Release 0.0.05-alpha: guided setup, downloadable certificate, car phone app, media rework

- First run now asks for permissions one at a time, each on its own screen with an Allow or
  Skip, instead of firing every system dialog at once from a cold start
- The head unit certificate can be downloaded straight from the opencardev/aasdk repository
  with one tap, on top of the existing adb-staged and file-import paths; Settings shows which
  source is active and lets an imported or downloaded certificate be removed
- A phone app on the car screen: a keypad and a searchable contacts list, with a confirmation
  card before every call
- The web browser draws its own on-screen keyboard for a page's text fields, so a search box or
  address bar can be typed into from the car screen
- Media player rework: a dedicated Now Playing tab with a bigger, screen-size-aware layout, an
  Up Next tab showing the app's real queue, and Browse/Lyrics tabs that share the same rail
- Waze and Google Messages are marked broken instead of pretending to work; Google's own dialer,
  Assistant, and Android Auto entries are hidden from the car launcher entirely; Aardvark and
  Vivi Music are marked tested and working
- A help screen replaces the old wall of setup text on the home screen
- The display-calibration screen is gone - it did its job

.github/workflows/release.yml

@@ -0,0 +1,42 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "21"
+
+      - name: Write signing key and properties
+        run: |
+          echo "${{ secrets.KEYSTORE_BASE64 }}" | base64 -d > gearslip-release.jks
+          cat > keystore.properties <<EOF
+          storeFile=gearslip-release.jks
+          storePassword=${{ secrets.KEYSTORE_STORE_PASSWORD }}
+          keyAlias=${{ secrets.KEYSTORE_KEY_ALIAS }}
+          keyPassword=${{ secrets.KEYSTORE_KEY_PASSWORD }}
+          EOF
+
+      - name: Build release APK
+        run: ./gradlew :gearslip:assembleRelease
+
+      - name: Locate APK
+        id: apk
+        run: |
+          apk=$(find gearslip/build/outputs/apk/release -name "*.apk" | head -n1)
+          echo "path=$apk" >> "$GITHUB_OUTPUT"
+
+      - name: Create release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: ${{ steps.apk.outputs.path }}
+          generate_release_notes: true

.gitignore

@@ -22,4 +22,6 @@ keystore.properties
 /docs/cert-sweep.sh
 archive/
 CLAUDE.md
-*.pdf
+*.pdf
+extraction/
+.claude/

README.md

@@ -23,6 +23,11 @@ than Google's own can talk to a car head unit.
   tested against several real navigation and media apps.
 - **Media playback works.** Gearslip lets you browse and control car-enabled media apps
   from the car screen, with lyrics and playback state, over the same host connection.
+- **Audio reaches the car by capturing playback, not by mirroring the screen.** Android
+  requires a screen-share style consent dialog and indicator for this, even though
+  Gearslip never reads the screen; that grant is the only way a non-privileged app can
+  tap another app's audio. The consent normally repeats every drive; the app's own setup
+  steps include two optional adb commands that reduce it to a one-time grant.
 - **A real head unit needs a certificate that Google controls.** A head unit accepts only
   a phone identity that chains to Google's Automotive Link certificate authority, and
   Google alone issues those certificates. Gearslip does not ship one. Without it,
@@ -30,7 +35,9 @@ than Google's own can talk to a car head unit.
   connection. A leaked certificate exists that older head units accept; newer firmware
   and Google's reference tooling reject it.
 - **Gearslip needs no adb, root, or Shizuku.** Every feature relies on an ordinary
-  Android permission or an on-device consent dialog.
+  Android permission or an on-device consent dialog. The two adb commands mentioned
+  above, for audio, are the sole exception: both are optional, and both only remove a
+  dialog that the driver would otherwise see once per drive.
 
 ## Building
 

gearslip/build.gradle.kts

@@ -30,10 +30,10 @@ android {
 
     defaultConfig {
         applicationId = "app.seb3thehacker.gearslip"
-        minSdk = 35
+        minSdk = 31
         targetSdk = 37
-        versionCode = 3
-        versionName = "0.0.03-pre"
+        versionCode = 5
+        versionName = "0.0.05-alpha"
     }
 
     signingConfigs {

gearslip/src/debug/java/app/seb3thehacker/gearslip/BenchAudioSink.kt

@@ -0,0 +1,62 @@
+package app.seb3thehacker.gearslip
+
+import app.seb3thehacker.gearslip.audio.CarAudio
+import kotlin.math.abs
+
+/**
+ * Debug-only stand-in for the head unit's media audio sink.
+ *
+ * The car end of the audio path can only be exercised in a car, but everything before it - the
+ * setting, the consent dialog, the capture service, and whether the media app allows itself to be
+ * heard at all - is phone-side and can be tested at a desk. This sink takes the place of
+ * [AudioLink] so that path runs to completion, and reports what arrived.
+ *
+ *   adb shell am start -n app.seb3thehacker.gearslip/.CarPreviewActivity \
+ *       --ei w 800 --ei h 480 --ez audio true --ei snaps 10
+ *
+ * A healthy run logs a rising byte count and a peak well above zero. A byte count that rises with
+ * a peak of zero means the app refused to be captured.
+ */
+class BenchAudioSink(override val sampleRate: Int = 48_000, override val channels: Int = 2) : CarAudio.Link {
+
+    private var chunks = 0
+    private var bytes = 0L
+    private var peak = 0
+    private var reportedAt = 0L
+
+    override fun start() {
+        chunks = 0
+        bytes = 0
+        peak = 0
+        reportedAt = System.currentTimeMillis()
+        GearslipLog.i("bench sink: started - pretending to be a ${sampleRate}Hz x$channels car sink")
+    }
+
+    override fun stop() {
+        GearslipLog.i("bench sink: stopped after $chunks chunks / $bytes bytes")
+    }
+
+    override fun write(pcm: ByteArray, size: Int) {
+        chunks++
+        bytes += size
+        for (i in 0 until size - 1 step 2) {
+            val sample = (pcm[i].toInt() and 0xFF) or (pcm[i + 1].toInt() shl 8)
+            peak = maxOf(peak, abs(sample.toShort().toInt()))
+        }
+        val now = System.currentTimeMillis()
+        if (now - reportedAt < REPORT_MS) return
+        reportedAt = now
+        val seconds = bytes / (sampleRate.toDouble() * channels * 2)
+        GearslipLog.i(
+            "bench sink: %d chunks / %d bytes (%.1fs of audio), peak %.3f%s".format(
+                chunks, bytes, seconds, peak / 32768f,
+                if (peak == 0) " - SILENT, the app is not letting itself be captured" else "",
+            ),
+        )
+        peak = 0
+    }
+
+    companion object {
+        private const val REPORT_MS = 2_000L
+    }
+}

gearslip/src/debug/java/app/seb3thehacker/gearslip/CarPreviewActivity.kt

@@ -9,6 +9,9 @@ import android.os.Handler
 import android.os.Looper
 import android.view.MotionEvent
 import androidx.activity.ComponentActivity
+import androidx.activity.result.contract.ActivityResultContracts
+import app.seb3thehacker.gearslip.audio.AudioCaptureService
+import app.seb3thehacker.gearslip.audio.CarAudio
 import app.seb3thehacker.gearslip.car.CarEnvironment
 import app.seb3thehacker.gearslip.car.CarSettings
 import app.seb3thehacker.gearslip.car.CarUi
@@ -31,6 +34,28 @@ class CarPreviewActivity : ComponentActivity() {
     private var reader: ImageReader? = null
     @Volatile private var latest: Bitmap? = null
 
+    private val audioPermission = registerForActivityResult(ActivityResultContracts.RequestPermission()) { granted ->
+        if (granted) askAudioCapture() else CarAudio.denied()
+    }
+
+    private val audioConsent = registerForActivityResult(
+        androidx.activity.result.contract.ActivityResultContracts.StartActivityForResult(),
+    ) { result ->
+        val data = result.data
+        if (result.resultCode == RESULT_OK && data != null) {
+            AudioCaptureService.start(this, result.resultCode, data)
+        } else {
+            GearslipLog.w("preview: audio capture consent declined")
+            CarAudio.denied()
+        }
+    }
+
+    private fun askAudioCapture() {
+        val manager = getSystemService(android.media.projection.MediaProjectionManager::class.java)
+        runCatching { audioConsent.launch(manager.createScreenCaptureIntent()) }
+            .onFailure { GearslipLog.e("preview: could not ask for audio capture", it); CarAudio.denied() }
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         GearslipLog.init(this)
@@ -58,6 +83,22 @@ class CarPreviewActivity : ComponentActivity() {
         val p = ScreenProjector(this).also { projector = it }
         p.start(imageReader.surface, w, h, dpi) { CarUi() }
 
+        // Stand in for the car's media sink, so the phone half of the audio path runs for real.
+        if (intent.getBooleanExtra("audio", false)) {
+            CarAudio.onConsentRequested = {
+                runOnUiThread {
+                    if (checkSelfPermission(android.Manifest.permission.RECORD_AUDIO) ==
+                        android.content.pm.PackageManager.PERMISSION_GRANTED
+                    ) {
+                        askAudioCapture()
+                    } else {
+                        audioPermission.launch(android.Manifest.permission.RECORD_AUDIO)
+                    }
+                }
+            }
+            CarAudio.attach(BenchAudioSink())
+        }
+
         GearslipLog.i("preview: displayId=${p.displayId}")
         if (intent.getBooleanExtra("hide", false)) p.setOverlayVisible(false)
 
@@ -123,6 +164,8 @@ class CarPreviewActivity : ComponentActivity() {
         super.onDestroy()
         projector?.stop()
         reader?.close()
+        CarAudio.onConsentRequested = null
+        CarAudio.release()
         CarEnvironment.stop()
     }
 }

gearslip/src/main/AndroidManifest.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
 
     <!-- The projected WebView loads real pages; without this every load fails silently. -->
     <uses-permission android:name="android.permission.INTERNET" />
@@ -23,6 +24,36 @@
     <!-- Capturing a media app's playback (to send to the car) is gated on this by the platform. -->
     <uses-permission android:name="android.permission.RECORD_AUDIO" />
 
+    <!--
+        Playback capture copies a stream rather than moving it, so the phone keeps playing the
+        music it is sending to the car. Silencing the phone's own speaker for the drive needs this.
+    -->
+    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
+
+    <!--
+        Audio capture counts as a screen share, and Android hides notifications during one. The
+        protection can be switched off for the drive, but only with this, granted once over adb
+        (pm grant). Without it Gearslip works the same and notifications stay hidden.
+    -->
+    <uses-permission
+        android:name="android.permission.WRITE_SECURE_SETTINGS"
+        tools:ignore="ProtectedPermissions" />
+
+    <!--
+        Phone calls on the car screen. READ_PHONE_STATE and READ_CALL_LOG together are what a
+        call's own state (ringing, in progress) and the incoming number need; READ_CONTACTS
+        turns that number into a name; ANSWER_PHONE_CALLS lets the driver pick up from here.
+        Declining a call, and the caller ID itself, need Gearslip set as the phone's caller ID
+        and spam app too - an on-device consent, not a permission declared here.
+    -->
+    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
+    <uses-permission android:name="android.permission.READ_CALL_LOG" />
+    <uses-permission android:name="android.permission.READ_CONTACTS" />
+    <uses-permission android:name="android.permission.ANSWER_PHONE_CALLS" />
+
+    <!-- Placing a call from the car screen's dial pad or contacts list needs this. -->
+    <uses-permission android:name="android.permission.CALL_PHONE" />
+
     <!--
       Declared, not just requested. Templated apps decide whether to talk to a host by asking
       whether it holds this permission (HostValidator.isValidHost checks it before falling back
@@ -38,6 +69,10 @@
     <uses-feature android:name="android.hardware.usb.accessory" android:required="true" />
 
     <queries>
+    <!-- Named directly: current builds have no launcher-category entry point for the MAIN/
+         LAUNCHER query below to find, so the setup guide's Android Auto check needs this to see
+         whether the package is installed at all. -->
+    <package android:name="com.google.android.projection.gearhead" />
     <intent>
         <action android:name="android.intent.action.MAIN" />
         <category android:name="android.intent.category.LAUNCHER" />
@@ -142,5 +177,21 @@
                 <action android:name="android.service.notification.NotificationListenerService" />
             </intent-filter>
         </service>
+
+        <!--
+          Sees incoming calls before they ring, so the car screen can show the caller and
+          decline it. Inert until the driver sets Gearslip as the phone's caller ID and spam
+          app, under Settings > Apps > Default apps - the same consent a call-blocking app asks
+          for, not a privileged one.
+        -->
+        <service
+            android:name=".call.GearslipCallScreening"
+            android:exported="true"
+            android:label="Gearslip calls"
+            android:permission="android.permission.BIND_SCREENING_SERVICE">
+            <intent-filter>
+                <action android:name="android.telecom.CallScreeningService" />
+            </intent-filter>
+        </service>
     </application>
 </manifest>

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

@@ -8,7 +8,9 @@ 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_DEBUG_MODE = "debug_mode"
+    private const val KEY_SEEN_PERMISSIONS_SETUP = "seen_permissions_setup"
 
     private fun prefs(context: Context) =
         context.applicationContext.getSharedPreferences(PREFS, Context.MODE_PRIVATE)
@@ -36,6 +38,22 @@ object AppSettings {
         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)
+
+    fun setSkippedCertSetup(context: Context) {
+        prefs(context).edit().putBoolean(KEY_SKIPPED_CERT_SETUP, true).apply()
+    }
+
+    /** Whether the one-by-one permissions wizard has already run once. */
+    fun hasSeenPermissionsSetup(context: Context): Boolean =
+        prefs(context).getBoolean(KEY_SEEN_PERMISSIONS_SETUP, false)
+
+    fun setSeenPermissionsSetup(context: Context) {
+        prefs(context).edit().putBoolean(KEY_SEEN_PERMISSIONS_SETUP, true).apply()
+    }
+
     /**
      * Debug mode: full protocol tracing in the log, and the developer screens (live logs, car
      * preview) on the home screen. On by default while the project is pre-release.

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

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

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

@@ -2,6 +2,7 @@ package app.seb3thehacker.gearslip
 
 import android.content.Context
 import android.net.Uri
+import java.io.ByteArrayOutputStream
 import java.io.File
 import java.security.KeyStore
 import java.security.cert.X509Certificate
@@ -14,7 +15,9 @@ import java.security.cert.X509Certificate
  *
  *  1. **Imported** in the app (Settings > Certificate): a PKCS#12 file plus its password,
  *     copied into the app's private storage.
- *  2. **Staged over adb** into the app's external files directory, the way the spike has
+ *  2. **Downloaded** from the public opencardev/aasdk repository. Fetched only when the
+ *     user asks; the app never ships or hosts the certificate.
+ *  3. **Staged over adb** into the app's external files directory, the way the spike has
  *     always done it. Still honoured, so existing setups keep working untouched:
  *
  *       openssl pkcs12 -export -in headunit.crt -inkey headunit.key \
@@ -23,7 +26,7 @@ import java.security.cert.X509Certificate
  *
  *     Default password is "aaspike" (kept as-is so an already-staged phone.p12 doesn't need
  *     regenerating); a `phone.pass` file next to it overrides it.
- *  3. A freshly generated self-signed cert, which a real head unit rejects (see
+ *  4. A freshly generated self-signed cert, which a real head unit rejects (see
  *     SPIKE_FINDINGS.md).
  */
 object CertProvider {
@@ -34,7 +37,7 @@ object CertProvider {
     private const val DEFAULT_PASSWORD = "aaspike"
     private const val IMPORT_DIR = "identity"
 
-    enum class Kind { IMPORTED, ADB_STAGED, SELF_SIGNED }
+    enum class Kind { IMPORTED, DOWNLOADED, ADB_STAGED, SELF_SIGNED }
 
     class Identity(
         val keyStore: KeyStore,
@@ -70,6 +73,13 @@ object CertProvider {
             }.onFailure { log.e("could not load the imported certificate - trying the next source", it) }
         }
 
+        val downloaded = downloadedFile(context, P12_NAME)
+        if (downloaded.isFile) {
+            runCatching {
+                return loadP12(downloaded, DEFAULT_PASSWORD, "downloaded certificate", Kind.DOWNLOADED)
+            }.onFailure { log.e("could not load the downloaded certificate - trying the next source", it) }
+        }
+
         val dir = context.getExternalFilesDir(null)
         val staged = dir?.let { File(it, P12_NAME) }
         if (dir != null && staged != null && staged.isFile) {
@@ -113,17 +123,84 @@ object CertProvider {
 
     fun hasImported(context: Context): Boolean = importedFile(context, P12_NAME).isFile
 
-    /** Drops the imported identity; the next source in line (adb-staged, then self-signed) takes over. */
+    /** Whether a downloaded certificate is stored (may or may not also be imported). */
+    fun hasDownloaded(context: Context): Boolean = downloadedFile(context, P12_NAME).isFile
+
+    /** Drops the imported identity; the next source in line (downloaded, adb-staged, then self-signed) takes over. */
     fun removeImported(context: Context) {
         importedFile(context, P12_NAME).delete()
         importedFile(context, PASS_NAME).delete()
         log.i("removed the imported certificate")
     }
 
+    /** Drops the downloaded identity. */
+    fun removeDownloaded(context: Context) {
+        downloadedFile(context, P12_NAME).delete()
+        downloadedFile(context, PASS_NAME).delete()
+        log.i("removed the downloaded certificate")
+    }
+
+    /** Whether any certificate is available (imported, downloaded, or adb-staged). */
+    fun hasAnyCert(context: Context): Boolean =
+        hasImported(context) || hasDownloaded(context) || hasAdbStaged(context)
+
+    private fun hasAdbStaged(context: Context): Boolean =
+        context.getExternalFilesDir(null)?.let { File(it, P12_NAME).isFile } == true
+
+    /**
+     * Validates raw PKCS#12 bytes with [password] and, if good, writes them as the imported
+     * identity. Used when the app assembles a certificate in memory (e.g. from a download)
+     * rather than importing from a file picker.
+     */
+    fun importFromBytes(context: Context, p12Bytes: ByteArray, password: String): Identity {
+        val staging = File(context.cacheDir, "import-$P12_NAME")
+        try {
+            staging.writeBytes(p12Bytes)
+            val identity = loadP12(staging, password, "imported certificate", Kind.IMPORTED)
+
+            val target = importedFile(context, P12_NAME)
+            target.parentFile?.mkdirs()
+            staging.copyTo(target, overwrite = true)
+            importedFile(context, PASS_NAME).writeText(password)
+            log.i("imported a certificate from bytes: ${identity.certificate.subjectX500Principal}")
+            return identity
+        } finally {
+            staging.delete()
+        }
+    }
+
+    /**
+     * Downloads the publicly available head unit certificate from the opencardev/aasdk
+     * repository, converts it from PEM to PKCS#12, and stores it ready for use.
+     * Runs synchronously (caller is responsible for threading). Throws on any failure.
+     */
+    fun downloadAndImport(context: Context): Identity {
+        val download = CertDownloader.fetch()
+        val result = PemKeyParser.build(download.certificatePem, download.privateKeyPem)
+
+        val target = downloadedFile(context, P12_NAME)
+        target.parentFile?.mkdirs()
+        val p12Password = DEFAULT_PASSWORD
+        val keyStore = result.keyStore
+        val p12Bytes = ByteArrayOutputStream().use { stream ->
+            keyStore.store(stream, p12Password.toCharArray())
+            stream.toByteArray()
+        }
+        target.writeBytes(p12Bytes)
+        downloadedFile(context, PASS_NAME).writeText(p12Password)
+
+        log.i("downloaded and stored certificate: ${result.certificate.subjectX500Principal}")
+        return Identity(keyStore, result.certificate, p12Password.toCharArray(),
+            "downloaded certificate (opencardev/aasdk)", Kind.DOWNLOADED)
+    }
+
     // The imported files live in the app's private internal storage (not the external files
     // dir), so other apps cannot read the key, and `adb uninstall` clearing it is expected.
     private fun importedFile(context: Context, name: String) = File(File(context.filesDir, IMPORT_DIR), name)
 
+    private fun downloadedFile(context: Context, name: String) =
+        File(File(context.filesDir, "$IMPORT_DIR-downloaded"), name)
+
     private fun importedPassword(context: Context): String =
         importedFile(context, PASS_NAME).takeIf { it.isFile }?.readText().orEmpty()
 

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

@@ -94,24 +94,18 @@ class GearslipActivity : ComponentActivity(), Projection {
         }
     }
 
-    /** Hosted map apps need Gearslip to hold location so they can keep it in the background. */
-    private val locationPermission = registerForActivityResult(
-        androidx.activity.result.contract.ActivityResultContracts.RequestPermission(),
-    ) { granted -> if (granted) Prefetch.warm(this, force = true) }
-
-    /** The car dashboard's agenda card; declined just leaves it empty rather than asking again. */
-    private val calendarPermission = registerForActivityResult(
-        androidx.activity.result.contract.ActivityResultContracts.RequestPermission(),
-    ) { granted -> if (granted) Prefetch.warm(this, force = true) }
+    /** Setting Gearslip as the phone's caller ID and spam app - what lets it decline a ringing call. */
+    private val callScreeningRole = registerForActivityResult(StartActivityForResult()) { result ->
+        if (result.resultCode != RESULT_OK) GearslipLog.w("calls: call screening role declined")
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        if (checkSelfPermission(android.Manifest.permission.ACCESS_FINE_LOCATION) !=
-            android.content.pm.PackageManager.PERMISSION_GRANTED
-        ) locationPermission.launch(android.Manifest.permission.ACCESS_FINE_LOCATION)
-        if (checkSelfPermission(android.Manifest.permission.READ_CALENDAR) !=
-            android.content.pm.PackageManager.PERMISSION_GRANTED
-        ) calendarPermission.launch(android.Manifest.permission.READ_CALENDAR)
+        // Location, calendar, the phone/contacts group, and the microphone are asked for one at
+        // a time by PermissionsSetupScreen instead of here, each only after the driver taps
+        // Allow on a screen explaining what it is for. Firing them all from onCreate, unprompted,
+        // is both a bad first impression and unreliable: Android does not consistently show more
+        // than one system permission dialog fired back-to-back, which was silently dropping some.
         enableEdgeToEdge()
         window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
 
@@ -119,12 +113,17 @@ class GearslipActivity : ComponentActivity(), Projection {
         GearslipLog.installCrashHandler()
         GearslipLog.i("Gearslip ready")
         CarSettings.init(this)
+        // A capture that died without tidying up would leave notifications exposed to every
+        // later screen share. Nothing is capturing if the service is not running, so undo it.
+        if (!app.seb3thehacker.gearslip.audio.AudioCaptureService.running) {
+            app.seb3thehacker.gearslip.audio.ScreenShareGuard.restore(this)
+        }
         Prefetch.warm(this)
         CarEnvironment.setPhoneTheme(resources.configuration)
 
         setContent {
             GearslipTheme {
-                GearslipApp(onDisconnect = ::closeAccessory)
+                GearslipApp(onDisconnect = ::closeAccessory, onRequestCallScreening = ::requestCallScreeningRole)
             }
         }
 
@@ -168,6 +167,19 @@ class GearslipActivity : ComponentActivity(), Projection {
         GearslipLog.flush()
     }
 
+    /** Launches the system dialog that offers Gearslip the call-screening role, if it isn't held already. */
+    private fun requestCallScreeningRole() {
+        val roleManager = getSystemService(android.app.role.RoleManager::class.java)
+        if (roleManager == null || !roleManager.isRoleAvailable(android.app.role.RoleManager.ROLE_CALL_SCREENING)) {
+            GearslipLog.w("calls: call screening role unavailable on this phone")
+            return
+        }
+        if (roleManager.isRoleHeld(android.app.role.RoleManager.ROLE_CALL_SCREENING)) return
+        runCatching {
+            callScreeningRole.launch(roleManager.createRequestRoleIntent(android.app.role.RoleManager.ROLE_CALL_SCREENING))
+        }.onFailure { GearslipLog.e("could not ask for the call screening role", it) }
+    }
+
     // --- Media audio --------------------------------------------------------------------
 
     private fun requestAudioCapture() {

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

@@ -51,6 +51,7 @@ class GearslipRunner(
     @Volatile private var dropped = 0
     @Volatile private var inputChannelId: Int = -1
     @Volatile private var audioLink: AudioLink? = null
+    private var audioMessagesSeen = 0
     private var touchWidth = 0
     private var touchHeight = 0
     private var touchesSeen = 0
@@ -142,6 +143,16 @@ class GearslipRunner(
             } else if (frame.channel == inputChannelId) {
                 onInputMessage(messageId, body)
             } else if (frame.channel == audioLink?.channelId) {
+                // The audio channel is the one still being reverse-engineered, and its first few
+                // replies are what tell us why. Raw bytes for those, then quiet.
+                if (audioMessagesSeen < AUDIO_TRACE_MESSAGES) {
+                    audioMessagesSeen++
+                    log.i(
+                        "audio frame #$audioMessagesSeen: channel=${frame.channel} " +
+                            "encrypted=${frame.encrypted} raw=${frame.payload.size}B decrypted=${message.size}B",
+                    )
+                    log.hex("   audio raw", message, limit = 64)
+                }
                 audioLink?.onMessage(messageId, body)
             } else {
                 log.i("ignoring message id $messageId on channel ${frame.channel}")
@@ -170,16 +181,22 @@ class GearslipRunner(
         log.i("<- VersionRequest: head unit speaks $major.$minor")
         SessionReport.protocolVersion(major, minor)
 
-        // Echo the head unit's own version with STATUS_SUCCESS (0). Echoing rather than
-        // asserting 1.6 is the permissive choice: we only need to reach service discovery,
-        // not to honour whatever that version implies.
+        // PROTOCOL-DOWNGRADE EXPERIMENT. The 2018 Uconnect speaks 1.3 and ACCEPTS the JVC cert;
+        // the 2025 unit speaks 4.3 and rejects it at AuthComplete (-3). If the 4.3 identity check
+        // is tied to the *negotiated* protocol version rather than baked into the firmware,
+        // claiming an older version makes the newer unit skip the check entirely. CLAIM_VERSION
+        // = null restores the previous echo-the-head-unit behaviour.
+        val claim = CLAIM_VERSION ?: (major to minor)
         val response = byteArrayOf(
-            ((major shr 8) and 0xFF).toByte(), (major and 0xFF).toByte(),
-            ((minor shr 8) and 0xFF).toByte(), (minor and 0xFF).toByte(),
+            ((claim.first shr 8) and 0xFF).toByte(), (claim.first and 0xFF).toByte(),
+            ((claim.second shr 8) and 0xFF).toByte(), (claim.second and 0xFF).toByte(),
             0, 0, // STATUS_SUCCESS
         )
         send(MSG_VERSION_RESPONSE, response, encrypted = false)
-        log.i("-> VersionResponse: $major.$minor status=0 (STATUS_SUCCESS)")
+        log.i(
+            "-> VersionResponse: ${claim.first}.${claim.second} status=0 (STATUS_SUCCESS)" +
+                if (CLAIM_VERSION != null) " [FORCED; head unit offered $major.$minor]" else "",
+        )
         state = State.TLS_HANDSHAKE
         SessionStatus.connecting("Securing the link")
         log.i("awaiting ClientHello - the head unit is the TLS client, we are the server")
@@ -360,8 +377,16 @@ class GearslipRunner(
         }
         val media = sinks.firstOrNull { it.streamType == STREAM_MEDIA } ?: run {
             log.w("no media audio sink advertised - media apps will play on the phone only")
+            SessionReport.audio(
+                "no MEDIA sink; head unit offered ${sinks.joinToString { it.streamName }.ifEmpty { "none" }}",
+            )
             return
         }
+        val first = media.configs.firstOrNull()
+        SessionReport.audio(
+            "MEDIA sink on channel ${media.serviceId}, ${media.codecName}, " +
+                "${first?.sampleRate ?: 48_000}Hz/${first?.bits ?: 16}bit/x${first?.channels ?: 2}",
+        )
         audioLink = AudioLink(
             media,
             sendOnChannel = { id, body -> send(id, body, encrypted = true, channel = media.serviceId) },
@@ -768,6 +793,13 @@ class GearslipRunner(
     }
 
     private companion object {
+        /**
+         * Force the protocol version Gearslip claims in VersionResponse, as (major, minor), or
+         * null to echo the head unit. 1.3 is what the 2018 Uconnect (which accepts the JVC cert)
+         * speaks. This is the 2025 identity-check downgrade experiment: see onVersionRequest.
+         */
+        val CLAIM_VERSION: Pair<Int, Int>? = 1 to 3
+
         // protobuf/aap_protobuf/service/control/ControlMessageType.proto:7-17
         const val MSG_VERSION_REQUEST = 1
         const val MSG_VERSION_RESPONSE = 2
@@ -799,6 +831,7 @@ class GearslipRunner(
         const val ACTION_DOWN = 0
         const val ACTION_UP = 1
         const val ACK_STALL_MS = 2_000L
+        const val AUDIO_TRACE_MESSAGES = 6
         const val PERIODIC_KEYFRAME_MS = 5_000L
     }
 }

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

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

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

@@ -42,6 +42,7 @@ object SessionReport {
     @Volatile private var headUnit = ""
     @Volatile private var profile = ""
     @Volatile private var video = ""
+    @Volatile private var audio = ""
     @Volatile private var lastStream = ""
     @Volatile private var lastState = ""
     private var printed = false
@@ -68,6 +69,7 @@ object SessionReport {
     fun headUnit(info: String) { headUnit = info }
     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 }
 
     /** Records the first failure only: later ones are usually fallout from it. */
@@ -107,6 +109,7 @@ object SessionReport {
             append(row("auth status", authStatus?.let { "$it (${authName(it)})" } ?: ""))
             append("\n")
             append(row("video", video))
+            append(row("audio", audio))
             append(row("last stream stat", lastStream))
             append("=".repeat(60))
         }

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

@@ -24,16 +24,51 @@ import kotlin.math.abs
  * Playback capture is the one public route to another app's sound, and it hangs off a
  * MediaProjection - so, as with [app.seb3thehacker.gearslip.mirror.MirrorService], the consent
  * result is carried into a foreground service of type mediaProjection before it can be redeemed.
- * Capture is scoped to the media app's uid: notification pings and other apps stay on the phone.
+ * Capture is scoped to media playback: notification pings, calls and alarms stay on the phone.
+ * The grant lasts as long as this service does, which is as long as the car is connected, so the
+ * driver answers the consent dialog once per drive rather than once per app.
  */
 class AudioCaptureService : Service() {
 
     @Volatile private var reading = false
     private var projection: MediaProjection? = null
     private var thread: Thread? = null
+    private var mutedPhone = false
+
+    /**
+     * Silence the phone's own speaker while the car is being fed.
+     *
+     * Playback capture copies the stream instead of moving it, so without this the music plays in
+     * two places at once. Muting the stream does not affect what is captured - the tap sits before
+     * the volume the speaker gets - so the car still receives full-level audio.
+     */
+    private fun mutePhone() {
+        if (mutedPhone) return
+        runCatching {
+            getSystemService(android.media.AudioManager::class.java)
+                .adjustStreamVolume(android.media.AudioManager.STREAM_MUSIC, android.media.AudioManager.ADJUST_MUTE, 0)
+            mutedPhone = true
+            GearslipLog.i("audio: muted the phone's speaker for the drive")
+        }.onFailure { GearslipLog.w("audio: could not mute the phone: ${it.message}") }
+    }
+
+    private fun unmutePhone() {
+        if (!mutedPhone) return
+        mutedPhone = false
+        runCatching {
+            getSystemService(android.media.AudioManager::class.java)
+                .adjustStreamVolume(android.media.AudioManager.STREAM_MUSIC, android.media.AudioManager.ADJUST_UNMUTE, 0)
+            GearslipLog.i("audio: gave the phone's speaker back")
+        }.onFailure { GearslipLog.w("audio: could not unmute the phone: ${it.message}") }
+    }
 
     override fun onBind(intent: Intent?): IBinder? = null
 
+    override fun onCreate() {
+        super.onCreate()
+        running = true
+    }
+
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
         if (intent?.action == ACTION_STOP) {
             stopSelf()
@@ -49,6 +84,7 @@ class AudioCaptureService : Service() {
         }
 
         startForeground(NOTIFICATION_ID, notification(), ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION)
+        ScreenShareGuard.lift(this)
         projection = try {
             getSystemService(MediaProjectionManager::class.java).getMediaProjection(resultCode, data)
         } catch (t: Throwable) {
@@ -74,13 +110,14 @@ class AudioCaptureService : Service() {
     private fun beginCapture(token: MediaProjection) {
         val rate = CarAudio.sampleRate
         val channels = CarAudio.channels
-        val uid = CarAudio.uid
         val record = try {
+            // Matched by usage, not by app. A uid filter would have to be rebuilt every time the
+            // driver changed media app, and rebuilding means a fresh consent dialog - so the
+            // filter is what the sound is for, and any app playing media reaches the car.
             val config = AudioPlaybackCaptureConfiguration.Builder(token)
                 .addMatchingUsage(AudioAttributes.USAGE_MEDIA)
                 .addMatchingUsage(AudioAttributes.USAGE_GAME)
                 .addMatchingUsage(AudioAttributes.USAGE_UNKNOWN)
-                .apply { if (uid >= 0) addMatchingUid(uid) }
                 .build()
             val mask = if (channels == 1) AudioFormat.CHANNEL_IN_MONO else AudioFormat.CHANNEL_IN_STEREO
             val format = AudioFormat.Builder()
@@ -106,17 +143,25 @@ class AudioCaptureService : Service() {
             val buffer = ByteArray(CHUNK_BYTES)
             var peak = 0
             var heardAt = System.currentTimeMillis()
+            val startedAt = heardAt
+            var everHeard = false
+            var warnedSilent = false
             try {
                 record.startRecording()
-                GearslipLog.i("audio: capturing uid=$uid at ${rate}Hz x$channels")
+                GearslipLog.i("audio: capturing media playback at ${rate}Hz x$channels")
+                mutePhone()
                 CarAudio.captureStarted()
                 while (reading) {
                     val n = record.read(buffer, 0, buffer.size)
-                    if (n <= 0) break
+                    if (n <= 0) {
+                        GearslipLog.e("audio: AudioRecord.read returned $n - capture has stopped")
+                        break
+                    }
                     for (i in 0 until n - 1 step 2) {
                         val sample = (buffer[i].toInt() and 0xFF) or (buffer[i + 1].toInt() shl 8)
                         peak = maxOf(peak, abs(sample.toShort().toInt()))
                     }
+                    if (peak > 0) everHeard = true
                     val now = System.currentTimeMillis()
                     val level = peak / 32768f
                     if (now - heardAt >= LEVEL_LOG_MS) {
@@ -124,6 +169,16 @@ class AudioCaptureService : Service() {
                         heardAt = now
                         peak = 0
                     }
+                    // Capture never fails for an app that opts out; it just hands back digital
+                    // silence. Say so, because the symptom is identical to a broken car link.
+                    if (!everHeard && !warnedSilent && now - startedAt >= SILENCE_MS) {
+                        warnedSilent = true
+                        GearslipLog.w(
+                            "audio: ${SILENCE_MS / 1000}s of capture and every sample is zero. " +
+                                "Either nothing is playing, or the app does not allow its audio " +
+                                "to be captured.",
+                        )
+                    }
                     CarAudio.deliver(buffer, n, level)
                 }
             } catch (t: Throwable) {
@@ -131,6 +186,7 @@ class AudioCaptureService : Service() {
             } finally {
                 runCatching { record.stop() }
                 record.release()
+                unmutePhone()
                 CarAudio.captureStopped()
             }
         }, "gearslip-audio").apply { isDaemon = true; start() }
@@ -140,8 +196,13 @@ class AudioCaptureService : Service() {
         super.onDestroy()
         reading = false
         runCatching { thread?.join(500) }
+        // Belt and braces: a phone left muted after the drive is a bug the driver blames on their
+        // phone, not on Gearslip, so unmute on every way out of here.
+        unmutePhone()
         runCatching { projection?.stop() }
         projection = null
+        ScreenShareGuard.restore(this)
+        running = false
     }
 
     private fun notification(): Notification {
@@ -173,9 +234,14 @@ class AudioCaptureService : Service() {
         /** About 21 ms of 48 kHz stereo: small enough for lip-sync, big enough not to flood the link. */
         private const val CHUNK_BYTES = 4096
         private const val LEVEL_LOG_MS = 3_000L
+        private const val SILENCE_MS = 5_000L
 
         private var appContext: Context? = null
 
+        /** True between onCreate and onDestroy; lets the activity tell a live capture from a crashed one. */
+        @Volatile var running = false
+            private set
+
         fun start(context: Context, resultCode: Int, data: Intent) {
             appContext = context.applicationContext
             context.startForegroundService(

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

@@ -27,10 +27,16 @@ class AudioLink(
     private var configIndex = 0
     @Volatile private var ready = false
     @Volatile private var started = false
+    @Volatile private var focusGranted = false
+    @Volatile private var focusRequested = false
     @Volatile private var inFlight = 0
-    @Volatile private var maxUnacked = 8
+    // The Uconnect asks for 4 on its video channel; assume the same until its Config says otherwise.
+    @Volatile private var maxUnacked = 4
     @Volatile private var lastAckAt = 0L
     private var chunks = 0
+    private var bytes = 0L
+    private var dropped = 0
+    @Volatile private var configTimer: Thread? = null
 
     private val config get() = service.configs.getOrNull(configIndex) ?: service.configs.firstOrNull()
     override val sampleRate get() = config?.sampleRate ?: 48_000
@@ -39,12 +45,47 @@ class AudioLink(
     val channelId get() = service.serviceId
 
     fun opened(status: Int) {
+        GearslipLog.i("audio: <- ChannelOpenResponse (media audio): status=$status")
         if (status != 0) {
             GearslipLog.w("audio: the head unit refused the media audio channel (status $status)")
             return
         }
-        sendOnChannel(MSG_SETUP, Protobuf.varintField(1, service.codecType.toLong()))
-        GearslipLog.i("audio: -> Setup(codec=${service.codecName})")
+        // 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}")
+        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.
+     *
+     * 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.
+     */
+    private fun armConfigFallback() {
+        val timer = Thread({
+            try {
+                Thread.sleep(CONFIG_WAIT_MS)
+            } 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)
+        }, "gearslip-audio-config").apply { isDaemon = true }
+        configTimer = timer
+        timer.start()
     }
 
     fun onMessage(messageId: Int, body: ByteArray) {
@@ -60,9 +101,15 @@ class AudioLink(
                 if (window != null) maxUnacked = maxOf(1, window)
                 configIndex = indices.firstOrNull() ?: 0
                 if (status == STATUS_READY) {
+                    configTimer?.interrupt()
                     ready = true
-                    GearslipLog.i("audio: ready - ${sampleRate}Hz x$channels ${config?.bits}bit")
+                    GearslipLog.i("audio: sink ready - ${sampleRate}Hz x$channels ${config?.bits}bit")
                     CarAudio.attach(this)
+                } else {
+                    GearslipLog.w(
+                        "audio: the sink is not ready (status=$status, 1=WAIT 2=READY) - " +
+                            "nothing will be sent until it is",
+                    )
                 }
             }
 
@@ -72,17 +119,40 @@ class AudioLink(
                 lastAckAt = System.currentTimeMillis()
             }
 
-            else -> GearslipLog.i("audio: <- unhandled message id=$messageId (${body.size} bytes)")
+            // 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)")
+                GearslipLog.hex("   audio msg", body, limit = 64)
+            }
         }
     }
 
+    /**
+     * The head unit's answer to our AudioFocusRequest. Until it grants focus the sink is wired to
+     * whatever else the car is playing - the radio, usually - and anything we send is discarded,
+     * so [start] waits here rather than streaming into nothing.
+     */
     fun onFocus(state: Int) {
-        GearslipLog.i("audio: <- AudioFocus state=$state (1=GAIN, 2=GAIN_TRANSIENT, 3=LOSS, 4=LOSS_TRANSIENT)")
+        val name = FOCUS_STATES[state] ?: "unknown($state)"
+        GearslipLog.i("audio: <- AudioFocusResponse state=$name")
+        focusGranted = state == FOCUS_STATE_GAIN || state == FOCUS_STATE_GAIN_TRANSIENT
+        if (focusGranted) startStream() else stop()
     }
 
     override fun start() {
         if (!ready || started) return
-        sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_GAIN.toLong()))
+        if (!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")
+        }
+        // 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()
+    }
+
+    private fun startStream() {
+        if (!ready || started) return
         sendOnChannel(
             MSG_START,
             Protobuf.varintField(1, SESSION_ID.toLong()) + Protobuf.varintField(2, configIndex.toLong()),
@@ -90,7 +160,7 @@ class AudioLink(
         inFlight = 0
         lastAckAt = System.currentTimeMillis()
         started = true
-        GearslipLog.i("audio: -> AudioFocusRequest(GAIN), Start(config=$configIndex)")
+        GearslipLog.i("audio: -> Start(session=$SESSION_ID, config=$configIndex) - streaming ${sampleRate}Hz x$channels")
     }
 
     override fun stop() {
@@ -98,17 +168,26 @@ class AudioLink(
         started = false
         runCatching {
             sendOnChannel(MSG_STOP, Protobuf.varintField(1, SESSION_ID.toLong()))
-            sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_RELEASE.toLong()))
+            if (focusRequested) sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_RELEASE.toLong()))
         }
-        GearslipLog.i("audio: -> Stop, AudioFocusRequest(RELEASE) after $chunks chunks")
+        focusRequested = false
+        focusGranted = false
+        GearslipLog.i("audio: -> Stop, AudioFocusRequest(RELEASE) after $chunks chunks / $bytes bytes")
         chunks = 0
+        bytes = 0
     }
 
     override fun write(pcm: ByteArray, size: Int) {
         if (!started) return
         if (inFlight >= maxUnacked) {
             // A lost ack must not silence the stream for good; after a stall assume the window cleared.
-            if (System.currentTimeMillis() - lastAckAt > STALL_MS) inFlight = 0 else return
+            if (System.currentTimeMillis() - lastAckAt > STALL_MS) {
+                GearslipLog.w("audio: no ack for ${STALL_MS}ms with $inFlight in flight - reopening the window")
+                inFlight = 0
+            } else {
+                dropped++
+                return
+            }
         }
         val timestamp = ByteArray(8)
         val micros = System.nanoTime() / 1_000
@@ -116,14 +195,26 @@ class AudioLink(
         try {
             sendOnChannel(MSG_DATA, timestamp + pcm.copyOf(size))
         } catch (e: java.io.IOException) {
+            GearslipLog.e("audio: the link died mid-stream", e)
             started = false
             return
         }
         inFlight++
         chunks++
+        bytes += 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/$maxUnacked, " +
+                    "dropped=$dropped, focus=${if (focusGranted) "granted" else "not granted"}",
+            )
+        }
     }
 
     fun close() {
+        configTimer?.interrupt()
+        configTimer = null
         stop()
         ready = false
         CarAudio.detach(this)
@@ -142,7 +233,15 @@ class AudioLink(
         private const val STATUS_READY = 2
         private const val FOCUS_GAIN = 1
         private const val FOCUS_RELEASE = 4
+        private const val FOCUS_STATE_GAIN = 1
+        private const val FOCUS_STATE_GAIN_TRANSIENT = 2
         private const val SESSION_ID = 2
         private const val STALL_MS = 2_000L
+        private const val CHUNK_LOG_EVERY = 200 // about every four seconds
+        private const val CONFIG_WAIT_MS = 2_500L
+
+        private val FOCUS_STATES = mapOf(
+            1 to "GAIN", 2 to "GAIN_TRANSIENT", 3 to "LOSS", 4 to "LOSS_TRANSIENT",
+        )
     }
 }

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

@@ -6,12 +6,15 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 
 /**
- * Joins the two ends of the audio path: [AudioCaptureService] on the phone, which hears what a
- * media app plays, and the car's audio channel, which is where it has to end up.
+ * Joins the two ends of the audio path: [AudioCaptureService] on the phone, which hears what the
+ * phone is playing, and the car's audio channel, which is where it has to end up.
  *
- * They come and go independently. The phone side needs on-device consent and can be running on
- * the bench with no car attached; the car side exists only while a head unit is connected and
- * offers a media audio sink. Whichever pair is present, samples flow.
+ * Capture belongs to the car session, not to any one app. Android grants it through a consent
+ * dialog that cannot be answered in advance or remembered, so Gearslip asks once, when a head unit
+ * first offers a sink to play through, and then holds that grant for as long as the car is
+ * connected. Switching between media apps, or starting playback from the phone, costs nothing
+ * further: the capture is by audio usage rather than by app, so whatever the phone plays as media
+ * goes to the car.
  */
 object CarAudio {
 
@@ -36,9 +39,8 @@ object CarAudio {
     /** Set by the activity: shows the permission and consent dialogs, which only it can. */
     var onConsentRequested: (() -> Unit)? = null
 
-    /** The uid being captured (or waited on). */
-    @Volatile var uid: Int = -1
-        private set
+    /** Whether the driver has asked for the car to be fed at all; see CarSettings.pipeAudio. */
+    @Volatile private var wanted = false
 
     @Volatile private var link: Link? = null
 
@@ -48,30 +50,48 @@ object CarAudio {
 
     fun attach(link: Link) {
         this.link = link
-        if (_capture.value == Capture.ON) link.start()
+        GearslipLog.i("audio: the car offered a sink at ${link.sampleRate}Hz x${link.channels}")
+        when {
+            _capture.value == Capture.ON -> link.start()
+            wanted -> ask()
+        }
     }
 
     fun detach(link: Link) {
         if (this.link === link) this.link = null
     }
 
-    /** A media app was opened: start hearing it. */
-    fun request(uid: Int) {
-        if (this.uid == uid && _capture.value != Capture.OFF && _capture.value != Capture.DENIED) return
-        if (this.uid != uid) AudioCaptureService.stop()
-        this.uid = uid
-        _capture.value = Capture.ASKING
-        val ask = onConsentRequested
-        if (ask == null) {
-            GearslipLog.w("audio: nothing on the phone can ask for capture consent")
-            _capture.value = Capture.DENIED
-        } else {
-            ask()
+    /**
+     * 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
+     * sound has nowhere to go, would put a system dialog in front of the driver for nothing.
+     */
+    fun request() {
+        wanted = true
+        when (_capture.value) {
+            Capture.ON, Capture.ASKING, Capture.DENIED -> return
+            Capture.OFF -> if (link == null) {
+                GearslipLog.i("audio: waiting for the car to offer an audio sink")
+            } else {
+                ask()
+            }
         }
     }
 
+    private fun ask() {
+        _capture.value = Capture.ASKING
+        val request = onConsentRequested
+        if (request == null) {
+            GearslipLog.w("audio: nothing on the phone can ask for capture consent")
+            _capture.value = Capture.DENIED
+        } else {
+            request()
+        }
+    }
+
+    /** The car went away. Everything is torn down; the next connection asks again. */
     fun release() {
-        uid = -1
+        wanted = false
         AudioCaptureService.stop()
         _capture.value = Capture.OFF
     }

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

@@ -0,0 +1,64 @@
+package app.seb3thehacker.gearslip.audio
+
+import android.Manifest
+import android.content.Context
+import android.content.pm.PackageManager
+import android.provider.Settings
+import app.seb3thehacker.gearslip.GearslipLog
+
+/**
+ * Keeps the phone's notifications readable while audio is being sent to the car.
+ *
+ * Playback capture hangs off a MediaProjection, and since Android 15 any full-screen projection
+ * makes SystemUI hide notification contents, on the assumption that someone is watching the
+ * screen. Nobody is: the audio projection never makes a display. The one exemption an ordinary app
+ * can reach is the developer setting that switches the protection off, so Gearslip turns it off for
+ * the length of the capture and back on afterwards.
+ *
+ * Writing it needs WRITE_SECURE_SETTINGS, granted once over adb. Without the grant this does
+ * nothing and notifications stay hidden while music plays, which is the platform's default.
+ *
+ * Phone mirroring deliberately does not use this: there the screen really is being shown.
+ */
+internal object ScreenShareGuard {
+
+    /** Settings.Global.DISABLE_SCREEN_SHARE_PROTECTIONS_FOR_APPS_AND_NOTIFICATIONS, hidden API. */
+    private const val SETTING = "disable_screen_share_protections_for_apps_and_notifications"
+    private const val PREFS = "gearslip_screen_share_guard"
+
+    /** Set while Gearslip has the protection switched off, so a crash can be undone at next launch. */
+    private const val KEY_LIFTED = "lifted"
+
+    fun canLift(context: Context): Boolean =
+        context.checkSelfPermission(Manifest.permission.WRITE_SECURE_SETTINGS) ==
+            PackageManager.PERMISSION_GRANTED
+
+    /** Call before the projection starts: the system decides what to hide at that moment. */
+    fun lift(context: Context) {
+        if (!canLift(context)) {
+            GearslipLog.i("audio: notifications will be hidden while capturing (no WRITE_SECURE_SETTINGS)")
+            return
+        }
+        val resolver = context.contentResolver
+        // Already off, whether by the driver in Developer options or by us: leave it as found.
+        if (Settings.Global.getInt(resolver, SETTING, 0) != 0) return
+        runCatching {
+            prefs(context).edit().putBoolean(KEY_LIFTED, true).commit()
+            Settings.Global.putInt(resolver, SETTING, 1)
+            GearslipLog.i("audio: screen share protection off for the drive, notifications stay visible")
+        }.onFailure { GearslipLog.w("audio: could not lift screen share protection: ${it.message}") }
+    }
+
+    /** Put the protection back, if Gearslip is the one that took it away. */
+    fun restore(context: Context) {
+        if (!prefs(context).getBoolean(KEY_LIFTED, false)) return
+        runCatching {
+            Settings.Global.putInt(context.contentResolver, SETTING, 0)
+            prefs(context).edit().remove(KEY_LIFTED).commit()
+            GearslipLog.i("audio: screen share protection back on")
+        }.onFailure { GearslipLog.w("audio: could not restore screen share protection: ${it.message}") }
+    }
+
+    private fun prefs(context: Context) =
+        context.applicationContext.getSharedPreferences(PREFS, Context.MODE_PRIVATE)
+}

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

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

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

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

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

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

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

@@ -0,0 +1,132 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Call
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.FilledIconButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButtonDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.call.CallUiState
+import app.seb3thehacker.gearslip.call.CarCalls
+
+/**
+ * Sits above whatever the car is showing while a call is ringing or under way. Ringing takes the
+ * whole screen, because nothing else matters more right now; an active call is a thin band along
+ * the top, since from here the driver can only see who it is, not end it - see [CarCalls].
+ */
+@Composable
+fun CallOverlay(modifier: Modifier = Modifier) {
+    val state by CarCalls.state.collectAsState()
+    val context = LocalContext.current.applicationContext
+
+    when (val s = state) {
+        // Covers the box regardless of where the caller aligned it, so the alignment below is
+        // only ever felt by the active-call banner, which is the one that isn't full-screen.
+        is CallUiState.Ringing -> IncomingCall(s, onAnswer = { CarCalls.answer(context) }, onDecline = CarCalls::decline)
+        is CallUiState.Active -> ActiveCallBanner(s, modifier)
+        CallUiState.None -> {}
+    }
+}
+
+@Composable
+private fun IncomingCall(s: CallUiState.Ringing, onAnswer: () -> Unit, onDecline: () -> Unit) {
+    Surface(Modifier.fillMaxSize(), color = MaterialTheme.colorScheme.surfaceContainerLowest) {
+        Column(
+            Modifier.fillMaxSize().padding(32.dp),
+            horizontalAlignment = Alignment.CenterHorizontally,
+            verticalArrangement = Arrangement.Center,
+        ) {
+            Icon(
+                Icons.Filled.Call,
+                contentDescription = null,
+                modifier = Modifier.size(64.dp),
+                tint = MaterialTheme.colorScheme.primary,
+            )
+            Spacer(Modifier.height(16.dp))
+            Text(
+                "Incoming call",
+                style = MaterialTheme.typography.titleMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+            Spacer(Modifier.height(8.dp))
+            Text(
+                s.caller.label,
+                style = MaterialTheme.typography.displaySmall,
+                fontWeight = FontWeight.Bold,
+                textAlign = TextAlign.Center,
+            )
+            Spacer(Modifier.height(56.dp))
+            Row(horizontalArrangement = Arrangement.spacedBy(48.dp)) {
+                CallButton(Icons.Filled.Close, "Decline", MaterialTheme.colorScheme.error, enabled = s.canDecline, onClick = onDecline)
+                CallButton(Icons.Filled.Call, "Answer", MaterialTheme.colorScheme.primary, enabled = true, onClick = onAnswer)
+            }
+            if (!s.canDecline) {
+                Spacer(Modifier.height(20.dp))
+                Text(
+                    "Already ringing out loud - answer here, or let it ring.",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun CallButton(icon: ImageVector, label: String, color: Color, enabled: Boolean, onClick: () -> Unit) {
+    Column(horizontalAlignment = Alignment.CenterHorizontally) {
+        FilledIconButton(
+            onClick = onClick,
+            enabled = enabled,
+            modifier = Modifier.size(72.dp),
+            colors = IconButtonDefaults.filledIconButtonColors(containerColor = color, contentColor = Color.White),
+        ) { Icon(icon, contentDescription = label, modifier = Modifier.size(30.dp)) }
+        Spacer(Modifier.height(8.dp))
+        Text(label, style = MaterialTheme.typography.labelLarge)
+    }
+}
+
+@Composable
+private fun ActiveCallBanner(s: CallUiState.Active, modifier: Modifier = Modifier) {
+    Surface(
+        color = MaterialTheme.colorScheme.primaryContainer,
+        contentColor = MaterialTheme.colorScheme.onPrimaryContainer,
+        modifier = modifier.fillMaxWidth(),
+    ) {
+        Row(
+            Modifier.padding(horizontal = 20.dp, vertical = 10.dp),
+            horizontalArrangement = Arrangement.Center,
+        ) {
+            Icon(Icons.Filled.Call, contentDescription = null, modifier = Modifier.size(20.dp))
+            Spacer(Modifier.height(0.dp))
+            Text(
+                "  On a call" + (s.caller?.let { " with ${it.label}" } ?: ""),
+                style = MaterialTheme.typography.labelLarge,
+                fontWeight = FontWeight.SemiBold,
+            )
+        }
+    }
+}

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

@@ -1,7 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.Info
+import androidx.compose.material.icons.filled.Call
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material.icons.filled.Share
 import androidx.compose.material.icons.filled.Settings
@@ -28,8 +28,8 @@ object CarApps {
         CarApp("phone", "Screen sharing", Icons.Filled.Share) {
             PhoneAppsScreen()
         },
-        CarApp("calibrate", "Display test", Icons.Filled.Info) {
-            CalibrationApp()
+        CarApp("dialer", "Phone", Icons.Filled.Call) {
+            PhoneDialerScreen()
         },
         CarApp("settings", "Settings", Icons.Filled.Settings) {
             CarSettingsScreen()

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

@@ -1,10 +1,8 @@
 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.Spacer
 import androidx.compose.foundation.layout.fillMaxHeight
@@ -13,11 +11,8 @@ 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 androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.PlayArrow
-import androidx.compose.material3.FilledIconButton
-import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -27,32 +22,26 @@ import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.produceState
-import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.ui.draw.clip
-import android.media.session.PlaybackState
-import androidx.compose.ui.graphics.asImageBitmap
-import androidx.compose.ui.layout.ContentScale
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import app.seb3thehacker.gearslip.host.CarAppConnection
 import app.seb3thehacker.gearslip.media.CarMedia
-import app.seb3thehacker.gearslip.media.MediaArt
-import kotlinx.coroutines.delay
+import app.seb3thehacker.gearslip.media.NowPlaying
+import kotlinx.coroutines.launch
 
 /**
- * The home screen: the map on the left, what is playing on the right.
+ * The home screen: the map on the left, lyrics on the right when asked for.
  *
- * The map is whatever navigation app was used last, brought back on its own. The player only
- * takes its share of the screen only while something is playing or paused; otherwise the map has all of it.
+ * The map is whatever navigation app was used last, brought back on its own. Playback itself is
+ * controlled from the nav bar's pill everywhere, including here - this column only opens when the
+ * pill's lyrics button is on, and closes itself back to a full-width map once nothing is playing.
  */
 @Composable
 fun CarHome() {
@@ -65,21 +54,19 @@ fun CarHome() {
     LaunchedEffect(phase) { if (phase == CarMedia.Phase.READY) CarServices.autoplayIfDue() }
 
     val navigator = LocalCarNavigator.current
-    val showPlayer = phase == CarMedia.Phase.READY && now.isActive && !navigator.playerMinimised
-    // Once playback ends there is nothing left to minimise; the next song starts in place.
-    LaunchedEffect(now.isActive) { if (!now.isActive) navigator.restorePlayer() }
+    val showLyrics = phase == CarMedia.Phase.READY && now.isActive && navigator.lyricsOpen
 
     Row(Modifier.fillMaxSize().padding(8.dp), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
         Box(
             Modifier
-                .weight(if (showPlayer) 2.1f else 1f)
+                .weight(if (showLyrics) 2.1f else 1f)
                 .fillMaxHeight()
                 .clip(RoundedCornerShape(EMBEDDED_RADIUS)),
         ) {
             MapPane(navStatus, frame)
         }
-        if (showPlayer) {
-            MiniPlayer(Modifier.weight(1f).fillMaxHeight())
+        if (showLyrics) {
+            LyricsColumn(now, Modifier.weight(1f).fillMaxHeight())
         }
     }
 }
@@ -98,6 +85,7 @@ private fun MapPane(status: CarAppConnection.Status, frame: CarEnvironment.Frame
         horizontalAlignment = Alignment.CenterHorizontally,
     ) {
         val hasLast = CarSettings.lastNav.value != null
+        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)
@@ -107,110 +95,56 @@ private fun MapPane(status: CarAppConnection.Status, frame: CarEnvironment.Frame
                 TextButton(onClick = navigator::apps) { Text("Choose another app") }
             }
             else -> {
+                // 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(
-                    if (hasLast) "Starting the map…" else "No map app chosen yet.",
+                    if (hasLast) "Map stopped." else "No map app chosen yet.",
                     style = MaterialTheme.typography.titleMedium,
                 )
-                if (!hasLast) {
+                if (hasLast) {
+                    TextButton(onClick = { scope.launch { CarServices.reconnectNav(frame) } }) { Text("Reopen") }
+                } else {
                     Text(
                         "Open Car apps and connect a navigation app; it will start here next time.",
                         style = MaterialTheme.typography.bodyMedium,
                         color = MaterialTheme.colorScheme.onSurfaceVariant,
                     )
-                    TextButton(onClick = { navigator.apps() }) { Text("Car apps") }
                 }
+                TextButton(onClick = { navigator.apps() }) { Text("Car apps") }
             }
         }
     }
 }
 
-/** Previous, play/pause, next and a seek bar, and nothing else: the full controls are in the media screen. */
+/**
+ * Lyrics for whatever the nav bar's pill is playing, beside the map. Transport controls live in
+ * the pill itself now, not here - this column has exactly one job.
+ */
 @Composable
-private fun MiniPlayer(modifier: Modifier) {
-    val media = CarServices.media
-    val now by media.now.collectAsStateWithLifecycle()
-    val context = LocalContext.current
-    val art by produceState(now.art, now.art, now.artUri) { value = now.art ?: MediaArt.load(context, now.artUri) }
-
-    var position by remember { mutableStateOf(0L) }
-    LaunchedEffect(now) {
-        while (true) {
-            position = now.currentPosition()
-            delay(500)
-        }
-    }
-
+private fun LyricsColumn(now: NowPlaying, modifier: Modifier) {
     val navigator = LocalCarNavigator.current
     Surface(
-        onClick = { navigator.media() },
         modifier = modifier,
         shape = RoundedCornerShape(EMBEDDED_RADIUS),
         color = MaterialTheme.colorScheme.surfaceVariant,
     ) {
-        Column(
-            Modifier.fillMaxSize().padding(18.dp),
-            horizontalAlignment = Alignment.CenterHorizontally,
-            verticalArrangement = Arrangement.Center,
-        ) {
-            Box(Modifier.size(128.dp).clip(RoundedCornerShape(EMBEDDED_RADIUS))) {
-                art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
-            }
-            Spacer(Modifier.height(10.dp))
-            Text(
-                now.title.ifEmpty { "Nothing playing" },
-                style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
-                maxLines = 1, overflow = TextOverflow.Ellipsis,
-            )
-            Text(
-                now.artist,
-                style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant,
-                maxLines = 1, overflow = TextOverflow.Ellipsis,
-            )
-
-            if (now.durationMs > 0) {
-                WavyProgress(
-                    fraction = position.toFloat() / now.durationMs,
-                    playing = now.state == PlaybackState.STATE_PLAYING,
-                    onSeek = { media.seek((it * now.durationMs).toLong()) },
-                    modifier = Modifier.padding(vertical = 4.dp),
+        Column(Modifier.fillMaxSize().padding(16.dp)) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Text(
+                    now.title.ifEmpty { "Lyrics" },
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.SemiBold,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                    modifier = Modifier.weight(1f),
                 )
-            } else {
-                Spacer(Modifier.height(16.dp))
-            }
-
-            Row(
-                horizontalArrangement = Arrangement.spacedBy(6.dp),
-                verticalAlignment = Alignment.CenterVertically,
-            ) {
-                IconButton(onClick = { media.previous() }, modifier = Modifier.size(48.dp)) {
-                    Icon(MediaIcons.Previous, "Previous", Modifier.size(30.dp))
-                }
-                FilledIconButton(onClick = media::togglePlay, modifier = Modifier.size(60.dp)) {
-                    Icon(
-                        if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow,
-                        if (now.playing) "Pause" else "Play",
-                        Modifier.size(36.dp),
-                    )
-                }
-                IconButton(onClick = { media.next() }, modifier = Modifier.size(48.dp)) {
-                    Icon(MediaIcons.Next, "Next", Modifier.size(30.dp))
+                IconButton(onClick = navigator::toggleLyrics, modifier = Modifier.size(36.dp)) {
+                    Icon(Icons.Filled.Close, "Hide lyrics", Modifier.size(20.dp))
                 }
             }
-
-            Spacer(Modifier.height(8.dp))
-            Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
-                val compact = PaddingValues(horizontal = 8.dp)
-                FilledTonalButton(
-                    onClick = { navigator.media(lyrics = true) },
-                    modifier = Modifier.weight(1f),
-                    contentPadding = compact,
-                ) { Text("Lyrics", maxLines = 1, softWrap = false) }
-                FilledTonalButton(
-                    onClick = navigator::minimisePlayer,
-                    modifier = Modifier.weight(1f),
-                    contentPadding = compact,
-                ) { Text("Minimise", maxLines = 1, softWrap = false) }
-            }
+            Spacer(Modifier.height(4.dp))
+            LyricsPanel(now, Modifier.weight(1f).fillMaxWidth())
         }
     }
 }

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

@@ -1,6 +1,9 @@
 package app.seb3thehacker.gearslip.car
 
 import androidx.compose.foundation.Image
+import androidx.compose.foundation.ExperimentalFoundationApi
+import androidx.compose.foundation.border
+import androidx.compose.foundation.combinedClickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
@@ -13,6 +16,7 @@ import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Call
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material.icons.filled.Settings
 import androidx.compose.material.icons.filled.Share
@@ -45,6 +49,7 @@ import androidx.compose.foundation.background
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.lazy.grid.GridItemSpan
 import androidx.compose.material.icons.filled.Check
+import androidx.compose.material.icons.filled.Close
 import app.seb3thehacker.gearslip.host.KnownApps
 import app.seb3thehacker.gearslip.host.CarAppCatalog
 import app.seb3thehacker.gearslip.host.TemplateApp
@@ -60,23 +65,31 @@ private class Tile(
     val glyph: ImageVector? = null,
     /** Tested from start to finish with Gearslip; drawn with a check mark. */
     val verified: Boolean = false,
+    /** Known not to work; drawn with a red X instead of being left off the launcher. */
+    val broken: Boolean = false,
+    val pinned: Boolean = false,
+    /** Null for the built-in tiles (Web, Screen sharing, Settings) - nothing to pin them as. */
+    val onLongClick: (() -> Unit)? = null,
     val onClick: () -> Unit,
 )
 
 /** A launcher app's data, kept apart from [Tile] so it can be cached without capturing click state. */
-private class Entry(
+internal class Entry(
     val label: String,
     val icon: ImageBitmap?,
     val template: TemplateApp? = null,
     val media: MediaApp? = null,
-)
+) {
+    /** What a pin or a nav-bar shortcut remembers this entry as; null for nothing pinnable. */
+    val componentId: String? get() = (template?.component ?: media?.component)?.flattenToString()
+}
 
 /**
  * The installed car and media apps with their icons. Scanning the package manager and decoding
  * icons is slow, so [Prefetch] does it ahead of time and again at the start of each car session,
  * which is when new installs are picked up.
  */
-private object LauncherCache {
+internal object LauncherCache {
     @Volatile var entries: List<Entry>? = null
 
     /** Returns the scan if there is one; [force] rescans. Synchronized so two callers share one scan. */
@@ -96,6 +109,16 @@ private object LauncherCache {
 /** 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) }
 
+/**
+ * Connects or opens [entry] - what tapping its tile does, shared with the nav bar's pinned
+ * shortcuts and its open-app icon so there is exactly one place that knows how to launch either
+ * kind of app.
+ */
+internal fun launchEntry(entry: Entry, navigator: CarNavigator, frame: CarEnvironment.Frame) {
+    entry.template?.let { CarServices.connectNav(it, frame); navigator.home() }
+    entry.media?.let { CarServices.openMedia(it); navigator.media() }
+}
+
 /** The app launcher: Web and Screen sharing, every car app the phone has, then Settings, as an icon grid. */
 @Composable
 fun CarLauncher() {
@@ -108,15 +131,22 @@ fun CarLauncher() {
         value = LauncherCache.entries ?: withContext(Dispatchers.IO) { LauncherCache.load(context) }
     }
 
+    val pinned by CarSettings.pinnedApps.collectAsState()
+
     val tiles = listOf(
         Tile("Web", glyph = Icons.Filled.Search) { navigator.open("web") },
         Tile("Screen sharing", glyph = Icons.Filled.Share) { navigator.open("phone") },
+        Tile("Phone", glyph = Icons.Filled.Call) { navigator.open("dialer") },
     ) + installed.map { entry ->
         val pkg = entry.template?.component?.packageName ?: entry.media?.component?.packageName
-        Tile(entry.label, entry.icon, verified = pkg != null && KnownApps.works(pkg)) {
-            entry.template?.let { CarServices.connectNav(it, frame); navigator.home() }
-            entry.media?.let { CarServices.openMedia(it); navigator.media() }
-        }
+        val id = entry.componentId
+        Tile(
+            entry.label, entry.icon,
+            verified = pkg != null && KnownApps.works(pkg),
+            broken = pkg != null && KnownApps.isBroken(pkg),
+            pinned = id != null && id in pinned,
+            onLongClick = id?.let { { CarSettings.togglePin(it) } },
+        ) { launchEntry(entry, navigator, frame) }
     } + listOf(
         Tile("Settings", glyph = Icons.Filled.Settings) { navigator.settings() },
     )
@@ -164,12 +194,30 @@ private fun VerifiedBadge(size: androidx.compose.ui.unit.Dp, modifier: Modifier
     }
 }
 
+/** A red disc with a white X: marks a tile known not to work with Gearslip yet. */
+@Composable
+private fun BrokenBadge(size: androidx.compose.ui.unit.Dp, modifier: Modifier = Modifier) {
+    Box(
+        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))
+    }
+}
+
+@OptIn(ExperimentalFoundationApi::class)
 @Composable
 private fun AppTile(tile: Tile) {
+    val shape = MaterialTheme.shapes.extraLarge
     Surface(
-        onClick = tile.onClick,
-        modifier = Modifier.height(120.dp),
-        shape = MaterialTheme.shapes.extraLarge,
+        modifier = Modifier
+            .height(120.dp)
+            .let { if (tile.pinned) it.border(2.dp, MaterialTheme.colorScheme.primary, shape) else it }
+            // combinedClickable, not Surface's own onClick, so a long press can mean something
+            // different from a tap - pinning is deliberately the same gesture everywhere apps
+            // are shown (here and, once pinned, the shortcut itself on the nav bar).
+            .combinedClickable(onClick = tile.onClick, onLongClick = tile.onLongClick),
+        shape = shape,
         color = MaterialTheme.colorScheme.surfaceVariant,
         contentColor = MaterialTheme.colorScheme.onSurfaceVariant,
     ) {
@@ -196,6 +244,9 @@ private fun AppTile(tile: Tile) {
             if (tile.verified) {
                 VerifiedBadge(24.dp, Modifier.align(Alignment.TopEnd).padding(8.dp))
             }
+            if (tile.broken) {
+                BrokenBadge(24.dp, Modifier.align(Alignment.TopEnd).padding(8.dp))
+            }
         }
     }
 }

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

@@ -1,6 +1,7 @@
 package app.seb3thehacker.gearslip.car
 
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.staticCompositionLocalOf
@@ -24,58 +25,81 @@ sealed interface CarScreen {
     data class App(val id: String) : CarScreen
 }
 
+/** One step on the breadcrumb trail: the screen it shows and the word for it in the trail. */
+data class Crumb(val screen: CarScreen, val label: String)
+
 /**
- * Where the car UI is. A car touchscreen has no hardware back button, so [back] is driven by
- * the on-screen one; an open app can claim it first (a browser going back a page) through
- * [backInterceptor].
+ * Where the car UI is, and how it got there. A car touchscreen has no hardware back button, so
+ * every screen that isn't reached from [home] is pushed onto a trail (like a browser's history,
+ * or a file manager's breadcrumb bar) rather than replacing the last one outright - that's what
+ * lets the breadcrumb bar show "Home > Apps > Settings" and jump straight back to any of them,
+ * and lets [back] undo exactly one step instead of always dumping you back at Home. An open app
+ * can claim a back step first (a browser going back a page) through [backInterceptor].
  */
 class CarNavigator(startId: String) {
 
-    var current: CarScreen by mutableStateOf(
-        if (CarApps.find(startId) != null) CarScreen.App(startId) else CarScreen.Home,
+    private val stack = mutableStateListOf(
+        Crumb(
+            if (CarApps.find(startId) != null) CarScreen.App(startId) else CarScreen.Home,
+            "Home",
+        ),
     )
-        private set
+
+    /** The whole trail, root first. Size 1 means "at Home" - the breadcrumb bar hides then. */
+    val trail: List<Crumb> get() = stack
+
+    val current: CarScreen get() = stack.last().screen
 
     var backInterceptor: (() -> Boolean)? = null
 
-    fun home() { current = CarScreen.Home }
-
-    /**
-     * Minimised, the home screen's player folds into the nav bar and the map takes the width.
-     * Opening the media screen from the bar restores it, so leaving that screen lands on the
-     * home screen with the player back in place.
-     */
-    var playerMinimised by mutableStateOf(false)
-        private set
-
-    /** Set by the player's Lyrics button; the media screen reads it once when it opens. */
-    var lyricsRequested = false
-
-    fun minimisePlayer() { playerMinimised = true }
-
-    fun restorePlayer() { playerMinimised = false }
-
-    fun media(lyrics: Boolean = false) {
-        lyricsRequested = lyrics
-        playerMinimised = false
-        current = CarScreen.Media
+    /** Pushes a new step, unless it's the same screen already on top - tapping the button for
+     * where you already are shouldn't grow the trail. */
+    private fun push(screen: CarScreen, label: String) {
+        if (stack.last().screen == screen) return
+        stack.add(Crumb(screen, label))
     }
 
-    fun apps() { current = CarScreen.Apps }
+    /** The one way back to a clean slate: resets the whole trail to just Home. */
+    fun home() {
+        stack.clear()
+        stack.add(Crumb(CarScreen.Home, "Home"))
+    }
 
-    fun settings() { current = CarScreen.Settings }
+    /**
+     * The nav bar's now-playing pill is the player everywhere; this is only whether the home
+     * screen is additionally showing lyrics for it in the column beside the map. Toggled by the
+     * pill's own lyrics button, so it means the same thing wherever the pill is visible, even
+     * though only the home screen actually has the room to show it.
+     */
+    var lyricsOpen by mutableStateOf(false)
+        private set
 
-    fun dashboard() { current = CarScreen.Dashboard }
+    fun toggleLyrics() { lyricsOpen = !lyricsOpen }
 
-    fun weather() { current = CarScreen.Weather }
+    fun media() { push(CarScreen.Media, "Media") }
 
-    fun notifications(replyTo: String? = null) { current = CarScreen.Notifications(replyTo) }
+    fun apps() { push(CarScreen.Apps, "Apps") }
 
-    fun open(id: String) { current = CarScreen.App(id) }
+    fun settings() { push(CarScreen.Settings, "Settings") }
 
+    fun dashboard() { push(CarScreen.Dashboard, "Dashboard") }
+
+    fun weather() { push(CarScreen.Weather, "Weather") }
+
+    fun notifications(replyTo: String? = null) { push(CarScreen.Notifications(replyTo), "Notifications") }
+
+    fun open(id: String) { push(CarScreen.App(id), CarApps.find(id)?.label ?: id) }
+
+    /** Jumps straight to a step already on the trail, dropping everything after it - what
+     * tapping a breadcrumb does. Index 0 (Home) is always on the trail, so this always succeeds. */
+    fun jumpTo(index: Int) {
+        while (stack.size > index + 1) stack.removeAt(stack.lastIndex)
+    }
+
+    /** One step back, same as tapping the crumb before the current one. */
     fun back() {
         if (backInterceptor?.invoke() == true) return
-        current = CarScreen.Home
+        if (stack.size > 1) stack.removeAt(stack.lastIndex)
     }
 }
 

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

@@ -39,6 +39,7 @@ object CarServices {
     fun init(appContext: Context) {
         context = appContext.applicationContext
         app.seb3thehacker.gearslip.notify.CarMotion.start(appContext)
+        app.seb3thehacker.gearslip.call.CarCalls.start(appContext)
     }
 
     // --- map -----------------------------------------------------------------------------
@@ -54,6 +55,12 @@ object CarServices {
         nav.disconnect()
     }
 
+    /** Undoes [stopNav]'s hold so the last map app comes back, same as it would after a restart. */
+    suspend fun reconnectNav(frame: CarEnvironment.Frame) {
+        navStopped = false
+        autostart(frame)
+    }
+
     // --- media ---------------------------------------------------------------------------
 
     fun openMedia(app: MediaApp, autoplay: Boolean = false) {
@@ -62,11 +69,12 @@ object CarServices {
         val live = phase == CarMedia.Phase.READY || phase == CarMedia.Phase.CONNECTING
         if (_mediaApp.value?.component == app.component && live) return
 
-        CarAudio.release()
         _mediaApp.value = app
         autoplayPending = autoplay
         media.connect(app)
-        if (CarSettings.pipeAudio.value) CarAudio.request(app.uid)
+        // 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()
     }
 
     /** Called once the media app is connected: starts playback if that was asked for. */
@@ -104,6 +112,7 @@ object CarServices {
     /** The car went away: nothing should keep running for a screen that no longer exists. */
     fun shutdown() {
         context?.let { app.seb3thehacker.gearslip.notify.CarMotion.stop(it) }
+        app.seb3thehacker.gearslip.call.CarCalls.stop()
         runCatching { nav.disconnect() }
         runCatching { media.disconnect() }
         CarAudio.release()

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

@@ -24,6 +24,11 @@ object CarSettings {
     private const val KEY_LAST_MEDIA = "car_last_media"
     private const val KEY_AUTOPLAY = "car_autoplay"
     private const val KEY_THEME = "car_app_theme"
+    private const val KEY_PINNED = "car_pinned_apps"
+
+    /** How many shortcuts the nav bar makes room for; a driver reaching for one needs it to
+     * still be on the bar, not off the edge of a long list. */
+    const val MAX_PINNED = 3
 
     /** Id of the app to open on connect; [HOME] opens the launcher. */
     const val HOME = "home"
@@ -33,12 +38,16 @@ object CarSettings {
     private val scaleFlow = MutableStateFlow(1f)
     private val openFlow = MutableStateFlow(HOME)
     private val nightFlow = MutableStateFlow(NightMode.AUTO)
-    private val pipeAudioFlow = MutableStateFlow(false)
+    private val pipeAudioFlow = MutableStateFlow(true)
     private val lastNavFlow = MutableStateFlow<String?>(null)
     private val lastMediaFlow = MutableStateFlow<String?>(null)
     private val autoplayFlow = MutableStateFlow(false)
     private val themeFlow = MutableStateFlow(AppTheme.PHONE)
     val appTheme: StateFlow<AppTheme> = themeFlow
+    private val pinnedFlow = MutableStateFlow<Set<String>>(emptySet())
+
+    /** Flattened component names of the apps long-pressed onto the nav bar as shortcuts. */
+    val pinnedApps: StateFlow<Set<String>> = pinnedFlow
 
     /** Flattened component names of the map and media apps used last, brought back on connect. */
     val lastNav: StateFlow<String?> = lastNavFlow
@@ -52,9 +61,10 @@ object CarSettings {
     val nightMode: StateFlow<NightMode> = nightFlow
 
     /**
-     * Whether a media app's sound is captured and sent over the car link. Off by default: the
-     * platform only allows that behind a screen-capture consent dialog, and without it the app
-     * simply plays through the phone's normal output (e.g. Bluetooth to the car).
+     * Whether a media app's sound is captured and sent over the car link. On by default, since
+     * sound in the car is the point of the exercise; the platform allows the capture only behind a
+     * consent dialog, which [app.seb3thehacker.gearslip.audio.CarAudio] raises once the car has
+     * somewhere to play it. Turned off, the app plays through the phone's normal output instead.
      */
     val pipeAudio: StateFlow<Boolean> = pipeAudioFlow
 
@@ -68,10 +78,12 @@ object CarSettings {
             AppTheme.valueOf(AppSettings.getString(app, KEY_THEME, AppTheme.PHONE.name))
         }.getOrDefault(AppTheme.PHONE)
         autoplayFlow.value = AppSettings.getString(app, KEY_AUTOPLAY, "false") == "true"
-        pipeAudioFlow.value = AppSettings.getString(app, KEY_PIPE_AUDIO, "false") == "true"
+        pipeAudioFlow.value = AppSettings.getString(app, KEY_PIPE_AUDIO, "true") == "true"
         nightFlow.value = runCatching {
             NightMode.valueOf(AppSettings.getString(app, KEY_NIGHT, NightMode.AUTO.name))
         }.getOrDefault(NightMode.AUTO)
+        pinnedFlow.value = AppSettings.getString(app, KEY_PINNED, "")
+            .split(",").filter { it.isNotEmpty() }.toSet()
     }
 
     fun setScale(value: Float) {
@@ -114,4 +126,17 @@ object CarSettings {
         AppSettings.putString(app, KEY_NIGHT, mode.name)
         CarEnvironment.refresh()
     }
+
+    /** Long-pressed onto or off the nav bar. Silently does nothing past [MAX_PINNED] rather than
+     * bumping the oldest pin - a driver who filled the bar on purpose shouldn't lose one by accident. */
+    fun togglePin(component: String) {
+        val current = pinnedFlow.value
+        val next = when {
+            component in current -> current - component
+            current.size >= MAX_PINNED -> return
+            else -> current + component
+        }
+        pinnedFlow.value = next
+        AppSettings.putString(app, KEY_PINNED, next.joinToString(","))
+    }
 }

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

@@ -98,9 +98,10 @@ fun CarSettingsScreen() {
             pipeAudio,
         ) { CarSettings.setPipeAudio(it) }
         Text(
-            "Phone output needs no permission: the app plays as it normally would, e.g. over " +
-                "Bluetooth to the car. Through Gearslip sends the sound over the car link, and " +
-                "Android asks for screen-capture consent each time.",
+            "Through Gearslip sends the sound over the USB link. Android asks for consent the " +
+                "first time a media app plays in the car, and some apps refuse to be captured at " +
+                "all. Phone output needs no permission: the app plays as it normally would, for " +
+                "example over Bluetooth to the car.",
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
@@ -116,9 +117,6 @@ fun CarSettingsScreen() {
             Info("Video", display.ifEmpty { "-" })
             Info("Certificate", cert?.headline ?: "Checking…")
         }
-        val navigator = LocalCarNavigator.current
-        Button(onClick = { navigator.open("calibrate") }) { Text("Display test") }
-        Spacer(Modifier.height(8.dp))
     }
 }
 

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

@@ -4,6 +4,7 @@ import androidx.compose.foundation.Image
 import androidx.compose.foundation.clickable
 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
@@ -19,9 +20,10 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.background
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.filled.Home
 import androidx.compose.material.icons.filled.Notifications
 import androidx.compose.material.icons.filled.PlayArrow
-import androidx.compose.material.icons.filled.Home
 import androidx.compose.material3.FilledIconButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -44,6 +46,7 @@ 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
@@ -55,8 +58,12 @@ 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.host.CarAppConnection
 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
 
@@ -123,30 +130,29 @@ fun CarUi() {
                         end = insets.right.toDp(), bottom = insets.bottom.toDp(),
                     )
                 }
-                // The calibration screen is the raw frame: no insets, no nav bar.
                 val screen = navigator.current
-                if (screen == CarScreen.App("calibrate")) {
-                    CarApps.find("calibrate")?.content?.invoke()
-                } else {
-                    Column(Modifier.fillMaxSize().padding(pad)) {
-                        Box(Modifier.weight(1f).fillMaxWidth()) {
-                            when (screen) {
-                                CarScreen.Home -> CarHome()
-                                CarScreen.Apps -> CarLauncher()
-                                CarScreen.Media -> mediaApp?.let { MediaScreen(it) { navigator.home() } }
-                                CarScreen.Settings -> CarSettingsScreen()
-                                CarScreen.Dashboard -> CarDashboardScreen()
-                                CarScreen.Weather -> WeatherScreen()
-                                is CarScreen.Notifications -> NotificationsScreen(screen.replyTo)
-                                is CarScreen.App -> CarApps.find(screen.id)?.content?.invoke()
-                            }
-                            // The history screen is already showing them, so it needs no popup.
-                            if (screen !is CarScreen.Notifications) {
-                                NotificationPopup(Modifier.align(Alignment.TopCenter))
-                            }
+                Column(Modifier.fillMaxSize().padding(pad)) {
+                    // Header navigation (breadcrumb trail) - off for now, kept to tweak later.
+                    // BreadcrumbBar(navigator)
+                    Box(Modifier.weight(1f).fillMaxWidth()) {
+                        when (screen) {
+                            CarScreen.Home -> CarHome()
+                            CarScreen.Apps -> CarLauncher()
+                            CarScreen.Media -> mediaApp?.let { MediaScreen(it) { navigator.back() } }
+                            CarScreen.Settings -> CarSettingsScreen()
+                            CarScreen.Dashboard -> CarDashboardScreen()
+                            CarScreen.Weather -> WeatherScreen()
+                            is CarScreen.Notifications -> NotificationsScreen(screen.replyTo)
+                            is CarScreen.App -> CarApps.find(screen.id)?.content?.invoke()
                         }
-                        CarNavBar(navigator)
+                        // The history screen is already showing them, so it needs no popup.
+                        if (screen !is CarScreen.Notifications) {
+                            NotificationPopup(Modifier.align(Alignment.TopCenter))
+                        }
+                        // Above the popup: a call is more urgent than any notification.
+                        CallOverlay(Modifier.align(Alignment.TopCenter))
                     }
+                    CarNavBar(navigator)
                 }
             }
         }
@@ -154,68 +160,166 @@ fun CarUi() {
 }
 
 /**
- * Home and Apps on the left; now-playing pill in the middle; clock (tap for calendar and weather), phone battery and the
- * darkness signal on the right. Icon-only: a driver reads a glyph faster than a label, and it
- * keeps the bar short enough to leave the app underneath more room.
+ * "Home > 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,
+    ) {
+        IconButton(onClick = navigator::back, modifier = Modifier.size(36.dp)) {
+            Icon(Icons.AutoMirrored.Filled.ArrowBack, "Back", Modifier.size(20.dp))
+        }
+        Spacer(Modifier.width(2.dp))
+        trail.forEachIndexed { index, crumb ->
+            val isLast = index == trail.lastIndex
+            Text(
+                crumb.label,
+                style = MaterialTheme.typography.labelLarge,
+                fontWeight = if (isLast) FontWeight.SemiBold else FontWeight.Normal,
+                color = if (isLast) MaterialTheme.colorScheme.onSurface else MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = if (isLast) Modifier else Modifier
+                    .clip(RoundedCornerShape(6.dp))
+                    .clickable { navigator.jumpTo(index) }
+                    .padding(horizontal = 4.dp, vertical = 2.dp),
+            )
+            if (!isLast) {
+                Text(
+                    "›",
+                    style = MaterialTheme.typography.labelLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    modifier = Modifier.padding(horizontal = 2.dp),
+                )
+            }
+        }
+    }
+}
+
+/**
+ * Apps and open/pinned shortcuts on the left; now-playing pill against them; clock (tap for
+ * calendar and weather), phone battery and the darkness signal on the right. Icon-only: a driver
+ * reads a glyph faster than a label, and it keeps the bar short enough to leave the app underneath
+ * more room.
  */
 @Composable
 private fun CarNavBar(navigator: CarNavigator) {
     val battery by CarEnvironment.battery.collectAsState()
-    val darkOutside by CarEnvironment.darkOutside.collectAsState()
     val now by rememberNow()
-
-    // The home screen shows what's playing itself, unless it was minimised; everywhere else it lives in this bar.
-    val showNowPlaying = navigator.current != CarScreen.Home || navigator.playerMinimised
     val weather by Weather.state.collectAsState()
+    val weatherData = (weather as? WeatherState.Ready)?.data
+
+    // The one app that's actually open and not otherwise reachable from this bar: media has its
+    // own pill already, so the only "open app" icon worth showing is whichever map is connected.
+    val navStatus by CarServices.nav.status.collectAsState()
+    val lastNav by CarSettings.lastNav.collectAsState()
+    val openMapComponent = lastNav?.takeIf { navStatus.phase == CarAppConnection.Phase.RUNNING }
+
+    val context = LocalContext.current
+    val pinnedIds by CarSettings.pinnedApps.collectAsState()
+    val entries by produceState(LauncherCache.entries ?: emptyList(), context) {
+        value = LauncherCache.entries ?: withContext(Dispatchers.IO) { LauncherCache.load(context) }
+    }
+    val pinnedEntries = remember(entries, pinnedIds) {
+        pinnedIds.mapNotNull { id -> entries.find { it.componentId == id } }
+    }
+    val frame by CarEnvironment.frame.collectAsState()
 
-    // One row, so nothing can sit on top of anything else: the player takes whatever width the
-    // fixed items leave and shortens its title to fit.
     Surface(color = MaterialTheme.colorScheme.surfaceContainer) {
-        Row(
-            Modifier.fillMaxWidth().height(56.dp).padding(horizontal = 10.dp),
-            verticalAlignment = Alignment.CenterVertically,
-        ) {
-            NavItem(Icons.Filled.Home, navigator.current == CarScreen.Home) { navigator.home() }
-            Spacer(Modifier.width(6.dp))
-            NavItem(MediaIcons.Apps, navigator.current == CarScreen.Apps) { navigator.apps() }
+        BoxWithConstraints(Modifier.fillMaxWidth().height(56.dp).padding(horizontal = 10.dp)) {
+            Row(Modifier.fillMaxSize(), verticalAlignment = Alignment.CenterVertically) {
+                // Home and Apps are two different places now, not a toggle on one button - the
+                // breadcrumb trail is how you retrace your steps, but reaching for either of
+                // these two from three screens deep in a media app shouldn't mean reading it
+                // first.
+                NavItem(Icons.Filled.Home, navigator.current == CarScreen.Home) { navigator.home() }
+                Spacer(Modifier.width(6.dp))
+                NavItem(MediaIcons.Apps, navigator.current == CarScreen.Apps) { navigator.apps() }
 
-            Box(Modifier.weight(1f).padding(horizontal = 10.dp), contentAlignment = Alignment.CenterStart) {
-                if (showNowPlaying) NavNowPlaying(navigator, selected = navigator.current == CarScreen.Media)
-            }
-
-            (weather as? WeatherState.Ready)?.data?.let { w ->
-                NavChip(navigator.current == CarScreen.Weather, { navigator.weather() }) {
-                    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(6.dp)) {
-                        WeatherIcon(w.code, w.isDay, size = 28.dp)
-                        Text("${w.temp}°", style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+                openMapComponent?.let { component ->
+                    Spacer(Modifier.width(6.dp))
+                    NavAppIcon(component, contentDescription = "Map", onClick = navigator::home)
+                }
+                pinnedEntries.forEach { entry ->
+                    Spacer(Modifier.width(6.dp))
+                    entry.componentId?.let { id ->
+                        NavAppIcon(id, contentDescription = entry.label) { launchEntry(entry, navigator, frame) }
                     }
                 }
-                Spacer(Modifier.width(4.dp))
-            }
-            NavChip(navigator.current == CarScreen.Dashboard, { navigator.dashboard() }) {
-                Column(horizontalAlignment = Alignment.End) {
-                    Text(
-                        DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(now)),
-                        style = MaterialTheme.typography.titleMedium,
-                        fontWeight = FontWeight.SemiBold,
-                    )
-                    val phone = if (battery.percent >= 0) "${battery.percent}%${if (battery.charging) " charging" else ""}" else ""
-                    val light = if (darkOutside) "Night" else "Day"
-                    Text(
-                        listOf(phone, light).filter { it.isNotEmpty() }.joinToString("  ·  "),
-                        style = MaterialTheme.typography.labelMedium,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    )
+
+                Box(Modifier.weight(1f).padding(horizontal = 10.dp), contentAlignment = Alignment.CenterStart) {
+                    NavNowPlaying(navigator, selected = navigator.current == CarScreen.Media)
                 }
+
+                // Weather no longer has its own chip - the temperature alone (no icon, no room
+                // for one) sits where "Night"/"Day" used to, freeing a whole chip's width for the
+                // Home button above.
+                NavChip(navigator.current == CarScreen.Dashboard, { navigator.dashboard() }) {
+                    Column(horizontalAlignment = Alignment.End) {
+                        Text(
+                            DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(now)),
+                            style = MaterialTheme.typography.titleMedium,
+                            fontWeight = FontWeight.SemiBold,
+                        )
+                        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(3.dp)) {
+                            if (battery.percent >= 0) {
+                                Text(
+                                    "${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,
+                                )
+                            }
+                        }
+                    }
+                }
+                Spacer(Modifier.width(10.dp))
+                NavItem(
+                    Icons.Filled.Notifications, navigator.current is CarScreen.Notifications, padding = 8.dp,
+                ) { navigator.notifications() }
             }
-            Spacer(Modifier.width(10.dp))
-            NavItem(
-                Icons.Filled.Notifications, navigator.current is CarScreen.Notifications,
-            ) { navigator.notifications() }
         }
     }
 }
 
+/** One open or pinned app's icon on the nav bar - the same fixed size and shape either way. */
+@Composable
+private fun NavAppIcon(component: String, contentDescription: String?, onClick: () -> Unit) {
+    val context = LocalContext.current
+    val pkg = remember(component) { android.content.ComponentName.unflattenFromString(component)?.packageName }
+    val icon by produceState<androidx.compose.ui.graphics.ImageBitmap?>(null, pkg) {
+        value = pkg?.let {
+            runCatching { context.packageManager.getApplicationIcon(it).toBitmap(96, 96).asImageBitmap() }.getOrNull()
+        }
+    }
+    Box(
+        Modifier
+            .size(44.dp)
+            .clip(RoundedCornerShape(14.dp))
+            .background(MaterialTheme.colorScheme.surfaceVariant)
+            .clickable(onClick = onClick),
+        contentAlignment = Alignment.Center,
+    ) {
+        icon?.let { Image(it, contentDescription, Modifier.size(30.dp).clip(RoundedCornerShape(8.dp))) }
+    }
+}
+
 /** A tappable group in the bar that stays highlighted while its screen is open, like [NavItem]. */
 @Composable
 private fun NavChip(selected: Boolean, onClick: () -> Unit, content: @Composable () -> Unit) {
@@ -231,14 +335,14 @@ private fun NavChip(selected: Boolean, onClick: () -> Unit, content: @Composable
 }
 
 @Composable
-private fun NavItem(icon: ImageVector, selected: Boolean, onClick: () -> Unit) {
+private fun NavItem(icon: ImageVector, selected: Boolean, padding: androidx.compose.ui.unit.Dp = 12.dp, onClick: () -> Unit) {
     val scheme = MaterialTheme.colorScheme
     Box(
         Modifier
             .clip(RoundedCornerShape(18.dp))
             .background(if (selected) scheme.secondaryContainer else scheme.surfaceContainer)
             .clickable(onClick = onClick)
-            .padding(12.dp),
+            .padding(padding),
         contentAlignment = Alignment.Center,
     ) {
         Icon(icon, contentDescription = null, modifier = Modifier.size(28.dp))
@@ -254,7 +358,11 @@ internal fun rememberNow(): State<Long> = produceState(System.currentTimeMillis(
     }
 }
 
-/** Art, title and play/pause in the nav bar; tapping the art or title opens the full media screen. */
+/**
+ * The one persistent player, everywhere - not just a Home-screen extra. Art and title open the
+ * full media screen; skip and play/pause work right here; the last button toggles the lyrics
+ * panel beside the map on Home (see [CarHome]), the pill's own lyrics affordance wherever it sits.
+ */
 @Composable
 private fun NavNowPlaying(navigator: CarNavigator, selected: Boolean, modifier: Modifier = Modifier) {
     val media = CarServices.media
@@ -302,9 +410,65 @@ private fun NavNowPlaying(navigator: CarNavigator, selected: Boolean, modifier:
                 Modifier.size(26.dp),
             )
         }
-        IconButton(onClick = { media.next() }, modifier = Modifier.size(44.dp)) {
-            Icon(MediaIcons.Next, "Next", Modifier.size(28.dp))
+        FilledIconButton(
+            onClick = navigator::toggleLyrics,
+            modifier = Modifier.size(44.dp),
+            colors = androidx.compose.material3.IconButtonDefaults.filledIconButtonColors(
+                containerColor = if (navigator.lyricsOpen) MaterialTheme.colorScheme.primary
+                else MaterialTheme.colorScheme.surfaceContainerHighest,
+                contentColor = if (navigator.lyricsOpen) MaterialTheme.colorScheme.onPrimary
+                else MaterialTheme.colorScheme.onSurfaceVariant,
+            ),
+        ) {
+            LyricsGlyph(Modifier.size(22.dp))
         }
     }
     }
 }
+
+/**
+ * A card with two lines of text on it - read as "lyrics"/"captions" at a glance, which no icon in
+ * the core Material set does (the closest, a bullet list, reads as a menu, not song text). Drawn
+ * rather than a vector asset since the whole glyph is two shapes.
+ */
+@Composable
+private fun LyricsGlyph(modifier: Modifier = Modifier) {
+    val tint = androidx.compose.material3.LocalContentColor.current
+    androidx.compose.foundation.Canvas(modifier) {
+        val stroke = size.minDimension * 0.11f
+        drawRoundRect(
+            color = tint,
+            cornerRadius = androidx.compose.ui.geometry.CornerRadius(size.minDimension * 0.22f),
+            style = androidx.compose.ui.graphics.drawscope.Stroke(width = stroke),
+        )
+        val lineStyle = androidx.compose.ui.graphics.drawscope.Stroke(width = stroke * 0.85f, cap = androidx.compose.ui.graphics.StrokeCap.Round)
+        val startX = size.width * 0.24f
+        listOf(0.40f, 0.64f).forEach { fy ->
+            val endX = size.width * (if (fy < 0.5f) 0.76f else 0.62f)
+            drawLine(tint, androidx.compose.ui.geometry.Offset(startX, size.height * fy), androidx.compose.ui.geometry.Offset(endX, size.height * fy), strokeWidth = lineStyle.width, cap = lineStyle.cap)
+        }
+    }
+}
+
+/**
+ * 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 the same way [LyricsGlyph] is.
+ */
+@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/MediaScreen.kt

@@ -2,10 +2,13 @@ package app.seb3thehacker.gearslip.car
 
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
 import androidx.compose.foundation.layout.Arrangement
 import android.provider.Settings
 import android.content.Intent
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -62,6 +65,7 @@ import app.seb3thehacker.gearslip.media.LyricsResult
 import app.seb3thehacker.gearslip.media.Lyrics
 import app.seb3thehacker.gearslip.media.MediaEntry
 import app.seb3thehacker.gearslip.media.NowPlaying
+import app.seb3thehacker.gearslip.media.QueueTrack
 import android.media.session.PlaybackState
 
 /**
@@ -74,13 +78,11 @@ fun MediaScreen(app: MediaApp, onExit: () -> Unit) {
     val media = CarServices.media
     val phase by media.phase.collectAsStateWithLifecycle()
     val now by media.now.collectAsStateWithLifecycle()
+    val queue by media.queue.collectAsStateWithLifecycle()
     val browse by media.browse.collectAsStateWithLifecycle()
     val rejection by media.rejection.collectAsStateWithLifecycle()
     val capture by CarAudio.capture.collectAsStateWithLifecycle()
-    val navigator = LocalCarNavigator.current
-    var tab by remember {
-        mutableStateOf(if (navigator.lyricsRequested) Tab.LYRICS else Tab.BROWSE).also { navigator.lyricsRequested = false }
-    }
+    var tab by remember { mutableStateOf(Tab.NOW_PLAYING) }
 
     // The connection outlives this screen: the home screen's player is the same one.
     LaunchedEffect(app) { CarServices.openMedia(app) }
@@ -118,19 +120,27 @@ fun MediaScreen(app: MediaApp, onExit: () -> Unit) {
                 Modifier.fillMaxSize().padding(top = 6.dp),
                 horizontalArrangement = Arrangement.spacedBy(16.dp),
             ) {
-                NowPlayingPanel(now, media, Modifier.width(250.dp).fillMaxHeight())
+                // The art rail sits at the top, level with the tab row beside it, on every tab -
+                // not under a full-width tab bar the way it used to be. Transport and the
+                // progress bar stay on it always; only the app's extra buttons (shuffle, repeat,
+                // like) are exclusive to the "Now playing" tab's own content area, since those are
+                // the one thing that isn't already always visible here.
+                NowPlayingRail(now, media, Modifier.width(220.dp).fillMaxHeight())
                 Column(Modifier.weight(1f).fillMaxHeight()) {
-                    Row {
-                        TextButton(onClick = { tab = Tab.BROWSE }) {
-                            Text("Browse", fontWeight = if (tab == Tab.BROWSE) FontWeight.Bold else FontWeight.Normal)
-                        }
-                        TextButton(onClick = { tab = Tab.LYRICS }) {
-                            Text("Lyrics", fontWeight = if (tab == Tab.LYRICS) FontWeight.Bold else FontWeight.Normal)
-                        }
+                    Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+                        MediaTab("Now playing", tab == Tab.NOW_PLAYING, Modifier.weight(1f)) { tab = Tab.NOW_PLAYING }
+                        MediaTab("Browse", tab == Tab.BROWSE, Modifier.weight(1f)) { tab = Tab.BROWSE }
+                        MediaTab("Up next", tab == Tab.QUEUE, Modifier.weight(1f)) { tab = Tab.QUEUE }
+                        MediaTab("Lyrics", tab == Tab.LYRICS, Modifier.weight(1f)) { tab = Tab.LYRICS }
                     }
-                    when (tab) {
-                        Tab.BROWSE -> BrowsePanel(browse, media, app.label, Modifier.fillMaxSize())
-                        Tab.LYRICS -> LyricsPanel(now, Modifier.fillMaxSize())
+                    Spacer(Modifier.height(8.dp))
+                    Box(Modifier.weight(1f).fillMaxWidth()) {
+                        when (tab) {
+                            Tab.NOW_PLAYING -> NowPlayingExtras(now, media, Modifier.fillMaxSize())
+                            Tab.BROWSE -> BrowsePanel(browse, media, app.label, Modifier.fillMaxSize())
+                            Tab.QUEUE -> QueuePanel(queue, now, media, Modifier.fillMaxSize())
+                            Tab.LYRICS -> LyricsPanel(now, Modifier.fillMaxSize())
+                        }
                     }
                 }
             }
@@ -138,14 +148,30 @@ fun MediaScreen(app: MediaApp, onExit: () -> Unit) {
     }
 }
 
-private enum class Tab { BROWSE, LYRICS }
+private enum class Tab { NOW_PLAYING, BROWSE, QUEUE, LYRICS }
+
+/** A bigger, easier-to-hit tab than a plain [TextButton] - this row is the only navigation on the screen. */
+@Composable
+private fun MediaTab(label: String, selected: Boolean, modifier: Modifier, onClick: () -> Unit) {
+    Surface(
+        onClick = onClick,
+        modifier = modifier.height(48.dp),
+        shape = MaterialTheme.shapes.large,
+        color = if (selected) MaterialTheme.colorScheme.primaryContainer else MaterialTheme.colorScheme.surfaceContainerHigh,
+        contentColor = if (selected) MaterialTheme.colorScheme.onPrimaryContainer else MaterialTheme.colorScheme.onSurface,
+    ) {
+        Row(Modifier.fillMaxSize(), horizontalArrangement = Arrangement.Center, verticalAlignment = Alignment.CenterVertically) {
+            Text(label, style = MaterialTheme.typography.titleMedium, fontWeight = if (selected) FontWeight.Bold else FontWeight.Normal)
+        }
+    }
+}
 
 /**
  * The song's lyrics, fetched when this tab opens. Synced lyrics follow the playback position with
  * the current line in the accent colour; unsynced ones are plain scrolling text.
  */
 @Composable
-private fun LyricsPanel(now: NowPlaying, modifier: Modifier) {
+internal fun LyricsPanel(now: NowPlaying, modifier: Modifier) {
     val lyrics by produceState<LyricsState>(LyricsState.Loading, now.title, now.artist, now.album, now.durationMs) {
         value = LyricsState.Loading
         value = Lyrics.find(now.title, now.artist, now.album, now.durationMs)
@@ -230,10 +256,24 @@ private fun Notice(title: String, detail: String?, action: Pair<String, () -> Un
     }
 }
 
+/** "1:05" for under a minute past the hour, "1:01:05" once an hour is involved. */
+private fun formatDuration(ms: Long): String {
+    val totalSeconds = (ms / 1000).coerceAtLeast(0)
+    val hours = totalSeconds / 3600
+    val minutes = (totalSeconds % 3600) / 60
+    val seconds = totalSeconds % 60
+    return if (hours > 0) "%d:%02d:%02d".format(hours, minutes, seconds) else "%d:%02d".format(minutes, seconds)
+}
+
 // --- now playing -----------------------------------------------------------------------------
 
+/**
+ * The art rail beside every tab: art, title, transport and the seek bar - always visible no
+ * matter which tab is open. Only the app's extra buttons (shuffle, repeat, like) are held back
+ * for [NowPlayingExtras], since those are the one thing that isn't already always shown here.
+ */
 @Composable
-private fun NowPlayingPanel(now: NowPlaying, media: CarMedia, modifier: Modifier) {
+private fun NowPlayingRail(now: NowPlaying, media: CarMedia, modifier: Modifier) {
     val context = LocalContext.current
     val art by produceState(now.art, now.art, now.artUri) {
         value = now.art ?: MediaArt.load(context, now.artUri)
@@ -246,55 +286,76 @@ private fun NowPlayingPanel(now: NowPlaying, media: CarMedia, modifier: Modifier
         }
     }
 
-    Column(modifier, horizontalAlignment = Alignment.CenterHorizontally) {
-        Surface(
-            shape = MaterialTheme.shapes.large,
-            color = MaterialTheme.colorScheme.surfaceVariant,
-            modifier = Modifier.size(170.dp),
-        ) {
-            art?.let {
-                Image(it.asImageBitmap(), null, Modifier.fillMaxSize().clip(MaterialTheme.shapes.large), contentScale = ContentScale.Crop)
+    // Whether the progress bar (and its duration text) is showing depends on whether the app has
+    // reported a duration yet, which can arrive a beat after everything else - so this rail's
+    // content height isn't fixed. A plain fillMaxHeight Column just clips whatever doesn't fit
+    // once that row appears; scrolling means it's always reachable instead.
+    BoxWithConstraints(modifier) {
+        // Off the space actually available rather than a fixed dp value, so it doesn't overrun a
+        // short car frame the way a flat size did on anything shorter than a phone screen.
+        val artSize = minOf(maxWidth, maxHeight * 0.45f).coerceAtLeast(96.dp)
+        Column(Modifier.verticalScroll(rememberScrollState())) {
+            Surface(
+                shape = MaterialTheme.shapes.large,
+                color = MaterialTheme.colorScheme.surfaceVariant,
+                modifier = Modifier.size(artSize),
+            ) {
+                art?.let {
+                    Image(it.asImageBitmap(), null, Modifier.fillMaxSize().clip(MaterialTheme.shapes.large), contentScale = ContentScale.Crop)
+                }
             }
-        }
-        Spacer(Modifier.height(8.dp))
-        Text(
-            now.title.ifEmpty { "Nothing playing" },
-            style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
-            maxLines = 1, overflow = TextOverflow.Ellipsis,
-        )
-        Text(
-            listOf(now.artist, now.album).filter { it.isNotEmpty() }.joinToString(" - "),
-            style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant,
-            maxLines = 1, overflow = TextOverflow.Ellipsis,
-        )
-        now.error?.let { Text(it, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.error, maxLines = 2) }
-
-        if (now.durationMs > 0) {
-            WavyProgress(
-                fraction = position.toFloat() / now.durationMs,
-                playing = now.state == PlaybackState.STATE_PLAYING,
-                onSeek = { media.seek((it * now.durationMs).toLong()) },
-                modifier = Modifier.padding(vertical = 4.dp),
+            Spacer(Modifier.height(16.dp))
+            Text(
+                now.title.ifEmpty { "Nothing playing" },
+                style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.Bold,
+                maxLines = 2, overflow = TextOverflow.Ellipsis,
             )
-        } else {
-            Spacer(Modifier.height(14.dp))
-        }
+            Text(
+                listOf(now.artist, now.album).filter { it.isNotEmpty() }.joinToString(" - "),
+                style = MaterialTheme.typography.bodyLarge, color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1, overflow = TextOverflow.Ellipsis,
+            )
+            now.error?.let { Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.error, maxLines = 2) }
+            Spacer(Modifier.height(16.dp))
 
-        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(8.dp)) {
-            IconButton(onClick = media::previous, enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_PREVIOUS), modifier = Modifier.size(56.dp)) {
-                Icon(MediaIcons.Previous, "Previous", Modifier.size(32.dp))
+            if (now.durationMs > 0) {
+                WavyProgress(
+                    fraction = position.toFloat() / now.durationMs,
+                    playing = now.state == PlaybackState.STATE_PLAYING,
+                    onSeek = { media.seek((it * now.durationMs).toLong()) },
+                    modifier = Modifier.fillMaxWidth().padding(vertical = 4.dp),
+                )
+                Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceBetween) {
+                    Text(formatDuration(position), style = MaterialTheme.typography.labelMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                    Text(formatDuration(now.durationMs), style = MaterialTheme.typography.labelMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                }
+                Spacer(Modifier.height(12.dp))
             }
-            FilledIconButton(onClick = media::togglePlay, modifier = Modifier.size(68.dp)) {
-                Icon(if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow, if (now.playing) "Pause" else "Play", Modifier.size(40.dp))
-            }
-            IconButton(onClick = media::next, enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_NEXT), modifier = Modifier.size(56.dp)) {
-                Icon(MediaIcons.Next, "Next", Modifier.size(32.dp))
+
+            Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+                IconButton(onClick = media::previous, enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_PREVIOUS), modifier = Modifier.size(56.dp)) {
+                    Icon(MediaIcons.Previous, "Previous", Modifier.size(32.dp))
+                }
+                FilledIconButton(onClick = media::togglePlay, modifier = Modifier.size(68.dp)) {
+                    Icon(if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow, if (now.playing) "Pause" else "Play", Modifier.size(40.dp))
+                }
+                IconButton(onClick = media::next, enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_NEXT), modifier = Modifier.size(56.dp)) {
+                    Icon(MediaIcons.Next, "Next", Modifier.size(32.dp))
+                }
             }
         }
+    }
+}
 
-        // Whatever extra buttons the app publishes (shuffle, repeat, like), by name: their
-        // icons are resources inside the app's own package.
-        Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+/**
+ * The "Now playing" tab's own content: just the app's extra buttons (shuffle, repeat, like), by
+ * name - their icons are resources inside the app's own package, so there's nothing to draw but
+ * the label. Transport and progress already live on [NowPlayingRail], visible on every tab.
+ */
+@Composable
+private fun NowPlayingExtras(now: NowPlaying, media: CarMedia, modifier: Modifier) {
+    Column(modifier, verticalArrangement = Arrangement.Center) {
+        Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
             now.custom.take(3).forEach { action ->
                 TextButton(onClick = { media.custom(action) }) { Text(action.name, maxLines = 1, overflow = TextOverflow.Ellipsis) }
             }
@@ -307,15 +368,22 @@ private fun NowPlayingPanel(now: NowPlaying, media: CarMedia, modifier: Modifier
 @Composable
 private fun BrowsePanel(browse: app.seb3thehacker.gearslip.media.BrowseState, media: CarMedia, appLabel: String, modifier: Modifier) {
     Column(modifier) {
-        Row(verticalAlignment = Alignment.CenterVertically) {
-            if (media.canGoUp) {
-                IconButton(onClick = media::up) { Icon(Icons.Filled.ArrowBack, "Up") }
+        // At the library root there's no trail and nowhere to go up to, so there's nothing this
+        // row could say that the app's name in the top-left corner hasn't already - showing it
+        // again here (as "Browse", or as the app's own name) was just the same label twice.
+        if (media.canGoUp || browse.trail.isNotEmpty()) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                if (media.canGoUp) {
+                    IconButton(onClick = media::up) { Icon(Icons.Filled.ArrowBack, "Up") }
+                }
+                browse.trail.lastOrNull()?.let {
+                    Text(
+                        it,
+                        style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
+                        maxLines = 1, overflow = TextOverflow.Ellipsis,
+                    )
+                }
             }
-            Text(
-                browse.trail.lastOrNull() ?: "Browse",
-                style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
-                maxLines = 1, overflow = TextOverflow.Ellipsis,
-            )
         }
         when {
             browse.loading -> Notice("Loading…", null)
@@ -332,6 +400,61 @@ private fun BrowsePanel(browse: app.seb3thehacker.gearslip.media.BrowseState, me
     }
 }
 
+// --- up next -----------------------------------------------------------------------------------
+
+/**
+ * Whatever the app has queued up, starting right after the track that's playing now - not the
+ * whole queue from the top, which would just repeat what [NowPlayingRail] already shows. Apps
+ * that never publish a queue (many don't) show an empty notice rather than a permanently blank tab.
+ */
+@Composable
+private fun QueuePanel(queue: List<QueueTrack>, now: NowPlaying, media: CarMedia, modifier: Modifier) {
+    val upNext = remember(queue, now.activeQueueItemId) {
+        val current = queue.indexOfFirst { it.queueId == now.activeQueueItemId }
+        if (current >= 0) queue.drop(current + 1) else queue
+    }
+    Column(modifier) {
+        if (upNext.isEmpty()) {
+            Notice(
+                "Nothing queued.",
+                "${if (now.title.isEmpty()) "Nothing playing" else "Only what's already playing"} - " +
+                    "not every app tells Gearslip what comes next.",
+            )
+        } else {
+            LazyColumn(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                items(upNext, key = { it.queueId }) { track -> QueueRow(track, media) }
+            }
+        }
+    }
+}
+
+@Composable
+private fun QueueRow(track: QueueTrack, media: CarMedia) {
+    val context = LocalContext.current
+    val icon by produceState(track.iconBitmap, track.iconUri) {
+        value = track.iconBitmap ?: MediaArt.load(context, track.iconUri)
+    }
+    Surface(
+        onClick = { media.playQueueItem(track) },
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceVariant,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(Modifier.padding(10.dp), verticalAlignment = Alignment.CenterVertically) {
+            Box(Modifier.size(52.dp).clip(MaterialTheme.shapes.medium).background(MaterialTheme.colorScheme.surface)) {
+                icon?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
+            }
+            Column(Modifier.weight(1f).padding(horizontal = 12.dp)) {
+                Text(track.title, style = MaterialTheme.typography.titleSmall, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                if (track.subtitle.isNotEmpty()) {
+                    Text(track.subtitle, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                }
+            }
+            Icon(Icons.Filled.PlayArrow, "Play", tint = MaterialTheme.colorScheme.onSurfaceVariant)
+        }
+    }
+}
+
 @Composable
 private fun EntryRow(entry: MediaEntry, media: CarMedia) {
     val context = LocalContext.current

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

@@ -0,0 +1,374 @@
+package app.seb3thehacker.gearslip.car
+
+import android.Manifest
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.net.Uri
+import android.provider.ContactsContract
+import android.provider.Settings
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Call
+import androidx.compose.material3.Button
+import androidx.compose.material3.FilledIconButton
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+
+/** A phone contact with at least one number, as read off the device's contacts. */
+private data class Contact(val name: String, val number: String)
+
+private val CALL_PERMISSIONS = arrayOf(Manifest.permission.CALL_PHONE, Manifest.permission.READ_CONTACTS)
+
+private fun hasCallPermissions(context: Context): Boolean =
+    CALL_PERMISSIONS.all { context.checkSelfPermission(it) == PackageManager.PERMISSION_GRANTED }
+
+private fun loadContacts(context: Context): List<Contact> {
+    if (context.checkSelfPermission(Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) return emptyList()
+    val out = mutableListOf<Contact>()
+    val projection = arrayOf(
+        ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME,
+        ContactsContract.CommonDataKinds.Phone.NUMBER,
+    )
+    context.contentResolver.query(
+        ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
+        projection, null, null,
+        "${ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME} ASC",
+    )?.use { cursor ->
+        val nameIndex = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME)
+        val numberIndex = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER)
+        while (cursor.moveToNext()) {
+            val name = cursor.getString(nameIndex) ?: continue
+            val number = cursor.getString(numberIndex) ?: continue
+            out += Contact(name, number)
+        }
+    }
+    return out.distinctBy { it.number }
+}
+
+private fun placeCall(context: Context, number: String) {
+    if (number.isBlank()) return
+    if (context.checkSelfPermission(Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) return
+    runCatching {
+        context.startActivity(
+            Intent(Intent.ACTION_CALL, Uri.parse("tel:${Uri.encode(number)}")).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
+        )
+    }
+}
+
+private const val TAB_CONTACTS = 0
+private const val TAB_KEYPAD = 1
+
+/** Dialing a number or calling a contact from the car screen: a contacts tab and a keypad tab. */
+@Composable
+fun PhoneDialerScreen() {
+    val context = LocalContext.current
+    val hasPermissions = hasCallPermissions(context)
+    var tab by remember { mutableStateOf(TAB_CONTACTS) }
+
+    Column(Modifier.fillMaxSize().padding(16.dp), verticalArrangement = Arrangement.spacedBy(16.dp)) {
+        Text(
+            "Phone",
+            style = MaterialTheme.typography.headlineSmall,
+            fontWeight = FontWeight.Bold,
+            modifier = Modifier.padding(vertical = 4.dp),
+        )
+
+        if (!hasPermissions) {
+            MissingPermission(context)
+            return@Column
+        }
+
+        Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+            DialerTab("Contacts", tab == TAB_CONTACTS, Modifier.weight(1f)) { tab = TAB_CONTACTS }
+            DialerTab("Keypad", tab == TAB_KEYPAD, Modifier.weight(1f)) { tab = TAB_KEYPAD }
+        }
+
+        Box(Modifier.weight(1f).fillMaxWidth()) {
+            if (tab == TAB_CONTACTS) ContactsList(context) else Keypad(context)
+        }
+    }
+}
+
+@Composable
+private fun MissingPermission(context: Context) {
+    Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
+        Text(
+            "Gearslip needs the Phone and Contacts permissions to dial from here. Grant them " +
+                "from the app's settings.",
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+        FilledTonalButton(onClick = {
+            context.startActivity(
+                Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", context.packageName, null)),
+            )
+        }) { Text("Open app settings") }
+    }
+}
+
+@Composable
+private fun DialerTab(label: String, selected: Boolean, modifier: Modifier, onClick: () -> Unit) {
+    Surface(
+        onClick = onClick,
+        modifier = modifier.height(52.dp),
+        shape = MaterialTheme.shapes.large,
+        color = if (selected) MaterialTheme.colorScheme.primaryContainer else MaterialTheme.colorScheme.surfaceContainerHigh,
+        contentColor = if (selected) MaterialTheme.colorScheme.onPrimaryContainer else MaterialTheme.colorScheme.onSurface,
+    ) {
+        Row(Modifier.fillMaxSize(), horizontalArrangement = Arrangement.Center, verticalAlignment = Alignment.CenterVertically) {
+            Text(label, style = MaterialTheme.typography.titleMedium, fontWeight = if (selected) FontWeight.Bold else FontWeight.Normal)
+        }
+    }
+}
+
+/**
+ * A 3-column digit grid beside a fourth column holding backspace and call, stacked - four equal
+ * columns in all. Every row and both side buttons take an equal weighted share of whatever height
+ * is available, so this fits the car's short landscape frame without scrolling instead of
+ * overflowing off the bottom the way fixed-height rows did.
+ */
+@Composable
+private fun Keypad(context: Context) {
+    var number by remember { mutableStateOf("") }
+    val rows = listOf(
+        listOf("1", "2", "3"),
+        listOf("4", "5", "6"),
+        listOf("7", "8", "9"),
+        listOf("*", "0", "#"),
+    )
+
+    Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(12.dp)) {
+        Text(
+            number.ifEmpty { "Enter a number" },
+            style = MaterialTheme.typography.headlineSmall,
+            color = if (number.isEmpty()) MaterialTheme.colorScheme.onSurfaceVariant else MaterialTheme.colorScheme.onSurface,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.padding(vertical = 6.dp),
+        )
+        Row(Modifier.weight(1f).fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+            Column(Modifier.weight(3f).fillMaxHeight(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                rows.forEach { row ->
+                    Row(Modifier.weight(1f).fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                        row.forEach { digit ->
+                            KeypadButton(digit, Modifier.weight(1f).fillMaxHeight()) { number += digit }
+                        }
+                    }
+                }
+            }
+            Column(Modifier.weight(1f).fillMaxHeight(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                FilledTonalButton(
+                    onClick = { if (number.isNotEmpty()) number = number.dropLast(1) },
+                    enabled = number.isNotEmpty(),
+                    modifier = Modifier.weight(1f).fillMaxWidth(),
+                ) { Text("⌫") }
+                FilledIconButton(
+                    onClick = { placeCall(context, number) },
+                    enabled = number.isNotEmpty(),
+                    modifier = Modifier.weight(1f).fillMaxWidth(),
+                    colors = androidx.compose.material3.IconButtonDefaults.filledIconButtonColors(
+                        containerColor = MaterialTheme.colorScheme.primary,
+                        contentColor = MaterialTheme.colorScheme.onPrimary,
+                    ),
+                ) { Icon(Icons.Filled.Call, "Call") }
+            }
+        }
+    }
+}
+
+@Composable
+private fun KeypadButton(digit: String, modifier: Modifier, onClick: () -> Unit) {
+    Surface(
+        onClick = onClick,
+        modifier = modifier,
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+    ) {
+        Row(Modifier.fillMaxSize(), horizontalArrangement = Arrangement.Center, verticalAlignment = Alignment.CenterVertically) {
+            Text(digit, style = MaterialTheme.typography.titleLarge)
+        }
+    }
+}
+
+@Composable
+private fun ContactsList(context: Context) {
+    val contacts by produceState(emptyList<Contact>(), context) {
+        value = withContext(Dispatchers.IO) { loadContacts(context) }
+    }
+    var query by remember { mutableStateOf("") }
+    var searching by remember { mutableStateOf(false) }
+    var pendingCall by remember { mutableStateOf<Contact?>(null) }
+
+    val filtered = remember(contacts, query) {
+        if (query.isBlank()) contacts
+        else contacts.filter { it.name.contains(query, ignoreCase = true) || it.number.contains(query) }
+    }
+
+    Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+        if (contacts.isNotEmpty()) {
+            ContactSearchField(query, searching, onToggle = { searching = !searching })
+        }
+        // The list (and its empty states) sit between the search field and the keyboard, never
+        // under either - the keyboard is docked at the bottom instead of jammed in right below
+        // the field, so results stay visible while typing rather than getting squeezed out.
+        Box(Modifier.weight(1f).fillMaxWidth()) {
+            when {
+                contacts.isEmpty() -> Text(
+                    "No contacts with a phone number found.",
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                filtered.isEmpty() -> Text(
+                    "No contacts match \"$query\".",
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                else -> LazyColumn(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                    items(filtered) { contact ->
+                        ContactRow(contact) { pendingCall = contact }
+                    }
+                }
+            }
+        }
+        if (searching) {
+            CarKeyboard(query, onTextChange = { query = it }, onSubmit = { searching = false })
+        }
+    }
+
+    pendingCall?.let { contact ->
+        ConfirmCallOverlay(
+            contact = contact,
+            onConfirm = { placeCall(context, contact.number); pendingCall = null },
+            onDismiss = { pendingCall = null },
+        )
+    }
+}
+
+/**
+ * A plain Compose overlay, not [androidx.compose.material3.AlertDialog] - that opens a real
+ * Android Dialog/window, and this UI lives in a Presentation on a virtual display where a second
+ * window of the wrong type crashes outright ("Window type mismatch"). Every other popup in the
+ * car UI is drawn in-composition for the same reason; this just follows suit.
+ */
+@Composable
+private fun ConfirmCallOverlay(contact: Contact, onConfirm: () -> Unit, onDismiss: () -> Unit) {
+    Box(
+        Modifier.fillMaxSize().background(Color.Black.copy(alpha = 0.6f)).clickable(
+            indication = null,
+            interactionSource = remember { MutableInteractionSource() },
+            onClick = onDismiss,
+        ),
+        contentAlignment = Alignment.Center,
+    ) {
+        Surface(
+            onClick = {},
+            shape = MaterialTheme.shapes.extraLarge,
+            color = MaterialTheme.colorScheme.surfaceContainerHigh,
+            modifier = Modifier.fillMaxWidth(0.85f).padding(16.dp),
+        ) {
+            Column(
+                Modifier.padding(32.dp),
+                verticalArrangement = Arrangement.spacedBy(20.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+            ) {
+                Text("Call ${contact.name}?", style = MaterialTheme.typography.headlineSmall, fontWeight = FontWeight.Bold)
+                Text(contact.number, style = MaterialTheme.typography.titleLarge, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+                    OutlinedButton(onClick = onDismiss, modifier = Modifier.weight(1f).height(56.dp)) {
+                        Text("Cancel", style = MaterialTheme.typography.titleMedium)
+                    }
+                    Button(onClick = onConfirm, modifier = Modifier.weight(1f).height(56.dp)) {
+                        Text("Call", style = MaterialTheme.typography.titleMedium)
+                    }
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun ContactSearchField(query: String, active: Boolean, onToggle: () -> Unit) {
+    Surface(
+        onClick = onToggle,
+        shape = MaterialTheme.shapes.large,
+        color = if (active) MaterialTheme.colorScheme.primaryContainer else MaterialTheme.colorScheme.surfaceContainerHigh,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Text(
+            query.ifEmpty { "Search contacts" },
+            style = MaterialTheme.typography.bodyLarge,
+            color = if (query.isEmpty()) MaterialTheme.colorScheme.onSurfaceVariant else MaterialTheme.colorScheme.onSurface,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 14.dp),
+        )
+    }
+}
+
+@Composable
+private fun ContactRow(contact: Contact, onClick: () -> Unit) {
+    Surface(
+        onClick = onClick,
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(
+            Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 12.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            Box(
+                Modifier.size(40.dp).background(MaterialTheme.colorScheme.primaryContainer, CircleShape),
+                contentAlignment = Alignment.Center,
+            ) {
+                Text(
+                    contact.name.take(1).uppercase(),
+                    style = MaterialTheme.typography.titleMedium,
+                    color = MaterialTheme.colorScheme.onPrimaryContainer,
+                    fontWeight = FontWeight.Bold,
+                )
+            }
+            Column(Modifier.weight(1f)) {
+                Text(contact.name, style = MaterialTheme.typography.titleMedium, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                Text(contact.number, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+            }
+            Icon(Icons.Filled.Call, contentDescription = "Call", tint = MaterialTheme.colorScheme.primary)
+        }
+    }
+}

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

@@ -1,6 +1,9 @@
 package app.seb3thehacker.gearslip.car
 
 import android.graphics.Rect
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -13,6 +16,12 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.KeyboardArrowUp
+import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
@@ -21,20 +30,29 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.collectAsState
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.draw.rotate
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import androidx.car.app.model.CarIcon
 import androidx.car.app.model.Template
 import androidx.car.app.model.PlaceListMapTemplate
+import androidx.car.app.navigation.model.Lane
+import androidx.car.app.navigation.model.LaneDirection
 import androidx.car.app.navigation.model.MapTemplate
 import androidx.car.app.navigation.model.MapWithContentTemplate
 import androidx.car.app.navigation.model.NavigationTemplate
 import androidx.car.app.navigation.model.PlaceListNavigationTemplate
 import androidx.car.app.navigation.model.RoutePreviewNavigationTemplate
 import androidx.car.app.navigation.model.RoutingInfo
+import androidx.car.app.navigation.model.Step
 import androidx.car.app.navigation.model.TravelEstimate
+import app.seb3thehacker.gearslip.host.clockTime
 import app.seb3thehacker.gearslip.host.color
+import app.seb3thehacker.gearslip.host.image
 import app.seb3thehacker.gearslip.host.display
 import app.seb3thehacker.gearslip.host.remainingTime
 import app.seb3thehacker.gearslip.host.text
@@ -96,7 +114,7 @@ private fun NavigationChrome(template: NavigationTemplate, modifier: Modifier) {
             Modifier.align(Alignment.TopEnd).padding(12.dp),
         )
         if (!pan) template.destinationTravelEstimate?.let {
-            TravelEstimateBar(it, Modifier.align(Alignment.BottomStart))
+            TravelEstimateBar(it, Modifier.align(Alignment.BottomStart).padding(12.dp))
         }
     }
 }
@@ -106,7 +124,7 @@ private fun NavigationChrome(template: NavigationTemplate, modifier: Modifier) {
 private fun RoutingCard(info: RoutingInfo, modifier: Modifier = Modifier) {
     if (info.isLoading) {
         ChromeSurface(modifier) {
-            Text("Finding a route…", Modifier.padding(16.dp), style = MaterialTheme.typography.titleMedium)
+            Text("Finding a route…", Modifier.padding(16.dp), style = ChromeType.title)
         }
         return
     }
@@ -120,89 +138,174 @@ private fun RoutingCard(info: RoutingInfo, modifier: Modifier = Modifier) {
                 Column(Modifier.weight(1f)) {
                     val distance = info.currentDistance.display()
                     if (distance.isNotEmpty()) {
-                        Text(
-                            distance,
-                            style = MaterialTheme.typography.headlineSmall,
-                            fontWeight = FontWeight.Bold,
-                        )
+                        Text(distance, style = ChromeType.headline)
                     }
-                    Text(
-                        step.cue.text(),
-                        style = MaterialTheme.typography.titleMedium,
-                        maxLines = 2,
-                        overflow = TextOverflow.Ellipsis,
-                    )
+                    Text(step.cue.text(), style = ChromeType.title, maxLines = 2, overflow = TextOverflow.Ellipsis)
                 }
             }
             val road = step.road.text()
             if (road.isNotEmpty()) {
                 Text(
                     road,
-                    style = MaterialTheme.typography.bodyMedium,
+                    style = ChromeType.body,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
                 )
             }
+            // Neither is sent by every app - most say only "turn left" and trust the driver to
+            // find the lane themselves - so both are drawn only when there is something to draw.
+            info.junctionImage?.let { junction ->
+                Spacer(Modifier.height(10.dp))
+                JunctionImage(junction)
+            }
+            LaneGuidance(step, Modifier.padding(top = 10.dp))
             info.nextStep?.let { next ->
                 Spacer(Modifier.height(8.dp))
                 Row(verticalAlignment = Alignment.CenterVertically) {
-                    Text(
-                        "then",
-                        style = MaterialTheme.typography.labelMedium,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    )
+                    Text("then", style = ChromeType.label, color = MaterialTheme.colorScheme.onSurfaceVariant)
                     Spacer(Modifier.width(8.dp))
                     CarGlyph(next.maneuver?.icon, Modifier.size(20.dp))
                     Spacer(Modifier.width(8.dp))
-                    Text(
-                        next.cue.text(),
-                        style = MaterialTheme.typography.bodyMedium,
-                        maxLines = 1,
-                        overflow = TextOverflow.Ellipsis,
-                    )
+                    Text(next.cue.text(), style = ChromeType.body, maxLines = 1, overflow = TextOverflow.Ellipsis)
                 }
             }
         }
     }
 }
 
-/** Time and distance left, along the bottom where it stays out of the map's way. */
+/** The zoomed-in intersection an app draws for a junction too complex for an arrow to explain. */
+@Composable
+private fun JunctionImage(icon: CarIcon, modifier: Modifier = Modifier) {
+    val bitmap = icon.image(LocalContext.current) ?: return
+    Image(
+        bitmap,
+        contentDescription = null,
+        contentScale = ContentScale.Fit,
+        modifier = modifier.fillMaxWidth().heightIn(max = 120.dp),
+    )
+}
+
+/**
+ * Which lane to be in before the manoeuvre, either as the app's own picture ([Step.getLanesImage])
+ * or as a row of arrows built from its structured lane data - whichever it sent. The recommended
+ * lane, or lanes, stand out in the theme's own colour; the rest sit on the same muted, solid tile
+ * everything else uses, never dimmed by transparency.
+ */
+@Composable
+private fun LaneGuidance(step: Step, modifier: Modifier = Modifier) {
+    step.lanesImage?.let {
+        JunctionImage(it, modifier)
+        return
+    }
+    val lanes = step.lanes.orEmpty()
+    if (lanes.isEmpty()) return
+    Row(modifier, horizontalArrangement = Arrangement.spacedBy(6.dp)) {
+        lanes.forEach { lane -> LaneTile(lane) }
+    }
+}
+
+@Composable
+private fun LaneTile(lane: Lane) {
+    val directions = lane.directions.orEmpty()
+    val shown = directions.firstOrNull { it.isRecommended } ?: directions.firstOrNull()
+    val recommended = shown?.isRecommended == true
+    Box(
+        Modifier
+            .size(36.dp)
+            .clip(RoundedCornerShape(8.dp))
+            .background(
+                if (recommended) MaterialTheme.colorScheme.primaryContainer
+                else MaterialTheme.colorScheme.surfaceContainerHighest,
+            ),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            Icons.Filled.KeyboardArrowUp,
+            contentDescription = if (recommended) "Recommended lane" else "Lane",
+            tint = if (recommended) MaterialTheme.colorScheme.onPrimaryContainer
+            else MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(24.dp).rotate(shown.turnDegrees()),
+        )
+    }
+}
+
+/** The one arrow glyph this app draws, turned to stand in for every shape a lane can permit. */
+private fun LaneDirection?.turnDegrees(): Float = when (this?.shape) {
+    LaneDirection.SHAPE_SLIGHT_RIGHT -> 30f
+    LaneDirection.SHAPE_NORMAL_RIGHT -> 90f
+    LaneDirection.SHAPE_SHARP_RIGHT -> 135f
+    LaneDirection.SHAPE_U_TURN_RIGHT -> 170f
+    LaneDirection.SHAPE_SLIGHT_LEFT -> -30f
+    LaneDirection.SHAPE_NORMAL_LEFT -> -90f
+    LaneDirection.SHAPE_SHARP_LEFT -> -135f
+    LaneDirection.SHAPE_U_TURN_LEFT -> -170f
+    else -> 0f
+}
+
+/**
+ * The trip at a glance: time and distance left, the clock time it ends at, and - beside them,
+ * where a thumb reaches - the app's own way to stop navigating. A floating card rather than a
+ * full-width bar, so it reads as one thing beside the manoeuvre card above it instead of a strip
+ * that happens to hold three numbers. The close button is Gearslip's own, not the app's: an
+ * actionStrip's actions carry no flag saying which one (if any) means "stop navigating" - the
+ * first button here turned out to be a mute toggle, not an exit - so this leaves the app the way
+ * going Home already does, rather than guess at the app's own controls and risk getting it wrong.
+ */
 @Composable
 private fun TravelEstimateBar(estimate: TravelEstimate, modifier: Modifier = Modifier) {
-    val dark = MaterialTheme.colorScheme.surface.luminanceIsDark()
     val time = remainingTime(estimate.remainingTimeSeconds)
     val distance = estimate.remainingDistance.display()
+    val arrival = estimate.arrivalTimeAtDestination.clockTime()
     val trip = estimate.tripText.text()
-    if (time.isEmpty() && distance.isEmpty() && trip.isEmpty()) return
+    if (time.isEmpty() && distance.isEmpty() && arrival.isEmpty() && trip.isEmpty()) return
 
-    Surface(
-        color = Color.Black.copy(alpha = 0.6f),
-        contentColor = Color.White,
-        modifier = modifier.fillMaxWidth(),
-    ) {
+    val detail = listOfNotNull(
+        arrival.takeIf { it.isNotEmpty() },
+        distance.takeIf { it.isNotEmpty() },
+        trip.takeIf { it.isNotEmpty() },
+    ).joinToString("  •  ")
+
+    // The same solid card the manoeuvre card above it uses - one surface for the whole map
+    // chrome, rather than this one spot styled on its own as a bar over the map.
+    ChromeSurface(modifier, shadowElevation = 8.dp) {
+        val dark = MaterialTheme.colorScheme.surface.luminanceIsDark()
         Row(
-            Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
+            Modifier.padding(start = 8.dp, end = 18.dp, top = 10.dp, bottom = 10.dp),
             verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(20.dp),
         ) {
-            if (time.isNotEmpty()) {
-                Text(
-                    time,
-                    style = MaterialTheme.typography.titleLarge,
-                    fontWeight = FontWeight.Bold,
-                    color = estimate.remainingTimeColor.color(dark, Color.White),
+            Box(
+                Modifier
+                    .size(40.dp)
+                    .clip(CircleShape)
+                    .background(MaterialTheme.colorScheme.surfaceContainerHighest)
+                    // Not a disconnect: the connection stays up and the app decides its own next
+                    // screen. Ending navigation is its own call, separate from a back press - a
+                    // back press only pops the on-screen card, leaving the app still believing it
+                    // is navigating (so a freshly picked destination silently does nothing); this
+                    // is the call that actually clears that flag on the app's side.
+                    .clickable { CarServices.nav.stopNavigating() },
+                contentAlignment = Alignment.Center,
+            ) {
+                Icon(
+                    Icons.Filled.Close,
+                    contentDescription = "Stop navigating",
+                    tint = MaterialTheme.colorScheme.onSurface,
+                    modifier = Modifier.size(20.dp),
                 )
             }
-            if (distance.isNotEmpty()) {
-                Text(
-                    distance,
-                    style = MaterialTheme.typography.titleMedium,
-                    color = estimate.remainingDistanceColor.color(dark, Color.White),
-                )
-            }
-            if (trip.isNotEmpty()) {
-                Text(trip, style = MaterialTheme.typography.bodyMedium, maxLines = 1)
+            Spacer(Modifier.width(10.dp))
+            Column {
+                if (time.isNotEmpty()) {
+                    Text(
+                        time,
+                        style = ChromeType.headline,
+                        color = estimate.remainingTimeColor.color(dark, MaterialTheme.colorScheme.onSurface),
+                    )
+                }
+                if (detail.isNotEmpty()) {
+                    Text(detail, style = ChromeType.body, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                }
             }
         }
     }
@@ -258,7 +361,10 @@ private fun MapWithContentChrome(template: MapWithContentTemplate, modifier: Mod
         template.mapController?.mapActionStrip,
         fullHeight = template.contentTemplate.needsFullHeight(),
     ) {
-        ContentTemplate(template.contentTemplate, Modifier)
+        // A pane floating over the map is a place or a route the app is proposing, so its one
+        // action - Start - counts itself down rather than waiting to be pressed; the same pane
+        // filling a whole screen elsewhere gets no such push.
+        ContentTemplate(template.contentTemplate, Modifier, autoStartPane = true)
     }
 }
 
@@ -276,7 +382,7 @@ private fun MapChrome(template: MapTemplate, modifier: Modifier) {
                     template.header?.startHeaderAction,
                     template.header?.endHeaderActions.orEmpty(),
                 )
-                if (template.pane != null) PaneRows(template.pane)
+                if (template.pane != null) PaneRows(template.pane, autoStart = true)
                 else ItemListColumn(template.itemList)
             }
         }
@@ -322,13 +428,13 @@ private fun RoutePreviewChrome(template: RoutePreviewNavigationTemplate, modifie
                 )
                 Box(Modifier.weight(1f, fill = false)) {
                     if (template.isLoading) {
-                        Text("Finding routes…", Modifier.padding(14.dp))
+                        Text("Finding routes…", Modifier.padding(14.dp), style = ChromeType.title)
                     } else {
                         ItemListColumn(template.itemList)
                     }
                 }
                 template.navigateAction?.let {
-                    ActionRow(listOf(it), Modifier.padding(12.dp))
+                    AutoStartButton(it, Modifier.padding(12.dp))
                 }
             }
         }
@@ -346,7 +452,7 @@ private fun ListPane(
     ChromeSurface(modifier, shape = androidx.compose.foundation.shape.RoundedCornerShape(0.dp)) {
         Column {
             HeaderBar(title, startAction)
-            if (loading) Text("Loading…", Modifier.padding(14.dp))
+            if (loading) Text("Loading…", Modifier.padding(14.dp), style = ChromeType.title)
             else ItemListColumn(itemList)
         }
     }

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

@@ -27,6 +27,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.car.app.model.GridTemplate
@@ -51,6 +52,7 @@ import androidx.car.app.media.model.MediaPlaybackTemplate
 import androidx.car.app.OnDoneCallback
 import androidx.car.app.serialization.Bundleable
 import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.host.isDrawable
 import app.seb3thehacker.gearslip.host.inputChanged
 import app.seb3thehacker.gearslip.host.inputSubmitted
 import app.seb3thehacker.gearslip.host.submitted
@@ -65,12 +67,12 @@ import app.seb3thehacker.gearslip.host.textChanged
  * the same function either way - the only difference is how much room they get.
  */
 @Composable
-fun ContentTemplate(template: Template?, modifier: Modifier = Modifier) {
+fun ContentTemplate(template: Template?, modifier: Modifier = Modifier, autoStartPane: Boolean = false) {
     when (template) {
         null -> Unit
         is ListTemplate -> ListContent(template, modifier)
         is GridTemplate -> GridContent(template, modifier)
-        is PaneTemplate -> PaneContent(template, modifier)
+        is PaneTemplate -> PaneContent(template, modifier, autoStartPane)
         is MessageTemplate -> MessageContent(template, modifier)
         is LongMessageTemplate -> LongMessageContent(template, modifier)
         is SearchTemplate -> SearchContent(template, modifier)
@@ -126,7 +128,7 @@ private fun GridContent(template: GridTemplate, modifier: Modifier) {
 }
 
 @Composable
-private fun PaneContent(template: PaneTemplate, modifier: Modifier) {
+private fun PaneContent(template: PaneTemplate, modifier: Modifier, autoStart: Boolean = false) {
     ContentSurface(modifier) {
         HeaderBar(
             headerTitle(template.header, template.title.text()),
@@ -134,7 +136,7 @@ private fun PaneContent(template: PaneTemplate, modifier: Modifier) {
             template.header?.endHeaderActions.orEmpty(),
             template.actionStrip,
         )
-        if (template.pane?.isLoading == true) Loading() else PaneRows(template.pane)
+        if (template.pane?.isLoading == true) Loading() else PaneRows(template.pane, autoStart = autoStart)
     }
 }
 
@@ -143,27 +145,45 @@ private fun PaneContent(template: PaneTemplate, modifier: Modifier) {
 @Composable
 private fun MessageContent(template: MessageTemplate, modifier: Modifier) {
     ContentSurface(modifier) {
-        HeaderBar(
-            headerTitle(template.header, template.title.text()),
-            template.header?.startHeaderAction ?: template.headerAction,
-            template.header?.endHeaderActions.orEmpty(),
-            template.actionStrip,
-        )
+        // The header carries only the back arrow, not a title - a message template's own title
+        // is usually the long-form question ("Would you like to download the map...") that
+        // reads fine centred in the body but doesn't fit a one-line header without truncating.
+        val backAction = template.header?.startHeaderAction ?: template.headerAction
+        HeaderBar("", backAction, template.header?.endHeaderActions.orEmpty(), template.actionStrip)
         if (template.isLoading) {
             Loading()
             return@ContentSurface
         }
-        Row(
-            Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
-            verticalAlignment = Alignment.CenterVertically,
+        // A back arrow already undoes this screen, so an app's own "Cancel" button would just
+        // be a second way to do the one thing the header already offers.
+        val actions = template.actions.orEmpty().filter { it.isDrawable() }.let { list ->
+            if (backAction != null) list.filterNot { it.title.text().equals("Cancel", ignoreCase = true) } else list
+        }
+        Column(
+            Modifier.weight(1f).fillMaxWidth().padding(24.dp),
+            verticalArrangement = Arrangement.Center,
+            horizontalAlignment = Alignment.CenterHorizontally,
         ) {
             template.icon?.let {
-                CarGlyph(it, Modifier.size(32.dp))
-                Spacer(Modifier.width(12.dp))
+                CarGlyph(it, Modifier.size(40.dp))
+                Spacer(Modifier.height(12.dp))
+            }
+            Text(template.title.text(), style = ChromeType.title, textAlign = TextAlign.Center)
+            val detail = template.message.text()
+            if (detail.isNotEmpty()) {
+                Spacer(Modifier.height(8.dp))
+                Text(
+                    detail,
+                    style = ChromeType.body,
+                    textAlign = TextAlign.Center,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+            if (actions.isNotEmpty()) {
+                Spacer(Modifier.height(24.dp))
+                ActionRow(actions, Modifier.fillMaxWidth(0.6f), large = true)
             }
-            Text(template.message.text(), style = MaterialTheme.typography.bodyLarge)
         }
-        ActionRow(template.actions.orEmpty(), Modifier.padding(16.dp))
     }
 }
 
@@ -181,7 +201,7 @@ private fun LongMessageContent(template: LongMessageTemplate, modifier: Modifier
         )
         Text(
             template.message.text(),
-            style = MaterialTheme.typography.bodyMedium,
+            style = ChromeType.body,
             modifier = Modifier
                 .weight(1f)
                 .verticalScroll(rememberScrollState())
@@ -245,7 +265,7 @@ private fun SearchField(query: String, hint: String, modifier: Modifier = Modifi
     ) {
         Text(
             query.ifEmpty { hint.ifEmpty { "Search" } },
-            style = MaterialTheme.typography.titleMedium,
+            style = ChromeType.body,
             color = if (query.isEmpty()) MaterialTheme.colorScheme.onSurfaceVariant
             else MaterialTheme.colorScheme.onSurface,
             maxLines = 1,
@@ -279,7 +299,7 @@ private fun SignInContent(template: SignInTemplate, modifier: Modifier) {
         if (instructions.isNotEmpty()) {
             Text(
                 instructions,
-                style = MaterialTheme.typography.bodyLarge,
+                style = ChromeType.body,
                 modifier = Modifier.padding(horizontal = 16.dp, vertical = 6.dp),
             )
         }
@@ -298,7 +318,7 @@ private fun SignInContent(template: SignInTemplate, modifier: Modifier) {
         if (additional.isNotEmpty()) {
             Text(
                 additional,
-                style = MaterialTheme.typography.bodySmall,
+                style = ChromeType.label,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
                 modifier = Modifier.padding(horizontal = 16.dp),
             )
@@ -319,7 +339,7 @@ private fun InputSignIn(method: InputSignInMethod, modifier: Modifier) {
         if (error.isNotEmpty()) {
             Text(
                 error,
-                style = MaterialTheme.typography.bodySmall,
+                style = ChromeType.label,
                 color = MaterialTheme.colorScheme.error,
                 modifier = Modifier.padding(horizontal = 16.dp),
             )
@@ -343,8 +363,7 @@ private fun Callout(value: String, modifier: Modifier) {
     Box(modifier.fillMaxWidth(), contentAlignment = Alignment.Center) {
         Text(
             value,
-            style = MaterialTheme.typography.headlineMedium,
-            fontWeight = FontWeight.Bold,
+            style = ChromeType.headline,
             textAlign = androidx.compose.ui.text.style.TextAlign.Center,
         )
     }
@@ -385,7 +404,7 @@ private fun TabContent(template: TabTemplate, modifier: Modifier) {
                             CarGlyph(it, Modifier.size(20.dp))
                             Spacer(Modifier.width(6.dp))
                         }
-                        Text(tab.title.text(), style = MaterialTheme.typography.labelLarge, maxLines = 1)
+                        Text(tab.title.text(), style = ChromeType.label, maxLines = 1)
                     }
                 }
             }
@@ -450,7 +469,7 @@ private fun SectionRows(section: Section<*>) {
 
     if (items.isEmpty()) {
         val message = section.noItemsMessage.text()
-        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp))
+        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp), style = ChromeType.body)
         return
     }
     items.filterIsInstance<CarRow>().forEach { RowItem(it) }
@@ -474,7 +493,7 @@ private fun MediaPlaybackContent(template: MediaPlaybackTemplate, modifier: Modi
         Box(Modifier.weight(1f).fillMaxWidth(), contentAlignment = Alignment.Center) {
             Text(
                 "Playback controls come from the app's media session,\nwhich Gearslip doesn't carry yet.",
-                style = MaterialTheme.typography.bodyMedium,
+                style = ChromeType.body,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
                 textAlign = androidx.compose.ui.text.style.TextAlign.Center,
             )
@@ -496,6 +515,6 @@ private typealias ColumnScopeAlias = androidx.compose.foundation.layout.ColumnSc
 @Composable
 private fun Loading() {
     Box(Modifier.fillMaxWidth().height(80.dp), contentAlignment = Alignment.Center) {
-        Text("Loading…", style = MaterialTheme.typography.bodyLarge)
+        Text("Loading…", style = ChromeType.title)
     }
 }

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

@@ -4,12 +4,14 @@ import androidx.compose.runtime.remember
 import androidx.compose.material3.LocalContentColor
 import androidx.compose.ui.graphics.ColorFilter
 import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
@@ -82,19 +84,21 @@ import app.seb3thehacker.gearslip.host.text
 /**
  * The app keeps drawing its map across the whole surface - the visible area we report tells it
  * where to put its own markers, not where to stop painting. So anything the host lays over the
- * map is opaque by default, or the map reads through it.
+ * map is opaque, always, in the same one colour: a card that lets the map show through in places
+ * reads as broken glass, not as a deliberate choice, and a driver has no way to tell which was
+ * meant. There is no alpha knob here on purpose - every card, bar and strip in the template
+ * chrome shares this surface, so nothing drawn over a map is ever see-through.
  */
 @Composable
 internal fun ChromeSurface(
     modifier: Modifier = Modifier,
     shape: Shape = RoundedCornerShape(16.dp),
-    alpha: Float = 1f,
     shadowElevation: androidx.compose.ui.unit.Dp = 0.dp,
     content: @Composable () -> Unit,
 ) {
     Surface(
         shadowElevation = shadowElevation,
-        color = MaterialTheme.colorScheme.surface.copy(alpha = alpha),
+        color = MaterialTheme.colorScheme.surface,
         contentColor = MaterialTheme.colorScheme.onSurface,
         shape = shape,
         modifier = modifier,
@@ -102,6 +106,32 @@ internal fun ChromeSurface(
     )
 }
 
+/**
+ * The one type scale for everything a templated app's screen draws. Apps hand the host plain
+ * strings with no size of their own - the Car App Library deliberately keeps that decision out of
+ * their hands - so without a shared scale, each template's text ends up whatever size felt right
+ * when that template was written, and two apps' otherwise-identical rows read as different sizes
+ * of importance. Every car chrome file should reach for one of these four rather than naming a
+ * Material size directly.
+ */
+internal object ChromeType {
+    /** The one number or word a card exists to show: distance to a turn, minutes left, a PIN. */
+    val headline: androidx.compose.ui.text.TextStyle
+        @Composable get() = MaterialTheme.typography.headlineMedium.copy(fontWeight = FontWeight.Bold)
+
+    /** A row's name, a header, a manoeuvre's instruction - the line the rest is supporting. */
+    val title: androidx.compose.ui.text.TextStyle
+        @Composable get() = MaterialTheme.typography.titleLarge.copy(fontWeight = FontWeight.SemiBold)
+
+    /** Supporting detail: a road, an address, a message's body, a second line under a title. */
+    val body: androidx.compose.ui.text.TextStyle
+        @Composable get() = MaterialTheme.typography.titleMedium
+
+    /** The smallest text Gearslip draws over a map - still large enough to read while moving. */
+    val label: androidx.compose.ui.text.TextStyle
+        @Composable get() = MaterialTheme.typography.bodyLarge
+}
+
 @Composable
 internal fun UnsupportedChrome(template: Template, modifier: Modifier = Modifier) {
     androidx.compose.foundation.layout.Box(modifier, contentAlignment = Alignment.Center) {
@@ -109,7 +139,7 @@ internal fun UnsupportedChrome(template: Template, modifier: Modifier = Modifier
             Text(
                 "${template.javaClass.simpleName} isn't drawn yet",
                 Modifier.padding(16.dp),
-                style = MaterialTheme.typography.titleMedium,
+                style = ChromeType.title,
             )
         }
     }
@@ -142,8 +172,7 @@ internal fun HeaderBar(
         startAction?.takeIf { it.isDrawable() }?.let { ActionButton(it) }
         Text(
             title,
-            style = MaterialTheme.typography.titleLarge,
-            fontWeight = FontWeight.SemiBold,
+            style = ChromeType.title,
             color = MaterialTheme.colorScheme.onSurface,
             maxLines = 1,
             overflow = TextOverflow.Ellipsis,
@@ -285,12 +314,7 @@ internal fun ActionButton(action: Action, large: Boolean = false, modifier: Modi
                 contentAlignment = Alignment.Center,
             ) {
                 if (hasGlyph) CarGlyph(action.icon, Modifier.size(30.dp).align(Alignment.CenterStart), standardFor(action))
-                Text(
-                    title,
-                    style = MaterialTheme.typography.titleLarge,
-                    fontWeight = FontWeight.SemiBold,
-                    maxLines = 1,
-                )
+                Text(title, style = ChromeType.title, maxLines = 1)
             }
         } else if (title.isEmpty()) {
             // Every icon-only button - back, settings, the map's zoom and locate - is the same size.
@@ -304,12 +328,82 @@ internal fun ActionButton(action: Action, large: Boolean = false, modifier: Modi
             ) {
                 if (hasGlyph) CarGlyph(action.icon, Modifier.size(24.dp), standardFor(action))
                 if (hasGlyph) Spacer(Modifier.width(8.dp))
-                Text(title, style = MaterialTheme.typography.titleMedium, maxLines = 1)
+                Text(title, style = ChromeType.body, maxLines = 1)
             }
         }
     }
 }
 
+/**
+ * A large action that fires on its own after five seconds, filling to show the countdown - for
+ * the one button on a map-preview pane, where the app is proposing a single place or route and a
+ * driver glancing at the car screen has already decided. Tapping it, same as any other button,
+ * fires it at once; the fill is only ever a preview of what a touch already does.
+ */
+@Composable
+internal fun AutoStartButton(action: Action, modifier: Modifier = Modifier) {
+    var fraction by remember(action.identity()) { mutableStateOf(0f) }
+    var fired by remember(action.identity()) { mutableStateOf(false) }
+    fun fire() {
+        if (fired) return
+        fired = true
+        action.onClickDelegate.click("auto-start")
+    }
+    androidx.compose.runtime.LaunchedEffect(action.identity()) {
+        val steps = 60
+        repeat(steps) { step ->
+            kotlinx.coroutines.delay(AUTO_START_MS / steps)
+            fraction = (step + 1) / steps.toFloat()
+        }
+        fire()
+    }
+
+    val dark = MaterialTheme.colorScheme.surface.luminanceIsDark()
+    val custom = action.backgroundColor?.type?.let { it != androidx.car.app.model.CarColor.TYPE_DEFAULT } == true
+    val background = action.backgroundColor.color(dark, MaterialTheme.colorScheme.primary)
+    val content = if (custom) Color.White else MaterialTheme.colorScheme.onPrimary
+    val hasGlyph = action.icon != null
+
+    Surface(
+        // An unfilled track, solid, not the button's own colour dimmed with alpha - so the map
+        // behind never shows through however much of the five seconds is left.
+        color = MaterialTheme.colorScheme.surfaceContainerHighest,
+        contentColor = content,
+        shape = RoundedCornerShape(28.dp),
+        modifier = modifier.fillMaxWidth().clickable(enabled = action.isEnabled) { fire() },
+    ) {
+        androidx.compose.foundation.layout.Box {
+            // The countdown itself: a plain fill sweeping left to right underneath the label.
+            // matchParentSize(), not fillMaxHeight() - this Box sits beside a label Box that
+            // wraps its own content, and the outer Box sizes itself to its tallest child; a
+            // plain fillMaxHeight() here has nothing bounded to fill up to but the whole screen,
+            // which is what was stretching the whole button that tall. matchParentSize() instead
+            // takes whatever size the label ends up being, without itself voting on what that is.
+            androidx.compose.foundation.layout.Box(Modifier.matchParentSize()) {
+                androidx.compose.foundation.layout.Box(
+                    Modifier
+                        .fillMaxWidth(fraction)
+                        .fillMaxHeight()
+                        .background(background),
+                )
+            }
+            androidx.compose.foundation.layout.Box(
+                Modifier.fillMaxWidth().padding(horizontal = 20.dp, vertical = 16.dp),
+                contentAlignment = Alignment.Center,
+            ) {
+                if (hasGlyph) CarGlyph(action.icon, Modifier.size(24.dp).align(Alignment.CenterStart))
+                Text(
+                    action.title.text().ifEmpty { "Start" },
+                    style = ChromeType.title,
+                    maxLines = 1,
+                )
+            }
+        }
+    }
+}
+
+private const val AUTO_START_MS = 5_000L
+
 /** The connected app's own launcher icon, which is what the app-icon action stands for. */
 @Composable
 private fun AppIconBadge() {
@@ -376,8 +470,7 @@ internal fun PaneTitle(title: String) {
     if (title.isEmpty()) return
     Text(
         title,
-        style = MaterialTheme.typography.titleMedium,
-        fontWeight = FontWeight.SemiBold,
+        style = ChromeType.title,
         modifier = Modifier.padding(horizontal = 14.dp, vertical = 10.dp),
     )
 }
@@ -394,7 +487,7 @@ internal fun ItemListColumn(
     }
     if (rows.isEmpty()) {
         val message = single?.noItemsMessage.text()
-        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp))
+        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp), style = ChromeType.body)
         return
     }
     // A list the app made selectable is a single-choice list: one option chosen, shown as a radio.
@@ -430,7 +523,7 @@ internal fun GridItems(list: ItemList?, modifier: Modifier = Modifier) {
                 Spacer(Modifier.height(6.dp))
                 Text(
                     item.title.text(),
-                    style = MaterialTheme.typography.labelLarge,
+                    style = ChromeType.label,
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
                 )
@@ -438,7 +531,7 @@ internal fun GridItems(list: ItemList?, modifier: Modifier = Modifier) {
                 if (subtitle.isNotEmpty()) {
                     Text(
                         subtitle,
-                        style = MaterialTheme.typography.labelSmall,
+                        style = ChromeType.label,
                         color = MaterialTheme.colorScheme.onSurfaceVariant,
                         maxLines = 1,
                         overflow = TextOverflow.Ellipsis,
@@ -449,17 +542,24 @@ internal fun GridItems(list: ItemList?, modifier: Modifier = Modifier) {
     }
 }
 
+/**
+ * [autoStart] is for a pane floating over a map - a place or a route the app is proposing - where
+ * a single action counts itself down rather than waiting to be pressed, on the theory that a
+ * driver glancing at the car screen has already decided. It never applies to more than one
+ * action: a pane offering a real choice (Start vs. something else) always waits to be tapped.
+ */
 @Composable
-internal fun PaneRows(pane: Pane?, modifier: Modifier = Modifier) {
+internal fun PaneRows(pane: Pane?, modifier: Modifier = Modifier, autoStart: Boolean = false) {
     // Some apps pad a pane with a row of blank strings; drawn, it is just a gap.
     val rows = pane?.rows.orEmpty().filterNot { it.isBlank() }
+    val actions = pane?.actions.orEmpty().filter { it.isDrawable() }
     Column(modifier) {
         rows.forEach { RowItem(it, large = true) }
-        ActionRow(
-            pane?.actions.orEmpty(),
-            Modifier.padding(horizontal = 14.dp, vertical = 10.dp),
-            large = true,
-        )
+        if (autoStart && actions.size == 1) {
+            AutoStartButton(actions.single(), Modifier.padding(horizontal = 14.dp, vertical = 10.dp))
+        } else {
+            ActionRow(actions, Modifier.padding(horizontal = 14.dp, vertical = 10.dp), large = true)
+        }
     }
 }
 
@@ -496,18 +596,20 @@ internal fun RowItem(row: CarRow, selection: RowSelection? = null, large: Boolea
             CarGlyph(it, Modifier.size(28.dp))
             Spacer(Modifier.width(12.dp))
         }
+        // large only changes how much room a row gets (more lines, a bigger icon above) - the
+        // type itself is the same scale as every other row, so a pane's one row and a plain
+        // list's tenth row read as the same kind of text.
         Column(Modifier.weight(1f)) {
             Text(
                 row.title.text(),
-                style = if (large) MaterialTheme.typography.headlineSmall else MaterialTheme.typography.bodyLarge,
-                fontWeight = if (large) FontWeight.SemiBold else null,
+                style = ChromeType.title,
                 maxLines = if (large) 2 else 1,
                 overflow = TextOverflow.Ellipsis,
             )
             row.texts.orEmpty().take(if (large) 3 else 2).forEach { line ->
                 Text(
                     line.text(),
-                    style = if (large) MaterialTheme.typography.titleMedium else MaterialTheme.typography.bodyMedium,
+                    style = ChromeType.body,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                     maxLines = if (large) 2 else 1,
                     overflow = TextOverflow.Ellipsis,

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

@@ -1,10 +1,14 @@
 package app.seb3thehacker.gearslip.car
 
+import android.os.Handler
+import android.os.Looper
+import android.webkit.JavascriptInterface
 import android.webkit.WebResourceError
 import android.webkit.WebResourceRequest
 import android.webkit.WebResourceResponse
 import android.webkit.WebView
 import android.webkit.WebViewClient
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
@@ -15,16 +19,25 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.viewinterop.AndroidView
 import app.seb3thehacker.gearslip.GearslipLog
+import org.json.JSONObject
 
 /**
  * A browser inside the car UI. [content] is a URL, or raw HTML when it does not look like one.
  * The bottom bar's Back walks the page history first and only leaves the app at the start.
+ *
+ * A page's own text inputs can't call up the phone's IME: the car UI lives in a Presentation on
+ * a virtual display, and the platform's soft keyboard has nowhere sensible to appear there (see
+ * [CarKeyboard]'s doc comment - every other text field in this app already draws its own for the
+ * same reason). [FOCUS_TRACKING_JS] reports focus/blur on the page's editable elements, and
+ * [CarKeyboard] edits the focused one back through injected JS instead of through the DOM's own
+ * native input path, which this Presentation can't reach.
  */
 @Composable
 fun WebApp(content: String) {
     val navigator = LocalCarNavigator.current
     val darkOutside = LocalDarkOutside.current
     var web by remember { mutableStateOf<WebView?>(null) }
+    var fieldText by remember { mutableStateOf<String?>(null) }
 
     DisposableEffect(web) {
         navigator.backInterceptor = {
@@ -39,32 +52,49 @@ fun WebApp(content: String) {
         onDispose { navigator.backInterceptor = null }
     }
 
-    AndroidView(
-        modifier = Modifier.fillMaxSize(),
-        factory = { context ->
-            WebView(context).apply {
-                settings.javaScriptEnabled = true
-                settings.domStorageEnabled = true
-                settings.loadWithOverviewMode = true
-                settings.useWideViewPort = true
-                webViewClient = LoggingClient()
-                if (content.startsWith("http://") || content.startsWith("https://")) {
-                    loadUrl(content)
-                } else {
-                    loadDataWithBaseURL(null, content, "text/html", "utf-8", null)
+    Column(Modifier.fillMaxSize()) {
+        AndroidView(
+            modifier = Modifier.weight(1f).fillMaxSize(),
+            factory = { context ->
+                WebView(context).apply {
+                    settings.javaScriptEnabled = true
+                    settings.domStorageEnabled = true
+                    settings.loadWithOverviewMode = true
+                    settings.useWideViewPort = true
+                    webViewClient = LoggingClient()
+                    addJavascriptInterface(
+                        FieldFocusBridge(onFocus = { fieldText = it }, onBlur = { fieldText = null }),
+                        "GearslipField",
+                    )
+                    if (content.startsWith("http://") || content.startsWith("https://")) {
+                        loadUrl(content)
+                    } else {
+                        loadDataWithBaseURL(null, content, "text/html", "utf-8", null)
+                    }
+                    web = this
                 }
-                web = this
-            }
-        },
-        // Pages that honour it follow the darkness outside; a first, tweakable use of the signal.
-        update = { it.settings.isAlgorithmicDarkeningAllowed = darkOutside },
-        onRelease = { it.destroy() },
-    )
+            },
+            // Pages that honour it follow the darkness outside; a first, tweakable use of the signal.
+            update = { it.settings.isAlgorithmicDarkeningAllowed = darkOutside },
+            onRelease = { it.destroy() },
+        )
+        fieldText?.let { text ->
+            CarKeyboard(
+                text = text,
+                onTextChange = { updated ->
+                    fieldText = updated
+                    web?.evaluateJavascript(setFieldValueJs(updated), null)
+                },
+                onSubmit = { web?.evaluateJavascript(SUBMIT_FIELD_JS, null) },
+            )
+        }
+    }
 }
 
 private class LoggingClient : WebViewClient() {
     override fun onPageFinished(view: WebView?, url: String?) {
         GearslipLog.i("car web page loaded: $url")
+        view?.evaluateJavascript(FOCUS_TRACKING_JS, null)
     }
 
     // onPageFinished fires for error pages too, so without this a blocked load (missing
@@ -81,3 +111,70 @@ private class LoggingClient : WebViewClient() {
         }
     }
 }
+
+/** Tells Kotlin when an editable element on the page gains or loses focus, so [CarKeyboard] can show. */
+private class FieldFocusBridge(private val onFocus: (String) -> Unit, private val onBlur: () -> Unit) {
+    private val main = Handler(Looper.getMainLooper())
+
+    // WebView calls into this from its own thread, never Compose's.
+    @JavascriptInterface
+    fun focused(value: String) { main.post { onFocus(value) } }
+
+    @JavascriptInterface
+    fun blurred() { main.post { onBlur() } }
+}
+
+// Plain `el.value = x` never reaches a React-controlled input: React replaces the native value
+// setter with its own to track edits, so a direct assignment sets the DOM attribute but leaves
+// React's own state (and anything bound to it, like a search box's query) unaware. Calling the
+// *native* setter through the prototype, the same trick browser extensions use, is what actually
+// notifies it once the 'input' event fires.
+private fun setFieldValueJs(value: String) = """
+    (function() {
+        var el = document.activeElement;
+        if (!el) return;
+        var proto = el.tagName === 'TEXTAREA' ? window.HTMLTextAreaElement.prototype : window.HTMLInputElement.prototype;
+        var setter = Object.getOwnPropertyDescriptor(proto, 'value');
+        if (setter && setter.set) { setter.set.call(el, ${JSONObject.quote(value)}); } else { el.value = ${JSONObject.quote(value)}; }
+        el.dispatchEvent(new Event('input', { bubbles: true }));
+        el.dispatchEvent(new Event('change', { bubbles: true }));
+    })();
+""".trimIndent()
+
+// Fires a real Enter keydown first - the same event a site's own JS would see from a physical
+// keyboard - and only falls back to submitting the form directly if nothing handled it, so a
+// search-as-you-type page and a plain <form> both work without submitting twice.
+private const val SUBMIT_FIELD_JS = """
+    (function() {
+        var el = document.activeElement;
+        if (!el) return;
+        var enter = new KeyboardEvent('keydown', {
+            key: 'Enter', code: 'Enter', keyCode: 13, which: 13, bubbles: true, cancelable: true,
+        });
+        var notHandled = el.dispatchEvent(enter);
+        if (notHandled && el.form) {
+            if (el.form.requestSubmit) el.form.requestSubmit(); else el.form.submit();
+        }
+    })();
+"""
+
+/** Reports focus/blur on text inputs, textareas and contenteditable elements to [FieldFocusBridge]. */
+private const val FOCUS_TRACKING_JS = """
+    (function() {
+        function isEditable(el) {
+            if (!el) return false;
+            var tag = el.tagName;
+            if (tag === 'TEXTAREA') return true;
+            if (el.isContentEditable) return true;
+            if (tag !== 'INPUT') return false;
+            var skip = ['button', 'submit', 'checkbox', 'radio', 'range', 'color', 'file', 'image', 'reset'];
+            return skip.indexOf((el.type || 'text').toLowerCase()) === -1;
+        }
+        document.addEventListener('focusin', function(e) {
+            if (isEditable(e.target)) window.GearslipField.focused(e.target.value || '');
+        });
+        document.addEventListener('focusout', function(e) {
+            if (isEditable(e.target)) window.GearslipField.blurred();
+        });
+    })();
+"""

gearslip/src/main/java/app/seb3thehacker/gearslip/host/AndroidAuto.kt

@@ -1,11 +1,19 @@
 package app.seb3thehacker.gearslip.host
 
+import android.content.Context
+import android.content.pm.PackageManager
+
 /**
  * Google's own Android Auto, in whatever guise it appears. Gearslip replaces it, so its entries
  * (there are many: one per screen it registers) are noise in every list of apps to open.
  */
 object AndroidAuto {
 
+    /** Kept in sync with the `<queries><package>` entries in the manifest: package visibility
+     * hides an app's presence entirely unless one names it (or a broader query matches it), and
+     * this one has no launcher icon on current builds for a launcher-category query to find. */
+    private val KNOWN_PACKAGES = listOf("com.google.android.projection.gearhead")
+
     private val PACKAGE_MARKERS = listOf("gearhead", "projection.gearhead", "android.auto", "androidauto")
 
     fun matches(packageName: String, label: String): Boolean {
@@ -14,4 +22,26 @@ object AndroidAuto {
         val name = label.lowercase().replace(Regex("[^a-z ]"), " ")
         return "android auto" in name || "androidauto" in name.replace(" ", "")
     }
+
+    /** The package name of Google's Android Auto, if it is installed. */
+    fun installedPackage(context: Context): String? {
+        val manager = context.packageManager
+        return KNOWN_PACKAGES.firstOrNull { pkg ->
+            runCatching { manager.getPackageInfo(pkg, 0) }.isSuccess
+        }
+    }
+
+    /**
+     * Whether [packageName] can still fight Gearslip for the USB connection: installed, and not
+     * already disabled for this user. `ApplicationInfo.enabled` only reflects the manifest's
+     * static default, not a driver's own Settings toggle, so this reads the actual runtime
+     * setting instead - a driver who disabled it instead of uninstalling it (the app info screen
+     * offers both) has already done what this step asks.
+     */
+    fun isActive(context: Context, packageName: String): Boolean {
+        val setting = runCatching { context.packageManager.getApplicationEnabledSetting(packageName) }
+            .getOrDefault(PackageManager.COMPONENT_ENABLED_STATE_DEFAULT)
+        return setting == PackageManager.COMPONENT_ENABLED_STATE_DEFAULT ||
+            setting == PackageManager.COMPONENT_ENABLED_STATE_ENABLED
+    }
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/host/CarAppCatalog.kt

@@ -41,6 +41,7 @@ object CarAppCatalog {
             .asSequence()
             .filter { it.serviceInfo.packageName != context.packageName }
             .filterNot { AndroidAuto.matches(it.serviceInfo.packageName, it.loadLabel(manager).toString()) }
+            .filterNot { KnownApps.isHidden(it.serviceInfo.packageName) }
             .map { resolved ->
                 val info = resolved.serviceInfo
                 TemplateApp(

gearslip/src/main/java/app/seb3thehacker/gearslip/host/CarAppConnection.kt

@@ -31,6 +31,7 @@ import androidx.car.app.suggestion.ISuggestionHost
 import androidx.car.app.hardware.ICarHardwareHost
 import androidx.car.app.hardware.ICarHardwareResult
 import androidx.car.app.navigation.INavigationHost
+import androidx.car.app.navigation.INavigationManager
 import androidx.car.app.serialization.Bundleable
 import androidx.car.app.versioning.CarAppApiLevels
 import app.seb3thehacker.gearslip.GearslipLog
@@ -81,6 +82,8 @@ class CarAppConnection(private val context: Context) {
 
     private var carApp: ICarApp? = null
     private var appManager: IAppManager? = null
+    /** Only present for an app that asked for it - most apps aren't navigation apps. */
+    private var navigationManager: INavigationManager? = null
     /** Main thread only, both of these - the handoff is a race between them either way round. */
     private var surfaceCallback: ISurfaceCallback? = null
     private var lent: Lent? = null
@@ -189,6 +192,7 @@ class CarAppConnection(private val context: Context) {
         binding = null
         this.carApp = null
         appManager = null
+        navigationManager = null
         _panMode.value = false
         surfaceCallback = null
         component = null
@@ -269,6 +273,37 @@ class CarAppConnection(private val context: Context) {
             if (appManager == null) GearslipLog.e("host: app manager was ${value?.javaClass?.name}")
             requestTemplate()
         }) { app.getManager(CarContext.APP_SERVICE, it) }
+
+        // Best-effort and silent: an app that never asked for NavigationManager (not every
+        // templated app navigates) simply has no binder to hand back, which is normal, not a
+        // failure worth surfacing.
+        runCatching {
+            app.getManager(CarContext.NAVIGATION_SERVICE, object : IOnDoneCallback.Stub() {
+                override fun onSuccess(response: Bundleable?) {
+                    val value = response?.let { runCatching { it.get() }.getOrNull() }
+                    navigationManager = when (value) {
+                        is INavigationManager -> value
+                        is IBinder -> INavigationManager.Stub.asInterface(value)
+                        else -> null
+                    }
+                }
+                override fun onFailure(response: Bundleable?) = Unit
+            })
+        }
+    }
+
+    /**
+     * Tells the app itself to stop navigating - the proper end of a route, not just leaving its
+     * screen. Ending only the on-screen guidance (a back press) leaves the app's own
+     * "am I navigating" flag set, which is what stopped a fresh route from starting afterwards;
+     * this is the call [NavigationManagerCallback.onStopNavigation] on the app's side answers,
+     * and it is expected to clear that flag and present its own post-navigation screen.
+     */
+    fun stopNavigating() {
+        val manager = navigationManager ?: return
+        GearslipLog.i("host: asking the app to stop navigating")
+        runCatching { manager.onStopNavigation(noop("stop navigation")) }
+            .onFailure { GearslipLog.w("host: could not stop navigation: ${it.message}") }
     }
 
     /** The app describes its current screen; this is what the host draws. */

gearslip/src/main/java/app/seb3thehacker/gearslip/host/CarModels.kt

@@ -91,6 +91,17 @@ fun remainingTime(seconds: Long): String {
     return if (hours > 0) "$hours hr $minutes min" else "$minutes min"
 }
 
+/** "1:10 AM" - the clock at the destination, not the phone's own, in case a route crosses a zone. */
+fun androidx.car.app.model.DateTimeWithZone?.clockTime(): String {
+    val at = this ?: return ""
+    val shifted = java.util.Date(at.timeSinceEpochMillis + at.zoneOffsetSeconds * 1000L)
+    return runCatching {
+        java.text.SimpleDateFormat("h:mm a", java.util.Locale.getDefault()).apply {
+            timeZone = java.util.TimeZone.getTimeZone("UTC")
+        }.format(shifted)
+    }.getOrDefault("")
+}
+
 /**
  * Tells the app something was tapped.
  *

gearslip/src/main/java/app/seb3thehacker/gearslip/host/KnownApps.kt

@@ -14,7 +14,28 @@ object KnownApps {
         "app.organicmaps",       // Organic Maps: map, search, routing, settings
         "net.osmand.plus",       // OsmAnd: map, search, routing, settings
         "in.krosbits.musicolet", // Musicolet: browse, play, seek, lyrics
+        "com.kododake.aabrowser", // Aardvark: browser template, starts, draws, takes touches
+        "com.vivi.vivimusic", // Vivi Music: browse, play, seek, works well
     )
 
     fun works(packageName: String): Boolean = packageName in working
+
+    /**
+     * Registers a car template service but never gives Gearslip a usable screen - left off the
+     * launcher entirely rather than shown as a tile that goes nowhere.
+     */
+    private val hidden = setOf(
+        "com.google.android.dialer",               // Google Phone
+        "com.google.android.googlequicksearchbox",  // Google Assistant driving surfaces
+    )
+
+    fun isHidden(packageName: String): Boolean = packageName in hidden
+
+    /** Shown on the launcher with a red X: known broken, but expected enough that hiding it outright would look like a bug. */
+    private val broken = setOf(
+        "com.google.android.apps.messaging", // Google Messages
+        "com.waze",                          // Waze
+    )
+
+    fun isBroken(packageName: String): Boolean = packageName in broken
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/media/CarMedia.kt

@@ -6,6 +6,7 @@ import android.graphics.Bitmap
 import android.media.MediaMetadata
 import android.media.browse.MediaBrowser
 import android.media.session.MediaController
+import android.media.session.MediaSession
 import android.media.session.MediaSessionManager
 import android.media.session.PlaybackState
 import android.net.Uri
@@ -33,6 +34,15 @@ class MediaEntry(
 
 class CustomAction(val id: String, val name: String, val extras: Bundle?)
 
+/** One entry in the app's own queue - not its library, whatever it has lined up to play next. */
+class QueueTrack(
+    val queueId: Long,
+    val title: String,
+    val subtitle: String,
+    val iconUri: Uri?,
+    val iconBitmap: Bitmap?,
+)
+
 /** What is playing, as the car's now-playing panel needs it. */
 class NowPlaying(
     val title: String = "",
@@ -48,6 +58,8 @@ class NowPlaying(
     val actions: Long = 0,
     val custom: List<CustomAction> = emptyList(),
     val error: String? = null,
+    /** Which [QueueTrack.queueId] is playing now, so "up next" can show what follows it. */
+    val activeQueueItemId: Long = MediaSession.QueueItem.UNKNOWN_ID.toLong(),
 ) {
     val playing get() = state == PlaybackState.STATE_PLAYING || state == PlaybackState.STATE_BUFFERING
     val hasTrack get() = title.isNotEmpty() || state != PlaybackState.STATE_NONE
@@ -109,6 +121,9 @@ class CarMedia(private val context: Context) {
     private val _now = MutableStateFlow(NowPlaying())
     val now: StateFlow<NowPlaying> = _now.asStateFlow()
 
+    private val _queue = MutableStateFlow<List<QueueTrack>>(emptyList())
+    val queue: StateFlow<List<QueueTrack>> = _queue.asStateFlow()
+
     private var browser: MediaBrowser? = null
     private var controller: MediaController? = null
     private var subscribed: String? = null
@@ -171,6 +186,7 @@ class CarMedia(private val context: Context) {
         controller = session.also {
             it.registerCallback(callback)
             update(it.metadata, it.playbackState)
+            _queue.value = queueOf(it.queue)
         }
         _browse.value = BrowseState(loading = false, unavailable = true)
         _phase.value = Phase.READY
@@ -182,6 +198,7 @@ class CarMedia(private val context: Context) {
         controller = MediaController(context, mb.sessionToken).also {
             it.registerCallback(callback)
             update(it.metadata, it.playbackState)
+            _queue.value = queueOf(it.queue)
         }
         rootId = mb.root
         path.clear()
@@ -192,6 +209,20 @@ class CarMedia(private val context: Context) {
     private val callback = object : MediaController.Callback() {
         override fun onMetadataChanged(metadata: MediaMetadata?) = update(metadata, controller?.playbackState)
         override fun onPlaybackStateChanged(state: PlaybackState?) = update(controller?.metadata, state)
+        override fun onQueueChanged(queue: MutableList<MediaSession.QueueItem>?) {
+            _queue.value = queueOf(queue)
+        }
+    }
+
+    private fun queueOf(items: List<MediaSession.QueueItem>?): List<QueueTrack> = items.orEmpty().map { item ->
+        val d = item.description
+        QueueTrack(
+            queueId = item.queueId,
+            title = d.title?.toString().orEmpty(),
+            subtitle = d.subtitle?.toString().orEmpty(),
+            iconUri = d.iconUri,
+            iconBitmap = d.iconBitmap,
+        )
     }
 
     private fun update(metadata: MediaMetadata?, state: PlaybackState?) {
@@ -212,6 +243,7 @@ class CarMedia(private val context: Context) {
             actions = state?.actions ?: 0,
             custom = state?.customActions.orEmpty().map { CustomAction(it.action, it.name.toString(), it.extras) },
             error = state?.errorMessage?.toString(),
+            activeQueueItemId = state?.activeQueueItemId ?: MediaSession.QueueItem.UNKNOWN_ID.toLong(),
         )
     }
 
@@ -286,6 +318,7 @@ class CarMedia(private val context: Context) {
     fun previous() = controller?.transportControls?.skipToPrevious()
     fun seek(ms: Long) = controller?.transportControls?.seekTo(ms)
     fun custom(action: CustomAction) = controller?.transportControls?.sendCustomAction(action.id, action.extras)
+    fun playQueueItem(track: QueueTrack) = controller?.transportControls?.skipToQueueItem(track.queueId)
 
     fun disconnect() {
         connecting = null
@@ -298,6 +331,7 @@ class CarMedia(private val context: Context) {
         subscribed = null
         _phase.value = Phase.IDLE
         _now.value = NowPlaying()
+        _queue.value = emptyList()
     }
 
     private companion object {

gearslip/src/main/java/app/seb3thehacker/gearslip/media/MediaCatalog.kt

@@ -1,6 +1,7 @@
 package app.seb3thehacker.gearslip.media
 
 import app.seb3thehacker.gearslip.host.AndroidAuto
+import app.seb3thehacker.gearslip.host.KnownApps
 import android.content.ComponentName
 import android.content.Context
 import android.content.Intent
@@ -33,6 +34,7 @@ object MediaCatalog {
             .asSequence()
             .filter { it.serviceInfo.packageName != context.packageName }
             .filterNot { AndroidAuto.matches(it.serviceInfo.packageName, it.loadLabel(manager).toString()) }
+            .filterNot { KnownApps.isHidden(it.serviceInfo.packageName) }
             .filter { declaresCar(manager, it.serviceInfo) }
             .map {
                 val info = it.serviceInfo

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/CarPreviewScreen.kt

@@ -3,7 +3,7 @@ package app.seb3thehacker.gearslip.ui
 import android.app.Activity
 import android.content.Context
 import android.content.ContextWrapper
-import android.content.pm.ActivityInfo
+import android.content.res.Configuration
 import android.graphics.Bitmap
 import android.graphics.PixelFormat
 import android.hardware.HardwareBuffer
@@ -43,6 +43,7 @@ import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.input.pointer.pointerInteropFilter
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.layout.onSizeChanged
+import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
 import androidx.core.view.WindowInsetsCompat
@@ -70,7 +71,9 @@ fun CarPreviewScreen(onBack: () -> Unit) {
     val frame by CarEnvironment.frame.collectAsStateWithLifecycle()
     var bitmap by remember { mutableStateOf<Bitmap?>(null) }
     var viewSize by remember { mutableStateOf(0 to 0) }
-    var fullscreen by remember { mutableStateOf(false) }
+    // Tied to how the phone itself is held, not a button: turn it sideways and the preview goes
+    // fullscreen, turn it back and the phone's own chrome (the Back/title above the frame) returns.
+    val fullscreen = LocalConfiguration.current.orientation == Configuration.ORIENTATION_LANDSCAPE
 
     val width = frame.width
     val height = frame.height
@@ -149,7 +152,7 @@ fun CarPreviewScreen(onBack: () -> Unit) {
     }
 
     if (fullscreen) {
-        Fullscreen(landscape = width > height, onExit = { fullscreen = false }) {
+        Fullscreen(onBack) {
             // No fillMax here: left to the bounds alone, aspectRatio takes the whole width or the
             // whole height, whichever the car's shape allows, and the rest stays black.
             frameContent(Modifier)
@@ -174,7 +177,6 @@ fun CarPreviewScreen(onBack: () -> Unit) {
 
             Row {
                 TextButton(onClick = onBack) { Text("Back") }
-                TextButton(onClick = { fullscreen = true }) { Text("Fullscreen") }
             }
         }
     }
@@ -184,34 +186,32 @@ fun CarPreviewScreen(onBack: () -> Unit) {
  * Fills the phone screen with [content], centred and letterboxed.
  *
  * A car screen is wider than it is tall, so a portrait phone would waste most of its height on
- * one. While this is showing, the activity is turned to match and the system bars go away - both
- * are undone on the way out, so the rest of the phone UI is unaffected.
+ * one. This only shows once the phone is already turned sideways (the caller drives it off the
+ * phone's own orientation), so there is no rotation left to force here - just the system bars to
+ * hide while it's up and restore on the way out.
  */
 @Composable
 private fun Fullscreen(
-    landscape: Boolean,
-    onExit: () -> Unit,
+    onBack: () -> Unit,
     content: @Composable BoxScope.() -> Unit,
 ) {
     val activity = LocalContext.current.activity()
 
-    DisposableEffect(activity, landscape) {
+    DisposableEffect(activity) {
         if (activity == null) return@DisposableEffect onDispose { }
 
         val insets = WindowInsetsControllerCompat(activity.window, activity.window.decorView).apply {
             systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
             hide(WindowInsetsCompat.Type.systemBars())
         }
-        val previousOrientation = activity.requestedOrientation
-        if (landscape) activity.requestedOrientation = ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE
 
-        onDispose {
-            insets.show(WindowInsetsCompat.Type.systemBars())
-            activity.requestedOrientation = previousOrientation
-        }
+        onDispose { insets.show(WindowInsetsCompat.Type.systemBars()) }
     }
 
-    BackHandler(onBack = onExit)
+    // Turning the phone back upright is what normally leaves fullscreen; back still leaves the
+    // preview screen entirely rather than doing nothing, in case the phone's own rotation lock
+    // is on and turning it sideways/back isn't an option.
+    BackHandler(onBack = onBack)
 
     Box(
         Modifier.fillMaxSize().background(Color.Black),
@@ -222,10 +222,10 @@ private fun Fullscreen(
         // The frame swallows every touch inside it, so leaving needs either the back gesture or
         // a button of its own. This one sits in the corner the car UI leaves emptiest.
         FilledTonalIconButton(
-            onClick = onExit,
+            onClick = onBack,
             modifier = Modifier.align(Alignment.BottomStart).padding(8.dp),
         ) {
-            Icon(Icons.Filled.Close, contentDescription = "Leave fullscreen")
+            Icon(Icons.Filled.Close, contentDescription = "Leave the car preview")
         }
     }
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/CertSetupScreen.kt

@@ -0,0 +1,265 @@
+package app.seb3thehacker.gearslip.ui
+
+import android.net.Uri
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+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.RowScope
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.AppSettings
+import app.seb3thehacker.gearslip.CertProvider
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+
+/**
+ * Shown when Gearslip has no certificate loaded. Download is the one clear path; importing your
+ * own file is offered as a smaller, secondary option underneath it.
+ *
+ * The app ships no certificates. Skipping generates a self-signed one, which a real head unit
+ * rejects.
+ */
+@Composable
+fun CertSetupScreen(onDone: () -> Unit) {
+    val context = LocalContext.current
+    val scope = rememberCoroutineScope()
+
+    var downloadState by remember { mutableStateOf<DownloadState>(DownloadState.Idle) }
+    var showImport by remember { mutableStateOf(false) }
+    var pendingUri by remember { mutableStateOf<Uri?>(null) }
+    var manualProgress by remember { mutableStateOf(false) }
+
+    val importLauncher = rememberLauncherForActivityResult(ActivityResultContracts.OpenDocument()) { uri ->
+        if (uri != null) pendingUri = uri
+    }
+
+    val installed = manualProgress || downloadState is DownloadState.Success
+
+    Scaffold(containerColor = MaterialTheme.colorScheme.background) { padding ->
+        Column(
+            Modifier
+                .fillMaxSize()
+                .padding(padding)
+                .padding(horizontal = 24.dp)
+                .verticalScroll(rememberScrollState()),
+            horizontalAlignment = Alignment.CenterHorizontally,
+            verticalArrangement = Arrangement.Center,
+        ) {
+            Text(
+                "Certificate Setup",
+                style = MaterialTheme.typography.headlineLarge,
+                fontWeight = FontWeight.Bold,
+                color = MaterialTheme.colorScheme.onBackground,
+            )
+            Spacer(Modifier.height(8.dp))
+            Text(
+                if (installed) {
+                    "Cars accept only Google-issued certificates, and you have one loaded."
+                } else {
+                    "Cars accept only Google-issued certificates. Download one to connect."
+                },
+                style = MaterialTheme.typography.bodyLarge,
+                textAlign = TextAlign.Center,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+            Spacer(Modifier.height(32.dp))
+
+            if (installed) {
+                Text(
+                    if (manualProgress) "Certificate imported." else "Certificate installed.",
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.SemiBold,
+                    color = MaterialTheme.colorScheme.primary,
+                )
+                Spacer(Modifier.height(20.dp))
+                Button(onClick = onDone, modifier = Modifier.fillMaxWidth().height(56.dp)) {
+                    Text("Continue")
+                }
+                Spacer(Modifier.height(40.dp))
+                return@Column
+            }
+
+            when (downloadState) {
+                is DownloadState.Idle -> {
+                    Button(
+                        onClick = {
+                            downloadState = DownloadState.Loading
+                            scope.launch {
+                                val result = withContext(Dispatchers.IO) {
+                                    runCatching { CertProvider.downloadAndImport(context) }
+                                }
+                                downloadState = result.fold(
+                                    onSuccess = { DownloadState.Success(it.certificate.subjectX500Principal.name) },
+                                    onFailure = { DownloadState.Error(it.message ?: "Unknown error") },
+                                )
+                            }
+                        },
+                        modifier = Modifier.fillMaxWidth().height(56.dp),
+                    ) {
+                        Text("Download certificate")
+                    }
+                    Text(
+                        "Works with most cars built before 2020. Newer cars reject it.",
+                        style = MaterialTheme.typography.bodySmall,
+                        textAlign = TextAlign.Center,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        modifier = Modifier.padding(top = 8.dp),
+                    )
+                }
+
+                is DownloadState.Loading -> {
+                    Box(Modifier.fillMaxWidth().height(56.dp), contentAlignment = Alignment.Center) {
+                        DownloadingRow {
+                            CircularProgressIndicator(Modifier.size(20.dp), strokeWidth = 2.dp)
+                            Text("Downloading…", style = MaterialTheme.typography.bodyLarge)
+                        }
+                    }
+                }
+
+                is DownloadState.Success -> Unit // handled above via `installed`
+
+                is DownloadState.Error -> {
+                    Surface(color = MaterialTheme.colorScheme.errorContainer, shape = MaterialTheme.shapes.medium) {
+                        Column(Modifier.fillMaxWidth().padding(16.dp), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                            Text(
+                                "Download failed",
+                                style = MaterialTheme.typography.titleMedium,
+                                fontWeight = FontWeight.SemiBold,
+                                color = MaterialTheme.colorScheme.onErrorContainer,
+                            )
+                            Text(
+                                (downloadState as DownloadState.Error).message,
+                                style = MaterialTheme.typography.bodySmall,
+                                color = MaterialTheme.colorScheme.onErrorContainer,
+                            )
+                            Button(onClick = { downloadState = DownloadState.Idle }, modifier = Modifier.fillMaxWidth()) {
+                                Text("Retry")
+                            }
+                        }
+                    }
+                }
+            }
+
+            Spacer(Modifier.height(16.dp))
+
+            if (showImport) {
+                OutlinedButton(
+                    onClick = { importLauncher.launch(arrayOf("*/*")) },
+                    modifier = Modifier.fillMaxWidth().height(52.dp),
+                ) { Text("Import your own .p12 cert") }
+                Spacer(Modifier.height(16.dp))
+            } else {
+                TextButton(onClick = { showImport = true }) { Text("Import your own certificate instead") }
+                Spacer(Modifier.height(8.dp))
+            }
+
+            OutlinedButton(
+                onClick = {
+                    AppSettings.setSkippedCertSetup(context)
+                    onDone()
+                },
+                modifier = Modifier.fillMaxWidth().height(52.dp),
+            ) {
+                Text("Skip car connection setup")
+            }
+
+            Spacer(Modifier.height(40.dp))
+        }
+    }
+
+    pendingUri?.let { uri ->
+        PasswordDialog(
+            onDismiss = { pendingUri = null },
+            onConfirm = { password, reportError ->
+                scope.launch {
+                    val result = withContext(Dispatchers.IO) {
+                        runCatching { CertProvider.importFrom(context, uri, password) }
+                    }
+                    result.onSuccess {
+                        pendingUri = null
+                        manualProgress = true
+                    }.onFailure {
+                        reportError("Wrong password or not a valid PKCS#12 file with a private key.")
+                    }
+                }
+            },
+        )
+    }
+}
+
+/** A tight horizontal row for the inline "Downloading…" spinner state. */
+@Composable
+private fun DownloadingRow(content: @Composable RowScope.() -> Unit) {
+    Row(
+        horizontalArrangement = Arrangement.spacedBy(10.dp),
+        verticalAlignment = Alignment.CenterVertically,
+        content = content,
+    )
+}
+
+private sealed class DownloadState {
+    data object Idle : DownloadState()
+    data object Loading : DownloadState()
+    data class Success(val subjectName: String) : DownloadState()
+    data class Error(val message: String) : DownloadState()
+}
+
+@Composable
+private fun PasswordDialog(onDismiss: () -> Unit, onConfirm: (String, (String) -> Unit) -> Unit) {
+    var password by remember { mutableStateOf("") }
+    var error by remember { mutableStateOf<String?>(null) }
+
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text("Certificate password") },
+        text = {
+            OutlinedTextField(
+                value = password,
+                onValueChange = { password = it; error = null },
+                singleLine = true,
+                label = { Text("Password") },
+                visualTransformation = PasswordVisualTransformation(),
+                keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Password),
+                isError = error != null,
+                supportingText = { Text(error ?: "Leave empty if the file has none.") },
+            )
+        },
+        confirmButton = { TextButton(onClick = { onConfirm(password) { error = it } }) { Text("Import") } },
+        dismissButton = { TextButton(onClick = onDismiss) { Text("Cancel") } },
+    )
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/CertSummary.kt

@@ -19,12 +19,17 @@ data class CertSummary(
             val identity = CertProvider.loadSupplied(context)
                 ?: return CertSummary(
                     CertProvider.Kind.SELF_SIGNED,
-                    "None loaded - a self-signed one is generated, which real head units reject",
+                    "None loaded (self-signed; cars reject it)",
                     null, null, null,
                 )
             val cert = identity.certificate
             val name = friendlyName(cert.subjectX500Principal.name)
-            val prefix = if (identity.kind == CertProvider.Kind.IMPORTED) "Imported" else "Staged over adb"
+            val prefix = when (identity.kind) {
+                    CertProvider.Kind.IMPORTED -> "Imported"
+                    CertProvider.Kind.DOWNLOADED -> "Downloaded"
+                    CertProvider.Kind.ADB_STAGED -> "Staged over adb"
+                    CertProvider.Kind.SELF_SIGNED -> "Self-signed"
+                }
             return CertSummary(
                 identity.kind,
                 "$prefix: $name",

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/CopyableCommand.kt

@@ -0,0 +1,50 @@
+package app.seb3thehacker.gearslip.ui
+
+import android.widget.Toast
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
+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.ui.Modifier
+import androidx.compose.ui.platform.LocalClipboardManager
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.unit.dp
+
+/**
+ * A command to run on a computer, shown so it can be copied rather than retyped. Tapping it puts
+ * it on the clipboard, which is the only way it reaches the computer from here anyway.
+ */
+@Composable
+fun CopyableCommand(command: String) {
+    val clipboard = LocalClipboardManager.current
+    val context = LocalContext.current
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHighest,
+        shape = MaterialTheme.shapes.small,
+        onClick = {
+            clipboard.setText(AnnotatedString(command))
+            Toast.makeText(context, "Command copied", Toast.LENGTH_SHORT).show()
+        },
+        modifier = Modifier.fillMaxWidth().padding(top = 4.dp),
+    ) {
+        Column(Modifier.padding(horizontal = 12.dp, vertical = 10.dp), verticalArrangement = Arrangement.spacedBy(6.dp)) {
+            Text(
+                command,
+                style = MaterialTheme.typography.bodySmall,
+                fontFamily = FontFamily.Monospace,
+                color = MaterialTheme.colorScheme.onSurface,
+            )
+            Text(
+                "Tap to copy",
+                style = MaterialTheme.typography.labelSmall,
+                color = MaterialTheme.colorScheme.primary,
+            )
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/GearslipApp.kt

@@ -7,17 +7,32 @@ import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.platform.LocalContext
 import app.seb3thehacker.gearslip.AppSettings
+import app.seb3thehacker.gearslip.CertProvider
 
-private enum class Screen { HOME, LOGS, SETTINGS, CAR_PREVIEW }
+private enum class Screen { HOME, LOGS, SETTINGS, CAR_PREVIEW, CERT_SETUP, SETUP_GUIDE, HELP }
 
 /** Three screens and a back stack of depth one: no navigation library needed. */
 @Composable
-fun GearslipApp(onDisconnect: () -> Unit) {
-    var screen by rememberSaveable { mutableStateOf(Screen.HOME) }
+fun GearslipApp(onDisconnect: () -> Unit, onRequestCallScreening: () -> Unit) {
+    val context = LocalContext.current
+    val needsCertSetup = remember {
+        !AppSettings.hasSkippedCertSetup(context) && !CertProvider.hasAnyCert(context)
+    }
+    val needsSetupGuide = remember { !AppSettings.hasSeenPermissionsSetup(context) }
+    var screen by rememberSaveable {
+        mutableStateOf(
+            when {
+                needsCertSetup -> Screen.CERT_SETUP
+                needsSetupGuide -> Screen.SETUP_GUIDE
+                else -> Screen.HOME
+            },
+        )
+    }
     BackHandler(enabled = screen != Screen.HOME) { screen = Screen.HOME }
 
     when (screen) {
@@ -25,11 +40,22 @@ fun GearslipApp(onDisconnect: () -> Unit) {
             onOpenLogs = { screen = Screen.LOGS },
             onOpenSettings = { screen = Screen.SETTINGS },
             onOpenCarPreview = { screen = Screen.CAR_PREVIEW },
+            onOpenHelp = { screen = Screen.HELP },
             onDisconnect = onDisconnect,
         )
         Screen.LOGS -> LogsScreen(onBack = { screen = Screen.HOME })
         Screen.SETTINGS -> SettingsScreen(onBack = { screen = Screen.HOME })
         Screen.CAR_PREVIEW -> CarPreviewScreen(onBack = { screen = Screen.HOME })
+        Screen.HELP -> HelpScreen(onBack = { screen = Screen.HOME }, onRequestCallScreening = onRequestCallScreening)
+        Screen.CERT_SETUP -> CertSetupScreen(
+            onDone = {
+                screen = if (AppSettings.hasSeenPermissionsSetup(context)) Screen.HOME else Screen.SETUP_GUIDE
+            },
+        )
+        Screen.SETUP_GUIDE -> SetupGuideScreen(
+            onRequestCallScreening = onRequestCallScreening,
+            onDone = { screen = Screen.HOME },
+        )
     }
 
     CompatWarning()
@@ -47,9 +73,8 @@ private fun CompatWarning() {
             title = { Text("Before you plug in") },
             text = {
                 Text(
-                    "Gearslip may not connect on cars or head units newer than about 2020. " +
-                        "Older systems are more likely to work; newer firmware often rejects the " +
-                        "connection outright.",
+                    "Gearslip works with cars built before 2020. " +
+                        "Newer firmware often blocks the connection.",
                 )
             },
             confirmButton = {

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/HelpScreen.kt

@@ -0,0 +1,157 @@
+package app.seb3thehacker.gearslip.ui
+
+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.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+
+/**
+ * One step of the setup list: a sentence that says what to do, and optionally how.
+ *
+ * [command] is for a step that cannot be done on the phone; it is shown as something to copy
+ * rather than to read, because a mistyped package name fails silently. [onClick] is for a step
+ * that can, in one tap, in which case it is shown as a button instead.
+ */
+private class Step(
+    val action: String,
+    val detail: String? = null,
+    val command: String? = null,
+    val buttonLabel: String? = null,
+    val onClick: (() -> Unit)? = null,
+)
+
+private fun setupSteps(onRequestCallScreening: () -> Unit) = listOf(
+    Step("Use a car from 2020 or earlier.", "Newer head units reject the certificate."),
+    Step(
+        "On GrapheneOS, exempt Gearslip from exploit protections.",
+        "Open Settings, then Apps, then Gearslip, and turn on Exploit protection compatibility mode.",
+    ),
+    Step("Disable or uninstall the Android Auto app."),
+    Step("Load a certificate.", "Open Settings, then download or import a certificate."),
+    Step(
+        "Allow the microphone, so music can reach the car.",
+        "Android asks for the microphone before it will let any app pass music along. " +
+            "Gearslip never listens to you: it copies what a music app is playing, and nothing else.",
+    ),
+    Step(
+        "Optional: stop Android asking about audio every drive.",
+        "Connect the phone to a computer with USB debugging turned on, and run this command. " +
+            "It tells Android to trust Gearslip with audio from now on. Skip it and everything " +
+            "still works, but you have to tap Start once each time you set off.",
+        command = "adb shell appops set app.seb3thehacker.gearslip PROJECT_MEDIA allow",
+    ),
+    Step(
+        "Optional: keep notifications readable while music plays.",
+        "Android treats sending audio to the car like sharing your screen, and hides what your " +
+            "notifications say. Run this command too, and Gearslip switches that off only while " +
+            "music is going to the car, then puts it back.",
+        command = "adb shell pm grant app.seb3thehacker.gearslip android.permission.WRITE_SECURE_SETTINGS",
+    ),
+    Step(
+        "Optional: let the car screen answer and decline calls.",
+        "This sets Gearslip as your phone's caller ID and spam-blocking app, the same kind of " +
+            "consent a call-blocking app asks for. Without it, calls still ring, but only the " +
+            "phone itself can answer or decline them.",
+        buttonLabel = "Set up",
+        onClick = onRequestCallScreening,
+    ),
+    Step("Plug the phone into the car.", "Gearslip opens by itself when the head unit connects."),
+)
+
+/** The full setup reference, behind the help button: what the one-time guide walks through, kept
+ * here too so it can be reread without repeating the guide itself. */
+@Composable
+fun HelpScreen(onBack: () -> Unit, onRequestCallScreening: () -> Unit) {
+    val steps = remember(onRequestCallScreening) { setupSteps(onRequestCallScreening) }
+
+    Scaffold(containerColor = MaterialTheme.colorScheme.background) { padding ->
+        Column(
+            Modifier
+                .fillMaxSize()
+                .padding(padding)
+                .padding(horizontal = 24.dp)
+                .verticalScroll(rememberScrollState()),
+        ) {
+            Spacer(Modifier.height(24.dp))
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                IconButton(onClick = onBack) { Text("‹", style = MaterialTheme.typography.headlineMedium) }
+                Text(
+                    "How to connect",
+                    style = MaterialTheme.typography.headlineSmall,
+                    fontWeight = FontWeight.Bold,
+                    color = MaterialTheme.colorScheme.onBackground,
+                )
+            }
+            Spacer(Modifier.height(16.dp))
+            Column(verticalArrangement = Arrangement.spacedBy(18.dp)) {
+                steps.forEachIndexed { index, step ->
+                    Row(horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+                        Text(
+                            "${index + 1}",
+                            style = MaterialTheme.typography.titleMedium,
+                            fontWeight = FontWeight.Bold,
+                            color = MaterialTheme.colorScheme.primary,
+                            modifier = Modifier.width(16.dp),
+                        )
+                        Column(verticalArrangement = Arrangement.spacedBy(4.dp)) {
+                            Text(step.action, style = MaterialTheme.typography.bodyLarge, fontWeight = FontWeight.SemiBold)
+                            step.detail?.let {
+                                Text(
+                                    it,
+                                    style = MaterialTheme.typography.bodyMedium,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                )
+                            }
+                            step.command?.let { CopyableCommand(it) }
+                            if (step.onClick != null) {
+                                FilledTonalButton(onClick = step.onClick, modifier = Modifier.padding(top = 4.dp)) {
+                                    Text(step.buttonLabel ?: "Open")
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+            Spacer(Modifier.height(32.dp))
+        }
+    }
+}
+
+/** The small circular "?" button that opens [HelpScreen] from the top right of the home screen. */
+@Composable
+fun HelpButton(onClick: () -> Unit) {
+    Surface(
+        onClick = onClick,
+        shape = MaterialTheme.shapes.extraLarge,
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+    ) {
+        Box(Modifier.padding(10.dp), contentAlignment = Alignment.Center) {
+            Text(
+                "?",
+                style = MaterialTheme.typography.titleMedium,
+                fontWeight = FontWeight.Bold,
+                color = MaterialTheme.colorScheme.onSurface,
+            )
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/HomeScreen.kt

@@ -1,9 +1,6 @@
 package app.seb3thehacker.gearslip.ui
 
 import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.width
-import androidx.compose.foundation.layout.widthIn
-import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -43,6 +40,7 @@ fun HomeScreen(
     onOpenLogs: () -> Unit,
     onOpenSettings: () -> Unit,
     onOpenCarPreview: () -> Unit,
+    onOpenHelp: () -> Unit,
     onDisconnect: () -> Unit,
 ) {
     val status by SessionStatus.state.collectAsStateWithLifecycle()
@@ -62,22 +60,25 @@ fun HomeScreen(
                     .verticalScroll(rememberScrollState()),
             ) {
                 Spacer(Modifier.height(24.dp))
-                Text(
-                    "Gearslip",
-                    style = MaterialTheme.typography.displayLarge,
-                    fontWeight = FontWeight.Bold,
-                    color = MaterialTheme.colorScheme.onBackground,
-                )
-                Text(
-                    "v${LocalContext.current.appVersionName()}",
-                    style = MaterialTheme.typography.labelLarge,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                )
+                Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceBetween) {
+                    Column {
+                        Text(
+                            "Gearslip",
+                            style = MaterialTheme.typography.displayLarge,
+                            fontWeight = FontWeight.Bold,
+                            color = MaterialTheme.colorScheme.onBackground,
+                        )
+                        Text(
+                            "v${LocalContext.current.appVersionName()}",
+                            style = MaterialTheme.typography.labelLarge,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        )
+                    }
+                    HelpButton(onClick = onOpenHelp)
+                }
                 Spacer(Modifier.height(16.dp))
                 StatusCard(status)
                 Spacer(Modifier.height(24.dp))
-                SetupSteps()
-                Spacer(Modifier.height(24.dp))
                 Row(
                     Modifier.fillMaxWidth(),
                     verticalAlignment = Alignment.CenterVertically,
@@ -178,61 +179,3 @@ private fun StatusCard(status: SessionStatus.Snapshot) {
 private fun Context.appVersionName(): String =
     runCatching { packageManager.getPackageInfo(packageName, 0).versionName }.getOrNull() ?: "?"
 
-/** One step of the setup list: a sentence that says what to do, and optionally how. */
-private class Step(val action: String, val detail: String? = null)
-
-private val SETUP_STEPS = listOf(
-    Step("Use a car from 2020 or earlier.", "Newer head units reject the certificate."),
-    Step(
-        "On GrapheneOS, exempt Gearslip from exploit protections.",
-        "Open Settings, then Apps, then Gearslip, and turn on Exploit protection compatibility mode.",
-    ),
-    Step("Disable or uninstall the Android Auto app."),
-    Step("Load the certificate.", "Open Settings and choose Import certificate."),
-    Step("Plug the phone into the car.", "Gearslip opens by itself when the head unit connects."),
-)
-
-/**
- * What to do before the first drive, in order. Kept in a narrow card with room at the sides so
- * the lines stay short enough to read at a glance.
- */
-@Composable
-private fun SetupSteps() {
-    Box(Modifier.fillMaxWidth(), contentAlignment = Alignment.Center) {
-        Surface(
-            color = MaterialTheme.colorScheme.surfaceContainerLow,
-            shape = MaterialTheme.shapes.extraLarge,
-            modifier = Modifier.widthIn(max = 560.dp).padding(horizontal = 16.dp),
-        ) {
-            Column(Modifier.padding(horizontal = 24.dp, vertical = 22.dp), verticalArrangement = Arrangement.spacedBy(18.dp)) {
-                Text(
-                    "How to connect",
-                    style = MaterialTheme.typography.titleLarge,
-                    fontWeight = FontWeight.SemiBold,
-                    color = MaterialTheme.colorScheme.onSurface,
-                )
-                SETUP_STEPS.forEachIndexed { index, step ->
-                    Row(horizontalArrangement = Arrangement.spacedBy(16.dp)) {
-                        Text(
-                            "${index + 1}",
-                            style = MaterialTheme.typography.titleMedium,
-                            fontWeight = FontWeight.Bold,
-                            color = MaterialTheme.colorScheme.primary,
-                            modifier = Modifier.width(16.dp),
-                        )
-                        Column(verticalArrangement = Arrangement.spacedBy(4.dp)) {
-                            Text(step.action, style = MaterialTheme.typography.bodyLarge, fontWeight = FontWeight.SemiBold)
-                            step.detail?.let {
-                                Text(
-                                    it,
-                                    style = MaterialTheme.typography.bodyMedium,
-                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                )
-                            }
-                        }
-                    }
-                }
-            }
-        }
-    }
-}

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/SettingsScreen.kt

@@ -18,6 +18,7 @@ import androidx.compose.material.icons.automirrored.filled.ArrowBack
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Button
 import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.FilledTonalButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -124,6 +125,26 @@ private fun CertificateSection() {
         Button(onClick = { picker.launch(arrayOf("*/*")) }, modifier = Modifier.fillMaxWidth().height(52.dp)) {
             Text("Import certificate (.p12)")
         }
+
+        FilledTonalButton(
+            onClick = {
+                scope.launch {
+                    val result = withContext(Dispatchers.IO) {
+                        runCatching { CertProvider.downloadAndImport(context) }
+                    }
+                    result.onSuccess {
+                        notice = "Certificate downloaded."
+                        refresh++
+                    }.onFailure {
+                        notice = "Download failed: ${it.message}"
+                    }
+                }
+            },
+            modifier = Modifier.fillMaxWidth().height(52.dp),
+        ) {
+            Text("Download certificate")
+        }
+
         if (summary?.kind == CertProvider.Kind.IMPORTED) {
             OutlinedButton(
                 onClick = {
@@ -134,9 +155,21 @@ private fun CertificateSection() {
                 modifier = Modifier.fillMaxWidth().height(52.dp),
             ) { Text("Remove imported certificate") }
         }
+
+        if (summary?.kind == CertProvider.Kind.DOWNLOADED) {
+            OutlinedButton(
+                onClick = {
+                    CertProvider.removeDownloaded(context)
+                    notice = "Removed the downloaded certificate."
+                    refresh++
+                },
+                modifier = Modifier.fillMaxWidth().height(52.dp),
+            ) { Text("Remove downloaded certificate") }
+        }
+
         notice?.let { Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant) }
         Text(
-            "An imported certificate takes priority over one staged over adb. Takes effect on the next connection.",
+            "Changes take effect on the next connection.",
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/SetupGuideScreen.kt

@@ -0,0 +1,379 @@
+package app.seb3thehacker.gearslip.ui
+
+import android.Manifest
+import android.app.AppOpsManager
+import android.app.NotificationManager
+import android.app.role.RoleManager
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.net.Uri
+import android.provider.Settings
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.LinearProgressIndicator
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+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.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.AppSettings
+import app.seb3thehacker.gearslip.call.CarCalls
+import app.seb3thehacker.gearslip.car.CarSettings
+import app.seb3thehacker.gearslip.car.Prefetch
+import app.seb3thehacker.gearslip.host.AndroidAuto
+import app.seb3thehacker.gearslip.notify.GearslipNotificationListener
+
+/**
+ * One page of the guide. [permissions] drives a system permission dialog; [command] is an adb
+ * command to copy; [actionLabel] with [onAction] is a button that does something else (opens a
+ * settings screen) without by itself finishing the page. Everything is skippable: none of this
+ * can be verified as done, only offered.
+ */
+private class GuidePage(
+    val title: String,
+    val explanation: String,
+    val permissions: Array<String>? = null,
+    val command: String? = null,
+    val actionLabel: String? = null,
+    val onAction: (() -> Unit)? = null,
+)
+
+/** True once every permission in [permissions] is already granted - nothing left for this page to do. */
+private fun granted(context: Context, permissions: Array<String>): Boolean =
+    permissions.all { context.checkSelfPermission(it) == PackageManager.PERMISSION_GRANTED }
+
+/** Whether Gearslip already holds the hidden `PROJECT_MEDIA` app-op an adb command grants -
+ * checked the same way the platform checks it, since there is no public permission for it. */
+private fun hasProjectMediaOp(context: Context): Boolean {
+    val ops = context.getSystemService(AppOpsManager::class.java) ?: return false
+    val mode = runCatching {
+        ops.unsafeCheckOpNoThrow("android:project_media", android.os.Process.myUid(), context.packageName)
+    }.getOrDefault(AppOpsManager.MODE_IGNORED)
+    return mode == AppOpsManager.MODE_ALLOWED
+}
+
+private fun hasCallScreeningRole(context: Context): Boolean {
+    val roleManager = context.getSystemService(RoleManager::class.java) ?: return false
+    return runCatching { roleManager.isRoleHeld(RoleManager.ROLE_CALL_SCREENING) }.getOrDefault(false)
+}
+
+/** Whether the driver has already granted Gearslip's [GearslipNotificationListener] access. */
+private fun hasNotificationAccess(context: Context): Boolean {
+    val manager = context.getSystemService(NotificationManager::class.java) ?: return false
+    val component = ComponentName(context, GearslipNotificationListener::class.java)
+    return runCatching { manager.isNotificationListenerAccessGranted(component) }.getOrDefault(false)
+}
+
+private fun pages(context: Context, onRequestCallScreening: () -> Unit): List<GuidePage> = buildList {
+    // --- Permissions: skipped outright once already granted, nothing left to ask -----
+    if (CarSettings.pipeAudio.value && !granted(context, arrayOf(Manifest.permission.RECORD_AUDIO))) {
+        add(
+            GuidePage(
+                title = "Microphone",
+                explanation = "Android will not pass a music app's audio to the car without this " +
+                    "permission. Gearslip does not listen to you: it copies what is already " +
+                    "playing, nothing else.",
+                permissions = arrayOf(Manifest.permission.RECORD_AUDIO),
+            ),
+        )
+    }
+    if (!granted(context, arrayOf(Manifest.permission.ACCESS_FINE_LOCATION))) {
+        add(
+            GuidePage(
+                title = "Location",
+                explanation = "The car's map and nearby places need to know where you are. " +
+                    "Without it, the dashboard has no map card.",
+                permissions = arrayOf(Manifest.permission.ACCESS_FINE_LOCATION),
+            ),
+        )
+    }
+    if (!granted(context, arrayOf(Manifest.permission.READ_CALENDAR))) {
+        add(
+            GuidePage(
+                title = "Calendar",
+                explanation = "Gearslip reads your next event to show an agenda card on the car " +
+                    "screen. It only reads; it never edits or deletes anything.",
+                permissions = arrayOf(Manifest.permission.READ_CALENDAR),
+            ),
+        )
+    }
+    val callPermissions = arrayOf(
+        Manifest.permission.READ_PHONE_STATE,
+        Manifest.permission.READ_CALL_LOG,
+        Manifest.permission.READ_CONTACTS,
+        Manifest.permission.ANSWER_PHONE_CALLS,
+        Manifest.permission.CALL_PHONE,
+    )
+    if (!granted(context, callPermissions)) {
+        add(
+            GuidePage(
+                title = "Phone and contacts",
+                explanation = "When a call comes in, Gearslip matches the number against your " +
+                    "contacts, so the car screen can show a name instead of just digits. The " +
+                    "same permissions let the car screen's Phone app dial a number or call " +
+                    "someone from your contacts.",
+                permissions = callPermissions,
+            ),
+        )
+    }
+
+    if (!hasNotificationAccess(context)) {
+        add(
+            GuidePage(
+                title = "Notification access",
+                explanation = "The car screen shows your phone's notifications and lets you " +
+                    "reply from there. Android only allows that once you grant Gearslip access, " +
+                    "from the list this opens - it needs this to work at all.",
+                actionLabel = "Open notification access",
+                onAction = {
+                    context.startActivity(Intent(Settings.ACTION_NOTIFICATION_LISTENER_SETTINGS))
+                },
+            ),
+        )
+    }
+
+    // --- GrapheneOS ------------------------------------------------------------------
+    add(
+        GuidePage(
+            title = "GrapheneOS exploit protection",
+            explanation = "On GrapheneOS only: open Gearslip's app settings and turn on Exploit " +
+                "protection compatibility mode. Gearslip's native USB and video code trips " +
+                "GrapheneOS's hardened memory checks otherwise. Skip this on any other Android.",
+            actionLabel = "Open app settings",
+            onAction = {
+                context.startActivity(
+                    Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", context.packageName, null)),
+                )
+            },
+        ),
+    )
+
+    // --- Android Auto ------------------------------------------------------------------
+    val androidAutoPackage = AndroidAuto.installedPackage(context)
+        ?.takeIf { AndroidAuto.isActive(context, it) }
+    if (androidAutoPackage != null) {
+        add(
+            GuidePage(
+                title = "Remove Android Auto",
+                explanation = "Android Auto is still installed. It claims the same USB " +
+                    "connection Gearslip needs, so the two fight over it. Disable or uninstall " +
+                    "it from the app info screen this opens.",
+                actionLabel = "Open Android Auto's app info",
+                onAction = {
+                    context.startActivity(
+                        Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", androidAutoPackage, null)),
+                    )
+                },
+            ),
+        )
+    }
+
+    // --- Default handler ---------------------------------------------------------------
+    add(
+        GuidePage(
+            title = "Make Gearslip the default",
+            explanation = "Android has no separate default-app setting for a USB accessory like " +
+                "the car. It just launches whichever single app matches - which is Gearslip, " +
+                "now that Android Auto is out of the way. If a chooser still appears when you " +
+                "plug in, pick Gearslip and tap Always so Android stops asking.",
+        ),
+    )
+
+    // --- Optional: each is skipped once its actual effect is already in place --------
+    if (!hasProjectMediaOp(context)) {
+        add(
+            GuidePage(
+                title = "Optional: trust audio every drive",
+                explanation = "Connect the phone to a computer with USB debugging on, and run this " +
+                    "command. It tells Android to trust Gearslip with audio from now on. Skip it " +
+                    "and everything still works, but you tap Start once each time you set off.",
+                command = "adb shell appops set app.seb3thehacker.gearslip PROJECT_MEDIA allow",
+            ),
+        )
+    }
+    if (!granted(context, arrayOf(Manifest.permission.WRITE_SECURE_SETTINGS))) {
+        add(
+            GuidePage(
+                title = "Optional: keep notifications readable",
+                explanation = "Android treats sending audio to the car like sharing your screen, and " +
+                    "hides what your notifications say. This command switches that off only while " +
+                    "music is going to the car, then puts it back.",
+                command = "adb shell pm grant app.seb3thehacker.gearslip android.permission.WRITE_SECURE_SETTINGS",
+            ),
+        )
+    }
+    if (!hasCallScreeningRole(context)) {
+        add(
+            GuidePage(
+                title = "Optional: answer and decline calls",
+                explanation = "This sets Gearslip as your phone's caller ID and spam-blocking app, " +
+                    "the same kind of consent a call-blocking app asks for. Without it, calls still " +
+                    "ring, but only the phone itself can answer or decline them.",
+                actionLabel = "Set up",
+                onAction = onRequestCallScreening,
+            ),
+        )
+    }
+}
+
+/**
+ * The first-run guide, one page at a time: permissions, then GrapheneOS's exploit-protection
+ * toggle, then removing Android Auto if it is still installed, then the optional extras. Nothing
+ * here can be verified as done except a permission grant, so every other page is a "Next" a
+ * driver takes on trust, with "Skip" sitting right next to it.
+ */
+@Composable
+fun SetupGuideScreen(onRequestCallScreening: () -> Unit, onDone: () -> Unit) {
+    val context = LocalContext.current
+    val pages = remember { pages(context, onRequestCallScreening) }
+    var index by remember { mutableIntStateOf(0) }
+
+    // Only ours to handle once there is a previous page to return to; at the first page, the
+    // system back press falls through to whatever the screen beneath this one does with it.
+    BackHandler(enabled = index > 0) { index -= 1 }
+
+    val launcher = rememberLauncherForActivityResult(
+        ActivityResultContracts.RequestMultiplePermissions(),
+    ) { result ->
+        if (result.values.any { it }) {
+            Prefetch.warm(context, force = true)
+            CarCalls.start(context)
+        }
+        index += 1
+    }
+
+    val page = pages.getOrNull(index)
+    if (page == null) {
+        AppSettings.setSeenPermissionsSetup(context)
+        onDone()
+        return
+    }
+
+    val alreadyGranted = page.permissions?.all {
+        context.checkSelfPermission(it) == PackageManager.PERMISSION_GRANTED
+    } ?: false
+
+    Scaffold(containerColor = MaterialTheme.colorScheme.background) { padding ->
+        Column(
+            Modifier
+                .fillMaxSize()
+                .padding(padding)
+                .padding(horizontal = 24.dp),
+            horizontalAlignment = Alignment.CenterHorizontally,
+            verticalArrangement = Arrangement.Center,
+        ) {
+            LinearProgressIndicator(
+                progress = { (index + 1f) / pages.size },
+                modifier = Modifier.fillMaxWidth().height(10.dp).clip(MaterialTheme.shapes.extraLarge),
+            )
+            Spacer(Modifier.height(12.dp))
+            Text(
+                "${index + 1} of ${pages.size}",
+                style = MaterialTheme.typography.titleMedium,
+                fontWeight = FontWeight.SemiBold,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+            Spacer(Modifier.height(48.dp))
+
+            Surface(color = MaterialTheme.colorScheme.surfaceContainerLow, shape = MaterialTheme.shapes.extraLarge) {
+                Column(Modifier.fillMaxWidth().padding(24.dp), verticalArrangement = Arrangement.spacedBy(12.dp)) {
+                    Text(
+                        page.title,
+                        style = MaterialTheme.typography.headlineSmall,
+                        fontWeight = FontWeight.Bold,
+                        color = MaterialTheme.colorScheme.onSurface,
+                    )
+                    Text(
+                        page.explanation,
+                        style = MaterialTheme.typography.bodyLarge,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                    page.command?.let { CopyableCommand(it) }
+                }
+            }
+
+            Spacer(Modifier.height(32.dp))
+
+            when {
+                page.permissions != null && alreadyGranted -> {
+                    Text(
+                        "Already allowed.",
+                        style = MaterialTheme.typography.bodyMedium,
+                        color = MaterialTheme.colorScheme.primary,
+                    )
+                    Spacer(Modifier.height(16.dp))
+                    PrimaryRow(showBack = index > 0, onBack = { index -= 1 }) {
+                        Button(onClick = { index += 1 }, modifier = it) { Text("Next") }
+                    }
+                }
+                page.permissions != null -> {
+                    PrimaryRow(showBack = index > 0, onBack = { index -= 1 }) {
+                        Button(onClick = { launcher.launch(page.permissions) }, modifier = it) { Text("Allow") }
+                    }
+                    Spacer(Modifier.height(8.dp))
+                    TextButton(onClick = { index += 1 }) { Text("Skip for now") }
+                }
+                page.onAction != null -> {
+                    FilledTonalButton(
+                        onClick = page.onAction,
+                        modifier = Modifier.fillMaxWidth().height(52.dp),
+                    ) { Text(page.actionLabel ?: "Open") }
+                    Spacer(Modifier.height(8.dp))
+                    PrimaryRow(showBack = index > 0, onBack = { index -= 1 }) {
+                        Button(onClick = { index += 1 }, modifier = it) { Text("Next") }
+                    }
+                }
+                else -> {
+                    PrimaryRow(showBack = index > 0, onBack = { index -= 1 }) {
+                        Button(onClick = { index += 1 }, modifier = it) { Text("Next") }
+                    }
+                }
+            }
+        }
+    }
+}
+
+/**
+ * The bottom action row: a lower-emphasis Back on the left once there is a previous page, and the
+ * page's own primary button - passed [content] so the caller keeps the button's own label and
+ * click behavior - filling the rest of the width.
+ */
+@Composable
+private fun PrimaryRow(showBack: Boolean, onBack: () -> Unit, content: @Composable (Modifier) -> Unit) {
+    if (showBack) {
+        Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+            OutlinedButton(
+                onClick = onBack,
+                modifier = Modifier.weight(1f).height(52.dp),
+            ) { Text("Back") }
+            content(Modifier.weight(1f).height(52.dp))
+        }
+    } else {
+        content(Modifier.fillMaxWidth().height(52.dp))
+    }
+}

gearslip/src/test/java/app/seb3thehacker/gearslip/ServiceDiscoveryAudioTest.kt

@@ -0,0 +1,94 @@
+package app.seb3thehacker.gearslip
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Test
+
+/**
+ * Parses the ServiceDiscoveryResponse the 2018 Uconnect actually sent, rebuilt field for field
+ * from the decoded tree in `archive/spike/car-run-2026-09-16-run2.log`.
+ *
+ * The car offers two audio sinks - media on channel 5 and guidance on channel 6 - alongside the
+ * video sink on channel 1 and a microphone source on channel 3. Picking the right one out of that
+ * set is the whole job of [ServiceDiscovery.findAudioServices], and getting it wrong is silent:
+ * audio simply never arrives.
+ */
+class ServiceDiscoveryAudioTest {
+
+    private fun varint(value: Long): ByteArray = Protobuf.varint(value)
+
+    private fun varintField(field: Int, value: Long) = Protobuf.varintField(field, value)
+
+    private fun lenField(field: Int, body: ByteArray): ByteArray =
+        varint(((field shl 3) or 2).toLong()) + varint(body.size.toLong()) + body
+
+    /** AudioConfiguration { sampling_rate = 1; bits = 2; channels = 3 } */
+    private fun audioConfig(rate: Int, bits: Int, channels: Int) =
+        varintField(1, rate.toLong()) + varintField(2, bits.toLong()) + varintField(3, channels.toLong())
+
+    /** Service { id = 1; media_sink_service = 3 } carrying an audio sink. */
+    private fun audioSink(id: Int, codec: Int, audioType: Int, config: ByteArray) =
+        lenField(
+            1,
+            varintField(1, id.toLong()) +
+                lenField(3, varintField(1, codec.toLong()) + varintField(2, audioType.toLong()) + lenField(3, config)),
+        )
+
+    /** Channel 1: the H.264 video sink, which must not be mistaken for an audio one. */
+    private fun videoSink(): ByteArray {
+        val videoConfig = varintField(1, 2L) + varintField(2, 2L) + varintField(3, 0L) +
+            varintField(4, 12L) + varintField(5, 240L) + varintField(6, 0L) + varintField(8, 10_000L)
+        return lenField(
+            1,
+            varintField(1, 1L) + lenField(3, varintField(1, 3L) + lenField(4, videoConfig)),
+        )
+    }
+
+    /** Channel 3: the car's microphone, a media *source* (field 5), not a sink. */
+    private fun micSource(): ByteArray = lenField(
+        1,
+        varintField(1, 3L) + lenField(5, varintField(1, 1L) + lenField(2, audioConfig(16_000, 16, 1))),
+    )
+
+    private fun uconnectResponse(): ByteArray =
+        videoSink() +
+            micSource() +
+            audioSink(id = 5, codec = 1, audioType = 3, config = audioConfig(48_000, 16, 2)) +
+            audioSink(id = 6, codec = 1, audioType = 1, config = audioConfig(16_000, 16, 1)) +
+            Protobuf.stringField(2, "Uconnect") +
+            Protobuf.stringField(3, "Dodge Challenger") +
+            Protobuf.stringField(4, "18")
+
+    @Test
+    fun `finds both of the car's audio sinks and neither the video sink nor the microphone`() {
+        val sinks = ServiceDiscovery.findAudioServices(uconnectResponse())
+
+        assertEquals(listOf(5, 6), sinks.map { it.serviceId })
+        assertEquals(listOf("MEDIA", "GUIDANCE"), sinks.map { it.streamName })
+    }
+
+    @Test
+    fun `the media sink is PCM at 48kHz stereo`() {
+        val media = ServiceDiscovery.findAudioServices(uconnectResponse()).first { it.streamType == 3 }
+
+        assertEquals("AUDIO_PCM", media.codecName)
+        assertEquals(1, media.configs.size)
+        assertEquals(48_000, media.configs[0].sampleRate)
+        assertEquals(16, media.configs[0].bits)
+        assertEquals(2, media.configs[0].channels)
+    }
+
+    @Test
+    fun `the guidance sink is mono at 16kHz, so it must not be used for music`() {
+        val guidance = ServiceDiscovery.findAudioServices(uconnectResponse()).first { it.streamType == 1 }
+
+        assertEquals(16_000, guidance.configs[0].sampleRate)
+        assertEquals(1, guidance.configs[0].channels)
+    }
+
+    @Test
+    fun `the video sink is still found alongside the audio ones`() {
+        assertNotNull(ServiceDiscovery.findVideoService(uconnectResponse()))
+        assertEquals(1, ServiceDiscovery.findVideoService(uconnectResponse())!!.serviceId)
+    }
+}

settings.gradle.kts

@@ -25,4 +25,5 @@ dependencyResolutionManagement {
 
 rootProject.name = "Gearslip"
 include(":gearslip")
+// include(":ksdump")