: NowPlaying, modifier: Modifier) {
                 itemsIndexed(lines) { index, line ->
                     Text(
                         line.text.ifEmpty { " " },
-                        style = MaterialTheme.typography.titleLarge,
+                        style = lineStyle,
                         fontWeight = if (index == current) FontWeight.Bold else FontWeight.Normal,
                         color = when {
                             !state.result.synced -> MaterialTheme.colorScheme.onSurface
@@ -198,17 +443,6 @@ private sealed interface LyricsState {
     class Found(val result: LyricsResult) : LyricsState
 }
 
-@Composable
-private fun AudioBadge(capture: CarAudio.Capture) {
-    val text = when (capture) {
-        CarAudio.Capture.ON -> "Audio to car"
-        CarAudio.Capture.ASKING -> "Allow audio capture on the phone"
-        CarAudio.Capture.DENIED -> "Audio stays on the phone"
-        CarAudio.Capture.OFF -> return
-    }
-    Text(text, style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.onSurfaceVariant)
-}
-
 @Composable
 private fun Notice(title: String, detail: String?, action: Pair<String, () -> Unit>? = null) {
     Column(
@@ -225,80 +459,97 @@ private fun Notice(title: String, detail: String?, action: Pair<String, () -> Un
         }
         action?.let { (label, run) ->
             Spacer(Modifier.height(12.dp))
-            androidx.compose.material3.FilledTonalButton(onClick = run) { Text(label) }
+            GsButton(onClick = run, tone = GsTone.Tonal) { Text(label) }
         }
     }
 }
 
 // --- now playing -----------------------------------------------------------------------------
 
+/**
+ * The now-playing view on its own, for places with no tabs around it (an app's own
+ * now-playing template): the cover on the left, [NowPlayingControls] on the right.
+ */
 @Composable
-private fun NowPlayingPanel(now: NowPlaying, media: CarMedia, modifier: Modifier) {
-    val context = LocalContext.current
-    val art by produceState(now.art, now.art, now.artUri) {
-        value = now.art ?: MediaArt.load(context, now.artUri)
-    }
-    var position by remember { mutableLongStateOf(0L) }
-    LaunchedEffect(now) {
-        while (true) {
-            position = now.currentPosition()
-            kotlinx.coroutines.delay(500)
-        }
+internal fun NowPlayingPage(now: NowPlaying, media: CarMedia, modifier: Modifier) {
+    Row(
+        modifier.padding(horizontal = 24.dp, vertical = 8.dp),
+        horizontalArrangement = Arrangement.spacedBy(24.dp),
+    ) {
+        CoverArt(rememberArt(now), Modifier.weight(0.8f).fillMaxHeight())
+        NowPlayingControls(now, media, Modifier.weight(1.2f).fillMaxHeight())
     }
+}
 
-    Column(modifier, horizontalAlignment = Alignment.CenterHorizontally) {
+/** The cover, as big a square as its space allows, centred in it. */
+@Composable
+private fun CoverArt(art: android.graphics.Bitmap?, modifier: Modifier) {
+    BoxWithConstraints(modifier, contentAlignment = Alignment.Center) {
         Surface(
             shape = MaterialTheme.shapes.large,
             color = MaterialTheme.colorScheme.surfaceVariant,
-            modifier = Modifier.size(170.dp),
+            shadowElevation = 6.dp,
+            modifier = Modifier.size(minOf(maxWidth, maxHeight)),
         ) {
-            art?.let {
-                Image(it.asImageBitmap(), null, Modifier.fillMaxSize().clip(MaterialTheme.shapes.large), contentScale = ContentScale.Crop)
-            }
+            art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
         }
-        Spacer(Modifier.height(8.dp))
-        Text(
-            now.title.ifEmpty { "Nothing playing" },
-            style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
-            maxLines = 1, overflow = TextOverflow.Ellipsis,
-        )
-        Text(
-            listOf(now.artist, now.album).filter { it.isNotEmpty() }.joinToString(" - "),
-            style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant,
-            maxLines = 1, overflow = TextOverflow.Ellipsis,
-        )
-        now.error?.let { Text(it, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.error, maxLines = 2) }
+    }
+}
 
-        if (now.durationMs > 0) {
-            WavyProgress(
-                fraction = position.toFloat() / now.durationMs,
-                playing = now.state == PlaybackState.STATE_PLAYING,
-                onSeek = { media.seek((it * now.durationMs).toLong()) },
-                modifier = Modifier.padding(vertical = 4.dp),
+/**
+ * Everything about the track and every control for it, read top to bottom: title and artist,
+ * the seek bar, the transport, then like, shuffle and repeat as big icon-only buttons.
+ */
+@Composable
+private fun NowPlayingControls(now: NowPlaying, media: CarMedia, modifier: Modifier) {
+    Column(
+        modifier.verticalScroll(rememberScrollState()),
+        verticalArrangement = Arrangement.spacedBy(14.dp, Alignment.CenterVertically),
+    ) {
+        Column {
+            Text(
+                now.title.ifEmpty { "Nothing playing" },
+                style = MaterialTheme.typography.headlineMedium, fontWeight = FontWeight.Bold,
+                maxLines = 2, overflow = TextOverflow.Ellipsis,
             )
-        } else {
-            Spacer(Modifier.height(14.dp))
+            Text(
+                listOf(now.artist, now.album).filter { it.isNotEmpty() }.joinToString(" - "),
+                style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1, overflow = TextOverflow.Ellipsis,
+            )
+            now.error?.let { Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.error, maxLines = 2) }
         }
+        PlayerProgress(now, media, Modifier.fillMaxWidth())
+        TransportRow(now, media, skip = 60.dp, modifier = Modifier.fillMaxWidth())
+        PlayModeRow(now, media, size = 56.dp, modifier = Modifier.fillMaxWidth(), maxOther = 2)
+    }
+}
 
-        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(8.dp)) {
-            IconButton(onClick = media::previous, enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_PREVIOUS), modifier = Modifier.size(56.dp)) {
-                Icon(MediaIcons.Previous, "Previous", Modifier.size(32.dp))
-            }
-            FilledIconButton(onClick = media::togglePlay, modifier = Modifier.size(68.dp)) {
-                Icon(if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow, if (now.playing) "Pause" else "Play", Modifier.size(40.dp))
-            }
-            IconButton(onClick = media::next, enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_NEXT), modifier = Modifier.size(56.dp)) {
-                Icon(MediaIcons.Next, "Next", Modifier.size(32.dp))
-            }
-        }
-
-        // Whatever extra buttons the app publishes (shuffle, repeat, like), by name: their
-        // icons are resources inside the app's own package.
-        Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
-            now.custom.take(3).forEach { action ->
-                TextButton(onClick = { media.custom(action) }) { Text(action.name, maxLines = 1, overflow = TextOverflow.Ellipsis) }
-            }
+/**
+ * The player beside the browse list, the queue and the lyrics: no art, which the list needs the
+ * room for, just what's playing, the seek bar and the controls.
+ */
+@Composable
+private fun CompactPlayer(now: NowPlaying, media: CarMedia, modifier: Modifier) {
+    Column(
+        modifier.verticalScroll(rememberScrollState()),
+        verticalArrangement = Arrangement.spacedBy(14.dp),
+    ) {
+        Column {
+            Text(
+                now.title.ifEmpty { "Nothing playing" },
+                style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.Bold,
+                maxLines = 2, overflow = TextOverflow.Ellipsis,
+            )
+            Text(
+                now.artist,
+                style = MaterialTheme.typography.bodyLarge, color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1, overflow = TextOverflow.Ellipsis,
+            )
         }
+        PlayerProgress(now, media, Modifier.fillMaxWidth())
+        TransportRow(now, media, skip = 52.dp, modifier = Modifier.fillMaxWidth())
+        PlayModeRow(now, media, size = 48.dp, modifier = Modifier.fillMaxWidth())
     }
 }
 
@@ -307,15 +558,22 @@ private fun NowPlayingPanel(now: NowPlaying, media: CarMedia, modifier: Modifier
 @Composable
 private fun BrowsePanel(browse: app.seb3thehacker.gearslip.media.BrowseState, media: CarMedia, appLabel: String, modifier: Modifier) {
     Column(modifier) {
-        Row(verticalAlignment = Alignment.CenterVertically) {
-            if (media.canGoUp) {
-                IconButton(onClick = media::up) { Icon(Icons.Filled.ArrowBack, "Up") }
+        // At the library root there's no trail and nowhere to go up to, so there's nothing this
+        // row could say that the app's name in the top-left corner hasn't already - showing it
+        // again here (as "Browse", or as the app's own name) was just the same label twice.
+        if (media.canGoUp || browse.trail.isNotEmpty()) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                if (media.canGoUp) {
+                    GsIconButton(Icons.Filled.ArrowBack, "Up", media::up)
+                }
+                browse.trail.lastOrNull()?.let {
+                    Text(
+                        it,
+                        style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
+                        maxLines = 1, overflow = TextOverflow.Ellipsis,
+                    )
+                }
             }
-            Text(
-                browse.trail.lastOrNull() ?: "Browse",
-                style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
-                maxLines = 1, overflow = TextOverflow.Ellipsis,
-            )
         }
         when {
             browse.loading -> Notice("Loading…", null)
@@ -332,20 +590,75 @@ private fun BrowsePanel(browse: app.seb3thehacker.gearslip.media.BrowseState, me
     }
 }
 
+// --- up next -----------------------------------------------------------------------------------
+
+/**
+ * Whatever the app has queued up, starting right after the track that's playing now - not the
+ * whole queue from the top, which would just repeat what the player beside it already shows. Apps
+ * that never publish a queue (many don't) show an empty notice rather than a permanently blank tab.
+ */
 @Composable
-private fun EntryRow(entry: MediaEntry, media: CarMedia) {
+private fun QueuePanel(queue: List<QueueTrack>, now: NowPlaying, media: CarMedia, modifier: Modifier) {
+    val upNext = remember(queue, now.activeQueueItemId) {
+        val current = queue.indexOfFirst { it.queueId == now.activeQueueItemId }
+        if (current >= 0) queue.drop(current + 1) else queue
+    }
+    Column(modifier) {
+        if (upNext.isEmpty()) {
+            Notice(
+                "Nothing queued.",
+                "${if (now.title.isEmpty()) "Nothing playing" else "Only what's already playing"} - " +
+                    "not every app tells Gearslip what comes next.",
+            )
+        } else {
+            LazyColumn(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                items(upNext, key = { it.queueId }) { track -> QueueRow(track, media) }
+            }
+        }
+    }
+}
+
+@Composable
+private fun QueueRow(track: QueueTrack, media: CarMedia) {
     val context = LocalContext.current
-    val icon by produceState(entry.iconBitmap, entry.iconUri) {
-        value = entry.iconBitmap ?: MediaArt.load(context, entry.iconUri)
+    val icon by produceState(track.iconBitmap, track.iconUri) {
+        value = track.iconBitmap ?: MediaArt.load(context, track.iconUri)
     }
     Surface(
-        onClick = { media.select(entry) },
+        onClick = { media.playQueueItem(track) },
         shape = MaterialTheme.shapes.large,
         color = MaterialTheme.colorScheme.surfaceVariant,
         modifier = Modifier.fillMaxWidth(),
     ) {
         Row(Modifier.padding(10.dp), verticalAlignment = Alignment.CenterVertically) {
-            Box(Modifier.size(52.dp).clip(MaterialTheme.shapes.medium).background(MaterialTheme.colorScheme.surface)) {
+            Box(Modifier.size(62.dp).clip(MaterialTheme.shapes.medium).background(MaterialTheme.colorScheme.surface)) {
+                icon?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
+            }
+            Column(Modifier.weight(1f).padding(horizontal = 12.dp)) {
+                Text(track.title, style = MaterialTheme.typography.titleSmall, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                if (track.subtitle.isNotEmpty()) {
+                    Text(track.subtitle, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                }
+            }
+            Icon(Icons.Filled.PlayArrow, "Play", tint = MaterialTheme.colorScheme.onSurfaceVariant)
+        }
+    }
+}
+
+@Composable
+private fun EntryRow(entry: MediaEntry, media: CarMedia, onClick: () -> Unit = { media.select(entry) }) {
+    val context = LocalContext.current
+    val icon by produceState(entry.iconBitmap, entry.iconUri) {
+        value = entry.iconBitmap ?: MediaArt.load(context, entry.iconUri)
+    }
+    Surface(
+        onClick = onClick,
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceVariant,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(Modifier.padding(10.dp), verticalAlignment = Alignment.CenterVertically) {
+            Box(Modifier.size(62.dp).clip(MaterialTheme.shapes.medium).background(MaterialTheme.colorScheme.surface)) {
                 icon?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
             }
             Column(Modifier.weight(1f).padding(horizontal = 12.dp)) {
@@ -355,7 +668,7 @@ private fun EntryRow(entry: MediaEntry, media: CarMedia) {
                 }
             }
             if (entry.browsable && entry.playable) {
-                IconButton(onClick = { media.playAll(entry) }) { Icon(Icons.Filled.PlayArrow, "Play") }
+                GsIconButton(Icons.Filled.PlayArrow, "Play", { media.playAll(entry) })
             }
             if (entry.browsable) Icon(Icons.AutoMirrored.Filled.KeyboardArrowRight, null)
         }
@@ -369,8 +682,14 @@ internal object MediaIcons {
     /** The 3x3 app grid; not in material-icons-core. */
     val Apps = icon("Apps", "M4,8h4L8,4L4,4v4zM10,20h4v-4h-4v4zM4,20h4v-4L4,16v4zM4,14h4v-4L4,10v4zM10,14h4v-4h-4v4zM16,4v4h4L20,4h-4zM10,8h4L14,4h-4v4zM16,14h4v-4h-4v4zM16,20h4v-4h-4v4z")
     val Previous = icon("SkipPrevious", "M6,6h2v12L6,18zM9.5,12l8.5,6V6z")
+    val Equalizer = icon("Equalizer", "M10,20h4L14,4h-4v16zM4,20h4v-8L4,12v8zM16,9v11h4L20,9h-4z")
+    val Shuffle = icon("Shuffle", "M10.59,9.17L5.41,4 4,5.41l5.17,5.17 1.42,-1.41zM14.5,4l2.04,2.04L4,18.59 5.41,20 17.96,7.46 20,9.5L20,4h-5.5zM14.83,13.41l-1.41,1.41 3.13,3.13L14.5,20L20,20v-5.5l-2.04,2.04 -3.13,-3.13z")
+    val Repeat = icon("Repeat", "M7,7h10v3l4,-4 -4,-4v3L5,5v6h2L7,7zM17,17L7,17v-3l-4,4 4,4v-3h12v-6h-2v4z")
+    val RepeatOne = icon("RepeatOne", "M7,7h10v3l4,-4 -4,-4v3L5,5v6h2L7,7zM17,17L7,17v-3l-4,4 4,4v-3h12v-6h-2v4zM13,15L13,9h-1l-2,1v1h1.5v4L13,15z")
+    /** A screen with a filled right-hand panel: "put the player beside the map". */
+    val DockRight = icon("DockRight", "M2,4h20v16H2zM4,6h10v12H4z", PathFillType.EvenOdd)
 
-    private fun icon(name: String, path: String) = ImageVector.Builder(
+    private fun icon(name: String, path: String, fillType: PathFillType = PathFillType.NonZero) = ImageVector.Builder(
         name, 24.dp, 24.dp, 24f, 24f,
-    ).addPath(addPathNodes(path), fill = SolidColor(androidx.compose.ui.graphics.Color.Black)).build()
+    ).addPath(addPathNodes(path), pathFillType = fillType, fill = SolidColor(androidx.compose.ui.graphics.Color.Black)).build()
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/MessagePopup.kt

@@ -0,0 +1,274 @@
+package app.seb3thehacker.gearslip.car
+
+import android.os.SystemClock
+import androidx.compose.foundation.background
+import androidx.compose.foundation.horizontalScroll
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.withFrameMillis
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.res.vectorResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.R
+import app.seb3thehacker.gearslip.car.theme.GsButton
+import app.seb3thehacker.gearslip.car.theme.GsIconButton
+import app.seb3thehacker.gearslip.car.theme.GsProgressBar
+import app.seb3thehacker.gearslip.car.theme.GsTone
+import app.seb3thehacker.gearslip.notify.CarNotification
+import app.seb3thehacker.gearslip.notify.CarNotifications
+import kotlinx.coroutines.delay
+
+/*
+ * A new message on the car screen: a card at the top right, over the player beside the map on
+ * Home, so the road stays in view. It offers two things - hear it, or answer it by voice - and
+ * shows [VoiceReply]'s progress once either starts. A bar along its bottom empties as the card
+ * runs out of time, whatever it's waiting to do: go away, or send.
+ */
+
+/** How long a new message stays up on its own. */
+private const val POPUP_MS = 5_000L
+
+/** When [this] popup goes away on its own. */
+private fun CarNotification.until() = shownAt + POPUP_MS
+
+/**
+ * Times the popup out. Each new message in the same chat starts the clock again. A voice reply
+ * covers the card while it runs; if the popup's time ran out meanwhile, it goes when the reply ends.
+ */
+@Composable
+internal fun PopupTimer() {
+    val popup by CarNotifications.popup.collectAsState()
+    val voice by VoiceReply.state.collectAsState()
+    val n = popup ?: return
+    val busy = voice.phase != VoiceReply.Phase.IDLE
+    LaunchedEffect(n.id, n.shownAt, busy) {
+        if (busy) return@LaunchedEffect
+        delay((n.until() - SystemClock.uptimeMillis()).coerceAtLeast(0L))
+        CarNotifications.dismissPopup(n.id)
+    }
+}
+
+@Composable
+internal fun ReadGlyph(modifier: Modifier = Modifier) =
+    Icon(ImageVector.vectorResource(R.drawable.volume_up_24), null, modifier)
+
+@Composable
+internal fun ReplyGlyph(modifier: Modifier = Modifier) =
+    Icon(ImageVector.vectorResource(R.drawable.voice_selection_24), null, modifier)
+
+/** "Alex", or "Alex · 3 new" when a burst of messages from one chat has been merged. */
+private fun CarNotification.heading(): String {
+    val who = title.ifBlank { appLabel }
+    return if (burst > 1) "$who · $burst new" else who
+}
+
+/** The card. It shows the voice reply too, wherever that was started from. */
+@Composable
+fun NotificationPopup(showNew: Boolean, modifier: Modifier = Modifier) {
+    val popup by CarNotifications.popup.collectAsState()
+    val voice by VoiceReply.state.collectAsState()
+    val target = voice.target
+    if (voice.phase != VoiceReply.Phase.IDLE && target != null) {
+        PopupCard(voice.until, voice.span, modifier, held = voice.held) { VoiceReplyBody(voice, target) }
+        return
+    }
+    val n = popup?.takeIf { showNew } ?: return
+    PopupCard(n.until(), POPUP_MS, modifier) {
+        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+            NotificationIcon(n, size = 44.dp)
+            Column(Modifier.weight(1f)) {
+                Text(n.heading(), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                Text(n.text, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
+            }
+            GsIconButton(Icons.Filled.Close, "Dismiss", { CarNotifications.dismissPopup(n.id) }, size = 40.dp, iconSize = 20.dp)
+        }
+        Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+            GsButton(onClick = { VoiceReply.read(n) }, tone = GsTone.Neutral, modifier = Modifier.weight(1f)) {
+                ReadGlyph(Modifier.size(20.dp))
+                Text("Read", Modifier.padding(start = 8.dp))
+            }
+            if (n.reply != null) {
+                GsButton(onClick = { VoiceReply.reply(n) }, modifier = Modifier.weight(1f)) {
+                    ReplyGlyph(Modifier.size(20.dp))
+                    Text("Reply", Modifier.padding(start = 8.dp))
+                }
+            }
+        }
+    }
+}
+
+/**
+ * The card's frame. When [until] is set, a bar along the bottom empties over [span] ms, so the
+ * driver sees at a glance how long is left before the card acts. A [held] countdown shows its bar
+ * standing still.
+ */
+@Composable
+private fun PopupCard(until: Long, span: Long, modifier: Modifier, held: Float = 0f, content: @Composable () -> Unit) {
+    Surface(
+        shape = RoundedCornerShape(20.dp),
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        contentColor = MaterialTheme.colorScheme.onSurface,
+        shadowElevation = 8.dp,
+        modifier = modifier.padding(12.dp).widthIn(min = 300.dp, max = 400.dp).fillMaxWidth(0.34f),
+    ) {
+        Column(Modifier.padding(14.dp), verticalArrangement = Arrangement.spacedBy(12.dp)) {
+            content()
+            if (until > 0L && span > 0L) {
+                val left by rememberTimeLeft(until, span)
+                GsProgressBar(left, Modifier.fillMaxWidth(), height = 14.dp)
+            } else if (held > 0f) {
+                GsProgressBar(held, Modifier.fillMaxWidth(), height = 14.dp)
+            }
+        }
+    }
+}
+
+/** The share of [span] still to go before [until], updated every frame so the bar moves smoothly. */
+@Composable
+private fun rememberTimeLeft(until: Long, span: Long) = produceState(fractionLeft(until, span), until, span) {
+    // The state outlives a change of deadline, so start from the new one rather than the old value.
+    value = fractionLeft(until, span)
+    while (value > 0f) {
+        withFrameMillis { value = fractionLeft(until, span) }
+    }
+}
+
+private fun fractionLeft(until: Long, span: Long): Float =
+    ((until - SystemClock.uptimeMillis()).toFloat() / span).coerceIn(0f, 1f)
+
+/** Each step of a voice reply, with the buttons that fit it. */
+@Composable
+private fun VoiceReplyBody(s: VoiceReply.State, n: CarNotification) {
+    val navigator = LocalCarNavigator.current
+    val who = n.title.ifBlank { n.appLabel }
+    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+        when (s.phase) {
+            VoiceReply.Phase.OFFERING, VoiceReply.Phase.ASKING, VoiceReply.Phase.LISTENING -> ListeningDot()
+            VoiceReply.Phase.SENT -> Icon(Icons.Filled.Check, null, Modifier.size(32.dp), tint = MaterialTheme.colorScheme.primary)
+            else -> NotificationIcon(n, size = 44.dp)
+        }
+        Column(Modifier.weight(1f)) {
+            Text(voiceHeading(s, who), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold, maxLines = 1, overflow = TextOverflow.Ellipsis)
+            voiceDetail(s, n)?.let {
+                Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 3, overflow = TextOverflow.Ellipsis)
+            }
+        }
+    }
+    if (s.phase == VoiceReply.Phase.CONFIRMING) {
+        Text("Say “cancel” or “change it”", style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.primary)
+    }
+    if ((s.phase == VoiceReply.Phase.READ || s.phase == VoiceReply.Phase.OFFERING) && n.reply != null) {
+        QuickReplies(n)
+    }
+    Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+        val wide = Modifier.weight(1f)
+        when (s.phase) {
+            VoiceReply.Phase.READING, VoiceReply.Phase.READ -> {
+                GsButton(onClick = VoiceReply::cancel, tone = GsTone.Neutral, modifier = wide) {
+                    Text(if (s.phase == VoiceReply.Phase.READING) "Stop" else "Close")
+                }
+                if (n.reply != null) {
+                    GsButton(onClick = { VoiceReply.reply(n, readFirst = false) }, modifier = wide) {
+                        ReplyGlyph(Modifier.size(20.dp))
+                        Text("Reply", Modifier.padding(start = 8.dp))
+                    }
+                }
+            }
+            VoiceReply.Phase.OFFERING -> {
+                GsButton(onClick = VoiceReply::cancel, tone = GsTone.Neutral, modifier = wide) { Text("No") }
+                GsButton(onClick = { VoiceReply.reply(n, readFirst = false) }, modifier = wide) {
+                    ReplyGlyph(Modifier.size(20.dp))
+                    Text("Reply", Modifier.padding(start = 8.dp))
+                }
+            }
+            VoiceReply.Phase.ASKING, VoiceReply.Phase.LISTENING ->
+                GsButton(onClick = VoiceReply::cancel, tone = GsTone.Neutral, modifier = wide) { Text("Cancel") }
+            VoiceReply.Phase.CONFIRMING -> {
+                GsButton(onClick = VoiceReply::cancel, tone = GsTone.Neutral, modifier = wide) { Text("Cancel") }
+                GsButton(onClick = VoiceReply::sendNow, modifier = wide) { Text("Send now") }
+            }
+            VoiceReply.Phase.ERROR -> {
+                GsButton(onClick = VoiceReply::cancel, tone = GsTone.Neutral, modifier = wide) { Text("Close") }
+                if (n.reply != null) {
+                    GsButton(onClick = { VoiceReply.reply(n, readFirst = false) }, tone = GsTone.Tonal, modifier = wide) { Text("Try again") }
+                    GsButton(
+                        onClick = { VoiceReply.cancel(); navigator.notifications(replyTo = n.key) },
+                        tone = GsTone.Neutral, modifier = wide,
+                    ) { Text("Type") }
+                }
+            }
+            VoiceReply.Phase.SENT, VoiceReply.Phase.IDLE -> Unit
+        }
+    }
+}
+
+private fun voiceHeading(s: VoiceReply.State, who: String): String = when (s.phase) {
+    VoiceReply.Phase.READING, VoiceReply.Phase.READ -> who
+    VoiceReply.Phase.OFFERING, VoiceReply.Phase.ASKING -> "Reply to $who"
+    VoiceReply.Phase.LISTENING -> "Listening"
+    VoiceReply.Phase.CONFIRMING -> "Sending to $who"
+    VoiceReply.Phase.SENT -> "Sent to $who"
+    VoiceReply.Phase.ERROR -> "Couldn't reply"
+    VoiceReply.Phase.IDLE -> ""
+}
+
+private fun voiceDetail(s: VoiceReply.State, n: CarNotification): String? = when (s.phase) {
+    VoiceReply.Phase.READING, VoiceReply.Phase.READ -> n.text
+    VoiceReply.Phase.OFFERING -> s.heard.ifBlank { "Do you want to reply? Say yes or no." }
+    VoiceReply.Phase.ASKING -> "Get ready to say your reply."
+    VoiceReply.Phase.LISTENING -> s.heard.ifBlank { "Say your reply" }
+    VoiceReply.Phase.CONFIRMING, VoiceReply.Phase.SENT -> "“${s.heard}”"
+    VoiceReply.Phase.ERROR -> s.error
+    VoiceReply.Phase.IDLE -> null
+}
+
+/** Ready-made answers, one tap each: sent at once, with no voice. */
+@Composable
+internal fun QuickReplies(n: CarNotification, modifier: Modifier = Modifier) {
+    Row(
+        modifier.fillMaxWidth().horizontalScroll(rememberScrollState()),
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        VoiceReply.quickReplies().forEach { text ->
+            GsButton(onClick = { VoiceReply.quickReply(n, text) }, tone = GsTone.Neutral) {
+                Text(text, style = MaterialTheme.typography.labelLarge, maxLines = 1)
+            }
+        }
+    }
+}
+
+@Composable
+private fun ListeningDot(modifier: Modifier = Modifier) {
+    Box(
+        modifier.size(44.dp).clip(CircleShape).background(MaterialTheme.colorScheme.primary),
+        contentAlignment = Alignment.Center,
+    ) {
+        MicGlyph(Modifier.size(24.dp))
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/MessagesScreen.kt

@@ -0,0 +1,198 @@
+package app.seb3thehacker.gearslip.car
+
+import app.seb3thehacker.gearslip.car.theme.*
+import android.content.Intent
+import android.provider.Settings
+import androidx.compose.animation.animateContentSize
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.notify.CarNotification
+import app.seb3thehacker.gearslip.notify.CarNotifications
+import app.seb3thehacker.gearslip.notify.ChatLine
+import java.text.DateFormat
+import java.util.Date
+
+/** Lines a collapsed conversation shows; tapping it shows the rest the app sent. */
+private const val COLLAPSED_LINES = 2
+
+/**
+ * A messaging app's recent conversations, the way Android Auto shows them: the app has no car
+ * screen of its own, so each thread comes from the notification it has on the phone, newest
+ * first, with reply and mark-as-read when the app offers them.
+ */
+@Composable
+fun MessagesScreen(packageName: String) {
+    val history by CarNotifications.history.collectAsState()
+    val listening by CarNotifications.listening.collectAsState()
+    val navigator = LocalCarNavigator.current
+    val context = LocalContext.current.applicationContext
+    val entry = remember(packageName) { findEntry(MESSAGING_PREFIX + packageName) }
+    val label = entry?.label ?: history.firstOrNull { it.packageName == packageName }?.appLabel ?: "Messages"
+    val threads = history.filter { it.packageName == packageName }
+
+    LaunchedEffect(history) { CarNotifications.dismissPopupFrom(packageName) }
+
+    Column(Modifier.fillMaxSize().padding(16.dp), verticalArrangement = Arrangement.spacedBy(16.dp)) {
+        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+            GsIconButton(Icons.AutoMirrored.Filled.ArrowBack, "Back", navigator::back)
+            entry?.icon?.let { Image(it, contentDescription = null, modifier = Modifier.size(36.dp).clip(RoundedCornerShape(8.dp))) }
+            Text(label, style = MaterialTheme.typography.headlineSmall, fontWeight = FontWeight.Bold)
+        }
+
+        if (!listening) {
+            AccessBanner {
+                context.startActivity(
+                    Intent(Settings.ACTION_NOTIFICATION_LISTENER_SETTINGS).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
+                )
+            }
+        }
+
+        if (threads.isEmpty()) {
+            Text(
+                "No recent messages. New $label messages appear here as they arrive on the phone.",
+                style = MaterialTheme.typography.bodyLarge,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        } else {
+            LazyColumn(
+                verticalArrangement = Arrangement.spacedBy(10.dp),
+                contentPadding = PaddingValues(bottom = 16.dp),
+            ) {
+                items(threads, key = { it.key }) { n ->
+                    ConversationCard(
+                        n,
+                        onRead = { VoiceReply.read(n) },
+                        onReply = { VoiceReply.reply(n) },
+                        onMarkRead = { CarNotifications.markThreadRead(context, n) },
+                    )
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun ConversationCard(n: CarNotification, onRead: () -> Unit, onReply: () -> Unit, onMarkRead: () -> Unit) {
+    var expanded by rememberSaveable(n.key) { mutableStateOf(false) }
+    // An app that posts plain notifications instead of a conversation still gets one line.
+    val lines = n.lines.ifEmpty { listOf(ChatLine(n.title.ifBlank { n.appLabel }, n.text.ifBlank { n.title }, n.postedAt)) }
+    val shown = if (expanded) lines else lines.takeLast(COLLAPSED_LINES)
+    val dim = n.read || n.replied
+    var quick by rememberSaveable(n.key) { mutableStateOf(false) }
+
+    Surface(
+        shape = RoundedCornerShape(16.dp),
+        color = MaterialTheme.colorScheme.surfaceContainer,
+        modifier = Modifier
+            .fillMaxWidth()
+            .animateContentSize()
+            .clickable(enabled = lines.size > COLLAPSED_LINES) { expanded = !expanded },
+    ) {
+        Row(
+            Modifier.padding(14.dp),
+            verticalAlignment = Alignment.Top,
+            horizontalArrangement = Arrangement.spacedBy(14.dp),
+        ) {
+            NotificationIcon(n, size = 52.dp)
+            Column(Modifier.weight(1f), verticalArrangement = Arrangement.spacedBy(4.dp)) {
+                Row(verticalAlignment = Alignment.CenterVertically) {
+                    Text(
+                        n.title.ifBlank { n.appLabel },
+                        style = MaterialTheme.typography.titleLarge,
+                        fontWeight = if (dim) FontWeight.Medium else FontWeight.Bold,
+                        maxLines = 1,
+                        overflow = TextOverflow.Ellipsis,
+                        modifier = Modifier.weight(1f, fill = false),
+                    )
+                    Text(
+                        "  ·  ${DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(n.postedAt))}",
+                        style = MaterialTheme.typography.labelLarge,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        maxLines = 1,
+                    )
+                }
+                if (!expanded && lines.size > COLLAPSED_LINES) {
+                    Text(
+                        "${lines.size - COLLAPSED_LINES} earlier",
+                        style = MaterialTheme.typography.labelMedium,
+                        color = MaterialTheme.colorScheme.primary,
+                    )
+                }
+                shown.forEach { MessageLine(it, showSender = n.isGroup) }
+                if (quick) QuickReplies(n, Modifier.padding(top = 6.dp))
+            }
+            Column(horizontalAlignment = Alignment.End, verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                if (n.replied) {
+                    Icon(Icons.Filled.Check, contentDescription = "Replied", tint = MaterialTheme.colorScheme.primary)
+                }
+                GsButton(onClick = onRead, tone = GsTone.Neutral) {
+                    ReadGlyph(Modifier.size(20.dp))
+                    Text("Read", Modifier.padding(start = 8.dp))
+                }
+                if (n.reply != null) {
+                    GsButton(onClick = onReply, tone = GsTone.Tonal) {
+                        ReplyGlyph(Modifier.size(20.dp))
+                        Text("Reply", Modifier.padding(start = 8.dp))
+                    }
+                }
+                if (n.reply != null) {
+                    GsButton(onClick = { quick = !quick }, tone = GsTone.Neutral) {
+                        Text(if (quick) "Hide quick replies" else "Quick reply")
+                    }
+                }
+                if (n.markRead != null) {
+                    GsButton(onClick = onMarkRead, tone = GsTone.Neutral) { Text("Mark read") }
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun MessageLine(line: ChatLine, showSender: Boolean) {
+    val who = when {
+        line.sender == null -> "You: "
+        showSender -> "${line.sender}: "
+        else -> ""
+    }
+    Text(
+        who + line.text,
+        style = MaterialTheme.typography.bodyLarge,
+        color = if (line.sender == null) MaterialTheme.colorScheme.onSurfaceVariant else MaterialTheme.colorScheme.onSurface,
+        maxLines = 3,
+        overflow = TextOverflow.Ellipsis,
+    )
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/NavApps.kt

@@ -0,0 +1,299 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Call
+import androidx.compose.material.icons.filled.Info
+import androidx.compose.material.icons.filled.Search
+import androidx.compose.material.icons.filled.Settings
+import androidx.compose.material.icons.filled.Share
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.car.theme.GsButton
+import app.seb3thehacker.gearslip.car.theme.GsTone
+import app.seb3thehacker.gearslip.host.CarAppConnection
+import app.seb3thehacker.gearslip.media.CarMedia
+import app.seb3thehacker.gearslip.CarFocus
+import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.ui.graphics.vector.PathParser
+
+/** What a built-in app's id carries in a pin, so it can't collide with an installed app's component. */
+internal const val BUILT_IN_PREFIX = "gearslip:"
+
+/** Material's "directions car", drawn here because only the core icon set is bundled. */
+private val CarGlyph: ImageVector = ImageVector.Builder("Car", 24.dp, 24.dp, 24f, 24f).addPath(
+    PathParser().parsePathString(
+        "M18.92,6.01C18.72,5.42 18.16,5 17.5,5h-11c-0.66,0 -1.21,0.42 -1.42,1.01L3,12v8c0,0.55 0.45,1 1,1h1" +
+            "c0.55,0 1,-0.45 1,-1v-1h12v1c0,0.55 0.45,1 1,1h1c0.55,0 1,-0.45 1,-1v-8l-2.08,-5.99z" +
+            "M6.5,16c-0.83,0 -1.5,-0.67 -1.5,-1.5S5.67,13 6.5,13s1.5,0.67 1.5,1.5S7.33,16 6.5,16z" +
+            "M17.5,16c-0.83,0 -1.5,-0.67 -1.5,-1.5s0.67,-1.5 1.5,-1.5 1.5,0.67 1.5,1.5 -0.67,1.5 -1.5,1.5z" +
+            "M5,11l1.5,-4.5h11L19,11L5,11z",
+    ).toNodes(),
+    fill = SolidColor(Color.Black),
+).build()
+
+/**
+ * One of Gearslip's own apps: a screen, with nothing running behind it once you leave. [screen] is
+ * null for an action like Exit, which has no screen and so never shows as open.
+ */
+internal class BuiltInApp(
+    val id: String,
+    val label: String,
+    val glyph: ImageVector,
+    val screen: CarScreen?,
+    val open: (CarNavigator) -> Unit,
+)
+
+internal object BuiltInApps {
+    val Web = BuiltInApp("web", "Browser", Icons.Filled.Search, CarScreen.App("web")) { it.open("web") }
+    val ScreenSharing = BuiltInApp("phone", "Screen sharing", Icons.Filled.Share, CarScreen.App("phone")) { it.open("phone") }
+    val Phone = BuiltInApp("dialer", "Phone", Icons.Filled.Call, CarScreen.App("dialer")) { it.open("dialer") }
+    val VehicleData = BuiltInApp("vehicle", "Vehicle data", Icons.Filled.Info, CarScreen.VehicleData) { it.vehicleData() }
+    val Settings = BuiltInApp("settings", "Settings", Icons.Filled.Settings, CarScreen.Settings) { it.settings() }
+
+    /** Hands the screen back to the car's own interface, like Android Auto's Exit. */
+    val Exit = BuiltInApp("exit", "Exit", CarGlyph, screen = null) { CarFocus.exitToCar() }
+
+    val all = listOf(Web, ScreenSharing, Phone, VehicleData, Settings, Exit)
+    val entries: List<Entry> = all.map { Entry(it.label, icon = null, builtIn = it) }
+}
+
+/** Vehicle data is experimental: raw, unverified sensor labels (see [CarSensors]). */
+@Composable
+internal fun rememberVehicleDataShown(): Boolean {
+    val experimental by CarSettings.experimentalFeaturesEnabled.collectAsState()
+    val sensors by CarSettings.carSensorsEnabled.collectAsState()
+    return experimental && sensors
+}
+
+/**
+ * Where an open app lives - decides where tapping it goes and how it closes. Gearslip's own
+ * apps have no connection behind them, so [SCREEN] is simply "on screen right now".
+ */
+internal enum class RunningSlot { NAV, BROWSE, MEDIA, SCREEN }
+
+/**
+ * Apps open right now, as component id to where they live, in the order the nav bar shows them:
+ * the map, then a browsed templated app, then the media app, then whichever built-in app is on
+ * screen. The map and a browsed app count from the moment they start connecting until they're
+ * closed. The media app counts while it has something loaded to play - the same rule the nav
+ * bar's player follows, so the two always show up together - or while its own screen is up.
+ */
+@Composable
+internal fun rememberRunningApps(): Map<String, RunningSlot> {
+    val navStatus by CarServices.nav.status.collectAsState()
+    val browseStatus by CarServices.browse.status.collectAsState()
+    val mediaApp by CarServices.mediaApp.collectAsState()
+    val mediaPhase by CarServices.media.phase.collectAsState()
+    val now by CarServices.media.now.collectAsState()
+    val current = LocalCarNavigator.current.current
+
+    fun CarAppConnection.liveId(phase: CarAppConnection.Phase) =
+        connectedComponent?.flattenToString()?.takeIf {
+            phase == CarAppConnection.Phase.BINDING ||
+                phase == CarAppConnection.Phase.HANDSHAKE ||
+                phase == CarAppConnection.Phase.RUNNING
+        }
+
+    return buildMap {
+        CarServices.nav.liveId(navStatus.phase)?.let { put(it, RunningSlot.NAV) }
+        CarServices.browse.liveId(browseStatus.phase)?.let { put(it, RunningSlot.BROWSE) }
+        val mediaLive = when (mediaPhase) {
+            CarMedia.Phase.CONNECTING -> true
+            CarMedia.Phase.READY -> now.isActive || current == CarScreen.Media
+            else -> false
+        }
+        mediaApp?.component?.flattenToString()?.takeIf { mediaLive }?.let { put(it, RunningSlot.MEDIA) }
+        BuiltInApps.all.firstOrNull { it.screen != null && it.screen == current }?.let { put(BUILT_IN_PREFIX + it.id, RunningSlot.SCREEN) }
+        (current as? CarScreen.Messages)?.let { put(MESSAGING_PREFIX + it.packageName, RunningSlot.SCREEN) }
+    }
+}
+
+/** The screen an open app is showing on, so its nav bar icon can stay pressed in while it's up. */
+internal fun RunningSlot.isShowing(current: CarScreen): Boolean = when (this) {
+    RunningSlot.NAV -> current == CarScreen.Home
+    RunningSlot.BROWSE -> current == CarScreen.Browse
+    RunningSlot.MEDIA -> current == CarScreen.Media
+    RunningSlot.SCREEN -> true
+}
+
+/**
+ * Brings an app up: back to its screen if it's already open - never a reconnect, which would
+ * throw away the route or restart the session - otherwise a fresh launch.
+ */
+internal fun openApp(entry: Entry, slot: RunningSlot?, navigator: CarNavigator, frame: CarEnvironment.Frame) {
+    when (slot) {
+        RunningSlot.NAV -> navigator.home()
+        RunningSlot.BROWSE -> navigator.browse(entry.label)
+        RunningSlot.MEDIA -> navigator.media()
+        RunningSlot.SCREEN -> Unit
+        null -> launchEntry(entry, navigator, frame)
+    }
+}
+
+internal fun closeApp(slot: RunningSlot, navigator: CarNavigator) {
+    when (slot) {
+        RunningSlot.NAV -> CarServices.stopNav()
+        RunningSlot.BROWSE -> CarServices.stopBrowse()
+        RunningSlot.MEDIA -> CarServices.closeMedia()
+        RunningSlot.SCREEN -> Unit
+    }
+    if (slot != RunningSlot.NAV && slot.isShowing(navigator.current)) navigator.back()
+}
+
+/**
+ * What a long press on an app offers - pin it to or unpin it from the nav bar, move it along the
+ * launcher, and close it if it's open - as a card in the middle of the screen with car-sized buttons, over a scrim that
+ * dismisses it. Drawn in the car UI's own layout rather than a system popup window, which the
+ * car's virtual display has no reason to host well.
+ */
+@Composable
+internal fun AppMenu(navigator: CarNavigator, running: Map<String, RunningSlot>) {
+    val id = navigator.appMenu ?: return
+    val entry = findEntry(id)
+    if (entry == null) {
+        navigator.dismissAppMenu()
+        return
+    }
+    val pinned by CarSettings.pinnedApps.collectAsState()
+    val isPinned = id in pinned
+    val barFull = !isPinned && pinned.size >= CarSettings.MAX_PINNED
+    val slot = running[id]
+
+    Box(
+        Modifier
+            .fillMaxSize()
+            .background(Color.Black.copy(alpha = 0.5f))
+            .clickable(
+                interactionSource = remember { MutableInteractionSource() },
+                indication = null,
+                onClick = navigator::dismissAppMenu,
+            ),
+        contentAlignment = Alignment.Center,
+    ) {
+        Surface(
+            shape = RoundedCornerShape(24.dp),
+            color = MaterialTheme.colorScheme.surfaceContainerHigh,
+            // Swallows taps on the card itself, so only the scrim around it dismisses.
+            modifier = Modifier
+                .widthIn(max = 420.dp)
+                .clickable(
+                    interactionSource = remember { MutableInteractionSource() },
+                    indication = null,
+                    onClick = {},
+                ),
+        ) {
+            Column(Modifier.padding(20.dp), verticalArrangement = Arrangement.spacedBy(12.dp)) {
+                Row(verticalAlignment = Alignment.CenterVertically) {
+                    entry.icon?.let { Image(it, null, Modifier.size(44.dp).clip(RoundedCornerShape(10.dp))) }
+                    entry.builtIn?.let { Icon(it.glyph, null, Modifier.size(36.dp)) }
+                    Text(
+                        entry.label,
+                        style = MaterialTheme.typography.titleLarge,
+                        fontWeight = FontWeight.SemiBold,
+                        modifier = Modifier.padding(start = 14.dp),
+                    )
+                }
+                GsButton(
+                    onClick = {
+                        CarSettings.togglePin(id)
+                        navigator.dismissAppMenu()
+                    },
+                    tone = GsTone.Tonal,
+                    enabled = !barFull,
+                    modifier = Modifier.fillMaxWidth().height(56.dp),
+                ) {
+                    Text(
+                        when {
+                            isPinned -> "Unpin from nav bar"
+                            barFull -> "Nav bar is full (${CarSettings.MAX_PINNED} pinned)"
+                            else -> "Pin to nav bar"
+                        },
+                        style = MaterialTheme.typography.titleMedium,
+                    )
+                }
+                if (navigator.current == CarScreen.Apps) MoveButtons(id)
+                if (slot != null) {
+                    GsButton(
+                        onClick = {
+                            closeApp(slot, navigator)
+                            navigator.dismissAppMenu()
+                        },
+                        tone = GsTone.Danger,
+                        modifier = Modifier.fillMaxWidth().height(56.dp),
+                    ) { Text("Close app", style = MaterialTheme.typography.titleMedium) }
+                }
+                GsButton(
+                    onClick = navigator::dismissAppMenu,
+                    tone = GsTone.Neutral,
+                    modifier = Modifier.fillMaxWidth().height(56.dp),
+                ) { Text("Cancel", style = MaterialTheme.typography.titleMedium) }
+            }
+        }
+    }
+}
+
+/**
+ * Moves the app one place left or right on the launcher. The menu stays open so a tile can be
+ * walked several places, and the grid behind the scrim shows where it went.
+ */
+@Composable
+private fun MoveButtons(id: String) {
+    val custom by CarSettings.appOrder.collectAsState()
+    val order = launcherOrder(rememberAllEntries(), rememberVehicleDataShown(), custom).mapNotNull { it.componentId }
+    val index = order.indexOf(id)
+    if (index < 0) return
+    fun move(by: Int) {
+        val next = order.toMutableList()
+        java.util.Collections.swap(next, index, index + by)
+        CarSettings.setAppOrder(next)
+    }
+    Row(horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+        GsButton(
+            onClick = { move(-1) },
+            tone = GsTone.Tonal,
+            enabled = index > 0,
+            modifier = Modifier.weight(1f).height(56.dp),
+        ) { Text("Move left", style = MaterialTheme.typography.titleMedium) }
+        GsButton(
+            onClick = { move(1) },
+            tone = GsTone.Tonal,
+            enabled = index < order.lastIndex,
+            modifier = Modifier.weight(1f).height(56.dp),
+        ) { Text("Move right", style = MaterialTheme.typography.titleMedium) }
+    }
+    if (custom.isNotEmpty()) {
+        GsButton(
+            onClick = { CarSettings.setAppOrder(emptyList()) },
+            tone = GsTone.Neutral,
+            modifier = Modifier.fillMaxWidth().height(56.dp),
+        ) { Text("Reset app order", style = MaterialTheme.typography.titleMedium) }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/NotificationsScreen.kt

@@ -1,9 +1,9 @@
 package app.seb3thehacker.gearslip.car
 
+import app.seb3thehacker.gearslip.car.theme.*
 import android.content.Intent
 import android.provider.Settings
 import androidx.compose.foundation.Image
-import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -13,8 +13,6 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.lazy.LazyColumn
-import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
@@ -23,10 +21,7 @@ import androidx.compose.material.icons.filled.Check
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Notifications
 import androidx.compose.material.icons.filled.Warning
-import androidx.compose.material3.Button
-import androidx.compose.material3.FilledTonalButton
 import androidx.compose.material3.Icon
-import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
@@ -35,6 +30,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.key
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
@@ -52,34 +48,40 @@ import kotlinx.coroutines.delay
 import java.text.DateFormat
 import java.util.Date
 
-/** The notification history, with a reply pane for anything the sending app lets us answer. */
+/**
+ * Replying to one notification. The list itself lives on the dashboard (see
+ * [NotificationsSection]); with nothing to reply to, this is just the dashboard.
+ */
 @Composable
 fun NotificationsScreen(replyTo: String?) {
     val history by CarNotifications.history.collectAsState()
-    var replying by remember(replyTo) { mutableStateOf(replyTo) }
-
-    // Anything arriving while this is open is being looked at, so it never counts as unread.
-    LaunchedEffect(history) { CarNotifications.markRead() }
-
-    val target = history.firstOrNull { it.key == replying && it.reply != null }
+    val navigator = LocalCarNavigator.current
+    val target = history.firstOrNull { it.key == replyTo && it.reply != null }
     if (target != null) {
-        ReplyPane(target, onDone = { replying = null })
+        ReplyPane(target, onDone = navigator::back)
     } else {
-        NotificationList(history, onReply = { replying = it.key })
+        CarDashboardScreen()
     }
 }
 
+/**
+ * The notification history, under the calendar on the dashboard. Replying opens its own pane.
+ * Anything arriving while this is on screen is being looked at, so it never counts as unread.
+ */
 @Composable
-private fun NotificationList(history: List<CarNotification>, onReply: (CarNotification) -> Unit) {
+fun NotificationsSection() {
+    val history by CarNotifications.history.collectAsState()
     val listening by CarNotifications.listening.collectAsState()
+    val navigator = LocalCarNavigator.current
     val context = LocalContext.current.applicationContext
+    LaunchedEffect(history) { CarNotifications.markRead() }
 
-    Column(Modifier.fillMaxSize().padding(horizontal = 20.dp, vertical = 12.dp)) {
+    Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
         Row(verticalAlignment = Alignment.CenterVertically) {
             Text(
                 "Notifications",
-                style = MaterialTheme.typography.headlineMedium,
-                fontWeight = FontWeight.Bold,
+                style = MaterialTheme.typography.titleMedium,
+                color = MaterialTheme.colorScheme.primary,
                 modifier = Modifier.weight(1f),
             )
             if (history.isNotEmpty()) TextButton(onClick = CarNotifications::clear) { Text("Clear all") }
@@ -94,22 +96,21 @@ private fun NotificationList(history: List<CarNotification>, onReply: (CarNotifi
         }
 
         if (history.isEmpty()) {
-            Box(Modifier.weight(1f).fillMaxWidth(), contentAlignment = Alignment.Center) {
-                Text(
-                    "Nothing yet. New notifications from the phone will show up here.",
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                )
-            }
+            Text(
+                "Nothing yet. New notifications from the phone will show up here.",
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
         } else {
-            LazyColumn(Modifier.weight(1f), verticalArrangement = Arrangement.spacedBy(8.dp)) {
-                items(history, key = { it.key }) { NotificationRow(it, onReply) }
+            history.forEach { n ->
+                key(n.key) { NotificationRow(n) { navigator.notifications(replyTo = it.key) } }
             }
         }
     }
 }
 
 @Composable
-private fun AccessBanner(onOpen: () -> Unit) {
+internal fun AccessBanner(onOpen: () -> Unit) {
     Surface(
         shape = MaterialTheme.shapes.large,
         color = MaterialTheme.colorScheme.errorContainer,
@@ -127,7 +128,7 @@ private fun AccessBanner(onOpen: () -> Unit) {
                 style = MaterialTheme.typography.bodyMedium,
                 modifier = Modifier.weight(1f),
             )
-            Button(onClick = onOpen) { Text("Open") }
+            GsButton(onClick = onOpen) { Text("Open") }
         }
     }
 }
@@ -160,14 +161,17 @@ private fun NotificationRow(n: CarNotification, onReply: (CarNotification) -> Un
             }
             when {
                 n.replied -> Icon(Icons.Filled.Check, contentDescription = "Replied", tint = MaterialTheme.colorScheme.primary)
-                n.reply != null -> FilledTonalButton(onClick = { onReply(n) }) { Text("Reply") }
+                n.reply != null -> GsButton(onClick = { VoiceReply.reply(n) }, tone = GsTone.Tonal) {
+                    ReplyGlyph(Modifier.size(20.dp))
+                    Text("Reply", Modifier.padding(start = 8.dp))
+                }
             }
         }
     }
 }
 
 @Composable
-private fun NotificationIcon(n: CarNotification, size: androidx.compose.ui.unit.Dp = 44.dp) {
+internal fun NotificationIcon(n: CarNotification, size: androidx.compose.ui.unit.Dp = 44.dp) {
     val icon = n.icon
     if (icon != null) {
         Image(icon.asImageBitmap(), contentDescription = null, modifier = Modifier.size(size).clip(RoundedCornerShape(10.dp)))
@@ -194,7 +198,7 @@ private fun ReplyPane(n: CarNotification, onDone: () -> Unit) {
             verticalAlignment = Alignment.CenterVertically,
             horizontalArrangement = Arrangement.spacedBy(8.dp),
         ) {
-            IconButton(onClick = onDone) { Icon(Icons.AutoMirrored.Filled.ArrowBack, contentDescription = "Back") }
+            GsIconButton(Icons.AutoMirrored.Filled.ArrowBack, "Back", onDone)
             Surface(
                 shape = RoundedCornerShape(24.dp),
                 color = MaterialTheme.colorScheme.surfaceContainerHighest,
@@ -220,58 +224,9 @@ private fun ReplyPane(n: CarNotification, onDone: () -> Unit) {
             Text(n.text.ifBlank { n.title }, style = MaterialTheme.typography.bodyLarge, maxLines = 3, overflow = TextOverflow.Ellipsis)
         }
 
-        CarKeyboard(text, onTextChange = { text = it }, onSubmit = ::send, submitImage = Icons.AutoMirrored.Filled.Send)
+        CarKeyboard(
+            text, onTextChange = { text = it }, onSubmit = ::send,
+            submitImage = Icons.AutoMirrored.Filled.Send, onDismiss = onDone,
+        )
     }
 }
-
-/**
- * The popup shown over whatever the car is displaying. It times itself out, and tapping it opens
- * the history - or straight into a reply, when the app allows one.
- */
-@Composable
-fun NotificationPopup(modifier: Modifier = Modifier) {
-    val popup by CarNotifications.popup.collectAsState()
-    val navigator = LocalCarNavigator.current
-    val n = popup ?: return
-
-    LaunchedEffect(n.id) {
-        delay(POPUP_MS)
-        CarNotifications.dismissPopup(n.id)
-    }
-
-    Surface(
-        shape = RoundedCornerShape(20.dp),
-        color = MaterialTheme.colorScheme.surfaceContainerHigh,
-        contentColor = MaterialTheme.colorScheme.onSurface,
-        shadowElevation = 8.dp,
-        modifier = modifier
-            .padding(top = 8.dp)
-            .fillMaxWidth(0.7f)
-            .clickable { navigator.notifications() },
-    ) {
-        Row(
-            Modifier.padding(12.dp),
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(12.dp),
-        ) {
-            NotificationIcon(n)
-            Column(Modifier.weight(1f)) {
-                Text(n.appLabel, style = MaterialTheme.typography.labelMedium, maxLines = 1)
-                if (n.title.isNotBlank()) {
-                    Text(n.title, style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold, maxLines = 1, overflow = TextOverflow.Ellipsis)
-                }
-                if (n.text.isNotBlank()) {
-                    Text(n.text, style = MaterialTheme.typography.bodyMedium, maxLines = 2, overflow = TextOverflow.Ellipsis)
-                }
-            }
-            if (n.reply != null) {
-                FilledTonalButton(onClick = { navigator.notifications(replyTo = n.key) }) { Text("Reply") }
-            }
-            IconButton(onClick = { CarNotifications.dismissPopup(n.id) }) {
-                Icon(Icons.Filled.Close, contentDescription = "Dismiss")
-            }
-        }
-    }
-}
-
-private const val POPUP_MS = 8_000L

gearslip/src/main/java/app/seb3thehacker/gearslip/car/PhoneAppsScreen.kt

@@ -1,5 +1,6 @@
 package app.seb3thehacker.gearslip.car
 
+import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
@@ -14,7 +15,6 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
-import androidx.compose.material3.Button
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
@@ -53,6 +53,8 @@ fun PhoneAppsScreen() {
     }
 
     Column(Modifier.fillMaxSize().padding(horizontal = 20.dp, vertical = 12.dp)) {
+        ScreenHeader("Screen sharing")
+        Spacer(Modifier.height(12.dp))
         if (!TouchRelayService.enabled) {
             TouchRelayWarning()
             Spacer(Modifier.height(12.dp))
@@ -96,19 +98,18 @@ private fun TouchRelayWarning() {
                 style = MaterialTheme.typography.bodyMedium,
                 modifier = Modifier.weight(1f),
             )
-            Button(onClick = { PhoneApps.openAccessibilitySettings(context) }) { Text("Open") }
+            GsButton(onClick = { PhoneApps.openAccessibilitySettings(context) }) { Text("Open") }
         }
     }
 }
 
 @Composable
 private fun PhoneAppTile(app: PhoneApp, onClick: () -> Unit) {
-    Surface(
+    GsIconBox(
         onClick = onClick,
         modifier = Modifier.height(120.dp),
+        colors = GsColors(MaterialTheme.colorScheme.surfaceVariant, MaterialTheme.colorScheme.onSurfaceVariant),
         shape = MaterialTheme.shapes.extraLarge,
-        color = MaterialTheme.colorScheme.surfaceVariant,
-        contentColor = MaterialTheme.colorScheme.onSurfaceVariant,
     ) {
         Column(
             Modifier.fillMaxSize().padding(8.dp),

gearslip/src/main/java/app/seb3thehacker/gearslip/car/PhoneDialerScreen.kt

@@ -0,0 +1,397 @@
+package app.seb3thehacker.gearslip.car
+
+import app.seb3thehacker.gearslip.car.theme.*
+import android.Manifest
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.net.Uri
+import android.provider.ContactsContract
+import android.provider.Settings
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Call
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+
+/** A phone contact with at least one number, as read off the device's contacts. */
+internal data class Contact(val name: String, val number: String)
+
+private val CALL_PERMISSIONS = arrayOf(Manifest.permission.CALL_PHONE, Manifest.permission.READ_CONTACTS)
+
+/** Also used by [AssistantCommands] for "call <name>". */
+internal fun hasCallPermissions(context: Context): Boolean =
+    CALL_PERMISSIONS.all { context.checkSelfPermission(it) == PackageManager.PERMISSION_GRANTED }
+
+internal fun loadContacts(context: Context): List<Contact> {
+    if (context.checkSelfPermission(Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) return emptyList()
+    val out = mutableListOf<Contact>()
+    val projection = arrayOf(
+        ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME,
+        ContactsContract.CommonDataKinds.Phone.NUMBER,
+    )
+    context.contentResolver.query(
+        ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
+        projection, null, null,
+        "${ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME} ASC",
+    )?.use { cursor ->
+        val nameIndex = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME)
+        val numberIndex = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER)
+        while (cursor.moveToNext()) {
+            val name = cursor.getString(nameIndex) ?: continue
+            val number = cursor.getString(numberIndex) ?: continue
+            out += Contact(name, number)
+        }
+    }
+    return out.distinctBy { it.number }
+}
+
+internal fun placeCall(context: Context, number: String) {
+    if (number.isBlank()) return
+    if (context.checkSelfPermission(Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) return
+    runCatching {
+        context.startActivity(
+            Intent(Intent.ACTION_CALL, Uri.parse("tel:${Uri.encode(number)}")).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
+        )
+    }
+}
+
+/** A call another car screen wants to place - a number on a place page - waiting on the driver. */
+internal object CallPrompt {
+    val pending = kotlinx.coroutines.flow.MutableStateFlow<Contact?>(null)
+
+    fun ask(name: String, number: String) {
+        pending.value = Contact(name, number)
+    }
+}
+
+/** The dialer's own confirmation, drawn over the whole car screen for [CallPrompt]. */
+@Composable
+internal fun CallPromptOverlay() {
+    val context = LocalContext.current
+    val contact by CallPrompt.pending.collectAsState()
+    val c = contact ?: return
+    ConfirmCallOverlay(
+        c,
+        onConfirm = {
+            CallPrompt.pending.value = null
+            placeCall(context, c.number)
+        },
+        onDismiss = { CallPrompt.pending.value = null },
+    )
+}
+
+private const val TAB_CONTACTS = 0
+private const val TAB_KEYPAD = 1
+
+/** Dialing a number or calling a contact from the car screen: a contacts tab and a keypad tab. */
+@Composable
+fun PhoneDialerScreen() {
+    val context = LocalContext.current
+    val hasPermissions = hasCallPermissions(context)
+    var tab by remember { mutableStateOf(TAB_CONTACTS) }
+
+    Column(Modifier.fillMaxSize().padding(16.dp), verticalArrangement = Arrangement.spacedBy(16.dp)) {
+        // The tabs share the title's row, so the list and keypad get the height back.
+        ScreenHeader("Phone") {
+            if (hasPermissions) {
+                Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                    DialerTab("Contacts", tab == TAB_CONTACTS, Modifier.width(140.dp)) { tab = TAB_CONTACTS }
+                    DialerTab("Keypad", tab == TAB_KEYPAD, Modifier.width(140.dp)) { tab = TAB_KEYPAD }
+                }
+            }
+        }
+
+        if (!hasPermissions) {
+            MissingPermission(context)
+            return@Column
+        }
+
+        Box(Modifier.weight(1f).fillMaxWidth()) {
+            if (tab == TAB_CONTACTS) ContactsList(context) else Keypad(context)
+        }
+    }
+}
+
+@Composable
+private fun MissingPermission(context: Context) {
+    Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
+        Text(
+            "Gearslip needs the Phone and Contacts permissions to dial from here. Grant them " +
+                "from the app's settings.",
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+        GsButton(tone = GsTone.Tonal, onClick = {
+            context.startActivity(
+                Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", context.packageName, null)),
+            )
+        }) { Text("Open app settings") }
+    }
+}
+
+@Composable
+private fun DialerTab(label: String, selected: Boolean, modifier: Modifier, onClick: () -> Unit) {
+    GsIconBox(
+        onClick = onClick,
+        modifier = modifier.height(44.dp),
+        colors = if (selected) GsColors(MaterialTheme.colorScheme.primaryContainer, MaterialTheme.colorScheme.onPrimaryContainer)
+        else GsColors(MaterialTheme.colorScheme.surfaceContainerHigh, MaterialTheme.colorScheme.onSurface),
+        shape = MaterialTheme.shapes.large,
+        latched = selected,
+    ) {
+        Text(label, style = MaterialTheme.typography.titleMedium, fontWeight = if (selected) FontWeight.Bold else FontWeight.Normal)
+    }
+}
+
+/**
+ * A 3-column digit grid beside a fourth column holding backspace and call, stacked - four equal
+ * columns in all. Every row and both side buttons take an equal weighted share of whatever height
+ * is available, so this fits the car's short landscape frame without scrolling instead of
+ * overflowing off the bottom the way fixed-height rows did.
+ */
+@Composable
+private fun Keypad(context: Context) {
+    var number by remember { mutableStateOf("") }
+    val rows = listOf(
+        listOf("1", "2", "3"),
+        listOf("4", "5", "6"),
+        listOf("7", "8", "9"),
+        listOf("*", "0", "#"),
+    )
+
+    Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(12.dp)) {
+        Text(
+            number.ifEmpty { "Enter a number" },
+            style = MaterialTheme.typography.headlineSmall,
+            color = if (number.isEmpty()) MaterialTheme.colorScheme.onSurfaceVariant else MaterialTheme.colorScheme.onSurface,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.padding(vertical = 6.dp),
+        )
+        Row(Modifier.weight(1f).fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+            Column(Modifier.weight(3f).fillMaxHeight(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                rows.forEach { row ->
+                    Row(Modifier.weight(1f).fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                        row.forEach { digit ->
+                            KeypadButton(digit, Modifier.weight(1f).fillMaxHeight()) { number += digit }
+                        }
+                    }
+                }
+            }
+            Column(Modifier.weight(1f).fillMaxHeight(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                GsButton(
+                    onClick = { if (number.isNotEmpty()) number = number.dropLast(1) },
+                    tone = GsTone.Tonal,
+                    enabled = number.isNotEmpty(),
+                    modifier = Modifier.weight(1f).fillMaxWidth(),
+                ) { Text("⌫", style = MaterialTheme.typography.titleLarge) }
+                GsIconBox(
+                    onClick = { placeCall(context, number) },
+                    colors = gsColors(GsTone.Primary),
+                    enabled = number.isNotEmpty(),
+                    modifier = Modifier.weight(1f).fillMaxWidth(),
+                ) { Icon(Icons.Filled.Call, "Call") }
+            }
+        }
+    }
+}
+
+@Composable
+private fun KeypadButton(digit: String, modifier: Modifier, onClick: () -> Unit) {
+    GsIconBox(
+        onClick,
+        modifier,
+        colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHigh, MaterialTheme.colorScheme.onSurface),
+        shape = MaterialTheme.shapes.large,
+    ) {
+        Text(digit, style = MaterialTheme.typography.titleLarge)
+    }
+}
+
+@Composable
+private fun ContactsList(context: Context) {
+    val contacts by produceState(emptyList<Contact>(), context) {
+        value = withContext(Dispatchers.IO) { loadContacts(context) }
+    }
+    var query by remember { mutableStateOf("") }
+    var searching by remember { mutableStateOf(false) }
+    var pendingCall by remember { mutableStateOf<Contact?>(null) }
+
+    val filtered = remember(contacts, query) {
+        if (query.isBlank()) contacts
+        else contacts.filter { it.name.contains(query, ignoreCase = true) || it.number.contains(query) }
+    }
+
+    Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+        if (contacts.isNotEmpty()) {
+            ContactSearchField(query, searching, onToggle = { searching = !searching })
+        }
+        // The list (and its empty states) sit between the search field and the keyboard, never
+        // under either - the keyboard is docked at the bottom instead of jammed in right below
+        // the field, so results stay visible while typing rather than getting squeezed out.
+        Box(Modifier.weight(1f).fillMaxWidth()) {
+            when {
+                contacts.isEmpty() -> Text(
+                    "No contacts with a phone number found.",
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                filtered.isEmpty() -> Text(
+                    "No contacts match \"$query\".",
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                else -> LazyColumn(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                    items(filtered) { contact ->
+                        ContactRow(contact) { pendingCall = contact }
+                    }
+                }
+            }
+        }
+        if (searching) {
+            CarKeyboard(
+                query,
+                onTextChange = { query = it },
+                onSubmit = { searching = false },
+                onDismiss = { searching = false },
+            )
+        }
+    }
+
+    pendingCall?.let { contact ->
+        ConfirmCallOverlay(
+            contact = contact,
+            onConfirm = { placeCall(context, contact.number); pendingCall = null },
+            onDismiss = { pendingCall = null },
+        )
+    }
+}
+
+/**
+ * A plain Compose overlay, not [androidx.compose.material3.AlertDialog] - that opens a real
+ * Android Dialog/window, and this UI lives in a Presentation on a virtual display where a second
+ * window of the wrong type crashes outright ("Window type mismatch"). Every other popup in the
+ * car UI is drawn in-composition for the same reason; this just follows suit.
+ */
+@Composable
+private fun ConfirmCallOverlay(contact: Contact, onConfirm: () -> Unit, onDismiss: () -> Unit) {
+    Box(
+        Modifier.fillMaxSize().background(Color.Black.copy(alpha = 0.6f)).clickable(
+            indication = null,
+            interactionSource = remember { MutableInteractionSource() },
+            onClick = onDismiss,
+        ),
+        contentAlignment = Alignment.Center,
+    ) {
+        Surface(
+            onClick = {},
+            shape = MaterialTheme.shapes.extraLarge,
+            color = MaterialTheme.colorScheme.surfaceContainerHigh,
+            modifier = Modifier.fillMaxWidth(0.85f).padding(16.dp),
+        ) {
+            Column(
+                Modifier.padding(32.dp),
+                verticalArrangement = Arrangement.spacedBy(20.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+            ) {
+                Text("Call ${contact.name}?", style = MaterialTheme.typography.headlineSmall, fontWeight = FontWeight.Bold)
+                Text(contact.number, style = MaterialTheme.typography.titleLarge, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+                    GsButton(onClick = onDismiss, tone = GsTone.Outline, modifier = Modifier.weight(1f).height(56.dp)) {
+                        Text("Cancel", style = MaterialTheme.typography.titleMedium)
+                    }
+                    GsButton(onClick = onConfirm, modifier = Modifier.weight(1f).height(56.dp)) {
+                        Text("Call", style = MaterialTheme.typography.titleMedium)
+                    }
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun ContactSearchField(query: String, active: Boolean, onToggle: () -> Unit) {
+    Surface(
+        onClick = onToggle,
+        shape = MaterialTheme.shapes.large,
+        color = if (active) MaterialTheme.colorScheme.primaryContainer else MaterialTheme.colorScheme.surfaceContainerHigh,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Text(
+            query.ifEmpty { "Search contacts" },
+            style = MaterialTheme.typography.bodyLarge,
+            color = if (query.isEmpty()) MaterialTheme.colorScheme.onSurfaceVariant else MaterialTheme.colorScheme.onSurface,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 14.dp),
+        )
+    }
+}
+
+@Composable
+private fun ContactRow(contact: Contact, onClick: () -> Unit) {
+    Surface(
+        onClick = onClick,
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(
+            Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 12.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            Box(
+                Modifier.size(40.dp).background(MaterialTheme.colorScheme.primaryContainer, CircleShape),
+                contentAlignment = Alignment.Center,
+            ) {
+                Text(
+                    contact.name.take(1).uppercase(),
+                    style = MaterialTheme.typography.titleMedium,
+                    color = MaterialTheme.colorScheme.onPrimaryContainer,
+                    fontWeight = FontWeight.Bold,
+                )
+            }
+            Column(Modifier.weight(1f)) {
+                Text(contact.name, style = MaterialTheme.typography.titleMedium, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                Text(contact.number, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+            }
+            Icon(Icons.Filled.Call, contentDescription = "Call", tint = MaterialTheme.colorScheme.primary)
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/PhoneTyping.kt

@@ -0,0 +1,60 @@
+package app.seb3thehacker.gearslip.car
+
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/**
+ * The text field the car keyboard is typing into, shared with the phone so a passenger can type
+ * on the phone's own keyboard instead. Whichever [CarKeyboard] is on screen registers here; the
+ * phone app shows the same text while one is open, and its edits go back through the car field's
+ * own callbacks, so the car screen can't tell which keyboard typed.
+ */
+object PhoneTyping {
+
+    class Field internal constructor(
+        val id: Int,
+        val text: String,
+        internal val onTextChange: (String) -> Unit,
+        internal val onSubmit: () -> Unit,
+        internal val onDismiss: (() -> Unit)?,
+    )
+
+    private val fieldFlow = MutableStateFlow<Field?>(null)
+
+    /** The car's open field, or null when no car keyboard is showing. */
+    val field: StateFlow<Field?> = fieldFlow.asStateFlow()
+
+    private var nextId = 0
+
+    internal fun open(text: String, onTextChange: (String) -> Unit, onSubmit: () -> Unit, onDismiss: (() -> Unit)?): Int {
+        val id = ++nextId
+        fieldFlow.value = Field(id, text, onTextChange, onSubmit, onDismiss)
+        return id
+    }
+
+    /** The car field's text changed, from either keyboard. */
+    internal fun carText(id: Int, text: String) {
+        val f = fieldFlow.value ?: return
+        if (f.id == id && f.text != text) fieldFlow.value = Field(id, text, f.onTextChange, f.onSubmit, f.onDismiss)
+    }
+
+    internal fun close(id: Int) {
+        if (fieldFlow.value?.id == id) fieldFlow.value = null
+    }
+
+    /** From the phone: typed text goes to the car field as if typed there. */
+    fun type(text: String) {
+        fieldFlow.value?.onTextChange?.invoke(text)
+    }
+
+    fun submit() {
+        fieldFlow.value?.onSubmit?.invoke()
+    }
+
+    /** Closes the car keyboard where it can be closed; elsewhere only the phone's field goes. */
+    fun dismiss() {
+        val f = fieldFlow.value ?: return
+        f.onDismiss?.invoke() ?: close(f.id)
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/PlayerParts.kt

@@ -0,0 +1,254 @@
+package app.seb3thehacker.gearslip.car
+
+import android.media.session.PlaybackState
+import android.support.v4.media.session.PlaybackStateCompat
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.RowScope
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Favorite
+import androidx.compose.material.icons.filled.FavoriteBorder
+import androidx.compose.material.icons.filled.PlayArrow
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableLongStateOf
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.ImageBitmap
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.luminance
+import androidx.compose.animation.animateColorAsState
+import androidx.compose.animation.core.tween
+import app.seb3thehacker.gearslip.media.ArtColor
+import app.seb3thehacker.gearslip.media.MediaArt
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import androidx.core.graphics.drawable.toBitmap
+import app.seb3thehacker.gearslip.car.theme.GsIconBox
+import app.seb3thehacker.gearslip.car.theme.GsIconButton
+import app.seb3thehacker.gearslip.car.theme.GsSeekBar
+import app.seb3thehacker.gearslip.car.theme.GsTone
+import app.seb3thehacker.gearslip.car.theme.gsColors
+import app.seb3thehacker.gearslip.media.CarMedia
+import app.seb3thehacker.gearslip.media.CustomAction
+import app.seb3thehacker.gearslip.media.NowPlaying
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.withContext
+
+/*
+ * The pieces every player on the car screen is built from - the media screen, the column beside
+ * the map - so a button looks and behaves the same wherever it turns up.
+ */
+
+/** The seek bar, with elapsed and total time under it when [showTimes]. */
+@Composable
+internal fun PlayerProgress(now: NowPlaying, media: CarMedia, modifier: Modifier = Modifier, showTimes: Boolean = true) {
+    if (now.durationMs <= 0) return
+    var position by remember { mutableLongStateOf(now.currentPosition()) }
+    LaunchedEffect(now) {
+        while (true) {
+            position = now.currentPosition()
+            if (!now.playing) break
+            delay(500)
+        }
+    }
+    Column(modifier) {
+        GsSeekBar(
+            fraction = position.toFloat() / now.durationMs,
+            onSeek = { media.seek((it * now.durationMs).toLong()) },
+            enabled = now.canDo(PlaybackState.ACTION_SEEK_TO),
+            modifier = Modifier.fillMaxWidth().padding(vertical = 4.dp),
+        )
+        if (showTimes) {
+            Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceBetween) {
+                Text(formatDuration(position), style = MaterialTheme.typography.labelMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                Text(formatDuration(now.durationMs), style = MaterialTheme.typography.labelMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+            }
+        }
+    }
+}
+
+/** "1:05" for under a minute past the hour, "1:01:05" once an hour is involved. */
+internal fun formatDuration(ms: Long): String {
+    val totalSeconds = (ms / 1000).coerceAtLeast(0)
+    val hours = totalSeconds / 3600
+    val minutes = (totalSeconds % 3600) / 60
+    val seconds = totalSeconds % 60
+    return if (hours > 0) "%d:%02d:%02d".format(hours, minutes, seconds) else "%d:%02d".format(minutes, seconds)
+}
+
+/** Previous, play/pause, next. [skip] sizes the outer two; play is a step bigger. */
+@Composable
+internal fun TransportRow(now: NowPlaying, media: CarMedia, skip: Dp, modifier: Modifier = Modifier) {
+    val play = skip * 1.25f
+    Row(modifier, horizontalArrangement = Arrangement.SpaceEvenly, verticalAlignment = Alignment.CenterVertically) {
+        GsIconButton(
+            MediaIcons.Previous, "Previous", media::previous,
+            enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_PREVIOUS), size = skip, iconSize = skip * 0.58f, shape = CircleShape,
+        )
+        GsIconButton(
+            if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow,
+            if (now.playing) "Pause" else "Play",
+            media::togglePlay,
+            tone = GsTone.Primary, size = play, iconSize = play * 0.58f, shape = CircleShape,
+        )
+        GsIconButton(
+            MediaIcons.Next, "Next", media::next,
+            enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_NEXT), size = skip, iconSize = skip * 0.58f, shape = CircleShape,
+        )
+    }
+}
+
+/**
+ * Like, shuffle and repeat, then up to [maxOther] of the app's other buttons, all icon-only. One
+ * the app doesn't support stays on screen greyed out, so the row never shifts between apps.
+ * [trailing] adds buttons of the caller's own at the end (the side column's lyrics button).
+ */
+@Composable
+internal fun PlayModeRow(
+    now: NowPlaying,
+    media: CarMedia,
+    size: Dp,
+    modifier: Modifier = Modifier,
+    maxOther: Int = 0,
+    trailing: @Composable RowScope.() -> Unit = {},
+) {
+    val modes by media.modes.collectAsState()
+    val liked = now.liked
+    val shuffleKnown = modes.shuffle != PlaybackStateCompat.SHUFFLE_MODE_INVALID
+    val repeatKnown = modes.repeat != PlaybackStateCompat.REPEAT_MODE_INVALID
+    val shuffleOn = shuffleKnown && modes.shuffle != PlaybackStateCompat.SHUFFLE_MODE_NONE
+    val repeatOn = repeatKnown && modes.repeat != PlaybackStateCompat.REPEAT_MODE_NONE
+    val icon = size * 0.52f
+    Row(modifier, horizontalArrangement = Arrangement.SpaceEvenly, verticalAlignment = Alignment.CenterVertically) {
+        // An app's own like, shuffle or repeat button shows whether it's on only through its icon,
+        // so that icon is drawn, as Android Auto does, and lit when its name says it's on.
+        // Gearslip's own stand in for apps that report a heart rating or shuffle and repeat modes.
+        val likeAction = now.likeAction
+        if (likeAction != null) {
+            CustomActionButton(likeAction, media, size, toggle = true)
+        } else {
+            GsIconButton(
+                if (liked == true) Icons.Filled.Favorite else Icons.Filled.FavoriteBorder,
+                if (liked == true) "Unlike" else "Like",
+                media::toggleLike,
+                enabled = liked != null,
+                tone = if (liked == true) GsTone.Primary else GsTone.Neutral,
+                size = size, iconSize = icon,
+            )
+        }
+        val shuffleAction = now.shuffleAction
+        if (shuffleAction != null) {
+            CustomActionButton(shuffleAction, media, size, toggle = true)
+        } else {
+            GsIconButton(
+                MediaIcons.Shuffle, if (shuffleOn) "Shuffle off" else "Shuffle on",
+                media::toggleShuffle,
+                enabled = shuffleKnown,
+                tone = if (shuffleOn) GsTone.Primary else GsTone.Neutral,
+                size = size, iconSize = icon,
+            )
+        }
+        val repeatAction = now.repeatAction
+        if (repeatAction != null) {
+            CustomActionButton(repeatAction, media, size, toggle = true)
+        } else {
+            GsIconButton(
+                if (modes.repeat == PlaybackStateCompat.REPEAT_MODE_ONE) MediaIcons.RepeatOne else MediaIcons.Repeat,
+                "Repeat",
+                media::cycleRepeat,
+                enabled = repeatKnown,
+                tone = if (repeatOn) GsTone.Primary else GsTone.Neutral,
+                size = size, iconSize = icon,
+            )
+        }
+        now.otherActions.take(maxOther).forEach { CustomActionButton(it, media, size) }
+        trailing()
+    }
+}
+
+/**
+ * One of the app's own buttons, drawn with the app's own icon - it lives in the app's package,
+ * not Gearslip's, so it's loaded from there. Its name stands in if the icon won't load.
+ */
+@Composable
+private fun CustomActionButton(action: CustomAction, media: CarMedia, size: Dp, toggle: Boolean = false) {
+    val icon = rememberActionIcon(action)
+    GsIconBox(
+        onClick = { media.custom(action) },
+        modifier = Modifier.size(size),
+        colors = gsColors(if (toggle && action.on) GsTone.Primary else GsTone.Neutral),
+    ) {
+        if (icon != null) {
+            Icon(icon, action.name, Modifier.size(size * 0.52f))
+        } else {
+            Text(action.name, style = MaterialTheme.typography.labelSmall, maxLines = 2, overflow = TextOverflow.Ellipsis)
+        }
+    }
+}
+
+@Composable
+private fun rememberActionIcon(action: CustomAction): ImageBitmap? {
+    val context = LocalContext.current
+    val app by CarServices.mediaApp.collectAsState()
+    val pkg = app?.component?.packageName
+    val icon by produceState<ImageBitmap?>(null, pkg, action.icon) {
+        value = if (pkg == null || action.icon == 0) null else withContext(Dispatchers.IO) {
+            runCatching {
+                context.packageManager.getResourcesForApplication(pkg)
+                    .getDrawable(action.icon, null).toBitmap(96, 96).asImageBitmap()
+            }.getOrNull()
+        }
+    }
+    return icon
+}
+
+/** The track's art, from the session's bitmap or, failing that, its art URI. */
+@Composable
+internal fun rememberArt(now: NowPlaying): android.graphics.Bitmap? {
+    val context = LocalContext.current
+    val art by produceState(now.art, now.art, now.artUri) { value = now.art ?: MediaArt.load(context, now.artUri) }
+    return art
+}
+
+/**
+ * A background taken from the album art's main colour, in place of [fallback]. Only the hue and a
+ * capped amount of its saturation come from the art; the lightness stays close to the theme's
+ * own ([darkLightness] or [lightLightness]), so text drawn in the theme's colours reads the same
+ * on any cover. Art with no real colour in it keeps [fallback]. Fades between songs rather than
+ * jumping.
+ */
+@Composable
+internal fun rememberArtColor(
+    art: android.graphics.Bitmap?,
+    fallback: Color,
+    darkLightness: Float = 0.2f,
+    lightLightness: Float = 0.86f,
+): Color {
+    val dark = fallback.luminance() < 0.5f
+    val tint by produceState<ArtColor.Tint?>(null, art) {
+        value = art?.let { withContext(Dispatchers.Default) { runCatching { ArtColor.of(it) }.getOrNull() } }
+    }
+    val target = tint?.let {
+        if (dark) Color.hsl(it.hue, it.saturation.coerceIn(0.3f, 0.5f), darkLightness)
+        else Color.hsl(it.hue, it.saturation.coerceIn(0.35f, 0.55f), lightLightness)
+    } ?: fallback
+    return animateColorAsState(target, tween(600), label = "art colour").value
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/Prefetch.kt

@@ -1,13 +1,15 @@
 package app.seb3thehacker.gearslip.car
 
 import android.content.Context
+import app.seb3thehacker.gearslip.CertProvider
 import app.seb3thehacker.gearslip.GearslipLog
 import app.seb3thehacker.gearslip.mirror.PhoneApps
 import java.util.concurrent.Executors
 
 /**
  * Loads what the car screens show before anyone opens them: the car and media apps with their
- * icons, the phone's launcher apps, the weather and the calendar. Each screen paints from these
+ * icons, the phone's launcher apps, the weather and the calendar. Also unlocks the certificate,
+ * so a head unit's first message is answered at once. Each screen paints from these
  * results at once and refreshes behind them, so nothing waits on the package manager, the
  * network or the calendar provider.
  *
@@ -28,6 +30,7 @@ object Prefetch {
         val app = context.applicationContext
         worker.execute {
             val start = System.currentTimeMillis()
+            step("certificate") { CertProvider.warm(app) }
             step("launcher apps") { warmLauncherApps(app) }
             step("phone apps") { PhoneApps.warm(app) }
             step("weather and calendar") { warmDashboard(app) }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/ScreenHeader.kt

@@ -0,0 +1,43 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.RowScope
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.car.theme.GsIconButton
+
+/**
+ * The top of every screen reached from Home: a back button in the current theme, the title, and
+ * room on the right for the screen's own controls. A car touchscreen has no hardware back button,
+ * so this is the way out of a screen.
+ */
+@Composable
+fun ScreenHeader(title: String, modifier: Modifier = Modifier, trailing: @Composable RowScope.() -> Unit = {}) {
+    val navigator = LocalCarNavigator.current
+    Row(
+        modifier.fillMaxWidth(),
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        GsIconButton(Icons.AutoMirrored.Filled.ArrowBack, "Back", navigator::back)
+        Text(
+            title,
+            style = MaterialTheme.typography.headlineSmall,
+            fontWeight = FontWeight.Bold,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.weight(1f),
+        )
+        trailing()
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/TemplateChrome.kt

@@ -1,6 +1,9 @@
 package app.seb3thehacker.gearslip.car
 
+import app.seb3thehacker.gearslip.car.theme.*
 import android.graphics.Rect
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -13,28 +16,42 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.KeyboardArrowUp
+import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.collectAsState
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.draw.rotate
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import androidx.car.app.model.CarIcon
 import androidx.car.app.model.Template
 import androidx.car.app.model.PlaceListMapTemplate
+import androidx.car.app.navigation.model.Lane
+import androidx.car.app.navigation.model.LaneDirection
 import androidx.car.app.navigation.model.MapTemplate
 import androidx.car.app.navigation.model.MapWithContentTemplate
 import androidx.car.app.navigation.model.NavigationTemplate
 import androidx.car.app.navigation.model.PlaceListNavigationTemplate
 import androidx.car.app.navigation.model.RoutePreviewNavigationTemplate
 import androidx.car.app.navigation.model.RoutingInfo
+import androidx.car.app.navigation.model.Step
 import androidx.car.app.navigation.model.TravelEstimate
+import app.seb3thehacker.gearslip.host.clockTime
 import app.seb3thehacker.gearslip.host.color
+import app.seb3thehacker.gearslip.host.image
 import app.seb3thehacker.gearslip.host.display
 import app.seb3thehacker.gearslip.host.remainingTime
 import app.seb3thehacker.gearslip.host.text
@@ -96,7 +113,7 @@ private fun NavigationChrome(template: NavigationTemplate, modifier: Modifier) {
             Modifier.align(Alignment.TopEnd).padding(12.dp),
         )
         if (!pan) template.destinationTravelEstimate?.let {
-            TravelEstimateBar(it, Modifier.align(Alignment.BottomStart))
+            TravelEstimateBar(it, Modifier.align(Alignment.BottomStart).padding(12.dp))
         }
     }
 }
@@ -106,7 +123,7 @@ private fun NavigationChrome(template: NavigationTemplate, modifier: Modifier) {
 private fun RoutingCard(info: RoutingInfo, modifier: Modifier = Modifier) {
     if (info.isLoading) {
         ChromeSurface(modifier) {
-            Text("Finding a route…", Modifier.padding(16.dp), style = MaterialTheme.typography.titleMedium)
+            Text("Finding a route…", Modifier.padding(16.dp), style = ChromeType.title)
         }
         return
     }
@@ -120,89 +137,168 @@ private fun RoutingCard(info: RoutingInfo, modifier: Modifier = Modifier) {
                 Column(Modifier.weight(1f)) {
                     val distance = info.currentDistance.display()
                     if (distance.isNotEmpty()) {
-                        Text(
-                            distance,
-                            style = MaterialTheme.typography.headlineSmall,
-                            fontWeight = FontWeight.Bold,
-                        )
+                        Text(distance, style = ChromeType.headline)
                     }
-                    Text(
-                        step.cue.text(),
-                        style = MaterialTheme.typography.titleMedium,
-                        maxLines = 2,
-                        overflow = TextOverflow.Ellipsis,
-                    )
+                    Text(step.cue.text(), style = ChromeType.title, maxLines = 2, overflow = TextOverflow.Ellipsis)
                 }
             }
             val road = step.road.text()
             if (road.isNotEmpty()) {
                 Text(
                     road,
-                    style = MaterialTheme.typography.bodyMedium,
+                    style = ChromeType.body,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
                 )
             }
+            // Neither is sent by every app - most say only "turn left" and trust the driver to
+            // find the lane themselves - so both are drawn only when there is something to draw.
+            info.junctionImage?.let { junction ->
+                Spacer(Modifier.height(10.dp))
+                JunctionImage(junction)
+            }
+            LaneGuidance(step, Modifier.padding(top = 10.dp))
             info.nextStep?.let { next ->
                 Spacer(Modifier.height(8.dp))
                 Row(verticalAlignment = Alignment.CenterVertically) {
-                    Text(
-                        "then",
-                        style = MaterialTheme.typography.labelMedium,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    )
+                    Text("then", style = ChromeType.label, color = MaterialTheme.colorScheme.onSurfaceVariant)
                     Spacer(Modifier.width(8.dp))
                     CarGlyph(next.maneuver?.icon, Modifier.size(20.dp))
                     Spacer(Modifier.width(8.dp))
-                    Text(
-                        next.cue.text(),
-                        style = MaterialTheme.typography.bodyMedium,
-                        maxLines = 1,
-                        overflow = TextOverflow.Ellipsis,
-                    )
+                    Text(next.cue.text(), style = ChromeType.body, maxLines = 1, overflow = TextOverflow.Ellipsis)
                 }
             }
         }
     }
 }
 
-/** Time and distance left, along the bottom where it stays out of the map's way. */
+/** The zoomed-in intersection an app draws for a junction too complex for an arrow to explain. */
+@Composable
+private fun JunctionImage(icon: CarIcon, modifier: Modifier = Modifier) {
+    val bitmap = icon.image(LocalContext.current) ?: return
+    Image(
+        bitmap,
+        contentDescription = null,
+        contentScale = ContentScale.Fit,
+        modifier = modifier.fillMaxWidth().heightIn(max = 120.dp),
+    )
+}
+
+/**
+ * Which lane to be in before the manoeuvre, either as the app's own picture ([Step.getLanesImage])
+ * or as a row of arrows built from its structured lane data - whichever it sent. The recommended
+ * lane, or lanes, stand out in the theme's own colour; the rest sit on the same muted, solid tile
+ * everything else uses, never dimmed by transparency.
+ */
+@Composable
+private fun LaneGuidance(step: Step, modifier: Modifier = Modifier) {
+    step.lanesImage?.let {
+        JunctionImage(it, modifier)
+        return
+    }
+    val lanes = step.lanes.orEmpty()
+    if (lanes.isEmpty()) return
+    Row(modifier, horizontalArrangement = Arrangement.spacedBy(6.dp)) {
+        lanes.forEach { lane -> LaneTile(lane) }
+    }
+}
+
+@Composable
+private fun LaneTile(lane: Lane) {
+    val directions = lane.directions.orEmpty()
+    val shown = directions.firstOrNull { it.isRecommended } ?: directions.firstOrNull()
+    val recommended = shown?.isRecommended == true
+    Box(
+        Modifier
+            .size(36.dp)
+            .clip(RoundedCornerShape(8.dp))
+            .background(
+                if (recommended) MaterialTheme.colorScheme.primaryContainer
+                else MaterialTheme.colorScheme.surfaceContainerHighest,
+            ),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            Icons.Filled.KeyboardArrowUp,
+            contentDescription = if (recommended) "Recommended lane" else "Lane",
+            tint = if (recommended) MaterialTheme.colorScheme.onPrimaryContainer
+            else MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(24.dp).rotate(shown.turnDegrees()),
+        )
+    }
+}
+
+/** The one arrow glyph this app draws, turned to stand in for every shape a lane can permit. */
+private fun LaneDirection?.turnDegrees(): Float = when (this?.shape) {
+    LaneDirection.SHAPE_SLIGHT_RIGHT -> 30f
+    LaneDirection.SHAPE_NORMAL_RIGHT -> 90f
+    LaneDirection.SHAPE_SHARP_RIGHT -> 135f
+    LaneDirection.SHAPE_U_TURN_RIGHT -> 170f
+    LaneDirection.SHAPE_SLIGHT_LEFT -> -30f
+    LaneDirection.SHAPE_NORMAL_LEFT -> -90f
+    LaneDirection.SHAPE_SHARP_LEFT -> -135f
+    LaneDirection.SHAPE_U_TURN_LEFT -> -170f
+    else -> 0f
+}
+
+/**
+ * The trip at a glance: time and distance left, the clock time it ends at, and - beside them,
+ * where a thumb reaches - the app's own way to stop navigating. A floating card rather than a
+ * full-width bar, so it reads as one thing beside the manoeuvre card above it instead of a strip
+ * that happens to hold three numbers. The close button is Gearslip's own, not the app's: an
+ * actionStrip's actions carry no flag saying which one (if any) means "stop navigating" - the
+ * first button here turned out to be a mute toggle, not an exit - so this leaves the app the way
+ * going Home already does, rather than guess at the app's own controls and risk getting it wrong.
+ */
 @Composable
 private fun TravelEstimateBar(estimate: TravelEstimate, modifier: Modifier = Modifier) {
-    val dark = MaterialTheme.colorScheme.surface.luminanceIsDark()
     val time = remainingTime(estimate.remainingTimeSeconds)
     val distance = estimate.remainingDistance.display()
+    val arrival = estimate.arrivalTimeAtDestination.clockTime()
     val trip = estimate.tripText.text()
-    if (time.isEmpty() && distance.isEmpty() && trip.isEmpty()) return
+    if (time.isEmpty() && distance.isEmpty() && arrival.isEmpty() && trip.isEmpty()) return
 
-    Surface(
-        color = Color.Black.copy(alpha = 0.6f),
-        contentColor = Color.White,
-        modifier = modifier.fillMaxWidth(),
-    ) {
+    val detail = listOfNotNull(
+        arrival.takeIf { it.isNotEmpty() },
+        distance.takeIf { it.isNotEmpty() },
+        trip.takeIf { it.isNotEmpty() },
+    ).joinToString("  •  ")
+
+    // The same solid card the manoeuvre card above it uses - one surface for the whole map
+    // chrome, rather than this one spot styled on its own as a bar over the map.
+    ChromeSurface(modifier, shadowElevation = 8.dp) {
+        val dark = MaterialTheme.colorScheme.surface.luminanceIsDark()
         Row(
-            Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
+            Modifier.padding(start = 8.dp, end = 18.dp, top = 10.dp, bottom = 10.dp),
             verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(20.dp),
         ) {
-            if (time.isNotEmpty()) {
-                Text(
-                    time,
-                    style = MaterialTheme.typography.titleLarge,
-                    fontWeight = FontWeight.Bold,
-                    color = estimate.remainingTimeColor.color(dark, Color.White),
-                )
-            }
-            if (distance.isNotEmpty()) {
-                Text(
-                    distance,
-                    style = MaterialTheme.typography.titleMedium,
-                    color = estimate.remainingDistanceColor.color(dark, Color.White),
-                )
-            }
-            if (trip.isNotEmpty()) {
-                Text(trip, style = MaterialTheme.typography.bodyMedium, maxLines = 1)
+            // Not a disconnect: the connection stays up and the app decides its own next screen.
+            // Ending navigation is its own call, separate from a back press - a back press only
+            // pops the on-screen card, leaving the app still believing it is navigating (so a
+            // freshly picked destination silently does nothing); this is the call that actually
+            // clears that flag on the app's side.
+            GsIconButton(
+                Icons.Filled.Close,
+                "Stop navigating",
+                { CarServices.nav.stopNavigating() },
+                colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHighest, MaterialTheme.colorScheme.onSurface),
+                size = 40.dp,
+                iconSize = 20.dp,
+                shape = CircleShape,
+            )
+            Spacer(Modifier.width(10.dp))
+            Column {
+                if (time.isNotEmpty()) {
+                    Text(
+                        time,
+                        style = ChromeType.headline,
+                        color = estimate.remainingTimeColor.color(dark, MaterialTheme.colorScheme.onSurface),
+                    )
+                }
+                if (detail.isNotEmpty()) {
+                    Text(detail, style = ChromeType.body, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                }
             }
         }
     }
@@ -258,7 +354,10 @@ private fun MapWithContentChrome(template: MapWithContentTemplate, modifier: Mod
         template.mapController?.mapActionStrip,
         fullHeight = template.contentTemplate.needsFullHeight(),
     ) {
-        ContentTemplate(template.contentTemplate, Modifier)
+        // A pane floating over the map is a place or a route the app is proposing, so its one
+        // action - Start - counts itself down rather than waiting to be pressed; the same pane
+        // filling a whole screen elsewhere gets no such push.
+        ContentTemplate(template.contentTemplate, Modifier, autoStartPane = true)
     }
 }
 
@@ -276,7 +375,7 @@ private fun MapChrome(template: MapTemplate, modifier: Modifier) {
                     template.header?.startHeaderAction,
                     template.header?.endHeaderActions.orEmpty(),
                 )
-                if (template.pane != null) PaneRows(template.pane)
+                if (template.pane != null) PaneRows(template.pane, autoStart = true)
                 else ItemListColumn(template.itemList)
             }
         }
@@ -322,13 +421,13 @@ private fun RoutePreviewChrome(template: RoutePreviewNavigationTemplate, modifie
                 )
                 Box(Modifier.weight(1f, fill = false)) {
                     if (template.isLoading) {
-                        Text("Finding routes…", Modifier.padding(14.dp))
+                        Text("Finding routes…", Modifier.padding(14.dp), style = ChromeType.title)
                     } else {
                         ItemListColumn(template.itemList)
                     }
                 }
                 template.navigateAction?.let {
-                    ActionRow(listOf(it), Modifier.padding(12.dp))
+                    AutoStartButton(it, Modifier.padding(12.dp))
                 }
             }
         }
@@ -346,7 +445,7 @@ private fun ListPane(
     ChromeSurface(modifier, shape = androidx.compose.foundation.shape.RoundedCornerShape(0.dp)) {
         Column {
             HeaderBar(title, startAction)
-            if (loading) Text("Loading…", Modifier.padding(14.dp))
+            if (loading) Text("Loading…", Modifier.padding(14.dp), style = ChromeType.title)
             else ItemListColumn(itemList)
         }
     }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/TemplateContent.kt

@@ -1,9 +1,12 @@
 package app.seb3thehacker.gearslip.car
 
-import androidx.compose.foundation.clickable
+import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.Search
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
@@ -12,6 +15,7 @@ import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
@@ -20,6 +24,7 @@ import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -27,8 +32,10 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import androidx.car.app.model.GridItem
 import androidx.car.app.model.GridTemplate
 import androidx.car.app.model.Item
 import androidx.car.app.model.ItemList
@@ -38,6 +45,7 @@ import androidx.car.app.model.MessageTemplate
 import androidx.car.app.model.PaneTemplate
 import androidx.car.app.model.Row as CarRow
 import androidx.car.app.model.SearchTemplate
+import androidx.compose.foundation.clickable
 import androidx.car.app.model.Section
 import androidx.car.app.model.SectionedItemTemplate
 import androidx.car.app.model.TabTemplate
@@ -51,6 +59,7 @@ import androidx.car.app.media.model.MediaPlaybackTemplate
 import androidx.car.app.OnDoneCallback
 import androidx.car.app.serialization.Bundleable
 import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.host.isDrawable
 import app.seb3thehacker.gearslip.host.inputChanged
 import app.seb3thehacker.gearslip.host.inputSubmitted
 import app.seb3thehacker.gearslip.host.submitted
@@ -65,18 +74,24 @@ import app.seb3thehacker.gearslip.host.textChanged
  * the same function either way - the only difference is how much room they get.
  */
 @Composable
-fun ContentTemplate(template: Template?, modifier: Modifier = Modifier) {
+fun ContentTemplate(
+    template: Template?,
+    modifier: Modifier = Modifier,
+    autoStartPane: Boolean = false,
+    ownActionsElsewhere: Boolean = false,
+    tabId: String = "",
+) {
     when (template) {
         null -> Unit
         is ListTemplate -> ListContent(template, modifier)
         is GridTemplate -> GridContent(template, modifier)
-        is PaneTemplate -> PaneContent(template, modifier)
+        is PaneTemplate -> PaneContent(template, modifier, autoStartPane)
         is MessageTemplate -> MessageContent(template, modifier)
         is LongMessageTemplate -> LongMessageContent(template, modifier)
         is SearchTemplate -> SearchContent(template, modifier)
         is SignInTemplate -> SignInContent(template, modifier)
         is TabTemplate -> TabContent(template, modifier)
-        is SectionedItemTemplate -> SectionedContent(template, modifier)
+        is SectionedItemTemplate -> SectionedContent(template, modifier, showActionsInHeader = !ownActionsElsewhere, tabId = tabId)
         is MediaPlaybackTemplate -> MediaPlaybackContent(template, modifier)
         else -> UnsupportedChrome(template, modifier)
     }
@@ -126,7 +141,7 @@ private fun GridContent(template: GridTemplate, modifier: Modifier) {
 }
 
 @Composable
-private fun PaneContent(template: PaneTemplate, modifier: Modifier) {
+private fun PaneContent(template: PaneTemplate, modifier: Modifier, autoStart: Boolean = false) {
     ContentSurface(modifier) {
         HeaderBar(
             headerTitle(template.header, template.title.text()),
@@ -134,7 +149,7 @@ private fun PaneContent(template: PaneTemplate, modifier: Modifier) {
             template.header?.endHeaderActions.orEmpty(),
             template.actionStrip,
         )
-        if (template.pane?.isLoading == true) Loading() else PaneRows(template.pane)
+        if (template.pane?.isLoading == true) Loading() else PaneRows(template.pane, autoStart = autoStart)
     }
 }
 
@@ -143,27 +158,45 @@ private fun PaneContent(template: PaneTemplate, modifier: Modifier) {
 @Composable
 private fun MessageContent(template: MessageTemplate, modifier: Modifier) {
     ContentSurface(modifier) {
-        HeaderBar(
-            headerTitle(template.header, template.title.text()),
-            template.header?.startHeaderAction ?: template.headerAction,
-            template.header?.endHeaderActions.orEmpty(),
-            template.actionStrip,
-        )
+        // The header carries only the back arrow, not a title - a message template's own title
+        // is usually the long-form question ("Would you like to download the map...") that
+        // reads fine centred in the body but doesn't fit a one-line header without truncating.
+        val backAction = template.header?.startHeaderAction ?: template.headerAction
+        HeaderBar("", backAction, template.header?.endHeaderActions.orEmpty(), template.actionStrip)
         if (template.isLoading) {
             Loading()
             return@ContentSurface
         }
-        Row(
-            Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
-            verticalAlignment = Alignment.CenterVertically,
+        // A back arrow already undoes this screen, so an app's own "Cancel" button would just
+        // be a second way to do the one thing the header already offers.
+        val actions = template.actions.orEmpty().filter { it.isDrawable() }.let { list ->
+            if (backAction != null) list.filterNot { it.title.text().equals("Cancel", ignoreCase = true) } else list
+        }
+        Column(
+            Modifier.weight(1f).fillMaxWidth().padding(24.dp),
+            verticalArrangement = Arrangement.Center,
+            horizontalAlignment = Alignment.CenterHorizontally,
         ) {
             template.icon?.let {
-                CarGlyph(it, Modifier.size(32.dp))
-                Spacer(Modifier.width(12.dp))
+                CarGlyph(it, Modifier.size(40.dp))
+                Spacer(Modifier.height(12.dp))
+            }
+            Text(template.title.text(), style = ChromeType.title, textAlign = TextAlign.Center)
+            val detail = template.message.text()
+            if (detail.isNotEmpty()) {
+                Spacer(Modifier.height(8.dp))
+                Text(
+                    detail,
+                    style = ChromeType.body,
+                    textAlign = TextAlign.Center,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+            if (actions.isNotEmpty()) {
+                Spacer(Modifier.height(24.dp))
+                ActionRow(actions, Modifier.fillMaxWidth(0.6f), large = true)
             }
-            Text(template.message.text(), style = MaterialTheme.typography.bodyLarge)
         }
-        ActionRow(template.actions.orEmpty(), Modifier.padding(16.dp))
     }
 }
 
@@ -181,7 +214,7 @@ private fun LongMessageContent(template: LongMessageTemplate, modifier: Modifier
         )
         Text(
             template.message.text(),
-            style = MaterialTheme.typography.bodyMedium,
+            style = ChromeType.body,
             modifier = Modifier
                 .weight(1f)
                 .verticalScroll(rememberScrollState())
@@ -206,6 +239,9 @@ private fun SearchContent(template: SearchTemplate, modifier: Modifier) {
     // initialSearchText would fight whatever is being typed.
     var query by remember { mutableStateOf(template.initialSearchText.orEmpty()) }
     val delegate = template.searchCallbackDelegate
+    // An app that opens on results ("navigate to Starbucks") asks for the keyboard to stay down,
+    // so the results aren't hidden under it. Tapping the field brings it up.
+    var typing by remember { mutableStateOf(template.isShowKeyboardByDefault) }
 
     ContentSurface(modifier) {
         // Back button and field share a row: on a 480px screen the keyboard and the results
@@ -216,7 +252,15 @@ private fun SearchContent(template: SearchTemplate, modifier: Modifier) {
             horizontalArrangement = Arrangement.spacedBy(8.dp),
         ) {
             template.headerAction?.let { ActionButton(it) }
-            SearchField(query, template.searchHint.orEmpty(), Modifier.weight(1f))
+            SearchField(
+                query,
+                template.searchHint.orEmpty(),
+                Modifier.weight(1f).clickable { typing = true },
+                onClear = {
+                    query = ""
+                    delegate.textChanged("")
+                },
+            )
             ActionRow(template.actionStrip?.actions.orEmpty())
         }
 
@@ -225,33 +269,73 @@ private fun SearchContent(template: SearchTemplate, modifier: Modifier) {
             else ItemListColumn(template.itemList, modifier = Modifier.fillMaxSize())
         }
 
-        CarKeyboard(
-            text = query,
-            onTextChange = {
-                query = it
-                delegate.textChanged(it)
-            },
-            onSubmit = { delegate.submitted(query) },
-        )
+        if (typing) {
+            CarKeyboard(
+                text = query,
+                onTextChange = {
+                    query = it
+                    delegate.textChanged(it)
+                },
+                onSubmit = { delegate.submitted(query) },
+                onDismiss = { typing = false },
+            )
+        }
     }
 }
 
+/**
+ * The field the on-screen keyboard types into. It is the same height and shape as the round
+ * buttons beside it, so the header reads as one row of controls rather than a thin strip squeezed
+ * between two big buttons, and it carries a magnifier so it reads as search at a glance.
+ * [onClear] adds a clear button once something is typed; [searchIcon] is off for sign-in fields.
+ */
 @Composable
-private fun SearchField(query: String, hint: String, modifier: Modifier = Modifier) {
+internal fun SearchField(
+    query: String,
+    hint: String,
+    modifier: Modifier = Modifier,
+    searchIcon: Boolean = true,
+    onClear: (() -> Unit)? = null,
+) {
+    val muted = MaterialTheme.colorScheme.onSurfaceVariant
     Surface(
         color = MaterialTheme.colorScheme.surfaceContainerHighest,
-        shape = RoundedCornerShape(10.dp),
-        modifier = modifier.fillMaxWidth(),
+        shape = androidx.compose.foundation.shape.CircleShape,
+        modifier = modifier.fillMaxWidth().height(ICON_BUTTON_SIZE),
     ) {
-        Text(
-            query.ifEmpty { hint.ifEmpty { "Search" } },
-            style = MaterialTheme.typography.titleMedium,
-            color = if (query.isEmpty()) MaterialTheme.colorScheme.onSurfaceVariant
-            else MaterialTheme.colorScheme.onSurface,
-            maxLines = 1,
-            overflow = TextOverflow.Ellipsis,
-            modifier = Modifier.padding(horizontal = 14.dp, vertical = 8.dp),
-        )
+        Row(
+            Modifier.padding(start = if (searchIcon) 16.dp else 22.dp, end = 6.dp),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            if (searchIcon) {
+                androidx.compose.material3.Icon(
+                    androidx.compose.material.icons.Icons.Filled.Search,
+                    contentDescription = null,
+                    tint = muted,
+                    modifier = Modifier.size(26.dp),
+                )
+                Spacer(Modifier.width(12.dp))
+            }
+            Text(
+                query.ifEmpty { hint.ifEmpty { "Search" } },
+                style = MaterialTheme.typography.titleMedium,
+                color = if (query.isEmpty()) muted else MaterialTheme.colorScheme.onSurface,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = Modifier.weight(1f),
+            )
+            if (onClear != null && query.isNotEmpty()) {
+                GsIconButton(
+                    androidx.compose.material.icons.Icons.Filled.Close,
+                    "Clear",
+                    onClear,
+                    colors = GsColors(androidx.compose.ui.graphics.Color.Transparent, muted),
+                    size = 42.dp,
+                    iconSize = 22.dp,
+                    shape = androidx.compose.foundation.shape.CircleShape,
+                )
+            }
+        }
     }
 }
 
@@ -279,7 +363,7 @@ private fun SignInContent(template: SignInTemplate, modifier: Modifier) {
         if (instructions.isNotEmpty()) {
             Text(
                 instructions,
-                style = MaterialTheme.typography.bodyLarge,
+                style = ChromeType.body,
                 modifier = Modifier.padding(horizontal = 16.dp, vertical = 6.dp),
             )
         }
@@ -298,7 +382,7 @@ private fun SignInContent(template: SignInTemplate, modifier: Modifier) {
         if (additional.isNotEmpty()) {
             Text(
                 additional,
-                style = MaterialTheme.typography.bodySmall,
+                style = ChromeType.label,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
                 modifier = Modifier.padding(horizontal = 16.dp),
             )
@@ -314,12 +398,12 @@ private fun InputSignIn(method: InputSignInMethod, modifier: Modifier) {
     val masked = method.inputType == InputSignInMethod.INPUT_TYPE_PASSWORD
 
     Column(modifier) {
-        SearchField(if (masked) "•".repeat(value.length) else value, method.hint.text())
+        SearchField(if (masked) "•".repeat(value.length) else value, method.hint.text(), searchIcon = false)
         val error = method.errorMessage.text()
         if (error.isNotEmpty()) {
             Text(
                 error,
-                style = MaterialTheme.typography.bodySmall,
+                style = ChromeType.label,
                 color = MaterialTheme.colorScheme.error,
                 modifier = Modifier.padding(horizontal = 16.dp),
             )
@@ -343,8 +427,7 @@ private fun Callout(value: String, modifier: Modifier) {
     Box(modifier.fillMaxWidth(), contentAlignment = Alignment.Center) {
         Text(
             value,
-            style = MaterialTheme.typography.headlineMedium,
-            fontWeight = FontWeight.Bold,
+            style = ChromeType.headline,
             textAlign = androidx.compose.ui.text.style.TextAlign.Center,
         )
     }
@@ -355,43 +438,62 @@ private fun Callout(value: String, modifier: Modifier) {
 @Composable
 private fun TabContent(template: TabTemplate, modifier: Modifier) {
     val active = template.activeTabContentId
-    ContentSurface(modifier) {
-        Row(
-            Modifier
-                .fillMaxWidth()
-                .padding(horizontal = 8.dp, vertical = 6.dp)
-                .verticalScrollNone(),
-            horizontalArrangement = Arrangement.spacedBy(6.dp),
-            verticalAlignment = Alignment.CenterVertically,
-        ) {
-            template.headerAction?.let { ActionButton(it) }
-            template.tabs.forEach { tab ->
-                val selected = tab.contentId == active
-                Surface(
-                    color = if (selected) MaterialTheme.colorScheme.primaryContainer
-                    else MaterialTheme.colorScheme.surfaceContainerHighest,
-                    contentColor = if (selected) MaterialTheme.colorScheme.onPrimaryContainer
-                    else MaterialTheme.colorScheme.onSurface,
-                    shape = RoundedCornerShape(20.dp),
-                    modifier = Modifier.clickable {
-                        template.tabCallbackDelegate.tabSelected(tab.contentId)
-                    },
-                ) {
-                    Row(
-                        Modifier.padding(horizontal = 12.dp, vertical = 8.dp),
-                        verticalAlignment = Alignment.CenterVertically,
+    val innerTemplate = template.tabContents?.template
+    // A sectioned tab's own actions (search, a Liked Songs shortcut) belong on the same line as
+    // the tabs themselves - a real Android Auto host's header row, not a second near-empty row
+    // underneath it that SectionedContent would otherwise draw just to hold them.
+    val trailingActions = (innerTemplate as? SectionedItemTemplate)?.actions.orEmpty().filter { it.isDrawable() }
+    Box(modifier) {
+        ContentSurface(Modifier.fillMaxSize()) {
+            Row(
+                Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 8.dp, vertical = 6.dp)
+                    .verticalScrollNone(),
+                horizontalArrangement = Arrangement.spacedBy(6.dp),
+                verticalAlignment = Alignment.CenterVertically,
+            ) {
+                template.headerAction?.let { ActionButton(it) }
+                template.tabs.forEach { tab ->
+                    val selected = tab.contentId == active
+                    GsIconBox(
+                        onClick = { template.tabCallbackDelegate.tabSelected(tab.contentId) },
+                        colors = if (selected) GsColors(MaterialTheme.colorScheme.primaryContainer, MaterialTheme.colorScheme.onPrimaryContainer)
+                        else GsColors(MaterialTheme.colorScheme.surfaceContainerHighest, MaterialTheme.colorScheme.onSurface),
+                        shape = RoundedCornerShape(20.dp),
+                        latched = selected,
                     ) {
-                        tab.icon?.let {
-                            CarGlyph(it, Modifier.size(20.dp))
-                            Spacer(Modifier.width(6.dp))
+                        Row(
+                            Modifier.padding(horizontal = 12.dp, vertical = 8.dp),
+                            verticalAlignment = Alignment.CenterVertically,
+                        ) {
+                            tab.icon?.let {
+                                CarGlyph(it, Modifier.size(20.dp))
+                                Spacer(Modifier.width(6.dp))
+                            }
+                            Text(tab.title.text(), style = ChromeType.label, maxLines = 1)
                         }
-                        Text(tab.title.text(), style = MaterialTheme.typography.labelLarge, maxLines = 1)
                     }
                 }
             }
+            if (template.isLoading) Loading()
+            else ContentTemplate(
+                innerTemplate,
+                Modifier.weight(1f),
+                ownActionsElsewhere = trailingActions.isNotEmpty(),
+                tabId = active.orEmpty(),
+            )
+        }
+        // Bottom-left, not on the tab row: a driver's hand rests near the bottom of the screen,
+        // and the tab row is already busy with the tabs themselves.
+        if (trailingActions.isNotEmpty()) {
+            Row(
+                Modifier.align(Alignment.BottomStart).padding(12.dp),
+                horizontalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                trailingActions.forEach { ActionButton(it) }
+            }
         }
-        if (template.isLoading) Loading()
-        else ContentTemplate(template.tabContents?.template, Modifier.weight(1f))
     }
 }
 
@@ -400,46 +502,66 @@ private fun Modifier.verticalScrollNone(): Modifier = this
 
 // --- sectioned items --------------------------------------------------------------------------
 
+/**
+ * A section's items ([SectionRows]) are cached for the life of the process, keyed off the
+ * foreground app and, when nested under a tab, the tab - so flipping back to a shelf already
+ * seen this drive is instant instead of re-asking the app over the binder. Bounded and in
+ * memory only, so it costs nothing on disk and disappears with the process.
+ */
+private val sectionCache = android.util.LruCache<String, List<Item>>(64)
+
 /**
  * Sections fetch their items across the binder on demand rather than carrying them, so each one
- * is asked for its full range once and the answer is held while the section is on screen.
+ * is asked for its full range once and the answer is held while the section is on screen (and,
+ * via [sectionCache], for the rest of the drive).
  */
 @Composable
-private fun SectionedContent(template: SectionedItemTemplate, modifier: Modifier) {
+private fun SectionedContent(template: SectionedItemTemplate, modifier: Modifier, showActionsInHeader: Boolean = true, tabId: String = "") {
+    val appPackage = CarServices.nav.appPackage.orEmpty()
     ContentSurface(modifier) {
+        // The app's own actions (Spotify's search and Liked Songs shortcut, for two) come from
+        // template.actions, not the header - but a bottom-of-content row is wrong for a driver
+        // reaching for it. Normally the header's own end-actions slot is where a real Android
+        // Auto host puts these; nested under a TabTemplate, though, TabContent already drew them
+        // on the tab row itself, so showActionsInHeader is false and this header stays title-only
+        // (and usually collapses to nothing, since a tab's own content carries no separate title).
         HeaderBar(
             headerTitle(template.header, ""),
             template.header?.startHeaderAction,
-            template.header?.endHeaderActions.orEmpty(),
+            template.header?.endHeaderActions.orEmpty() + if (showActionsInHeader) template.actions.orEmpty() else emptyList(),
         )
         if (template.isLoading) {
             Loading()
             return@ContentSurface
         }
         Column(Modifier.weight(1f).verticalScroll(rememberScrollState())) {
-            template.sections.forEach { section ->
+            template.sections.forEachIndexed { index, section ->
                 PaneTitle(section.title.text())
-                SectionRows(section)
+                SectionRows(section, "$appPackage/$tabId/$index/${section.title.text()}")
             }
         }
-        ActionRow(template.actions.orEmpty(), Modifier.padding(12.dp))
     }
 }
 
 @Composable
-private fun SectionRows(section: Section<*>) {
-    var items by remember(section) { mutableStateOf<List<Item>>(emptyList()) }
+private fun SectionRows(section: Section<*>, cacheKey: String) {
+    var items by remember(section) { mutableStateOf(sectionCache.get(cacheKey).orEmpty()) }
 
     LaunchedEffect(section) {
+        if (sectionCache.get(cacheKey) != null) return@LaunchedEffect
         val delegate = section.itemsDelegate
-        val size = runCatching { delegate.size }.getOrDefault(0)
+        val sizeResult = runCatching { delegate.size }
+        val size = sizeResult.getOrDefault(0)
+        sizeResult.onFailure { GearslipLog.w("host: section.itemsDelegate.size threw: ${it.javaClass.simpleName}: ${it.message}") }
         if (size <= 0) return@LaunchedEffect
         runCatching {
             delegate.requestItemRange(0, size - 1, object : OnDoneCallback {
                 override fun onSuccess(response: Bundleable?) {
                     val value = response?.let { runCatching { it.get() }.getOrNull() }
                     @Suppress("UNCHECKED_CAST")
-                    items = (value as? List<Item>).orEmpty()
+                    val fetched = (value as? List<Item>).orEmpty()
+                    items = fetched
+                    sectionCache.put(cacheKey, fetched)
                 }
 
                 override fun onFailure(response: Bundleable) =
@@ -450,34 +572,62 @@ private fun SectionRows(section: Section<*>) {
 
     if (items.isEmpty()) {
         val message = section.noItemsMessage.text()
-        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp))
+        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp), style = ChromeType.body)
         return
     }
-    items.filterIsInstance<CarRow>().forEach { RowItem(it) }
+    // A section's items are homogeneous in practice - one kind or the other - but nothing in
+    // the API guarantees that, so both are handled rather than assuming whichever the app
+    // happened to send first.
+    val rows = items.filterIsInstance<CarRow>()
+    val tiles = items.filterIsInstance<GridItem>()
+    rows.forEach { RowItem(it) }
+    if (tiles.isNotEmpty()) {
+        // A plain scrollable Row, not LazyRow: the car screen renders into a VirtualDisplay
+        // Presentation rather than a normal window, and LazyRow's SubcomposeLayout measures to
+        // zero height there even with an explicit size - a handful of tiles per shelf makes the
+        // lost virtualization no real loss.
+        Row(
+            Modifier
+                .fillMaxWidth()
+                .horizontalScroll(rememberScrollState())
+                .padding(horizontal = 8.dp, vertical = 4.dp),
+            horizontalArrangement = Arrangement.spacedBy(4.dp),
+        ) {
+            tiles.forEach { tile -> GridTile(tile, Modifier.width(180.dp)) }
+        }
+    }
 }
 
 // --- media ----------------------------------------------------------------------------------
 
 /**
- * Media playback is drawn from the app's MediaSession rather than from the template, which
- * carries only a header. Gearslip has no media channel yet, so this says so plainly instead of
- * showing an empty player.
+ * The template itself carries only a header - real Android Auto hosts draw this screen from the
+ * app's MediaSession instead, which is exactly what [CarServices.media] already does for the
+ * media-app launcher and the bottom bar. Reusing [NowPlayingPage] here rather than a "not
+ * supported" placeholder means an app whose own now-playing template Gearslip lands on (like
+ * Spotify's "Liked Songs" screen) still gets working transport controls.
  */
 @Composable
 private fun MediaPlaybackContent(template: MediaPlaybackTemplate, modifier: Modifier) {
+    val media = CarServices.media
+    val now by media.now.collectAsState()
     ContentSurface(modifier) {
         HeaderBar(
             headerTitle(template.header, ""),
             template.header?.startHeaderAction,
             template.header?.endHeaderActions.orEmpty(),
         )
-        Box(Modifier.weight(1f).fillMaxWidth(), contentAlignment = Alignment.Center) {
-            Text(
-                "Playback controls come from the app's media session,\nwhich Gearslip doesn't carry yet.",
-                style = MaterialTheme.typography.bodyMedium,
-                color = MaterialTheme.colorScheme.onSurfaceVariant,
-                textAlign = androidx.compose.ui.text.style.TextAlign.Center,
-            )
+        if (now.title.isNotEmpty()) {
+            NowPlayingPage(now, media, Modifier.weight(1f).fillMaxWidth())
+        } else {
+            Box(Modifier.weight(1f).fillMaxWidth(), contentAlignment = Alignment.Center) {
+                Text(
+                    "Nothing playing yet.",
+                    style = ChromeType.body,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    textAlign = androidx.compose.ui.text.style.TextAlign.Center,
+                )
+            }
         }
     }
 }
@@ -496,6 +646,6 @@ private typealias ColumnScopeAlias = androidx.compose.foundation.layout.ColumnSc
 @Composable
 private fun Loading() {
     Box(Modifier.fillMaxWidth().height(80.dp), contentAlignment = Alignment.Center) {
-        Text("Loading…", style = MaterialTheme.typography.bodyLarge)
+        Text("Loading…", style = ChromeType.title)
     }
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/TemplateParts.kt

@@ -1,15 +1,24 @@
 package app.seb3thehacker.gearslip.car
 
+import app.seb3thehacker.gearslip.car.theme.*
+import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
+import androidx.compose.ui.focus.onFocusChanged
 import androidx.compose.material3.LocalContentColor
 import androidx.compose.ui.graphics.ColorFilter
+import androidx.compose.ui.graphics.luminance
+import androidx.compose.ui.graphics.ImageBitmap
 import androidx.compose.foundation.Image
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
@@ -22,6 +31,7 @@ import androidx.compose.foundation.lazy.grid.items
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Call
 import androidx.compose.material.icons.filled.ArrowBack
 import androidx.compose.material.icons.filled.Menu
 import androidx.compose.material.icons.filled.Warning
@@ -82,19 +92,21 @@ import app.seb3thehacker.gearslip.host.text
 /**
  * The app keeps drawing its map across the whole surface - the visible area we report tells it
  * where to put its own markers, not where to stop painting. So anything the host lays over the
- * map is opaque by default, or the map reads through it.
+ * map is opaque, always, in the same one colour: a card that lets the map show through in places
+ * reads as broken glass, not as a deliberate choice, and a driver has no way to tell which was
+ * meant. There is no alpha knob here on purpose - every card, bar and strip in the template
+ * chrome shares this surface, so nothing drawn over a map is ever see-through.
  */
 @Composable
 internal fun ChromeSurface(
     modifier: Modifier = Modifier,
     shape: Shape = RoundedCornerShape(16.dp),
-    alpha: Float = 1f,
     shadowElevation: androidx.compose.ui.unit.Dp = 0.dp,
     content: @Composable () -> Unit,
 ) {
     Surface(
         shadowElevation = shadowElevation,
-        color = MaterialTheme.colorScheme.surface.copy(alpha = alpha),
+        color = MaterialTheme.colorScheme.surface,
         contentColor = MaterialTheme.colorScheme.onSurface,
         shape = shape,
         modifier = modifier,
@@ -102,6 +114,32 @@ internal fun ChromeSurface(
     )
 }
 
+/**
+ * The one type scale for everything a templated app's screen draws. Apps hand the host plain
+ * strings with no size of their own - the Car App Library deliberately keeps that decision out of
+ * their hands - so without a shared scale, each template's text ends up whatever size felt right
+ * when that template was written, and two apps' otherwise-identical rows read as different sizes
+ * of importance. Every car chrome file should reach for one of these four rather than naming a
+ * Material size directly.
+ */
+internal object ChromeType {
+    /** The one number or word a card exists to show: distance to a turn, minutes left, a PIN. */
+    val headline: androidx.compose.ui.text.TextStyle
+        @Composable get() = MaterialTheme.typography.headlineMedium.copy(fontWeight = FontWeight.Bold)
+
+    /** A row's name, a header, a manoeuvre's instruction - the line the rest is supporting. */
+    val title: androidx.compose.ui.text.TextStyle
+        @Composable get() = MaterialTheme.typography.titleLarge.copy(fontWeight = FontWeight.SemiBold)
+
+    /** Supporting detail: a road, an address, a message's body, a second line under a title. */
+    val body: androidx.compose.ui.text.TextStyle
+        @Composable get() = MaterialTheme.typography.titleMedium
+
+    /** The smallest text Gearslip draws over a map - still large enough to read while moving. */
+    val label: androidx.compose.ui.text.TextStyle
+        @Composable get() = MaterialTheme.typography.bodyLarge
+}
+
 @Composable
 internal fun UnsupportedChrome(template: Template, modifier: Modifier = Modifier) {
     androidx.compose.foundation.layout.Box(modifier, contentAlignment = Alignment.Center) {
@@ -109,7 +147,7 @@ internal fun UnsupportedChrome(template: Template, modifier: Modifier = Modifier
             Text(
                 "${template.javaClass.simpleName} isn't drawn yet",
                 Modifier.padding(16.dp),
-                style = MaterialTheme.typography.titleMedium,
+                style = ChromeType.title,
             )
         }
     }
@@ -142,8 +180,7 @@ internal fun HeaderBar(
         startAction?.takeIf { it.isDrawable() }?.let { ActionButton(it) }
         Text(
             title,
-            style = MaterialTheme.typography.titleLarge,
-            fontWeight = FontWeight.SemiBold,
+            style = ChromeType.title,
             color = MaterialTheme.colorScheme.onSurface,
             maxLines = 1,
             overflow = TextOverflow.Ellipsis,
@@ -197,7 +234,9 @@ internal fun RightEdgeControls(
     // the first touch on one wakes them rather than pressing it.
     val awake = LocalMapControlsWake.current.awake
     val pan by CarServices.nav.panMode.collectAsState()
-    val visible = awake || pan
+    // Kept up while the knob is on one of them, or the ring would fade out along with the button.
+    var holdsFocus by remember { mutableStateOf(false) }
+    val visible = awake || pan || holdsFocus
     val alpha by androidx.compose.animation.core.animateFloatAsState(
         targetValue = if (visible) 1f else 0f,
         animationSpec = androidx.compose.animation.core.tween(if (visible) 150 else 500),
@@ -206,6 +245,7 @@ internal fun RightEdgeControls(
     Column(
         modifier
             .alpha(alpha)
+            .onFocusChanged { holdsFocus = it.hasFocus }
             .let { base ->
                 if (visible) base else base.pointerInput(Unit) {
                     awaitPointerEventScope {
@@ -267,15 +307,17 @@ internal fun ActionButton(action: Action, large: Boolean = false, modifier: Modi
     }
     val hasGlyph = action.icon != null || action.type != Action.TYPE_CUSTOM
 
-    Surface(
-        color = background,
-        contentColor = content,
-        shape = if (title.isEmpty()) androidx.compose.foundation.shape.CircleShape else RoundedCornerShape(if (large) 28.dp else 24.dp),
-        modifier = modifier.clickable(enabled = action.isEnabled) {
+    GsIconBox(
+        onClick = {
             if (action.type == Action.TYPE_BACK) CarServices.nav.backPressed()
             else if (action.type == Action.TYPE_PAN) CarServices.nav.setPanMode(!panOn)
             else action.onClickDelegate?.click("action")
         },
+        modifier = modifier,
+        colors = GsColors(background, content),
+        enabled = action.isEnabled,
+        shape = if (title.isEmpty()) androidx.compose.foundation.shape.CircleShape else RoundedCornerShape(if (large) 28.dp else 24.dp),
+        latched = active,
     ) {
         if (large && title.isNotEmpty()) {
             // The label sits dead centre on the button; the icon hangs off the left edge, so the
@@ -285,12 +327,7 @@ internal fun ActionButton(action: Action, large: Boolean = false, modifier: Modi
                 contentAlignment = Alignment.Center,
             ) {
                 if (hasGlyph) CarGlyph(action.icon, Modifier.size(30.dp).align(Alignment.CenterStart), standardFor(action))
-                Text(
-                    title,
-                    style = MaterialTheme.typography.titleLarge,
-                    fontWeight = FontWeight.SemiBold,
-                    maxLines = 1,
-                )
+                Text(title, style = ChromeType.title, maxLines = 1)
             }
         } else if (title.isEmpty()) {
             // Every icon-only button - back, settings, the map's zoom and locate - is the same size.
@@ -304,12 +341,83 @@ internal fun ActionButton(action: Action, large: Boolean = false, modifier: Modi
             ) {
                 if (hasGlyph) CarGlyph(action.icon, Modifier.size(24.dp), standardFor(action))
                 if (hasGlyph) Spacer(Modifier.width(8.dp))
-                Text(title, style = MaterialTheme.typography.titleMedium, maxLines = 1)
+                Text(title, style = ChromeType.body, maxLines = 1)
             }
         }
     }
 }
 
+/**
+ * A large action that fires on its own after five seconds, filling to show the countdown - for
+ * the one button on a map-preview pane, where the app is proposing a single place or route and a
+ * driver glancing at the car screen has already decided. Tapping it, same as any other button,
+ * fires it at once; the fill is only ever a preview of what a touch already does.
+ */
+@Composable
+internal fun AutoStartButton(action: Action, modifier: Modifier = Modifier) {
+    var fraction by remember(action.identity()) { mutableStateOf(0f) }
+    var fired by remember(action.identity()) { mutableStateOf(false) }
+    fun fire() {
+        if (fired) return
+        fired = true
+        action.onClickDelegate.click("auto-start")
+    }
+    androidx.compose.runtime.LaunchedEffect(action.identity()) {
+        val steps = 60
+        repeat(steps) { step ->
+            kotlinx.coroutines.delay(AUTO_START_MS / steps)
+            fraction = (step + 1) / steps.toFloat()
+        }
+        fire()
+    }
+
+    val dark = MaterialTheme.colorScheme.surface.luminanceIsDark()
+    val custom = action.backgroundColor?.type?.let { it != androidx.car.app.model.CarColor.TYPE_DEFAULT } == true
+    val background = action.backgroundColor.color(dark, MaterialTheme.colorScheme.primary)
+    val content = if (custom) Color.White else MaterialTheme.colorScheme.onPrimary
+    val hasGlyph = action.icon != null
+
+    GsIconBox(
+        onClick = { fire() },
+        modifier = modifier.fillMaxWidth(),
+        // An unfilled track, solid, not the button's own colour dimmed with alpha - so the map
+        // behind never shows through however much of the five seconds is left.
+        colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHighest, content),
+        enabled = action.isEnabled,
+        shape = RoundedCornerShape(28.dp),
+    ) {
+        androidx.compose.foundation.layout.Box {
+            // The countdown itself: a plain fill sweeping left to right underneath the label.
+            // matchParentSize(), not fillMaxHeight() - this Box sits beside a label Box that
+            // wraps its own content, and the outer Box sizes itself to its tallest child; a
+            // plain fillMaxHeight() here has nothing bounded to fill up to but the whole screen,
+            // which is what was stretching the whole button that tall. matchParentSize() instead
+            // takes whatever size the label ends up being, without itself voting on what that is.
+            androidx.compose.foundation.layout.Box(Modifier.matchParentSize()) {
+                androidx.compose.foundation.layout.Box(
+                    Modifier
+                        .fillMaxWidth(fraction)
+                        .fillMaxHeight()
+                        .background(background),
+                )
+            }
+            androidx.compose.foundation.layout.Box(
+                Modifier.fillMaxWidth().padding(horizontal = 20.dp, vertical = 16.dp),
+                contentAlignment = Alignment.Center,
+            ) {
+                if (hasGlyph) CarGlyph(action.icon, Modifier.size(24.dp).align(Alignment.CenterStart))
+                Text(
+                    action.title.text().ifEmpty { "Start" },
+                    style = ChromeType.title,
+                    maxLines = 1,
+                )
+            }
+        }
+    }
+}
+
+private const val AUTO_START_MS = 5_000L
+
 /** The connected app's own launcher icon, which is what the app-icon action stands for. */
 @Composable
 private fun AppIconBadge() {
@@ -330,9 +438,16 @@ private fun standardFor(action: Action): Int? = when (action.type) {
     Action.TYPE_BACK -> CarIcon.TYPE_BACK
     Action.TYPE_PAN -> CarIcon.TYPE_PAN
     Action.TYPE_APP_ICON -> CarIcon.TYPE_APP_ICON
+    ACTION_TYPE_NOW_PLAYING -> ACTION_TYPE_NOW_PLAYING
     else -> null
 }
 
+/**
+ * The media "now playing" standard action, newer than the Car App Library we build against, so it
+ * has no named constant here. Spotify puts it in its header with no icon of its own.
+ */
+private const val ACTION_TYPE_NOW_PLAYING = 65542
+
 // --- icons ----------------------------------------------------------------------------------
 
 /**
@@ -343,7 +458,14 @@ private fun standardFor(action: Action): Int? = when (action.type) {
 @Composable
 internal fun CarGlyph(icon: CarIcon?, modifier: Modifier = Modifier, standard: Int? = null) {
     val context = LocalContext.current
-    val bitmap = icon.image(context)
+    // Off the main thread and cached per icon: loadDrawable() is a Binder round trip into the
+    // app's own process for a content:// icon, plus a bitmap decode - done synchronously on the
+    // composition thread for every tile on screen, that's what made a shelf of ten covers feel
+    // like it was hanging rather than loading.
+    val bitmapState by produceState<ImageBitmap?>(null, icon) {
+        value = withContext(Dispatchers.IO) { icon.image(context) }
+    }
+    val bitmap = bitmapState
     if (bitmap != null) {
         // An icon that names a tint (DEFAULT included) expects the host to colour it for the
         // surface it sits on; without this a white glyph vanishes on a light theme.
@@ -352,7 +474,10 @@ internal fun CarGlyph(icon: CarIcon?, modifier: Modifier = Modifier, standard: I
         val white = remember(bitmap) { bitmap.isPlainWhite() }
         // Untinted white artwork is a template-app habit from dark surfaces; it is coloured like
         // text so it stays readable on a light one.
-        val tint = icon?.tint?.color(dark, content) ?: content.takeIf { white }
+        // An app's own tint is kept only if it can be seen: MAPS.ME asks for dark grey on dark
+        // buttons. Android Auto drops colours that fail contrast the same way.
+        val tint = icon?.tint?.color(dark, content)?.takeIf { it.readableOn(content) }
+            ?: content.takeIf { white || icon?.tint != null }
         Image(
             bitmap, contentDescription = null, modifier = modifier,
             colorFilter = tint?.let { ColorFilter.tint(it) },
@@ -364,6 +489,7 @@ internal fun CarGlyph(icon: CarIcon?, modifier: Modifier = Modifier, standard: I
         CarIcon.TYPE_ALERT, CarIcon.TYPE_ERROR -> Icons.Filled.Warning
         // No four-way pan glyph in material-icons-core; this is the closest honest stand-in.
         CarIcon.TYPE_PAN -> Icons.Filled.Menu
+        ACTION_TYPE_NOW_PLAYING -> MediaIcons.Equalizer
         else -> null
     } ?: return
     Icon(vector, contentDescription = null, modifier = modifier)
@@ -376,8 +502,7 @@ internal fun PaneTitle(title: String) {
     if (title.isEmpty()) return
     Text(
         title,
-        style = MaterialTheme.typography.titleMedium,
-        fontWeight = FontWeight.SemiBold,
+        style = ChromeType.title,
         modifier = Modifier.padding(horizontal = 14.dp, vertical = 10.dp),
     )
 }
@@ -394,7 +519,7 @@ internal fun ItemListColumn(
     }
     if (rows.isEmpty()) {
         val message = single?.noItemsMessage.text()
-        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp))
+        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp), style = ChromeType.body)
         return
     }
     // A list the app made selectable is a single-choice list: one option chosen, shown as a radio.
@@ -407,7 +532,9 @@ internal fun ItemListColumn(
     }
 }
 
-/** A grid of large tappable tiles - what apps use for a home screen beside the map. */
+/** A grid of tappable tiles - what apps use for a home screen beside the map. Icons here are as
+ * often a small menu glyph (Organic Maps' Search, say) as real cover art, so the tile stays
+ * modest; [GridTile]'s own default is for the shelf case, where every tile is a photo. */
 @Composable
 internal fun GridItems(list: ItemList?, modifier: Modifier = Modifier) {
     val items = list?.items?.filterIsInstance<GridItem>().orEmpty()
@@ -419,50 +546,191 @@ internal fun GridItems(list: ItemList?, modifier: Modifier = Modifier) {
         horizontalArrangement = Arrangement.spacedBy(6.dp),
         verticalArrangement = Arrangement.spacedBy(6.dp),
     ) {
-        items(items) { item ->
-            Column(
-                Modifier
-                    .clickable { item.onClickDelegate.click("grid item") }
-                    .padding(vertical = 8.dp),
-                horizontalAlignment = Alignment.CenterHorizontally,
+        items(items) { item -> GridTile(item, iconSize = 36.dp) }
+    }
+}
+
+/**
+ * One cover-art tile: an app's own icon over a title and optional subtitle. Shared by
+ * [GridItems] (a whole screen of tiles, [iconSize] scaled down there to suit a plain menu glyph)
+ * and a section's horizontal shelf, which carries the same [GridItem] type but scrolls sideways
+ * instead of wrapping into a grid and wants its full-size cover art.
+ */
+@Composable
+internal fun GridTile(item: GridItem, modifier: Modifier = Modifier, iconSize: androidx.compose.ui.unit.Dp = 144.dp) {
+    Column(
+        modifier
+            .clickable { item.onClickDelegate.click("grid item") }
+            .padding(vertical = 8.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        CarGlyph(item.image, Modifier.size(iconSize))
+        Spacer(Modifier.height(6.dp))
+        Text(
+            item.title.text(),
+            style = ChromeType.label,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+        )
+        val subtitle = item.text.text()
+        if (subtitle.isNotEmpty()) {
+            Text(
+                subtitle,
+                style = ChromeType.label,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+            )
+        }
+    }
+}
+
+/**
+ * [autoStart] is for a pane floating over a map - a place or a route the app is proposing - where
+ * a single action counts itself down rather than waiting to be pressed, on the theory that a
+ * driver glancing at the car screen has already decided. It never applies to more than one
+ * action: a pane offering a real choice (Start vs. something else) always waits to be tapped.
+ */
+@Composable
+internal fun PaneRows(pane: Pane?, modifier: Modifier = Modifier, autoStart: Boolean = false) {
+    // Some apps pad a pane with a row of blank strings; drawn, it is just a gap.
+    val rows = pane?.rows.orEmpty().filterNot { it.isBlank() }
+    val actions = pane?.actions.orEmpty().filter { it.isDrawable() }
+    val card = PlaceCard.of(rows)
+    Column(modifier) {
+        card.heading?.let { PlaceHeading(it) }
+        if (card.buttons.isNotEmpty()) RowButtons(card.buttons, Modifier.padding(horizontal = 14.dp, vertical = 6.dp))
+        if (autoStart && actions.size == 1) {
+            AutoStartButton(actions.single(), Modifier.padding(horizontal = 14.dp, vertical = 10.dp))
+        } else {
+            ActionRow(actions, Modifier.padding(horizontal = 14.dp, vertical = 10.dp), large = true)
+        }
+        if (card.heading == null && card.buttons.isEmpty()) {
+            card.details.forEach { RowItem(it, large = true) }
+        } else {
+            card.details.forEach { DetailRow(it, card.heading?.title?.text().orEmpty()) }
+        }
+    }
+}
+
+/**
+ * A pane split the way a place page reads: a name on top, the things to do with it as buttons,
+ * then the facts. Apps send all three as plain rows, so the split is worked out from the rows'
+ * shape alone. A pane that doesn't fit the shape - all of it tappable, like a menu - gets no
+ * heading and no buttons, and draws exactly as a plain list of rows.
+ */
+private class PlaceCard(val heading: CarRow?, val buttons: List<CarRow>, val details: List<CarRow>) {
+    companion object {
+        fun of(rows: List<CarRow>): PlaceCard {
+            // A short tappable row with an icon and nothing under it is a button in all but name:
+            // MAPS.ME's "Let's go" and "Save".
+            val buttons = rows.filter {
+                it.onClickDelegate != null && it.toggle == null && it.image != null &&
+                    it.texts.orEmpty().isEmpty() && it.title.text().length <= 24
+            }.takeIf { it.size in 1..4 && it.size < rows.size }.orEmpty()
+            // A first row that can't be tapped and has no icon is the place's name and kind.
+            val heading = rows.firstOrNull()?.takeIf {
+                buttons.isNotEmpty() && it.onClickDelegate == null && it.image == null && it.toggle == null
+            }
+            return PlaceCard(heading, buttons, rows - buttons.toSet() - listOfNotNull(heading).toSet())
+        }
+    }
+}
+
+@Composable
+private fun PlaceHeading(row: CarRow) {
+    Column(Modifier.fillMaxWidth().padding(horizontal = 14.dp, vertical = 6.dp)) {
+        Text(row.title.text(), style = ChromeType.title, maxLines = 2, overflow = TextOverflow.Ellipsis)
+        row.texts.orEmpty().take(2).forEach {
+            Text(it.text(), style = ChromeType.body, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
+        }
+    }
+}
+
+/** Button-shaped rows side by side, the first one filled as the thing most drivers came to do. */
+@Composable
+private fun RowButtons(rows: List<CarRow>, modifier: Modifier) {
+    val scheme = MaterialTheme.colorScheme
+    Row(modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+        rows.forEachIndexed { i, row ->
+            GsIconBox(
+                onClick = { row.onClickDelegate.click("row") },
+                modifier = Modifier.weight(1f),
+                colors = if (i == 0) GsColors(scheme.primary, scheme.onPrimary) else GsColors(scheme.surfaceContainerHighest, scheme.onSurface),
+                enabled = row.isEnabled,
+                shape = RoundedCornerShape(24.dp),
             ) {
-                CarGlyph(item.image, Modifier.size(36.dp))
-                Spacer(Modifier.height(6.dp))
-                Text(
-                    item.title.text(),
-                    style = MaterialTheme.typography.labelLarge,
-                    maxLines = 1,
-                    overflow = TextOverflow.Ellipsis,
-                )
-                val subtitle = item.text.text()
-                if (subtitle.isNotEmpty()) {
-                    Text(
-                        subtitle,
-                        style = MaterialTheme.typography.labelSmall,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant,
-                        maxLines = 1,
-                        overflow = TextOverflow.Ellipsis,
-                    )
+                Row(
+                    Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 14.dp),
+                    horizontalArrangement = Arrangement.Center,
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    CarGlyph(row.image, Modifier.size(24.dp))
+                    Spacer(Modifier.width(8.dp))
+                    Text(row.title.text(), style = ChromeType.body, maxLines = 1, overflow = TextOverflow.Ellipsis)
                 }
             }
         }
     }
 }
 
+/**
+ * One fact about a place, tighter than a list row: a small label over its value, or just the
+ * value when the row has no label. A phone number gets a Call button that asks first.
+ */
 @Composable
-internal fun PaneRows(pane: Pane?, modifier: Modifier = Modifier) {
-    // Some apps pad a pane with a row of blank strings; drawn, it is just a gap.
-    val rows = pane?.rows.orEmpty().filterNot { it.isBlank() }
-    Column(modifier) {
-        rows.forEach { RowItem(it, large = true) }
-        ActionRow(
-            pane?.actions.orEmpty(),
-            Modifier.padding(horizontal = 14.dp, vertical = 10.dp),
-            large = true,
-        )
+private fun DetailRow(row: CarRow, placeName: String) {
+    val context = LocalContext.current
+    val texts = row.texts.orEmpty().map { it.text() }.filter { it.isNotBlank() }
+    val label = row.title.text().takeIf { texts.isNotEmpty() }
+    val values = texts.ifEmpty { listOf(row.title.text()) }
+    val number = values.firstOrNull { it.isPhoneNumber() }
+    val canCall = number != null &&
+        context.checkSelfPermission(android.Manifest.permission.CALL_PHONE) == android.content.pm.PackageManager.PERMISSION_GRANTED
+    Row(
+        Modifier
+            .fillMaxWidth()
+            .let { if (row.onClickDelegate != null && row.isEnabled) it.clickable { row.onClickDelegate.click("row") } else it }
+            .padding(horizontal = 14.dp, vertical = 6.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        row.image?.let {
+            CarGlyph(it, Modifier.size(24.dp))
+            Spacer(Modifier.width(12.dp))
+        }
+        Column(Modifier.weight(1f)) {
+            label?.let {
+                Text(it, style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1)
+            }
+            values.take(3).forEach {
+                Text(it, style = ChromeType.body, maxLines = 2, overflow = TextOverflow.Ellipsis)
+            }
+        }
+        if (canCall) {
+            Spacer(Modifier.width(8.dp))
+            GsIconBox(
+                onClick = { CallPrompt.ask(placeName.ifBlank { number!! }, number!!) },
+                colors = GsColors(MaterialTheme.colorScheme.primary, MaterialTheme.colorScheme.onPrimary),
+                shape = RoundedCornerShape(24.dp),
+            ) {
+                Row(Modifier.padding(horizontal = 16.dp, vertical = 10.dp), verticalAlignment = Alignment.CenterVertically) {
+                    androidx.compose.material3.Icon(Icons.Filled.Call, null, Modifier.size(20.dp))
+                    Spacer(Modifier.width(6.dp))
+                    Text("Call", style = ChromeType.body)
+                }
+            }
+        }
+        ActionRow(row.actions.orEmpty())
     }
 }
 
+/** A line that is only a phone number: digits with the usual separators, 7 to 15 digits long. */
+private fun String.isPhoneNumber(): Boolean {
+    val t = trim()
+    if (!Regex("""^\+?[0-9 ().\-]+$""").matches(t)) return false
+    return t.count { it.isDigit() } in 7..15
+}
+
 @Composable
 internal fun RowItem(row: CarRow, selection: RowSelection? = null, large: Boolean = false) {
     val toggle = row.toggle
@@ -496,18 +764,20 @@ internal fun RowItem(row: CarRow, selection: RowSelection? = null, large: Boolea
             CarGlyph(it, Modifier.size(28.dp))
             Spacer(Modifier.width(12.dp))
         }
+        // large only changes how much room a row gets (more lines, a bigger icon above) - the
+        // type itself is the same scale as every other row, so a pane's one row and a plain
+        // list's tenth row read as the same kind of text.
         Column(Modifier.weight(1f)) {
             Text(
                 row.title.text(),
-                style = if (large) MaterialTheme.typography.headlineSmall else MaterialTheme.typography.bodyLarge,
-                fontWeight = if (large) FontWeight.SemiBold else null,
+                style = ChromeType.title,
                 maxLines = if (large) 2 else 1,
                 overflow = TextOverflow.Ellipsis,
             )
             row.texts.orEmpty().take(if (large) 3 else 2).forEach { line ->
                 Text(
                     line.text(),
-                    style = if (large) MaterialTheme.typography.titleMedium else MaterialTheme.typography.bodyMedium,
+                    style = ChromeType.body,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                     maxLines = if (large) 2 else 1,
                     overflow = TextOverflow.Ellipsis,
@@ -525,10 +795,22 @@ internal fun RowItem(row: CarRow, selection: RowSelection? = null, large: Boolea
 /** A row's place in a single-choice list: whether it is the chosen one, and what picking it does. */
 internal class RowSelection(val selected: Boolean, val onPick: () -> Unit)
 
+/**
+ * Whether this colour stands out against the background that [content] was chosen for: at least
+ * 3:1, the WCAG minimum for icons. The background is taken as the opposite of the content colour.
+ */
+private fun Color.readableOn(content: Color): Boolean {
+    val background = if (content.luminanceIsDark()) Color.White else Color(0xFF121212)
+    val a = luminance() + 0.05f
+    val b = background.luminance() + 0.05f
+    return maxOf(a, b) / minOf(a, b) >= 3f
+}
+
 internal fun Color.luminanceIsDark(): Boolean =
     (red * 0.299f + green * 0.587f + blue * 0.114f) < 0.5f
 
 
+
 /** True for a glyph drawn entirely in white (any transparency): a mask, not a picture. */
 private fun androidx.compose.ui.graphics.ImageBitmap.isPlainWhite(): Boolean {
     val pixels = IntArray(width * height)
@@ -543,5 +825,5 @@ private fun androidx.compose.ui.graphics.ImageBitmap.isPlainWhite(): Boolean {
     return seen > 0
 }
 
-private val ICON_BUTTON_SIZE = 54.dp
+internal val ICON_BUTTON_SIZE = 54.dp
 private val ICON_BUTTON_GLYPH = 30.dp

gearslip/src/main/java/app/seb3thehacker/gearslip/car/VehicleDataScreen.kt

@@ -0,0 +1,69 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+
+/**
+ * Everything the head unit's sensor channel is willing to send, live and unfiltered - see
+ * [CarSensors] for why the labels are a best guess and the raw field dump next to each one is
+ * the part to actually trust while confirming what this unit really sends.
+ */
+@Composable
+fun VehicleDataScreen() {
+    val readings by CarSensors.readings.collectAsState()
+
+    Column(Modifier.fillMaxSize().padding(horizontal = 24.dp, vertical = 16.dp)) {
+        ScreenHeader("Vehicle data")
+        Text(
+            "Raw sensor channel from the connected head unit. Field meaning is a best guess - " +
+                "watch a row change while you do the thing (brake, drive, headlights) to confirm it.",
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.padding(top = 4.dp, bottom = 16.dp),
+        )
+
+        if (readings.isEmpty()) {
+            Text(
+                "No sensor service advertised by this head unit, or not connected.",
+                style = MaterialTheme.typography.bodyLarge,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+            return@Column
+        }
+
+        LazyColumn(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+            items(readings, key = { it.typeId }) { reading -> ReadingRow(reading) }
+        }
+    }
+}
+
+@Composable
+private fun ReadingRow(reading: CarSensors.Reading) {
+    Surface(color = MaterialTheme.colorScheme.surfaceContainerHigh, shape = MaterialTheme.shapes.large) {
+        Column(Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 12.dp)) {
+            Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                Text(reading.typeName, style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+            }
+            Text(
+                reading.raw,
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/VoiceHelpOverlay.kt

@@ -0,0 +1,94 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.car.theme.GsIconButton
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/** What the assistant understands, shown on the car screen when the driver says "help". */
+object VoiceHelp {
+    private val _shown = MutableStateFlow(false)
+    val shown: StateFlow<Boolean> = _shown.asStateFlow()
+
+    fun show() { _shown.value = true }
+    fun hide() { _shown.value = false }
+
+    /** Say this, and this happens. Kept in step with [AssistantCommands]. */
+    val COMMANDS = listOf(
+        "Navigate to…" to "Directions there. Add \"with Organic Maps\" to pick the app",
+        "Play…" to "A song, artist, or album in the open music app",
+        "Pause · Resume · Next · Previous" to "Control the music",
+        "What's playing" to "The song and artist",
+        "Call…" to "A contact by name",
+        "Open…" to "Any app, like Browser, Phone, or Screen sharing",
+        "Exit" to "Back to the car's own screen",
+        "Go home · Open apps · Settings" to "Move around Gearslip",
+        "What time is it · Weather" to "The time, or the forecast",
+        "Help" to "This list",
+    )
+}
+
+/** The command list over the car screen: read it at a glance, tap the cross or wait to dismiss. */
+@Composable
+fun VoiceHelpOverlay(modifier: Modifier = Modifier) {
+    val shown by VoiceHelp.shown.collectAsState()
+    if (!shown) return
+    // A list left up would cover the map for the rest of the drive.
+    LaunchedEffect(Unit) {
+        delay(30_000)
+        VoiceHelp.hide()
+    }
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        contentColor = MaterialTheme.colorScheme.onSurface,
+        shape = MaterialTheme.shapes.extraLarge,
+        tonalElevation = 6.dp,
+        shadowElevation = 8.dp,
+        modifier = modifier.padding(16.dp).widthIn(max = 640.dp),
+    ) {
+        Column(Modifier.padding(20.dp)) {
+            Row(Modifier.fillMaxWidth()) {
+                Text(
+                    "You can say",
+                    style = MaterialTheme.typography.titleLarge,
+                    fontWeight = FontWeight.Bold,
+                    modifier = Modifier.weight(1f).padding(top = 6.dp),
+                )
+                GsIconButton(Icons.Filled.Close, "Close", VoiceHelp::hide)
+            }
+            // Full width, so a drag anywhere on the card scrolls, not just one on the words.
+            Column(
+                Modifier.fillMaxWidth().verticalScroll(rememberScrollState()).padding(top = 8.dp),
+                verticalArrangement = Arrangement.spacedBy(10.dp),
+            ) {
+                VoiceHelp.COMMANDS.forEach { (say, does) ->
+                    Column(Modifier.fillMaxWidth()) {
+                        Text(say, style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+                        Text(does, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                    }
+                }
+            }
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/VoiceReply.kt

@@ -0,0 +1,381 @@
+package app.seb3thehacker.gearslip.car
+
+import android.content.Context
+import android.os.Handler
+import android.os.Looper
+import android.os.SystemClock
+import androidx.car.app.navigation.model.NavigationTemplate
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.call.CallUiState
+import app.seb3thehacker.gearslip.call.CarCalls
+import app.seb3thehacker.gearslip.host.clockTime
+import app.seb3thehacker.gearslip.host.remainingTime
+import app.seb3thehacker.gearslip.notify.CarNotification
+import app.seb3thehacker.gearslip.notify.CarNotifications
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * Messages by voice, the way Android Auto does it: a message is read aloud, "Do you want to
+ * reply?", a yes gets "Go ahead", the reply is read back, and it sends after a few seconds unless
+ * cancelled. Reply does the same; only once the message has just been read does it skip straight
+ * to "What's your reply?". While the reply counts down, saying "cancel" or "change it" stops it or
+ * starts it again. A quick reply sends a ready-made answer with no voice at all. Listening and speaking
+ * go through [CarAssistant], so this hears through the same microphone and recognizer.
+ *
+ * Every step runs on the main thread. Each run gets a new [run] number, and callbacks from an
+ * older run are dropped, so a cancel can never be undone by a late recognizer result.
+ */
+object VoiceReply {
+
+    enum class Phase {
+        IDLE,
+        /** Reading the message aloud. */
+        READING,
+        /** Read; the Reply button stays up for a moment in case the driver wants it. */
+        READ,
+        /** Asking "Do you want to reply?" and listening for a yes. */
+        OFFERING,
+        /** Saying "What's your reply?". */
+        ASKING,
+        LISTENING,
+        /**
+         * Reading the reply back, then counting down to [State.until] while listening for
+         * "cancel" or "change it". The countdown runs out whatever it hears.
+         */
+        CONFIRMING,
+        SENT,
+        ERROR,
+    }
+
+    data class State(
+        val phase: Phase = Phase.IDLE,
+        val target: CarNotification? = null,
+        val heard: String = "",
+        val error: String = "",
+        /**
+         * Uptime at which this step ends on its own (the card goes, or the reply sends), and how
+         * long the step was given, for the card's bar. 0 when nothing is timed.
+         */
+        val until: Long = 0L,
+        val span: Long = 0L,
+        /** While a countdown is held, how much of its bar was left, so the bar stays put. */
+        val held: Float = 0f,
+    )
+
+    const val SEND_DELAY_MS = 5_000L
+    private const val LINGER_MS = 5_000L
+    private const val SENT_MS = 2_000L
+
+    private val _state = MutableStateFlow(State())
+    val state: StateFlow<State> = _state
+
+    private val main = Handler(Looper.getMainLooper())
+    private var appContext: Context? = null
+    private var run = 0
+
+    fun init(context: Context) { appContext = context.applicationContext }
+
+    val active: Boolean get() = _state.value.phase != Phase.IDLE
+
+    /** Reads [n]'s newest messages aloud. */
+    fun read(n: CarNotification) {
+        val id = begin(State(Phase.READING, n))
+        CarAssistant.say(spoken(n)) {
+            if (id != run) return@say
+            when {
+                n.reply == null -> finish()
+                // The microphone is silent during a call, so there's no point asking.
+                CarCalls.state.value is CallUiState.Active -> idleAfterRead(id)
+                else -> offer(id)
+            }
+        }
+    }
+
+    /**
+     * "Do you want to reply?" A yes goes on to the reply; anything else ends quietly. The bar runs
+     * while it listens, so the card never looks stuck, and holds once the driver starts talking.
+     */
+    private fun offer(id: Int) {
+        _state.value = _state.value.copy(phase = Phase.OFFERING, heard = "", until = 0L, span = 0L, held = 0f)
+        CarAssistant.say("Do you want to reply?") {
+            if (id != run) return@say
+            val until = SystemClock.uptimeMillis() + OFFER_MS
+            _state.value = _state.value.copy(until = until, span = OFFER_MS)
+            // The recognizer gives up on its own; this only covers one that doesn't.
+            main.postAtTime({ if (id == run && _state.value.until != 0L) { CarAssistant.stopListening(); close() } }, until + OFFER_GRACE_MS)
+            CarAssistant.dictate(
+                onPartial = { text -> if (id == run) _state.value = _state.value.copy(heard = text) },
+                onSpeaking = {
+                    if (id != run) return@dictate
+                    val s = _state.value
+                    val left = ((s.until - SystemClock.uptimeMillis()).toFloat() / s.span).coerceIn(0.05f, 1f)
+                    _state.value = s.copy(until = 0L, span = 0L, held = left)
+                },
+                onResult = { text ->
+                    if (id != run) return@dictate
+                    if (isYes(text)) {
+                        _state.value = _state.value.copy(phase = Phase.ASKING, heard = "", until = 0L, span = 0L, held = 0f)
+                        CarAssistant.say("Go ahead.") { if (id == run) listen(id) }
+                    } else {
+                        close()
+                    }
+                },
+                // No answer counts as no: the message has been heard, so the card goes.
+                onError = { if (id == run) close() },
+            )
+        }
+    }
+
+    private fun idleAfterRead(id: Int) {
+        _state.value = _state.value.copy(phase = Phase.READ, heard = "")
+        lingerThenIdle(id)
+    }
+
+    private fun isYes(text: String): Boolean {
+        val words = words(text)
+        if (words.any { it in NO_WORDS }) return false
+        return words.any { it in YES_WORDS }
+    }
+
+    /**
+     * Reads [n] aloud and asks whether to reply, or, when the driver has just heard it, asks for
+     * the reply straight away. Then listens, reads the reply back and sends it.
+     */
+    fun reply(n: CarNotification, readFirst: Boolean = true) {
+        if (n.reply == null) {
+            val id = begin(State(Phase.ERROR, n, error = "${n.appLabel} doesn't allow replies from the car."))
+            lingerThenIdle(id)
+            return
+        }
+        // Android hands every app but the dialer a silent microphone during a call.
+        if (CarCalls.state.value is CallUiState.Active) {
+            val id = begin(State(Phase.ERROR, n, error = "Voice reply works once the call ends."))
+            lingerThenIdle(id)
+            return
+        }
+        if (!readFirst) {
+            val id = begin(State(Phase.ASKING, n))
+            ask(id)
+            return
+        }
+        // Read it, then "Do you want to reply?", the same as Read.
+        read(n)
+    }
+
+    private fun ask(id: Int) {
+        CarAssistant.say("What's your reply?") {
+            if (id == run) listen(id)
+        }
+    }
+
+    private fun listen(id: Int) {
+        _state.value = _state.value.copy(phase = Phase.LISTENING, heard = "")
+        CarAssistant.dictate(
+            onPartial = { text -> if (id == run) _state.value = _state.value.copy(heard = text) },
+            onResult = { text -> if (id == run) confirm(id, text) },
+            onError = { message ->
+                if (id != run) return@dictate
+                _state.value = _state.value.copy(phase = Phase.ERROR, error = message)
+                lingerThenIdle(id)
+            },
+        )
+    }
+
+    private fun confirm(id: Int, text: String) {
+        _state.value = _state.value.copy(phase = Phase.CONFIRMING, heard = text, until = 0L, span = 0L, held = 0f)
+        // The countdown starts once the driver has heard the whole reply, not while it's read out.
+        CarAssistant.say("Sending: $text") {
+            if (id != run) return@say
+            startCountdown(id, SEND_DELAY_MS)
+            // A moment for the read-back to finish playing in the car before the microphone opens.
+            main.postDelayed({ if (id == run) listenForCommand(id) }, ECHO_MS)
+        }
+    }
+
+    /** Sends in [ms]. */
+    private fun startCountdown(id: Int, ms: Long) {
+        val sendAt = SystemClock.uptimeMillis() + ms
+        _state.value = _state.value.copy(until = sendAt, span = ms, held = 0f)
+        main.removeCallbacksAndMessages(SEND_TOKEN)
+        main.postAtTime({ if (id == run) send() }, SEND_TOKEN, sendAt)
+    }
+
+    /**
+     * Listens through the countdown for "cancel", "change it" or "send". The countdown never
+     * pauses: in a noisy car it held for road noise and the radio, and the reply never went.
+     */
+    private fun listenForCommand(id: Int) {
+        CarAssistant.dictate(
+            onPartial = {},
+            cue = false,
+            onResult = { text ->
+                if (id != run) return@dictate
+                when (command(text)) {
+                    Command.CANCEL -> {
+                        close()
+                        CarAssistant.say("Not sent.") {}
+                    }
+                    Command.CHANGE -> {
+                        main.removeCallbacksAndMessages(SEND_TOKEN)
+                        _state.value = _state.value.copy(phase = Phase.ASKING, heard = "", until = 0L, span = 0L, held = 0f)
+                        ask(id)
+                    }
+                    Command.SEND -> send()
+                    // Talk that wasn't meant for us, a passenger or the radio: keep listening, so a
+                    // "cancel" after it still lands before the countdown runs out.
+                    null -> listenForCommand(id)
+                }
+            },
+            // Silence ends the recognizer before the countdown does: listen again until it sends.
+            onError = {
+                if (id != run) return@dictate
+                // A short gap, so a recognizer that fails at once can't spin.
+                main.postDelayed({ if (id == run) listenForCommand(id) }, RELISTEN_MS)
+            },
+        )
+    }
+
+    private enum class Command { CANCEL, CHANGE, SEND }
+
+    private fun command(text: String): Command? {
+        val words = words(text)
+        return when {
+            words.any { it in CANCEL_WORDS } -> Command.CANCEL
+            words.any { it in CHANGE_WORDS } -> Command.CHANGE
+            words.any { it in SEND_WORDS } -> Command.SEND
+            else -> null
+        }
+    }
+
+    private fun words(text: String) = text.lowercase().split(Regex("[^a-z']+")).filter { it.isNotEmpty() }
+
+    /**
+     * Ready-made replies for a tap instead of a voice reply. The first gives the arrival time when
+     * the map is following a route.
+     */
+    fun quickReplies(): List<String> = listOfNotNull(etaReply(), "Driving, I'll reply soon.", "On my way.")
+
+    private fun etaReply(): String? {
+        val estimate = (CarServices.nav.template.value as? NavigationTemplate)?.destinationTravelEstimate ?: return null
+        val at = estimate.arrivalTimeAtDestination.clockTime()
+        val left = remainingTime(estimate.remainingTimeSeconds)
+        return when {
+            at.isNotEmpty() -> "Driving, I'll be there around $at."
+            left.isNotEmpty() -> "Driving, I'll be there in about $left."
+            else -> null
+        }
+    }
+
+    /** Sends [text] to [n] straight away, as if it had been said and confirmed. */
+    fun quickReply(n: CarNotification, text: String) {
+        if (n.reply == null) return
+        begin(State(Phase.CONFIRMING, n, heard = text))
+        send()
+    }
+
+    /** Sends a reply that's counting down, without waiting for the rest of it. */
+    fun sendNow() {
+        if (_state.value.phase == Phase.CONFIRMING) send()
+    }
+
+    private fun send() {
+        val s = _state.value
+        val n = s.target ?: return finish()
+        val context = appContext ?: return finish()
+        val id = ++run
+        CarAssistant.stopListening()
+        CarAssistant.stopSpeaking()
+        if (CarNotifications.reply(context, n, s.heard.trim())) {
+            GearslipLog.i("voice reply: sent to ${n.appLabel}")
+            CarAssistant.say("Message sent.") {}
+            CarNotifications.dismissPopup(n.id)
+            _state.value = s.copy(phase = Phase.SENT, until = SystemClock.uptimeMillis() + SENT_MS, span = SENT_MS, held = 0f)
+            main.postDelayed({ if (id == run) finish() }, SENT_MS)
+        } else {
+            _state.value = s.copy(phase = Phase.ERROR, error = "${n.appLabel} withdrew the reply. Open the app on the phone to answer.")
+            lingerThenIdle(id)
+        }
+    }
+
+    /** Stops wherever it is. Nothing is sent, and the message card closes. */
+    fun cancel() {
+        if (!active) return
+        CarAssistant.stopListening()
+        CarAssistant.stopSpeaking()
+        close()
+    }
+
+    /**
+     * Ends without sending and takes the message card with it. Without this the card's own popup
+     * came back with a fresh bar, as if the message had just arrived.
+     */
+    private fun close() {
+        _state.value.target?.let { CarNotifications.dismissPopup(it.id) }
+        finish()
+    }
+
+    /**
+     * The steering wheel's voice key. With a message on screen it answers that message, and
+     * during a countdown it sends straight away. Returns false when there's nothing to answer, so
+     * the key can start the assistant instead.
+     */
+    fun onVoiceKey(): Boolean {
+        val s = _state.value
+        when (s.phase) {
+            // Already heard, so straight to the reply.
+            Phase.READ, Phase.READING, Phase.OFFERING, Phase.ERROR -> s.target?.let { reply(it, readFirst = false); return true }
+            Phase.CONFIRMING -> { sendNow(); return true }
+            Phase.ASKING, Phase.LISTENING, Phase.SENT -> return true
+            Phase.IDLE -> Unit
+        }
+        val popup = CarNotifications.popup.value ?: return false
+        if (popup.reply == null) return false
+        reply(popup)
+        return true
+    }
+
+    private fun begin(state: State): Int {
+        CarAssistant.stopListening()
+        CarAssistant.stopSpeaking()
+        main.removeCallbacksAndMessages(null)
+        _state.value = state
+        return ++run
+    }
+
+    private fun lingerThenIdle(id: Int) {
+        _state.value = _state.value.copy(until = SystemClock.uptimeMillis() + LINGER_MS, span = LINGER_MS, held = 0f)
+        main.postDelayed({ if (id == run) finish() }, LINGER_MS)
+    }
+
+    private fun finish() {
+        run++
+        main.removeCallbacksAndMessages(null)
+        _state.value = State()
+    }
+
+    /** "Alex says: ..." or, in a group, "Sam in Climbing says: ...", for the newest messages. */
+    private fun spoken(n: CarNotification): String {
+        val from = n.title.ifBlank { n.appLabel }
+        val lines = n.lines.filter { it.sender != null }.takeLast(n.burst.coerceIn(1, MAX_READ))
+        if (lines.isEmpty()) return "$from says: ${n.text}"
+        return lines.joinToString(". ") { line ->
+            val who = if (n.isGroup) "${line.sender} in $from" else from
+            "$who says: ${line.text}"
+        }
+    }
+
+    private const val MAX_READ = 3
+    private val YES_WORDS = setOf("yes", "yeah", "yep", "yup", "sure", "ok", "okay", "reply", "please")
+    private val NO_WORDS = setOf("no", "nope", "nah", "cancel", "don't", "stop")
+    private val CANCEL_WORDS = setOf("cancel", "stop", "don't", "no", "nope")
+    private val CHANGE_WORDS = setOf("change", "redo", "again", "edit", "wrong", "fix")
+    private val SEND_WORDS = setOf("send", "yes", "yeah", "ok", "okay", "go")
+
+    private val SEND_TOKEN = Any()
+    private const val ECHO_MS = 300L
+    /** How long "Do you want to reply?" waits for an answer: the start beep, then the engine's silence limit. */
+    private const val OFFER_MS = 6_500L
+    private const val OFFER_GRACE_MS = 1_500L
+    private const val RELISTEN_MS = 400L
+}