Music started again after the car left is paused again

Deezer sometimes carried on out of the phone's speaker after the car was turned off. Apps that
are buffering are paused too, and two seconds later any that started by themselves are paused
again.

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

@@ -31,6 +31,11 @@ object CarServices {
 
     private var context: Context? = null
 
+    /** Buffering counts as playing: an app between songs is about to make sound again. */
+    private val PLAYING_STATES = setOf(PlaybackState.STATE_PLAYING, PlaybackState.STATE_BUFFERING)
+    /** How long after pausing for the car leaving to look again for an app that started by itself. */
+    private const val REPAUSE_MS = 2_000L
+
     val nav: CarAppConnection by lazy { CarAppConnection(requireNotNull(context)) }
     val media: CarMedia by lazy { CarMedia(requireNotNull(context)) }
 
@@ -253,11 +258,22 @@ object CarServices {
      * the phone's speaker. Unplugging a USB accessory isn't "audio becoming noisy" the way
      * headphones are, so the apps won't pause themselves. Every playing session is paused, not
      * just the one Gearslip opened: anything the car was playing was going through the car.
+     * An app can start again on its own once the speaker is given back a moment later, which a
+     * Deezer driver heard after turning the car off (issue #39), so the ones it paused are
+     * looked at once more and paused again if they're playing.
      */
     fun pausePhoneMedia(why: String = "the car left") {
         pausedForNow = null
         pausedOwnForNow = false
-        pause(why)
+        val paused = pause(why)
+        if (paused.isEmpty()) return
+        android.os.Handler(android.os.Looper.getMainLooper()).postDelayed({
+            val again = paused.filter { it.playbackState?.state in PLAYING_STATES }
+            again.forEach { runCatching { it.transportControls.pause() } }
+            if (again.isNotEmpty()) {
+                app.seb3thehacker.gearslip.GearslipLog.i("media: paused ${again.joinToString { it.packageName }} again: it started by itself after $why")
+            }
+        }, REPAUSE_MS)
     }
 
     /** What [pausePhoneMediaForNow] paused, for [resumePhoneMedia] to play again. */
@@ -293,7 +309,7 @@ object CarServices {
         val manager = ctx.getSystemService(MediaSessionManager::class.java)
         val listener = ComponentName(ctx, GearslipNotificationListener::class.java)
         val playing = try {
-            manager.getActiveSessions(listener).filter { it.playbackState?.state == PlaybackState.STATE_PLAYING }
+            manager.getActiveSessions(listener).filter { it.playbackState?.state in PLAYING_STATES }
         } catch (e: SecurityException) {
             null
         }