playback: fix headset focus autoplay issue

Fix an issue where headset focus would result in unexpected playback
whenever the service started.

AudioManager.ACTION_HEADSET_PLUG seems to always fire when the initial
BroadcastReceiver is set up, which results in a weird bug where if a
wired headset is connected while PlaybackService is started, playback
will start immediately, which was not user friendly.

I fear that this may result in an edge case that results in headset
focus not firing in an unrelated situation, which in that case I would
be forced to remove headset autoplay entirely (or at least relegate it
to a quirk option).

CHANGELOG.md

@@ -15,6 +15,7 @@ from the system theme was used [#80]
 - Fixed music loading failure that would occur when certain paths were parsed [#84]
 - Fixed incorrect track numbers when the tag was formatted as NN/TT [#88]
 - Fixed years deliberately set as "0" showing up as "No Date"
+- Fixed headset management unexpectedly starting audio when the app initially opens
 
 #### What's Changed
 - All cover art is now cropped to a 1:1 aspect ratio

app/src/main/java/org/oxycblt/auxio/AuxioApp.kt

@@ -29,6 +29,10 @@ import org.oxycblt.auxio.coil.GenreImageFetcher
 import org.oxycblt.auxio.coil.MusicKeyer
 import org.oxycblt.auxio.settings.SettingsManager
 
+/**
+ * TODO: Phase out databinding
+ * TODO: Rework sealed classes to minimize whens and maximize overrides
+ */
 @Suppress("UNUSED")
 class AuxioApp : Application(), ImageLoaderFactory {
     override fun onCreate() {

app/src/main/java/org/oxycblt/auxio/MainActivity.kt

@@ -43,7 +43,6 @@ import org.oxycblt.auxio.util.systemBarInsetsCompat
  * TODO: Add a new view for crashes with a stack trace
  * TODO: Custom language support
  * TODO: Rework menus [perhaps add multi-select]
- * TODO: Phase out databinding
  */
 class MainActivity : AppCompatActivity() {
     private val playbackModel: PlaybackViewModel by viewModels()

app/src/main/java/org/oxycblt/auxio/home/HomeFragment.kt

@@ -56,6 +56,7 @@ import org.oxycblt.auxio.util.logTraceOrThrow
  * views for each respective item.
  * @author OxygenCobalt
  * TODO: Make tabs invisible when there is only one
+ * TODO: Add duration and song count sorts
  */
 class HomeFragment : Fragment() {
     private val playbackModel: PlaybackViewModel by activityViewModels()

app/src/main/java/org/oxycblt/auxio/music/Models.kt

@@ -149,7 +149,7 @@ data class Song(
  */
 data class Album(
     override val name: String,
-    /** The latest year of the songs in this album. */
+    /** The latest year of the songs in this album. Null if none of the songs had metadata. */
     val year: Int?,
     /** The URI for the cover art corresponding to this album. */
     val albumCoverUri: Uri,

app/src/main/java/org/oxycblt/auxio/music/MusicLoader.kt

@@ -241,6 +241,7 @@ class MusicLoader {
             // Use the song with the latest year as our metadata song.
             // This allows us to replicate the LAST_YEAR field, which is useful as it means that
             // weird years like "0" wont show up if there are alternatives.
+            // TODO: Weigh songs with null years lower than songs with zero years
             val templateSong = requireNotNull(
                 albumSongs.maxByOrNull { it.internalMediaStoreYear ?: 0 }
             )

app/src/main/java/org/oxycblt/auxio/music/MusicStore.kt

@@ -69,7 +69,8 @@ class MusicStore private constructor() {
             val start = System.currentTimeMillis()
 
             val loader = MusicLoader()
-            val library = loader.load(context) ?: return Response.Err(ErrorKind.NO_MUSIC)
+            val library = loader.load(context)
+                ?: return Response.Err(ErrorKind.NO_MUSIC)
 
             mSongs = library.songs
             mAlbums = library.albums
@@ -78,7 +79,7 @@ class MusicStore private constructor() {
 
             logD("Music load completed successfully in ${System.currentTimeMillis() - start}ms")
         } catch (e: Exception) {
-            logE("Something went horribly wrong")
+            logE("Music loading failed.")
             logE(e.stackTraceToString())
             return Response.Err(ErrorKind.FAILED)
         }

app/src/main/java/org/oxycblt/auxio/playback/system/PlaybackService.kt

@@ -439,7 +439,6 @@ class PlaybackService : Service(), Player.Listener, PlaybackStateManager.Callbac
     private fun stopForegroundAndNotification() {
         stopForeground(true)
         notificationManager.cancel(PlaybackNotification.NOTIFICATION_ID)
-
         isForeground = false
     }
 
@@ -448,6 +447,8 @@ class PlaybackService : Service(), Player.Listener, PlaybackStateManager.Callbac
      * TODO: Don't fire when the service initially starts?
      */
     private inner class PlaybackReceiver : BroadcastReceiver() {
+        private var handledInitialHeadsetPlug = false
+
         override fun onReceive(context: Context, intent: Intent) {
             when (intent.action) {
                 // --- SYSTEM EVENTS ---
@@ -461,12 +462,16 @@ class PlaybackService : Service(), Player.Listener, PlaybackStateManager.Callbac
                 AudioManager.ACTION_AUDIO_BECOMING_NOISY -> pauseFromPlug()
 
                 AudioManager.ACTION_HEADSET_PLUG -> {
+                    if (handledInitialHeadsetPlug) {
                         when (intent.getIntExtra("state", -1)) {
                             0 -> pauseFromPlug()
                             1 -> resumeFromPlug()
                         }
                     }
 
+                    handledInitialHeadsetPlug = true
+                }
+
                 // --- AUXIO EVENTS ---
                 ACTION_PLAY_PAUSE -> playbackManager.setPlaying(
                     !playbackManager.isPlaying