car: say when the phone's location is off, ten seconds into a drive, with Don't show again and a setting to turn the warning off

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

@@ -5,6 +5,7 @@ import app.seb3thehacker.gearslip.audio.AudioLink
 import app.seb3thehacker.gearslip.audio.CarMic
 import app.seb3thehacker.gearslip.media.CarMediaStatus
 import app.seb3thehacker.gearslip.car.BluetoothAudioCheck
+import app.seb3thehacker.gearslip.car.LocationCheck
 import app.seb3thehacker.gearslip.car.CarBluetooth
 import app.seb3thehacker.gearslip.car.ClusterNav
 import app.seb3thehacker.gearslip.car.DirectionsVoice
@@ -167,6 +168,7 @@ class GearslipRunner(
         CarMic.current = null
         CarBluetooth.onCarDisconnected()
         BluetoothAudioCheck.onCarDisconnected()
+        LocationCheck.onCarDisconnected()
         mediaStatus?.stop()
         mediaStatus = null
         clusterNav?.stop()
@@ -1016,6 +1018,7 @@ class GearslipRunner(
                     projection.onSurfaceReady(surface, width, height, config.density)
                     SessionStatus.projecting()
                     BluetoothAudioCheck.onProjecting()
+                    LocationCheck.onProjecting()
                 }
             }.onFailure { e -> log.e("encoder start failed", e) }
         }

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

@@ -29,7 +29,8 @@ import androidx.compose.ui.unit.dp
 /**
  * Asks once per car whether to pair it over Bluetooth, then waits while the phone shows its
  * pairing dialog. See [CarBluetooth]. With no pairing to do, says when Bluetooth audio isn't
- * connected; see [BluetoothAudioCheck]. Unlike the call prompt, a tap outside the card does nothing:
+ * connected (see [BluetoothAudioCheck]), or else when the phone's location is off (see
+ * [LocationCheck]). Unlike the call prompt, a tap outside the card does nothing:
  * the driver picks Pair or Not now.
  */
 @Composable
@@ -41,12 +42,20 @@ internal fun BluetoothPairOverlay() {
             val missing by BluetoothAudioCheck.missing.collectAsState()
             val dismissed by BluetoothAudioCheck.carDismissed.collectAsState()
             val warn by CarSettings.bluetoothWarning.collectAsState()
+            val locationOff by LocationCheck.off.collectAsState()
+            val locationDismissed by LocationCheck.carDismissed.collectAsState()
             if (missing && bluetoothAudio && warn && !dismissed) PairCard(
                 title = "Bluetooth isn't connected",
                 body = "Music plays over Bluetooth, but your phone isn't connected to the car. " +
                     "Connect it from the car's Bluetooth menu or your phone's.",
                 secondary = "Don't show again" to BluetoothAudioCheck::neverAgain,
                 primary = "OK" to BluetoothAudioCheck::dismissOnCar,
+            ) else if (locationOff && !locationDismissed) PairCard(
+                title = "Location is off",
+                body = "Map apps can't show where you are or give directions. Turn on location " +
+                    "in your phone's quick settings when you're parked.",
+                secondary = "Don't show again" to LocationCheck::neverAgain,
+                primary = "OK" to LocationCheck::dismissOnCar,
             )
         }
         CarBluetooth.Prompt.ASK -> PairCard(

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

@@ -68,6 +68,7 @@ object CarServices {
         DirectionsVoice.init(appContext)
         CarBluetooth.init(appContext)
         BluetoothAudioCheck.init(appContext)
+        LocationCheck.init(appContext)
         CarKeys.init(appContext)
         VoiceReply.init(appContext)
         // Loaded now, while nothing's waiting on it, so the first reply isn't slower than the rest.

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

@@ -30,6 +30,7 @@ object CarSettings {
     private const val KEY_PIPE_AUDIO = "car_pipe_audio"
 private const val KEY_SPEAK_DIRECTIONS = "car_speak_directions"
 private const val KEY_BLUETOOTH_WARNING = "car_bluetooth_warning"
+private const val KEY_LOCATION_WARNING = "car_location_warning"
     private const val KEY_AUDIO_CHOICE_ASKED = "car_audio_choice_asked"
     private const val KEY_LAST_NAV = "car_last_nav"
     private const val KEY_LAST_MEDIA = "car_last_media"
@@ -62,6 +63,7 @@ private const val KEY_BLUETOOTH_WARNING = "car_bluetooth_warning"
     private val pipeAudioFlow = MutableStateFlow(true)
     private val speakDirectionsFlow = MutableStateFlow(true)
     private val bluetoothWarningFlow = MutableStateFlow(true)
+    private val locationWarningFlow = MutableStateFlow(true)
     private val lastNavFlow = MutableStateFlow<String?>(null)
     private val lastMediaFlow = MutableStateFlow<String?>(null)
     private val autoplayFlow = MutableStateFlow(false)
@@ -163,6 +165,9 @@ private const val KEY_BLUETOOTH_WARNING = "car_bluetooth_warning"
     /** With Bluetooth audio, warn when the phone isn't connected to the car; see BluetoothAudioCheck. */
     val bluetoothWarning: StateFlow<Boolean> = bluetoothWarningFlow
 
+    /** Warn on the car when the phone's location is off; see LocationCheck. */
+    val locationWarning: StateFlow<Boolean> = locationWarningFlow
+
     /**
      * Whether the driver has already been offered Bluetooth after turning down the capture
      * dialog. Offered once only: someone who chose to keep the USB route shouldn't be nagged.
@@ -223,6 +228,7 @@ private const val KEY_BLUETOOTH_WARNING = "car_bluetooth_warning"
         // own voice already reaches the car.
         speakDirectionsFlow.value = AppSettings.getString(app, KEY_SPEAK_DIRECTIONS, pipeAudioFlow.value.toString()) == "true"
         bluetoothWarningFlow.value = AppSettings.getString(app, KEY_BLUETOOTH_WARNING, "true") == "true"
+        locationWarningFlow.value = AppSettings.getString(app, KEY_LOCATION_WARNING, "true") == "true"
         nightFlow.value = runCatching {
             NightMode.valueOf(AppSettings.getString(app, KEY_NIGHT, NightMode.AUTO.name))
         }.getOrDefault(NightMode.AUTO)
@@ -304,6 +310,11 @@ private const val KEY_BLUETOOTH_WARNING = "car_bluetooth_warning"
         AppSettings.putString(app, KEY_BLUETOOTH_WARNING, on.toString())
     }
 
+    fun setLocationWarning(on: Boolean) {
+        locationWarningFlow.value = on
+        AppSettings.putString(app, KEY_LOCATION_WARNING, on.toString())
+    }
+
     fun setExperimentalFeaturesEnabled(on: Boolean) {
         experimentalFeaturesFlow.value = on
         AppSettings.putString(app, KEY_EXPERIMENTAL_FEATURES, on.toString())

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

@@ -55,6 +55,7 @@ fun CarSettingsScreen() {
     val pipeAudio by CarSettings.pipeAudio.collectAsState()
     val speakDirections by CarSettings.speakDirections.collectAsState()
     val bluetoothWarning by CarSettings.bluetoothWarning.collectAsState()
+    val locationWarning by CarSettings.locationWarning.collectAsState()
     val autoplay by CarSettings.autoplay.collectAsState()
     val playerTitle by CarSettings.playerTitle.collectAsState()
     val theme by CarSettings.appTheme.collectAsState()
@@ -145,6 +146,11 @@ fun CarSettingsScreen() {
                 bluetoothWarning,
             ) { CarSettings.setBluetoothWarning(it) }
         }
+        ChoiceRow(
+            "Warn when location is off",
+            listOf(false to "Off", true to "On"),
+            locationWarning,
+        ) { CarSettings.setLocationWarning(it) }
 
         ChoiceRow(
             "Spoken directions",

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

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