Add playback updates to PlaybackService

Add the ability for PlaybackService to move to the next song when the current one ends, update the duration, and also be played/paused.

app/src/main/java/org/oxycblt/auxio/detail/AlbumDetailFragment.kt

@@ -13,8 +13,8 @@ import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentAlbumDetailBinding
 import org.oxycblt.auxio.detail.adapters.DetailSongAdapter
 import org.oxycblt.auxio.music.MusicStore
-import org.oxycblt.auxio.playback.state.PlaybackMode
 import org.oxycblt.auxio.playback.PlaybackViewModel
+import org.oxycblt.auxio.playback.state.PlaybackMode
 import org.oxycblt.auxio.theme.applyDivider
 import org.oxycblt.auxio.theme.disable
 

app/src/main/java/org/oxycblt/auxio/library/LibraryFragment.kt

@@ -25,8 +25,8 @@ import org.oxycblt.auxio.music.BaseModel
 import org.oxycblt.auxio.music.Genre
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.playback.state.PlaybackMode
 import org.oxycblt.auxio.playback.PlaybackViewModel
+import org.oxycblt.auxio.playback.state.PlaybackMode
 import org.oxycblt.auxio.theme.applyColor
 import org.oxycblt.auxio.theme.applyDivider
 import org.oxycblt.auxio.theme.resolveAttr

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

@@ -8,6 +8,15 @@ import android.os.IBinder
 import com.google.android.exoplayer2.MediaItem
 import com.google.android.exoplayer2.Player
 import com.google.android.exoplayer2.SimpleExoPlayer
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.conflate
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.takeWhile
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.music.toURI
 import org.oxycblt.auxio.playback.state.PlaybackStateCallback
@@ -26,6 +35,11 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateCallback {
     private val mBinder = LocalBinder()
     private val playbackManager = PlaybackStateManager.getInstance()
 
+    private val serviceJob = Job()
+    private val serviceScope = CoroutineScope(
+        serviceJob + Dispatchers.Main
+    )
+
     override fun onBind(intent: Intent): IBinder {
         return mBinder
     }
@@ -41,17 +55,59 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateCallback {
 
         player.release()
         playbackManager.removeCallback(this)
+        serviceJob.cancel()
     }
 
     override fun onSongUpdate(song: Song?) {
-        song?.let {
-            val item = MediaItem.fromUri(it.id.toURI())
+        song?.let { song ->
+            val item = MediaItem.fromUri(song.id.toURI())
             player.setMediaItem(item)
             player.prepare()
             player.play()
         }
     }
 
+    override fun onPlayingUpdate(isPlaying: Boolean) {
+        if (isPlaying) {
+            player.play()
+
+            startPollingPosition()
+        } else {
+            player.pause()
+        }
+    }
+
+    fun doSeek(position: Long) {
+        player.seekTo(position * 1000)
+    }
+
+    // Awful Hack to get position polling to work, as exoplayer does not provide any
+    // onPositionChanged callback for some inane reason.
+    // FIXME: Consider using exoplayer UI elements here, don't be surprised if this causes problems.
+
+    private fun pollCurrentPosition() = flow {
+        while (player.currentPosition <= player.duration) {
+            emit(player.currentPosition)
+            delay(500)
+        }
+    }.conflate()
+
+    private fun startPollingPosition() {
+        serviceScope.launch {
+            pollCurrentPosition().takeWhile { true }.collect {
+                playbackManager.setPosition(it / 1000)
+            }
+        }
+    }
+
+    override fun onPlaybackStateChanged(state: Int) {
+        if (state == Player.STATE_ENDED) {
+            playbackManager.skipNext()
+        } else if (state == Player.STATE_READY) {
+            startPollingPosition()
+        }
+    }
+
     inner class LocalBinder : Binder() {
         fun getService() = this@PlaybackService
     }

app/src/main/java/org/oxycblt/auxio/playback/PlaybackViewModel.kt

@@ -82,9 +82,7 @@ class PlaybackViewModel(private val context: Context) : ViewModel(), PlaybackSta
         playbackIntent = Intent(context, PlaybackService::class.java).also {
             context.bindService(it, connection, Context.BIND_AUTO_CREATE)
         }
-    }
 
-    init {
         playbackManager.addCallback(this)
     }
 
@@ -132,6 +130,8 @@ class PlaybackViewModel(private val context: Context) : ViewModel(), PlaybackSta
 
     fun updatePositionWithProgress(progress: Int) {
         playbackManager.setPosition(progress.toLong())
+
+        playbackService.doSeek(progress.toLong())
     }
 
     // --- QUEUE FUNCTIONS ---

app/src/main/java/org/oxycblt/auxio/songs/SongsFragment.kt

@@ -10,8 +10,8 @@ import androidx.fragment.app.activityViewModels
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentSongsBinding
 import org.oxycblt.auxio.music.MusicStore
-import org.oxycblt.auxio.playback.state.PlaybackMode
 import org.oxycblt.auxio.playback.PlaybackViewModel
+import org.oxycblt.auxio.playback.state.PlaybackMode
 import org.oxycblt.auxio.theme.applyDivider
 
 class SongsFragment : Fragment() {