Apps can say they work with Gearslip, and each recommended app gets its own page

An app adds one meta-data line to its manifest and Gearslip marks it Works with Gearslip in the
Recommended apps list. Tapping an app opens its page, with an Open or Get button. A README badge
for app developers is in docs/badge, documented in BUILDING_APPS.md.

.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: seb3thehacker
+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

@@ -5,7 +5,7 @@ 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.
+        Thanks for reporting. Check the [open issues](https://github.com/twinksoftware/gearslip/issues) first, in case someone has already reported it.
 
   - type: input
     id: car
@@ -16,6 +16,15 @@ body:
     validations:
       required: true
 
+  - type: input
+    id: version
+    attributes:
+      label: Gearslip version
+      description: Shown under the Gearslip name on the app's home screen.
+      placeholder: v0.3.40-alpha
+    validations:
+      required: true
+
   - type: dropdown
     id: head-unit
     attributes:

.github/ISSUE_TEMPLATE/car_report.yml

@@ -16,6 +16,15 @@ body:
     validations:
       required: true
 
+  - type: input
+    id: version
+    attributes:
+      label: Gearslip version
+      description: Shown under the Gearslip name on the app's home screen.
+      placeholder: v0.3.40-alpha
+    validations:
+      required: true
+
   - type: dropdown
     id: head-unit
     attributes:

.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 +1,13 @@
+Gearslip 0.3.40 is a test build for a few cars that still don't connect.
+
+If your car works on 0.3.39, you don't need this one. If you're following #18, #39 or #57, please try it and attach a log to your issue: open Gearslip, tap Logs, then Share log.
+
+## Fixed
+- A car that holds back its screen is asked for it again with the detail older cars expect. This is for the 2017 Pilot (#57) and other cars on the oldest Android Auto version.
+- Music no longer carries on from the phone's speaker after you turn the car off. An app that started playing again by itself is paused a second time (#39).
+- A liked song lights up the whole like button, as shuffle and repeat do. Before, only the heart filled in for apps such as Metrolist.
+
+## Testing
+- GM cars open two more channels, Bluetooth and Wi-Fi projection, and log what the car sends on them. This is to find out why the 2021 Bolt hangs up about 20 seconds in (#18). If you drive a GM car, type your phone's Bluetooth address under Settings > Connection > Phone's Bluetooth address. You'll find it in Android's Settings under About phone.
+
+Help translate Gearslip on [Weblate](https://hosted.weblate.org/engage/gearslip/).

.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

@@ -12,6 +12,9 @@ jobs:
       contents: write
     steps:
       - uses: actions/checkout@v4
+        with:
+          # The build names itself after the newest tag, which a shallow clone doesn't have.
+          fetch-depth: 0
 
       - uses: actions/setup-java@v4
         with:
@@ -45,4 +48,9 @@ jobs:
         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/translations.yml

@@ -0,0 +1,20 @@
+name: Translations
+
+# Weblate is the only thing that writes translated strings: it pushes straight to experimental,
+# never through a pull request. A PR that edits them collides with Weblate's own copy, and
+# Weblate locks itself until someone resets it. Edit the English strings.xml only.
+# Weblate's own pull requests are the exception: they are the translations.
+on:
+  pull_request:
+    paths:
+      - "gearslip/src/main/res/values-*/strings.xml"
+
+jobs:
+  weblate-only:
+    if: github.event.pull_request.user.login != 'weblate'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Translations go through Weblate
+        run: |
+          echo "::error::This pull request edits a translation. Please make translation changes on Weblate instead: https://hosted.weblate.org/engage/gearslip/ (it can upload a whole strings.xml under Files > Upload translation). See CONTRIBUTING.md."
+          exit 1

.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

@@ -11,7 +11,7 @@ local.properties
 *.keystore
 keystore.properties
 
-# Native build cache.
+# Native build cache
 .cxx/
 
 # Testing
@@ -29,4 +29,12 @@ CLAUDE.md
 
 # Other
 archive/
-.wrangler/
+.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 +1,50 @@
+# 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) |
+| Renault Clio V | 2019-2024 | Easy Link |
+| 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 +1,105 @@
+# 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.
+
+Translators sign on Weblate: it shows this agreement before your first translation, and
+accepting it there 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

@@ -5,7 +5,7 @@ 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:
+Open an issue on [GitHub](https://github.com/twinksoftware/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.
@@ -38,6 +38,24 @@ branch on `experimental`, and open your pull request against it.
 - Gearslip asks for no adb, root, or Shizuku. A feature must work with ordinary Android
   permissions and on-device consent dialogs.
 
+## Translating
+
+Translations happen on [Weblate](https://hosted.weblate.org/engage/gearslip/), never in pull
+requests. Pick your language, or start a new one, and translate in the browser. Weblate
+sends the finished work to this repository as a pull request.
+
+Don't edit the translated `values-*/strings.xml` files by hand. Weblate keeps its own copy of
+every language, so a change made in git collides with Weblate's next update, and the pull
+request that made it gets closed. If a code change adds or rewords text, change only the
+English file, `values/strings.xml`; Weblate picks up the new strings for translators.
+
+Keep the tone of the English: short, plain, and friendly. Leave placeholders such as `%1$s`
+and `%1$d` in place; Gearslip fills them with names and numbers. Untranslated strings show
+in English, so a partial translation is still useful.
+
+Before your first translation, Weblate asks you to accept the
+[Contributor License Agreement](CLA.md). That counts as signing it.
+
 ## Writing
 
 Text that users read, such as screens, release notes, and docs, follows Strunk's
@@ -46,6 +64,10 @@ 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. The author also sells a
-commercial license, described in [NOTICE.md](NOTICE.md). By opening a pull request, you
-agree that your contribution may be offered under that license as well.
+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.

LICENSE

@@ -1,4 +1,4 @@
-Copyright (C) 2026 seb
+Copyright (C) 2026 Twink Software LLC and contributors
 
                     GNU AFFERO GENERAL PUBLIC LICENSE
                        Version 3, 19 November 2007

NOTICE.md

@@ -6,4 +6,4 @@ You may use, run, and modify Gearslip freely. If you distribute a modified versi
 
 ## Commercial licensing
 
-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.
+If the AGPL's terms don't work for you, Twink Software LLC, which owns Gearslip, 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 us on Matrix; the address is on the [Seb3thehacker GitHub profile](https://github.com/Seb3thehacker).

README.md

@@ -4,75 +4,120 @@
 
 An Android Auto alternative built for everyone.
 
-## What Gearslip is
+[<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/twinksoftware/gearslip)
 
-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.
+![Vela Maps navigating on the car screen, with the music player beside the map](docs/screenshots/navigation.png)
+
+[![forthebadge](https://forthebadge.com/badges/compatibility-club-penguin.svg)](https://forthebadge.com)
+
+Gearslip speaks the Android Auto protocol straight to your car, over USB or wireless, with no
+Google software in the path. Map, music, and messaging apps draw their car screens through
+Gearslip, and it adds a player, calls, voice, and a web browser of its own.
+
+> [!WARNING]
+> Gearslip is **alpha software**. It can drop the connection, freeze the car screen, or fail
+> to start, and a new release can break a car that worked before. Set it up while parked, and
+> keep another way to navigate.
+
+Questions, ideas? [Join the discussion on Matrix](https://matrix.to/#/!mf0_mgBd5KqKpc9FfX_wHp1jFCcwAtPrndIn_oGIyMk?via=matrix.org).
+
+## What works
 
 | | |
 |---|---|
-| ![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. |
+| **Cars** | Most cars, over USB or wireless. Some cars from about 2020 on need a certificate of your own. [CARS.md](CARS.md) lists the cars drivers have confirmed. |
+| **Maps** | Organic Maps, Vela, OsmAnd, Waze, Flitsmeister, MAPS.ME, and MapQuest on the car screen, alerts included. Turns from Google Maps or Waze on the phone show in the nav bar and on the instrument cluster. |
+| **Music** | Any app built for car screens, with Now Playing, Up Next, search, and lyrics. Spotify plays through Gearslip's own player. |
+| **Calls** | Dial or search contacts, and answer or decline on the car screen. Calls use the car's Bluetooth. |
+| **Messages** | Read aloud on arrival, with a reply by voice or a quick reply. |
+| **Voice** | "Navigate to the nearest gas station", "play Daft Punk", "call Mom". Speech stays on the phone. Commands are in English for now. |
+| **Controls** | Touch, steering wheel buttons, control knobs, and D-pads. |
+| **Languages** | English and 19 more, some only partly translated. |
+| **Head units with Android** | Gearslip can be the home screen of an Android head unit, or of a spare phone or tablet on the dash. Turn on Use as launcher in Settings > Connection. |
+| **Doesn't work** | Spotify's and Google Messages' own car screens, which accept only Android Auto. TIDAL lets only approved apps browse its library. |
+
+## See it
+
+| | |
+|---|---|
+| ![The launcher, with every car app on the phone](docs/screenshots/launcher.png) | ![Metrolist's song, art, and controls in Gearslip's player](docs/screenshots/music.png) |
+| Your car apps in one place. | Metrolist in Gearslip's player. |
+| ![A new message card over Vela Maps](docs/screenshots/message.png) | ![Synced lyrics beside the player, lit up to the word being sung](docs/screenshots/lyrics.png) |
+| A new message, read aloud at a tap, over the map. | Lyrics light up word by word as the song plays. |
+| ![The voice assistant listening over Vela Maps](docs/screenshots/assistant.png) | ![Three routes to a coffee shop in Vela Maps, each with its time and distance](docs/screenshots/places.png) |
+| Ask for a place, a song, or an app. | Pick a route. Each one shows its time and distance. |
+| ![DuckDuckGo open in Gearslip's web browser](docs/screenshots/web.png) | |
+| Browse the web while parked. | |
 
 ## Features
 
-- **Phone calls.** Dial from a keypad, or search your contacts, then confirm before the
-  call goes out.
-- **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.
-- **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.
+- **Navigation.** Gearslip hosts real map apps on the car screen. While you navigate, a big
+  turn card shows the arrow, the distance, and your lane, and the map keeps the rest.
+- **Music.** Browse, play, and queue from any car-ready media app. Type a search, and apps
+  that accept one play the best match.
+- **Phone calls.** During a call, the nav bar shows who you're talking to, and you mute or
+  hang up from there.
+- **Messages and notifications.** Only messages, missed calls, alarms, and reminders
+  interrupt you. The rest wait on the dashboard. Music pauses while Gearslip speaks or
+  listens.
+- **Voice.** Tap the mic or press the talk button on the wheel. Say "help" for the full list.
+- **The web.** A browser with an address bar, back and forward, and its own keyboard.
+- **Weather and the day ahead.** A dashboard shows the week's calendar beside the weather.
+- **Your apps, your order.** Apps group by kind. Press and hold one to move it, and hide
+  the ones you don't use from the Apps card on the phone.
+- **Your look.** The car screen takes your phone's Material You colors. Choose flat
+  buttons or ones that look like real keys, and make text bigger on small screens.
+- **Settings on the phone.** Set things up before you drive. A change on either screen
+  shows on both.
 
-## Status
+## Install
 
-- **The connection is wired only, for now.** Plug the phone into the head unit's USB port;
-  Gearslip does not yet offer a wireless option.
-- **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, sign-in, and text fields.
-  It has been tested against several real navigation and media apps.
+1. Install Gearslip from [the releases page](https://github.com/twinksoftware/Gearslip/releases)
+   or through Obtainium.
+2. Open it. Setup asks where your Android Auto certificate comes from, then for one
+   permission at a time, each with a plain reason. A help screen in the car answers the rest.
+3. Plug the phone into the car's USB port. In a car with wireless Android Auto, pair the
+   phone with the car over Bluetooth, then tap Connect wirelessly and pick the car.
+
+After the first wireless drive, Android asks once whether Gearslip may watch for that car.
+From then on, Gearslip connects whenever the car's Bluetooth does.
+
+> [!NOTE]
+> On GrapheneOS, make sure **USB-C port control** isn't set to **Charging-only**. That
+> setting blocks USB data, so the car never sees the phone, even with a data cable.
+
+Gearslip updates itself from this repository. Once a day it checks the latest release,
+downloads the APK, checks it against GitHub's SHA-256, and installs it through Android's
+own installer. Turn off automatic checks in Settings.
+
+### Verify your download
+
+Check that your copy of Gearslip is genuine with
+[AppVerifier](https://github.com/soupslurpr/AppVerifier): share this block to it, or compare it
+with the output of `apksigner verify --print-certs`.
+
+```
+app.seb3thehacker.gearslip
+4C:C5:6E:BD:D1:3A:54:D2:60:EC:A9:B7:E2:B2:AE:6B:30:E2:F2:25:BF:DA:8F:50:8F:07:09:ED:F0:84:94:8B
+```
+
+## Good to know
+
+- **Music reaches the car over Bluetooth or through Gearslip.** Setup asks which.
+  Bluetooth is the default. Android never asks for permission, and your map app's voice
+  reaches the car too. Through Gearslip, the sound travels over the car connection, cable
+  or wireless. It sounds a little clearer, with no delay, but each drive Android asks you
+  to share your screen, which lets Gearslip send the sound. 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. For audio through Gearslip, setup
+  offers two optional adb commands. One removes the audio dialog for good, and the other
+  keeps notifications visible while audio plays.
+- **Apps without a car screen** can still reach the car through a separate screen-sharing
+  mode.
 - **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.
-- **Gearslip works best with cars from before 2020.** Some newer head units reject its
-  certificate.
-- **Calls use the car's Bluetooth,** as they do in Android Auto. Pair the phone with the
-  car to hear calls through its speakers.
-- **Audio reaches the car by capturing playback, not by mirroring the screen.** Android
-  shows a screen-share consent dialog for this, even though Gearslip never reads the
-  screen; it is the only way an ordinary app can capture another app's audio. The dialog
-  appears once per drive.
-- **Gearslip needs no adb, root, or Shizuku.** Every feature relies on an ordinary
-  Android permission or an on-device consent dialog. The setup guide offers two optional
-  adb commands: one removes the audio dialog for good, and the other keeps notifications
-  visible while audio plays.
 
 ## Usage notes
 
@@ -81,20 +126,44 @@ 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, plus whatever you tick: 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.
-  Settings shows the exact note.
+- **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 through Gearslip or over 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 a Cloudflare Worker, whose code is in
-  [stats-worker/](stats-worker/). Cloudflare sees your IP address in delivering a note,
-  as it would for any website; the Worker doesn't store 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.
 
+## Help out
+
+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.
+
+To translate Gearslip into your language, join
+[Gearslip on Weblate](https://hosted.weblate.org/engage/gearslip/). No coding needed.
+Translations go through Weblate only, since it holds its own copy of every language and
+changes made in git collide with it.
+
+[![Translation status by language](https://hosted.weblate.org/widget/gearslip/app/multi-auto.svg)](https://hosted.weblate.org/engage/gearslip/)
+
+## 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.
+
 ## Building
 
 ```
@@ -113,6 +182,17 @@ 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
@@ -121,5 +201,6 @@ 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
-commercial license for private use outside the AGPL's terms; see [NOTICE.md](NOTICE.md).
+Gearslip belongs to Twink Software LLC and is licensed under AGPL-3.0; see [LICENSE](LICENSE).
+The LLC also sells a separate commercial license for private use outside the AGPL's terms; see
+[NOTICE.md](NOTICE.md).

docs/BUILDING_APPS.md

@@ -469,6 +469,44 @@ home-screen pane comes later. Anything that needs its own rendering belongs in a
 
 ---
 
+## Works with Gearslip
+
+Once your app runs well on Gearslip, say so in two places: your manifest and your README.
+
+### In your manifest
+
+Add these lines to `<application>`:
+
+```xml
+<meta-data
+    android:name="app.seb3thehacker.gearslip.works_with"
+    android:value="true" />
+<meta-data
+    android:name="app.seb3thehacker.gearslip.about"
+    android:resource="@string/gearslip_about" />
+```
+
+Gearslip then marks your app "Works with Gearslip" in its Recommended apps list and on your app's
+page in Gearslip. An installed app with the flag gets its own place at the top of the list.
+
+The second entry is optional. It gives your page one sentence on what your app does in the car,
+such as "Spots trackers and cameras nearby." Write it in place with `android:value` if you have no
+string resource for it.
+
+The flag is a label. Gearslip finds and runs your app the same way with or without it.
+
+### In your README
+
+Add the badge:
+
+```markdown
+[![Works with Gearslip](https://raw.githubusercontent.com/twinksoftware/gearslip/main/docs/badge/works-with-gearslip.svg)](https://github.com/twinksoftware/gearslip)
+```
+
+It matches the flat badges most READMEs already show.
+
+---
+
 ## Further reading
 
 - [README.md](../README.md) - what Gearslip is.

docs/badge/works-with-gearslip.svg

@@ -0,0 +1,16 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="147" height="20" role="img" aria-label="Works with Gearslip">
+  <title>Works with Gearslip</title>
+  <clipPath id="r"><rect width="147" height="20" rx="3" fill="#fff"/></clipPath>
+  <g clip-path="url(#r)">
+    <rect width="88" height="20" fill="#555"/>
+    <rect x="88" width="59" height="20" fill="#8C1F1F"/>
+  </g>
+  <g transform="translate(5 3.5) scale(0.228) translate(-29.5 -25.5)" fill="#fff">
+    <path fill-rule="evenodd" d="M54 36.18 58.64 30.7 67.2 34.24 66.6 41.4 71.82 54 77.3 58.64 73.76 67.2 66.6 66.6 67.2 73.76 58.64 77.3 54 71.82 49.36 77.3 40.8 73.76 41.4 66.6 34.24 67.2 30.7 58.64 36.18 54 30.7 49.36 34.24 40.8 41.4 41.4 40.8 34.24 49.36 30.7ZM54 46.08A7.92 7.92 0 1 1 53.99 46.08Z"/>
+    <path d="M78.61 40.7 85.31 43.29 84.74 52.55 77.78 54.31Z"/>
+  </g>
+  <g fill="#fff" font-family="Verdana,Geneva,DejaVu Sans,sans-serif" font-size="11" text-rendering="geometricPrecision">
+    <text x="22" y="14" textLength="60">works with</text>
+    <text x="94" y="14" textLength="47">Gearslip</text>
+  </g>
+</svg>

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

@@ -24,6 +24,42 @@ val keystoreProperties = Properties().apply {
     ).firstOrNull { it.exists() }?.inputStream()?.use { load(it) }
 }
 
+// The version comes from the newest v* git tag, so a build can never disagree with its tag. A
+// build of the tagged commit is named after it ("0.4.0-beta"); anything later adds the commits
+// since and the commit ("0.4.0-beta+3.ba4374e"), so a test build can't pass for a release.
+// The version code is worked out from the numbers, ((major*100 + minor)*100 + patch)*10 + stage,
+// where stage is 1 for alpha, 2 for beta and 9 for a finished release. It only ever goes up as
+// long as minor and patch stay under 100. Changelog entries use the same number.
+class GitVersion(val name: String, val code: Int)
+
+val gitVersion: GitVersion = run {
+    val described = runCatching {
+        providers.exec {
+            commandLine("git", "describe", "--tags", "--match", "v*", "--abbrev=7")
+            isIgnoreExitValue = true
+        }.standardOutput.asText.get().trim()
+    }.getOrNull().orEmpty()
+    val match = Regex("""^v((\d+)\.(\d+)\.(\d+)(?:-([A-Za-z]+))?)(?:-(\d+)-g([0-9a-f]+))?$""").find(described)
+        ?: return@run GitVersion("0.0.0-dev", 1) // no git or no tags, e.g. a source download
+    val (base, major, minor, patch, suffix, since, commit) = match.destructured
+    val stage = when (suffix.lowercase()) {
+        "" -> 9
+        "beta" -> 2
+        "alpha" -> 1
+        else -> 0
+    }
+    GitVersion(
+        name = if (since.isEmpty()) base else "$base+$since.$commit",
+        code = ((major.toInt() * 100 + minor.toInt()) * 100 + patch.toInt()) * 10 + stage,
+    )
+}
+
+// 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
@@ -32,8 +68,9 @@ android {
         applicationId = "app.seb3thehacker.gearslip"
         minSdk = 31
         targetSdk = 37
-        versionCode = 8
-        versionName = "0.2.00-alpha"
+        versionCode = gitVersion.code
+        // -PgearslipVersionName=0.1.99-test makes a build that thinks it's older, to try the updater.
+        versionName = project.findProperty("gearslipVersionName")?.toString() ?: gitVersion.name
         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.
@@ -56,14 +93,27 @@ 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 dev build installs beside the release one instead of over it.
+        // 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 Dev"
+            manifestPlaceholders["appLabel"] = "Gearslip Debug"
+            // English (XA) and Arabic (XB) under the phone's languages: stretched, accented and
+            // right-to-left text, which shows what's still hardcoded and what doesn't fit.
+            isPseudoLocalesEnabled = true
+            // Shrunk with R8 like a release, so a debug install behaves like what ships (a keep
+            // rule missing for release shows up here first). -PnoR8 skips it for a quicker build.
+            if (!project.hasProperty("noR8")) {
+                isMinifyEnabled = true
+                isShrinkResources = true
+                proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
+            }
         }
     }
 
@@ -71,10 +121,24 @@ android {
         buildConfig = true
     }
 
-    // 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"))
+    // Lists each language that has a translation in the app's locale config, so Android 13+
+    // offers it under the system's per-app languages. English is the unqualified default
+    // (res/resources.properties).
+    //
+    // Only languages that are mostly translated ship, so the app never comes up half in English.
+    // Danish and Estonian are still early on Weblate; add them here once they're close to done.
+    androidResources {
+        generateLocaleConfig = true
+        localeFilters += listOf(
+            "en", "ar", "cs", "de", "es", "fr", "it", "ja", "ko", "nl", "pl", "pt-rBR", "ro", "ru",
+            "sv", "tr", "uk", "zh-rCN",
+        )
+    }
+
+    lint {
+        // Weblate fills languages in a string at a time; the rest fall back to English.
+        disable += "MissingTranslation"
+    }
 
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_21
@@ -82,22 +146,16 @@ android {
     }
 
     defaultConfig {
-        // Speech-to-text 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" }
-    }
-    ndkVersion = "27.1.12297006"
-    externalNativeBuild {
-        cmake {
-            path = file("src/main/cpp/CMakeLists.txt")
-            version = "3.22.1"
-        }
-    }
-    androidResources {
-        // Model weights barely compress, and stored plainly they stream straight out of the APK.
-        noCompress += "bin"
+        // Speech-to-text (sherpa-onnx 1.13.8, static-link-onnxruntime build, in jniLibs) is the
+        // only native code. One APK for all three, since the updater takes the release's only APK;
+        // 32-bit x86 is left out, nothing that drives a car runs it.
+        ndk { abiFilters += listOf("arm64-v8a", "armeabi-v7a", "x86_64") }
     }
 
+    // Compressed, the three copies cost a 33 MB download instead of 75 MB; the phone unpacks
+    // only its own at install.
+    packaging { jniLibs { useLegacyPackaging = true } }
+
     testOptions {
         // GearslipLog calls android.util.Log, which is a stub on the local JVM.
         unitTests.isReturnDefaultValues = true
@@ -105,9 +163,10 @@ android {
 
 }
 
-// Renames the produced APK and moves it to the root build/ folder (<root>/build/Gearslip-debug.apk)
-// after the fact rather than fighting AGP's variant-output API across versions - simpler and
-// doesn't break when that API moves again.
+// Copies the produced APK to the root build/ folder (<root>/build/Gearslip-debug.apk) after the
+// fact rather than fighting AGP's variant-output API across versions - simpler and doesn't break
+// when that API moves again. A copy, not a move: AGP packages incrementally into the APK it left
+// last time, and with that file gone a build came out holding nothing but classes.dex.
 tasks.register("renameApk") {
     doLast {
         val rootBuildDir = rootProject.layout.buildDirectory.get().asFile
@@ -117,7 +176,6 @@ tasks.register("renameApk") {
             .forEach { apk ->
                 val renamed = File(rootBuildDir, "Gearslip-${apk.parentFile.name}.apk")
                 apk.copyTo(renamed, overwrite = true)
-                apk.delete()
             }
     }
 }
@@ -138,6 +196,10 @@ dependencies {
     implementation(libs.androidx.car.app)
     implementation(libs.androidx.car.app.projected)
     implementation(libs.androidx.media)
+    // Document-start scripts, so the ad blocker hides ad slots before a page first paints.
+    implementation(libs.androidx.webkit)
+    // The map behind a place list (PlaceListMapTemplate), which the host draws, not the app.
+    implementation(libs.maplibre.android)
     testImplementation(libs.junit)
 }
 

gearslip/proguard-rules.pro

@@ -0,0 +1,13 @@
+# 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.** { *; }

gearslip/src/main/AndroidManifest.xml

@@ -4,6 +4,9 @@
 
     <!-- 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" />
+    <!-- Lets an update Gearslip installed itself skip Android's prompt. -->
+    <uses-permission android:name="android.permission.UPDATE_PACKAGES_WITHOUT_USER_ACTION" />
 
     <!--
       Phone mirroring. Android refuses to hand over a MediaProjection unless a foreground
@@ -18,6 +21,27 @@
     <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" />
+    <!-- Keeps a wireless start going with the phone locked; see WirelessKeepAlive. -->
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_CONNECTED_DEVICE" />
+
+    <!--
+        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" />
+    <!-- Wireless auto-connect: Android tells Gearslip when a car it manages connects. -->
+    <uses-permission android:name="android.permission.REQUEST_OBSERVE_COMPANION_DEVICE_PRESENCE" />
+    <uses-feature android:name="android.software.companion_device_setup" android:required="false" />
+    <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" />
@@ -42,7 +66,8 @@
 
     <!--
         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
+        call's own state (ringing, in progress) and the incoming number need, and READ_CALL_LOG
+        also lists recent calls on the car's Phone screen, read on the phone only; 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.
@@ -74,8 +99,10 @@
          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" />
-    <!-- Every GrapheneOS install has this; the opt-in usage note uses it to say "GrapheneOS". -->
+    <!-- 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" />
@@ -104,6 +131,7 @@
         android:roundIcon="@mipmap/ic_launcher"
         android:label="${appLabel}"
         android:supportsRtl="true"
+        android:manageSpaceActivity="app.seb3thehacker.gearslip.ui.ManageSpaceActivity"
         android:theme="@style/Theme.Gearslip">
 
         <provider
@@ -135,11 +163,58 @@
 
         </activity>
 
+        <!--
+          Launcher mode: the car UI as this device's home screen, for a head unit that runs Android
+          or a tablet on the dash. Off until Settings turns it on (LauncherMode), so phones never
+          list Gearslip as a home app.
+        -->
+        <activity
+            android:name=".LauncherActivity"
+            android:enabled="false"
+            android:exported="true"
+            android:launchMode="singleTask"
+            android:excludeFromRecents="true"
+            android:screenOrientation="sensorLandscape"
+            android:configChanges="orientation|screenSize|screenLayout|smallestScreenSize|keyboardHidden|uiMode|density|locale|layoutDirection|fontScale">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.HOME" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </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.
         -->
+        <!-- App info › Storage › Manage space: clears lyrics, voice models and logs one at a time. -->
+        <!-- "Share" a page from any browser to add it to the car browser's start page (issue #85). -->
+        <activity
+            android:name=".browser.ShareToBrowserActivity"
+            android:exported="true"
+            android:excludeFromRecents="true"
+            android:label="@string/browser_share_label"
+            android:noHistory="true"
+            android:theme="@android:style/Theme.Translucent.NoTitleBar">
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/plain" />
+            </intent-filter>
+        </activity>
+
+        <activity
+            android:name=".ui.ManageSpaceActivity"
+            android:exported="true"
+            android:label="Gearslip storage" />
+
+        <activity
+            android:name=".PermissionActivity"
+            android:exported="false"
+            android:excludeFromRecents="true"
+            android:theme="@style/Theme.Gearslip.Invisible" />
+
         <activity-alias
             android:name=".GearslipUsbAccessory"
             android:targetActivity=".GearslipActivity"
@@ -159,6 +234,14 @@
             android:name=".notify.TestMessageReceiver"
             android:exported="false" />
 
+        <receiver
+            android:name=".update.UpdateReceiver"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="android.intent.action.MY_PACKAGE_REPLACED" />
+            </intent-filter>
+        </receiver>
+
         <service
             android:name=".mirror.MirrorService"
             android:exported="false"
@@ -169,6 +252,11 @@
             android:exported="false"
             android:foregroundServiceType="location" />
 
+        <service
+            android:name=".wireless.WirelessKeepAlive"
+            android:exported="false"
+            android:foregroundServiceType="connectedDevice" />
+
         <!--
           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.
@@ -225,5 +313,15 @@
                 <action android:name="android.telecom.CallScreeningService" />
             </intent-filter>
         </service>
+
+        <!-- Told when a car approved for wireless auto-connect comes up over Bluetooth. -->
+        <service
+            android:name=".wireless.CarPresenceService"
+            android:exported="true"
+            android:permission="android.permission.BIND_COMPANION_DEVICE_SERVICE">
+            <intent-filter>
+                <action android:name="android.companion.CompanionDeviceService" />
+            </intent-filter>
+        </service>
     </application>
 </manifest>

gearslip/src/main/cpp/CMakeLists.txt

@@ -1,36 +0,0 @@
-# Speech-to-text for voice replies and the assistant: whisper.cpp, pinned to one commit and
-# fetched at build time, so nothing outside this folder (cloned-repos included) is needed.
-cmake_minimum_required(VERSION 3.22)
-project(gearslip_speech CXX C)
-
-set(CMAKE_CXX_STANDARD 17)
-
-# Optimised in debug builds too. Unoptimised, Whisper runs several times slower, and a dev build
-# would make voice look far worse than what ships.
-foreach(lang C CXX)
-    set(CMAKE_${lang}_FLAGS_DEBUG "-O3 -DNDEBUG")
-endforeach()
-
-include(FetchContent)
-FetchContent_Declare(
-    whisper
-    URL https://github.com/ggml-org/whisper.cpp/archive/6e4ab854f67f743900934a703d5603419384c961.tar.gz
-    URL_HASH SHA256=55b585aec5e1bc03e2a5cea61da97c6406fa833996cf7daeed704972273cc039
-)
-
-set(BUILD_SHARED_LIBS OFF CACHE BOOL "" FORCE)
-set(WHISPER_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
-set(WHISPER_BUILD_TESTS OFF CACHE BOOL "" FORCE)
-set(WHISPER_BUILD_SERVER OFF CACHE BOOL "" FORCE)
-set(GGML_OPENMP OFF CACHE BOOL "" FORCE)
-set(GGML_NATIVE OFF CACHE BOOL "" FORCE)
-# ARMv8.2 with half floats and dot products: every phone that runs Android 12 or later in
-# practice, and what makes Whisper fast enough to answer in under a second.
-set(GGML_CPU_ARM_ARCH "armv8.2-a+dotprod+fp16" CACHE STRING "" FORCE)
-FetchContent_MakeAvailable(whisper)
-
-add_library(gearslip_speech SHARED speech_jni.cpp)
-target_compile_options(gearslip_speech PRIVATE -O3)
-find_library(LOG_LIB log)
-target_link_libraries(gearslip_speech whisper android ${LOG_LIB})
-target_link_options(gearslip_speech PRIVATE -Wl,--gc-sections -Wl,-z,max-page-size=16384)

gearslip/src/main/cpp/speech_jni.cpp

@@ -1,86 +0,0 @@
-// The bridge between Kotlin's SpeechEngine and whisper.cpp: load a model, turn one recorded
-// phrase into text, free the model. Recording and deciding when a phrase ends stay in Kotlin.
-
-#include <jni.h>
-#include <android/asset_manager.h>
-#include <android/asset_manager_jni.h>
-#include <android/log.h>
-#include <algorithm>
-#include <cmath>
-#include <string>
-#include "whisper.h"
-
-#define TAG "GearslipSpeech"
-#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, TAG, __VA_ARGS__)
-
-static whisper_context_params context_params() {
-    whisper_context_params p = whisper_context_default_params();
-    p.use_gpu = false;
-    return p;
-}
-
-// Streams a model straight out of the APK, so the bundled one is never copied to storage.
-static size_t asset_read(void *ctx, void *output, size_t size) {
-    int n = AAsset_read(static_cast<AAsset *>(ctx), output, size);
-    return n > 0 ? static_cast<size_t>(n) : 0;
-}
-static bool asset_eof(void *ctx) { return AAsset_getRemainingLength64(static_cast<AAsset *>(ctx)) <= 0; }
-static void asset_close(void *ctx) { AAsset_close(static_cast<AAsset *>(ctx)); }
-
-extern "C" JNIEXPORT jlong JNICALL
-Java_app_seb3thehacker_gearslip_speech_SpeechEngine_nativeInitAsset(JNIEnv *env, jobject, jobject assets, jstring jpath) {
-    AAssetManager *manager = AAssetManager_fromJava(env, assets);
-    const char *path = env->GetStringUTFChars(jpath, nullptr);
-    AAsset *asset = AAssetManager_open(manager, path, AASSET_MODE_STREAMING);
-    env->ReleaseStringUTFChars(jpath, path);
-    if (!asset) return 0;
-    whisper_model_loader loader = {asset, asset_read, asset_eof, asset_close};
-    return reinterpret_cast<jlong>(whisper_init_with_params(&loader, context_params()));
-}
-
-// Bytes, not a jstring: NewStringUTF wants modified UTF-8 and aborts on some of what Whisper can
-// write (four-byte characters), so Kotlin decodes the plain UTF-8 instead.
-extern "C" JNIEXPORT jbyteArray JNICALL
-Java_app_seb3thehacker_gearslip_speech_SpeechEngine_nativeTranscribe(
-    JNIEnv *env, jobject, jlong handle, jfloatArray jsamples, jstring jlang, jint threads) {
-    auto *ctx = reinterpret_cast<whisper_context *>(handle);
-    if (!ctx) return env->NewByteArray(0);
-    jsize n = env->GetArrayLength(jsamples);
-    jfloat *samples = env->GetFloatArrayElements(jsamples, nullptr);
-    const char *lang = env->GetStringUTFChars(jlang, nullptr);
-
-    whisper_full_params p = whisper_full_default_params(WHISPER_SAMPLING_GREEDY);
-    p.n_threads = threads;
-    p.language = lang;
-    p.translate = false;
-    p.no_context = true;
-    p.no_timestamps = true;
-    p.single_segment = true;
-    p.print_progress = false;
-    p.print_realtime = false;
-    p.print_special = false;
-    p.print_timestamps = false;
-    p.suppress_blank = true;
-    // The ACFT models are trained for a context cut to the audio's own length (1500 frames is
-    // 30 s, so 50 per second), which is what makes a three-second phrase fast. A little extra
-    // keeps the last word from being clipped.
-    p.audio_ctx = std::min(1500, static_cast<int>(std::ceil(n / 320.0)) + 32);
-
-    int rc = whisper_full(ctx, p, samples, n);
-    env->ReleaseStringUTFChars(jlang, lang);
-    env->ReleaseFloatArrayElements(jsamples, samples, JNI_ABORT);
-    if (rc != 0) {
-        LOGI("whisper_full failed: %d", rc);
-        return env->NewByteArray(0);
-    }
-    std::string text;
-    for (int i = 0; i < whisper_full_n_segments(ctx); i++) text += whisper_full_get_segment_text(ctx, i);
-    jbyteArray out = env->NewByteArray(static_cast<jsize>(text.size()));
-    env->SetByteArrayRegion(out, 0, static_cast<jsize>(text.size()), reinterpret_cast<const jbyte *>(text.data()));
-    return out;
-}
-
-extern "C" JNIEXPORT void JNICALL
-Java_app_seb3thehacker_gearslip_speech_SpeechEngine_nativeFree(JNIEnv *, jobject, jlong handle) {
-    if (handle) whisper_free(reinterpret_cast<whisper_context *>(handle));
-}

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

@@ -9,7 +9,6 @@ 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_SKIPPED_CERT_SETUP = "skipped_cert_setup"
     private const val KEY_SEEN_PERMISSIONS_SETUP = "seen_permissions_setup"
     private const val KEY_GEARSLIP_ENABLED = "gearslip_enabled"
@@ -32,14 +31,6 @@ 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)
-
-    fun setSeenCompatWarning(context: Context) {
-        prefs(context).edit().putBoolean(KEY_SEEN_COMPAT_WARNING, true).apply()
-    }
-
     /** Whether the certificate setup screen has been deliberately skipped. */
     fun hasSkippedCertSetup(context: Context): Boolean =
         prefs(context).getBoolean(KEY_SKIPPED_CERT_SETUP, false)

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

@@ -4,12 +4,56 @@ 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.
+ *
+ * After 0.3.40, the version code is the one the build works out from the tag (see gitVersion in
+ * build.gradle.kts): ((major*100 + minor)*100 + patch)*10 + stage, so 0.4.0-beta is 4002. Older
+ * entries keep the hand-set codes they shipped with, which are all lower.
  */
 object Changelog {
 
     class Release(val versionCode: Int, val versionName: String, val changes: List<String>)
 
     val releases = listOf(
+        Release(
+            15, "0.3.40-alpha",
+            listOf(
+                "A liked song lights up the whole like button, as shuffle and repeat do.",
+                "Music no longer carries on from the phone after you turn the car off.",
+                "Cars that hold back their screen are asked for it again in a way older cars understand.",
+            ),
+        ),
+        Release(
+            14, "0.3.39-alpha",
+            listOf(
+                "Turns from Google Maps or Waze on the phone show in the nav bar and on the car's cluster.",
+                "Alerts from car apps show here, such as Waze asking whether a hazard is still there.",
+                "Hide apps you don't use in the car from the Apps card on the phone.",
+                "Make text in car apps bigger with Car display density, under Screen.",
+                "Music playing through Gearslip comes back after a call.",
+                "Maps keep your position while the phone is locked.",
+                "Wireless keeps trying until the car answers.",
+            ),
+        ),
+        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(

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

@@ -0,0 +1,226 @@
+package app.seb3thehacker.gearslip
+
+import android.content.Context
+import android.os.Handler
+import android.os.Looper
+import app.seb3thehacker.gearslip.car.ClusterScreen
+import kotlinx.coroutines.flow.MutableStateFlow
+
+/**
+ * Gearslip's picture on the car's instrument-cluster screen: a second video sink, for a car that
+ * offers one, showing the turn card ([ClusterScreen]). The same exchange as the main screen's,
+ * on its own channel, with its own encoder and its own private display:
+ *
+ *   -> CHANNEL_OPEN_REQUEST   <- CHANNEL_OPEN_RESPONSE
+ *   -> Setup { H.264 }        <- Config { status, max_unacked, configuration_indices }
+ *   -> VideoFocusRequest      <- VideoFocusNotification { projected }
+ *   -> Start, CodecConfig, Data...   <- Ack
+ *
+ * No touch: a cluster has none. Experimental, behind [car.CarSettings.clusterVideoEnabled].
+ *
+ * Gearslip holds the cluster only while there's a route, as the card has nothing else to show.
+ * Otherwise the car keeps its own picture there: an Audi's virtual cockpit went black instead of
+ * showing its map (issue #56). [watchRoute] asks for the screen when a route starts and hands it
+ * back once there has been none for [NO_ROUTE_MS].
+ */
+internal class ClusterVideo(
+    private val context: Context,
+    private val service: ServiceDiscovery.VideoService,
+    private val send: (messageId: Int, body: ByteArray) -> Unit,
+) {
+    private val log = GearslipLog.tagged("CLUSTER")
+    private val main = Handler(Looper.getMainLooper())
+
+    val channelId get() = service.serviceId
+
+    private var configIndex = 0
+    @Volatile private var started = false
+    /** Configured and ready for focus requests. */
+    @Volatile private var ready = false
+    /** The car shows Gearslip's picture now; frames aren't sent while it shows its own. */
+    @Volatile private var projected = false
+    /** Gearslip has asked for the screen and not handed it back since. */
+    private var wanted = false
+    private var noRouteSince = 0L
+    @Volatile private var running = true
+    @Volatile private var source: VideoSource? = null
+    private var projector: ScreenProjector? = null
+
+    private val ackLock = Object()
+    @Volatile private var inFlight = 0
+    @Volatile private var maxUnacked = 1
+    @Volatile private var lastAckAt = 0L
+    private var frames = 0
+    /** The part of the picture the car's own gauges and bars leave clear, as the car last said. */
+    private val clearArea = MutableStateFlow<Insets?>(null)
+
+    fun onMessage(messageId: Int, body: ByteArray) {
+        when (messageId) {
+            GearslipRunner.MSG_CHANNEL_OPEN_RESPONSE -> {
+                val status = Protobuf.readInt32Field(body, 1) ?: 0
+                log.i("<- ChannelOpenResponse: status=$status")
+                if (status != 0) return
+                send(GearslipRunner.MSG_MEDIA_SETUP, Protobuf.varintField(1, GearslipRunner.CODEC_H264_BP.toLong()))
+                log.i("-> Setup(codec=VIDEO_H264_BP)")
+            }
+
+            GearslipRunner.MSG_MEDIA_CONFIG -> {
+                val fields = Wire.fields(body)
+                Wire.varint(fields, 2)?.toInt()?.let { maxUnacked = maxOf(1, it) }
+                val offered = fields.filter { it.number == 3 && it.wireType == 0 }.map { it.varint.toInt() }
+                // The cluster gets the smallest picture it offers: a turn card needs no more.
+                configIndex = offered.minByOrNull { service.configs.getOrNull(it)?.pixelCount() ?: Int.MAX_VALUE } ?: 0
+                log.i("<- Config status=${Wire.varint(fields, 1)} max_unacked=$maxUnacked offered=$offered - using $configIndex")
+                ready = true
+                main.post(watchRoute)
+            }
+
+            GearslipRunner.MSG_VIDEO_FOCUS_NOTIFICATION -> {
+                val mode = Wire.varint(Wire.fields(body), 1)?.toInt() ?: GearslipRunner.VIDEO_FOCUS_PROJECTED
+                log.i("<- VideoFocusNotification: mode=$mode")
+                val now = mode == GearslipRunner.VIDEO_FOCUS_PROJECTED || mode == GearslipRunner.VIDEO_FOCUS_PROJECTED_NO_INPUT
+                val back = now && !projected
+                projected = now
+                if (now && !started) startStream()
+                // Back from the car's own picture: a fresh key frame, so it doesn't start on a partial one.
+                else if (back) source?.requestSyncFrame()
+            }
+
+            GearslipRunner.MSG_MEDIA_ACK -> {
+                val acked = Wire.varint(Wire.fields(body), 2)?.toInt() ?: 1
+                synchronized(ackLock) {
+                    inFlight = maxOf(0, inFlight - maxOf(1, acked))
+                    lastAckAt = System.currentTimeMillis()
+                    ackLock.notifyAll()
+                }
+            }
+
+            // UpdateUiConfigRequest { AdditionalVideoConfig { display_insets = 1 } }: an Audi's
+            // virtual cockpit sends one as the picture starts, and draws its dials over the frame.
+            GearslipRunner.MSG_VIDEO_UI_CONFIG -> {
+                log.i("<- UpdateUiConfigRequest (${body.size} bytes)\n${Protobuf.describe(body)}")
+                clearArea.value = insetsFrom(body)
+            }
+
+            else -> log.i("<- unhandled message id=$messageId (${body.size} bytes)")
+        }
+    }
+
+    /** Once a second: the cluster follows whether there's a route. */
+    private val watchRoute = object : Runnable {
+        override fun run() {
+            if (!running || !ready) return
+            val route = app.seb3thehacker.gearslip.car.NavTurn.current() != null
+            val now = System.currentTimeMillis()
+            if (route) noRouteSince = 0L else if (noRouteSince == 0L) noRouteSince = now
+            when {
+                route && !wanted -> requestFocus(GearslipRunner.VIDEO_FOCUS_PROJECTED, "a route started")
+                !route && wanted && now - noRouteSince >= NO_ROUTE_MS -> requestFocus(GearslipRunner.VIDEO_FOCUS_NATIVE, "no route")
+            }
+            main.postDelayed(this, WATCH_MS)
+        }
+    }
+
+    private fun requestFocus(mode: Int, why: String) {
+        wanted = mode == GearslipRunner.VIDEO_FOCUS_PROJECTED
+        // VideoFocusRequestNotification { disp_channel_id = 1; mode = 2; reason = 3 }, as the main
+        // screen asks for its own picture back.
+        val reason = if (wanted) 1L else GearslipRunner.VIDEO_FOCUS_REASON_LAUNCH_NATIVE.toLong()
+        val body = Protobuf.varintField(1, channelId.toLong()) + Protobuf.varintField(2, mode.toLong()) + Protobuf.varintField(3, reason)
+        runCatching { send(GearslipRunner.MSG_VIDEO_FOCUS_REQUEST, body) }
+        log.i("-> VideoFocusRequest(mode=${if (wanted) "PROJECTED" else "NATIVE"}): $why")
+    }
+
+    private fun startStream() {
+        val config = service.configs.getOrNull(configIndex) ?: service.configs.firstOrNull() ?: return
+        val (width, height) = config.pixelSize() ?: run {
+            log.w("unsupported cluster resolution ${config.resolutionName}")
+            return
+        }
+        started = true
+        send(
+            GearslipRunner.MSG_MEDIA_START,
+            Protobuf.varintField(1, GearslipRunner.SESSION_ID.toLong()) + Protobuf.varintField(2, configIndex.toLong()),
+        )
+        log.i("-> Start(config=$configIndex -> $config)")
+        lastAckAt = System.currentTimeMillis()
+        val video = VideoSource(
+            width = width,
+            height = height,
+            frameRate = FRAME_RATE,
+            mode = VideoSource.Mode.SURFACE,
+            wireless = true, // a small share of the link: the main screen comes first
+            onCodecConfig = { csd ->
+                send(GearslipRunner.MSG_MEDIA_CODEC_CONFIG, csd)
+                log.i("-> CodecConfig (${csd.size} bytes)")
+            },
+            onFrame = { data, pts, _ -> sendFrame(data, pts) },
+        )
+        source = video
+        runCatching { video.start() }.onFailure {
+            log.e("cluster encoder failed to start", it)
+            return
+        }
+        val surface = video.inputSurface ?: return
+        val density = config.density.takeIf { it > 0 } ?: 160
+        main.post {
+            if (!running) return@post
+            projector = ScreenProjector(context).also {
+                it.start(surface, width, height, density, name = "gearslip-cluster") {
+                    // The margins the car crops off are kept clear, as on the main screen.
+                    ClusterScreen(config.widthMargin, config.heightMargin, density, clearArea)
+                }
+            }
+        }
+    }
+
+    /** As on the main screen: wait for the car's acks rather than drop a frame. */
+    private fun sendFrame(data: ByteArray, presentationTimeUs: Long) {
+        synchronized(ackLock) {
+            while (running && inFlight >= maxUnacked) {
+                val since = System.currentTimeMillis() - lastAckAt
+                if (since > GearslipRunner.ACK_STALL_MS) {
+                    inFlight = 0
+                    lastAckAt = System.currentTimeMillis()
+                    break
+                }
+                ackLock.wait(GearslipRunner.ACK_STALL_MS - since + 1)
+            }
+        }
+        if (!running || !projected) return
+        val timestamp = ByteArray(8)
+        for (i in 0 until 8) timestamp[i] = ((presentationTimeUs shr ((7 - i) * 8)) and 0xFF).toByte()
+        synchronized(ackLock) { inFlight++ }
+        runCatching { send(GearslipRunner.MSG_MEDIA_DATA, timestamp + data) }.onFailure { running = false }
+        if (++frames <= 2) log.i("-> Data frame #$frames (${data.size} bytes)")
+    }
+
+    /** VideoInsets { top = 1; bottom = 2; left = 3; right = 4 }, or null when the car sent none. */
+    private fun insetsFrom(body: ByteArray): Insets? {
+        val config = Wire.bytes(Wire.fields(body), 1) ?: return null
+        val insets = Wire.fields(Wire.bytes(Wire.fields(config), 1) ?: return null)
+        fun side(n: Int) = Wire.varint(insets, n)?.toInt() ?: 0
+        return Insets(top = side(1), bottom = side(2), left = side(3), right = side(4))
+            .also { log.i("the car keeps clear: $it") }
+    }
+
+    fun stop() {
+        running = false
+        main.removeCallbacks(watchRoute)
+        synchronized(ackLock) { ackLock.notifyAll() }
+        main.post {
+            projector?.stop()
+            projector = null
+        }
+        source?.stop()
+        source = null
+    }
+
+    private companion object {
+        // A turn card changes a few times a minute; the encoder repeats the last frame between.
+        const val FRAME_RATE = 15
+        const val WATCH_MS = 1_000L
+        /** A gap in the turns this long is the route over, not a reroute or a moment between steps. */
+        const val NO_ROUTE_MS = 10_000L
+    }
+}

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

@@ -0,0 +1,190 @@
+package app.seb3thehacker.gearslip
+
+import android.graphics.SurfaceTexture
+import android.opengl.EGL14
+import android.opengl.EGLConfig
+import android.opengl.EGLContext
+import android.opengl.EGLDisplay
+import android.opengl.EGLExt
+import android.opengl.EGLSurface
+import android.opengl.GLES11Ext
+import android.opengl.GLES20
+import android.os.Handler
+import android.os.HandlerThread
+import android.view.Surface
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+
+/**
+ * Stretches a [width] x [height] picture over the whole of an [outWidth] x [outHeight] encoder
+ * frame.
+ *
+ * For a head unit that squashes the frame onto a screen of another shape: Gearslip draws for the
+ * screen's real shape into [input], this stretches it the other way, and the car's squash brings
+ * it back. It works on the composited picture, so a map app's own surface is stretched with
+ * everything else - scaling Gearslip's UI alone would leave the map squashed.
+ */
+class FrameStretcher(
+    private val output: Surface,
+    val width: Int,
+    val height: Int,
+    private val outWidth: Int,
+    private val outHeight: Int,
+) {
+
+    private val thread = HandlerThread("gearslip-stretch").apply { start() }
+    private val handler = Handler(thread.looper)
+
+    private var display: EGLDisplay = EGL14.EGL_NO_DISPLAY
+    private var context: EGLContext = EGL14.EGL_NO_CONTEXT
+    private var eglSurface: EGLSurface = EGL14.EGL_NO_SURFACE
+    private var program = 0
+    private var texture: SurfaceTexture? = null
+    private val transform = FloatArray(16)
+
+    /** Where to draw. Valid once [start] returns true. */
+    lateinit var input: Surface
+        private set
+
+    /** Sets up on its own thread and waits for it; false if the GPU wouldn't play along. */
+    fun start(): Boolean {
+        val done = CountDownLatch(1)
+        var ok = false
+        handler.post {
+            ok = runCatching { setUp() }
+                .onFailure { GearslipLog.e("stretch: could not set up", it) }
+                .isSuccess
+            done.countDown()
+        }
+        done.await(2, TimeUnit.SECONDS)
+        if (!ok) release()
+        return ok
+    }
+
+    fun release() {
+        handler.post {
+            runCatching { if (::input.isInitialized) input.release() }
+            runCatching { texture?.release() }
+            texture = null
+            if (display != EGL14.EGL_NO_DISPLAY) {
+                EGL14.eglMakeCurrent(display, EGL14.EGL_NO_SURFACE, EGL14.EGL_NO_SURFACE, EGL14.EGL_NO_CONTEXT)
+                if (eglSurface != EGL14.EGL_NO_SURFACE) EGL14.eglDestroySurface(display, eglSurface)
+                if (context != EGL14.EGL_NO_CONTEXT) EGL14.eglDestroyContext(display, context)
+                EGL14.eglTerminate(display)
+            }
+            display = EGL14.EGL_NO_DISPLAY
+            thread.quitSafely()
+        }
+    }
+
+    private fun setUp() {
+        display = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY)
+        val version = IntArray(2)
+        check(EGL14.eglInitialize(display, version, 0, version, 1)) { "eglInitialize failed" }
+        val configs = arrayOfNulls<EGLConfig>(1)
+        val count = IntArray(1)
+        val attributes = intArrayOf(
+            EGL14.EGL_RED_SIZE, 8, EGL14.EGL_GREEN_SIZE, 8, EGL14.EGL_BLUE_SIZE, 8,
+            EGL14.EGL_RENDERABLE_TYPE, EGL14.EGL_OPENGL_ES2_BIT,
+            EGL_RECORDABLE_ANDROID, 1,
+            EGL14.EGL_NONE,
+        )
+        check(EGL14.eglChooseConfig(display, attributes, 0, configs, 0, 1, count, 0) && count[0] > 0) {
+            "no EGL config"
+        }
+        context = EGL14.eglCreateContext(
+            display, configs[0], EGL14.EGL_NO_CONTEXT,
+            intArrayOf(EGL14.EGL_CONTEXT_CLIENT_VERSION, 2, EGL14.EGL_NONE), 0,
+        )
+        eglSurface = EGL14.eglCreateWindowSurface(display, configs[0], output, intArrayOf(EGL14.EGL_NONE), 0)
+        check(EGL14.eglMakeCurrent(display, eglSurface, eglSurface, context)) { "eglMakeCurrent failed" }
+
+        program = link(VERTEX, FRAGMENT)
+        val ids = IntArray(1)
+        GLES20.glGenTextures(1, ids, 0)
+        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, ids[0])
+        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR)
+        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR)
+        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE)
+        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE)
+
+        texture = SurfaceTexture(ids[0]).apply {
+            setDefaultBufferSize(width, height)
+            setOnFrameAvailableListener({ draw() }, handler)
+        }
+        input = Surface(texture)
+        GearslipLog.i("stretch: drawing ${width}x$height, stretched to fill ${outWidth}x$outHeight")
+    }
+
+    private fun draw() {
+        val tex = texture ?: return
+        runCatching {
+            tex.updateTexImage()
+            tex.getTransformMatrix(transform)
+            GLES20.glViewport(0, 0, outWidth, outHeight)
+            GLES20.glUseProgram(program)
+            val position = GLES20.glGetAttribLocation(program, "aPosition")
+            val coord = GLES20.glGetAttribLocation(program, "aCoord")
+            GLES20.glEnableVertexAttribArray(position)
+            GLES20.glVertexAttribPointer(position, 2, GLES20.GL_FLOAT, false, 0, QUAD)
+            GLES20.glEnableVertexAttribArray(coord)
+            GLES20.glVertexAttribPointer(coord, 2, GLES20.GL_FLOAT, false, 0, COORDS)
+            GLES20.glUniformMatrix4fv(GLES20.glGetUniformLocation(program, "uTransform"), 1, false, transform, 0)
+            GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4)
+            EGLExt.eglPresentationTimeANDROID(display, eglSurface, tex.timestamp)
+            EGL14.eglSwapBuffers(display, eglSurface)
+        }.onFailure { GearslipLog.e("stretch: draw failed", it) }
+    }
+
+    private fun link(vertex: String, fragment: String): Int {
+        fun compile(type: Int, source: String): Int = GLES20.glCreateShader(type).also {
+            GLES20.glShaderSource(it, source)
+            GLES20.glCompileShader(it)
+            val status = IntArray(1)
+            GLES20.glGetShaderiv(it, GLES20.GL_COMPILE_STATUS, status, 0)
+            check(status[0] != 0) { "shader: ${GLES20.glGetShaderInfoLog(it)}" }
+        }
+        return GLES20.glCreateProgram().also {
+            GLES20.glAttachShader(it, compile(GLES20.GL_VERTEX_SHADER, vertex))
+            GLES20.glAttachShader(it, compile(GLES20.GL_FRAGMENT_SHADER, fragment))
+            GLES20.glLinkProgram(it)
+            val status = IntArray(1)
+            GLES20.glGetProgramiv(it, GLES20.GL_LINK_STATUS, status, 0)
+            check(status[0] != 0) { "program: ${GLES20.glGetProgramInfoLog(it)}" }
+        }
+    }
+
+    private companion object {
+        /** EGL_RECORDABLE_ANDROID: the config must be able to feed a video encoder. */
+        const val EGL_RECORDABLE_ANDROID = 0x3142
+
+        val QUAD = floats(-1f, -1f, 1f, -1f, -1f, 1f, 1f, 1f)
+        val COORDS = floats(0f, 0f, 1f, 0f, 0f, 1f, 1f, 1f)
+
+        fun floats(vararg values: Float) = ByteBuffer.allocateDirect(values.size * 4)
+            .order(ByteOrder.nativeOrder()).asFloatBuffer().apply { put(values); position(0) }
+
+        const val VERTEX = """
+            attribute vec4 aPosition;
+            attribute vec4 aCoord;
+            uniform mat4 uTransform;
+            varying vec2 vCoord;
+            void main() {
+                gl_Position = aPosition;
+                vCoord = (uTransform * aCoord).xy;
+            }
+        """
+
+        const val FRAGMENT = """
+            #extension GL_OES_EGL_image_external : require
+            precision mediump float;
+            varying vec2 vCoord;
+            uniform samplerExternalOES sTexture;
+            void main() {
+                gl_FragColor = texture2D(sTexture, vCoord);
+            }
+        """
+    }
+}

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

@@ -1,20 +1,10 @@
 package app.seb3thehacker.gearslip
 
 import java.io.ByteArrayOutputStream
+import java.io.IOException
+import java.io.OutputStream
 
-/**
- * Android Auto frame layout, transcribed from aasdk.
- *
- * FrameHeader::getData (src/Messenger/FrameHeader.cpp:47-55),
- * FrameSize::getData (src/Messenger/FrameSize.cpp:49-62) and
- * MessageOutStream::compoundFrame (src/Messenger/MessageOutStream.cpp:100-120):
- *
- *   byte 0     channel id
- *   byte 1     frameType | encryption | messageType
- *   bytes 2-3  uint16 BE  payload length of THIS frame
- *   bytes 4-7  uint32 BE  total message length - present ONLY when frameType == FIRST
- *   payload    uint16 BE message id, then the body
- */
+/** Android Auto framing with plaintext fragmentation before per-frame encryption. */
 object Frames {
 
     const val CHANNEL_CONTROL = 0
@@ -36,8 +26,11 @@ object Frames {
     const val MESSAGE_SPECIFIC = 0
     const val MESSAGE_CONTROL = 1 shl 2
 
-    /** aasdk splits at this size (MessageOutStream.hpp:62). Nothing the spike sends is close. */
-    const val MAX_FRAME_PAYLOAD = 0x4000
+    // Android Auto's default fragment budget includes the framing header. TLS adds overhead.
+    private const val FRAGMENT_SIZE = 0x3f00
+    private const val HEADER_SIZE = 4
+    private const val FIRST_HEADER_SIZE = 8
+    const val MAX_FRAME_PAYLOAD = FRAGMENT_SIZE - HEADER_SIZE
 
     class Frame(
         val channel: Int,
@@ -45,6 +38,7 @@ object Frames {
         val encrypted: Boolean,
         val messageType: Int,
         val payload: ByteArray,
+        val totalSize: Int? = null,
     )
 
     /**
@@ -60,6 +54,11 @@ object Frames {
         frameType: Int = TYPE_BULK,
         totalSize: Int? = null,
     ): ByteArray {
+        require(channel in 0..255 && payload.size <= 0xffff)
+        require(frameType in TYPE_MIDDLE..TYPE_BULK)
+        require(messageType == MESSAGE_SPECIFIC || messageType == MESSAGE_CONTROL)
+        require((frameType == TYPE_FIRST) == (totalSize != null))
+        require(totalSize == null || totalSize in 2..MAX_MESSAGE_SIZE)
         val flags = frameType or messageType or (if (encrypted) ENCRYPTED else 0)
         val header = byteArrayOf(
             channel.toByte(),
@@ -67,7 +66,7 @@ object Frames {
             ((payload.size shr 8) and 0xFF).toByte(),
             (payload.size and 0xFF).toByte(),
         )
-        if (frameType != TYPE_FIRST || totalSize == null) return header + payload
+        if (totalSize == null) return header + payload
         val extended = byteArrayOf(
             ((totalSize shr 24) and 0xFF).toByte(),
             ((totalSize shr 16) and 0xFF).toByte(),
@@ -77,6 +76,43 @@ object Frames {
         return header + extended + payload
     }
 
+    /** Splits plaintext before encryption; FIRST carries the complete plaintext length. */
+    fun writeMessage(
+        output: OutputStream,
+        channel: Int,
+        encrypted: Boolean,
+        messageType: Int,
+        message: ByteArray,
+        encrypt: (ByteArray) -> ByteArray,
+    ): Int {
+        require(message.size in 2..MAX_MESSAGE_SIZE)
+        val fragmented = message.size > FRAGMENT_SIZE - HEADER_SIZE
+        require(messageType != MESSAGE_CONTROL || !fragmented) { "Channel control messages cannot be fragmented" }
+        var offset = 0
+        var frames = 0
+        while (offset < message.size) {
+            val first = fragmented && offset == 0
+            val headerSize = if (first) FIRST_HEADER_SIZE else HEADER_SIZE
+            val end = minOf(offset + FRAGMENT_SIZE - headerSize, message.size)
+            val type = when {
+                !fragmented -> TYPE_BULK
+                first -> TYPE_FIRST
+                end == message.size -> TYPE_LAST
+                else -> TYPE_MIDDLE
+            }
+            val chunk = message.copyOfRange(offset, end)
+            output.write(build(channel, encrypted, if (encrypted) encrypt(chunk) else chunk,
+                messageType, type, if (type == TYPE_FIRST) message.size else null))
+            offset = end
+            frames++
+        }
+        return frames
+    }
+
+    // Local resource limits, not protocol constants. No supported media packet needs more.
+    private const val MAX_MESSAGE_SIZE = 16 * 1024 * 1024
+    private const val MAX_BUFFERED_SIZE = 32 * 1024 * 1024
+
     /**
      * Pulls whole frames out of an accumulating buffer.
      *
@@ -87,6 +123,8 @@ object Frames {
         private var pending = ByteArray(0)
 
         fun append(data: ByteArray, length: Int) {
+            require(length in 0..data.size)
+            if (length > MAX_BUFFERED_SIZE - pending.size) throw IOException("Frame buffer limit exceeded")
             val grown = ByteArray(pending.size + length)
             System.arraycopy(pending, 0, grown, 0, pending.size)
             System.arraycopy(data, 0, grown, pending.size, length)
@@ -106,30 +144,53 @@ object Frames {
             val total = headerLength + frameSize
             if (pending.size < total) return null
 
+            val messageSize = if (frameType == TYPE_FIRST) {
+                var size = 0L
+                for (i in 4..7) size = (size shl 8) or (pending[i].toLong() and 0xff)
+                if (size !in 2..MAX_MESSAGE_SIZE.toLong()) throw IOException("Invalid fragmented message length: $size")
+                size.toInt()
+            } else null
             val payload = pending.copyOfRange(headerLength, total)
             pending = pending.copyOfRange(total, pending.size)
             return Frame(
-                channel, frameType, (flags and ENCRYPTED) != 0, flags and MESSAGE_CONTROL, payload,
+                channel, frameType, (flags and ENCRYPTED) != 0, flags and MESSAGE_CONTROL, payload, messageSize,
             )
         }
     }
 
-    /** Rejoins FIRST/MIDDLE/LAST runs. Payloads arrive already decrypted. */
+    /** Rejoins messages on independent channels, validating their plaintext length and flags. */
     class Assembler {
-        private val partial = HashMap<Int, ByteArrayOutputStream>()
+        private class Partial(val first: Frame, val data: ByteArrayOutputStream = ByteArrayOutputStream())
+        private val partial = HashMap<Int, Partial>()
+        private var buffered = 0
 
-        fun offer(frame: Frame, payload: ByteArray): ByteArray? = when (frame.frameType) {
-            TYPE_BULK -> payload
-            TYPE_FIRST -> {
-                partial[frame.channel] = ByteArrayOutputStream().apply { write(payload) }
-                null
+        fun offer(frame: Frame, payload: ByteArray): ByteArray? {
+            if (frame.frameType == TYPE_BULK) {
+                if (partial.containsKey(frame.channel)) fail("Complete message interrupted fragments")
+                return payload
             }
-            TYPE_MIDDLE -> {
-                partial[frame.channel]?.write(payload)
-                null
-            }
-            TYPE_LAST -> partial.remove(frame.channel)?.apply { write(payload) }?.toByteArray()
-            else -> null
+            val message = if (frame.frameType == TYPE_FIRST) {
+                if (frame.totalSize == null || partial.containsKey(frame.channel)) fail("Invalid first fragment")
+                Partial(frame).also { partial[frame.channel] = it }
+            } else partial[frame.channel] ?: fail("Fragment without a first frame")
+            val first = message.first
+            if (first.encrypted != frame.encrypted || first.messageType != frame.messageType) fail("Fragment flags changed")
+            val expected = first.totalSize ?: fail("Missing total size")
+            if (expected !in 2..MAX_MESSAGE_SIZE || payload.size > expected - message.data.size()) fail("Fragment exceeds message length")
+            if (payload.size > MAX_BUFFERED_SIZE - buffered) fail("Fragment buffer limit exceeded")
+            message.data.write(payload)
+            buffered += payload.size
+            if (frame.frameType != TYPE_LAST) return null
+            if (message.data.size() != expected) fail("Truncated fragmented message")
+            partial.remove(frame.channel)
+            buffered -= message.data.size()
+            return message.data.toByteArray()
+        }
+
+        private fun fail(message: String): Nothing {
+            partial.clear()
+            buffered = 0
+            throw IOException(message)
         }
     }
 }

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

@@ -8,13 +8,16 @@ 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
@@ -45,6 +48,8 @@ class GearslipActivity : ComponentActivity(), Projection {
 
 
     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
@@ -72,7 +77,13 @@ 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()
         }
@@ -85,18 +96,41 @@ 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()
             }
         }
     }
 
+    /** Android's one-time "Allow" for a car to connect by itself; see [WirelessAuto]. */
+    private var approvingCar: String? = null
+
+    /** Whether the phone showed Gearslip when the car's intent arrived; see [stepAside]. */
+    private var shownOnPhone = false
+    private var stepAsideOnVideo = false
+    private val carApproval = registerForActivityResult(
+        androidx.activity.result.contract.ActivityResultContracts.StartIntentSenderForResult(),
+    ) { result ->
+        val address = approvingCar ?: return@registerForActivityResult
+        approvingCar = null
+        if (result.resultCode == RESULT_OK) app.seb3thehacker.gearslip.wireless.WirelessAuto.approved(this, address)
+        else app.seb3thehacker.gearslip.wireless.WirelessAuto.declined(this, address)
+    }
+
     /** 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")
@@ -110,12 +144,25 @@ class GearslipActivity : ComponentActivity(), Projection {
         // 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) }
+        }
+        app.seb3thehacker.gearslip.wireless.WirelessLink.sessionWaiting = { runner?.waitingForVersion == true }
+        app.seb3thehacker.gearslip.wireless.WirelessAuto.showApproval = { chooser, address ->
+            runOnUiThread {
+                approvingCar = address
+                carApproval.launch(androidx.activity.result.IntentSenderRequest.Builder(chooser).build())
+            }
+        }
         CarSettings.init(this)
+        // Before any car connects: CarServices only starts once the car shows Gearslip's screen,
+        // and a car that waits to know the phone before it shows it would never hear (issue #43).
+        app.seb3thehacker.gearslip.car.CarBluetooth.init(this)
+        app.seb3thehacker.gearslip.browser.BrowserSettings.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.
@@ -127,7 +174,33 @@ class GearslipActivity : ComponentActivity(), Projection {
 
         setContent {
             GearslipTheme {
-                GearslipApp(onDisconnect = ::closeAccessory, onRequestCallScreening = ::requestCallScreeningRole)
+                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 },
+                    )
+                }
             }
         }
 
@@ -152,6 +225,21 @@ class GearslipActivity : ComponentActivity(), Projection {
         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 onResume() {
+        super.onResume()
+        shownOnPhone = true
+    }
+
+    override fun onStop() {
+        super.onStop()
+        shownOnPhone = false
     }
 
     override fun onNewIntent(intent: Intent) {
@@ -161,6 +249,9 @@ class GearslipActivity : ComponentActivity(), Projection {
 
     override fun onDestroy() {
         super.onDestroy()
+        app.seb3thehacker.gearslip.wireless.WirelessLink.onConnected = null
+        app.seb3thehacker.gearslip.wireless.WirelessLink.sessionWaiting = null
+        app.seb3thehacker.gearslip.wireless.WirelessAuto.showApproval = null
         runCatching { unregisterReceiver(detachReceiver) }
         PhoneMirror.onStartRequested = null
         PhoneMirror.onTokenReady = null
@@ -225,7 +316,8 @@ class GearslipActivity : ComponentActivity(), Projection {
         val target = surface ?: return
         if (screenProjector != null) return
         val projector = ScreenProjector(this).also { screenProjector = it }
-        projector.start(target, frameWidth, frameHeight, frameDensity) { CarUi() }
+        // The frame's density, not frameDensity: that stays the car's own, for the phone mirror.
+        projector.start(target, frameWidth, frameHeight, CarEnvironment.frame.value.densityDpi) { CarUi() }
     }
 
     /**
@@ -249,6 +341,13 @@ class GearslipActivity : ComponentActivity(), Projection {
     }
 
     private fun handleIntent(intent: Intent?) {
+        // Debug builds only: opens the audio choice for a look, without turning down a real prompt.
+        if (BuildConfig.DEBUG && intent?.getBooleanExtra("show_audio_choice", false) == true) offerBluetooth.value = true
+        if (intent?.action == app.seb3thehacker.gearslip.wireless.WirelessAuto.ACTION_CAR_NEARBY) {
+            stepAsideOnVideo = !shownOnPhone
+            connectToNearbyCar(intent.getStringExtra(app.seb3thehacker.gearslip.wireless.WirelessAuto.EXTRA_ADDRESS))
+            return
+        }
         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.
@@ -263,9 +362,43 @@ class GearslipActivity : ComponentActivity(), Projection {
             return
         }
         GearslipLog.i("accessory attached by the system - permission is implicit on this path")
+        stepAsideOnVideo = !shownOnPhone
         start(accessory)
     }
 
+    /** A known car came up over Bluetooth: connect wirelessly, unless USB or another try is already on it. */
+    private fun connectToNearbyCar(address: String?) {
+        if (address == null) return
+        if (!AppSettings.gearslipEnabled(this)) {
+            GearslipLog.i("auto-connect: Gearslip is switched off - not connecting")
+            return
+        }
+        if (descriptor != null) {
+            GearslipLog.i("auto-connect: the car is on USB already - staying on USB")
+            return
+        }
+        // Only a session that's still running counts. One the car ended (a ByeBye, a dropped
+        // network) leaves its runner behind, since only Gearslip ending a session clears it, and
+        // that used to make every later auto-connect quietly do nothing.
+        if (worker?.isAlive == true || app.seb3thehacker.gearslip.wireless.WirelessLink.busy) {
+            GearslipLog.i("auto-connect: a session is already running")
+            return
+        }
+        if (runner != null) closeAccessory(stopWireless = false)
+        if (checkSelfPermission(android.Manifest.permission.BLUETOOTH_CONNECT) != android.content.pm.PackageManager.PERMISSION_GRANTED) {
+            GearslipLog.w("auto-connect: needs the Nearby devices permission")
+            return
+        }
+        val adapter = getSystemService(android.bluetooth.BluetoothManager::class.java)?.adapter
+        val device = adapter?.let { runCatching { it.getRemoteDevice(address) }.getOrNull() }
+        if (device == null) {
+            GearslipLog.w("auto-connect: Bluetooth couldn't hand over the car")
+            return
+        }
+        GearslipLog.i("auto-connect: connecting")
+        app.seb3thehacker.gearslip.wireless.WirelessLink.start(this, device)
+    }
+
     private fun start(accessory: UsbAccessory) {
         // 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
@@ -291,9 +424,49 @@ class GearslipActivity : ComponentActivity(), Projection {
             identityProvider = { CertProvider.load(this) },
             projection = this,
             vehicleProfileFor = { info -> VehicleProfiles.find(VehicleProfiles.load(this), info) },
+            phoneIcons = { PhoneIcons.pngs(this) },
         )
         this.runner = runner
         worker = Thread { runner.run() }.apply { name = "gearslip"; start() }
+        holdLocation()
+    }
+
+    /** 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,
+            phoneIcons = { PhoneIcons.pngs(this) },
+        )
+        this.runner = runner
+        worker = Thread { runner.run() }.apply { name = "gearslip"; start() }
+        holdLocation()
+    }
+
+    /** Whether this session holds [app.seb3thehacker.gearslip.host.LocationKeepAlive]. */
+    private var holdingLocation = false
+
+    /**
+     * Android lets a foreground service started from the background use location only in the few
+     * seconds after one of the app's screens opens. The car just opened this one, so take the
+     * location service now: a map bound later, with the phone already locked, got no position.
+     */
+    private fun holdLocation() {
+        if (holdingLocation) return
+        holdingLocation = true
+        app.seb3thehacker.gearslip.host.LocationKeepAlive.acquire(this) {}
     }
 
     private fun describe(accessory: UsbAccessory) {
@@ -301,16 +474,39 @@ class GearslipActivity : ComponentActivity(), Projection {
         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
+        if (holdingLocation) {
+            holdingLocation = false
+            app.seb3thehacker.gearslip.host.LocationKeepAlive.release(this)
+        }
     }
 
     // --- Projection ---------------------------------------------------------------------
 
+    /**
+     * The car opens Gearslip on the phone, since Android hands a USB car only to an activity and
+     * auto-connect has to start one too. Once the car's screen is up, go back to whatever the
+     * phone showed, as Home would; the session carries on as it does with the phone locked. A
+     * question for the driver keeps Gearslip in front, and so does the phone already showing it.
+     */
+    private fun stepAside() {
+        stepAsideOnVideo = false
+        if (offerBluetooth.value || micBlockedNotice.value || approvingCar != null) return
+        GearslipLog.i("the car's screen is up - moving Gearslip off the phone's screen")
+        moveTaskToBack(true)
+    }
+
     override fun onSurfaceReady(surface: Surface, width: Int, height: Int, densityDpi: Int) {
         runOnUiThread {
             this.surface = surface
@@ -320,6 +516,7 @@ class GearslipActivity : ComponentActivity(), Projection {
             CarEnvironment.setDisplay(width, height, densityDpi)
             CarEnvironment.start(this)
             showCarUi()
+            if (stepAsideOnVideo) stepAside()
             app.seb3thehacker.gearslip.car.CarKeys.focusSink = { code, down ->
                 runOnUiThread { screenProjector?.dispatchKey(code, down) }
             }
@@ -336,7 +533,13 @@ class GearslipActivity : ComponentActivity(), Projection {
         }
     }
 
+    override fun onStill() {
+        screenProjector?.redraw()
+    }
+
     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

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

@@ -47,11 +47,109 @@ object GearslipLog {
     val version: StateFlow<Int> = liveVersion
 
     fun init(context: Context) {
+        // The phone app and the launcher both start here; one file per process.
+        if (file != null) return
         val dir = context.getExternalFilesDir(null) ?: return
         val name = SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US).format(Date())
         file = File(dir, "gearslip-$name.log")
         i("log file: ${file?.absolutePath}")
         SessionReport.init(context)
+        // One file per launch adds up; the newest are the ones anyone asks for.
+        io.execute { logFiles(dir).drop(KEEP_FILES).forEach { it.delete() } }
+        lastExit(context, dir)
+    }
+
+    private const val KEEP_FILES = 30
+    private const val KEY_EXIT_SEEN = "log_exit_seen"
+
+    /**
+     * Why Android ended the last run, when the crash handler can't have seen it: a native crash,
+     * a freeze (ANR), or the memory killer. Written here and onto the end of that run's own log,
+     * which is the one a driver shares after a drive that went wrong.
+     */
+    private fun lastExit(context: Context, dir: File) {
+        val am = context.getSystemService(android.app.ActivityManager::class.java) ?: return
+        val seen = AppSettings.getString(context, KEY_EXIT_SEEN, "0").toLongOrNull() ?: 0L
+        val exits = runCatching { am.getHistoricalProcessExitReasons(null, 0, 5) }.getOrDefault(emptyList())
+            .filter { it.timestamp > seen }
+        exits.firstOrNull()?.let { AppSettings.putString(context, KEY_EXIT_SEEN, it.timestamp.toString()) }
+        val parse = SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US)
+        for (exit in exits.reversed()) {
+            val why = EXIT_REASONS[exit.reason] ?: continue
+            val at = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US).format(Date(exit.timestamp))
+            val detail = buildString {
+                append("$at, $why")
+                exit.description?.takeIf { it.isNotBlank() }?.let { append(" ($it)") }
+                append(", memory ${exit.pss / 1024} MB")
+                if (exit.reason == android.app.ApplicationExitInfo.REASON_ANR) {
+                    anrMainThread(exit)?.let { append("\n").append(it) }
+                }
+            }
+            w("Android ended an earlier run at $detail")
+            // The run that died: the newest log that started before it ended.
+            val run = logFiles(dir).filter { it != file }.firstOrNull { f ->
+                val started = runCatching { parse.parse(f.name.removePrefix("gearslip-").removeSuffix(".log")) }.getOrNull()
+                started != null && started.time <= exit.timestamp
+            } ?: continue
+            io.execute { runCatching { run.appendText("--- $EXIT_MARK $detail\n") } }
+        }
+    }
+
+    /** The main thread's stack from an ANR trace: what Gearslip was stuck doing. */
+    private fun anrMainThread(exit: android.app.ApplicationExitInfo): String? = runCatching {
+        exit.traceInputStream?.bufferedReader()?.useLines { lines ->
+            lines.dropWhile { !it.startsWith("\"main\"") }.take(ANR_LINES).joinToString("\n")
+        }?.takeIf { it.isNotBlank() }
+    }.getOrNull()
+
+    private const val ANR_LINES = 25
+    private const val EXIT_MARK = "Android ended this run:"
+
+    /** Exit reasons worth a line; leaving, updating and Java crashes (already logged) aren't. */
+    private val EXIT_REASONS = mapOf(
+        android.app.ApplicationExitInfo.REASON_CRASH_NATIVE to "a native crash",
+        android.app.ApplicationExitInfo.REASON_ANR to "the app stopped responding (ANR)",
+        android.app.ApplicationExitInfo.REASON_LOW_MEMORY to "the phone ran low on memory",
+        android.app.ApplicationExitInfo.REASON_EXCESSIVE_RESOURCE_USAGE to "it used too much of the phone's resources",
+        android.app.ApplicationExitInfo.REASON_INITIALIZATION_FAILURE to "it failed to start",
+        android.app.ApplicationExitInfo.REASON_SIGNALED to "the system killed it",
+        android.app.ApplicationExitInfo.REASON_DEPENDENCY_DIED to "something it depends on died",
+    )
+
+    private fun logFiles(dir: File): List<File> =
+        dir.listFiles { f -> f.isFile && f.name.startsWith("gearslip-") && f.name.endsWith(".log") }
+            ?.sortedByDescending { it.name }.orEmpty()
+
+    /** A log from an earlier launch: when it started, and what a glance at it tells. */
+    class PastLog(val file: File, val started: Date?, val crashed: Boolean, val car: String?)
+
+    /**
+     * Earlier launches' logs, newest first. Each launch starts a fresh file, so after a crash the
+     * one that saw it is here rather than on the live screen.
+     */
+    fun pastLogs(context: Context): List<PastLog> {
+        val dir = context.getExternalFilesDir(null) ?: return emptyList()
+        val parse = SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US)
+        return logFiles(dir).filter { it != file }.map { f ->
+            val text = runCatching { f.readText() }.getOrDefault("")
+            PastLog(
+                file = f,
+                started = runCatching { parse.parse(f.name.removePrefix("gearslip-").removeSuffix(".log")) }.getOrNull(),
+                crashed = "FATAL uncaught" in text || EXIT_MARK in text,
+                car = Regex("""car="([^"]+)"""").findAll(text).lastOrNull()?.groupValues?.get(1),
+            )
+        }
+    }
+
+    /** An earlier launch's log, copied to the cache dir for sharing like [shareableFile]. */
+    fun shareableFile(context: Context, past: File): android.net.Uri {
+        val dir = File(context.cacheDir, "shared").apply { mkdirs() }
+        dir.listFiles()?.forEach { it.delete() }
+        val out = File(dir, "gearslip-log-${past.name.removePrefix("gearslip-").removeSuffix(".log")}.txt")
+        past.copyTo(out, overwrite = true)
+        return androidx.core.content.FileProvider.getUriForFile(
+            context, "${context.packageName}.logshare", out,
+        )
     }
 
     fun snapshot(): List<String> = synchronized(live) { live.toList() }
@@ -133,7 +231,11 @@ object GearslipLog {
      * Records an uncaught exception in the log file before the process dies, then lets the
      * system's own handler run. Without it the file ends mid-sentence and the reason is lost.
      */
+    @Volatile private var crashHandlerInstalled = false
+
     fun installCrashHandler() {
+        if (crashHandlerInstalled) return
+        crashHandlerInstalled = true
         val previous = Thread.getDefaultUncaughtExceptionHandler()
         Thread.setDefaultUncaughtExceptionHandler { thread, throwable ->
             runCatching {

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

@@ -0,0 +1,152 @@
+package app.seb3thehacker.gearslip
+
+import android.content.Intent
+import android.content.res.Configuration
+import android.os.Bundle
+import android.view.KeyEvent
+import android.view.WindowManager
+import androidx.activity.ComponentActivity
+import androidx.activity.OnBackPressedCallback
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.core.view.WindowCompat
+import androidx.core.view.WindowInsetsCompat
+import androidx.core.view.WindowInsetsControllerCompat
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import app.seb3thehacker.gearslip.car.CarEnvironment
+import app.seb3thehacker.gearslip.car.CarKeys
+import app.seb3thehacker.gearslip.car.CarSettings
+import app.seb3thehacker.gearslip.car.CarUi
+import app.seb3thehacker.gearslip.car.LauncherMode
+import app.seb3thehacker.gearslip.car.Prefetch
+import app.seb3thehacker.gearslip.ui.CarFrame
+import app.seb3thehacker.gearslip.ui.GearslipTheme
+import app.seb3thehacker.gearslip.ui.rememberCarProjector
+
+/**
+ * The home screen in launcher mode (see [LauncherMode]): the car UI, filling this device's own
+ * screen. It runs for as long as the activity lives, not only while it's in front, so a map
+ * keeps guiding and music keeps playing while another app is open over it.
+ */
+class LauncherActivity : ComponentActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        GearslipLog.init(this)
+        GearslipLog.installCrashHandler()
+        CarSettings.init(this)
+        CarKeys.init(this)
+        Prefetch.warm(this)
+        CarEnvironment.setPhoneTheme(resources.configuration)
+
+        // A dash screen is something to glance at: it stays on, with the system bars out of the way.
+        window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+        WindowCompat.setDecorFitsSystemWindows(window, false)
+        WindowInsetsControllerCompat(window, window.decorView).apply {
+            systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
+            hide(WindowInsetsCompat.Type.systemBars())
+        }
+        // Back moves back in the car UI. A home screen has nowhere else to go back to.
+        onBackPressedDispatcher.addCallback(this, object : OnBackPressedCallback(true) {
+            override fun handleOnBackPressed() {
+                CarKeys.onKey(KeyEvent.KEYCODE_BACK, down = true, longPress = false)
+            }
+        })
+
+        setContent {
+            GearslipTheme {
+                LauncherScreen(onOpenGearslip = { startActivity(Intent(this, GearslipActivity::class.java)) })
+            }
+        }
+    }
+
+    /** Home pressed while Gearslip is already the home screen: back to the car UI's Home. */
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        CarKeys.onKey(KeyEvent.KEYCODE_HOME, down = true, longPress = false)
+    }
+
+    override fun onConfigurationChanged(newConfig: Configuration) {
+        super.onConfigurationChanged(newConfig)
+        CarEnvironment.setPhoneTheme(newConfig)
+    }
+
+    /** A head unit's knob, D-pad and hard keys work the car UI the way a car's do. */
+    override fun dispatchKeyEvent(event: KeyEvent): Boolean {
+        if (event.keyCode != KeyEvent.KEYCODE_BACK && event.repeatCount == 0 &&
+            CarKeys.onKey(event.keyCode, event.action == KeyEvent.ACTION_DOWN, event.isLongPress)
+        ) return true
+        return super.dispatchKeyEvent(event)
+    }
+}
+
+@Composable
+private fun LauncherScreen(onOpenGearslip: () -> Unit) {
+    val status by SessionStatus.state.collectAsStateWithLifecycle()
+    // Plugged into a car, this device is the phone and the car UI belongs on the car's screen.
+    val inCar = status.phase == SessionStatus.Phase.CONNECTING || status.phase == SessionStatus.Phase.PROJECTING
+    if (inCar) {
+        InCarNotice(onOpenGearslip)
+        return
+    }
+    BoxWithConstraints(Modifier.fillMaxSize().background(MaterialTheme.colorScheme.background)) {
+        val px = with(LocalDensity.current) { maxWidth.roundToPx() / 2 * 2 to maxHeight.roundToPx() / 2 * 2 }
+        val (width, height) = px
+        if (width <= 0 || height <= 0) return@BoxWithConstraints
+        // Car-like text and buttons: 160dpi for every 480 pixels of height, as the car preview uses.
+        // This screen stands in for the car's, so hosted apps size to it and the density setting applies.
+        val density = remember(width, height) {
+            CarEnvironment.setDisplay(width, height, (160 * height / 480).coerceIn(120, 640))
+            CarEnvironment.frame.value.densityDpi
+        }
+        // Before the projector starts, so the car UI's first screen already knows what to hide.
+        DisposableEffect(Unit) {
+            LauncherMode.setActive(true)
+            onDispose { LauncherMode.setActive(false) }
+        }
+        val projector = rememberCarProjector(width, height, density, "gearslip-launcher") { CarUi() }
+        DisposableEffect(projector) {
+            CarKeys.focusSink = { code, down -> projector.dispatchKey(code, down) }
+            onDispose { CarKeys.focusSink = null }
+        }
+        CarFrame(projector, width, height, Modifier.fillMaxSize())
+    }
+}
+
+@Composable
+private fun InCarNotice(onOpenGearslip: () -> Unit) {
+    Column(
+        Modifier.fillMaxSize().background(MaterialTheme.colorScheme.background).padding(32.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.Center,
+    ) {
+        Text(
+            stringResource(R.string.launcher_in_car),
+            style = MaterialTheme.typography.titleLarge,
+            textAlign = TextAlign.Center,
+            color = MaterialTheme.colorScheme.onBackground,
+        )
+        Spacer(Modifier.height(16.dp))
+        Button(onClick = onOpenGearslip) { Text(stringResource(R.string.launcher_open_gearslip)) }
+    }
+}

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

@@ -0,0 +1,49 @@
+package app.seb3thehacker.gearslip
+
+import android.app.Activity
+import android.app.ActivityOptions
+import android.content.Context
+import android.content.Intent
+import android.os.Bundle
+import android.view.Display
+
+/**
+ * Asks for runtime permissions on the phone's own screen, for a car screen that can't show
+ * Android's dialog itself. It has no look of its own: the dialog appears, the answer is given,
+ * and it finishes.
+ */
+class PermissionActivity : Activity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        val wanted = intent.getStringArrayExtra(EXTRA_PERMISSIONS)
+            ?.filter { checkSelfPermission(it) != android.content.pm.PackageManager.PERMISSION_GRANTED }
+            .orEmpty()
+        if (wanted.isEmpty() || savedInstanceState != null) {
+            if (wanted.isEmpty()) finish()
+            return
+        }
+        requestPermissions(wanted.toTypedArray(), REQUEST)
+    }
+
+    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        GearslipLog.i("permissions: ${permissions.zip(grantResults.toList()).joinToString { (p, r) -> "${p.substringAfterLast('.')}=${r == 0}" }}")
+        finish()
+    }
+
+    companion object {
+        private const val EXTRA_PERMISSIONS = "permissions"
+        private const val REQUEST = 1
+
+        /** Shows the permission dialog on the phone, whichever screen [context] belongs to. */
+        fun ask(context: Context, permissions: Array<String>) {
+            val intent = Intent(context, PermissionActivity::class.java)
+                .putExtra(EXTRA_PERMISSIONS, permissions)
+                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            val options = ActivityOptions.makeBasic().setLaunchDisplayId(Display.DEFAULT_DISPLAY)
+            runCatching { context.startActivity(intent, options.toBundle()) }
+                .onFailure { GearslipLog.w("permissions: could not ask on the phone: ${it.message}") }
+        }
+    }
+}

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

@@ -0,0 +1,34 @@
+package app.seb3thehacker.gearslip
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.Canvas
+import java.io.ByteArrayOutputStream
+
+/**
+ * Gearslip's own icon as the PNGs a phone hands the car in its ServiceDiscoveryRequest, at the
+ * 32, 64 and 128 px a real phone sends. Cars draw the phone's tile on their home screen from
+ * them, and older head units may wait for them before answering at all.
+ */
+object PhoneIcons {
+
+    private val SIZES = intArrayOf(32, 64, 128)
+
+    @Volatile private var cached: List<ByteArray>? = null
+
+    /** The three PNGs, smallest first; empty if the icon can't be drawn. */
+    fun pngs(context: Context): List<ByteArray> = cached ?: runCatching {
+        val icon = context.packageManager.getApplicationIcon(context.applicationInfo).mutate()
+        SIZES.map { size ->
+            val bitmap = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888)
+            icon.setBounds(0, 0, size, size)
+            icon.draw(Canvas(bitmap))
+            val png = ByteArrayOutputStream()
+            bitmap.compress(Bitmap.CompressFormat.PNG, 100, png)
+            bitmap.recycle()
+            png.toByteArray()
+        }
+    }.onFailure { GearslipLog.w("phone icons: couldn't draw them (${it.message})") }
+        .getOrDefault(emptyList())
+        .also { if (it.isNotEmpty()) cached = it }
+}

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

@@ -1,5 +1,6 @@
 package app.seb3thehacker.gearslip
 
+import java.io.ByteArrayOutputStream
 import java.net.Socket
 import java.nio.ByteBuffer
 import java.security.KeyStore
@@ -11,23 +12,10 @@ import javax.net.ssl.SSLEngine
 import javax.net.ssl.SSLEngineResult
 import javax.net.ssl.SSLEngineResult.HandshakeStatus
 import javax.net.ssl.SSLPeerUnverifiedException
+import javax.net.ssl.SSLException
 import javax.net.ssl.X509ExtendedTrustManager
 
-/**
- * The phone end of the Android Auto TLS session.
- *
- * Two things here are the opposite of what aasdk does, because aasdk implements the head
- * unit and the head unit is the TLS *client*: it calls TLS_client_method() and
- * SSL_set_connect_state (src/Transport/SSLWrapper.cpp:97-140, src/Messenger/Cryptor.cpp:87),
- * and SSL_set_accept_state appears nowhere in that codebase. So the phone is the TLS
- * **server** and its certificate goes out as the server certificate - sent unconditionally
- * on every handshake, which is precisely what we are testing.
- *
- * TLS here is not layered over the socket: handshake bytes travel inside
- * MESSAGE_ENCAPSULATED_SSL control messages (id 3). That rules out SSLSocket and makes
- * SSLEngine - a buffer-to-buffer engine, the JSSE counterpart of aasdk's memory BIO pair -
- * the right tool.
- */
+/** TLS server for projection. Handshake records travel in control message 3, not a TLS socket. */
 class PhoneTls(keyStore: KeyStore, password: CharArray) {
     private val log = GearslipLog.tagged("TLS")
 
@@ -36,7 +24,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
     private var appBuffer = ByteBuffer.allocate(32 * 1024)
     private var netBuffer = ByteBuffer.allocate(32 * 1024)
 
-    var handshakeComplete: Boolean = false
+    @Volatile var handshakeComplete: Boolean = false
         private set
 
     init {
@@ -52,6 +40,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
             useClientMode = false
             // want, not need: we ask the head unit for its certificate so the run also tells
             // us what real units present, but we never make the session depend on getting one.
+            // Homemade head units may have none.
             wantClientAuth = true
             enabledProtocols = arrayOf("TLSv1.2") // aasdk pins TLS 1.2
         }
@@ -88,7 +77,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
                     if (netBuffer.hasRemaining()) {
                         outgoing += ByteArray(netBuffer.remaining()).also { netBuffer.get(it) }
                     }
-                    if (result.status == SSLEngineResult.Status.CLOSED) break@loop
+                    if (result.status == SSLEngineResult.Status.CLOSED) throw SSLException("TLS closed during handshake")
                 }
 
                 HandshakeStatus.NEED_UNWRAP -> {
@@ -100,7 +89,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
                             appBuffer = ByteBuffer.allocate(appBuffer.capacity() * 2)
                             continue@loop
                         }
-                        SSLEngineResult.Status.CLOSED -> break@loop
+                        SSLEngineResult.Status.CLOSED -> throw SSLException("TLS closed during handshake")
                         else -> Unit
                     }
                 }
@@ -124,7 +113,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
     /** Wraps a control-channel payload for an ENCRYPTED frame. */
     fun encrypt(plain: ByteArray): ByteArray {
         val source = ByteBuffer.wrap(plain)
-        val out = java.io.ByteArrayOutputStream()
+        val out = ByteArrayOutputStream()
         while (source.hasRemaining()) {
             netBuffer.clear()
             val result = engine.wrap(source, netBuffer)
@@ -132,6 +121,9 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
                 netBuffer = ByteBuffer.allocate(netBuffer.capacity() * 2)
                 continue
             }
+            if (result.status != SSLEngineResult.Status.OK || result.bytesConsumed() == 0) {
+                throw SSLException("TLS could not encrypt application data: ${result.status}")
+            }
             netBuffer.flip()
             val chunk = ByteArray(netBuffer.remaining())
             netBuffer.get(chunk)
@@ -140,14 +132,10 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
         return out.toByteArray()
     }
 
-    /**
-     * Unwraps one ENCRYPTED frame's payload. aasdk decrypts per frame
-     * (MessageOutStream::compoundFrame encrypts per frame), so each frame's payload is
-     * self-contained ciphertext.
-     */
+    /** Each encrypted projection frame contains complete TLS records. */
     fun decrypt(cipher: ByteArray): ByteArray {
         val source = ByteBuffer.wrap(cipher)
-        val out = java.io.ByteArrayOutputStream()
+        val out = ByteArrayOutputStream()
         while (source.hasRemaining()) {
             appBuffer.clear()
             val result = engine.unwrap(source, appBuffer)
@@ -157,10 +145,9 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
                     continue
                 }
                 SSLEngineResult.Status.BUFFER_UNDERFLOW -> {
-                    log.w("decrypt: record split across frames (${source.remaining()} bytes left over)")
-                    break
+                    throw SSLException("Incomplete TLS record in an encrypted frame")
                 }
-                SSLEngineResult.Status.CLOSED -> break
+                SSLEngineResult.Status.CLOSED -> throw SSLException("TLS peer closed the connection")
                 else -> Unit
             }
             appBuffer.flip()

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

@@ -8,7 +8,8 @@ object ProjectedContent {
 
     /**
      * Precedence: the URL saved in Settings, then a `url.txt` in the external files dir (the
-     * pre-Settings way, still honoured so existing setups keep working), then [DEFAULT_URL].
+     * pre-Settings way, still honoured so existing setups keep working). Blank opens the
+     * browser's own start page.
      */
     fun resolve(context: Context): String {
         val saved = AppSettings.startupUrl(context)
@@ -25,12 +26,9 @@ object ProjectedContent {
                 return url
             }
         }
-        return DEFAULT_URL
+        return ""
     }
 
-    /** What the Web app opens until a page is chosen in Settings. */
-    const val DEFAULT_URL = "https://duckduckgo.com"
-
     /** A bare "example.com" is a URL the user meant; raw HTML is passed through untouched. */
     private fun normalize(value: String): String =
         if (value.startsWith("<") || "://" in value) value else "https://$value"

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

@@ -24,6 +24,12 @@ interface Projection {
     fun onTouch(action: Int, actionIndex: Int, points: List<TouchPoint>)
 
     fun onProjectionStopped()
+
+    /**
+     * The screen has been still for a moment and the encoder has sent nothing since. Draw it once
+     * more, so the car gets a fresh frame (see [VideoSource]'s onStill).
+     */
+    fun onStill() {}
 }
 
 /** One finger on the car's screen: a stable [id] for as long as it stays down, and where it is. */

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

@@ -2,14 +2,7 @@ package app.seb3thehacker.gearslip
 
 import java.io.ByteArrayOutputStream
 
-/**
- * Just enough protobuf to run the spike, hand-rolled so there is no protoc step.
- *
- * Only three messages are ever written (AuthResponse is only read):
- *   ServiceDiscoveryRequest { optional string label_text = 4; optional string device_name = 5; }
- *   PingResponse            { required int64 timestamp = 1; }
- *   AuthResponse            { required int32 status = 1; }
- */
+/** Protobuf field encoding and diagnostic rendering for the projection protocol. */
 object Protobuf {
 
     fun varint(value: Long): ByteArray {
@@ -31,6 +24,9 @@ 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)
 
@@ -38,29 +34,7 @@ object Protobuf {
     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
-            pos = afterTag
-            val number = (tag ushr 3).toInt()
-            when ((tag and 7L).toInt()) {
-                0 -> {
-                    val (value, afterValue) = readVarint(data, pos) ?: return null
-                    pos = afterValue
-                    if (number == field) return value
-                }
-                2 -> {
-                    val (len, afterLen) = readVarint(data, pos) ?: return null
-                    pos = afterLen + len.toInt()
-                }
-                5 -> pos += 4
-                1 -> pos += 8
-                else -> return null
-            }
-        }
-        return null
-    }
+    fun readInt64Field(data: ByteArray, field: Int): Long? = Wire.varint(Wire.fields(data), field)
 
     /**
      * Shallow field dump. Used on ServiceDiscoveryResponse: its make/model/year strings
@@ -68,6 +42,7 @@ object Protobuf {
      * proof that the session is live and we are decrypting correctly.
      */
     fun describe(data: ByteArray, indent: String = "  "): String {
+        if (indent.length > 32) return "$indent(nested message)\n"
         val sb = StringBuilder()
         var pos = 0
         while (pos < data.size) {
@@ -86,6 +61,7 @@ object Protobuf {
                 }
                 2 -> {
                     val (len, afterLen) = readVarint(data, pos) ?: break
+                    if (len < 0 || len > data.size - afterLen) break
                     val end = afterLen + len.toInt()
                     if (end > data.size) break
                     val body = data.copyOfRange(afterLen, end)
@@ -114,6 +90,7 @@ object Protobuf {
         var pos = start
         while (pos < data.size && shift <= 63) {
             val b = data[pos].toInt() and 0xFF
+            if (shift == 63 && b > 1) return null
             result = result or ((b and 0x7F).toLong() shl shift)
             pos++
             if (b and 0x80 == 0) return result to pos
@@ -132,45 +109,68 @@ object Wire {
         val out = mutableListOf<Field>()
         var pos = 0
         while (pos < data.size) {
-            val tag = readVarint(data, pos) ?: break
+            val tag = readVarint(data, pos) ?: return emptyList()
             pos = tag.second
             val number = (tag.first ushr 3).toInt()
+            if (tag.first ushr 3 !in 1..0x1fff_ffffL) return emptyList()
             when ((tag.first and 7L).toInt()) {
                 0 -> {
-                    val v = readVarint(data, pos) ?: break
+                    val v = readVarint(data, pos) ?: return emptyList()
                     pos = v.second
                     out += Field(number, 0, v.first, null)
                 }
-                1 -> { if (pos + 8 > data.size) break; pos += 8 }
+                1 -> { if (data.size - pos < 8) return emptyList(); pos += 8 }
                 2 -> {
-                    val len = readVarint(data, pos) ?: break
+                    val len = readVarint(data, pos) ?: return emptyList()
+                    if (len.first < 0 || len.first > data.size - len.second) return emptyList()
                     val end = len.second + len.first.toInt()
-                    if (end > data.size || end < len.second) break
+                    if (end > data.size || end < len.second) return emptyList()
                     out += Field(number, 2, 0, data.copyOfRange(len.second, end))
                     pos = end
                 }
-                5 -> { if (pos + 4 > data.size) break; pos += 4 }
-                else -> break
+                5 -> { if (data.size - pos < 4) return emptyList(); pos += 4 }
+                else -> return emptyList()
             }
         }
         return out
     }
 
     fun varint(fields: List<Field>, number: Int): Long? =
-        fields.firstOrNull { it.number == number && it.wireType == 0 }?.varint
+        fields.lastOrNull { it.number == number && it.wireType == 0 }?.varint
 
     fun bytes(fields: List<Field>, number: Int): ByteArray? =
-        fields.firstOrNull { it.number == number && it.wireType == 2 }?.bytes
+        fields.lastOrNull { it.number == number && it.wireType == 2 }?.bytes
 
     fun allBytes(fields: List<Field>, number: Int): List<ByteArray> =
         fields.filter { it.number == number && it.wireType == 2 }.mapNotNull { it.bytes }
 
+    /** Protobuf readers accept both packed and unpacked repeated numeric fields. */
+    fun repeatedInts(fields: List<Field>, number: Int): List<Int> =
+        repeatedLongs(fields, number)?.map(Long::toInt).orEmpty()
+
+    /** Null means a packed field contained an incomplete or overflowing varint. */
+    fun repeatedLongs(fields: List<Field>, number: Int): List<Long>? = buildList {
+        for (field in fields.filter { it.number == number }) {
+            if (field.wireType == 0) add(field.varint)
+            else if (field.wireType == 2) {
+                val bytes = field.bytes ?: continue
+                var position = 0
+                while (position < bytes.size) {
+                    val (value, next) = readVarint(bytes, position) ?: return null
+                    add(value)
+                    position = next
+                }
+            }
+        }
+    }
+
     private fun readVarint(data: ByteArray, start: Int): Pair<Long, Int>? {
         var result = 0L
         var shift = 0
         var pos = start
         while (pos < data.size && shift <= 63) {
             val b = data[pos].toInt() and 0xFF
+            if (shift == 63 && b > 1) return null
             result = result or ((b and 0x7F).toLong() shl shift)
             pos++
             if (b and 0x80 == 0) return result to pos

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

@@ -0,0 +1,17 @@
+package app.seb3thehacker.gearslip
+
+/**
+ * Advertises our supported 1.x version, as Android Auto does for older head units. Head units that
+ * offer a newer major version (LIVI asks for 6.1, a RAV4 and the DHU for 4.2) still accept a 1.x
+ * answer, so only a major version of 0 is refused.
+ */
+internal object ProtocolVersion {
+    data class Response(val major: Int, val minor: Int, val supported: Boolean) {
+        val bytes: ByteArray get() = byteArrayOf(
+            (major ushr 8).toByte(), major.toByte(), (minor ushr 8).toByte(), minor.toByte(),
+            if (supported) 0 else -1, if (supported) 0 else -1,
+        )
+    }
+
+    fun respond(major: Int, minor: Int): Response = Response(1, 7, major >= 1 && minor in 0..0xffff)
+}

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

@@ -1,15 +1,18 @@
 package app.seb3thehacker.gearslip
 
 import android.app.ActivityOptions
+import android.app.LocaleManager
 import android.app.Presentation
 import android.content.Context
 import android.content.Intent
+import android.content.res.Configuration
 import android.graphics.Color
 import android.hardware.display.DisplayManager
 import android.hardware.display.VirtualDisplay
 import android.os.SystemClock
 import android.view.MotionEvent
 import android.view.Surface
+import android.view.ContextThemeWrapper
 import android.view.View
 import android.view.ViewGroup
 import androidx.compose.runtime.Composable
@@ -51,7 +54,7 @@ class ScreenProjector(private val context: Context) {
      * preview passes "gearslip-preview".
      */
     fun start(
-        surface: Surface,
+        surface: Surface?,
         width: Int,
         height: Int,
         densityDpi: Int,
@@ -96,7 +99,7 @@ class ScreenProjector(private val context: Context) {
         decor.setViewTreeViewModelStoreOwner(treeOwner)
         decor.setBackgroundColor(Color.BLACK)
 
-        show.setContentView(ComposeView(show.context).apply { setContent(content) })
+        show.setContentView(ComposeView(withAppLanguage(show.context)).apply { setContent(content) })
         show.show()
 
         presentation = show
@@ -106,6 +109,18 @@ class ScreenProjector(private val context: Context) {
         GearslipLog.i("projecting ${width}x$height @ ${densityDpi}dpi")
     }
 
+    /**
+     * [context] in the language the driver picked for Gearslip, when it differs from the phone's
+     * (issue #80). Android builds a virtual display's context from the system locale and leaves
+     * the per-app one out, so the car screen stayed in the phone's language.
+     */
+    private fun withAppLanguage(context: Context): Context {
+        val locales = this.context.getSystemService(LocaleManager::class.java)?.applicationLocales
+        if (locales == null || locales.isEmpty) return context
+        val config = Configuration(context.resources.configuration).apply { setLocales(locales) }
+        return ContextThemeWrapper(context, context.theme).apply { applyOverrideConfiguration(config) }
+    }
+
     /** The projected display's id, for placing other apps' activities on it. */
     val displayId: Int? get() = virtualDisplay?.display?.displayId
 
@@ -198,6 +213,12 @@ class ScreenProjector(private val context: Context) {
      */
     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
@@ -213,6 +234,19 @@ class ScreenProjector(private val context: Context) {
         target.dispatchKeyEvent(event)
     }
 
+    /**
+     * Points the display at another surface, or none, without restarting what it shows. The
+     * preview's SurfaceView comes and goes as the phone turns; the car UI on it carries on.
+     */
+    /** Draws the screen again as it is, which hands the display's consumer a new frame. */
+    fun redraw() {
+        root?.let { it.post { it.invalidate() } }
+    }
+
+    fun setSurface(surface: Surface?) {
+        virtualDisplay?.surface = surface
+    }
+
     fun stop() {
         runCatching { presentation?.dismiss() }
         runCatching { owner?.destroy() }

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

@@ -51,8 +51,17 @@ object ServiceDiscovery {
             "$resolutionName @ $frameRateName, density=$density, margin=${widthMargin}x$heightMargin"
     }
 
-    /** [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) {
+    /**
+     * [displayId] is MediaSinkService field 6: 0, the default, is the main screen. [displayType]
+     * is field 7 (0 main, 1 instrument cluster, 2 auxiliary), or null when the car leaves it out.
+     */
+    class VideoService(
+        val serviceId: Int,
+        val codecType: Int,
+        val configs: List<VideoConfig>,
+        val displayId: Int = 0,
+        val displayType: Int? = null,
+    ) {
         val codecName: String get() = CODECS[codecType] ?: "unknown($codecType)"
     }
 
@@ -76,7 +85,7 @@ object ServiceDiscovery {
     fun findAudioServices(response: ByteArray): List<AudioService> = buildList {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)
-            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val id = serviceId(service) ?: continue
             val sink = Wire.bytes(service, 3) ?: continue
             val sinkFields = Wire.fields(sink)
             val audioConfigs = Wire.allBytes(sinkFields, 3)
@@ -110,6 +119,40 @@ object ServiceDiscovery {
         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 channel the car takes call status on (PhoneStatusService, Service field 10), for its
+     * cluster and phone screens. It carries no settings. Null when the car has none.
+     */
+    fun findPhoneStatusChannel(response: ByteArray): Int? = findChannelWith(response, 10)
+
+    class NavStatusService(val serviceId: Int, val minimumIntervalMs: Int)
+
+    /** The cluster advertises its minimum update interval in NavigationStatusService field 1. */
+    fun findNavStatusService(response: ByteArray): NavStatusService? =
+        Wire.allBytes(Wire.fields(response), 1).firstNotNullOfOrNull { channel ->
+            val service = Wire.fields(channel)
+            val id = serviceId(service) ?: return@firstNotNullOfOrNull null
+            val navigation = Wire.bytes(service, 8) ?: return@firstNotNullOfOrNull null
+            val interval = Wire.varint(Wire.fields(navigation), 1) ?: return@firstNotNullOfOrNull null
+            if (interval !in 0L..Int.MAX_VALUE.toLong()) return@firstNotNullOfOrNull null
+            NavStatusService(id, interval.toInt())
+        }
+
+    private fun serviceId(fields: List<Wire.Field>): Int? =
+        Wire.varint(fields, 1)?.takeIf { it in 1L..255L }?.toInt()
+
+    private fun findChannelWith(response: ByteArray, serviceField: Int): Int? =
+        Wire.allBytes(Wire.fields(response), 1).firstNotNullOfOrNull { channel ->
+            val service = Wire.fields(channel)
+            if (Wire.bytes(service, serviceField) != null) serviceId(service) else null
+        }
+
     /**
      * The car's microphone, from MediaSourceService (Service field 5):
      *   MediaSourceService { MediaCodecType available_type = 1; AudioConfiguration audio_config = 2;
@@ -119,7 +162,7 @@ object ServiceDiscovery {
     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 id = serviceId(service) ?: continue
             val source = Wire.fields(Wire.bytes(service, 5) ?: continue)
             val f = Wire.fields(Wire.bytes(source, 2) ?: continue)
             return AudioService(
@@ -138,8 +181,50 @@ object ServiceDiscovery {
         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)
+        }
+
+    /** The channel of the car's Wi-Fi projection service (Service field 14), or null. */
+    fun findWifiProjectionService(response: ByteArray): Int? =
+        Wire.allBytes(Wire.fields(response), 1).firstNotNullOfOrNull { channel ->
+            val service = Wire.fields(channel)
+            if (Wire.bytes(service, 14) == null) null else Wire.varint(service, 1)?.toInt()
+        }
+
+    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 = Wire.repeatedInts(fields, 2)
+            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")
 
@@ -163,8 +248,8 @@ object ServiceDiscovery {
      *                         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. [keycodesSupported] is what the
+     * Touch reports use projected video coordinates; these dimensions describe the input
+     * hardware and help select a video configuration. [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.
@@ -193,38 +278,18 @@ object ServiceDiscovery {
     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 id = serviceId(service) ?: continue
             val input = Wire.bytes(service, 4) ?: continue
             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())
-            }
+            val keycodes = Wire.repeatedInts(inputFields, 1)
             add(InputService(id, width, height, keycodes, Wire.varint(inputFields, 5)?.toInt() ?: 0))
         }
     }
 
-    /** 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.
@@ -234,10 +299,23 @@ object ServiceDiscovery {
         return sinks.firstOrNull { it.displayId == 0 } ?: sinks.firstOrNull()
     }
 
+    /**
+     * The instrument cluster's video sink: one marked as a cluster, or, from a car that marks
+     * none, a second sink beside the main screen's. Null when the car has no cluster screen.
+     */
+    fun findClusterVideoService(response: ByteArray): VideoService? {
+        val sinks = videoServices(response)
+        val main = findVideoService(response) ?: return null
+        return sinks.firstOrNull { it.displayType == DISPLAY_TYPE_CLUSTER && it.serviceId != main.serviceId }
+            ?: sinks.firstOrNull { it.displayType == null && it.serviceId != main.serviceId && it.displayId != main.displayId }
+    }
+
+    private const val DISPLAY_TYPE_CLUSTER = 1
+
     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
+            val id = serviceId(service) ?: continue
             val sink = Wire.bytes(service, 3) ?: continue
 
             val sinkFields = Wire.fields(sink)
@@ -255,7 +333,7 @@ object ServiceDiscovery {
                     heightMargin = Wire.varint(f, 4)?.toInt() ?: 0,
                 )
             }
-            add(VideoService(id, codecType, configs, Wire.varint(sinkFields, 6)?.toInt() ?: 0))
+            add(VideoService(id, codecType, configs, Wire.varint(sinkFields, 6)?.toInt() ?: 0, Wire.varint(sinkFields, 7)?.toInt()))
         }
     }
 
@@ -264,16 +342,15 @@ object ServiceDiscovery {
      *   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.
+     * SensorBatch contains repeated messages in fields 1 through 22 matching these type ids.
+     * The vehicle data screen keeps their raw contents for diagnostics.
      */
     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 id = serviceId(service) ?: continue
             val sensorSource = Wire.bytes(service, 2) ?: continue
             val types = Wire.allBytes(Wire.fields(sensorSource), 1).mapNotNull {
                 Wire.varint(Wire.fields(it), 1)?.toInt()

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

@@ -18,6 +18,7 @@ object SessionReport {
     enum class Category(val label: String) {
         NONE("none"),
         USB("USB transport"),
+        WIFI("Wi-Fi transport"),
         NO_HANDSHAKE("head unit never started talking"),
         TLS("TLS handshake failed"),
         CERTIFICATE("certificate rejected by the head unit"),
@@ -29,12 +30,30 @@ object SessionReport {
         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 = ""
@@ -58,10 +77,17 @@ object SessionReport {
         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
@@ -69,34 +95,87 @@ object SessionReport {
         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 }
+    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 {
@@ -140,12 +219,19 @@ object SessionReport {
             // 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 && category in setOf(Category.NONE, Category.USB, Category.WIFI, 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) }
+            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

@@ -14,13 +14,16 @@ object SessionStatus {
 
     enum class Phase { IDLE, CONNECTING, PROJECTING, FAILED, DISCONNECTED }
 
-    data class Snapshot(val phase: Phase, val headline: String, val detail: String)
+    /** [stuckOn] is set when connecting has gone on too long: the cable or Wi-Fi, for what to try. */
+    data class Snapshot(val phase: Phase, val headline: String, val detail: String, val stuckOn: Link? = null)
+
+    enum class Link { CABLE, WIRELESS }
 
     private val flow = MutableStateFlow(
         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.",
         ),
     )
 
@@ -30,6 +33,12 @@ object SessionStatus {
         flow.value = Snapshot(Phase.CONNECTING, "Connecting", stage)
     }
 
+    /** Still connecting after [GearslipRunner]'s patience ran out: Home says what to try. */
+    fun stillConnecting(link: Link) {
+        val now = flow.value
+        if (now.phase == Phase.CONNECTING) flow.value = now.copy(stuckOn = link)
+    }
+
     fun projecting() {
         flow.value = Snapshot(Phase.PROJECTING, "Projecting", "Streaming to the head unit.")
     }

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

@@ -23,8 +23,16 @@ 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,
+    /**
+     * SURFACE mode, nothing encoded for [STILL_MS]. The repeat setting below should cover a still
+     * screen, but on a Pixel 10 it didn't: a LuChi box got 11 frames, then none, and stayed black
+     * (issue #58). Whoever draws the screen can draw it again, and that is a frame.
+     */
+    private val onStill: () -> Unit = {},
 ) {
     private val log = GearslipLog.tagged("VIDEO")
 
@@ -40,12 +48,25 @@ class VideoSource(
         private set
 
     private var codec: MediaCodec? = null
+
+    /** The bitrate the encoder started at, the most [setBitRate] ever goes back up to. */
+    var fullBitRate = 0
+        private set
+
+    /** What the encoder is asked for right now. */
+    @Volatile var bitRate = 0
+        private set
     private var worker: Thread? = null
     @Volatile private var running = false
     private var frameIndex = 0L
 
     fun start() {
-        val bitRate = (width.toLong() * height * frameRate * BITS_PER_PIXEL).toInt().coerceIn(MIN_BIT_RATE, MAX_BIT_RATE)
+        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
+        }
+        fullBitRate = bitRate
+        this.bitRate = bitRate
         fun format(tuned: Boolean) = MediaFormat.createVideoFormat(MIME, width, height).apply {
             setInteger(
                 MediaFormat.KEY_COLOR_FORMAT,
@@ -74,7 +95,7 @@ class VideoSource(
                 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)
@@ -98,7 +119,7 @@ class VideoSource(
         codec = encoder
         running = true
 
-        log.i("encoder started: ${width}x$height @ ${frameRate}fps, ${bitRate / 1000} kbps, H.264 Baseline, mode=$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) }
@@ -123,9 +144,28 @@ class VideoSource(
         }.onFailure { log.w("requestSyncFrame failed: ${it.message}") }
     }
 
+    /**
+     * Changes the bitrate while streaming, without a new keyframe or a restart. Used to back off
+     * when the car (or the Wi-Fi to it) can't keep up, and to climb back once it can.
+     */
+    fun setBitRate(bps: Int) {
+        val target = bps.coerceIn(fullBitRate / 4, fullBitRate)
+        if (target == bitRate) return
+        runCatching {
+            codec?.setParameters(Bundle().apply { putInt(MediaCodec.PARAMETER_KEY_VIDEO_BITRATE, target) })
+            bitRate = target
+        }.onFailure { log.w("setBitRate failed: ${it.message}") }
+    }
+
     fun stop() {
         running = false
-        worker?.join(1_000)
+        // Stop is called from threads that are themselves being shut down. An interrupt here
+        // used to escape as an uncaught exception and take the whole app down with the session.
+        try {
+            worker?.join(1_000)
+        } catch (e: InterruptedException) {
+            Thread.currentThread().interrupt()
+        }
         runCatching { inputSurface?.release() }
         inputSurface = null
         runCatching { codec?.stop() }
@@ -136,6 +176,8 @@ class VideoSource(
     private fun pump(encoder: MediaCodec) {
         val info = MediaCodec.BufferInfo()
         val frameIntervalUs = 1_000_000L / frameRate
+        var lastOutputAt = 0L
+        var lastNudgeAt = 0L
 
         while (running) {
             // SURFACE mode has no input buffers to fill - frames arrive from the display.
@@ -174,8 +216,16 @@ class VideoSource(
                     }
                 }
                 encoder.releaseOutputBuffer(outIndex, false)
+                lastOutputAt = System.currentTimeMillis()
                 outIndex = encoder.dequeueOutputBuffer(info, 0)
             }
+            if (mode == Mode.SURFACE && lastOutputAt > 0) {
+                val now = System.currentTimeMillis()
+                if (now - lastOutputAt > STILL_MS && now - lastNudgeAt > STILL_MS) {
+                    lastNudgeAt = now
+                    onStill()
+                }
+            }
 
             if (mode != Mode.SURFACE) Thread.sleep(maxOf(1L, frameIntervalUs / 2000))
         }
@@ -222,11 +272,50 @@ class VideoSource(
         const val MIME = MediaFormat.MIMETYPE_VIDEO_AVC
         const val TIMEOUT_US = 10_000L
         const val SURFACE_TIMEOUT_US = 100_000L
+        private const val STILL_MS = 1_000L
 
-        /** Enough for sharp text and map lines; 800x480 at 30fps comes out at 4 Mbps. */
-        const val BITS_PER_PIXEL = 0.3
-        const val MIN_BIT_RATE = 4_000_000
-        const val MAX_BIT_RATE = 12_000_000
+        /**
+         * 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
 

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

@@ -0,0 +1,103 @@
+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() }
+    }
+
+    companion object {
+        private const val INPUT_WAIT_US = 10_000L
+        private val FREQUENCIES = listOf(96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000, 12000, 11025, 8000, 7350)
+
+        /** The two-byte AudioSpecificConfig for AAC-LC: object type 2, rate index, channel count. */
+        fun audioSpecificConfig(sampleRate: Int, channels: Int): ByteArray {
+            val freq = FREQUENCIES.indexOf(sampleRate).let { if (it < 0) 3 else it }
+            return byteArrayOf(
+                ((2 shl 3) or (freq shr 1)).toByte(),
+                (((freq and 1) shl 7) or (channels shl 3)).toByte(),
+            )
+        }
+    }
+}

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

@@ -16,6 +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
 
@@ -147,12 +148,17 @@ 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()
             val startedAt = heardAt
             var everHeard = false
             var warnedSilent = false
+            var lastSound = startedAt
+            var silenceReported = false
             try {
                 record.startRecording()
                 GearslipLog.i("audio: capturing media playback at ${rate}Hz x$channels")
@@ -170,6 +176,14 @@ class AudioCaptureService : Service() {
                     }
                     if (peak > 0) everHeard = true
                     val now = System.currentTimeMillis()
+                    // A stretch of silence: CarAudio says why on the car if a blocking app is playing.
+                    if (peak > 0) {
+                        lastSound = now
+                        silenceReported = false
+                    } else if (!silenceReported && now - lastSound >= SILENCE_MS) {
+                        silenceReported = true
+                        CarAudio.silent(this@AudioCaptureService)
+                    }
                     val level = peak / 32768f
                     if (now - heardAt >= LEVEL_LOG_MS) {
                         GearslipLog.i("audio: peak %.3f".format(level))

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

@@ -4,6 +4,8 @@ import app.seb3thehacker.gearslip.GearslipLog
 import app.seb3thehacker.gearslip.Protobuf
 import app.seb3thehacker.gearslip.ServiceDiscovery
 import app.seb3thehacker.gearslip.Wire
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
 
 /**
  * The phone end of the head unit's media audio sink, the audio twin of the video channel:
@@ -22,6 +24,21 @@ 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 when it starts. Directions ask only around each announcement,
+     * through [askForSpeakers], and only when the music isn't already ours.
+     */
+    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 = {},
+    /** The car wants the speakers for a moment (a call, its own voice), and then [onGivenBack]. */
+    private val onPausedForNow: () -> Unit = {},
+    private val onGivenBack: () -> Unit = {},
 ) : CarAudio.Link {
 
     private var configIndex = 0
@@ -29,15 +46,40 @@ class AudioLink(
     @Volatile private var started = false
     @Volatile private var focusGranted = false
     @Volatile private var focusRequested = false
+    /** The car took the speakers for a moment, and we paused the phone's music until it's done. */
+    @Volatile private var pausedForNow = false
     @Volatile private var inFlight = 0
     // 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
+    /**
+     * Bytes of PCM per Data message, or 0 to send each capture read as it comes. Raised by
+     * [adaptChunkSize] for a car that acks fewer chunks than it plays.
+     */
+    @Volatile private var chunkBytes = 0
+    /** Capture reads gathered until they fill [chunkBytes]. Only the capture thread touches it. */
+    private val pending = java.io.ByteArrayOutputStream()
+    /** Set by a new stream, so the capture thread drops what an older one left in [pending]. */
+    @Volatile private var pendingStale = false
+    /** The size of the last chunk sent, for [adaptChunkSize] to know what each one holds. */
+    @Volatile private var lastPayloadBytes = 0
+    /** Acks that came while the window was full, and the time they took: the car's own pace. */
+    private var slowAcks = 0
+    private var slowAckMs = 0L
+    private var lastAckFull = false
+    private var stalls = 0
     private var chunks = 0
     private var bytes = 0L
     private var dropped = 0
     @Volatile private var configTimer: Thread? = null
+    /** Underflows the car reported this drive, and the silence still to slip in ahead of the next chunk. */
+    private var underflows = 0
+    @Volatile private var padMs = 0
+    @Volatile private var pendingPadMs = 0
     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
@@ -45,29 +87,89 @@ class AudioLink(
 
     val channelId get() = service.serviceId
 
+    /** Sending audio now, which for media means the car has handed us the speakers. */
+    val streaming get() = started
+
+    /** The car has set the sink up, so a stream can start. */
+    val isReady get() = ready
+
+    @Volatile private var holdsSpeakers = false
+    @Volatile private var focusAnswer: CountDownLatch? = null
+    @Volatile private var answerDueBy = 0L
+
+    /** True just after [askForSpeakers] or [handBackSpeakers], when the car's next focus answer is ours. */
+    fun expectsFocusAnswer() = System.currentTimeMillis() < answerDueBy
+
+    /**
+     * For directions when nothing of ours is playing, so the car's speakers belong to the radio
+     * or a Bluetooth phone. Android Auto asks for them before each announcement, letting the
+     * other source duck, and hands them back afterwards. Speaking without asking left a 2025
+     * Nissan's Bosch head unit rebooting mid-drive (issue #35).
+     *
+     * Waits briefly for the car's answer and speaks anyway without one, as some cars never answer.
+     */
+    fun askForSpeakers() {
+        if (holdsSpeakers) return
+        val answer = CountDownLatch(1)
+        focusAnswer = answer
+        answerDueBy = System.currentTimeMillis() + FOCUS_WAIT_MS
+        holdsSpeakers = true
+        sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_GAIN_TRANSIENT_MAY_DUCK.toLong()))
+        GearslipLog.i("$tag: -> AudioFocusRequest(GAIN_TRANSIENT_MAY_DUCK)")
+        if (!answer.await(FOCUS_WAIT_MS, TimeUnit.MILLISECONDS)) {
+            GearslipLog.i("$tag: no focus answer after ${FOCUS_WAIT_MS}ms - speaking anyway")
+        }
+        focusAnswer = null
+    }
+
+    /** Gives back what [askForSpeakers] took, so the other source comes back to full volume. */
+    fun handBackSpeakers() {
+        if (!holdsSpeakers) return
+        holdsSpeakers = false
+        answerDueBy = System.currentTimeMillis() + FOCUS_WAIT_MS
+        runCatching { sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_RELEASE.toLong())) }
+        GearslipLog.i("$tag: -> AudioFocusRequest(RELEASE)")
+    }
+
+    /**
+     * A spoken turn on the music channel while no music plays (see DirectionsVoice): the stream
+     * runs for the turn only, under ducking focus like the directions channel's, so the radio
+     * comes back after it rather than giving way to Android Auto for good.
+     */
+    fun startForTurn() {
+        askForSpeakers()
+        startStream()
+    }
+
+    fun stopForTurn() {
+        synchronized(startLock) { stopLocked(release = false) }
+        handBackSpeakers()
+    }
+
     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({
@@ -76,19 +178,25 @@ 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)
@@ -98,34 +206,48 @@ 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",
                     )
                 }
             }
 
+            MSG_UNDERFLOW -> onUnderflow()
+
             MSG_ACK -> {
                 val acked = Wire.varint(Wire.fields(body), 2)?.toInt() ?: 1
+                val now = System.currentTimeMillis()
                 synchronized(ackLock) {
+                    // A full window means the sender is waiting on this ack. When it was waiting on
+                    // the one before too, the gap between them is the car's own pace.
+                    val full = inFlight >= maxUnacked
+                    if (full && lastAckFull) {
+                        slowAcks++
+                        slowAckMs += now - lastAckAt
+                    }
+                    lastAckFull = full
                     inFlight = maxOf(0, inFlight - maxOf(1, acked))
-                    lastAckAt = System.currentTimeMillis()
+                    lastAckAt = now
                     ackLock.notifyAll()
                 }
+                adaptChunkSize()
             }
 
-            // 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)
             }
         }
@@ -138,52 +260,221 @@ 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
-        if (focusGranted) startStream() else stop()
+        GearslipLog.i("$tag: <- AudioFocusResponse state=$name")
+        if (!asksFocus || expectsFocusAnswer()) {
+            // Directions speak whatever the answer: a lost turn is worse than a loud one.
+            answerDueBy = 0L
+            focusAnswer?.countDown()
+            return
+        }
+        val had = focusGranted
+        focusGranted = state == FOCUS_STATE_GAIN || state == FOCUS_STATE_GAIN_TRANSIENT ||
+            state == FOCUS_STATE_GAIN_MEDIA_ONLY
+        when {
+            focusGranted -> {
+                startStream()
+                if (pausedForNow) {
+                    pausedForNow = false
+                    onGivenBack()
+                }
+            }
+            // A call or the car's own voice. Releasing focus here meant the car never handed it
+            // back, so the music stayed paused after the call: keep the claim and wait for GAIN.
+            state == FOCUS_STATE_LOSS_TRANSIENT -> {
+                synchronized(startLock) { stopLocked(release = false) }
+                if (had) {
+                    pausedForNow = true
+                    onPausedForNow()
+                }
+            }
+            else -> {
+                stop()
+                // A ducking request leaves the music playing; a loss means another source has the speakers.
+                if (state == FOCUS_STATE_LOSS && (had || pausedForNow)) {
+                    pausedForNow = false
+                    onTakenBack()
+                }
+            }
+        }
     }
 
+    /**
+     * The car ran out of sound to play (AudioUnderflowNotification, no body): its buffer emptied
+     * before the next chunk arrived, which the driver hears as a gap. Capture runs in real time, so
+     * the car's buffer only ever holds what the window lets through. A little silence slipped in
+     * ahead of the next chunk puts it that far ahead, so the next slow patch is soaked up rather
+     * than heard. Capped, as each step adds a little delay to the music.
+     */
+    private fun onUnderflow() {
+        underflows++
+        val step = if (started && padMs < MAX_PAD_MS) PAD_STEP_MS else 0
+        padMs += step
+        pendingPadMs += step
+        if (underflows <= 3 || underflows % 20 == 0) {
+            GearslipLog.w("$tag: <- AudioUnderflow ($underflows this drive) - running ${padMs}ms ahead now")
+        }
+    }
+
+    /**
+     * A 2020 Civic acks a chunk about every 83 ms whatever the chunk holds, so 21 ms chunks
+     * reached it at a quarter of real time: a second of music, then silence, over and over
+     * (issue #43). When the car keeps the sender waiting and its acks come much further apart
+     * than the audio in each chunk, gather the capture into chunks that last at least that gap,
+     * rounded up to a power of two in frames: 83 ms is about 4096 frames at 48 kHz, which looks
+     * like the car's own buffer. A car that keeps up never fills the window, so it never gets here.
+     */
+    private fun adaptChunkSize() {
+        if (aac != null) return
+        val interval = synchronized(ackLock) {
+            if (slowAcks < ADAPT_ACKS) return
+            (slowAckMs.toDouble() / slowAcks).also {
+                slowAcks = 0
+                slowAckMs = 0
+            }
+        }
+        val frame = channels * 2
+        val bytesPerMs = sampleRate * frame / 1000.0
+        val current = if (chunkBytes > 0) chunkBytes else lastPayloadBytes
+        if (current <= 0 || current >= MAX_CHUNK_BYTES) return
+        val heldMs = current / bytesPerMs
+        if (interval < heldMs * SLOW_ACK_RATIO) return
+        val gapFrames = Math.ceil(interval * sampleRate / 1000.0).toInt().coerceAtLeast(1)
+        val frames = Integer.highestOneBit(gapFrames).let { if (it < gapFrames) it shl 1 else it }
+        val target = minOf(MAX_CHUNK_BYTES / frame * frame, frames * frame)
+        if (target <= current) return
+        chunkBytes = target
+        GearslipLog.i(
+            "$tag: the car acks a chunk every ${interval.toInt()}ms, but each holds ${heldMs.toInt()}ms - " +
+                "sending $target-byte chunks (${(target / bytesPerMs).toInt()}ms) from now on",
+        )
+    }
+
+    /** Silence for [ms], whole frames of this sink's format. */
+    private fun silence(ms: Int): ByteArray = ByteArray(sampleRate * ms / 1000 * channels * 2)
+
     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.
         startStream()
     }
 
+    /**
+     * Guards starting and stopping. [start] starts the stream at once for head units that never
+     * answer the focus request, and the car's answer arrives on another thread and starts it
+     * too: without this both got through, so the car got Start twice and two AAC encoders, and a
+     * 2014 head unit dropped the connection on the first audio.
+     */
+    private val startLock = Any()
+
     private fun startStream() {
+        synchronized(startLock) { startStreamLocked() }
+    }
+
+    private fun startStreamLocked() {
         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()),
         )
+        // Raw AAC-LC has no header of its own: the car needs the codec config before the first frame.
+        if (service.codecType == ServiceDiscovery.CODEC_AAC_LC) {
+            val asc = AacEncoder.audioSpecificConfig(sampleRate, channels)
+            sendOnChannel(MSG_CODEC_CONFIG, asc)
+            GearslipLog.hex("$tag: -> CodecConfig (AudioSpecificConfig)", asc)
+        }
         inFlight = 0
         lastAckAt = System.currentTimeMillis()
+        pendingStale = true
+        synchronized(ackLock) {
+            slowAcks = 0
+            slowAckMs = 0
+            lastAckFull = false
+        }
+        if (aacSink && aac == null) {
+            aac = runCatching { AacEncoder(sampleRate, channels, adts = service.codecType == ServiceDiscovery.CODEC_AAC_LC_ADTS) }
+                .onSuccess { GearslipLog.i("$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() {
+        synchronized(startLock) { stopLocked() }
+    }
+
+    /** [release] false keeps our claim on the speakers, so the car hands them back on its own. */
+    private fun stopLocked(release: Boolean = true) {
         if (!started) return
         started = false
         synchronized(ackLock) { ackLock.notifyAll() }
         runCatching {
-            sendOnChannel(MSG_STOP, Protobuf.varintField(1, SESSION_ID.toLong()))
-            if (focusRequested) sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_RELEASE.toLong()))
+            sendOnChannel(MSG_STOP, Protobuf.varintField(1, sessionId.toLong()))
+            if (release && focusRequested) sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_RELEASE.toLong()))
         }
-        focusRequested = false
+        if (release) focusRequested = false
         focusGranted = false
-        GearslipLog.i("audio: -> Stop, AudioFocusRequest(RELEASE) after $chunks chunks / $bytes bytes")
+        aac?.release()
+        aac = null
+        GearslipLog.i("$tag: -> Stop${if (release) ", AudioFocusRequest(RELEASE)" else ""} after $chunks chunks / $bytes bytes")
         chunks = 0
         bytes = 0
+        // A new stream starts with the car's buffer empty again: earn the lead back if it's needed.
+        padMs = 0
+        pendingPadMs = 0
     }
 
     override fun write(pcm: ByteArray, size: Int) {
         if (!started) return
+        val pad = pendingPadMs
+        if (pad > 0) {
+            pendingPadMs = 0
+            val quiet = silence(pad)
+            writeNow(quiet, quiet.size)
+        }
+        writeNow(pcm, size)
+    }
+
+    private fun writeNow(pcm: ByteArray, size: Int) {
+        val encoder = aac
+        if (encoder == null) {
+            if (pendingStale) {
+                pendingStale = false
+                pending.reset()
+            }
+            val want = chunkBytes
+            if (want <= 0 && pending.size() == 0) {
+                send(pcm.copyOf(size))
+                return
+            }
+            pending.write(pcm, 0, size)
+            if (pending.size() >= want) {
+                send(pending.toByteArray())
+                pending.reset()
+            }
+            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) {
@@ -191,7 +482,11 @@ class AudioLink(
                 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.
-                    GearslipLog.w("audio: no ack for ${STALL_MS}ms with $inFlight in flight - reopening the window")
+                    // A car that never acks (the 2024 VW, the Bolt) hits this every chunk: say so
+                    // once, then now and then, so the rest of the log stays readable.
+                    if (stalls++ % 500 == 0) {
+                        GearslipLog.w("$tag: no ack for ${STALL_MS}ms with $inFlight in flight - reopening the window ($stalls times)")
+                    }
                     inFlight = 0
                     break
                 }
@@ -206,20 +501,21 @@ class AudioLink(
         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
         }
         synchronized(ackLock) { inFlight++ }
+        lastPayloadBytes = payload.size
         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"}",
             )
         }
@@ -229,8 +525,9 @@ class AudioLink(
         configTimer?.interrupt()
         configTimer = null
         stop()
+        handBackSpeakers()
         ready = false
-        CarAudio.detach(this)
+        onClose(this)
     }
 
     companion object {
@@ -238,23 +535,41 @@ class AudioLink(
         const val MSG_FOCUS_RESPONSE = 19
         private const val MSG_CHANNEL_OPEN_RESPONSE = 8
         private const val MSG_DATA = 0
+        private const val MSG_CODEC_CONFIG = 1
         private const val MSG_SETUP = 32768
         private const val MSG_START = 32769
         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 MSG_UNDERFLOW = 32779 // 0x800B, car to phone, no body
+        private const val PAD_STEP_MS = 60
+        private const val MAX_PAD_MS = 240
         private const val STATUS_READY = 2
         private const val FOCUS_GAIN = 1
+        private const val FOCUS_GAIN_TRANSIENT_MAY_DUCK = 3
         private const val FOCUS_RELEASE = 4
+        private const val FOCUS_WAIT_MS = 500L
         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
+        /** Acks measured with the window full before the chunk size is judged. */
+        private const val ADAPT_ACKS = 20
+        /** Acks this much further apart than a chunk lasts mean the car is the one holding back. */
+        private const val SLOW_ACK_RATIO = 1.5
+        /** About 170 ms at 48 kHz stereo: the most delay a bigger chunk may add. */
+        private const val MAX_CHUNK_BYTES = 32_768
         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

@@ -44,11 +44,31 @@ object CarAudio {
 
     @Volatile private var link: Link? = null
 
+    /** Opens the car's media channel, left closed while music went over Bluetooth; null once open. */
+    @Volatile var openSink: (() -> Unit)? = null
+
+    /** The car offers a music channel, open or waiting to be. */
+    val sinkOffered: Boolean get() = link != null || openSink != null
+
     /** Rate and channel count the capture should use: the car's, or a sensible default. */
     val sampleRate get() = link?.sampleRate ?: 48_000
     val channels get() = link?.channels ?: 2
 
+    private val main by lazy { android.os.Handler(android.os.Looper.getMainLooper()) }
+
+    /**
+     * The car left and none came back: stop capturing, which ends the screen sharing Android
+     * shows for it and gives the phone its speaker back. Nothing else stopped it once the drive
+     * was over; with a wireless dongle Gearslip's screen stays open, so it ran on (issue #43).
+     */
+    private val releaseWhenGone = Runnable {
+        if (link != null || _capture.value == Capture.OFF) return@Runnable
+        GearslipLog.i("audio: no car for ${CAR_GONE_MS / 1000}s - stopping the capture and screen sharing")
+        release()
+    }
+
     fun attach(link: Link) {
+        main.removeCallbacks(releaseWhenGone)
         this.link = link
         GearslipLog.i("audio: the car offered a sink at ${link.sampleRate}Hz x${link.channels}")
         when {
@@ -57,10 +77,24 @@ object CarAudio {
         }
     }
 
+    /**
+     * The car's music channel closed. A car that comes straight back (a cable that slips) keeps
+     * the capture it had, so the driver isn't asked again mid-drive.
+     */
     fun detach(link: Link) {
-        if (this.link === link) this.link = null
+        if (this.link !== link) return
+        this.link = null
+        main.removeCallbacks(releaseWhenGone)
+        main.postDelayed(releaseWhenGone, CAR_GONE_MS)
     }
 
+    /**
+     * How long after the car leaves the capture waits for it to come back: a cable that slips, or a
+     * wireless link that drops and reconnects, which can take well over 3 seconds. Stopping sooner
+     * would have Android ask the driver to share the screen again in the middle of a drive.
+     */
+    private const val CAR_GONE_MS = 30_000L
+
     /**
      * The car wants sound. Safe to call as often as the session likes: the consent dialog appears
      * at most once, and only once there is a sink to play through - asking on the bench, where the
@@ -71,6 +105,7 @@ object CarAudio {
         when (_capture.value) {
             Capture.ON, Capture.ASKING, Capture.DENIED -> return
             Capture.OFF -> if (link == null) {
+                openSink?.invoke()
                 GearslipLog.i("audio: waiting for the car to offer an audio sink")
             } else {
                 ask()
@@ -89,9 +124,30 @@ object CarAudio {
         }
     }
 
+    /**
+     * Capture has heard nothing for a while. If a media app that blocks capture is the one
+     * playing, the car screen says why the music is silent, once a drive: Spotify does this.
+     */
+    internal fun silent(context: android.content.Context) = android.os.Handler(android.os.Looper.getMainLooper()).post {
+        if (toldBlocked) return@post
+        val media = app.seb3thehacker.gearslip.car.CarServices.mediaOrNull() ?: return@post
+        if (!media.now.value.playing) return@post
+        val name = BLOCKS_CAPTURE[media.packageName] ?: return@post
+        toldBlocked = true
+        GearslipLog.i("audio: $name is playing and capture hears nothing: it blocks other apps from playing its sound")
+        app.seb3thehacker.gearslip.car.CarToasts.show(this, context.getString(app.seb3thehacker.gearslip.R.string.car_audio_blocked, name), androidx.car.app.CarToast.LENGTH_LONG)
+    }
+
+    @Volatile private var toldBlocked = false
+
+    /** Media apps known to keep other apps from capturing their sound, by package. */
+    private val BLOCKS_CAPTURE = mapOf("com.spotify.music" to "Spotify")
+
     /** The car went away. Everything is torn down; the next connection asks again. */
     fun release() {
+        main.removeCallbacks(releaseWhenGone)
         wanted = false
+        toldBlocked = false
         AudioCaptureService.stop()
         _capture.value = Capture.OFF
     }
@@ -100,6 +156,26 @@ 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()
@@ -113,6 +189,59 @@ object CarAudio {
 
     internal fun deliver(pcm: ByteArray, size: Int, peak: Float) {
         _level.value = peak
-        link?.write(pcm, size)
+        val voice = synchronized(voiceLock) { spoken }
+        if (voice == null) link?.write(pcm, size) else link?.write(mixVoice(pcm, size), size)
     }
+
+    private val voiceLock = Any()
+    private var spoken: ByteArray? = null
+    private var spokenAt = 0
+    private var spokenDone: java.util.concurrent.CountDownLatch? = null
+
+    /**
+     * Mixes a spoken turn into the music from the next chunk on, with the music turned down
+     * under it, and waits until it has all gone out. [pcm] is 16-bit, in the sink's own format.
+     * False when no music is flowing to carry it, so the caller sends it some other way.
+     */
+    fun speakOverMusic(pcm: ByteArray): Boolean {
+        if (_capture.value != Capture.ON || (link as? AudioLink)?.streaming != true) return false
+        val done = java.util.concurrent.CountDownLatch(1)
+        synchronized(voiceLock) {
+            spokenDone?.countDown()
+            spoken = pcm
+            spokenAt = 0
+            spokenDone = done
+        }
+        val ms = pcm.size * 1000L / (2 * channels * sampleRate)
+        if (!done.await(ms + VOICE_SLACK_MS, java.util.concurrent.TimeUnit.MILLISECONDS)) {
+            // Capture stopped mid-turn; the rest of it is dropped rather than played late.
+            synchronized(voiceLock) { if (spokenDone === done) spoken = null }
+        }
+        return true
+    }
+
+    private fun mixVoice(pcm: ByteArray, size: Int): ByteArray = synchronized(voiceLock) {
+        val voice = spoken ?: return pcm
+        val out = pcm.copyOf(size)
+        var i = 0
+        while (i + 1 < size) {
+            val music = (out[i].toInt() and 0xFF) or (out[i + 1].toInt() shl 8)
+            val word = if (spokenAt + 1 < voice.size) (voice[spokenAt].toInt() and 0xFF) or (voice[spokenAt + 1].toInt() shl 8) else 0
+            val mixed = (music * DUCK_PERCENT / 100 + word).coerceIn(Short.MIN_VALUE.toInt(), Short.MAX_VALUE.toInt())
+            out[i] = mixed.toByte()
+            out[i + 1] = (mixed shr 8).toByte()
+            i += 2
+            spokenAt += 2
+        }
+        if (spokenAt >= voice.size) {
+            spoken = null
+            spokenDone?.countDown()
+            spokenDone = null
+        }
+        out
+    }
+
+    /** How loud the music stays under a spoken turn. */
+    private const val DUCK_PERCENT = 30
+    private const val VOICE_SLACK_MS = 2_000L
 }

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

@@ -12,17 +12,21 @@ import java.util.concurrent.TimeUnit
  *
  *   -> 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].
+ * 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
 
@@ -43,7 +47,8 @@ class CarMic(
                 val status = Protobuf.readInt32Field(body, 1) ?: 0
                 GearslipLog.i("mic: <- ChannelOpenResponse: status=$status")
                 if (status != 0) return
-                sendOnChannel(MSG_SETUP, Protobuf.varintField(1, 0L))
+                // 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(
@@ -97,6 +102,7 @@ class CarMic(
         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
@@ -109,7 +115,8 @@ class CarMic(
         if (!listening) return
         listening = false
         sendOnChannel(MSG_MIC_REQUEST, Protobuf.varintField(1, 0L))
-        GearslipLog.i("mic: -> MicrophoneRequest(close) after $packets packets")
+        voiceSession(false)
+        GearslipLog.i("mic: -> MicrophoneRequest(close) after $packets packets, voice session ended")
     }
 
     companion object {

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/BrowserSettings.kt

@@ -0,0 +1,212 @@
+package app.seb3thehacker.gearslip.browser
+
+import android.content.Context
+import android.content.SharedPreferences
+import java.net.URLEncoder
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import org.json.JSONArray
+import org.json.JSONObject
+
+/** A page saved to the browser's start page. */
+data class Bookmark(val title: String, val url: String) {
+    /** The host without "www.", for labels and icons. */
+    val host: String get() = runCatching { android.net.Uri.parse(url).host.orEmpty() }.getOrDefault("").removePrefix("www.")
+}
+
+/** Where typed searches go. [query] is the address with the search terms appended, encoded. */
+enum class SearchEngine(val id: String, val label: String, private val query: String) {
+    DUCKDUCKGO("duckduckgo", "DuckDuckGo", "https://duckduckgo.com/?q="),
+    STARTPAGE("startpage", "Startpage", "https://www.startpage.com/do/search?q="),
+    BRAVE("brave", "Brave Search", "https://search.brave.com/search?q="),
+    ECOSIA("ecosia", "Ecosia", "https://www.ecosia.org/search?q="),
+    GOOGLE("google", "Google", "https://www.google.com/search?q="),
+    BING("bing", "Bing", "https://www.bing.com/search?q=");
+
+    fun search(text: String): String = query + URLEncoder.encode(text, "UTF-8")
+}
+
+/**
+ * A filter list the ad blocker can use: one of the two it ships with, or one the driver added by
+ * its address. [id] names the cached copy on disk.
+ */
+data class FilterList(val id: String, val title: String, val url: String, val builtIn: Boolean, val enabled: Boolean)
+
+/**
+ * The browser's own settings: bookmarks, the search engine, and the ad blocker's switches and
+ * lists. Kept in a preferences file of their own and mirrored into flows, so the car's browser
+ * and the phone's settings show the same thing. The ad blocker reads only the flows' values,
+ * never the file, since it answers on WebView's request thread (see [adblock.AdBlockManager]).
+ */
+object BrowserSettings {
+
+    private const val FILE = "browser"
+    private const val KEY_BOOKMARKS = "bookmarks"
+    private const val KEY_SEARCH = "search_engine"
+    private const val KEY_ADBLOCK = "adblock"
+    private const val KEY_YOUTUBE = "adblock_youtube"
+    private const val KEY_LISTS_OFF = "adblock_lists_off"
+    private const val KEY_CUSTOM_LISTS = "adblock_custom_lists"
+    private const val KEY_LAST_CHECK = "adblock_last_check"
+
+    /** The lists Gearslip ships a snapshot of, on unless turned off. */
+    val BUILT_IN_LISTS = listOf(
+        FilterList("easylist", "EasyList", "https://easylist.to/easylist/easylist.txt", builtIn = true, enabled = true),
+        FilterList("easyprivacy", "EasyPrivacy", "https://easylist.to/easylist/easyprivacy.txt", builtIn = true, enabled = true),
+    )
+
+    /** What a new install's start page offers, until the driver changes it. */
+    private val DEFAULT_BOOKMARKS = listOf(
+        Bookmark("YouTube", "https://m.youtube.com"),
+        Bookmark("Wikipedia", "https://en.m.wikipedia.org"),
+    )
+
+    private val bookmarksFlow = MutableStateFlow<List<Bookmark>>(emptyList())
+    private val searchFlow = MutableStateFlow(SearchEngine.DUCKDUCKGO)
+    private val adBlockFlow = MutableStateFlow(true)
+    private val youTubeFlow = MutableStateFlow(true)
+    private val listsFlow = MutableStateFlow(BUILT_IN_LISTS)
+
+    val bookmarks: StateFlow<List<Bookmark>> = bookmarksFlow
+    val searchEngine: StateFlow<SearchEngine> = searchFlow
+    val adBlock: StateFlow<Boolean> = adBlockFlow
+    val youTubeAdBlock: StateFlow<Boolean> = youTubeFlow
+    val filterLists: StateFlow<List<FilterList>> = listsFlow
+
+    @Volatile private var prefs: SharedPreferences? = null
+
+    /** Loads everything once per process. Safe to call from anywhere that has a context. */
+    fun init(context: Context) {
+        if (prefs != null) return
+        synchronized(this) {
+            if (prefs != null) return
+            val p = context.applicationContext.getSharedPreferences(FILE, Context.MODE_PRIVATE)
+            bookmarksFlow.value = if (p.contains(KEY_BOOKMARKS)) readBookmarks(p.getString(KEY_BOOKMARKS, "[]").orEmpty()) else DEFAULT_BOOKMARKS
+            searchFlow.value = SearchEngine.entries.firstOrNull { it.id == p.getString(KEY_SEARCH, null) } ?: SearchEngine.DUCKDUCKGO
+            adBlockFlow.value = p.getBoolean(KEY_ADBLOCK, true)
+            youTubeFlow.value = p.getBoolean(KEY_YOUTUBE, true)
+            listsFlow.value = readLists(p)
+            prefs = p
+        }
+    }
+
+    // Bookmarks
+
+    fun isBookmarked(url: String?): Boolean = url != null && bookmarksFlow.value.any { same(it.url, url) }
+
+    /** Adds [url], or renames it when it's already saved. Returns false for something that isn't a web address. */
+    fun addBookmark(title: String, url: String): Boolean {
+        val clean = url.trim()
+        if (!clean.startsWith("http://") && !clean.startsWith("https://")) return false
+        val name = title.trim().ifEmpty { Bookmark("", clean).host.ifEmpty { clean } }
+        val list = bookmarksFlow.value
+        val existing = list.indexOfFirst { same(it.url, clean) }
+        saveBookmarks(if (existing >= 0) list.toMutableList().also { it[existing] = Bookmark(name, list[existing].url) } else list + Bookmark(name, clean))
+        return true
+    }
+
+    fun removeBookmark(url: String) = saveBookmarks(bookmarksFlow.value.filterNot { same(it.url, url) })
+
+    /** Moves the bookmark at [from] to [to], for reordering from the phone. */
+    fun moveBookmark(from: Int, to: Int) {
+        val list = bookmarksFlow.value.toMutableList()
+        if (from !in list.indices || to !in list.indices) return
+        list.add(to, list.removeAt(from))
+        saveBookmarks(list)
+    }
+
+    /** The same page whatever the trailing slash or scheme. */
+    private fun same(a: String, b: String): Boolean {
+        fun key(u: String) = u.trim().removePrefix("https://").removePrefix("http://").removePrefix("www.").trimEnd('/')
+        return key(a).equals(key(b), ignoreCase = true)
+    }
+
+    private fun saveBookmarks(list: List<Bookmark>) {
+        bookmarksFlow.value = list
+        val array = JSONArray()
+        list.forEach { array.put(JSONObject().put("title", it.title).put("url", it.url)) }
+        prefs?.edit()?.putString(KEY_BOOKMARKS, array.toString())?.apply()
+    }
+
+    private fun readBookmarks(json: String): List<Bookmark> = runCatching {
+        val array = JSONArray(json)
+        (0 until array.length()).map { array.getJSONObject(it) }.map { Bookmark(it.optString("title"), it.optString("url")) }
+            .filter { it.url.isNotEmpty() }
+    }.getOrDefault(emptyList())
+
+    // Search
+
+    fun setSearchEngine(engine: SearchEngine) {
+        searchFlow.value = engine
+        prefs?.edit()?.putString(KEY_SEARCH, engine.id)?.apply()
+    }
+
+    /** Something that looks like an address opens as one; anything else is searched for. */
+    fun addressToUrl(typed: String): String {
+        val text = typed.trim()
+        return when {
+            text.startsWith("http://") || text.startsWith("https://") -> text
+            ' ' !in text && '.' in text -> "https://$text"
+            else -> searchFlow.value.search(text)
+        }
+    }
+
+    // Ad blocking
+
+    fun setAdBlock(on: Boolean) {
+        adBlockFlow.value = on
+        prefs?.edit()?.putBoolean(KEY_ADBLOCK, on)?.apply()
+    }
+
+    fun setYouTubeAdBlock(on: Boolean) {
+        youTubeFlow.value = on
+        prefs?.edit()?.putBoolean(KEY_YOUTUBE, on)?.apply()
+    }
+
+    fun setListEnabled(id: String, on: Boolean) {
+        val p = prefs ?: return
+        val off = p.getStringSet(KEY_LISTS_OFF, emptySet()).orEmpty().toMutableSet()
+        if (on) off.remove(id) else off.add(id)
+        p.edit().putStringSet(KEY_LISTS_OFF, off).apply()
+        listsFlow.value = readLists(p)
+    }
+
+    /** Adds a list by its address. Returns false for something that isn't one, or one already there. */
+    fun addCustomList(url: String): Boolean {
+        val p = prefs ?: return false
+        val clean = url.trim()
+        if (!clean.startsWith("https://") && !clean.startsWith("http://")) return false
+        if (listsFlow.value.any { it.url.equals(clean, ignoreCase = true) }) return false
+        p.edit().putString(KEY_CUSTOM_LISTS, (customUrls(p) + clean).joinToString("\n")).apply()
+        listsFlow.value = readLists(p)
+        return true
+    }
+
+    fun removeCustomList(id: String) {
+        val p = prefs ?: return
+        val list = listsFlow.value.firstOrNull { it.id == id && !it.builtIn } ?: return
+        p.edit().putString(KEY_CUSTOM_LISTS, customUrls(p).filterNot { it == list.url }.joinToString("\n")).apply()
+        listsFlow.value = readLists(p)
+    }
+
+    var lastUpdateCheck: Long
+        get() = prefs?.getLong(KEY_LAST_CHECK, 0L) ?: 0L
+        set(value) { prefs?.edit()?.putLong(KEY_LAST_CHECK, value)?.apply() }
+
+    private fun customUrls(p: SharedPreferences) = p.getString(KEY_CUSTOM_LISTS, "").orEmpty().lines().filter { it.isNotBlank() }
+
+    private fun readLists(p: SharedPreferences): List<FilterList> {
+        val off = p.getStringSet(KEY_LISTS_OFF, emptySet()).orEmpty()
+        val custom = customUrls(p).map { url ->
+            val name = runCatching { android.net.Uri.parse(url).lastPathSegment }.getOrNull()?.takeIf { it.isNotBlank() } ?: url
+            FilterList(customId(url), name, url, builtIn = false, enabled = true)
+        }
+        return (BUILT_IN_LISTS + custom).map { it.copy(enabled = it.id !in off) }
+    }
+
+    /** A stable file name for a list known only by its address. */
+    private fun customId(url: String): String {
+        val digest = java.security.MessageDigest.getInstance("SHA-256").digest(url.toByteArray())
+        return "custom-" + digest.take(8).joinToString("") { "%02x".format(it) }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/ShareToBrowserActivity.kt

@@ -0,0 +1,31 @@
+package app.seb3thehacker.gearslip.browser
+
+import android.app.Activity
+import android.content.Intent
+import android.os.Bundle
+import android.widget.Toast
+import app.seb3thehacker.gearslip.R
+
+/**
+ * The "Add to Gearslip" entry in Android's share sheet. A page shared from any browser becomes a
+ * tile on the car browser's start page, so nobody has to type an address on the car's keyboard.
+ * It shows nothing of its own: a toast says whether it worked, and it closes.
+ */
+class ShareToBrowserActivity : Activity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        BrowserSettings.init(this)
+        val text = intent?.takeIf { it.action == Intent.ACTION_SEND }?.getStringExtra(Intent.EXTRA_TEXT).orEmpty()
+        // Browsers share the bare address; some apps wrap it in a sentence, so take the first link.
+        val url = URL_PATTERN.find(text)?.value
+        val title = intent?.getStringExtra(Intent.EXTRA_SUBJECT) ?: intent?.getStringExtra(Intent.EXTRA_TITLE) ?: ""
+        val added = url != null && BrowserSettings.addBookmark(title, url)
+        Toast.makeText(this, getString(if (added) R.string.browser_shared_added else R.string.browser_shared_not_url), Toast.LENGTH_SHORT).show()
+        finish()
+    }
+
+    private companion object {
+        val URL_PATTERN = Regex("""https?://\S+""")
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/SiteIcons.kt

@@ -0,0 +1,91 @@
+package app.seb3thehacker.gearslip.browser
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import app.seb3thehacker.gearslip.GearslipLog
+import java.io.File
+import java.net.HttpURLConnection
+import java.net.URL
+import java.util.concurrent.ConcurrentHashMap
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * Each site's icon for the start page's tiles, kept on disk by host. The browser saves the icon
+ * a page hands it while loading ([save]); a bookmark that hasn't been opened yet asks its own
+ * site once ([fetch]), for its touch icon and then its favicon. Nothing goes to a third-party
+ * icon service, so no list of the driver's bookmarks leaves the phone.
+ */
+object SiteIcons {
+
+    private const val DIRECTORY = "site-icons"
+    /** Smaller than this is a 16px favicon that would look blurry on a tile; a bigger one wins. */
+    private const val GOOD_ENOUGH_PX = 96
+
+    private val memory = ConcurrentHashMap<String, Bitmap>()
+    private val asked = ConcurrentHashMap.newKeySet<String>()
+    private val changed = MutableStateFlow(0)
+
+    /** Bumps whenever an icon is saved, so tiles look again. */
+    val version: StateFlow<Int> = changed
+
+    fun icon(context: Context, host: String): Bitmap? {
+        if (host.isEmpty()) return null
+        memory[host]?.let { return it }
+        val file = file(context, host)
+        if (!file.isFile) return null
+        return runCatching { BitmapFactory.decodeFile(file.path) }.getOrNull()?.also { memory[host] = it }
+    }
+
+    /** An icon the page gave the browser. Kept when it's bigger than the one already saved. */
+    fun save(context: Context, host: String, bitmap: Bitmap) {
+        if (host.isEmpty()) return
+        val current = icon(context, host)
+        if (current != null && current.width >= bitmap.width) return
+        store(context, host, bitmap)
+    }
+
+    /** Asks [host] for its icon in the background, once per run, when none is saved or it's small. */
+    fun fetch(context: Context, host: String) {
+        if (host.isEmpty() || !asked.add(host)) return
+        val current = icon(context, host)
+        if (current != null && current.width >= GOOD_ENOUGH_PX) return
+        val app = context.applicationContext
+        Thread({
+            for (path in listOf("/apple-touch-icon.png", "/favicon.ico")) {
+                val bitmap = runCatching { download("https://$host$path") }.getOrNull() ?: continue
+                if (current == null || bitmap.width > current.width) store(app, host, bitmap)
+                return@Thread
+            }
+        }, "site-icon").apply { isDaemon = true }.start()
+    }
+
+    private fun store(context: Context, host: String, bitmap: Bitmap) {
+        memory[host] = bitmap
+        runCatching {
+            val file = file(context, host)
+            file.parentFile?.mkdirs()
+            file.outputStream().use { bitmap.compress(Bitmap.CompressFormat.PNG, 100, it) }
+        }.onFailure { GearslipLog.w("browser: couldn't save the icon for $host: ${it.message}") }
+        changed.value++
+    }
+
+    private fun download(url: String): Bitmap? {
+        val connection = (URL(url).openConnection() as HttpURLConnection).apply {
+            connectTimeout = 10_000
+            readTimeout = 10_000
+            instanceFollowRedirects = true
+        }
+        return try {
+            if (connection.responseCode !in 200..299) return null
+            val bytes = connection.inputStream.use { it.readBytes() }
+            BitmapFactory.decodeByteArray(bytes, 0, bytes.size)
+        } finally {
+            connection.disconnect()
+        }
+    }
+
+    private fun file(context: Context, host: String) =
+        File(File(context.filesDir, DIRECTORY), host.replace(Regex("[^A-Za-z0-9.-]"), "_") + ".png")
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/adblock/AdBlockManager.kt

@@ -0,0 +1,417 @@
+package app.seb3thehacker.gearslip.browser.adblock
+
+import android.content.Context
+import android.net.ConnectivityManager
+import android.net.NetworkCapabilities
+import android.util.Base64
+import android.webkit.WebResourceRequest
+import android.webkit.WebResourceResponse
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.browser.BrowserSettings
+import app.seb3thehacker.gearslip.browser.FilterList
+import java.io.ByteArrayInputStream
+import java.io.File
+import java.net.HttpURLConnection
+import java.net.URL
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicLong
+
+/**
+ * Owns the filter lists: downloading them, keeping a parsed [FilterEngine] in memory, and
+ * answering the two questions the WebView asks: block this request, and what to hide on
+ * this page.
+ *
+ * Everything the request path touches is cached in memory. `shouldInterceptRequest` runs on a
+ * background thread for every subresource on the page, so it must never read preferences or
+ * touch disk. The switches come from [BrowserSettings]'s flows, which are plain memory reads.
+ *
+ * Downloading a list contacts the server it comes from (easylist.to for the two built in), and
+ * nothing else: no page the driver visits is ever sent anywhere.
+ */
+object AdBlockManager {
+
+    sealed class RefreshResult {
+        data class Success(val networkRules: Int, val cosmeticRules: Int) : RefreshResult()
+        data class Failure(val message: String) : RefreshResult()
+    }
+
+    private const val DIRECTORY = "adblock"
+    private const val BUNDLED_ASSET = "adblock/bundled.txt"
+    private const val MAX_LIST_BYTES = 12L * 1024 * 1024
+
+    /**
+     * How stale the lists may get before the browser refreshes them on its own. EasyList
+     * publishes several times a day, but the parts that matter, the domains ads are served from,
+     * turn over slowly, and each update costs a few megabytes.
+     */
+    private const val UPDATE_INTERVAL_MS = 7L * 24 * 60 * 60 * 1000
+
+    // 1x1 transparent GIF, returned for blocked images so pages show a gap rather than a
+    // broken-image icon.
+    private const val TRANSPARENT_GIF_BASE64 =
+        "R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7"
+
+    private val EMPTY = ByteArray(0)
+    private val EMPTY_JSON = "{}".toByteArray()
+
+    val transparentGifBytes: ByteArray by lazy {
+        Base64.decode(TRANSPARENT_GIF_BASE64, Base64.DEFAULT)
+    }
+
+    @Volatile
+    private var engine: FilterEngine? = null
+
+    /** No per-site allowlist yet; kept so the request path reads the same as AABrowser's. */
+    private val allowlist: Set<String> = emptySet()
+
+    private val enabled: Boolean get() = BrowserSettings.adBlock.value
+    private val youTubeEnabled: Boolean get() = BrowserSettings.youTubeAdBlock.value
+
+    private val loadStarted = AtomicBoolean(false)
+    private val refreshRunning = AtomicBoolean(false)
+    private val autoUpdateAttempted = AtomicBoolean(false)
+    private val blockedCount = AtomicLong(0)
+    // Time spent deciding requests since the last page load, for the log line that tells whether
+    // the blocker is what makes a page or a video slow to start.
+    private val checkedCount = AtomicLong(0)
+    private val checkedNanos = AtomicLong(0)
+    private val blockedSincePage = AtomicLong(0)
+
+    val isEngineReady: Boolean get() = engine != null
+    val blockedRequestCount: Long get() = blockedCount.get()
+    val networkRuleCount: Int get() = engine?.networkRuleCount ?: 0
+    val cosmeticRuleCount: Int get() = engine?.cosmeticRuleCount ?: 0
+
+    /** Loads the cached lists from disk once per process, on a background thread. */
+    fun ensureInitialized(context: Context) {
+        BrowserSettings.init(context)
+        if (!enabled) return
+        if (!loadStarted.compareAndSet(false, true)) return
+
+        val appContext = context.applicationContext
+        Thread({
+            runCatching { loadFromDisk(appContext) }
+                .onFailure { GearslipLog.w("adblock: could not load the filter lists: ${it.message}") }
+        }, "adblock-load").apply {
+            // Blocking does nothing until this finishes, so it gets a normal share of the CPU.
+            // On a Pixel 6 a release build parses both lists in about 250ms.
+            priority = Thread.NORM_PRIORITY
+            start()
+        }
+    }
+
+    /** Rebuilds the engine from what's on disk after a list was turned on or off. */
+    fun reload(context: Context) {
+        val appContext = context.applicationContext
+        loadStarted.set(true)
+        Thread({ runCatching { loadFromDisk(appContext) } }, "adblock-load").start()
+    }
+
+    fun lastUpdatedAt(context: Context): Long =
+        BrowserSettings.filterLists.value.mapNotNull { cacheFile(context, it).takeIf { file -> file.length() > 0 } }
+            .maxOfOrNull { it.lastModified() } ?: 0L
+
+    private fun cacheFile(context: Context, source: FilterList): File =
+        File(File(context.filesDir, DIRECTORY), "${source.id}.txt")
+
+    private fun loadFromDisk(context: Context) {
+        val lists = BrowserSettings.filterLists.value.filter { it.enabled }
+        val files = lists.map { cacheFile(context, it) }.filter { it.length() > 0 }
+        val builder = FilterEngine.Builder()
+
+        // A built-in list that hasn't downloaded yet comes from the snapshot in the APK, so
+        // blocking works on the very first page rather than only after a download.
+        val needsBundled = lists.any { it.builtIn && cacheFile(context, it).length() == 0L }
+        if (needsBundled) {
+            context.assets.open(BUNDLED_ASSET).bufferedReader(Charsets.UTF_8).use { reader ->
+                while (true) {
+                    val line = reader.readLine() ?: break
+                    builder.addLine(line)
+                }
+            }
+        }
+
+        for (file in files) {
+            file.bufferedReader(bufferSize = 64 * 1024).use { reader ->
+                while (true) {
+                    val line = reader.readLine() ?: break
+                    builder.addLine(line)
+                }
+            }
+        }
+        engine = builder.finish()
+        GearslipLog.i("adblock: ${networkRuleCount} network and ${cosmeticRuleCount} hiding rules from ${lists.size} lists")
+    }
+
+    /** Downloads every list that's on, replaces the cached copies, and rebuilds the engine. */
+    fun refreshLists(context: Context): RefreshResult {
+        // The automatic refresh and the button in settings can both land here; two downloads
+        // writing the same files would leave one of them truncated.
+        val appContext = context.applicationContext
+        if (!refreshRunning.compareAndSet(false, true)) {
+            return RefreshResult.Failure("An update is already running.")
+        }
+        return try {
+            refresh(appContext).also {
+                // A manual update counts as a check, so the automatic one waits a full interval.
+                if (it is RefreshResult.Success) BrowserSettings.lastUpdateCheck = System.currentTimeMillis()
+            }
+        } finally {
+            refreshRunning.set(false)
+        }
+    }
+
+    /**
+     * Updates the lists when they have gone stale and the phone is on Wi-Fi, on a background
+     * thread. Runs when the car's browser opens; there is no scheduled job. Only one attempt per
+     * process, and the time is written on success alone, so a phone that was offline tries again
+     * next time rather than in a week.
+     */
+    fun refreshIfDue(context: Context) {
+        val appContext = context.applicationContext
+        BrowserSettings.init(appContext)
+        if (!enabled || !isUpdateDue(appContext) || !onUnmeteredNetwork(appContext)) return
+        if (!autoUpdateAttempted.compareAndSet(false, true)) return
+        Thread({
+            val result = refreshLists(appContext)
+            GearslipLog.i("adblock: weekly list update - $result")
+        }, "adblock-update").start()
+    }
+
+    private fun isUpdateDue(context: Context): Boolean {
+        val now = System.currentTimeMillis()
+        val lastCheck = BrowserSettings.lastUpdateCheck
+        if (lastCheck > 0 && now - lastCheck < UPDATE_INTERVAL_MS) return false
+        val baseline = lastUpdatedAt(context)
+        // Nothing downloaded yet: the snapshot in the APK may be months old, so fetch now.
+        if (baseline <= 0L) return true
+        // A clock that has jumped backwards would otherwise freeze the lists indefinitely.
+        if (baseline > now) return true
+        return now - baseline >= UPDATE_INTERVAL_MS
+    }
+
+    private fun onUnmeteredNetwork(context: Context): Boolean {
+        val manager = context.getSystemService(ConnectivityManager::class.java) ?: return false
+        val caps = manager.getNetworkCapabilities(manager.activeNetwork) ?: return false
+        return caps.hasCapability(NetworkCapabilities.NET_CAPABILITY_NOT_METERED)
+    }
+
+    private fun refresh(context: Context): RefreshResult {
+        val directory = File(context.filesDir, DIRECTORY)
+        if (!directory.exists() && !directory.mkdirs()) {
+            return RefreshResult.Failure("Could not create the filter list folder.")
+        }
+
+        for (source in BrowserSettings.filterLists.value.filter { it.enabled }) {
+            val result = runCatching { download(source, cacheFile(context, source)) }
+            val error = result.exceptionOrNull()
+            if (error != null) return RefreshResult.Failure("${source.title}: ${error.message ?: "download failed"}")
+            val failure = result.getOrNull()
+            if (failure != null) return RefreshResult.Failure("${source.title}: $failure")
+        }
+
+        loadStarted.set(true)
+        val loadError = runCatching { loadFromDisk(context) }.exceptionOrNull()
+        if (loadError != null) return RefreshResult.Failure(loadError.message ?: "Could not read the lists.")
+
+        val current = engine ?: return RefreshResult.Failure("The lists downloaded but contained no rules.")
+        return RefreshResult.Success(current.networkRuleCount, current.cosmeticRuleCount)
+    }
+
+    /** Returns null on success, or a human-readable reason for failure. */
+    private fun download(source: FilterList, destination: File): String? {
+        val connection = (URL(source.url).openConnection() as HttpURLConnection).apply {
+            connectTimeout = 15_000
+            readTimeout = 30_000
+            setRequestProperty("Accept", "text/plain")
+        }
+        try {
+            if (connection.responseCode !in 200..299) return "HTTP ${connection.responseCode}"
+            val temporary = File(destination.parentFile, destination.name + ".tmp")
+            var total = 0L
+
+            temporary.outputStream().use { output ->
+                connection.inputStream.use { input ->
+                    val buffer = ByteArray(16 * 1024)
+                    while (true) {
+                        val read = input.read(buffer)
+                        if (read < 0) break
+                        total += read
+                        if (total > MAX_LIST_BYTES) {
+                            temporary.delete()
+                            return "list is unexpectedly large"
+                        }
+                        output.write(buffer, 0, read)
+                    }
+                }
+            }
+
+            if (total == 0L) {
+                temporary.delete()
+                return "empty response"
+            }
+            if (!temporary.renameTo(destination)) {
+                temporary.delete()
+                return "could not save the list"
+            }
+        } finally {
+            connection.disconnect()
+        }
+        return null
+    }
+
+    /** Deletes the cached copy of a list the driver removed. */
+    fun forget(context: Context, list: FilterList) {
+        cacheFile(context, list).delete()
+    }
+
+    fun isAllowlisted(host: String?): Boolean {
+        if (host.isNullOrEmpty()) return false
+        val current = allowlist
+        if (current.isEmpty()) return false
+        val normalized = host.lowercase()
+        return current.any { DomainUtils.hostMatchesDomain(normalized, it) }
+    }
+
+    /**
+     * Decides a single subresource request and, if it should be blocked, builds the response for
+     * it. [pageUrl] is the document the request belongs to, tracked by the WebView client because
+     * a WebView's own url can only be read on the UI thread. Null means let the request through.
+     */
+    fun response(request: WebResourceRequest, pageUrl: String?): WebResourceResponse? {
+        if (!enabled) return null
+        // A ranged request is a video or audio stream fetching its next piece: ads never come
+        // that way, and a stream makes hundreds of them, so they skip the lists entirely.
+        if (request.requestHeaders?.keys?.any { it.equals("Range", ignoreCase = true) } == true) return null
+        val started = System.nanoTime()
+        try {
+            return decide(request, pageUrl)
+        } finally {
+            checkedCount.incrementAndGet()
+            checkedNanos.addAndGet(System.nanoTime() - started)
+        }
+    }
+
+    /** Logs what the blocker cost the page that just finished loading, and starts counting afresh. */
+    fun logPageCost(url: String?) {
+        val count = checkedCount.getAndSet(0)
+        val ms = checkedNanos.getAndSet(0) / 1_000_000
+        val blocked = blockedSincePage.getAndSet(0)
+        if (count > 0) GearslipLog.i("adblock: $count requests checked in ${ms}ms, $blocked blocked, for ${url?.substringBefore('?')}")
+    }
+
+    private fun decide(request: WebResourceRequest, pageUrl: String?): WebResourceResponse? {
+        val current = engine ?: return null
+
+        // Never interfere with top-level navigation: a mistake there costs the whole page.
+        if (request.isForMainFrame) return null
+
+        val url = request.url ?: return null
+        val scheme = url.scheme?.lowercase()
+        if (scheme != "http" && scheme != "https") return null
+
+        val documentHost = pageUrl?.let { runCatching { android.net.Uri.parse(it).host }.getOrNull() }
+        if (isAllowlisted(documentHost)) return null
+
+        val requestHost = url.host?.lowercase()
+        val type = ResourceType.infer(request)
+        val isThirdParty = DomainUtils.isThirdParty(requestHost, documentHost)
+
+        val match = runCatching {
+            current.matchBlockingRule(url.toString(), requestHost, documentHost, type, isThirdParty)
+        }.getOrNull() ?: return null
+
+        blockedCount.incrementAndGet()
+        blockedSincePage.incrementAndGet()
+        return blockedResponse(request, match.redirectResource)
+    }
+
+    /**
+     * The stand-in served for a blocked request.
+     *
+     * The content type matters as much as the emptiness. A page that asked for a script and
+     * receives `text/plain` does not get a script that does nothing — it gets a resource the
+     * browser refuses to execute, and any code waiting on that script waits until it times
+     * out. YouTube's player does exactly this with its ad-status check, which showed up as a
+     * five to ten second stall before playback. So each blocked request is answered with a
+     * valid, empty thing of the kind it asked for, which is what uBlock Origin's `noop`
+     * redirect resources do.
+     *
+     * When the matched rule named a specific `$redirect=` resource we recognise, that exact
+     * stub is served instead of the generic empty one -- see [RedirectResources] for why that
+     * sometimes matters.
+     */
+    private fun blockedResponse(request: WebResourceRequest, redirectResource: String?): WebResourceResponse {
+        val headers = mapOf(
+            "Access-Control-Allow-Origin" to "*",
+            "Cache-Control" to "no-store"
+        )
+
+        if (redirectResource != null) {
+            RedirectResources.response(redirectResource, headers)?.let { return it }
+        }
+
+        fun response(mimeType: String, encoding: String?, body: ByteArray) =
+            WebResourceResponse(mimeType, encoding, 200, "OK", headers, ByteArrayInputStream(body))
+
+        return when (ResourceType.infer(request)) {
+            ResourceType.IMAGE -> response("image/gif", null, transparentGifBytes)
+            ResourceType.SCRIPT -> response("application/javascript", "utf-8", EMPTY)
+            ResourceType.STYLESHEET -> response("text/css", "utf-8", EMPTY)
+            ResourceType.SUBDOCUMENT, ResourceType.DOCUMENT -> response("text/html", "utf-8", EMPTY)
+            // Callers parse this; an empty body would throw where "{}" quietly yields nothing.
+            ResourceType.XHR -> response("application/json", "utf-8", EMPTY_JSON)
+            ResourceType.MEDIA -> response("video/mp4", null, EMPTY)
+            ResourceType.FONT -> response("font/woff2", null, EMPTY)
+            else -> response("text/plain", "utf-8", EMPTY)
+        }
+    }
+
+    /** CSS injected at document start, or an empty string when nothing applies. */
+    fun cssForHost(host: String?): String {
+        if (!enabled) return ""
+        if (isAllowlisted(host)) return ""
+        return engine?.cssForHost(host).orEmpty()
+    }
+
+    /** Whether the YouTube-specific ad-stripping scripts should run for [host]. */
+    fun isYouTubeBlockingEnabled(host: String?): Boolean {
+        if (!enabled || !youTubeEnabled) return false
+        return !isAllowlisted(host)
+    }
+
+    /**
+     * Whether non-ad cosmetic site tweaks (hiding a redundant footer nav, a Shorts shelf, ...)
+     * should run. Independent of ad blocking: a user may want one without the other, and unlike
+     * ad blocking there is no per-host allowlist for it, since it isn't blocking anything.
+     */
+    fun isCustomSiteTweaksEnabled(): Boolean = false
+
+    /** Whether a page's own fixed bottom bar should be hidden, per the in-drawer toggle. */
+    fun isHideSiteFootersEnabled(): Boolean = false
+
+    /** CSS for generic rules whose class or id turned up in the page's DOM. */
+    fun cssForTokens(host: String?, classNames: String, ids: String): String {
+        if (!enabled) return ""
+        if (isAllowlisted(host)) return ""
+        return engine?.cssForTokens(host, classNames, ids).orEmpty()
+    }
+
+    /**
+     * The `:has-text()` rules for [host], as a JSON array of `[selector, regexSource]` pairs, for
+     * the page's own JavaScript to apply -- there is no CSS equivalent for a text match, unlike
+     * every other cosmetic rule this engine serves.
+     */
+    fun hasTextRulesForHost(host: String?): String {
+        if (!enabled) return "[]"
+        if (isAllowlisted(host)) return "[]"
+        val rules = engine?.hasTextRulesForHost(host) ?: return "[]"
+        if (rules.isEmpty()) return "[]"
+
+        val array = org.json.JSONArray()
+        for ((selector, pattern) in rules) {
+            array.put(org.json.JSONArray().put(selector).put(pattern))
+        }
+        return array.toString()
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/adblock/AdBlockTypes.kt

@@ -0,0 +1,170 @@
+package app.seb3thehacker.gearslip.browser.adblock
+
+import android.webkit.WebResourceRequest
+
+/**
+ * Resource types used by filter list options ($script, $image, ...).
+ *
+ * WebResourceRequest does not expose the resource type directly, so [infer] reconstructs it
+ * from the Sec-Fetch-Dest request header where WebView sends one, falling back to the file
+ * extension and then the Accept header.
+ */
+internal object ResourceType {
+    const val NONE = 0
+    const val DOCUMENT = 1 shl 0
+    const val SUBDOCUMENT = 1 shl 1
+    const val SCRIPT = 1 shl 2
+    const val IMAGE = 1 shl 3
+    const val STYLESHEET = 1 shl 4
+    const val XHR = 1 shl 5
+    const val FONT = 1 shl 6
+    const val MEDIA = 1 shl 7
+    const val WEBSOCKET = 1 shl 8
+    const val PING = 1 shl 9
+    const val OBJECT = 1 shl 10
+    const val OTHER = 1 shl 11
+
+    fun fromOptionName(name: String): Int = when (name) {
+        "document" -> DOCUMENT
+        "subdocument", "frame" -> SUBDOCUMENT
+        "script" -> SCRIPT
+        "image" -> IMAGE
+        "stylesheet", "css" -> STYLESHEET
+        "xmlhttprequest", "xhr" -> XHR
+        "font" -> FONT
+        "media" -> MEDIA
+        "websocket" -> WEBSOCKET
+        "ping", "beacon" -> PING
+        "object", "object-subrequest" -> OBJECT
+        "other" -> OTHER
+        else -> NONE
+    }
+
+    fun infer(request: WebResourceRequest): Int {
+        if (request.isForMainFrame) return DOCUMENT
+
+        val headers = request.requestHeaders
+        val dest = headers?.entries
+            ?.firstOrNull { it.key.equals("Sec-Fetch-Dest", ignoreCase = true) }
+            ?.value
+            ?.lowercase()
+
+        if (!dest.isNullOrEmpty() && dest != "empty") {
+            val fromDest = when (dest) {
+                "document" -> DOCUMENT
+                "iframe", "frame", "embed" -> SUBDOCUMENT
+                "script", "worker", "sharedworker", "serviceworker" -> SCRIPT
+                "image" -> IMAGE
+                "style" -> STYLESHEET
+                "font" -> FONT
+                "audio", "video", "track", "audioworklet" -> MEDIA
+                "object" -> OBJECT
+                "report" -> PING
+                "manifest" -> OTHER
+                else -> NONE
+            }
+            if (fromDest != NONE) return fromDest
+        }
+
+        val fromExtension = extensionType(request.url?.path)
+        if (fromExtension != NONE) return fromExtension
+
+        val accept = headers?.entries
+            ?.firstOrNull { it.key.equals("Accept", ignoreCase = true) }
+            ?.value
+            ?.lowercase()
+        if (accept != null) {
+            when {
+                accept.startsWith("image/") || accept.contains("image/avif") -> return IMAGE
+                accept.startsWith("text/css") -> return STYLESHEET
+                accept.startsWith("video/") || accept.startsWith("audio/") -> return MEDIA
+                accept.contains("application/javascript") -> return SCRIPT
+            }
+        }
+
+        // "empty" is what fetch()/XMLHttpRequest report, and is also the fallback when
+        // WebView sends no Sec-Fetch-Dest at all.
+        return if (dest == "empty") XHR else OTHER
+    }
+
+    private fun extensionType(path: String?): Int {
+        if (path.isNullOrEmpty()) return NONE
+        val dot = path.lastIndexOf('.')
+        if (dot < 0 || dot == path.length - 1) return NONE
+        return when (path.substring(dot + 1).lowercase()) {
+            "js", "mjs" -> SCRIPT
+            "css" -> STYLESHEET
+            "png", "jpg", "jpeg", "gif", "webp", "svg", "ico", "bmp", "avif" -> IMAGE
+            "woff", "woff2", "ttf", "otf", "eot" -> FONT
+            "mp4", "webm", "ogg", "mp3", "m4a", "m4s", "ts", "m3u8", "mpd" -> MEDIA
+            "json" -> XHR
+            "swf" -> OBJECT
+            else -> NONE
+        }
+    }
+}
+
+/** Helpers for comparing hosts without pulling in a full public suffix list. */
+internal object DomainUtils {
+    /**
+     * Common multi-label public suffixes. This is deliberately a short list rather than the
+     * full PSL: it is only used to decide first-party vs third-party, where being wrong means
+     * a $third-party rule misfires on an uncommon TLD, not a broken page.
+     */
+    private val MULTI_LABEL_SUFFIXES = hashSetOf(
+        "co.uk", "org.uk", "me.uk", "ac.uk", "gov.uk", "net.uk", "sch.uk",
+        "co.jp", "ne.jp", "or.jp", "ac.jp", "go.jp",
+        "com.au", "net.au", "org.au", "edu.au", "gov.au",
+        "co.nz", "net.nz", "org.nz",
+        "com.br", "net.br", "org.br",
+        "co.in", "net.in", "org.in",
+        "com.cn", "net.cn", "org.cn",
+        "co.kr", "or.kr",
+        "com.mx", "com.ar", "com.tr", "com.tw", "com.hk", "com.sg", "com.my",
+        "co.za", "com.pl", "com.ua", "co.il", "com.vn", "com.ph", "co.id",
+        "com.es", "com.pt", "com.gr", "com.ro", "com.ru", "org.ru", "net.ru"
+    )
+
+    fun registrableDomain(host: String?): String? {
+        if (host.isNullOrEmpty()) return null
+        val normalized = host.trimEnd('.').lowercase()
+        if (normalized.isEmpty()) return null
+        if (normalized.indexOf(':') >= 0) return normalized
+
+        val labels = normalized.split('.')
+        if (labels.size <= 2) return normalized
+        if (labels.all { label -> label.isNotEmpty() && label.all { it in '0'..'9' } }) return normalized
+
+        val lastTwo = labels[labels.size - 2] + "." + labels[labels.size - 1]
+        if (lastTwo in MULTI_LABEL_SUFFIXES && labels.size >= 3) {
+            return labels[labels.size - 3] + "." + lastTwo
+        }
+        return lastTwo
+    }
+
+    fun isThirdParty(requestHost: String?, documentHost: String?): Boolean {
+        if (requestHost.isNullOrEmpty() || documentHost.isNullOrEmpty()) return false
+        val request = registrableDomain(requestHost) ?: return false
+        val document = registrableDomain(documentHost) ?: return false
+        return !request.equals(document, ignoreCase = true)
+    }
+
+    /** True when [host] is [domain] itself or a subdomain of it. */
+    fun hostMatchesDomain(host: String, domain: String): Boolean {
+        if (host == domain) return true
+        return host.length > domain.length &&
+            host.endsWith(domain) &&
+            host[host.length - domain.length - 1] == '.'
+    }
+
+    /** Emits `a.b.example.com`, `b.example.com`, `example.com`, `com`. */
+    inline fun forEachHostSuffix(host: String, action: (String) -> Unit) {
+        var index = 0
+        while (true) {
+            action(if (index == 0) host else host.substring(index))
+            val dot = host.indexOf('.', index)
+            if (dot < 0) return
+            index = dot + 1
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/adblock/CosmeticFilterBridge.kt

@@ -0,0 +1,336 @@
+package app.seb3thehacker.gearslip.browser.adblock
+
+import android.content.Context
+import android.webkit.JavascriptInterface
+import android.webkit.WebView
+import androidx.webkit.WebViewCompat
+import androidx.webkit.WebViewFeature
+
+/**
+ * Applies element-hiding rules to a page.
+ *
+ * Which rules apply depends on the page's hostname and on what is actually in its DOM, neither
+ * of which is known until the document starts loading, so the page fetches its own stylesheet
+ * through a JavaScript bridge. The bridge exposes two pure functions that return CSS: they read
+ * no page state and perform no action, so handing them to untrusted page content costs nothing.
+ *
+ * Hiding happens in two passes. At document start the page gets the rules written for its own
+ * host, which must land before anything renders — injecting on page finish would let ads appear
+ * and then vanish, which is worse than not hiding them. The generic rules follow once the DOM
+ * exists, keyed on the classes and ids actually present, because shipping all of them up front
+ * would mean roughly 400 KB of CSS per page.
+ */
+object CosmeticFilterBridge {
+
+    const val BRIDGE_OBJECT_NAME = "GearslipContentBlocker"
+
+    /** Stop watching for new elements after this long, to spare the CPU on a head unit. */
+    private const val OBSERVE_DURATION_MS = 30000
+
+    /** Upper bound on how many new class/id names are sent to the bridge in one pass. */
+    private const val MAX_TOKENS_PER_PASS = 4000
+
+    /** True when document-start injection is unavailable and the client must inject later. */
+    val needsPageStartFallback: Boolean
+        get() = !WebViewFeature.isFeatureSupported(WebViewFeature.DOCUMENT_START_SCRIPT)
+
+    val INJECTION_JS: String = """
+        (function () {
+          try {
+            if (window.__gearslipCosmetic) { return; }
+            var bridge = window.$BRIDGE_OBJECT_NAME;
+            if (!bridge || typeof bridge.cssForHost !== 'function') { return; }
+
+            var host = location.hostname;
+            var seenClass = Object.create(null);
+            var seenId = Object.create(null);
+            window.__gearslipCosmetic = true;
+
+            function addStyle(css) {
+              if (!css) { return; }
+              var style = document.createElement('style');
+              style.setAttribute('data-gearslip', 'content-blocker');
+              style.textContent = css;
+              var root = document.head || document.documentElement;
+              if (root) { root.appendChild(style); }
+            }
+
+            // The engine loads from disk in the background and may not be ready when the
+            // first page starts. Keep asking until it answers, so a page that loses the race
+            // still gets its hiding rules rather than none at all.
+            var hostCssApplied = false;
+            function applyHostCss() {
+              if (hostCssApplied) { return true; }
+              var css = bridge.cssForHost(host);
+              if (!css) { return false; }
+              hostCssApplied = true;
+              addStyle(css);
+              return true;
+            }
+            applyHostCss();
+            var retries = [250, 750, 1500, 3000, 5000, 8000, 12000];
+            for (var r = 0; r < retries.length; r++) {
+              setTimeout(function () {
+                try {
+                  if (!hostCssApplied && applyHostCss()) { collect(); }
+                } catch (e) {}
+              }, retries[r]);
+            }
+
+            var classes = [];
+            var ids = [];
+
+            function scan(root, budget) {
+              if (!root || root.nodeType !== 1) { return budget; }
+              var elements = root.getElementsByTagName('*');
+              var total = elements.length + 1;
+              for (var i = 0; i < total && budget > 0; i++) {
+                var element = (i === 0) ? root : elements[i - 1];
+                var id = element.id;
+                if (id && !seenId[id]) { seenId[id] = true; ids.push(id); budget--; }
+                // SVG elements expose className as an SVGAnimatedString, not a string.
+                var names = element.className;
+                if (names && typeof names === 'string') {
+                  var parts = names.split(/\s+/);
+                  for (var j = 0; j < parts.length && budget > 0; j++) {
+                    var name = parts[j];
+                    if (name && !seenClass[name]) {
+                      seenClass[name] = true;
+                      classes.push(name);
+                      budget--;
+                    }
+                  }
+                }
+              }
+              return budget;
+            }
+
+            function collect() {
+              classes.length = 0;
+              ids.length = 0;
+              var budget = $MAX_TOKENS_PER_PASS;
+              if (!scannedOnce) {
+                scannedOnce = true;
+                budget = scan(document.documentElement, budget);
+              } else {
+                // Only look at what the page actually added. Re-walking the whole document
+                // on every mutation costs far more than it finds: on a large single-page app
+                // it means a full DOM traversal every 50ms while the page is starting up.
+                for (var i = 0; i < pending.length && budget > 0; i++) {
+                  budget = scan(pending[i], budget);
+                }
+              }
+              pending.length = 0;
+              if (classes.length || ids.length) {
+                addStyle(bridge.cssForTokens(host, classes.join(' '), ids.join(' ')));
+              }
+            }
+
+            var scannedOnce = false;
+            var pending = [];
+            var scheduled = false;
+            function schedule() {
+              if (scheduled) { return; }
+              scheduled = true;
+              setTimeout(function () {
+                scheduled = false;
+                try { collect(); } catch (e) {}
+              }, 50);
+            }
+
+            if (document.readyState === 'loading') {
+              document.addEventListener('DOMContentLoaded', schedule);
+            } else {
+              schedule();
+            }
+
+            if (typeof MutationObserver === 'function' && document.documentElement) {
+              var observer = new MutationObserver(function (records) {
+                for (var i = 0; i < records.length; i++) {
+                  var added = records[i].addedNodes;
+                  for (var j = 0; j < added.length; j++) {
+                    if (added[j].nodeType === 1) { pending.push(added[j]); }
+                  }
+                }
+                // A burst larger than this is a page rebuilding itself; the tail is enough.
+                if (pending.length > 300) { pending.splice(0, pending.length - 300); }
+                if (pending.length) { schedule(); }
+              });
+              observer.observe(document.documentElement, { childList: true, subtree: true });
+              setTimeout(function () {
+                try { observer.disconnect(); } catch (e) {}
+              }, $OBSERVE_DURATION_MS);
+            }
+          } catch (e) {}
+        })();
+        (function () {
+          // Hides a site's own fixed bottom nav bar, which duplicates navigation the app
+          // already provides and costs a sixth of the screen on a ~480px-tall car display.
+          // Found by measuring rather than by a list of known selectors, so it works on any
+          // site. Toggled from the drawer.
+          //
+          // Hiding rather than repositioning is deliberate: an earlier version moved these
+          // bars instead, which fought sites that animate the bar's own position (Twitch
+          // slides its nav bar on scroll) and left it stranded mid-page. display:none has
+          // nothing to fight.
+          try {
+            if (window.__gearslipFooterHiding) { return; }
+            window.__gearslipFooterHiding = true;
+            var bridge = window.$BRIDGE_OBJECT_NAME;
+            if (!bridge || typeof bridge.hideSiteFootersEnabled !== 'function') { return; }
+            if (!bridge.hideSiteFootersEnabled()) { return; }
+
+            var MAX_BAR_HEIGHT = 140;
+
+            function hideBottomBars(root, depth) {
+              if (!root || depth < 0 || !root.children) { return; }
+              for (var i = 0; i < root.children.length; i++) {
+                var el = root.children[i];
+                if (el.__gearslipFooterHidden) { continue; }
+                var cs;
+                try { cs = getComputedStyle(el); } catch (e) { continue; }
+                if (cs.display === 'none') { continue; }
+                if (cs.position === 'fixed' || cs.position === 'sticky') {
+                  var rect;
+                  try { rect = el.getBoundingClientRect(); } catch (e) { rect = null; }
+                  if (rect && rect.width >= window.innerWidth * 0.6 &&
+                      rect.height > 0 && rect.height <= MAX_BAR_HEIGHT &&
+                      Math.abs(window.innerHeight - rect.bottom) < 6) {
+                    el.__gearslipFooterHidden = true;
+                    el.style.setProperty('display', 'none', 'important');
+                    continue;
+                  }
+                }
+                hideBottomBars(el, depth - 1);
+              }
+            }
+
+            function run() {
+              try {
+                hideBottomBars(document.body, 3);
+              } catch (e) {}
+            }
+
+            if (document.readyState === 'loading') {
+              document.addEventListener('DOMContentLoaded', run);
+            } else {
+              run();
+            }
+            // Single-page apps mount their nav bar well after first paint, and swap it out
+            // again on navigation, so one pass at load isn't enough.
+            var passes = 0;
+            var timer = setInterval(function () {
+              run();
+              if (++passes > 40) { clearInterval(timer); }
+            }, 500);
+          } catch (e) {}
+        })();
+        (function () {
+          // ":has-text(pattern)" cosmetic rules: hides elements matching a base selector whose
+          // own text also matches a pattern. There is no CSS equivalent for the text half, so
+          // this runs the check in JavaScript instead of the plain <style> the rest of the
+          // cosmetic filters use.
+          try {
+            if (window.__gearslipHasText) { return; }
+            var bridge = window.$BRIDGE_OBJECT_NAME;
+            if (!bridge || typeof bridge.hasTextRulesForHost !== 'function') { return; }
+
+            var rules;
+            try {
+              rules = JSON.parse(bridge.hasTextRulesForHost(location.hostname) || '[]');
+            } catch (e) {
+              rules = [];
+            }
+            if (!rules.length) { return; }
+            window.__gearslipHasText = true;
+
+            var compiled = [];
+            for (var i = 0; i < rules.length; i++) {
+              try {
+                compiled.push({ selector: rules[i][0], regex: new RegExp(rules[i][1], 'i') });
+              } catch (e) {}
+            }
+            if (!compiled.length) { return; }
+
+            function run() {
+              for (var i = 0; i < compiled.length; i++) {
+                var rule = compiled[i];
+                var elements;
+                try { elements = document.querySelectorAll(rule.selector); } catch (e) { continue; }
+                for (var j = 0; j < elements.length; j++) {
+                  var el = elements[j];
+                  if (el.__gearslipHasTextHidden) { continue; }
+                  var text = el.textContent;
+                  if (text && rule.regex.test(text)) {
+                    el.__gearslipHasTextHidden = true;
+                    el.style.setProperty('display', 'none', 'important');
+                  }
+                }
+              }
+            }
+
+            if (document.readyState === 'loading') {
+              document.addEventListener('DOMContentLoaded', run);
+            } else {
+              run();
+            }
+            // Matches uBlock Origin's own behaviour for this rule type: it re-evaluates on a
+            // timer rather than per-mutation, since a text match can only be judged once an
+            // element's subtree has actually finished changing.
+            var passes = 0;
+            var timer = setInterval(function () {
+              run();
+              if (++passes > 40) { clearInterval(timer); }
+            }, 500);
+          } catch (e) {}
+        })();
+    """.trimIndent()
+
+    fun attach(webView: WebView) {
+        webView.addJavascriptInterface(Bridge(webView.context.applicationContext), BRIDGE_OBJECT_NAME)
+        if (!needsPageStartFallback) {
+            runCatching {
+                WebViewCompat.addDocumentStartJavaScript(webView, INJECTION_JS, setOf("*"))
+            }
+            runCatching {
+                WebViewCompat.addDocumentStartJavaScript(
+                    webView,
+                    YouTubeAdBlock.INJECTION_JS,
+                    setOf("*")
+                )
+            }
+        }
+    }
+
+    class Bridge(private val context: Context) {
+        @JavascriptInterface
+        fun cssForHost(host: String?): String = runCatching {
+            AdBlockManager.cssForHost(host)
+        }.getOrDefault("")
+
+        @JavascriptInterface
+        fun youtubeBlockingEnabled(host: String?): Boolean = runCatching {
+            AdBlockManager.isYouTubeBlockingEnabled(host)
+        }.getOrDefault(false)
+
+        @JavascriptInterface
+        fun customSiteTweaksEnabled(): Boolean = runCatching {
+            AdBlockManager.isCustomSiteTweaksEnabled()
+        }.getOrDefault(false)
+
+        @JavascriptInterface
+        fun hideSiteFootersEnabled(): Boolean = runCatching {
+            AdBlockManager.isHideSiteFootersEnabled()
+        }.getOrDefault(false)
+
+        @JavascriptInterface
+        fun hasTextRulesForHost(host: String?): String = runCatching {
+            AdBlockManager.hasTextRulesForHost(host)
+        }.getOrDefault("[]")
+
+        @JavascriptInterface
+        fun cssForTokens(host: String?, classNames: String?, ids: String?): String = runCatching {
+            AdBlockManager.cssForTokens(host, classNames.orEmpty(), ids.orEmpty())
+        }.getOrDefault("")
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/adblock/FilterEngine.kt

@@ -0,0 +1,610 @@
+package app.seb3thehacker.gearslip.browser.adblock
+
+import android.util.LruCache
+
+/**
+ * An immutable, queryable index over a set of parsed filter rules.
+ *
+ * Network rules are bucketed so that a request only ever tests a handful of them:
+ *  - `||host^` rules are indexed by host and found by walking the request host's suffixes;
+ *  - every other rule is indexed under one literal token from its pattern, and a request only
+ *    tests rules whose token appears in the URL;
+ *  - the few rules with no usable token are tested on every request.
+ *
+ * Element-hiding rules are split the same way. Nearly all generic hiding rules are anchored on
+ * a single class or id (`.ad-banner`, `#sponsored`), so they are indexed by that name and only
+ * handed to a page once that class or id actually appears in its DOM. Injecting all of them
+ * unconditionally would mean roughly 400 KB of CSS on every page load.
+ */
+internal class FilterEngine private constructor(
+    private val blockRules: RuleSet,
+    private val allowRules: RuleSet,
+    private val genericComplexSelectors: List<String>,
+    private val genericByClass: HashMap<String, MutableList<String>>,
+    private val genericById: HashMap<String, MutableList<String>>,
+    private val specificSelectors: HashMap<String, MutableList<String>>,
+    private val cosmeticExceptions: HashMap<String, MutableList<String>>,
+    private val genericHasText: List<Pair<String, String>>,
+    private val specificHasText: HashMap<String, MutableList<Pair<String, String>>>,
+    val networkRuleCount: Int,
+    val cosmeticRuleCount: Int
+) {
+
+    private val hostCssCache = LruCache<String, String>(32)
+
+    /** True when the request should be blocked at all, regardless of which rule matched. */
+    fun shouldBlock(
+        url: String,
+        requestHost: String?,
+        documentHost: String?,
+        type: Int,
+        isThirdParty: Boolean
+    ): Boolean = matchBlockingRule(url, requestHost, documentHost, type, isThirdParty) != null
+
+    /**
+     * The block match for this request, or null when it is not blocked. Split out from
+     * [shouldBlock] so the caller can also read the matched rule's `$redirect=` resource name
+     * without a second, separate walk over the same rule sets. A plain `||host^` match (the
+     * common case) carries no [NetworkRule] object at all, hence [BlockMatch] rather than
+     * returning the rule directly.
+     */
+    fun matchBlockingRule(
+        url: String,
+        requestHost: String?,
+        documentHost: String?,
+        type: Int,
+        isThirdParty: Boolean
+    ): BlockMatch? {
+        val lowerUrl = url.lowercase()
+        val hostStart = hostStart(lowerUrl)
+        val hostEnd = hostEnd(lowerUrl, hostStart)
+        val tokens = ArrayList<String>(16)
+        tokenize(lowerUrl, tokens)
+
+        val blockingMatch = matchingRule(blockRules, lowerUrl, hostStart, hostEnd, requestHost, documentHost, type, isThirdParty, tokens)
+            ?: return null
+        if (matchesAny(allowRules, lowerUrl, hostStart, hostEnd, requestHost, documentHost, type, isThirdParty, tokens)) {
+            return null
+        }
+        return blockingMatch
+    }
+
+    class BlockMatch(val redirectResource: String?) {
+        companion object {
+            val PLAIN = BlockMatch(null)
+        }
+    }
+
+    /**
+     * The stylesheet injected at document start: rules written for this site, plus the handful
+     * of generic rules that are not anchored on a class or id.
+     */
+    fun cssForHost(host: String?): String {
+        val normalized = host?.lowercase().orEmpty()
+        hostCssCache.get(normalized)?.let { return it }
+
+        val exceptions = exceptionsFor(normalized)
+        val selectors = ArrayList<String>(genericComplexSelectors.size + 32)
+        if (normalized.isNotEmpty()) {
+            DomainUtils.forEachHostSuffix(normalized) { suffix ->
+                specificSelectors[suffix]?.let { selectors.addAll(it) }
+            }
+        }
+        selectors.addAll(genericComplexSelectors)
+
+        val css = buildHidingCss(selectors, exceptions)
+        hostCssCache.put(normalized, css)
+        return css
+    }
+
+    private val hasTextCache = LruCache<String, List<Pair<String, String>>>(32)
+
+    /**
+     * The `:has-text()` rules (base selector, JS regex source) that apply to [host]. Delivered
+     * separately from [cssForHost] because there is no CSS equivalent for a text match -- the
+     * caller runs these with JavaScript instead of a `<style>` element.
+     */
+    fun hasTextRulesForHost(host: String?): List<Pair<String, String>> {
+        val normalized = host?.lowercase().orEmpty()
+        hasTextCache.get(normalized)?.let { return it }
+
+        val rules = ArrayList<Pair<String, String>>(genericHasText.size + 4)
+        if (normalized.isNotEmpty()) {
+            DomainUtils.forEachHostSuffix(normalized) { suffix ->
+                specificHasText[suffix]?.let { rules.addAll(it) }
+            }
+        }
+        rules.addAll(genericHasText)
+
+        hasTextCache.put(normalized, rules)
+        return rules
+    }
+
+    /**
+     * The stylesheet for generic rules whose class or id has turned up in the page. [classNames]
+     * and [ids] are whitespace-separated, as collected from the live DOM.
+     */
+    fun cssForTokens(host: String?, classNames: String, ids: String): String {
+        val normalized = host?.lowercase().orEmpty()
+        val exceptions = exceptionsFor(normalized)
+        val selectors = ArrayList<String>()
+
+        collectByToken(classNames, genericByClass, selectors)
+        collectByToken(ids, genericById, selectors)
+        if (selectors.isEmpty()) return ""
+
+        return buildHidingCss(selectors, exceptions)
+    }
+
+    private fun collectByToken(
+        tokens: String,
+        index: HashMap<String, MutableList<String>>,
+        out: MutableList<String>
+    ) {
+        if (tokens.isEmpty() || index.isEmpty()) return
+        var start = 0
+        val length = tokens.length
+        while (start < length) {
+            while (start < length && tokens[start].isWhitespace()) start++
+            if (start >= length) break
+            var end = start
+            while (end < length && !tokens[end].isWhitespace()) end++
+            index[tokens.substring(start, end)]?.let { out.addAll(it) }
+            start = end
+        }
+    }
+
+    private fun exceptionsFor(host: String): Set<String> {
+        if (host.isEmpty() || cosmeticExceptions.isEmpty()) return emptySet()
+        var result: MutableSet<String>? = null
+        DomainUtils.forEachHostSuffix(host) { suffix ->
+            cosmeticExceptions[suffix]?.let { exceptions ->
+                val target = result ?: HashSet<String>().also { result = it }
+                target.addAll(exceptions)
+            }
+        }
+        return result ?: emptySet()
+    }
+
+    private fun buildHidingCss(selectors: List<String>, exceptions: Set<String>): String {
+        val usable = if (exceptions.isEmpty()) {
+            selectors
+        } else {
+            selectors.filterNot { it in exceptions }
+        }
+        if (usable.isEmpty()) return ""
+
+        val builder = StringBuilder(usable.size * 24)
+        // One rule per chunk rather than one rule for everything: a browser drops an entire
+        // rule if any selector in it fails to parse, so a chunk limits that blast radius.
+        for (chunk in usable.chunked(SELECTORS_PER_RULE)) {
+            builder.append(chunk.joinToString(","))
+            builder.append("{display:none!important}")
+        }
+        return builder.toString()
+    }
+
+    private fun matchesAny(
+        ruleSet: RuleSet,
+        url: String,
+        hostStart: Int,
+        hostEnd: Int,
+        requestHost: String?,
+        documentHost: String?,
+        type: Int,
+        isThirdParty: Boolean,
+        tokens: List<String>
+    ): Boolean {
+        if (!requestHost.isNullOrEmpty()) {
+            var found = false
+            DomainUtils.forEachHostSuffix(requestHost) { suffix ->
+                if (!found) {
+                    if (suffix in ruleSet.plainHosts) {
+                        found = true
+                    } else {
+                        val candidates = ruleSet.hostIndex[suffix]
+                        if (candidates != null) {
+                            for (rule in candidates) {
+                                if (optionsMatch(rule, type, isThirdParty, documentHost)) {
+                                    found = true
+                                    break
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+            if (found) return true
+        }
+
+        for (token in tokens) {
+            val candidates = ruleSet.tokenIndex[token] ?: continue
+            for (rule in candidates) {
+                if (optionsMatch(rule, type, isThirdParty, documentHost) &&
+                    matchesUrl(rule, url, hostStart, hostEnd)
+                ) {
+                    return true
+                }
+            }
+        }
+
+        for (rule in ruleSet.catchAll) {
+            if (optionsMatch(rule, type, isThirdParty, documentHost) &&
+                matchesUrl(rule, url, hostStart, hostEnd)
+            ) {
+                return true
+            }
+        }
+        return false
+    }
+
+    /** Same walk as [matchesAny], but returns the match itself instead of a plain boolean. */
+    private fun matchingRule(
+        ruleSet: RuleSet,
+        url: String,
+        hostStart: Int,
+        hostEnd: Int,
+        requestHost: String?,
+        documentHost: String?,
+        type: Int,
+        isThirdParty: Boolean,
+        tokens: List<String>
+    ): BlockMatch? {
+        if (!requestHost.isNullOrEmpty()) {
+            var result: BlockMatch? = null
+            DomainUtils.forEachHostSuffix(requestHost) { suffix ->
+                if (result == null) {
+                    if (suffix in ruleSet.plainHosts) {
+                        result = BlockMatch.PLAIN
+                    } else {
+                        val candidates = ruleSet.hostIndex[suffix]
+                        if (candidates != null) {
+                            for (rule in candidates) {
+                                if (optionsMatch(rule, type, isThirdParty, documentHost)) {
+                                    result = BlockMatch(rule.redirectResource)
+                                    break
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+            if (result != null) return result
+        }
+
+        for (token in tokens) {
+            val candidates = ruleSet.tokenIndex[token] ?: continue
+            for (rule in candidates) {
+                if (optionsMatch(rule, type, isThirdParty, documentHost) &&
+                    matchesUrl(rule, url, hostStart, hostEnd)
+                ) {
+                    return BlockMatch(rule.redirectResource)
+                }
+            }
+        }
+
+        for (rule in ruleSet.catchAll) {
+            if (optionsMatch(rule, type, isThirdParty, documentHost) &&
+                matchesUrl(rule, url, hostStart, hostEnd)
+            ) {
+                return BlockMatch(rule.redirectResource)
+            }
+        }
+        return null
+    }
+
+    private fun optionsMatch(
+        rule: NetworkRule,
+        type: Int,
+        isThirdParty: Boolean,
+        documentHost: String?
+    ): Boolean {
+        if (rule.typeMask != 0 && (rule.typeMask and type) == 0) return false
+        if (rule.excludedTypeMask != 0 && (rule.excludedTypeMask and type) != 0) return false
+
+        val thirdParty = rule.thirdParty
+        if (thirdParty != null && thirdParty != isThirdParty) return false
+
+        val include = rule.includeDomains
+        val exclude = rule.excludeDomains
+        if (include != null || exclude != null) {
+            val host = documentHost ?: return false
+            if (exclude != null && exclude.any { DomainUtils.hostMatchesDomain(host, it) }) return false
+            if (include != null && !include.any { DomainUtils.hostMatchesDomain(host, it) }) return false
+        }
+        return true
+    }
+
+    private fun matchesUrl(rule: NetworkRule, url: String, hostStart: Int, hostEnd: Int): Boolean {
+        if (rule.anchorDomain) {
+            if (matchFrom(url, hostStart, rule)) return true
+            var index = hostStart
+            while (index < hostEnd) {
+                if (url[index] == '.' && matchFrom(url, index + 1, rule)) return true
+                index++
+            }
+            return false
+        }
+        if (rule.anchorStart) return matchFrom(url, 0, rule)
+
+        val first = rule.segments[0]
+        if (first.isNotEmpty() && first.indexOf('^') < 0) {
+            var index = url.indexOf(first)
+            while (index >= 0) {
+                if (matchFrom(url, index, rule)) return true
+                index = url.indexOf(first, index + 1)
+            }
+            return false
+        }
+
+        var index = 0
+        while (index <= url.length) {
+            if (matchFrom(url, index, rule)) return true
+            index++
+        }
+        return false
+    }
+
+    private fun matchFrom(url: String, start: Int, rule: NetworkRule): Boolean {
+        val segments = rule.segments
+        var position = matchSegmentAt(url, start, segments[0])
+        if (position < 0) return false
+
+        for (i in 1 until segments.size) {
+            val segment = segments[i]
+            if (segment.isEmpty()) continue
+            var probe = position
+            var matchedEnd = -1
+            while (probe <= url.length) {
+                val end = matchSegmentAt(url, probe, segment)
+                if (end >= 0) {
+                    matchedEnd = end
+                    break
+                }
+                probe++
+            }
+            if (matchedEnd < 0) return false
+            position = matchedEnd
+        }
+
+        if (rule.anchorEnd && segments[segments.size - 1].isNotEmpty() && position != url.length) {
+            return false
+        }
+        return true
+    }
+
+    /** Returns the index just past the match, or -1. `^` matches one separator or end-of-URL. */
+    private fun matchSegmentAt(url: String, start: Int, segment: String): Int {
+        var position = start
+        for (i in segment.indices) {
+            val expected = segment[i]
+            if (expected == '^') {
+                if (position >= url.length) {
+                    // A separator may stand for the end of the address, but only as the last
+                    // character of the segment.
+                    return if (i == segment.length - 1) position else -1
+                }
+                if (!isSeparator(url[position])) return -1
+                position++
+            } else {
+                if (position >= url.length || url[position] != expected) return -1
+                position++
+            }
+        }
+        return position
+    }
+
+    companion object {
+        private const val MIN_TOKEN_LENGTH = 3
+        private const val SELECTORS_PER_RULE = 100
+
+        private fun isSeparator(c: Char): Boolean = when {
+            c in 'a'..'z' -> false
+            c in 'A'..'Z' -> false
+            c in '0'..'9' -> false
+            c == '_' || c == '-' || c == '.' || c == '%' -> false
+            else -> true
+        }
+
+        private fun hostStart(url: String): Int {
+            val scheme = url.indexOf("://")
+            return if (scheme < 0) 0 else scheme + 3
+        }
+
+        private fun hostEnd(url: String, hostStart: Int): Int {
+            var index = hostStart
+            while (index < url.length) {
+                val c = url[index]
+                if (c == '/' || c == '?' || c == '#' || c == ':') return index
+                index++
+            }
+            return url.length
+        }
+
+        private fun tokenize(text: String, out: MutableList<String>) {
+            var index = 0
+            val length = text.length
+            while (index < length) {
+                val c = text[index]
+                if (c.isLetterOrDigit()) {
+                    var end = index + 1
+                    while (end < length && text[end].isLetterOrDigit()) end++
+                    if (end - index >= MIN_TOKEN_LENGTH) out.add(text.substring(index, end))
+                    index = end
+                } else {
+                    index++
+                }
+            }
+        }
+
+        /** The longest literal token in the pattern, used as the rule's index key. */
+        private fun bestToken(rule: NetworkRule): String? {
+            var best: String? = null
+            val tokens = ArrayList<String>(4)
+            for (segment in rule.segments) {
+                tokens.clear()
+                tokenize(segment, tokens)
+                for (token in tokens) {
+                    val current = best
+                    if (current == null || token.length > current.length) best = token
+                }
+            }
+            return best
+        }
+
+        /**
+         * The leading class or id a selector is anchored on, as (`.` or `#`) to name, or null
+         * when the selector does not start with a plain class or id.
+         */
+        private fun anchorToken(selector: String): Pair<Char, String>? {
+            if (selector.length < 2) return null
+            val kind = selector[0]
+            if (kind != '.' && kind != '#') return null
+            var end = 1
+            while (end < selector.length) {
+                val c = selector[end]
+                if (c.isLetterOrDigit() || c == '-' || c == '_') end++ else break
+            }
+            if (end == 1) return null
+            return kind to selector.substring(1, end)
+        }
+
+        fun build(lines: Sequence<String>): FilterEngine {
+            val builder = Builder()
+            for (line in lines) builder.addLine(line)
+            return builder.finish()
+        }
+    }
+
+    /**
+     * Accumulates rules one line at a time, fed straight from a reader so that the whole list
+     * never exists in memory as a collection of lines. Parsing EasyList and EasyPrivacy
+     * together takes roughly 250ms on a Pixel 6 in a release build. Be wary of profiling this
+     * in a debug build: `android:debuggable` disables ART's inlining and made the same work
+     * take over nine seconds, which looks like an algorithmic problem but is not one.
+     */
+    internal class Builder {
+        private val blockRules = RuleSet()
+        private val allowRules = RuleSet()
+        private val genericComplex = LinkedHashSet<String>()
+        // Pre-sized: EasyList and EasyPrivacy together fill these to roughly these counts, and
+        // rehashing a 90k-entry map on the way there is pure waste.
+        private val genericByClass = HashMap<String, MutableList<String>>(16384)
+        private val genericById = HashMap<String, MutableList<String>>(8192)
+        private val specificSelectors = HashMap<String, MutableList<String>>(16384)
+        private val cosmeticExceptions = HashMap<String, MutableList<String>>(1024)
+        private val genericHasText = mutableListOf<Pair<String, String>>()
+        private val specificHasText = HashMap<String, MutableList<Pair<String, String>>>()
+        private var networkRuleCount = 0
+        private var cosmeticRuleCount = 0
+
+        fun addLine(rawLine: String) {
+            if (rawLine.isEmpty()) return
+            // Only pay for trim() on the rare line that actually has surrounding whitespace.
+            val needsTrim = rawLine[0] == ' ' || rawLine[0] == '\t' ||
+                rawLine[rawLine.length - 1] == ' ' || rawLine[rawLine.length - 1] == '\t'
+            val line = if (needsTrim) rawLine.trim() else rawLine
+            if (line.isEmpty()) return
+            if (line[0] == '!' || line[0] == '[') return
+
+            val separator = FilterParser.cosmeticSeparatorIndex(line)
+            if (separator >= 0) {
+                addCosmeticRule(line, separator)
+                return
+            }
+
+            val isException = line.startsWith("@@")
+            val rule = FilterParser.parseNetworkRule(line) ?: return
+            networkRuleCount++
+            val target = if (isException) allowRules else blockRules
+
+            val hostAnchor = rule.hostAnchor
+            if (hostAnchor != null) {
+                if (rule.hasNoOptions) {
+                    target.plainHosts.add(hostAnchor)
+                } else {
+                    target.hostIndex.getOrPut(hostAnchor) { mutableListOf() }.add(rule)
+                }
+                return
+            }
+
+            val token = bestToken(rule)
+            if (token != null) {
+                target.tokenIndex.getOrPut(token) { mutableListOf() }.add(rule)
+            } else {
+                target.catchAll.add(rule)
+            }
+        }
+
+        private fun addCosmeticRule(line: String, separator: Int) {
+            val rule = FilterParser.parseCosmeticRule(line, separator) ?: return
+            cosmeticRuleCount++
+
+            // :has-text() has no CSS equivalent, so it is matched by JavaScript from its own
+            // list instead of joining the CSS selector strings above. Exceptions for it are not
+            // supported -- rare enough in EasyList/EasyPrivacy that dropping them outright (by
+            // not indexing this rule) is a safe simplification rather than a real gap.
+            val textPattern = rule.hasTextPattern
+            if (textPattern != null) {
+                if (rule.isException) return
+                val entry = rule.selector to textPattern
+                if (rule.includeDomains != null) {
+                    rule.includeDomains.forEach { domain ->
+                        specificHasText.getOrPut(domain) { mutableListOf() }.add(entry)
+                    }
+                } else {
+                    genericHasText.add(entry)
+                }
+                return
+            }
+
+            when {
+                rule.isException -> {
+                    rule.includeDomains?.forEach { domain ->
+                        cosmeticExceptions.getOrPut(domain) { mutableListOf() }.add(rule.selector)
+                    }
+                }
+                rule.includeDomains != null -> {
+                    rule.includeDomains.forEach { domain ->
+                        specificSelectors.getOrPut(domain) { mutableListOf() }.add(rule.selector)
+                    }
+                }
+                else -> {
+                    val anchor = anchorToken(rule.selector)
+                    if (anchor == null) {
+                        genericComplex.add(rule.selector)
+                    } else {
+                        val index = if (anchor.first == '.') genericByClass else genericById
+                        index.getOrPut(anchor.second) { mutableListOf() }.add(rule.selector)
+                    }
+                    // `~example.com##.ad` hides everywhere except the excluded domains.
+                    rule.excludeDomains?.forEach { domain ->
+                        cosmeticExceptions.getOrPut(domain) { mutableListOf() }.add(rule.selector)
+                    }
+                }
+            }
+        }
+
+        fun finish(): FilterEngine = FilterEngine(
+            blockRules = blockRules,
+            allowRules = allowRules,
+            genericComplexSelectors = genericComplex.toList(),
+            genericByClass = genericByClass,
+            genericById = genericById,
+            specificSelectors = specificSelectors,
+            cosmeticExceptions = cosmeticExceptions,
+            genericHasText = genericHasText,
+            specificHasText = specificHasText,
+            networkRuleCount = networkRuleCount,
+            cosmeticRuleCount = cosmeticRuleCount
+        )
+    }
+
+    internal class RuleSet {
+        /** Bare `||host^` blocks with no options: matching the host is the whole test. */
+        val plainHosts = HashSet<String>()
+        val hostIndex = HashMap<String, MutableList<NetworkRule>>()
+        val tokenIndex = HashMap<String, MutableList<NetworkRule>>()
+        val catchAll = ArrayList<NetworkRule>()
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/adblock/FilterRules.kt

@@ -0,0 +1,330 @@
+package app.seb3thehacker.gearslip.browser.adblock
+
+/**
+ * A parsed network filter rule (Adblock Plus syntax subset).
+ *
+ * [segments] is the pattern split on `*`; each segment is matched literally except for `^`,
+ * which stands for a single separator character (or the end of the URL).
+ */
+internal class NetworkRule(
+    val segments: Array<String>,
+    val anchorDomain: Boolean,
+    val anchorStart: Boolean,
+    val anchorEnd: Boolean,
+    val typeMask: Int,
+    val excludedTypeMask: Int,
+    val thirdParty: Boolean?,
+    val includeDomains: Array<String>?,
+    val excludeDomains: Array<String>?,
+    /** Set when the whole pattern is a bare `||host^`, which lets the engine index it by host. */
+    val hostAnchor: String?,
+    /** Set for `$redirect=name` / `$redirect-rule=name` rules with a resource we can serve. */
+    val redirectResource: String?
+) {
+    /**
+     * True when the rule carries no options, so matching the host is the whole test. The great
+     * majority of list entries are of this shape and the engine stores them as bare strings.
+     */
+    val hasNoOptions: Boolean
+        get() = typeMask == 0 && excludedTypeMask == 0 && thirdParty == null &&
+            includeDomains == null && excludeDomains == null && redirectResource == null
+}
+
+internal class CosmeticRule(
+    val selector: String,
+    val includeDomains: List<String>?,
+    val excludeDomains: List<String>?,
+    val isException: Boolean,
+    /** Set for a `selector:has-text(pattern)` rule: the text [pattern] to match within
+     *  [selector]'s matches, applied by JavaScript rather than as plain CSS. */
+    val hasTextPattern: String? = null
+)
+
+internal object FilterParser {
+
+    /**
+     * Options that change *how* a request is answered rather than whether it is blocked.
+     * A rule carrying one of these is dropped: honouring only its matching half would block
+     * requests the list author meant to rewrite or merely restrict.
+     */
+    private val UNSUPPORTED_OPTIONS = hashSetOf(
+        "csp", "removeparam", "rewrite", "replace", "empty", "mp4",
+        "inline-script", "inline-font", "genericblock", "generichide", "specifichide", "elemhide",
+        "badfilter", "denyallow", "method", "header", "to", "from", "ipaddress", "permissions",
+        "uritransform", "urlskip", "urltransform", "strict1p", "strict3p", "popup", "popunder",
+        "cname", "webrtc", "stealth", "cookie", "network", "app", "extension", "jsonprune",
+        "hls", "referrerpolicy", "match-case-path"
+    )
+
+    /**
+     * Procedural cosmetic syntax that needs uBlock Origin's own runtime to evaluate. These
+     * selectors cannot be expressed as plain CSS, so the rules are skipped.
+     *
+     * `:has()` is not in this list: modern WebView's Chromium supports it natively as plain CSS,
+     * so those selectors are just passed straight through. `:has-text()` is handled separately in
+     * [parseCosmeticRule] rather than being skipped outright -- the simple, common form (a plain
+     * selector followed by one `:has-text(...)`) is split out and matched by JavaScript instead of
+     * CSS, since there is no CSS equivalent for a text match.
+     */
+    private val PROCEDURAL_MARKERS = arrayOf(
+        // ":has-text(" stays here as a safety net: it's stripped out before this check runs
+        // when it's the simple trailing form [extractHasText] understands, so a leftover
+        // occurrence here means that extraction either wasn't attempted (not a cosmetic rule
+        // that reached it) or failed (nested/combined usage), and the rule should be dropped
+        // rather than shipped as literal, invalid CSS.
+        ":has-text(",
+        ":matches-css", ":matches-media", ":matches-path", ":matches-attr",
+        ":xpath(", ":upward(", ":nth-ancestor(", ":style(", ":remove(", ":remove-attr(",
+        ":remove-class(", ":watch-attr(", ":min-text-length(", ":others(", ":shadow(", ":if(",
+        ":if-not(", ":not(:has"
+    )
+
+    private fun isHostCharacter(c: Char): Boolean =
+        c in 'a'..'z' || c in '0'..'9' || c == '.' || c == '-' || c == '_'
+
+    fun parseNetworkRule(line: String): NetworkRule? {
+        var body = line
+        if (body.startsWith("@@")) body = body.substring(2)
+        if (body.isEmpty()) return null
+
+        var pattern = body
+        var optionText: String? = null
+        val dollar = body.lastIndexOf('$')
+        if (dollar >= 0) {
+            pattern = body.substring(0, dollar)
+            optionText = body.substring(dollar + 1)
+        }
+
+        // Regular-expression rules (/pattern/) are not supported.
+        if (pattern.length > 2 && pattern.startsWith("/") && pattern.endsWith("/")) return null
+        if (pattern.isEmpty()) return null
+
+        var anchorDomain = false
+        var anchorStart = false
+        var anchorEnd = false
+        if (pattern.startsWith("||")) {
+            anchorDomain = true
+            pattern = pattern.substring(2)
+        } else if (pattern.startsWith("|")) {
+            anchorStart = true
+            pattern = pattern.substring(1)
+        }
+        if (pattern.endsWith("|")) {
+            anchorEnd = true
+            pattern = pattern.dropLast(1)
+        }
+        if (pattern.isEmpty()) return null
+        pattern = pattern.lowercase()
+
+        var typeMask = 0
+        var excludedTypeMask = 0
+        var thirdParty: Boolean? = null
+        var includeDomains: MutableList<String>? = null
+        var excludeDomains: MutableList<String>? = null
+        var redirectResource: String? = null
+
+        if (optionText != null) {
+            for (rawOption in optionText.split(',')) {
+                var option = rawOption.trim().lowercase()
+                if (option.isEmpty()) continue
+
+                var negated = false
+                if (option.startsWith("~")) {
+                    negated = true
+                    option = option.substring(1)
+                }
+
+                val equals = option.indexOf('=')
+                val key = if (equals >= 0) option.substring(0, equals) else option
+                val value = if (equals >= 0) option.substring(equals + 1) else null
+
+                if (key.isEmpty()) return null
+                if (key in UNSUPPORTED_OPTIONS) return null
+
+                when (key) {
+                    "domain" -> {
+                        if (value.isNullOrEmpty()) return null
+                        for (entry in value.split('|')) {
+                            val domain = entry.trim()
+                            if (domain.isEmpty()) continue
+                            if (domain.startsWith("~")) {
+                                val excluded = domain.substring(1)
+                                if (excluded.isNotEmpty()) {
+                                    (excludeDomains ?: mutableListOf<String>()
+                                        .also { excludeDomains = it }).add(excluded)
+                                }
+                            } else {
+                                (includeDomains ?: mutableListOf<String>()
+                                    .also { includeDomains = it }).add(domain)
+                            }
+                        }
+                    }
+                    "third-party", "3p" -> thirdParty = !negated
+                    "first-party", "1p" -> thirdParty = negated
+                    // Patterns are lower-cased for matching, so $match-case degrades to
+                    // case-insensitive. It only ever widens the match.
+                    "match-case", "important" -> Unit
+                    "all" -> Unit
+                    // `redirect-rule` only fires when another rule would already block the
+                    // request; treating it the same as `redirect` is a harmless simplification
+                    // since we only reach here once a block decision is otherwise made.
+                    "redirect", "redirect-rule" -> {
+                        // AdGuard's priority suffix (`name:10`) doesn't apply to a single-engine
+                        // blocker with no other redirect rule to rank against.
+                        val name = value?.substringBefore(':')
+                        if (name.isNullOrEmpty()) return null
+                        redirectResource = name
+                    }
+                    else -> {
+                        val bit = ResourceType.fromOptionName(key)
+                        if (bit == ResourceType.NONE) return null
+                        if (negated) excludedTypeMask = excludedTypeMask or bit
+                        else typeMask = typeMask or bit
+                    }
+                }
+            }
+        }
+
+        val segments = splitOnWildcards(pattern)
+        if (segments.isEmpty()) return null
+
+        var hostAnchor: String? = null
+        if (anchorDomain && !anchorEnd && segments.size == 1) {
+            val candidate = if (pattern.endsWith("^")) pattern.dropLast(1) else pattern
+            if (candidate.isNotEmpty() && candidate.all { isHostCharacter(it) }) {
+                hostAnchor = candidate
+            }
+        }
+
+        return NetworkRule(
+            segments = segments,
+            anchorDomain = anchorDomain,
+            anchorStart = anchorStart,
+            anchorEnd = anchorEnd,
+            typeMask = typeMask,
+            excludedTypeMask = excludedTypeMask,
+            thirdParty = thirdParty,
+            includeDomains = includeDomains?.toTypedArray(),
+            excludeDomains = excludeDomains?.toTypedArray(),
+            hostAnchor = hostAnchor,
+            redirectResource = redirectResource
+        )
+    }
+
+    private fun splitOnWildcards(pattern: String): Array<String> {
+        if (pattern.indexOf('*') < 0) return arrayOf(pattern)
+        return pattern.split('*').toTypedArray()
+    }
+
+    /** Returns the index of the cosmetic separator, or -1 when the line is not a cosmetic rule. */
+    fun cosmeticSeparatorIndex(line: String): Int {
+        var search = 0
+        while (true) {
+            val hash = line.indexOf('#', search)
+            if (hash < 0) return -1
+            if (hash + 1 < line.length) {
+                val next = line[hash + 1]
+                if (next == '#') return hash
+                if (next == '@' && hash + 2 < line.length && line[hash + 2] == '#') return hash
+                // #?#, #$#, #$?#, #%# and friends are procedural or scriptlet syntax.
+                if (next == '?' || next == '$' || next == '%') return hash
+            }
+            search = hash + 1
+        }
+    }
+
+    fun parseCosmeticRule(line: String, separatorIndex: Int): CosmeticRule? {
+        val isException: Boolean
+        val selectorStart: Int
+        when {
+            line.startsWith("#@#", separatorIndex) -> {
+                isException = true
+                selectorStart = separatorIndex + 3
+            }
+            line.startsWith("##", separatorIndex) -> {
+                isException = false
+                selectorStart = separatorIndex + 2
+            }
+            // Procedural / scriptlet separators cannot be represented as CSS.
+            else -> return null
+        }
+
+        if (selectorStart >= line.length) return null
+        var selector = line.substring(selectorStart).trim()
+        if (selector.isEmpty()) return null
+        if (selector.startsWith("+js(") || selector.startsWith("script:")) return null
+
+        var hasTextPattern: String? = null
+        val hasTextSplit = extractHasText(selector)
+        if (hasTextSplit != null) {
+            selector = hasTextSplit.first
+            hasTextPattern = hasTextSplit.second
+        }
+
+        val lowerSelector = selector.lowercase()
+        if (PROCEDURAL_MARKERS.any { lowerSelector.contains(it) }) return null
+        // A stray brace would let a selector escape its own rule when concatenated.
+        if (selector.contains('{') || selector.contains('}')) return null
+
+        var includeDomains: MutableList<String>? = null
+        var excludeDomains: MutableList<String>? = null
+        val domainText = line.substring(0, separatorIndex).trim()
+        if (domainText.isNotEmpty()) {
+            for (entry in domainText.split(',')) {
+                val domain = entry.trim().lowercase()
+                if (domain.isEmpty()) continue
+                if (domain.startsWith("~")) {
+                    val excluded = domain.substring(1)
+                    if (excluded.isNotEmpty()) {
+                        (excludeDomains ?: mutableListOf<String>().also { excludeDomains = it })
+                            .add(excluded)
+                    }
+                } else {
+                    (includeDomains ?: mutableListOf<String>().also { includeDomains = it })
+                        .add(domain)
+                }
+            }
+        }
+
+        return CosmeticRule(selector, includeDomains, excludeDomains, isException, hasTextPattern)
+    }
+
+    /**
+     * Splits `selector:has-text(pattern)` into (`selector`, JS regex source). Only the simple,
+     * common form is handled -- one `:has-text(...)` as the very last thing in the selector, with
+     * a non-empty selector before it. Anything else (nested inside `:has()`, combined with other
+     * procedural syntax, an empty base selector matching every element) returns null and the
+     * caller falls back to discarding the rule, same as before this existed.
+     */
+    private fun extractHasText(selector: String): Pair<String, String>? {
+        val markerIndex = selector.indexOf(":has-text(")
+        if (markerIndex <= 0) return null
+
+        val argStart = markerIndex + ":has-text(".length
+        var depth = 1
+        var index = argStart
+        while (index < selector.length && depth > 0) {
+            when (selector[index]) {
+                '(' -> depth++
+                ')' -> depth--
+            }
+            if (depth > 0) index++
+        }
+        // The closing paren must be the last character: a trailing combinator or pseudo after
+        // it means this is a more complex selector than the simple form handled here.
+        if (depth != 0 || index != selector.length - 1) return null
+
+        val base = selector.substring(0, markerIndex).trim()
+        if (base.isEmpty() || base.contains(":has-text(")) return null
+
+        var arg = selector.substring(argStart, index).trim()
+        if (arg.isEmpty()) return null
+
+        val pattern = if (arg.length > 1 && arg.startsWith("/") && arg.lastIndexOf('/') > 0) {
+            arg.substring(1, arg.lastIndexOf('/'))
+        } else {
+            Regex.escape(arg)
+        }
+        return base to pattern
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/adblock/RedirectResources.kt

@@ -0,0 +1,93 @@
+package app.seb3thehacker.gearslip.browser.adblock
+
+import android.webkit.WebResourceResponse
+import java.io.ByteArrayInputStream
+
+/**
+ * A small subset of uBlock Origin's / AdGuard's named `$redirect=` resources.
+ *
+ * Blocking most tracking scripts outright is safe -- the page never had a live reference to
+ * them, so nothing calls into the empty response [AdBlockManager.blockedResponse] already
+ * serves. But a handful of scripts are different: page code assumes the object they define
+ * (`ga`, `dataLayer`, `googletag`, ...) exists and calls it immediately, so an empty response
+ * leaves that call throwing a `ReferenceError` that can break unrelated script on the same page.
+ * These stubs define just enough of that surface to no-op safely, which is what the named
+ * `$redirect=` resource is for in the filter list that requested it.
+ *
+ * Anything not in this map still gets blocked -- just with the generic typed-empty response
+ * instead of an exact stub, same as before this existed.
+ */
+internal object RedirectResources {
+
+    private val EMPTY_JS = "".toByteArray()
+
+    private val GOOGLE_ANALYTICS_GA = """
+        (function(){function g(){}var t=function(){t.c[t.q.push(arguments)-1]=null};
+        t.q=[];t.c=[];window.ga=window.ga||t;window._gaq=window._gaq||{push:g};
+        window.GoogleAnalyticsObject=window.GoogleAnalyticsObject||'ga';})();
+    """.trimIndent().toByteArray()
+
+    private val GOOGLE_ANALYTICS_ANALYTICS = """
+        (function(){function s(){}var g={
+        create:function(){return{get:s,set:s,send:s}},getAll:function(){return[]},
+        getByName:function(){return null},remove:s};
+        window.ga=window.ga||function(){(window.ga.q=window.ga.q||[]).push(arguments)};
+        window.ga.create=g.create;window.ga.getAll=g.getAll;window.ga.getByName=g.getByName;
+        window.ga.remove=g.remove;window.gaplugins={Linker:function(){this.decorate=s;this.autoLink=s}};
+        })();
+    """.trimIndent().toByteArray()
+
+    private val GOOGLETAGMANAGER_GTM = """
+        (function(){window.dataLayer=window.dataLayer||[];
+        window.dataLayer.push=function(){};
+        window.google_tag_manager=window.google_tag_manager||{};})();
+    """.trimIndent().toByteArray()
+
+    private val GOOGLETAGSERVICES_GPT = """
+        (function(){function s(){}function u(){return{addService:function(){return this},
+        setTargeting:s,setCollapseEmptyDiv:s,addEventListener:function(){return this},
+        removeEventListener:s,get:s,set:s,getSlotElementId:function(){return''},
+        getSlotId:function(){return{getDomId:function(){return''}}}}}
+        window.googletag=window.googletag||{};
+        window.googletag.cmd=window.googletag.cmd||{push:function(fn){try{fn()}catch(e){}}};
+        var pubads=u();
+        window.googletag.pubads=function(){return pubads};
+        window.googletag.defineSlot=function(){return u()};
+        window.googletag.defineOutOfPageSlot=function(){return u()};
+        window.googletag.enableServices=s;window.googletag.display=s;
+        window.googletag.apiReady=true;})();
+    """.trimIndent().toByteArray()
+
+    private val NOOP_CSS = "".toByteArray()
+    private val NOOP_HTML = "<!doctype html><html><head></head><body></body></html>".toByteArray()
+    private val NOOP_JSON = "{}".toByteArray()
+
+    private val STUBS: Map<String, Pair<String, ByteArray>> = buildMap {
+        // Names as they appear across uBO's and AdGuard's resources.txt / redirect syntax.
+        for (name in listOf("noopjs", "noop.js", "noop-js")) put(name, "application/javascript" to EMPTY_JS)
+        for (name in listOf("noopcss", "noop.css", "noop-css")) put(name, "text/css" to NOOP_CSS)
+        for (name in listOf("noop.txt", "nooptext")) put(name, "text/plain" to "".toByteArray())
+        for (name in listOf("noop.json", "empty")) put(name, "application/json" to NOOP_JSON)
+        for (name in listOf("noop.html", "click2load.html")) put(name, "text/html" to NOOP_HTML)
+        for (name in listOf("google-analytics_ga.js", "google-analytics.com/ga.js", "ga.js"))
+            put(name, "application/javascript" to GOOGLE_ANALYTICS_GA)
+        for (name in listOf(
+            "google-analytics_analytics.js", "google-analytics.com/analytics.js",
+            "googletagmanager_gtag.js", "googletagmanager-gtag"
+        )) put(name, "application/javascript" to GOOGLE_ANALYTICS_ANALYTICS)
+        for (name in listOf("googletagmanager_gtm.js", "googletagmanager.com/gtm.js", "gtm.js"))
+            put(name, "application/javascript" to GOOGLETAGMANAGER_GTM)
+        for (name in listOf("googletagservices_gpt.js", "googletagservices.com/gpt.js", "gpt.js"))
+            put(name, "application/javascript" to GOOGLETAGSERVICES_GPT)
+        for (name in listOf("1x1.gif", "1x1-transparent.gif", "2x2.png", "3x2.png", "32x32.png"))
+            put(name, "image/gif" to AdBlockManager.transparentGifBytes)
+    }
+
+    /** Null when [name] is not one of the resources we ship a stub for. */
+    fun response(name: String, headers: Map<String, String>): WebResourceResponse? {
+        val stub = STUBS[name.lowercase()] ?: return null
+        val (mimeType, body) = stub
+        val encoding = if (mimeType.startsWith("image/")) null else "utf-8"
+        return WebResourceResponse(mimeType, encoding, 200, "OK", headers, ByteArrayInputStream(body))
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/adblock/YouTubeAdBlock.kt

@@ -0,0 +1,239 @@
+package app.seb3thehacker.gearslip.browser.adblock
+
+/**
+ * YouTube ad blocking, plus the cosmetic cleanup that rides along with it.
+ *
+ * Filter lists cannot touch YouTube's video ads. The ad and the video are delivered by the same
+ * hosts, so there is no request to block and no element to hide: the player decides to show an
+ * ad because its own API response told it to. What can be done is what uBlock Origin's
+ * scriptlets do — edit that response before the player reads it.
+ *
+ * Three hooks, all installed before any page script runs:
+ *  - `ytInitialPlayerResponse`, the JSON embedded in the page for the first video watched;
+ *  - `fetch`, used by the single-page app for every later video;
+ *  - `JSON.parse`, a backstop for whatever path the two above miss.
+ *
+ * Each strips the keys the player uses to schedule ads. A periodic sweep then clicks any skip
+ * button and seeks past anything that still slipped through, which also covers ads stitched
+ * into the stream server-side, where nothing client-side can remove them cleanly. All of this,
+ * plus hiding the ad's own banner/in-feed markup, is gated on "Block YouTube video ads": it's
+ * inherently maintenance-prone (YouTube changes these field and class names when it wants to,
+ * and may respond with an anti-adblock notice), so it needs to be switchable off as a unit
+ * without losing ordinary filter-list blocking.
+ *
+ * The Shorts shelf and filter chip row are a separate concern -- cosmetic preference, not ad
+ * blocking -- so they sit behind their own "Custom site tweaks" setting instead, independent of
+ * whether YouTube ad blocking is on. The floating menu button covering a page's own fixed
+ * bottom bar is handled generically for every site in [CosmeticFilterBridge], not here.
+ */
+object YouTubeAdBlock {
+
+    val INJECTION_JS: String = """
+        (function () {
+          try {
+            var host = location.hostname || '';
+            if (!/(^|\.)(youtube\.com|youtube-nocookie\.com|youtubekids\.com)${'$'}/.test(host)) {
+              return;
+            }
+            var bridge = window.${CosmeticFilterBridge.BRIDGE_OBJECT_NAME};
+            if (!bridge) { return; }
+            var adBlockingOn = typeof bridge.youtubeBlockingEnabled === 'function' &&
+              bridge.youtubeBlockingEnabled(host);
+            var tweaksOn = typeof bridge.customSiteTweaksEnabled === 'function' &&
+              bridge.customSiteTweaksEnabled();
+            if (!adBlockingOn && !tweaksOn) { return; }
+            if (window.__gearslipYouTube) { return; }
+            window.__gearslipYouTube = true;
+
+            var styleRules = '';
+
+            if (adBlockingOn) {
+              // The fields the player consults to schedule ad breaks.
+              var AD_KEYS = [
+                'adPlacements', 'playerAds', 'adSlots', 'adBreakHeartbeatParams'
+              ];
+
+              var stripKeys = function (object) {
+                if (!object || typeof object !== 'object') { return; }
+                for (var i = 0; i < AD_KEYS.length; i++) {
+                  if (AD_KEYS[i] in object) {
+                    try { delete object[AD_KEYS[i]]; } catch (e) {}
+                  }
+                }
+              };
+
+              // Deliberately shallow. A player response is a large object and walking all of
+              // it on every parse would cost more than the ads do.
+              var prune = function (payload) {
+                if (!payload || typeof payload !== 'object') { return payload; }
+                if (Array.isArray(payload)) {
+                  for (var i = 0; i < payload.length && i < 50; i++) { prune(payload[i]); }
+                  return payload;
+                }
+                stripKeys(payload);
+                if (payload.playerResponse) { stripKeys(payload.playerResponse); }
+                if (payload.response) { stripKeys(payload.response); }
+                if (payload.playerData) { stripKeys(payload.playerData); }
+                return payload;
+              };
+
+              // 1. The first video: YouTube assigns this from an inline script in the document.
+              try {
+                var initial;
+                Object.defineProperty(window, 'ytInitialPlayerResponse', {
+                  configurable: true,
+                  get: function () { return initial; },
+                  set: function (value) { initial = prune(value); }
+                });
+              } catch (e) {}
+
+              // 2. Every later video in the single-page app.
+              var originalFetch = window.fetch;
+              if (typeof originalFetch === 'function') {
+                window.fetch = function (input, init) {
+                  var url = '';
+                  try {
+                    url = (typeof input === 'string') ? input : ((input && input.url) || '');
+                  } catch (e) {}
+                  var pending = originalFetch.apply(this, arguments);
+                  // Only the player call carries ad scheduling. /next is the comments and
+                  // related-video payload: large, and re-serialising it buys nothing.
+                  if (url.indexOf('/youtubei/v1/player') < 0) {
+                    return pending;
+                  }
+                  return pending.then(function (response) {
+                    return response.text().then(function (text) {
+                      var body = text;
+                      // Cheap string test first: most responses have nothing to strip, and
+                      // parsing plus re-serialising a player response is not free.
+                      if (text.indexOf('"adPlacements"') >= 0 ||
+                          text.indexOf('"playerAds"') >= 0 ||
+                          text.indexOf('"adSlots"') >= 0) {
+                        try {
+                          var data = JSON.parse(text);
+                          prune(data);
+                          body = JSON.stringify(data);
+                        } catch (e) {
+                          body = text;
+                        }
+                      }
+                      // Content-Length describes the original bytes, and Content-Encoding a
+                      // compression this body no longer has. Copying either onto the edited
+                      // body leaves the player waiting on bytes that never arrive.
+                      var headers;
+                      try {
+                        headers = new Headers(response.headers);
+                        headers.delete('content-length');
+                        headers.delete('content-encoding');
+                      } catch (e) {
+                        headers = undefined;
+                      }
+                      return new Response(body, {
+                        status: response.status,
+                        statusText: response.statusText,
+                        headers: headers
+                      });
+                    }).catch(function () { return response; });
+                  });
+                };
+              }
+
+              // 3. Backstop for any path the first two miss.
+              var originalParse = JSON.parse;
+              JSON.parse = function (text, reviver) {
+                var result = originalParse.apply(this, arguments);
+                try { prune(result); } catch (e) {}
+                return result;
+              };
+
+              // Hide the banner, overlay and in-feed ads, which are ordinary elements. The
+              // :has() rules collapse the wrapping feed section too, instead of leaving an
+              // empty gap where the ad used to be.
+              styleRules +=
+                'ytd-promoted-sparkles-web-renderer,ytd-promoted-video-renderer,' +
+                'ytd-display-ad-renderer,ytd-ad-slot-renderer,ytd-in-feed-ad-layout-renderer,' +
+                'ytd-banner-promo-renderer,ytd-statement-banner-renderer,' +
+                'ytd-companion-slot-renderer,ytd-action-companion-ad-renderer,' +
+                'ytm-promoted-video-renderer,ytm-companion-ad-renderer,' +
+                'ytm-promoted-sparkles-web-renderer,ytm-search-promoted-video-renderer,' +
+                '.ytp-ad-overlay-container,.ytp-ad-overlay-slot,.ytp-ad-message-container,' +
+                '#masthead-ad,#player-ads,' +
+                'ytm-item-section-renderer:has(>*>ytm-companion-ad-renderer),' +
+                'ytm-item-section-renderer:has(>*>ytm-promoted-sparkles-web-renderer),' +
+                'ytm-item-section-renderer:has(>*>ytm-promoted-video-renderer),' +
+                'ytm-item-section-renderer:has(>*>ytm-search-promoted-video-renderer),' +
+                'ytm-item-section-renderer:has(>*>ytd-ad-slot-renderer),' +
+                // The "desktop site" grid feed uses different wrapper elements entirely: each
+                // card is a ytd-rich-item-renderer grid cell, so hiding just the ad renderer
+                // inside it still leaves an empty cell-shaped hole in the grid.
+                'ytd-rich-item-renderer:has(ytd-display-ad-renderer),' +
+                'ytd-rich-item-renderer:has(ytd-ad-slot-renderer),' +
+                'ytd-rich-item-renderer:has(ytd-promoted-sparkles-web-renderer),' +
+                'ytd-rich-item-renderer:has(ytd-statement-banner-renderer),' +
+                'ytd-rich-item-renderer:has(ytd-banner-promo-renderer),' +
+                // Ads can also occupy a whole grid row, or a section above/between rows, not
+                // just a single cell -- same empty-hole problem, one level up each time.
+                'ytd-rich-grid-row:has(ytd-display-ad-renderer),' +
+                'ytd-rich-grid-row:has(ytd-ad-slot-renderer),' +
+                'ytd-rich-grid-row:has(ytd-promoted-sparkles-web-renderer),' +
+                'ytd-rich-grid-row:has(ytd-statement-banner-renderer),' +
+                'ytd-rich-grid-row:has(ytd-banner-promo-renderer),' +
+                'ytd-rich-section-renderer:has(ytd-ad-slot-renderer),' +
+                'ytd-rich-section-renderer:has(ytd-display-ad-renderer),' +
+                'ytd-rich-section-renderer:has(ytd-statement-banner-renderer),' +
+                'ytd-rich-section-renderer:has(ytd-banner-promo-renderer),' +
+                'ytd-ad-slot-renderer,ytd-primetime-promo-renderer' +
+                '{display:none!important}';
+
+              // Sweep for anything still playing: press skip, or seek to the end of the ad.
+              var adTicks = 0;
+              var sweep = function () {
+                try {
+                  var skip = document.querySelector(
+                    '.ytp-ad-skip-button,.ytp-ad-skip-button-modern,.ytp-skip-ad-button,' +
+                    '.ytp-ad-skip-button-container button'
+                  );
+                  if (skip) { skip.click(); }
+                  var player = document.querySelector('.html5-video-player');
+                  if (player && player.classList.contains('ad-showing')) {
+                    // Only seek once the ad state has held for two ticks. Seeking during the
+                    // player's own transition makes it re-buffer, which looks like a stall.
+                    adTicks++;
+                    var video = player.querySelector('video');
+                    if (adTicks >= 2 && video && isFinite(video.duration) && video.duration > 0) {
+                      video.currentTime = video.duration;
+                    }
+                  } else {
+                    adTicks = 0;
+                  }
+                } catch (e) {}
+              };
+              setInterval(sweep, 700);
+            }
+
+            if (tweaksOn) {
+              styleRules +=
+                // The mobile site's fixed Home/Shorts/You bar and the "desktop site" grid's
+                // reel shelf section it sits inside of.
+                'ytm-pivot-bar-renderer,' +
+                'ytd-rich-section-renderer:has(ytd-reel-shelf-renderer),' +
+                // Shorts: a different, faster-cut format than the rest of the feed, and its
+                // vertical-video shelf doesn't fit a landscape car display well either way.
+                'ytm-reel-shelf-renderer,ytm-rich-shelf-renderer:has(ytm-reel-item-renderer),' +
+                'ytm-reel-item-renderer,ytd-reel-shelf-renderer,' +
+                // The "All / Podcasts / News / ..." filter chip row above the feed.
+                'ytm-chip-bar-renderer,ytm-feed-filter-chip-bar-renderer' +
+                '{display:none!important}';
+            }
+
+            if (styleRules) {
+              var style = document.createElement('style');
+              style.setAttribute('data-gearslip', 'youtube');
+              style.textContent = styleRules;
+              var root = document.head || document.documentElement;
+              if (root) { root.appendChild(style); }
+            }
+          } catch (e) {}
+        })();
+    """.trimIndent()
+}

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

@@ -23,19 +23,19 @@ data class Caller(val number: String, val name: String?) {
 sealed interface CallUiState {
     data object None : CallUiState
     data class Ringing(val caller: Caller, val canDecline: Boolean) : CallUiState
-    data class Active(val caller: Caller?) : CallUiState
+    /** [since] is the uptime the call went off-hook, for the timer. */
+    data class Active(val caller: Caller?, val since: Long) : CallUiState
 }
 
 /**
- * Tracks the phone's call state for the car screen, and answers or declines through the two
+ * Tracks the phone's call state for the car screen, and answers or declines through the
  * doors a sideloaded app can use: [android.telecom.TelecomManager.acceptRingingCall] to answer,
- * and [GearslipCallScreening]'s response to decline one that is still ringing.
+ * [GearslipCallScreening]'s response to decline one that is still ringing, and
+ * [android.telecom.TelecomManager.endCall] to hang up, which needs only ANSWER_PHONE_CALLS for an
+ * ordinary carrier call. Mute is the phone's microphone mute, put back when the call ends.
  *
- * 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.
+ * Call audio stays on the phone's normal voice path; nothing here sends it over the USB link,
+ * which only ever carries media playback.
  */
 object CarCalls {
 
@@ -47,9 +47,14 @@ object CarCalls {
     private var pendingRespond: ((allow: Boolean) -> Unit)? = null
     private var ringingCaller: Caller? = null
 
+    private val _muted = MutableStateFlow(false)
+    val muted: StateFlow<Boolean> = _muted.asStateFlow()
+    private var audio: android.media.AudioManager? = null
+
     fun start(context: Context) {
         if (watcher != null) return
         if (context.checkSelfPermission(Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) return
+        audio = context.getSystemService(android.media.AudioManager::class.java)
         val manager = context.getSystemService(TelephonyManager::class.java) ?: return
         val callback = object : TelephonyCallback(), TelephonyCallback.CallStateListener {
             override fun onCallStateChanged(state: Int) = onPhoneState(state)
@@ -66,6 +71,7 @@ object CarCalls {
         watcher = null
         pendingRespond = null
         ringingCaller = null
+        unmute()
         _state.value = CallUiState.None
     }
 
@@ -74,11 +80,15 @@ object CarCalls {
             TelephonyManager.CALL_STATE_IDLE -> {
                 pendingRespond = null
                 ringingCaller = null
+                // A mute left on would silence the microphone for everything after the call.
+                unmute()
                 _state.value = CallUiState.None
             }
             TelephonyManager.CALL_STATE_OFFHOOK -> {
                 pendingRespond = null
-                _state.value = CallUiState.Active(ringingCaller)
+                if (_state.value !is CallUiState.Active) {
+                    _state.value = CallUiState.Active(ringingCaller, android.os.SystemClock.uptimeMillis())
+                }
             }
             TelephonyManager.CALL_STATE_RINGING -> {
                 // The number itself only ever arrives through the screening service; if this
@@ -109,6 +119,39 @@ object CarCalls {
         runCatching { respond(false) }.onFailure { GearslipLog.w("calls: decline failed: ${it.message}") }
     }
 
+    /** A call Gearslip itself is placing, so the call pill can say who it's to. */
+    fun outgoingCall(context: Context, number: String) {
+        ringingCaller = Caller(number, lookUpName(context, number))
+    }
+
+    fun end(context: Context) {
+        if (context.checkSelfPermission(Manifest.permission.ANSWER_PHONE_CALLS) != PackageManager.PERMISSION_GRANTED) {
+            GearslipLog.w("calls: ending a call needs ANSWER_PHONE_CALLS, which was never granted")
+            return
+        }
+        val telecom = context.getSystemService(TelecomManager::class.java) ?: return
+        @Suppress("DEPRECATION")
+        runCatching { telecom.endCall() }
+            .onSuccess { if (!it) GearslipLog.w("calls: the phone wouldn't end the call") }
+            .onFailure { GearslipLog.w("calls: end failed: ${it.message}") }
+    }
+
+    fun toggleMute() {
+        val manager = audio ?: return
+        val want = !_muted.value
+        runCatching { manager.isMicrophoneMute = want }
+            .onFailure { GearslipLog.w("calls: mute failed: ${it.message}") }
+        // Read back rather than trusted: some phones let the call app overrule it.
+        _muted.value = manager.isMicrophoneMute
+        if (_muted.value != want) GearslipLog.w("calls: the phone didn't take the mute change")
+    }
+
+    private fun unmute() {
+        if (!_muted.value) return
+        runCatching { audio?.isMicrophoneMute = false }
+        _muted.value = false
+    }
+
     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")

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

@@ -0,0 +1,108 @@
+package app.seb3thehacker.gearslip.call
+
+import android.os.SystemClock
+import android.view.KeyEvent
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.Protobuf
+import app.seb3thehacker.gearslip.Wire
+import app.seb3thehacker.gearslip.car.CarKeys
+
+/**
+ * Tells the car about calls, so its own screens show them: the instrument cluster, the steering
+ * wheel display, the car's phone page. Android Auto does the same over the car's
+ * PhoneStatusService (Service field 10):
+ *
+ *   -> PhoneStatusUpdate { repeated PhoneCall calls = 1 }
+ *        PhoneCall { state = 1 (1 in call, 4 incoming, 6 muted); duration_seconds = 2;
+ *                    number = 3; name = 4 }
+ *   <- PhoneStatusInput { input = 1 { action = 1 (7 call) }; caller = 2; name = 3 }
+ *
+ * Read once a second from [CarCalls]. An update goes when the call changes, and every second
+ * while one is going, so the car's timer counts along; no calls goes once, as an empty list.
+ * The car's own call button answers through [CarKeys], like the steering wheel's.
+ */
+class CarPhoneStatus(
+    val channelId: Int,
+    private val sendOnChannel: (messageId: Int, body: ByteArray) -> Unit,
+) {
+    @Volatile private var running = false
+    private var sent: String? = null
+
+    fun onMessage(messageId: Int, body: ByteArray) {
+        when (messageId) {
+            MSG_CHANNEL_OPEN_RESPONSE -> {
+                val status = Protobuf.readInt32Field(body, 1)
+                GearslipLog.i("phone status: <- ChannelOpenResponse: status=$status")
+                if (status == 0) start()
+            }
+            MSG_INPUT -> onInput(body)
+            else -> GearslipLog.i("phone status: <- unhandled message id=$messageId (${body.size} bytes)")
+        }
+    }
+
+    private fun start() {
+        if (running) return
+        running = true
+        Thread({
+            while (running) {
+                runCatching { tick() }.onFailure { GearslipLog.w("phone status: ${it.message}") }
+                Thread.sleep(TICK_MS)
+            }
+        }, "gearslip-phone-status").start()
+    }
+
+    fun stop() {
+        running = false
+    }
+
+    private fun tick() {
+        val call = when (val state = CarCalls.state.value) {
+            CallUiState.None -> null
+            is CallUiState.Ringing -> Call(STATE_INCOMING, 0, state.caller)
+            is CallUiState.Active -> Call(
+                if (CarCalls.muted.value) STATE_MUTED else STATE_IN_CALL,
+                ((SystemClock.uptimeMillis() - state.since) / 1000).coerceAtLeast(0),
+                state.caller,
+            )
+        }
+        // Only a call that's going changes from one second to the next.
+        val key = call?.let { "${it.state}|${it.caller?.number}|${it.caller?.name}|${if (it.state == STATE_INCOMING) 0 else it.seconds}" } ?: ""
+        if (key == sent) return
+        val changed = call?.state != lastState
+        sent = key
+        lastState = call?.state
+        val body = call?.let { Protobuf.bytesField(1, it.encode()) } ?: ByteArray(0)
+        sendOnChannel(MSG_STATUS, body)
+        if (changed) GearslipLog.i("phone status: -> ${call?.let { STATE_NAMES[it.state] } ?: "no calls"}")
+    }
+
+    private var lastState: Int? = null
+
+    private class Call(val state: Int, val seconds: Long, val caller: Caller?) {
+        fun encode(): ByteArray {
+            var body = Protobuf.varintField(1, state.toLong()) + Protobuf.varintField(2, seconds)
+            caller?.number?.takeIf { it.isNotBlank() }?.let { body += Protobuf.stringField(3, it) }
+            caller?.name?.takeIf { it.isNotBlank() }?.let { body += Protobuf.stringField(4, it) }
+            return body
+        }
+    }
+
+    /** The car's own phone buttons. Only "call" does anything: it answers, as the wheel's does. */
+    private fun onInput(body: ByteArray) {
+        val action = Wire.bytes(Wire.fields(body), 1)?.let { Wire.varint(Wire.fields(it), 1)?.toInt() }
+        GearslipLog.i("phone status: <- input action=${action ?: "?"}")
+        if (action == ACTION_CALL) CarKeys.onKey(KeyEvent.KEYCODE_CALL, down = true, longPress = false)
+    }
+
+    companion object {
+        private const val TICK_MS = 1_000L
+        private const val MSG_CHANNEL_OPEN_RESPONSE = 8
+        private const val MSG_STATUS = 32769 // 0x8001
+        private const val MSG_INPUT = 32770 // 0x8002
+        private const val STATE_IN_CALL = 1
+        private const val STATE_INCOMING = 4
+        private const val STATE_MUTED = 6
+        private const val ACTION_CALL = 7
+        private val STATE_NAMES = mapOf(STATE_IN_CALL to "in a call", STATE_INCOMING to "ringing", STATE_MUTED to "in a call, muted")
+    }
+}

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

@@ -0,0 +1,65 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.grid.GridCells
+import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
+import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.remember
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.R
+import app.seb3thehacker.gearslip.mirror.PhoneApp
+import app.seb3thehacker.gearslip.mirror.PhoneApps
+import androidx.core.graphics.drawable.toBitmap
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+
+/**
+ * Launcher mode's app drawer: every app on the device, A to Z, each opened full screen. Gearslip
+ * comes first, for its own settings, which the car UI only partly covers.
+ */
+@Composable
+fun AllAppsScreen() {
+    val context = LocalContext.current
+    val apps by produceState(initialValue = PhoneApps.cached() ?: emptyList(), context) {
+        value = PhoneApps.cached() ?: withContext(Dispatchers.IO) { PhoneApps.installed(context).also { PhoneApps.warm(context) } }
+    }
+    val gearslip = remember(context) {
+        val label = context.packageManager.getApplicationLabel(context.applicationInfo).toString()
+        val icon = runCatching { context.packageManager.getApplicationIcon(context.packageName).toBitmap(ICON_PX, ICON_PX).asImageBitmap() }
+        PhoneApp(context.packageName, label, icon.getOrNull())
+    }
+
+    Column(Modifier.fillMaxSize().padding(start = 20.dp, end = 20.dp, top = 12.dp)) {
+        ScreenHeader(stringResource(R.string.app_all_apps))
+        Spacer(Modifier.height(12.dp))
+        LazyVerticalGrid(
+            columns = GridCells.Adaptive(minSize = 108.dp),
+            modifier = Modifier.fillMaxSize(),
+            contentPadding = PaddingValues(bottom = 16.dp),
+            horizontalArrangement = Arrangement.spacedBy(12.dp),
+            verticalArrangement = Arrangement.spacedBy(12.dp),
+        ) {
+            item {
+                PhoneAppTile(gearslip) { LauncherMode.launch(context, context.packageName) }
+            }
+            items(apps.sortedBy { it.label.lowercase() }) { app ->
+                PhoneAppTile(app) { LauncherMode.launch(context, app.packageName) }
+            }
+        }
+    }
+}
+
+private const val ICON_PX = 128

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

@@ -1,10 +1,14 @@
 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.
@@ -17,9 +21,16 @@ import kotlinx.coroutines.withContext
 object AssistantCommands {
 
     suspend fun handle(context: Context, navigator: CarNavigator, frame: CarEnvironment.Frame, heardRaw: String): String {
-        val heard = heardRaw.lowercase().trim()
+        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 }
@@ -29,6 +40,47 @@ object AssistantCommands {
         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(LauncherMode.active.value, LauncherMode.canCall(context)).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
@@ -42,29 +94,68 @@ object AssistantCommands {
         frame: CarEnvironment.Frame,
         heard: String,
     ): String? {
-        val trigger = NAVIGATE_TRIGGERS.firstOrNull { heard.startsWith(it) } ?: return null
-        var destination = heard.removePrefix(trigger).trim()
+        // "use Organic Maps to get to X", "open OsmAnd and navigate to X": the app comes first.
+        // "take me home", "go home": no "to", so no trigger would catch them.
+        var text = if (Regex("^(?:(?:take|bring|get|drive) me|go|drive|head|get|directions|go back|head back) home$").matches(heard)) {
+            "navigate to home"
+        } else {
+            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?"
 
-        var appName: String? = null
-        for (sep in listOf(" with ", " using ", " on ", " via ")) {
-            val at = destination.lastIndexOf(sep)
-            if (at > 0) {
-                appName = destination.substring(at + sep.length).trim()
+        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?"
+        // "home", "work", or a name from Saved places: its address is the search.
+        var spoken: String? = null
+        SavedPlaces.match(context, destination)?.let { (slot, saved) ->
+            val name = when (slot) {
+                SavedPlaces.HOME -> "home"
+                SavedPlaces.WORK -> "work"
+                else -> saved.label
+            }
+            if (saved.address.isBlank()) {
+                return "You haven't saved a $name address yet. Add it under Saved places in Gearslip's settings on your phone."
+            }
+            destination = saved.address
+            spoken = if (slot == SavedPlaces.HOME) "home" else "to $name"
+        }
 
-        val entries = LauncherCache.entries ?: withContext(Dispatchers.IO) { LauncherCache.load(context) }
-        val navApps = entries.filter { it.template?.isNavigation == true }
-        if (navApps.isEmpty()) return "You don't have any navigation apps installed."
-
-        val requestedApp = appName
-        val chosen = when {
-            requestedApp != null -> navApps.firstOrNull { it.label.lowercase().contains(requestedApp) }
-                ?: return "I couldn't find a navigation app called $requestedApp."
+        val chosen = chosenApp ?: when {
             navApps.size == 1 -> navApps.first()
             else -> navApps.firstOrNull { it.componentId == CarSettings.lastNav.value } ?: navApps.first()
         }
@@ -72,29 +163,105 @@ object AssistantCommands {
 
         CarServices.connectNav(template, frame, destination)
         navigator.home()
-        return "Navigating to $destination with ${chosen.label}."
+        spoken?.let { return "Navigating $it with ${chosen.label}." }
+        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") -> {
-                if (media.now.value.playing) media.togglePlay()
+            "pause" in heard || heard.startsWith("stop") || heard == "quiet" || heard == "shut up" -> {
+                media.pause()
+                VoiceFocus.afterRelease { media.pause() }
                 "Paused."
             }
-            "resume" in heard || (heard.startsWith("play") && "playing" !in heard) -> {
+            "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 -> {
+            "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 -> {
+            "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" 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."
@@ -104,11 +271,19 @@ object AssistantCommands {
     }
 
     private fun navCommand(navigator: CarNavigator, heard: String): String? = when {
-        "go home" in heard || heard == "home" -> {
+        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 -> {
+        "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."
         }
@@ -128,9 +303,10 @@ object AssistantCommands {
     }
 
     private fun infoCommand(heard: String): String? = when {
-        "what time" in heard || "what's the time" in heard ->
+        "what time" in heard || "what's the time" in heard || heard == "time" || "the time" in heard ->
             "It's ${DateFormat.getTimeInstance(DateFormat.SHORT).format(Date())}."
-        "weather" in heard -> {
+        "weather" in heard || "going to rain" in heard || "gonna rain" in heard || "how hot" in heard ||
+            "how cold" in heard || "temperature outside" in heard -> {
             val data = (Weather.state.value as? WeatherState.Ready)?.data
             if (data != null) "${data.temp}${data.tempUnit} and ${Weather.describe(data.code)} in ${data.place}."
             else "I don't have the weather yet."
@@ -139,12 +315,11 @@ object AssistantCommands {
     }
 
     private suspend fun callCommand(context: Context, heard: String): String? {
-        val name = when {
-            heard.startsWith("call ") -> heard.removePrefix("call ")
-            heard.startsWith("phone ") -> heard.removePrefix("phone ")
-            heard.startsWith("dial ") -> heard.removePrefix("dial ")
-            else -> return null
-        }.trim()
+        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."
 
@@ -162,21 +337,69 @@ object AssistantCommands {
         frame: CarEnvironment.Frame,
         heard: String,
     ): String? {
-        val name = when {
-            heard.startsWith("open ") -> heard.removePrefix("open ")
-            heard.startsWith("launch ") -> heard.removePrefix("launch ")
-            heard.startsWith("start ") -> heard.removePrefix("start ")
-            else -> return null
-        }.trim()
+        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
 
-        val entries = LauncherCache.entries ?: withContext(Dispatchers.IO) { LauncherCache.load(context) }
-        val match = entries.firstOrNull { it.label.lowercase().contains(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 NAVIGATE_TRIGGERS = listOf("navigate to ", "directions to ", "take me to ", "drive to ")
+    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

@@ -4,7 +4,21 @@ 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
@@ -25,49 +39,85 @@ 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.res.stringResource
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 
 /**
- * The band that appears while [CarAssistant] is listening, thinking or speaking - a thin strip
- * across the top, same idea as [CallOverlay]'s active-call banner, so it never blocks the screen
- * the driver was already looking at.
+ * 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
+    }
 
-    Surface(
-        color = MaterialTheme.colorScheme.primaryContainer,
-        contentColor = MaterialTheme.colorScheme.onPrimaryContainer,
-        modifier = modifier.fillMaxWidth(),
+    Box(
+        modifier
+            .fillMaxWidth()
+            .drawBehind {
+                // Dark enough by the text that nothing on the screen behind reads through it.
+                drawRect(Brush.verticalGradient(0f to Color.Transparent, 0.3f to Color.Black.copy(alpha = 0.8f), 1f to Color.Black.copy(alpha = 0.92f)))
+                // 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(
-            Modifier.padding(horizontal = 16.dp, vertical = 10.dp),
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(12.dp),
-        ) {
-            PulsingMic(state.phase == CarAssistant.Phase.LISTENING)
-            Column(Modifier.weight(1f)) {
+        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+            PulsingMic(listening)
+            Column(Modifier.weight(1f), horizontalAlignment = Alignment.CenterHorizontally) {
+                val listeningText = stringResource(R.string.assist_listening)
+                val momentText = stringResource(R.string.assist_one_moment)
+                val waiting = state.heard.isBlank() &&
+                    (state.phase == CarAssistant.Phase.LISTENING || state.phase == CarAssistant.Phase.THINKING)
+                val (small, big) = when (state.phase) {
+                    CarAssistant.Phase.LISTENING -> "" to state.heard.ifBlank { if (state.ready) listeningText else momentText }
+                    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(
-                    when (state.phase) {
-                        CarAssistant.Phase.LISTENING -> "Listening…"
-                        CarAssistant.Phase.THINKING -> "…"
-                        CarAssistant.Phase.SPEAKING -> state.reply
-                        CarAssistant.Phase.ERROR -> state.reply
-                        CarAssistant.Phase.IDLE -> ""
-                    },
-                    style = MaterialTheme.typography.titleSmall,
+                    big,
+                    color = if (waiting) 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.heard.isNotBlank() && state.phase != CarAssistant.Phase.SPEAKING) {
+                // What to say, until the driver starts saying it.
+                if (state.phase == CarAssistant.Phase.LISTENING && state.ready && state.heard.isBlank()) {
                     Text(
-                        "\"${state.heard}\"",
-                        style = MaterialTheme.typography.bodySmall,
+                        stringResource(R.string.assist_examples),
+                        color = Color.White.copy(alpha = 0.6f),
+                        style = MaterialTheme.typography.bodyMedium,
+                        textAlign = TextAlign.Center,
+                        maxLines = 2,
+                        modifier = Modifier.padding(top = 4.dp),
                     )
                 }
             }
@@ -76,9 +126,9 @@ fun AssistantOverlay(modifier: Modifier = Modifier) {
                     context.startActivity(
                         Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", context.packageName, null)),
                     )
-                }) { Text("Grant") }
+                }) { Text(stringResource(R.string.assist_grant)) }
             }
-            GsIconButton(Icons.Filled.Close, "Dismiss", CarAssistant::cancel)
+            GsIconButton(Icons.Filled.Close, stringResource(R.string.msg_dismiss), CarAssistant::cancel)
         }
     }
 }

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

@@ -0,0 +1,179 @@
+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 app.seb3thehacker.gearslip.R
+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.
+ *
+ * Many cars switch Bluetooth music off while Android Auto runs and want it over Android Auto
+ * instead (a Skoda, a VW, an Audi, a Bolt). If the phone's Bluetooth audio to the car was up when
+ * the car showed Gearslip and drops after, that's what happened: this car's music goes through
+ * Gearslip from now on, and the car screen says so.
+ */
+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
+    /** Whether Bluetooth audio to the car was up when the car showed Gearslip; null until known. */
+    private var connectedAtStart: Boolean? = 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
+        connectedAtStart = null
+        audioToCar { connectedAtStart = it }
+        main.postDelayed(::start, WAIT_MS)
+    }
+
+    fun onCarDisconnected() = main.post {
+        armed = false
+        connectedAtStart = null
+        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.pipesNow) {
+            set(false, "audio goes through Gearslip")
+            return
+        }
+        audioToCar { ok ->
+            if (ok == null) return@audioToCar
+            if (!ok && connectedAtStart == true) return@audioToCar switchToGearslip()
+            if (!CarSettings.bluetoothWarning.value) {
+                set(false, "the warning is turned off")
+                return@audioToCar
+            }
+            set(!ok, if (ok) "connected to the car" else "not connected to the car")
+        }
+    }
+
+    /** The car dropped Bluetooth music once Gearslip was up: send this car's music through Gearslip. */
+    private fun switchToGearslip() {
+        val car = CarBluetooth.carAddress ?: return
+        val context = appContext ?: return
+        if (!app.seb3thehacker.gearslip.audio.CarAudio.sinkOffered) return
+        log.i("Bluetooth audio: the car turned it off with Gearslip running, so this car's music goes through Gearslip")
+        CarSettings.rememberAudioCar(car)
+        set(false, "audio goes through Gearslip")
+        app.seb3thehacker.gearslip.audio.CarAudio.request()
+        CarToasts.show(this, context.getString(R.string.car_audio_switched), androidx.car.app.CarToast.LENGTH_LONG)
+    }
+
+    /**
+     * Whether the phone's Bluetooth audio is connected to the car, on the main thread: null when
+     * that can't be told (no permission). Bluetooth switched off counts as not connected.
+     */
+    @SuppressLint("MissingPermission")
+    private fun audioToCar(result: (Boolean?) -> Unit) {
+        val context = appContext ?: return result(null)
+        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 result(null)
+        }
+        val adapter = context.getSystemService(BluetoothManager::class.java)?.adapter ?: return result(null)
+        if (!adapter.isEnabled) return result(false)
+        val car = CarBluetooth.carAddress?.uppercase()
+        val asked = 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 { result(ok) }
+            }
+
+            override fun onServiceDisconnected(profile: Int) {}
+        }, BluetoothProfile.A2DP)
+        if (!asked) result(null)
+    }
+
+    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 +1,116 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.ui.res.stringResource
+import app.seb3thehacker.gearslip.R
+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 && !CarSettings.thisCarPipes.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 = stringResource(R.string.home_bt_title),
+                body = stringResource(R.string.overlay_bt_body),
+                secondary = stringResource(R.string.overlay_dont_show) to BluetoothAudioCheck::neverAgain,
+                primary = stringResource(R.string.overlay_ok) to BluetoothAudioCheck::dismissOnCar,
+            ) else if (locationOff && !locationDismissed) PairCard(
+                title = stringResource(R.string.overlay_location_off),
+                body = stringResource(R.string.overlay_location_body),
+                secondary = stringResource(R.string.overlay_dont_show) to LocationCheck::neverAgain,
+                primary = stringResource(R.string.overlay_ok) to LocationCheck::dismissOnCar,
+            )
+        }
+        CarBluetooth.Prompt.ASK -> PairCard(
+            title = stringResource(R.string.overlay_pair_title),
+            body = stringResource(if (bluetoothAudio) R.string.overlay_pair_body_music else R.string.overlay_pair_body),
+            secondary = stringResource(R.string.worked_not_now) to CarBluetooth::notNow,
+            primary = stringResource(R.string.overlay_pair) to CarBluetooth::pair,
+        )
+        CarBluetooth.Prompt.PAIRING -> PairCard(
+            title = stringResource(R.string.overlay_confirm_title),
+            body = stringResource(R.string.overlay_confirm_body),
+            secondary = null,
+            primary = stringResource(R.string.carset_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/BrowserStartPage.kt

@@ -0,0 +1,182 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.Image
+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.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.lazy.grid.GridCells
+import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
+import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+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.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.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+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 app.seb3thehacker.gearslip.R
+import app.seb3thehacker.gearslip.browser.Bookmark
+import app.seb3thehacker.gearslip.browser.BrowserSettings
+import app.seb3thehacker.gearslip.browser.SiteIcons
+import app.seb3thehacker.gearslip.car.theme.GsIconBox
+import app.seb3thehacker.gearslip.car.theme.GsTone
+import app.seb3thehacker.gearslip.car.theme.gsColors
+import app.seb3thehacker.gearslip.car.theme.gsShape
+
+/** How wide a tile is, icon and label together; the grid fits as many as the screen allows. */
+private val TILE_WIDTH = 112.dp
+private val ICON_SIZE = 64.dp
+private val SEARCH_MAX_WIDTH = 560.dp
+/** Five tiles across at most, so a short list sits in the middle instead of along the left. */
+private val GRID_MAX_WIDTH = TILE_WIDTH * 5
+/** Room above each tile for the remove button, which sits on the icon's corner. */
+private val REMOVE_ROOM = 10.dp
+
+/**
+ * What the browser shows before a page is open: a search bar, and the bookmarks as big tiles.
+ * Holding a tile shows a remove button on every tile, as a launcher does; tapping anywhere
+ * else, or Done, puts them away. Adding happens from the browser's star, or on the phone.
+ */
+@Composable
+internal fun BrowserStartPage(onOpen: (String) -> Unit, onSearch: () -> Unit, onAdd: () -> Unit) {
+    val bookmarks by BrowserSettings.bookmarks.collectAsState()
+    var editing by remember { mutableStateOf(false) }
+    if (bookmarks.isEmpty()) editing = false
+
+    // A narrow, centred column: on a wide car screen a bar from edge to edge reads as a toolbar
+    // rather than a search box, and tiles spread across it look scattered.
+    Column(
+        Modifier.fillMaxSize().padding(horizontal = 16.dp).padding(top = 24.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.spacedBy(20.dp),
+    ) {
+        SearchBar(onSearch)
+        LazyVerticalGrid(
+            columns = GridCells.Adaptive(TILE_WIDTH),
+            contentPadding = PaddingValues(bottom = 16.dp),
+            horizontalArrangement = Arrangement.Center,
+            verticalArrangement = Arrangement.spacedBy(8.dp),
+            modifier = Modifier.widthIn(max = GRID_MAX_WIDTH).fillMaxSize(),
+        ) {
+            items(bookmarks, key = { it.url }) { bookmark ->
+                BookmarkTile(
+                    bookmark,
+                    editing = editing,
+                    onClick = { if (editing) editing = false else onOpen(bookmark.url) },
+                    onHold = { editing = true },
+                    onRemove = { BrowserSettings.removeBookmark(bookmark.url) },
+                )
+            }
+            item(key = "add") {
+                Box(Modifier.padding(top = REMOVE_ROOM)) {
+                if (editing) {
+                    Tile(stringResource(R.string.web_done), onClick = { editing = false }) {
+                        Icon(Icons.Filled.Close, null, Modifier.size(28.dp))
+                    }
+                } else {
+                    Tile(stringResource(R.string.web_add_bookmark), onClick = onAdd) {
+                        Icon(Icons.Filled.Add, null, Modifier.size(28.dp))
+                    }
+                }
+                }
+            }
+        }
+    }
+}
+
+/** Looks like a text field, but opens the car keyboard: the same as the header's Search. */
+@Composable
+private fun SearchBar(onSearch: () -> Unit) {
+    val colors = gsColors(GsTone.Neutral)
+    GsIconBox(onSearch, Modifier.widthIn(max = SEARCH_MAX_WIDTH).fillMaxWidth().height(56.dp), colors, shape = CircleShape) {
+        Row(Modifier.fillMaxWidth().padding(horizontal = 20.dp), verticalAlignment = Alignment.CenterVertically) {
+            Icon(Icons.Filled.Search, null, Modifier.size(24.dp))
+            Text(
+                stringResource(R.string.web_search),
+                style = MaterialTheme.typography.bodyLarge,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = Modifier.padding(start = 12.dp),
+            )
+        }
+    }
+}
+
+@Composable
+private fun BookmarkTile(bookmark: Bookmark, editing: Boolean, onClick: () -> Unit, onHold: () -> Unit, onRemove: () -> Unit) {
+    val context = LocalContext.current
+    val host = bookmark.host
+    val version by SiteIcons.version.collectAsState()
+    LaunchedEffect(host) { SiteIcons.fetch(context, host) }
+    val icon = remember(host, version) { SiteIcons.icon(context, host) }
+    // The remove button overhangs the icon's corner, into the room left above it, so nothing
+    // clips it: neither the grid's edge nor the next row.
+    Box(Modifier.width(TILE_WIDTH).padding(top = REMOVE_ROOM)) {
+        Tile(bookmark.title, onClick = onClick, onHold = onHold) {
+            if (icon != null) {
+                Image(icon.asImageBitmap(), null, Modifier.size(40.dp).clip(gsShape()))
+            } else {
+                Text(
+                    bookmark.title.firstOrNull()?.uppercase() ?: "?",
+                    style = MaterialTheme.typography.headlineMedium,
+                    fontWeight = FontWeight.Bold,
+                )
+            }
+        }
+        if (editing) {
+            GsIconBox(
+                onRemove,
+                Modifier.align(Alignment.TopCenter).offset(x = ICON_SIZE / 2, y = -REMOVE_ROOM).size(28.dp),
+                gsColors(GsTone.Danger),
+                shape = CircleShape,
+            ) {
+                Icon(Icons.Filled.Close, stringResource(R.string.web_remove_bookmark, bookmark.title), Modifier.size(18.dp))
+            }
+        }
+    }
+}
+
+/** An icon box with its label under it, the start page's one shape. */
+@Composable
+private fun Tile(label: String, onClick: () -> Unit, onHold: (() -> Unit)? = null, icon: @Composable () -> Unit) {
+    Column(Modifier.width(TILE_WIDTH), horizontalAlignment = Alignment.CenterHorizontally, verticalArrangement = Arrangement.spacedBy(6.dp)) {
+        GsIconBox(onClick, Modifier.size(ICON_SIZE), gsColors(GsTone.Tonal), onLongClick = onHold) { icon() }
+        Text(
+            label,
+            style = MaterialTheme.typography.labelLarge,
+            color = MaterialTheme.colorScheme.onSurface,
+            textAlign = TextAlign.Center,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.fillMaxWidth().padding(horizontal = 4.dp),
+        )
+    }
+}

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

@@ -1,5 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.ui.res.stringResource
+import app.seb3thehacker.gearslip.R
 import androidx.compose.foundation.shape.CircleShape
 import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.layout.Arrangement
@@ -33,21 +35,17 @@ 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].
+ * Takes the whole car screen while a call is ringing, because nothing else matters more right
+ * now. A call under way moves into the nav bar instead (see NavCallPill), so it covers nothing.
  */
 @Composable
-fun CallOverlay(modifier: Modifier = Modifier) {
+fun CallOverlay() {
     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 -> {}
+        else -> {}
     }
 }
 
@@ -67,7 +65,7 @@ private fun IncomingCall(s: CallUiState.Ringing, onAnswer: () -> Unit, onDecline
             )
             Spacer(Modifier.height(16.dp))
             Text(
-                "Incoming call",
+                stringResource(R.string.call_incoming),
                 style = MaterialTheme.typography.titleMedium,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
             )
@@ -80,13 +78,13 @@ private fun IncomingCall(s: CallUiState.Ringing, onAnswer: () -> Unit, onDecline
             )
             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)
+                CallButton(Icons.Filled.Close, stringResource(R.string.call_decline), MaterialTheme.colorScheme.error, enabled = s.canDecline, onClick = onDecline)
+                CallButton(Icons.Filled.Call, stringResource(R.string.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.",
+                    stringResource(R.string.call_ringing),
                     style = MaterialTheme.typography.bodySmall,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
@@ -110,25 +108,3 @@ private fun CallButton(icon: ImageVector, label: String, color: Color, enabled:
         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/CarAlerts.kt

@@ -0,0 +1,203 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.annotation.MainThread
+import androidx.car.app.model.Action
+import androidx.car.app.model.Alert
+import androidx.car.app.model.AlertCallback
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.LinearEasing
+import androidx.compose.animation.core.tween
+import androidx.compose.foundation.background
+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.Spacer
+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.layout.widthIn
+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.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.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.res.stringResource
+import androidx.compose.ui.semantics.LiveRegionMode
+import androidx.compose.ui.semantics.liveRegion
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.R
+import app.seb3thehacker.gearslip.car.theme.GsColors
+import app.seb3thehacker.gearslip.car.theme.GsIconBox
+import app.seb3thehacker.gearslip.host.cancel
+import app.seb3thehacker.gearslip.host.click
+import app.seb3thehacker.gearslip.host.color
+import app.seb3thehacker.gearslip.host.dismissed
+import app.seb3thehacker.gearslip.host.text
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/**
+ * The one alert on the car screen, from whichever hosted app sent it: Waze asking whether a
+ * hazard is still there, say. As in Android Auto, a newer alert replaces the one showing, and it
+ * shows over any screen, since a question about the road matters while music is up too.
+ */
+@MainThread
+internal object CarAlerts {
+    class Shown(val owner: Any, val alert: Alert)
+
+    private val current = MutableStateFlow<Shown?>(null)
+    val shown: StateFlow<Shown?> = current.asStateFlow()
+
+    fun show(owner: Any, alert: Alert) {
+        val old = current.value
+        current.value = Shown(owner, alert)
+        GearslipLog.i("host: alert ${alert.id} \"${alert.title.text()}\" with ${alert.actions.size} buttons")
+        if (old != null && !(old.owner === owner && old.alert.id == alert.id)) old.alert.callbackDelegate.dismissed()
+    }
+
+    /** The app took its alert down; a no-op unless that alert is the one showing. */
+    fun dismiss(owner: Any, id: Int) {
+        val shown = current.value ?: return
+        if (shown.owner !== owner || shown.alert.id != id) return
+        current.value = null
+        shown.alert.callbackDelegate.dismissed()
+    }
+
+    /** The driver tapped one of its buttons: the app gets the tap, and the alert goes. */
+    fun tapped(shown: Shown, action: Action) {
+        action.onClickDelegate.click("alert button")
+        if (current.value !== shown) return
+        current.value = null
+        shown.alert.callbackDelegate.dismissed()
+    }
+
+    fun cancelled(shown: Shown, reason: Int) {
+        if (current.value !== shown) return
+        current.value = null
+        shown.alert.callbackDelegate.cancel(reason)
+    }
+
+    /** The app disconnected: its alert goes with it, and there is no one left to tell. */
+    fun clear(owner: Any) {
+        if (current.value?.owner === owner) current.value = null
+    }
+}
+
+@Composable
+internal fun CarAlertOverlay(modifier: Modifier = Modifier) {
+    val current by CarAlerts.shown.collectAsState()
+    val shown = current ?: return
+    val alert = shown.alert
+    val timed = alert.durationMillis in 1 until Alert.DURATION_SHOW_INDEFINITELY
+    // What's left of the alert's time, drawn as the bar along its foot.
+    val left = remember(shown) { Animatable(1f) }
+    LaunchedEffect(shown) {
+        if (!timed) return@LaunchedEffect
+        left.animateTo(0f, tween(alert.durationMillis.coerceAtMost(Int.MAX_VALUE.toLong()).toInt(), easing = LinearEasing))
+        CarAlerts.cancelled(shown, AlertCallback.REASON_TIMEOUT)
+    }
+    val scheme = MaterialTheme.colorScheme
+    val dark = scheme.surface.luminanceIsDark()
+    Surface(
+        modifier
+            .padding(horizontal = 24.dp, vertical = 16.dp)
+            .widthIn(max = 640.dp)
+            .fillMaxWidth()
+            .semantics { liveRegion = LiveRegionMode.Polite },
+        shape = RoundedCornerShape(24.dp),
+        color = scheme.surfaceContainerHigh,
+        shadowElevation = 8.dp,
+    ) {
+        Column {
+            Row(Modifier.padding(start = 20.dp, end = 12.dp, top = 16.dp), verticalAlignment = Alignment.CenterVertically) {
+                if (alert.icon != null) {
+                    CarGlyph(alert.icon, Modifier.size(40.dp))
+                    Spacer(Modifier.width(16.dp))
+                }
+                Column(Modifier.weight(1f)) {
+                    Text(
+                        alert.title.text(),
+                        style = MaterialTheme.typography.titleLarge,
+                        fontWeight = FontWeight.Bold,
+                        maxLines = 2,
+                        overflow = TextOverflow.Ellipsis,
+                    )
+                    alert.subtitle?.text()?.takeIf { it.isNotEmpty() }?.let {
+                        Text(
+                            it,
+                            style = MaterialTheme.typography.titleMedium,
+                            color = scheme.onSurfaceVariant,
+                            maxLines = 2,
+                            overflow = TextOverflow.Ellipsis,
+                        )
+                    }
+                }
+                // With no timer and no buttons, nothing else would ever take it away.
+                if (!timed || alert.actions.isEmpty()) {
+                    GsIconBox(
+                        onClick = { CarAlerts.cancelled(shown, AlertCallback.REASON_USER_ACTION) },
+                        modifier = Modifier.size(56.dp),
+                        colors = GsColors(Color.Transparent, scheme.onSurface),
+                        shape = CircleShape,
+                    ) {
+                        Icon(Icons.Filled.Close, contentDescription = stringResource(R.string.close))
+                    }
+                }
+            }
+            if (alert.actions.isNotEmpty()) {
+                Row(
+                    Modifier.fillMaxWidth().padding(horizontal = 20.dp, vertical = 16.dp),
+                    horizontalArrangement = Arrangement.spacedBy(12.dp),
+                ) {
+                    alert.actions.take(2).forEach { action ->
+                        val custom = action.backgroundColor?.type?.let { it != androidx.car.app.model.CarColor.TYPE_DEFAULT } == true
+                        GsIconBox(
+                            onClick = { CarAlerts.tapped(shown, action) },
+                            modifier = Modifier.weight(1f).height(64.dp),
+                            colors = GsColors(
+                                action.backgroundColor.color(dark, scheme.surfaceContainerHighest),
+                                if (custom) Color.White else scheme.onSurface,
+                            ),
+                            enabled = action.isEnabled,
+                        ) {
+                            Row(verticalAlignment = Alignment.CenterVertically) {
+                                if (action.icon != null) {
+                                    CarGlyph(action.icon, Modifier.size(28.dp))
+                                    Spacer(Modifier.width(8.dp))
+                                }
+                                Text(action.title.text(), style = MaterialTheme.typography.titleMedium, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                            }
+                        }
+                    }
+                }
+            } else {
+                Spacer(Modifier.height(16.dp))
+            }
+            if (timed) {
+                Box(Modifier.fillMaxWidth().height(4.dp).background(scheme.surfaceContainerHighest)) {
+                    Box(Modifier.fillMaxWidth(left.value).height(4.dp).clip(RoundedCornerShape(2.dp)).background(scheme.primary))
+                }
+            }
+        }
+    }
+}

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

@@ -1,5 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.ui.res.stringResource
+import app.seb3thehacker.gearslip.R
 import app.seb3thehacker.gearslip.car.theme.*
 import android.view.SurfaceHolder
 import android.view.SurfaceView
@@ -11,11 +13,14 @@ 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.fillMaxHeight
+import androidx.compose.foundation.layout.width
 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.layout.height
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
@@ -34,8 +39,11 @@ 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.layout.boundsInWindow
+import androidx.compose.ui.layout.onGloballyPositioned
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.ui.viewinterop.AndroidView
 import app.seb3thehacker.gearslip.GearslipLog
 import app.seb3thehacker.gearslip.host.CarAppConnection
@@ -59,13 +67,44 @@ fun CarAppStage(
 ) {
     val template by connection.template.collectAsStateWithLifecycle()
 
+    val cover = remember { ChromeCover() }
+    val navBar = LocalNavBarInset.current
+
     Box(Modifier.fillMaxSize()) {
         // The app's own drawing goes underneath; everything else is the host's rendering of
         // the template it described, laid over the top.
-        if (status.surfaceRequested) {
-            AppSurface(connection, frame, template, Modifier.fillMaxSize())
+        androidx.compose.runtime.CompositionLocalProvider(LocalChromeCover provides cover, LocalCarAppConnection provides connection) {
+            // A place list's map is the host's to draw; any other map is the app's own surface.
+            val placeList = template as? androidx.car.app.model.PlaceListMapTemplate
+            if (placeList != null) {
+                HostPlaceMap(placeList, Modifier.fillMaxSize())
+            } else if (status.surfaceRequested) {
+                AppSurface(connection, frame, template, embedded, Modifier.fillMaxSize())
+            }
+            // The docked player floats over one side of the map: the chrome keeps clear of it,
+            // and the app hears that side is covered, so its map centres in the rest.
+            val panel = LocalSidePanelInset.current
+            val panelAtStart = LocalCardsAtEnd.current
+            TemplateChrome(
+                template,
+                Modifier.fillMaxSize().padding(
+                    top = if (embedded) 0.dp else CHROME_BAR,
+                    bottom = navBar,
+                    start = if (panelAtStart) panel else 0.dp,
+                    end = if (panelAtStart) 0.dp else panel,
+                ),
+            )
+            if (panel > 0.dp) {
+                Box(
+                    Modifier
+                        .align(if (panelAtStart) Alignment.CenterStart else Alignment.CenterEnd)
+                        .fillMaxHeight()
+                        .width(panel)
+                        .covers("side-panel", if (panelAtStart) CoverEdge.START else CoverEdge.END),
+                )
+            }
+            BottomCover(navBar, Modifier.align(Alignment.BottomCenter))
         }
-        TemplateChrome(template, Modifier.fillMaxSize().padding(top = if (embedded) 0.dp else CHROME_BAR))
         if (!embedded) ChromeBar(status, onDisconnect, Modifier.align(Alignment.TopCenter))
     }
 }
@@ -81,17 +120,51 @@ private fun AppSurface(
     connection: CarAppConnection,
     frame: CarEnvironment.Frame,
     template: Template?,
+    embedded: Boolean,
     modifier: Modifier = Modifier,
 ) {
     var size by remember { mutableStateOf(0 to 0) }
+    var bounds by remember { mutableStateOf<androidx.compose.ui.geometry.Rect?>(null) }
+    val cover = LocalChromeCover.current
 
-    // The app lays its map out around whatever the host covers, so a template change moves the
-    // visible area even though the surface itself hasn't changed.
-    LaunchedEffect(template, size) {
-        val (width, height) = size
+    // The app lays its map out around whatever the host covers, so a template change or a card
+    // changing size moves the visible area even though the surface itself hasn't changed.
+    val (width, height) = size
+    // A full-screen map takes the knob: turn to zoom, nudge to pan, press for its buttons. The
+    // home screen's map pane leaves it alone, so the knob still moves between the cards there.
+    val focusManager = androidx.compose.ui.platform.LocalFocusManager.current
+    val isMap = !embedded && !isContentTemplate(template)
+    DisposableEffect(connection, isMap, width, height) {
+        if (!isMap || width == 0 || height == 0) return@DisposableEffect onDispose {}
+        val knob = MapKnob(connection, width, height) { focusManager.clearFocus() }
+        CarKeys.knobTaker = knob
+        onDispose {
+            knob.release()
+            if (CarKeys.knobTaker === knob) CarKeys.knobTaker = null
+        }
+    }
+    val measured = bounds?.takeIf { width > 0 && height > 0 }?.let { cover?.visibleWithin(it, width, height) }
+    // The card column moves the map's centre but isn't taken out of the stable area: apps size
+    // their own overlays from it, and Vela's speedometer shrank to fit the strip right of the cards.
+    val cardsAtEnd = LocalCardsAtEnd.current
+    val cardEdge = cardEdge
+    val measuredStable = bounds?.takeIf { width > 0 && height > 0 }?.let { cover?.visibleWithin(it, width, height, skip = cardEdge) }
+    // A little room above whatever ends the map at the bottom (the nav bar, or the screen's edge):
+    // apps draw their own corner pieces (Waze's speedometer) right on the area's bottom edge,
+    // which left them sitting flush on the bar.
+    val bottomGap = with(androidx.compose.ui.platform.LocalDensity.current) { MAP_BOTTOM_GAP.roundToPx() }
+    LaunchedEffect(template, size, measured, measuredStable, cardsAtEnd, bottomGap) {
         if (width > 0 && height > 0) {
-            val visible = visibleAreaFor(template, width, height)
-            connection.reportAreas(visible = visible, stable = visible)
+            fun android.graphics.Rect.clearOfBar() = if (isEmpty) this else android.graphics.Rect(left, top, right, maxOf(top, bottom - bottomGap))
+            val visible = visibleAreaFor(template, width, height, measured, cardsAtEnd).clearOfBar()
+            // Waze seems to centre its car in the stable area rather than the visible one, so it
+            // gets the cards taken out of that too. Test: see whether its car moves out from under them.
+            val stable = if (!isContentTemplate(template) && connection.appPackage != "com.waze") {
+                visibleAreaFor(template, width, height, measuredStable, cardsAtEnd).clearOfBar()
+            } else {
+                visible
+            }
+            connection.reportAreas(visible = visible, stable = stable)
         }
     }
 
@@ -101,7 +174,9 @@ private fun AppSurface(
     // 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) {
+    androidx.compose.foundation.layout.BoxWithConstraints(
+        modifier.onGloballyPositioned { bounds = it.boundsInWindow() },
+    ) {
         val epoch by connection.surfaceEpoch.collectAsState()
         androidx.compose.runtime.key(constraints.maxWidth, constraints.maxHeight, epoch) {
             SurfaceHost(connection, frame, onSize = { size = it }, Modifier.fillMaxSize())
@@ -189,34 +264,43 @@ private fun ChromeBar(
     onDisconnect: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
+    // The app's name and a way out, nothing else: which template is showing, or whether the
+    // app has drawn yet, is for the log, not the driver.
     Surface(
-        color = Color.Black.copy(alpha = 0.55f),
-        contentColor = Color.White,
-        modifier = modifier.fillMaxWidth(),
+        color = MaterialTheme.colorScheme.surfaceContainer,
+        contentColor = MaterialTheme.colorScheme.onSurface,
+        modifier = modifier.fillMaxWidth().height(CHROME_BAR),
     ) {
         Row(
-            Modifier.padding(horizontal = 16.dp, vertical = 6.dp),
+            Modifier.padding(horizontal = 16.dp),
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            Column(Modifier.weight(1f)) {
-                Text(
-                    status.app ?: "Car app",
-                    style = MaterialTheme.typography.titleSmall,
-                    fontWeight = FontWeight.SemiBold,
-                )
-                val detail = buildList {
-                    status.template?.let { add(it) }
-                    add(if (status.surfaceAttached) "drawing" else "waiting for the app")
-                }.joinToString(" - ")
-                Text(detail, style = MaterialTheme.typography.bodySmall)
-            }
-            GsButton(onClick = onDisconnect, tone = GsTone.Tonal) { Text("Stop") }
+            Text(
+                status.app ?: stringResource(R.string.stage_car_app),
+                style = MaterialTheme.typography.titleSmall,
+                fontWeight = FontWeight.SemiBold,
+                modifier = Modifier.weight(1f),
+            )
+            GsIconButton(
+                androidx.compose.material.icons.Icons.Filled.Close,
+                status.app?.let { stringResource(R.string.stage_close, it) } ?: stringResource(R.string.stage_close_app),
+                onDisconnect,
+                size = 36.dp,
+                iconSize = 20.dp,
+                shape = androidx.compose.foundation.shape.CircleShape,
+            )
         }
     }
 }
 
+/** How far above the bottom of the map the area an app may draw in stops. */
+private val MAP_BOTTOM_GAP = 12.dp
+
 /** 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
+
+/** The app connection a template on screen belongs to: the map app's, or the one opened from the launcher. */
+internal val LocalCarAppConnection = androidx.compose.runtime.staticCompositionLocalOf { CarServices.nav }

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

@@ -1,6 +1,9 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.annotation.StringRes
+import app.seb3thehacker.gearslip.R
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.List
 import androidx.compose.material.icons.filled.Call
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material.icons.filled.Share
@@ -13,7 +16,9 @@ import app.seb3thehacker.gearslip.ProjectedContent
 /** One tile in the launcher and the screen it opens. */
 class CarApp(
     val id: String,
+    /** English, for matching what a driver says; [labelRes] is what the screen shows. */
     val label: String,
+    @param:StringRes val labelRes: Int,
     val icon: ImageVector,
     val content: @Composable () -> Unit,
 )
@@ -22,19 +27,28 @@ class CarApp(
 object CarApps {
 
     val all: List<CarApp> = listOf(
-        CarApp("web", "Web", Icons.Filled.Search) {
+        CarApp("web", "Browser", R.string.app_browser, Icons.Filled.Search) {
             WebApp(content = ProjectedContent.resolve(LocalContext.current))
         },
-        CarApp("phone", "Screen sharing", Icons.Filled.Share) {
+        CarApp("phone", "Screen sharing", R.string.app_screen_sharing, Icons.Filled.Share) {
             PhoneAppsScreen()
         },
-        CarApp("dialer", "Phone", Icons.Filled.Call) {
+        CarApp("dialer", "Phone", R.string.carset_phone, Icons.Filled.Call) {
             PhoneDialerScreen()
         },
-        CarApp("settings", "Settings", Icons.Filled.Settings) {
+        CarApp("settings", "Settings", R.string.settings_title, Icons.Filled.Settings) {
             CarSettingsScreen()
         },
+        CarApp("allapps", "All apps", R.string.app_all_apps, Icons.Filled.List) {
+            AllAppsScreen()
+        },
     )
 
     fun find(id: String): CarApp? = all.firstOrNull { it.id == id }
+
+    /** The screens [BuiltInApps.entries] offers here, so a choice list never names a hidden one. */
+    fun shown(launcher: Boolean, canCall: Boolean): List<CarApp> {
+        val ids = BuiltInApps.entries(launcher, canCall).mapNotNull { (it.builtIn?.screen as? CarScreen.App)?.id }.toSet()
+        return all.filter { it.id in ids }
+    }
 }

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

@@ -38,6 +38,8 @@ object CarAssistant {
         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())
@@ -89,6 +91,7 @@ object CarAssistant {
         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 ->
@@ -174,15 +177,16 @@ object CarAssistant {
         onSpeaking: () -> Unit = {},
     ) {
         cancel()
-        listenOnce(onPartial, onHeard = {}, onResult, onError, cue, onSpeaking)
+        listenOnce(onPartial, onHeard = {}, onResult = onResult, onError = onError, cue = cue, onSpeaking = onSpeaking)
     }
 
     /**
-     * One phrase, through Gearslip's own [SpeechEngine]. The phone's recognizer is only a fallback
-     * for when the engine itself can't run, since plenty of phones (GrapheneOS among them) have none.
+     * 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,
@@ -190,24 +194,24 @@ object CarAssistant {
         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 = { message ->
-                if (message == SpeechEngine.NOT_LOADED && SpeechRecognizer.isRecognitionAvailable(context)) {
-                    systemListen(context, onPartial, onHeard, onResult, onError)
-                } else {
-                    onError(message)
-                }
-            },
+            onError = onError,
         )
     }
 
     private fun systemListen(
         context: Context,
+        onListening: () -> Unit,
         onPartial: (String) -> Unit,
         onHeard: () -> Unit,
         onResult: (String) -> Unit,
@@ -216,7 +220,7 @@ object CarAssistant {
         val r = SpeechRecognizer.createSpeechRecognizer(context)
         recognizer = r
         r.setRecognitionListener(object : RecognitionListener {
-            override fun onReadyForSpeech(params: Bundle?) {}
+            override fun onReadyForSpeech(params: Bundle?) = onListening()
             override fun onBeginningOfSpeech() {}
             override fun onRmsChanged(rmsdB: Float) {}
             override fun onBufferReceived(buffer: ByteArray?) {}

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

@@ -0,0 +1,404 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.annotation.StringRes
+import app.seb3thehacker.gearslip.R
+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.
+ *
+ * The one exception is a driver who typed the phone's real address into Settings. A VW MIB2 drops
+ * an already paired phone's Bluetooth when it connects over USB, because nothing tells it the two
+ * are the same phone (issue #28). With the address, Gearslip opens the channel on every connection
+ * and sends the same request, which is how Android Auto says so.
+ */
+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, how to open and write to it, and who hears its answers. */
+    private class Car(
+        val service: ServiceDiscovery.BluetoothService,
+        val open: () -> Unit,
+        val send: (messageId: Int, body: ByteArray) -> Unit,
+        val answered: () -> 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
+    /** Already paired: the channel is open only to tell the car which phone this is. */
+    @Volatile private var announcing = 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 || announcing }?.service?.serviceId ?: -1
+
+    fun init(context: Context) {
+        appContext = context.applicationContext
+        _addressWanted.value = AppSettings.getString(context, KEY_ADDRESS_ASK, "").ifEmpty { null }
+    }
+
+    private val _addressWanted = MutableStateFlow<String?>(null)
+
+    /**
+     * A car paired over Bluetooth connected while Gearslip didn't know the phone's address: the
+     * car's name, for the phone's home screen to ask for it. Null when there's nothing to ask.
+     * Issue #18: a 2021 Bolt hung up 25 seconds in until it was told which phone this is.
+     */
+    val addressWanted: StateFlow<String?> = _addressWanted
+
+    /** Debug builds: shows the phone's card as if a car had just asked. */
+    fun askForAddressNow(context: Context) {
+        AppSettings.putString(context, KEY_ADDRESS_ASK, "Test car")
+        _addressWanted.value = "Test car"
+    }
+
+    /** The phone's card was answered or turned away: it doesn't come back for this car. */
+    fun addressAsked(context: Context) {
+        AppSettings.putString(context, KEY_ADDRESS_ASK, "")
+        _addressWanted.value = null
+    }
+
+    /**
+     * Once per car: it waits on the phone, and the car screen says so once. A car that keeps its
+     * screen isn't asked again on every drive: plenty of cars just wait for a tap on their icon.
+     */
+    @SuppressLint("MissingPermission")
+    private fun askForAddress(device: BluetoothDevice, carAddress: String) {
+        val context = appContext ?: return
+        val asked = AppSettings.getString(context, KEY_ADDRESS_ASKED, "").split(",").filter { it.isNotEmpty() }
+        if (hash(carAddress) in asked) return
+        AppSettings.putString(context, KEY_ADDRESS_ASKED, (asked + hash(carAddress)).distinct().joinToString(","))
+        val name = runCatching { device.alias ?: device.name }.getOrNull()?.takeIf { it.isNotBlank() }
+            ?: context.getString(R.string.bt_address_your_car)
+        AppSettings.putString(context, KEY_ADDRESS_ASK, name)
+        _addressWanted.value = name
+        log.i("paired, but the phone's address isn't known: asking on the phone")
+        main.post { CarToasts.show(this, context.getString(R.string.bt_address_car_note), CarToast.LENGTH_LONG) }
+    }
+
+    /**
+     * Called once the car lists its services. Asks on the car screen only if there's pairing to do.
+     * [answered] runs when the car answers a pairing request or the pairing finishes.
+     */
+    fun onCarConnected(
+        service: ServiceDiscovery.BluetoothService,
+        open: () -> Unit,
+        send: (messageId: Int, body: ByteArray) -> Unit,
+        answered: () -> Unit = {},
+    ) {
+        car = Car(service, open, send, answered)
+        bondStarted = false
+        announcing = false
+        log.i("the car offers Bluetooth pairing, methods=${service.pairingMethods}")
+        val device = device() ?: return
+        when {
+            device.bondState == BluetoothDevice.BOND_BONDED && typedAddress() != null -> {
+                log.i("already paired with this car - telling it which phone this is")
+                announcing = true
+                open()
+            }
+            device.bondState == BluetoothDevice.BOND_BONDED -> {
+                log.i("already paired with this car")
+                askForAddress(device, service.carAddress)
+            }
+            declined(service.carAddress) -> log.i("not paired, and the driver said not now for this car")
+            else -> _prompt.value = Prompt.ASK
+        }
+    }
+
+    /**
+     * Opens the car's Bluetooth channel though there's no pairing to do, as a real phone does on
+     * every connection. Issue #18: a 2021 Bolt hangs up about 20 seconds in, and this is one of
+     * the two channels it offers that Gearslip never opened. Without an address the driver typed,
+     * it only opens the channel: a made-up address could set the car pairing with the wrong phone.
+     */
+    fun announce(why: String) {
+        val c = car ?: return
+        if (pairing || announcing) return
+        announcing = true
+        log.i("-> ChannelOpenRequest on channel ${c.service.serviceId} ($why)")
+        c.open()
+    }
+
+    /**
+     * The car is keeping its own screen: do what Android Auto does on every connection, and tell
+     * it over Bluetooth which phone this is. Every Honda on file keeps its screen (a 2017 Pilot, a
+     * 2017 and a 2020 Civic; issues #43 and #57), and in each log the car's Bluetooth channel was
+     * never opened. Honda starts Android Auto with what its manuals call auto pairing, which runs
+     * on that channel, and a 2021 Bolt kept hanging up until it heard the phone's address (#18).
+     *
+     * - Paired, with the address typed in: the car already heard it at connect.
+     * - Paired, no address: open the channel, and ask for the address on the phone again.
+     * - Not paired: the Pair card waits on the car's screen, which this car won't give up, so
+     *   pair as if the driver had tapped it. Android's pairing dialog still asks on the phone.
+     *
+     * True when the car was sent something it may answer.
+     */
+    fun onScreenWithheld(): Boolean {
+        val c = car ?: return false
+        if (pairing || announcing) return false
+        val device = device() ?: return false
+        return when {
+            device.bondState == BluetoothDevice.BOND_BONDED -> {
+                askForAddress(device, c.service.carAddress)
+                announce("the car is keeping its screen")
+                true
+            }
+            device.bondState != BluetoothDevice.BOND_NONE -> false
+            declined(c.service.carAddress) -> false
+            else -> {
+                log.i("the car is keeping its screen and isn't paired with this phone - pairing, as Android Auto does")
+                main.post { pair() }
+                true
+            }
+        }
+    }
+
+    fun onCarDisconnected() {
+        car = null
+        pairing = false
+        announcing = 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 ${c.service.serviceId}")
+        // If the car never answers on its channel, pair from the phone anyway.
+        main.postDelayed({ startBond("the car didn't answer the pairing request") }, CAR_REPLY_WAIT_MS)
+        main.postDelayed({
+            if (pairing) finish(R.string.bt_pair_unfinished)
+        }, GIVE_UP_MS)
+    }
+
+    /** The driver tapped Not now: this car isn't asked about again. */
+    fun notNow() {
+        car?.service?.carAddress?.let { address ->
+            val context = appContext ?: return@let
+            val list = AppSettings.getString(context, KEY_DECLINED, "").split(",").filter { it.isNotEmpty() }
+            AppSettings.putString(context, KEY_DECLINED, (list + hash(address)).distinct().joinToString(","))
+        }
+        _prompt.value = Prompt.NONE
+    }
+
+    /** Hides the pairing card. The phone's own dialog carries on. */
+    fun hide() {
+        _prompt.value = Prompt.NONE
+    }
+
+    fun onMessage(messageId: Int, body: ByteArray) {
+        val c = car ?: return
+        when (messageId) {
+            MSG_CHANNEL_OPEN_RESPONSE -> {
+                val status = Protobuf.readInt32Field(body, 1) ?: 0
+                log.i("<- ChannelOpenResponse: status=$status")
+                if (status != 0) {
+                    if (announcing) log.i("the car wouldn't open its Bluetooth channel")
+                    else main.post { startBond("the car wouldn't open its Bluetooth channel") }
+                    return
+                }
+                if (announcing && typedAddress() == null) {
+                    log.i("Bluetooth channel open; no address typed in Settings, so no PairingRequest")
+                    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=${Wire.varint(fields, 2) == 1L}")
+                c.answered()
+                if (!pairing) return
+                // Some cars start pairing themselves once they answer; give them a moment first.
+                main.postDelayed({ startBond("the car answered") }, CAR_BOND_WAIT_MS)
+            }
+            // Carries the pairing code. Android shows it to the driver, so it stays out of the log.
+            MSG_AUTHENTICATION_DATA -> log.i("<- AuthenticationData (${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(R.string.bt_pair_not_started)
+    }
+
+    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(R.string.bt_paired)
+                        car?.answered?.invoke()
+                    }
+                    previous == BluetoothDevice.BOND_BONDING -> finish(R.string.bt_pair_unfinished)
+                }
+            }
+        }
+        context.registerReceiver(r, IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED), Context.RECEIVER_EXPORTED)
+        receiver = r
+    }
+
+    private fun finish(@StringRes message: Int) {
+        pairing = false
+        stopWatching()
+        main.removeCallbacksAndMessages(null)
+        _prompt.value = Prompt.NONE
+        CarToasts.show(this, appContext?.getString(message) ?: return, 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 ?: run {
+            log.w("can't check pairing: Bluetooth isn't set up yet")
+            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, so the one the driver typed in wins.
+     * Sent either way, as the field is required. Never logged: it identifies the phone.
+     */
+    @SuppressLint("MissingPermission", "HardwareIds")
+    private fun phoneAddress(): String =
+        typedAddress()
+            ?: runCatching { appContext?.getSystemService(BluetoothManager::class.java)?.adapter?.address }.getOrNull()
+            ?: "02:00:00:00:00:00"
+
+    private fun typedAddress(): String? = appContext?.let { typedAddress(it) }
+
+    /** The phone's own address as the driver typed it in Settings, or null. */
+    fun typedAddress(context: Context): String? =
+        AppSettings.getString(context, KEY_PHONE_ADDRESS, "").takeIf { BluetoothAdapter.checkBluetoothAddress(it) }
+
+    /** Saves [address] after tidying it up; false when it isn't one. Empty clears it. */
+    fun setTypedAddress(context: Context, address: String): Boolean {
+        val tidy = address.trim().uppercase().replace('-', ':')
+        if (tidy.isNotEmpty() && !BluetoothAdapter.checkBluetoothAddress(tidy)) return false
+        AppSettings.putString(context, KEY_PHONE_ADDRESS, tidy)
+        if (tidy.isNotEmpty()) addressAsked(context)
+        return true
+    }
+
+    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"
+    /** The car's name while the phone's card asks for the address; empty when it doesn't. */
+    private const val KEY_ADDRESS_ASK = "bluetooth_address_ask"
+    /** Hashes of the cars already asked about, so each asks once. */
+    private const val KEY_ADDRESS_ASKED = "bluetooth_address_asked"
+    private const val KEY_PHONE_ADDRESS = "phone_bluetooth_address"
+    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

@@ -1,5 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.ui.res.stringResource
+import app.seb3thehacker.gearslip.R
 import android.Manifest
 import android.content.Context
 import android.content.pm.PackageManager
@@ -12,6 +14,10 @@ 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.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.MaterialTheme
@@ -60,7 +66,7 @@ fun CarDashboardScreen() {
             .padding(horizontal = 24.dp, vertical = 16.dp),
         verticalArrangement = Arrangement.spacedBy(24.dp),
     ) {
-        ScreenHeader("Today")
+        ScreenHeader(stringResource(R.string.dash_today))
         WeatherCard(context)
         AgendaCard(context)
         NotificationsSection()
@@ -84,27 +90,74 @@ private fun WeatherCard(context: Context) {
             horizontalArrangement = Arrangement.spacedBy(16.dp),
         ) {
             when (val s = state) {
-                WeatherState.Loading -> Text("Getting weather…", style = MaterialTheme.typography.bodyLarge)
+                WeatherState.Loading -> Text(stringResource(R.string.dash_getting_weather), style = MaterialTheme.typography.bodyLarge)
                 is WeatherState.Unavailable -> Text(
-                    s.reason, style = MaterialTheme.typography.bodyLarge,
+                    stringResource(s.reason), style = MaterialTheme.typography.bodyLarge,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
                 is WeatherState.Ready -> {
                     val w = s.data
                     WeatherIcon(w.code, w.isDay, size = 44.dp)
-                    Column {
+                    Column(Modifier.weight(1f)) {
                         Text(
-                            "${w.temp}${w.tempUnit}  ·  ${Weather.describe(w.code)}",
+                            "${w.temp}${w.tempUnit}  ·  ${Weather.condition(w.code)}",
                             style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.SemiBold,
+                            maxLines = 1, overflow = androidx.compose.ui.text.style.TextOverflow.Ellipsis,
                         )
-                        Text(w.place, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                        Text(w.place, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1)
                     }
+                    NextHours(w.hours, Modifier.weight(1.3f))
                 }
             }
         }
     }
 }
 
+/**
+ * The next few hours beside the weather now, in the same card, so a glance answers "will it rain
+ * on the way" without opening Weather. As many as fit, up to five; none if fewer than three would.
+ */
+@Composable
+private fun NextHours(all: List<HourForecast>, modifier: Modifier) {
+    val now = System.currentTimeMillis()
+    // The forecast is cached, so its first hours may already be past.
+    val hours = all.filter { it.time > now }
+    androidx.compose.foundation.layout.BoxWithConstraints(modifier) {
+        val fit = (maxWidth / HOUR_WIDTH).toInt().coerceAtMost(5)
+        if (fit < 3 || hours.size < 3) return@BoxWithConstraints
+        Row(Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
+            Box(Modifier.width(1.dp).height(64.dp).background(MaterialTheme.colorScheme.outlineVariant))
+            hours.take(fit).forEach { h ->
+                Column(
+                    Modifier.weight(1f),
+                    horizontalAlignment = Alignment.CenterHorizontally,
+                    verticalArrangement = Arrangement.spacedBy(2.dp),
+                ) {
+                    Text(
+                        DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(h.time)).replace(":00", ""),
+                        style = MaterialTheme.typography.labelMedium,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        maxLines = 1,
+                    )
+                    WeatherIcon(h.code, h.isDay, size = 24.dp)
+                    Text("${h.temp}°", style = MaterialTheme.typography.titleSmall, fontWeight = FontWeight.SemiBold)
+                    // Kept as a blank line when dry, so every column lines up.
+                    Text(
+                        if (h.rainChance >= RAIN_SHOWN) "${h.rainChance}%" else " ",
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.primary,
+                    )
+                }
+            }
+        }
+    }
+}
+
+private val HOUR_WIDTH = 64.dp
+
+/** Below this a chance of rain is noise on a glance card; the Weather screen still shows it. */
+private const val RAIN_SHOWN = 20
+
 @Composable
 private fun AgendaCard(context: Context) {
     val events by produceState<List<AgendaEvent>?>(cachedAgenda) {
@@ -112,12 +165,12 @@ private fun AgendaCard(context: Context) {
     }
 
     Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
-        Text("Coming up", style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
+        Text(stringResource(R.string.dash_coming_up), style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
         val list = events
         when {
-            list == null -> Text("Loading calendar…", style = MaterialTheme.typography.bodyMedium)
+            list == null -> Text(stringResource(R.string.dash_loading_calendar), style = MaterialTheme.typography.bodyMedium)
             list.isEmpty() -> Text(
-                "Nothing in the next week.",
+                stringResource(R.string.dash_nothing_week),
                 style = MaterialTheme.typography.bodyMedium,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
             )
@@ -135,7 +188,7 @@ private fun EventRow(event: AgendaEvent) {
             verticalAlignment = Alignment.CenterVertically,
         ) {
             Text(
-                eventWhen(event),
+                eventWhen(event, stringResource(R.string.dash_all_day)),
                 style = MaterialTheme.typography.bodyLarge,
                 fontWeight = FontWeight.SemiBold,
             )
@@ -149,14 +202,14 @@ private fun EventRow(event: AgendaEvent) {
     }
 }
 
-/** "Today" events show just a time; later days get a weekday so a week's list stays readable. */
-private fun eventWhen(event: AgendaEvent): String {
+/** stringResource(R.string.dash_today) events show just a time; later days get a weekday so a week's list stays readable. */
+private fun eventWhen(event: AgendaEvent, allDay: String): String {
     val zone = if (event.allDay) TimeZone.getTimeZone("UTC") else TimeZone.getDefault()
     val start = Calendar.getInstance(zone).apply { timeInMillis = event.startMillis }
     val today = Calendar.getInstance()
     val sameDay = start.get(Calendar.YEAR) == today.get(Calendar.YEAR) &&
         start.get(Calendar.DAY_OF_YEAR) == today.get(Calendar.DAY_OF_YEAR)
-    val time = if (event.allDay) "All day" else DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(event.startMillis))
+    val time = if (event.allDay) allDay else DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(event.startMillis))
     if (sameDay || (event.allDay && start.before(today))) return time
     return SimpleDateFormat("EEE", Locale.getDefault()).apply { timeZone = zone }.format(Date(event.startMillis)) + " " + time
 }

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

@@ -0,0 +1,110 @@
+package app.seb3thehacker.gearslip.car
+
+import app.seb3thehacker.gearslip.Wire
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * The car's sensors, read into real values for the car apps that ask (a map's speed, an EV app's
+ * range). [CarSensors] keeps the raw readings for the Vehicle data screen; this keeps the few with
+ * a known meaning, decoded the way Android Auto's SensorBatch scales them:
+ *
+ *   gps_location = 1 { latitude_e7 = 2; longitude_e7 = 3; accuracy_e3 = 4; altitude_e2 = 5;
+ *                      speed_e3 = 6; bearing_e6 = 7 }
+ *   compass = 2 { bearing_e6 = 1 }      speed = 3 { speed_e3 = 1 }  (metres per second)
+ *   odometer = 5 { kms_e1 = 1 }         fuel = 6 { level = 1 (percent); range = 2 (km); low = 3 }
+ *
+ * Each value is null until the car first sends it, and the whole lot clears when it disconnects.
+ */
+object CarData {
+
+    class Location(
+        val latitude: Double,
+        val longitude: Double,
+        val accuracyMeters: Float?,
+        val altitudeMeters: Double?,
+        val speedMps: Float?,
+        val bearingDegrees: Float?,
+    )
+
+    data class Snapshot(
+        val speedMps: Float? = null,
+        val odometerKm: Float? = null,
+        val fuelPercent: Int? = null,
+        val rangeKm: Int? = null,
+        val fuelLow: Boolean? = null,
+        val compassDegrees: Float? = null,
+        val location: Location? = null,
+        /** When each kind last changed, by its SensorBatch field number. */
+        val updatedAt: Map<Int, Long> = emptyMap(),
+    )
+
+    /** What the car says it is, from its service discovery: model and year. It names no maker. */
+    class Model(val name: String, val year: Int?)
+
+    private val flow = MutableStateFlow(Snapshot())
+    val state: StateFlow<Snapshot> = flow
+
+    @Volatile var model: Model? = null
+        private set
+
+    fun onModel(name: String, year: String) {
+        model = name.takeIf { it.isNotBlank() }?.let { Model(it, year.toIntOrNull()?.takeIf { y -> y > 0 }) }
+    }
+
+    fun onEvent(body: ByteArray) {
+        val now = System.currentTimeMillis()
+        val batch = Wire.fields(body)
+        var s = flow.value
+        val touched = HashSet<Int>()
+        // Each kind may come several times in one batch: the last is the newest.
+        Wire.allBytes(batch, LOCATION).lastOrNull()?.let { bytes ->
+            val f = Wire.fields(bytes)
+            val lat = Wire.varint(f, 2)?.toInt()
+            val lon = Wire.varint(f, 3)?.toInt()
+            if (lat != null && lon != null) {
+                s = s.copy(
+                    location = Location(
+                        lat / 1e7, lon / 1e7,
+                        Wire.varint(f, 4)?.let { it / 1e3f },
+                        Wire.varint(f, 5)?.let { it.toInt() / 1e2 },
+                        Wire.varint(f, 6)?.let { it.toInt() / 1e3f },
+                        Wire.varint(f, 7)?.let { it.toInt() / 1e6f },
+                    ),
+                )
+                touched += LOCATION
+            }
+        }
+        Wire.allBytes(batch, COMPASS).lastOrNull()?.let { bytes ->
+            Wire.varint(Wire.fields(bytes), 1)?.let { s = s.copy(compassDegrees = it.toInt() / 1e6f); touched += COMPASS }
+        }
+        Wire.allBytes(batch, SPEED).lastOrNull()?.let { bytes ->
+            Wire.varint(Wire.fields(bytes), 1)?.let { s = s.copy(speedMps = it.toInt() / 1e3f); touched += SPEED }
+        }
+        Wire.allBytes(batch, ODOMETER).lastOrNull()?.let { bytes ->
+            Wire.varint(Wire.fields(bytes), 1)?.let { s = s.copy(odometerKm = it.toInt() / 10f); touched += ODOMETER }
+        }
+        Wire.allBytes(batch, FUEL).lastOrNull()?.let { bytes ->
+            val f = Wire.fields(bytes)
+            s = s.copy(
+                fuelPercent = Wire.varint(f, 1)?.toInt() ?: s.fuelPercent,
+                rangeKm = Wire.varint(f, 2)?.toInt() ?: s.rangeKm,
+                fuelLow = Wire.varint(f, 3)?.let { it != 0L } ?: s.fuelLow,
+            )
+            touched += FUEL
+        }
+        if (touched.isEmpty()) return
+        flow.value = s.copy(updatedAt = s.updatedAt + touched.associateWith { now })
+    }
+
+    fun clear() {
+        flow.value = Snapshot()
+        model = null
+    }
+
+    const val LOCATION = 1
+    const val COMPASS = 2
+    const val SPEED = 3
+    const val ODOMETER = 5
+    const val FUEL = 6
+}

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

@@ -37,6 +37,9 @@ object CarEnvironment {
     private val frameFlow = MutableStateFlow(Frame(800, 480, 160))
     val frame: StateFlow<Frame> = frameFlow
 
+    /** The density the car reported; [frame] carries the one the car UI and its apps draw at. */
+    private var carDensityDpi = 160
+
     val phoneDark: StateFlow<Boolean> = phoneDarkFlow
     val darkOutside: StateFlow<Boolean> = darkOutsideFlow
     val battery: StateFlow<Battery> = batteryFlow
@@ -64,7 +67,9 @@ object CarEnvironment {
     }
 
     @Volatile private var sensorNight: Boolean? = null
-    private var appContext: Context? = null
+    /** Set once the car UI starts; the cluster screen draws with it too. */
+    var appContext: Context? = null
+        private set
     private var running = false
 
     private val handler = Handler(Looper.getMainLooper())
@@ -93,8 +98,18 @@ object CarEnvironment {
     }
 
     fun setDisplay(width: Int, height: Int, densityDpi: Int) {
-        displayFlow.value = "${width}x$height @ ${densityDpi}dpi"
-        frameFlow.value = Frame(width, height, densityDpi)
+        carDensityDpi = densityDpi
+        val dpi = CarSettings.effectiveDensity(densityDpi)
+        displayFlow.value = "${width}x$height @ ${dpi}dpi"
+        frameFlow.value = Frame(width, height, dpi)
+    }
+
+    /**
+     * Takes up the density setting. It's read only as a session starts, so the display and the
+     * apps on it can't disagree mid-drive; a session with no car behind it, the preview, asks here.
+     */
+    fun applyDensity() {
+        frameFlow.value = frameFlow.value.copy(densityDpi = CarSettings.effectiveDensity(carDensityDpi))
     }
 
     fun start(context: Context) {

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

@@ -0,0 +1,51 @@
+package app.seb3thehacker.gearslip.car
+
+import android.os.SystemClock
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+
+/**
+ * Full screen for the screen that asks for it (the browser, or a video in it): no header and no
+ * nav bar. A swipe in from the top or bottom edge brings the nav bar back for a few seconds,
+ * with a button to leave full screen; [revealed] says when.
+ */
+object CarFullscreen {
+
+    var active by mutableStateOf(false)
+        private set
+
+    var revealed by mutableStateOf(false)
+        private set
+
+    private var lastTouch = 0L
+
+    fun enter() {
+        active = true
+        revealed = false
+    }
+
+    fun exit() {
+        active = false
+        revealed = false
+    }
+
+    /** A swipe in from an edge: show the nav bar and the way out. */
+    fun reveal() {
+        if (!active) return
+        lastTouch = SystemClock.uptimeMillis()
+        revealed = true
+    }
+
+    /** Any touch keeps a revealed bar up, so it doesn't slide away under a finger reaching for it. */
+    fun touch() {
+        if (revealed) lastTouch = SystemClock.uptimeMillis()
+    }
+
+    /** Called on a timer; hides the bar again after [REVEAL_MS] without a touch. */
+    fun tick() {
+        if (revealed && SystemClock.uptimeMillis() - lastTouch >= REVEAL_MS) revealed = false
+    }
+
+    private const val REVEAL_MS = 4_000L
+}

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

@@ -1,5 +1,6 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.ui.res.stringResource
 import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -12,6 +13,8 @@ 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 app.seb3thehacker.gearslip.car.theme.gsPanelShadow
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.PlayArrow
@@ -64,7 +67,9 @@ import app.seb3thehacker.gearslip.media.NowPlaying
 import kotlinx.coroutines.launch
 
 /**
- * The home screen: the map on the left, the docked player on the right when asked for.
+ * The home screen: the map, with the docked player floating over one side of it when asked for.
+ * With the player on the left, the map app's cards move to the map's far edge, so the player, the
+ * map and the cards each keep their own space.
  *
  * 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
@@ -93,27 +98,57 @@ fun CarHome() {
         if (onHome) seenHome[0] = true
     }
     val splitScreen = phase == CarMedia.Phase.READY && now.isActive && panel != SidePanel.NONE
+    val playerLeft by CarSettings.playerLeft.collectAsStateWithLifecycle()
+    // What the card showed last, so it still has something to show while it slides away.
+    val shown = remember { androidx.compose.runtime.mutableStateOf(SidePanel.CONTROLS) }
+    if (panel != SidePanel.NONE) shown.value = panel
 
-    // 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 (splitScreen) 2.1f else 1f)
-                .fillMaxHeight(),
+    // The map runs edge to edge underneath; the player floats over one side of it as a card, with
+    // a gap all round. The map's surface keeps its size when the card comes and goes, so the app
+    // only re-centres its map instead of drawing onto a new surface.
+    BoxWithConstraints(Modifier.fillMaxSize()) {
+        val column = (maxWidth / PLAYER_SHARE).coerceIn(PLAYER_MIN_WIDTH, PLAYER_MAX_WIDTH)
+        androidx.compose.runtime.CompositionLocalProvider(
+            LocalCardsAtEnd provides (splitScreen && playerLeft),
+            LocalSidePanelInset provides if (splitScreen) column else 0.dp,
         ) {
             MapPane(navStatus, frame)
         }
-        if (splitScreen) {
-            val side = Modifier.weight(1f).fillMaxHeight()
-            if (panel == SidePanel.LYRICS) SideLyrics(now, side) else DockedPlayer(now, side)
+        androidx.compose.animation.AnimatedVisibility(
+            splitScreen,
+            Modifier.align(if (playerLeft) Alignment.CenterStart else Alignment.CenterEnd),
+            enter = androidx.compose.animation.slideInHorizontally(tween(220)) { if (playerLeft) -it / 3 else it / 3 } +
+                androidx.compose.animation.fadeIn(tween(180)),
+            exit = androidx.compose.animation.slideOutHorizontally(tween(180)) { if (playerLeft) -it / 3 else it / 3 } +
+                androidx.compose.animation.fadeOut(tween(140)),
+        ) {
+            val card = Modifier
+                .width(column)
+                .fillMaxHeight()
+                .padding(
+                    start = if (playerLeft) CARD_GAP else 0.dp,
+                    end = if (playerLeft) 0.dp else CARD_GAP,
+                    top = CARD_GAP,
+                    bottom = LocalNavBarInset.current + CARD_GAP,
+                )
+            if (shown.value == SidePanel.LYRICS) SideLyrics(now, card) else DockedPlayer(now, card)
         }
     }
 }
 
+/** The player takes one part in this many of the screen's width. */
+private const val PLAYER_SHARE = 3.6f
+
+/** Narrow enough to leave the map most of a small screen; on a wide one the map gets the extra room. */
+private val PLAYER_MIN_WIDTH = 240.dp
+private val PLAYER_MAX_WIDTH = 340.dp
+
+/** Between the player card and the screen's edges, and the map's own cards beside it. */
+private val CARD_GAP = 12.dp
+
+/** The card's corners: rounder than a button's, as the map app's own cards are. */
+private val CARD_SHAPE = RoundedCornerShape(24.dp)
+
 @Composable
 private fun MapPane(status: CarAppConnection.Status, frame: CarEnvironment.Frame) {
     val navigator = LocalCarNavigator.current
@@ -123,8 +158,11 @@ private fun MapPane(status: CarAppConnection.Status, frame: CarEnvironment.Frame
     }
 
     Column(
-        Modifier.fillMaxSize().padding(24.dp),
-        verticalArrangement = Arrangement.Center,
+        Modifier.fillMaxSize().padding(
+            start = if (LocalCardsAtEnd.current) LocalSidePanelInset.current else 0.dp,
+            end = if (LocalCardsAtEnd.current) 0.dp else LocalSidePanelInset.current,
+        ).padding(24.dp),
+        verticalArrangement = Arrangement.spacedBy(10.dp, Alignment.CenterVertically),
         horizontalAlignment = Alignment.CenterHorizontally,
     ) {
         val hasLast = CarSettings.lastNav.value != null
@@ -132,18 +170,19 @@ private fun MapPane(status: CarAppConnection.Status, frame: CarEnvironment.Frame
         val scope = androidx.compose.runtime.rememberCoroutineScope()
         when (status.phase) {
             CarAppConnection.Phase.BINDING, CarAppConnection.Phase.HANDSHAKE ->
-                Text("Starting ${status.app ?: "the map"}…", style = MaterialTheme.typography.titleMedium)
+                Text(status.app?.let { stringResource(R.string.home_starting, it) } ?: stringResource(R.string.home_starting_map), style = MaterialTheme.typography.titleMedium)
             CarAppConnection.Phase.REJECTED, CarAppConnection.Phase.FAILED -> {
-                Text("${status.app ?: "The map app"} would not start.", style = MaterialTheme.typography.titleMedium)
+                Text(status.app?.let { stringResource(R.string.home_failed, it) } ?: stringResource(R.string.home_failed_map), style = MaterialTheme.typography.titleMedium)
                 status.detail?.let { Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant) }
-                GsButton(onClick = navigator::apps, tone = GsTone.Tonal) { Text("Choose another app") }
+                Spacer(Modifier.height(8.dp))
+                StatusButton(stringResource(R.string.home_choose_app), GsTone.Primary, navigator::apps)
             }
             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(stringResource(R.string.home_no_maps), style = MaterialTheme.typography.titleMedium)
                 Text(
-                    "Install a navigation app that supports Android Auto and it will start here on its own.",
+                    stringResource(R.string.home_no_maps_body),
                     style = MaterialTheme.typography.bodyMedium,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
@@ -151,9 +190,18 @@ private fun MapPane(status: CarAppConnection.Status, frame: CarEnvironment.Frame
                 // 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") }
+                Text(stringResource(R.string.home_map_stopped), style = MaterialTheme.typography.headlineSmall, fontWeight = FontWeight.Bold)
+                Text(
+                    stringResource(R.string.home_map_stopped_body),
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                Spacer(Modifier.height(8.dp))
+                // Side by side, the same size, the likely one lit: one clear choice, not a stack.
+                Row(horizontalArrangement = Arrangement.spacedBy(14.dp)) {
+                    StatusButton(stringResource(R.string.home_reopen_map), GsTone.Primary) { scope.launch { CarServices.reconnectNav(frame) } }
+                    StatusButton(stringResource(R.string.home_car_apps), GsTone.Tonal) { navigator.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.
@@ -162,9 +210,17 @@ private fun MapPane(status: CarAppConnection.Status, frame: CarEnvironment.Frame
     }
 }
 
+/** A big, even button for the map pane's few choices. */
+@Composable
+private fun StatusButton(label: String, tone: GsTone, onClick: () -> Unit) {
+    GsButton(onClick = onClick, tone = tone, modifier = Modifier.width(220.dp).height(64.dp)) {
+        Text(label, style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+    }
+}
+
 /**
- * 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
+ * The player, docked beside the map: the art as large as it fits, then title, progress, transport,
+ * and like, shuffle, repeat and lyrics along the bottom. 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
@@ -175,28 +231,31 @@ private fun DockedPlayer(now: NowPlaying, modifier: Modifier) {
     val scheme = MaterialTheme.colorScheme
     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)) {
-        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)
+    // The theme's surface, with a faint wash of the cover's colours behind the top of it. A solid
+    // slab of album colour beside the map fought it for attention; this only hints at the song.
+    Surface(modifier = modifier.gsPanelShadow(CARD_SHAPE), shape = CARD_SHAPE, color = scheme.surfaceContainer) {
+        AlbumGlow(art, Modifier.fillMaxSize())
+        Box(Modifier.fillMaxSize().padding(12.dp)) {
             Column(Modifier.fillMaxSize(), horizontalAlignment = Alignment.CenterHorizontally) {
-                Box(Modifier.fillMaxWidth()) {
+                // The cover gets everything the controls leave, as big a square as fits, sitting
+                // right on top of the title; the controls stay pinned to the bottom.
+                BoxWithConstraints(Modifier.weight(1f).fillMaxWidth(), contentAlignment = Alignment.BottomCenter) {
+                    val artSize = minOf(maxWidth, maxHeight).coerceAtLeast(0.dp)
                     // Art opens the full media screen, same as on the pill.
+                    val coverShape = RoundedCornerShape(16.dp)
                     Box(
                         Modifier
-                            .align(Alignment.TopCenter)
                             .size(artSize)
-                            .clip(RoundedCornerShape(12.dp))
+                            .gsPanelShadow(coverShape)
+                            .clip(coverShape)
                             .background(scheme.surface)
                             .clickable { navigator.media() },
                     ) {
-                        art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
+                        // A new song's cover fades in over the old one instead of cutting to it.
+                        androidx.compose.animation.Crossfade(art, animationSpec = tween(350), label = "cover") { shown ->
+                            shown?.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,
-                    )
                 }
                 Spacer(Modifier.height(10.dp))
                 Text(
@@ -212,46 +271,53 @@ private fun DockedPlayer(now: NowPlaying, modifier: Modifier) {
                 } else {
                     Spacer(Modifier.height(10.dp))
                 }
-                TransportRow(now, media, skip = 48.dp, modifier = Modifier.fillMaxWidth())
+                TransportRow(now, media, skip = 56.dp, modifier = Modifier.fillMaxWidth())
                 Spacer(Modifier.height(10.dp))
-                PlayModeRow(now, media, size = 42.dp, modifier = Modifier.fillMaxWidth()) {
+                PlayModeRow(now, media, size = 50.dp, modifier = Modifier.fillMaxWidth()) {
                     GsIconButton(
-                        ImageVector.vectorResource(R.drawable.lyrics_24), "Lyrics", navigator::showSideLyrics,
-                        size = 42.dp, iconSize = 22.dp,
+                        ImageVector.vectorResource(R.drawable.lyrics_24), stringResource(R.string.storage_lyrics), navigator::showSideLyrics,
+                        size = 50.dp, iconSize = 26.dp,
                     )
                 }
             }
+            GsIconButton(
+                Icons.Filled.Close, stringResource(R.string.home_back_nav), navigator::closeSidePanel,
+                Modifier.align(Alignment.TopEnd), size = 36.dp, iconSize = 20.dp,
+            )
         }
     }
 }
 
 /**
- * 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.
+ * Lyrics alone beside the map, big enough to read at a glance. The header is slim, since the
+ * player goes back to the nav bar meanwhile and names the song there. Its note button swaps the
+ * lyrics back for the player; the X closes the panel.
  */
 @Composable
 private fun SideLyrics(now: NowPlaying, modifier: Modifier) {
     val navigator = LocalCarNavigator.current
     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) }
-    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,
-                    )
+    Surface(modifier = modifier.gsPanelShadow(CARD_SHAPE), shape = CARD_SHAPE, color = scheme.surfaceContainer) {
+        Column(Modifier.fillMaxSize().padding(start = 18.dp, end = 12.dp, top = 12.dp, bottom = 8.dp)) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Box(Modifier.size(36.dp).clip(RoundedCornerShape(8.dp)).background(scheme.surface)) {
+                    art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
                 }
-                GsIconButton(Icons.Filled.Close, "Hide lyrics", navigator::closeSidePanel, size = 36.dp, iconSize = 20.dp)
+                Spacer(Modifier.size(10.dp))
+                Text(
+                    listOf(now.title, now.artist).filter { it.isNotEmpty() }.joinToString(" · "),
+                    Modifier.weight(1f),
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = scheme.onSurfaceVariant,
+                    maxLines = 1, overflow = TextOverflow.Ellipsis,
+                )
+                // The way back to the player, as the player's own Lyrics button is the way here.
+                GsIconButton(MediaIcons.MusicNote, stringResource(R.string.home_show_player), navigator::showSidePlayer, size = 36.dp, iconSize = 20.dp)
+                Spacer(Modifier.size(6.dp))
+                GsIconButton(Icons.Filled.Close, stringResource(R.string.home_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 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.ui.res.stringResource
+import app.seb3thehacker.gearslip.R
 import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
@@ -44,6 +46,12 @@ object CarKeyboardVisibility {
     val state = mutableStateOf(false)
 }
 
+/**
+ * True for the car UI the phone's own car preview draws. The phone is in hand there, so a
+ * [CarKeyboard] draws nothing and the phone's keyboard does the typing instead (see [PhoneTyping]).
+ */
+val LocalCarPreview = compositionLocalOf { false }
+
 /**
  * A keyboard the host draws itself.
  *
@@ -73,10 +81,11 @@ fun CarKeyboard(
 ) {
     var symbols by remember { mutableStateOf(false) }
     var shifted by remember { mutableStateOf(false) }
+    val preview = LocalCarPreview.current
 
-    DisposableEffect(Unit) {
-        CarKeyboardVisibility.state.value = true
-        onDispose { CarKeyboardVisibility.state.value = false }
+    DisposableEffect(preview) {
+        if (!preview) CarKeyboardVisibility.state.value = true
+        onDispose { if (!preview) CarKeyboardVisibility.state.value = false }
     }
 
     // The same field on the phone, for typing on its own keyboard: see [PhoneTyping].
@@ -88,6 +97,7 @@ fun CarKeyboard(
     }
     DisposableEffect(phoneField) { onDispose { PhoneTyping.close(phoneField) } }
     LaunchedEffect(text) { PhoneTyping.carText(phoneField, text) }
+    if (preview) return
 
     val rows = if (symbols) SYMBOL_ROWS else LETTER_ROWS
     val keyHeight = keyHeight(LocalConfiguration.current.screenHeightDp)
@@ -138,18 +148,18 @@ fun CarKeyboard(
                 }
 
                 // 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. Dismiss (when offered) is the
-                // last key, bottom-right corner of the keyboard.
+                // 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("$text ") }
-                    SubmitKey(Modifier.weight(1.6f), submitIcon, submitImage, onSubmit)
+                    Key(stringResource(R.string.keyboard_space), Modifier.weight(if (onDismiss != null) 3.2f else 4f)) { onTextChange("$text ") }
                     if (onDismiss != null) {
                         DismissKey(onDismiss, Modifier.weight(1.4f))
                     }
+                    SubmitKey(Modifier.weight(1.6f), submitIcon, submitImage, onSubmit)
                 }
             }
         }
@@ -192,7 +202,7 @@ private fun DismissKey(onClick: () -> Unit, modifier: Modifier = Modifier) {
             horizontalArrangement = Arrangement.Center,
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            Icon(Icons.Filled.Close, contentDescription = "Hide keyboard")
+            Icon(Icons.Filled.Close, contentDescription = stringResource(R.string.keyboard_hide))
         }
     }
 }
@@ -212,7 +222,7 @@ private fun SubmitKey(modifier: Modifier, search: Boolean, image: ImageVector?,
         ) {
             Icon(
                 image ?: if (search) Icons.Filled.Search else Icons.Filled.ArrowBack,
-                contentDescription = "Submit",
+                contentDescription = stringResource(R.string.keyboard_submit),
             )
         }
     }
@@ -222,9 +232,9 @@ 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
  * still fit. A 480-tall screen sets the floor; a taller one (LIVI's 1280x720) gets bigger keys.
  */
-private fun keyHeight(screenHeightDp: Int): Dp = (screenHeightDp * 0.075f).dp.coerceIn(36.dp, 52.dp)
+private fun keyHeight(screenHeightDp: Int): Dp = (screenHeightDp * 0.09f).dp.coerceIn(44.dp, 64.dp)
 
-private val LocalKeyHeight = compositionLocalOf { 36.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

@@ -27,14 +27,43 @@ object CarKeys {
     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
 
+    /** What a [KnobTaker] is offered: a turn of the knob, a focus key edge, or Back. */
+    sealed interface KnobEvent {
+        data class Turn(val steps: Int) : KnobEvent
+        data class Key(val keyCode: Int, val down: Boolean) : KnobEvent
+        data object Back : KnobEvent
+    }
+
+    /**
+     * Something on screen that wants the knob before focus moves: the full-screen map, which
+     * zooms and pans with it ([MapKnob]), and the app grid, which starts on the app opened last.
+     * Returns true for an event it kept. Called on the thread the keys arrive on, not the main one.
+     */
+    fun interface KnobTaker {
+        fun take(event: KnobEvent): Boolean
+    }
+
+    @Volatile var knobTaker: KnobTaker? = null
+
     private var appContext: Context? = null
     private val main = Handler(Looper.getMainLooper())
 
     fun init(context: Context) { appContext = context.applicationContext }
 
+    /** The keys that act on the media app. */
+    private val MEDIA_KEYS = setOf(
+        KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE, KeyEvent.KEYCODE_MEDIA_PLAY, KeyEvent.KEYCODE_MEDIA_PAUSE,
+        KeyEvent.KEYCODE_MEDIA_STOP, KeyEvent.KEYCODE_MEDIA_NEXT, KeyEvent.KEYCODE_MEDIA_PREVIOUS,
+    )
+
     /**
      * 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),
@@ -58,21 +87,30 @@ object CarKeys {
      */
     fun onKey(keyCode: Int, down: Boolean, longPress: Boolean): Boolean {
         if (keyCode in FOCUS_KEYS) {
+            if (knobTaker?.take(KnobEvent.Key(keyCode, down)) == true) return true
+            _focusMoves.tryEmit(Unit)
             focusSink?.invoke(keyCode, down)
             return true
         }
         if (!down) return keyCode in WANTED
-        val media = CarServices.media
+        // Null until the car shows Gearslip's screen. A 2020 Civic sends Play as soon as it hears
+        // the phone's Bluetooth address, while still on its own screen, and reaching for media
+        // then ended the session (issue #43).
+        val media = CarServices.mediaOrNull()
+        if (media == null && keyCode in MEDIA_KEYS) {
+            GearslipLog.i("keys: $keyCode before the car shows Gearslip - no media app to send it to yet")
+            return true
+        }
         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_MEDIA_PLAY_PAUSE -> media?.togglePlay()
+            KeyEvent.KEYCODE_MEDIA_PLAY -> if (media != null && !media.now.value.playing) media.togglePlay()
+            KeyEvent.KEYCODE_MEDIA_PAUSE, KeyEvent.KEYCODE_MEDIA_STOP -> if (media != null && 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_BACK -> if (knobTaker?.take(KnobEvent.Back) != true) screen(ScreenKey.BACK)
             KeyEvent.KEYCODE_HOME -> screen(ScreenKey.HOME)
             KEYCODE_NAVIGATION -> screen(ScreenKey.MAP)
             KEYCODE_MEDIA -> screen(ScreenKey.MEDIA)
@@ -86,6 +124,8 @@ object CarKeys {
     /** 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
+        if (knobTaker?.take(KnobEvent.Turn(delta)) == true) 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)
@@ -95,15 +135,10 @@ object CarKeys {
 
     /**
      * The voice key: answers the message on screen if there is one, otherwise starts the
-     * assistant when it's turned on.
+     * assistant.
      */
     private fun voice() = main.post {
-        if (VoiceReply.onVoiceKey()) return@post
-        if (CarSettings.experimentalFeaturesEnabled.value && CarSettings.voiceAssistantEnabled.value) {
-            CarAssistant.start()
-        } else {
-            GearslipLog.i("keys: voice pressed, but the assistant is off in settings")
-        }
+        if (!VoiceReply.onVoiceKey()) CarAssistant.start()
     }
 
     /** Answers a ringing call; with nothing ringing, opens the phone screen. */

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

@@ -1,5 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.ui.res.stringResource
+import app.seb3thehacker.gearslip.R
 import app.seb3thehacker.gearslip.car.theme.*
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.ExperimentalFoundationApi
@@ -14,6 +16,16 @@ 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.foundation.lazy.grid.itemsIndexed
+import androidx.compose.foundation.lazy.grid.rememberLazyGridState
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.rememberUpdatedState
+import androidx.compose.runtime.withFrameNanos
+import androidx.compose.ui.focus.FocusRequester
+import androidx.compose.ui.focus.focusRequester
+import app.seb3thehacker.gearslip.AppSettings
+import kotlinx.coroutines.launch
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Info
 import androidx.compose.material.icons.filled.KeyboardArrowDown
@@ -70,13 +82,11 @@ 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,
-    /** Starts and can be used, but rough enough not to call working; drawn with a yellow mark. */
-    val partial: Boolean = false,
     val onLongClick: (() -> Unit)? = null,
+    /** The entry's [Entry.componentId], for finding the app opened last. */
+    val id: String? = null,
     val onClick: () -> Unit,
 )
 
@@ -123,35 +133,66 @@ internal object LauncherCache {
             context.packageManager.getApplicationIcon(pkg).toBitmap(128, 128).asImageBitmap()
         }.getOrNull()
 
-        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 carApps = CarAppCatalog.installed(context).associateBy { it.component.packageName }
+        val mediaApps = MediaCatalog.installed(context).associateBy { it.component.packageName }
+        val messagingApps = MessagingCatalog.installed(context).associateBy { it.packageName }
 
-        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)
+        // One decision per app over everything it offers a car - a car screen, a player, car
+        // notifications - rather than a filter per kind that has to know about the others.
+        val tiles = (carApps.keys + mediaApps.keys + messagingApps.keys).flatMap { pkg ->
+            val icon by lazy { iconOf(pkg) }
+            tilesFor(carApps[pkg], mediaApps[pkg], messagingApps[pkg], context.getString(R.string.media_browse)).map { tile ->
+                when (tile) {
+                    is AppTile.Screen -> Entry(tile.label, icon, template = tile.app)
+                    is AppTile.Player -> Entry(tile.app.label, icon, media = tile.app)
+                    is AppTile.Messages -> Entry(tile.app.label, icon, messaging = tile.app)
+                }
             }
-        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 }
+        }
+        CarSettings.hideOnFirstSight(tiles.mapNotNull { entry ->
+            val pkg = (entry.template?.component ?: entry.media?.component)?.packageName ?: entry.messaging?.packageName
+            entry.componentId?.takeIf { pkg != null && KnownApps.startsHidden(context, pkg, entry.messaging != null) }
+        })
+        return tiles.sortedBy { it.label.lowercase() }.also { flow.value = it }
+    }
+}
+
+/** What one app gets on the launcher. */
+private sealed interface AppTile {
+    class Screen(val app: TemplateApp, val label: String) : AppTile
+    class Player(val app: app.seb3thehacker.gearslip.media.MediaApp) : AppTile
+    class Messages(val app: app.seb3thehacker.gearslip.notify.MessagingApp) : AppTile
+}
+
+/**
+ * The tiles for one app, from what it offers.
+ *
+ * - A car screen that is something other than media or messaging (RF Sentinel's POI screen) is
+ *   the app: its media service only makes sound, and its notifications are alerts, so it gets the
+ *   one tile under its own name.
+ * - A media app with both a car screen and a player (Spotify) gets both, the screen labelled
+ *   "· Browse", since they really are different screens - unless the screen is known to refuse
+ *   Gearslip while the player works, when the Browse tile would only report that.
+ * - A messenger's own car screen (Google Messages) won't start under Gearslip, and Gearslip's
+ *   Messages screen does the job, so it gets only that - and a messenger that is also a media
+ *   app keeps only its player.
+ */
+private fun tilesFor(
+    car: TemplateApp?,
+    media: app.seb3thehacker.gearslip.media.MediaApp?,
+    messaging: app.seb3thehacker.gearslip.notify.MessagingApp?,
+    browse: String,
+): List<AppTile> {
+    if (car != null && !car.isMediaScreen && car.kind != "messaging") return listOf(AppTile.Screen(car, car.label))
+    val pkg = car?.component?.packageName ?: media?.component?.packageName ?: messaging?.packageName ?: return emptyList()
+    return buildList {
+        val screenRefused = KnownApps.screenBroken(pkg) && KnownApps.playerWorks(pkg)
+        val messengerScreen = messaging != null && (car?.kind == "messaging" || car?.kind == "app")
+        if (car != null && !messengerScreen && !(media != null && screenRefused)) {
+            add(AppTile.Screen(car, if (media != null) "${car.label} · $browse" else car.label))
+        }
+        if (media != null) add(AppTile.Player(media))
+        else if (messaging != null) add(AppTile.Messages(messaging))
     }
 }
 
@@ -160,10 +201,13 @@ internal object LauncherCache {
 internal fun rememberAllEntries(): List<Entry> {
     val context = LocalContext.current
     val installed by LauncherCache.state.collectAsState()
+    val launcher by LauncherMode.active.collectAsState()
     LaunchedEffect(context) {
         if (LauncherCache.entries == null) withContext(Dispatchers.IO) { LauncherCache.load(context) }
     }
-    return remember(installed) { BuiltInApps.entries + installed.orEmpty() }
+    return remember(installed, launcher) {
+        BuiltInApps.entries(launcher, LauncherMode.canCall(context)) + installed.orEmpty()
+    }
 }
 
 /** The launcher's groups, in the order they're laid out. */
@@ -187,6 +231,8 @@ private fun groupOf(entry: Entry, mediaPackages: Set<String>): AppGroup {
     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
@@ -197,9 +243,10 @@ private fun groupOf(entry: Entry, mediaPackages: Set<String>): AppGroup {
  * 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.
+ * [hidden] leaves tiles out of the drawer only: a pinned app stays on the nav bar.
  */
-internal fun launcherOrder(all: List<Entry>, showVehicleData: Boolean, custom: List<String>): List<Entry> {
-    val shown = all.filter { it.builtIn !== BuiltInApps.VehicleData || showVehicleData }
+internal fun launcherOrder(all: List<Entry>, showVehicleData: Boolean, custom: List<String>, hidden: Set<String>): List<Entry> {
+    val shown = all.filter { (it.builtIn !== BuiltInApps.VehicleData || showVehicleData) && it.componentId !in hidden }
     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() }),
@@ -213,7 +260,7 @@ internal fun launcherOrder(all: List<Entry>, showVehicleData: Boolean, custom: L
 
 /** 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 }
+    BuiltInApps.everyEntry.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) }
@@ -241,6 +288,7 @@ internal fun launchEntry(entry: Entry, navigator: CarNavigator, frame: CarEnviro
 /** 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()
 
@@ -248,87 +296,63 @@ fun CarLauncher() {
     val all = rememberAllEntries()
     val running = rememberRunningApps()
     val showVehicleData = rememberVehicleDataShown()
-    var showBadgeKey by remember { mutableStateOf(false) }
 
     fun tileOf(entry: Entry): Tile {
-        // The badges rate an app's own car screens; a messenger shown on Gearslip's own Messages
-        // screen has none, so it gets no badge.
+        // 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,
-            verified = pkg != null && !KnownApps.isPartial(pkg) && (KnownApps.works(pkg) || (entry.media != null && KnownApps.playerWorks(pkg))),
-            broken = pkg != null && (KnownApps.isBroken(pkg) || (entry.template != null && KnownApps.screenBroken(pkg))),
-            partial = pkg != null && KnownApps.isPartial(pkg),
+            entry.builtIn?.let { context.getString(it.labelRes) } ?: entry.label, entry.icon, entry.builtIn?.glyph,
+            broken = pkg != null && (KnownApps.isBroken(context, pkg) || (entry.template != null && KnownApps.screenBroken(pkg))),
             onLongClick = id?.let { { navigator.showAppMenu(it) } },
-        ) { openApp(entry, id?.let { running[it] }, navigator, frame) }
+            id = id,
+        ) {
+            id?.let { AppSettings.putString(context, KEY_LAST_APP, it) }
+            openApp(entry, id?.let { running[it] }, navigator, frame)
+        }
     }
 
     val appOrder by CarSettings.appOrder.collectAsState()
-    val tiles = launcherOrder(all, showVehicleData, appOrder).map(::tileOf)
+    val hidden by CarSettings.hiddenApps.collectAsState()
+    val tiles = launcherOrder(all, showVehicleData, appOrder, hidden).map(::tileOf)
+
+    // With the knob, the first move on this screen lands on the app opened last rather than on
+    // the first button anywhere on screen (issue #74). After that the knob moves as usual, out to
+    // the nav bar and back; nudging up or down already jumps a row.
+    val gridState = rememberLazyGridState()
+    val scope = rememberCoroutineScope()
+    val lastFocus = remember { FocusRequester() }
+    val lastId = remember { AppSettings.getString(context, KEY_LAST_APP, "") }
+    val lastIndex = tiles.indexOfFirst { it.id == lastId }.coerceAtLeast(0)
+    val focusIndex by rememberUpdatedState(lastIndex)
+    DisposableEffect(Unit) {
+        var used = false
+        val taker = CarKeys.KnobTaker { event ->
+            if (used || event == CarKeys.KnobEvent.Back || (event is CarKeys.KnobEvent.Key && !event.down)) {
+                return@KnobTaker false
+            }
+            used = true
+            scope.launch {
+                gridState.scrollToItem(focusIndex)
+                withFrameNanos { }
+                runCatching { lastFocus.requestFocus() }
+            }
+            true
+        }
+        CarKeys.knobTaker = taker
+        onDispose { if (CarKeys.knobTaker === taker) CarKeys.knobTaker = null }
+    }
 
     LazyVerticalGrid(
         columns = GridCells.Adaptive(minSize = 108.dp),
+        state = gridState,
         modifier = Modifier.fillMaxSize(),
         contentPadding = PaddingValues(20.dp),
         horizontalArrangement = Arrangement.spacedBy(12.dp),
         verticalArrangement = Arrangement.spacedBy(12.dp),
     ) {
-        items(tiles) { AppTile(it) }
-        if (tiles.any { it.verified || it.broken || it.partial }) {
-            // Folded away behind one button: it's reference, read once, not something every
-            // visit to the launcher needs spelled out under the grid.
-            item(span = { GridItemSpan(maxLineSpan) }) {
-                Column(horizontalAlignment = Alignment.CenterHorizontally) {
-                    GsButton(onClick = { showBadgeKey = !showBadgeKey }, tone = GsTone.Neutral) {
-                        Icon(Icons.Filled.Info, contentDescription = null, modifier = Modifier.size(18.dp))
-                        Spacer(Modifier.width(8.dp))
-                        Text(if (showBadgeKey) "Hide badge key" else "What the badges mean")
-                    }
-                    if (showBadgeKey) {
-                        BadgeLegend(
-                            verified = tiles.any { it.verified },
-                            partial = tiles.any { it.partial },
-                            broken = tiles.any { it.broken },
-                        )
-                    }
-                }
-            }
-        }
-    }
-}
-
-/** Says what each badge on a tile means, once, under the grid - only the ones actually in use. */
-@Composable
-private fun BadgeLegend(verified: Boolean, partial: Boolean, broken: Boolean) {
-    Column(
-        Modifier.fillMaxWidth().padding(top = 4.dp),
-        horizontalAlignment = Alignment.CenterHorizontally,
-        verticalArrangement = Arrangement.spacedBy(4.dp),
-    ) {
-        if (verified) LegendRow(size = 16.dp, badge = { VerifiedBadge(it) }, text = "Tested and working with Gearslip")
-        if (partial) LegendRow(size = 16.dp, badge = { PartialBadge(it) }, text = "Runs, but not cleanly, with Gearslip")
-        if (broken) LegendRow(size = 16.dp, badge = { BrokenBadge(it) }, text = "Doesn't work with Gearslip yet")
-    }
-}
-
-@Composable
-private fun LegendRow(size: androidx.compose.ui.unit.Dp, badge: @Composable (androidx.compose.ui.unit.Dp) -> Unit, text: String) {
-    Row(horizontalArrangement = Arrangement.Center, verticalAlignment = Alignment.CenterVertically) {
-        badge(size)
-        Spacer(Modifier.width(8.dp))
-        Text(text, 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) {
-    Box(
-        modifier.size(size).background(Color(0xFF43A047), CircleShape),
-        contentAlignment = Alignment.Center,
-    ) {
-        Icon(Icons.Filled.Check, contentDescription = "Tested and working", tint = Color.White, modifier = Modifier.size(size * 0.66f))
+        itemsIndexed(tiles) { i, tile -> AppTile(tile, if (i == lastIndex) Modifier.focusRequester(lastFocus) else Modifier) }
     }
 }
 
@@ -339,43 +363,20 @@ private fun BrokenBadge(size: androidx.compose.ui.unit.Dp, modifier: Modifier =
         modifier.size(size).background(Color(0xFFD32F2F), CircleShape),
         contentAlignment = Alignment.Center,
     ) {
-        Icon(Icons.Filled.Close, contentDescription = "Doesn't work with Gearslip", tint = Color.White, modifier = Modifier.size(size * 0.66f))
+        Icon(Icons.Filled.Close, contentDescription = stringResource(R.string.launcher_broken), tint = Color.White, modifier = Modifier.size(size * 0.66f))
     }
 }
 
-/** A yellow disc with a warning mark: neither the check nor the X, since this app runs but isn't clean about it. */
-@Composable
-private fun PartialBadge(size: androidx.compose.ui.unit.Dp, modifier: Modifier = Modifier) {
-    Box(
-        modifier.size(size).background(Color(0xFFF9A825), CircleShape),
-        contentAlignment = Alignment.Center,
-    ) {
-        Icon(Icons.Filled.Warning, contentDescription = "Works, but not cleanly, with Gearslip", tint = Color.White, modifier = Modifier.size(size * 0.6f))
-    }
-}
-
-/** Trial: where a tile says whether its app works. See [AppTileBody]. */
-private enum class BadgeStyle { ON_ICON, OUTLINE }
-private val BADGE_STYLE = BadgeStyle.ON_ICON
-
 @OptIn(ExperimentalFoundationApi::class)
 @Composable
-private fun AppTile(tile: Tile) {
-    val status = when {
-        tile.verified -> Color(0xFF43A047)
-        tile.partial -> Color(0xFFF9A825)
-        tile.broken -> Color(0xFFD32F2F)
-        else -> null
-    }
+private fun AppTile(tile: Tile, modifier: Modifier = Modifier) {
     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).then(
-            if (BADGE_STYLE == BadgeStyle.OUTLINE && status != null) Modifier.border(2.5.dp, status, shape) else Modifier,
-        ),
+        modifier = modifier.height(120.dp),
         colors = GsColors(MaterialTheme.colorScheme.surfaceVariant, MaterialTheme.colorScheme.onSurfaceVariant),
         shape = shape,
     ) {
@@ -387,16 +388,14 @@ private fun AppTile(tile: Tile) {
             ) {
                 Box {
                     TileIcon(tile)
-                    if (BADGE_STYLE == BadgeStyle.ON_ICON) {
+                    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.
-                        val ring = Modifier.align(Alignment.BottomEnd).offset(x = 6.dp, y = 4.dp)
-                            .border(2.dp, MaterialTheme.colorScheme.surfaceVariant, CircleShape)
-                        when {
-                            tile.verified -> VerifiedBadge(22.dp, ring)
-                            tile.broken -> BrokenBadge(22.dp, ring)
-                            tile.partial -> PartialBadge(22.dp, ring)
-                        }
+                        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))
@@ -426,3 +425,6 @@ private fun TileLabel(tile: Tile, maxLines: Int = 2, modifier: Modifier = Modifi
         overflow = TextOverflow.Ellipsis,
     )
 }
+
+/** The app opened from the launcher last, where the knob starts on the Apps screen. */
+private const val KEY_LAST_APP = "car_last_app"

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

@@ -0,0 +1,694 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.ui.res.stringResource
+import androidx.compose.material.icons.filled.Call
+import app.seb3thehacker.gearslip.call.CarCalls
+import app.seb3thehacker.gearslip.call.CallUiState
+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
+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.offset
+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.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.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+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.notify.PhoneNavigation
+import app.seb3thehacker.gearslip.car.theme.GsColors
+import app.seb3thehacker.gearslip.car.theme.withTintedSurfaces
+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
+import androidx.compose.ui.platform.LocalDensity
+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
+
+// The nav bar along the bottom of the car screen: home, apps, the assistant, running apps,
+// the next turn or a call, the player, and the clock. Split out of CarUi.kt.
+
+/**
+ * "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, stringResource(R.string.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.shown(),
+                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
+internal 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()
+
+    // A full-width strip along the bottom in the screens' own background, so it reads as part of
+    // the screen above rather than a panel on it. Over the player it's see-through, so the
+    // cover's glow carries on behind it.
+    val overPlayer = navigator.current == CarScreen.Media
+    val navMic by CarSettings.navMic.collectAsState()
+    Surface(color = if (overPlayer) androidx.compose.ui.graphics.Color.Transparent else MaterialTheme.colorScheme.background) {
+        BoxWithConstraints(Modifier.fillMaxWidth().height(NAV_BAR_HEIGHT).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() }
+                if (navMic) {
+                    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.
+                // A call takes the player's place until it ends.
+                // A turn from the phone has no map in the car to show it, so it shows on Home too.
+                val turn = rememberNextTurn()?.takeIf { it.fromPhone || navigator.current != CarScreen.Home }
+                val call = CarCalls.state.collectAsState().value as? CallUiState.Active
+                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)) {
+                        if (call == null || roomForBoth) turn?.let { NavTurnPill(it) { if (!it.fromPhone) navigator.home() } }
+                        if (call != null) {
+                            NavCallPill(call, Modifier.weight(1f, fill = false))
+                        } else 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,
+                                )
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+/**
+ * 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 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 = stringResource(R.string.crumb_home),
+                modifier = Modifier.padding(NAV_ITEM_PADDING).size(28.dp),
+            )
+        }
+    }
+}
+
+/** 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.shownLabel(), 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 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) {
+    GsIconBox(onClick, colors = navColors(selected), latched = selected) {
+        Icon(icon, contentDescription = null, modifier = Modifier.padding(NAV_ITEM_PADDING).size(28.dp))
+    }
+}
+
+/** Wall-clock time, ticking on the minute: no reason to redraw (and re-encode) more often. */
+@Composable
+internal fun rememberNow(): State<Long> = produceState(System.currentTimeMillis()) {
+    while (true) {
+        value = System.currentTimeMillis()
+        delay(60_000 - value % 60_000)
+    }
+}
+
+/** 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, or [fromPhone] a map guiding on the phone. */
+private class NextTurn(val icon: CarIcon?, val distance: String, val road: String, val fromPhone: Boolean = false)
+
+/**
+ * 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
+    val phone by PhoneNavigation.turn.collectAsState()
+    val routing = ((template as? NavigationTemplate)?.navigationInfo as? RoutingInfo)
+        ?.takeIf { status.phase == CarAppConnection.Phase.RUNNING }
+    val step = routing?.takeIf { !it.isLoading }?.currentStep ?: return phone?.let { phoneTurn(it) }
+    return NextTurn(
+        icon = step.maneuver?.icon,
+        distance = routing.currentDistance.display(),
+        road = step.road.text().ifEmpty { step.cue.text() },
+    )
+}
+
+/** Google Maps' or Waze's own arrow, and the distance as the app wrote it. */
+@Composable
+private fun phoneTurn(turn: PhoneNavigation.Turn): NextTurn {
+    val icon = remember(turn.arrow) {
+        turn.arrow?.let { CarIcon.Builder(androidx.core.graphics.drawable.IconCompat.createWithBitmap(it)).build() }
+    }
+    return NextTurn(icon, turn.distance?.display() ?: turn.distanceText, turn.road, fromPhone = true)
+}
+
+/** 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,
+                )
+            }
+        }
+    }
+}
+
+/** The call under way: who, how long, and Mute and End right here. Ringing has its own screen. */
+@Composable
+private fun NavCallPill(call: CallUiState.Active, modifier: Modifier = Modifier) {
+    val context = LocalContext.current.applicationContext
+    val muted by CarCalls.muted.collectAsState()
+    val elapsed by produceState(0L, call.since) {
+        while (true) {
+            value = (android.os.SystemClock.uptimeMillis() - call.since) / 1000
+            delay(1000 - (android.os.SystemClock.uptimeMillis() - call.since) % 1000)
+        }
+    }
+    val scheme = MaterialTheme.colorScheme
+    Surface(
+        modifier = modifier.height(44.dp),
+        shape = RoundedCornerShape(14.dp),
+        color = scheme.secondaryContainer,
+        contentColor = scheme.onSecondaryContainer,
+    ) {
+        Row(
+            Modifier.fillMaxHeight().padding(start = 12.dp, end = 4.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(6.dp),
+        ) {
+            Icon(Icons.Filled.Call, contentDescription = null, modifier = Modifier.size(20.dp))
+            Text(
+                call.caller?.label ?: stringResource(R.string.navbar_on_call),
+                style = MaterialTheme.typography.titleSmall,
+                fontWeight = FontWeight.SemiBold,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = Modifier.weight(1f, fill = false),
+            )
+            Text(
+                "%d:%02d".format(elapsed / 60, elapsed % 60),
+                style = MaterialTheme.typography.titleSmall,
+                maxLines = 1,
+            )
+            Spacer(Modifier.width(2.dp))
+            GsIconButton(
+                if (muted) MediaIcons.MicOff else MediaIcons.Mic,
+                stringResource(if (muted) R.string.navbar_unmute else R.string.navbar_mute),
+                CarCalls::toggleMute,
+                tone = if (muted) GsTone.Primary else GsTone.Neutral, size = 36.dp, iconSize = 22.dp,
+            )
+            GsIconButton(
+                MediaIcons.CallEnd, stringResource(R.string.navbar_end_call), { CarCalls.end(context) },
+                colors = GsColors(scheme.error, scheme.onError), size = 36.dp, iconSize = 22.dp,
+            )
+        }
+    }
+}
+
+/** "Title - Artist" on one line. The text itself cuts it off, and only where the pill runs out of room. */
+@Composable
+private fun nowPlayingLabel(title: String, artist: String): String =
+    listOf(title.trim(), artist.trim()).filter { it.isNotEmpty() }.joinToString(" - ")
+        .ifEmpty { stringResource(R.string.media_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 closes them.
+ */
+@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) }
+    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, stringResource(R.string.player_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,
+                    stringResource(if (now.playing) R.string.player_pause else R.string.media_play),
+                    media::togglePlay,
+                    tone = GsTone.Primary, size = 36.dp, iconSize = 22.dp,
+                )
+                if (!showTitle) {
+                    GsIconButton(
+                        MediaIcons.Next, stringResource(R.string.player_next), media::next,
+                        enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_NEXT), size = 36.dp, iconSize = 22.dp,
+                    )
+                }
+                // Drawn on the side the panel opens on, and filled in while it's open.
+                val playerLeft by CarSettings.playerLeft.collectAsState()
+                val docked = navigator.current == CarScreen.Home && navigator.sidePanel != SidePanel.NONE
+                GsIconButton(
+                    when {
+                        playerLeft && docked -> MediaIcons.DockLeftOpen
+                        playerLeft -> MediaIcons.DockLeft
+                        docked -> MediaIcons.DockRightOpen
+                        else -> MediaIcons.DockRight
+                    },
+                    stringResource(if (docked) R.string.navbar_close_panel else R.string.navbar_dock_player),
+                    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)
+    }
+}

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

@@ -1,5 +1,9 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.runtime.Composable
+import androidx.annotation.StringRes
+import androidx.compose.ui.res.stringResource
+import app.seb3thehacker.gearslip.R
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
@@ -41,7 +45,11 @@ sealed interface 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)
+data class Crumb(val screen: CarScreen, val label: String, @param:StringRes val labelRes: Int = 0) {
+    /** [labelRes] when the step is one of Gearslip's own, translated; [label] for an app's own name. */
+    @Composable
+    fun shown(): String = if (labelRes != 0) stringResource(labelRes) else label
+}
 
 /**
  * Where the car UI is, and how it got there. A car touchscreen has no hardware back button, so
@@ -57,6 +65,7 @@ class CarNavigator(startId: String) {
         Crumb(
             if (CarApps.find(startId) != null) CarScreen.App(startId) else CarScreen.Home,
             "Home",
+            R.string.crumb_home,
         ),
     )
 
@@ -69,15 +78,23 @@ class CarNavigator(startId: String) {
 
     /** 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) {
+    private fun push(screen: CarScreen, label: String, @StringRes labelRes: Int = 0) {
         if (stack.last().screen == screen) return
-        stack.add(Crumb(screen, label))
+        stack.add(Crumb(screen, label, labelRes))
     }
 
+    /**
+     * Whether a back button on this screen leads anywhere the nav bar doesn't: false when the
+     * screen under it is Home or the app grid, which the nav bar's own buttons already reach.
+     * Android Auto shows no back button on an app's first screen for the same reason.
+     */
+    val backLeadsSomewhere: Boolean
+        get() = stack.size >= 2 && stack[stack.size - 2].screen.let { it != CarScreen.Home && it != 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"))
+        stack.add(Crumb(CarScreen.Home, "Home", R.string.crumb_home))
     }
 
     /**
@@ -90,8 +107,9 @@ class CarNavigator(startId: String) {
         private set
 
     /**
-     * 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.
+     * The pill's dock button, an open/close switch for the panel: moves the player beside the map,
+     * going Home first if need be, or closes the panel when something is already there. Switching
+     * between the player and lyrics is done inside the panel itself.
      */
     fun togglePlayerDock() {
         if (current != CarScreen.Home) {
@@ -99,9 +117,11 @@ class CarNavigator(startId: String) {
             home()
             return
         }
-        sidePanel = if (sidePanel == SidePanel.CONTROLS) SidePanel.NONE else SidePanel.CONTROLS
+        sidePanel = if (sidePanel == SidePanel.NONE) SidePanel.CONTROLS else SidePanel.NONE
     }
 
+    fun showSidePlayer() { sidePanel = SidePanel.CONTROLS }
+
     fun showSideLyrics() { sidePanel = SidePanel.LYRICS }
 
     fun closeSidePanel() { sidePanel = SidePanel.NONE }
@@ -114,17 +134,17 @@ class CarNavigator(startId: String) {
 
     fun dismissAppMenu() { appMenu = null }
 
-    fun media() { push(CarScreen.Media, "Media") }
+    fun media() { push(CarScreen.Media, "Media", R.string.crumb_media) }
 
     fun browse(label: String) { push(CarScreen.Browse, label) }
 
-    fun apps() { push(CarScreen.Apps, "Apps") }
+    fun apps() { push(CarScreen.Apps, "Apps", R.string.crumb_apps) }
 
-    fun settings() { push(CarScreen.Settings, "Settings") }
+    fun settings() { push(CarScreen.Settings, "Settings", R.string.settings_title) }
 
-    fun dashboard() { push(CarScreen.Dashboard, "Dashboard") }
+    fun dashboard() { push(CarScreen.Dashboard, "Dashboard", R.string.crumb_dashboard) }
 
-    fun weather() { push(CarScreen.Weather, "Weather") }
+    fun weather() { push(CarScreen.Weather, "Weather", R.string.crumb_weather) }
 
     fun vehicleData() { push(CarScreen.VehicleData, "Vehicle data") }
 
@@ -132,10 +152,10 @@ class CarNavigator(startId: String) {
 
     /** 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")
+        if (replyTo == null) dashboard() else push(CarScreen.Notifications(replyTo), "Reply", R.string.crumb_reply)
     }
 
-    fun open(id: String) { push(CarScreen.App(id), CarApps.find(id)?.label ?: id) }
+    fun open(id: String) { push(CarScreen.App(id), CarApps.find(id)?.label ?: id, CarApps.find(id)?.labelRes ?: 0) }
 
     /** 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. */

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

@@ -5,16 +5,7 @@ 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.
- */
+/** Raw sensor readings, keyed by SensorBatch field number, which matches the sensor type id. */
 object CarSensors {
 
     data class Reading(val typeId: Int, val typeName: String, val raw: String, val updatedAtMs: Long)
@@ -30,16 +21,10 @@ object CarSensors {
         }
     }
 
-    /**
-     * 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.
-     */
+    /** Each SensorBatch field contains repeated readings of one sensor type. */
     fun onEvent(body: ByteArray) {
         val now = System.currentTimeMillis()
-        val fields = Wire.fields(body)
+        val fields = Wire.fields(body).filter { it.wireType == 2 }
         val byType = fields.groupBy { it.number }
         val updated = byType.mapValues { (number, group) ->
             Reading(
@@ -61,10 +46,7 @@ object CarSensors {
     }
 }
 
-/**
- * Sensor type ids as named across public Android Auto reverse-engineering references. Treated as
- * a label, not a fact - see [CarSensors] doc.
- */
+/** Sensor type values shared by the discovery service and SensorBatch. */
 object SensorType {
     private val NAMES = mapOf(
         1 to "Location (GPS)",
@@ -89,6 +71,10 @@ object SensorType {
         20 to "Gyroscope",
         21 to "GPS satellites",
         22 to "Toll card",
+        23 to "Vehicle energy model",
+        24 to "Trailer",
+        25 to "Raw vehicle energy model",
+        26 to "Raw EV trip settings",
     )
 
     fun name(id: Int): String = NAMES[id]?.let { "$it (#$id)" } ?: "Sensor #$id"

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

@@ -2,6 +2,7 @@ package app.seb3thehacker.gearslip.car
 
 import android.content.ComponentName
 import android.content.Context
+import android.media.session.MediaController
 import android.media.session.MediaSessionManager
 import android.media.session.PlaybackState
 import app.seb3thehacker.gearslip.audio.CarAudio
@@ -30,8 +31,25 @@ object CarServices {
 
     private var context: Context? = null
 
+    /** Buffering counts as playing: an app between songs is about to make sound again. */
+    private val PLAYING_STATES = setOf(PlaybackState.STATE_PLAYING, PlaybackState.STATE_BUFFERING)
+    /** How long after pausing for the car leaving to look again for an app that started by itself. */
+    private const val REPAUSE_MS = 2_000L
+
     val nav: CarAppConnection by lazy { CarAppConnection(requireNotNull(context)) }
-    val media: CarMedia by lazy { CarMedia(requireNotNull(context)) }
+    val media: CarMedia by lazy {
+        CarMedia(requireNotNull(context)).also { m ->
+            // Remembered only once it connects: an app that refuses (NewPipe without Notification
+            // access) must not replace the one the driver was listening to on the next drive.
+            m.onReady = { app -> CarSettings.setLastMedia(app.component.flattenToString()) }
+        }
+    }
+
+    /** [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
@@ -54,11 +72,22 @@ object CarServices {
     private var navStopped = false
     private var autoplayPending = false
 
+    /**
+     * The app that was playing, or paused with a track loaded, when the driver opened another one. Opening an app is only a look
+     * at its library: until something plays there, the music carries on in this one, so leaving
+     * the new app's screen goes back to it, as Android Auto does.
+     */
+    private var stillPlaying: MediaApp? = null
+
     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.
@@ -79,15 +108,22 @@ object CarServices {
         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
@@ -108,17 +144,46 @@ object CarServices {
     // --- media ---------------------------------------------------------------------------
 
     fun openMedia(app: MediaApp, autoplay: Boolean = false) {
-        CarSettings.setLastMedia(app.component.flattenToString())
         val phase = media.phase.value
         val live = phase == CarMedia.Phase.READY || phase == CarMedia.Phase.CONNECTING
         if (_mediaApp.value?.component == app.component && live) return
 
+        val previous = _mediaApp.value
+        // Paused counts too: a track loaded there is still the music the driver is listening to.
+        val loaded = media.now.value.let { it.playing || it.title.isNotEmpty() }
+        stillPlaying = previous?.takeIf { it.component != app.component && loaded && !autoplay }
         _mediaApp.value = app
         autoplayPending = autoplay
         media.connect(app)
         // Not torn down and rebuilt per app: the capture covers whatever the phone plays, so
         // switching media apps never costs the driver another consent dialog.
-        if (CarSettings.pipeAudio.value) CarAudio.request()
+        if (CarSettings.pipesNow) 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
+    }
+
+    /**
+     * The media screen closed. If nothing started in the app it showed, go back to the one that
+     * kept playing meanwhile, so the player and its buttons follow the music you can hear.
+     */
+    fun mediaScreenClosed() {
+        val back = stillPlaying ?: return
+        stillPlaying = null
+        // A track loaded here, even one paused since, means the driver used this app.
+        if (media.now.value.playing || media.now.value.title.isNotEmpty()) return
+        app.seb3thehacker.gearslip.GearslipLog.i("media: nothing played in ${_mediaApp.value?.label}, back to ${back.label}")
+        openMedia(back)
     }
 
     /** Closes the media app from the car: stops what it's playing and drops the connection. */
@@ -127,6 +192,7 @@ object CarServices {
         media.disconnect()
         _mediaApp.value = null
         autoplayPending = false
+        stillPlaying = null
     }
 
     /** Called once the media app is connected: starts playback if that was asked for. */
@@ -148,7 +214,7 @@ object CarServices {
             _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 candidates = navApps.filterNot { KnownApps.isBroken(ctx, it.component.packageName) }
             val last = CarSettings.lastNav.value
             // 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
@@ -194,6 +260,83 @@ object CarServices {
         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.
+     * An app can start again on its own once the speaker is given back a moment later, which a
+     * Deezer driver heard after turning the car off (issue #39), so the ones it paused are
+     * looked at once more and paused again if they're playing.
+     */
+    fun pausePhoneMedia(why: String = "the car left") {
+        pausedForNow = null
+        pausedOwnForNow = false
+        val paused = pause(why)
+        if (paused.isEmpty()) return
+        android.os.Handler(android.os.Looper.getMainLooper()).postDelayed({
+            val again = paused.filter { it.playbackState?.state in PLAYING_STATES }
+            again.forEach { runCatching { it.transportControls.pause() } }
+            if (again.isNotEmpty()) {
+                app.seb3thehacker.gearslip.GearslipLog.i("media: paused ${again.joinToString { it.packageName }} again: it started by itself after $why")
+            }
+        }, REPAUSE_MS)
+    }
+
+    /** What [pausePhoneMediaForNow] paused, for [resumePhoneMedia] to play again. */
+    @Volatile private var pausedForNow: List<MediaController>? = null
+    /** Without notification access, whether it paused the app Gearslip drives itself. */
+    @Volatile private var pausedOwnForNow = false
+
+    /** The car wants the speakers for a moment: pause, and remember what to play after. */
+    fun pausePhoneMediaForNow() {
+        pausedOwnForNow = false
+        pausedForNow = pause("the car needs the speakers for a moment")
+    }
+
+    /** The car handed the speakers back: play what it paused, unless the driver has since. */
+    fun resumePhoneMedia() {
+        val paused = pausedForNow ?: return
+        pausedForNow = null
+        if (pausedOwnForNow) {
+            pausedOwnForNow = false
+            mediaOrNull()?.let { if (!it.now.value.playing) it.togglePlay() }
+            return
+        }
+        val waiting = paused.filter { it.playbackState?.state == PlaybackState.STATE_PAUSED }
+        waiting.forEach { runCatching { it.transportControls.play() } }
+        if (waiting.isNotEmpty()) {
+            app.seb3thehacker.gearslip.GearslipLog.i("media: playing ${waiting.joinToString { it.packageName }} again: the car gave the speakers back")
+        }
+    }
+
+    /** What it paused. Without notification access it can only reach the app Gearslip drives itself. */
+    private fun pause(why: String): List<MediaController> {
+        val ctx = context ?: return emptyList()
+        val manager = ctx.getSystemService(MediaSessionManager::class.java)
+        val listener = ComponentName(ctx, GearslipNotificationListener::class.java)
+        val playing = try {
+            manager.getActiveSessions(listener).filter { it.playbackState?.state in PLAYING_STATES }
+        } 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()
+                    pausedOwnForNow = true
+                }
+            }
+            return emptyList()
+        }
+        playing.forEach { runCatching { it.transportControls.pause() } }
+        if (playing.isNotEmpty()) {
+            app.seb3thehacker.gearslip.GearslipLog.i("media: paused ${playing.joinToString { it.packageName }}: $why")
+        }
+        return playing
+    }
+
     /** 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) }
@@ -202,6 +345,8 @@ object CarServices {
         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