feat: smart shuffle recommendation engine

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

@@ -51,6 +51,7 @@ import org.oxycblt.auxio.playback.ui.swiper.CarouselTransformer
 import org.oxycblt.auxio.playback.ui.swiper.CoverPagerAdapter
 import org.oxycblt.auxio.playback.ui.swiper.UserAwarePagerCallback
 import org.oxycblt.auxio.ui.ViewBindingFragment
+import org.oxycblt.auxio.util.collect
 import org.oxycblt.auxio.util.collectImmediately
 import org.oxycblt.auxio.util.dampen
 import org.oxycblt.auxio.util.recycler
@@ -166,6 +167,7 @@ class PlaybackPanelFragment :
         }
         binding.playbackSkipNext.setOnClickListener { playbackModel.next() }
         binding.playbackShuffle.setOnClickListener { playbackModel.toggleShuffled() }
+        binding.playbackLike.setOnClickListener { playbackModel.likeCurrentSong() }
         binding.playbackMore?.setOnClickListener {
             playbackModel.song.value?.let {
                 listModel.openMenu(R.menu.playback_song, it, PlaySong.ByItself)
@@ -179,7 +181,10 @@ class PlaybackPanelFragment :
         collectImmediately(playbackModel.repeatMode, ::updateRepeat)
         collectImmediately(playbackModel.isPlaying, ::updatePlaying)
         collectImmediately(playbackModel.isShuffled, ::updateShuffled)
+        collectImmediately(playbackModel.isLiked, ::updateLiked)
         collectImmediately(playbackModel.pagerQueue, ::updatePager)
+        collect(playbackModel.likedEvent.flow, ::handleLikedEvent)
+        collect(playbackModel.dislikedEvent.flow, ::handleDislikedEvent)
     }
 
     // FIXME: Old code!! Maybe not necessary anymore?
@@ -297,6 +302,25 @@ class PlaybackPanelFragment :
         requireBinding().playbackShuffle.isChecked = isShuffled
     }
 
+    private fun updateLiked(isLiked: Boolean) {
+        val likeButton = requireBinding().playbackLike
+        likeButton.isChecked = isLiked
+        likeButton.contentDescription =
+            getString(if (isLiked) R.string.desc_liked else R.string.desc_like)
+    }
+
+    private fun handleLikedEvent(event: Unit?) {
+        if (event == null) return
+        playbackModel.likedEvent.consume()
+        requireContext().showToast(R.string.lng_song_liked)
+    }
+
+    private fun handleDislikedEvent(event: Unit?) {
+        if (event == null) return
+        playbackModel.dislikedEvent.consume()
+        requireContext().showToast(R.string.lng_song_disliked)
+    }
+
     private fun updatePager(queue: PagerQueue) {
         // Right now there's easily 140ms of frame skipping when going next/prev. This is primarily
         // the fault of specifically the nested bottom sheet UI setup, which is intractable to

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

@@ -36,6 +36,8 @@ import org.oxycblt.auxio.playback.state.Progression
 import org.oxycblt.auxio.playback.state.QueueChange
 import org.oxycblt.auxio.playback.state.RepeatMode
 import org.oxycblt.auxio.playback.state.ShuffleMode
+import org.oxycblt.auxio.smartshuffle.SmartShuffle
+import org.oxycblt.auxio.smartshuffle.SmartShuffleTracker
 import org.oxycblt.auxio.util.Event
 import org.oxycblt.auxio.util.MutableEvent
 import org.oxycblt.musikr.Album
@@ -61,6 +63,8 @@ constructor(
     private val playbackSettings: PlaybackSettings,
     private val commandFactory: PlaybackCommand.Factory,
     private val listSettings: ListSettings,
+    private val smartShuffle: SmartShuffle,
+    private val smartShuffleTracker: SmartShuffleTracker,
 ) : ViewModel(), PlaybackStateManager.Listener, PlaybackSettings.Listener {
     private var lastPositionJob: Job? = null
 
@@ -77,6 +81,21 @@ constructor(
     val isPlaying: StateFlow<Boolean>
         get() = _isPlaying
 
+    private val _isLiked = MutableStateFlow(false)
+    /** Whether the current song was explicitly liked for Smart Shuffle. */
+    val isLiked: StateFlow<Boolean>
+        get() = _isLiked
+
+    private val _likedEvent = MutableEvent<Unit>()
+    /** One-shot event after the user likes the current song. */
+    val likedEvent: Event<Unit>
+        get() = _likedEvent
+
+    private val _dislikedEvent = MutableEvent<Unit>()
+    /** One-shot event after the user removes a like (explicit dislike). */
+    val dislikedEvent: Event<Unit>
+        get() = _dislikedEvent
+
     private val _positionDs = MutableStateFlow(0L)
     /** The current position, in deci-seconds (1/10th of a second). */
     val positionDs: StateFlow<Long>
@@ -131,6 +150,10 @@ constructor(
     init {
         playbackManager.addListener(this)
         playbackSettings.registerListener(this)
+        refreshPreferenceState()
+        viewModelScope.launch {
+            smartShuffle.preferenceRevision.collect { refreshPreferenceState() }
+        }
     }
 
     override fun onCleared() {
@@ -142,6 +165,7 @@ constructor(
         L.d("Index moved, updating current song")
         _positionDs.value = playbackManager.progression.calculateElapsedPositionMs().msToDs()
         _song.value = playbackManager.currentSong
+        refreshPreferenceState()
 
         _pagerCommand.put(PagerCommand(update = null, scroll = index))
         _pagerQueue.value = _pagerQueue.value.copy(index = index)
@@ -152,6 +176,7 @@ constructor(
         if (change.type == QueueChange.Type.SONG) {
             L.d("Queue changed, updating current song")
             _song.value = playbackManager.currentSong
+            refreshPreferenceState()
         }
 
         _pagerCommand.put(
@@ -181,6 +206,7 @@ constructor(
         _song.value = playbackManager.currentSong
         _parent.value = parent
         _isShuffled.value = isShuffled
+        refreshPreferenceState()
 
         _pagerCommand.put(PagerCommand(update = UpdateInstructions.Replace(0), scroll = index))
         _pagerQueue.value = PagerQueue(queue = queue, index = index)
@@ -623,6 +649,39 @@ constructor(
         playbackManager.shuffled(!playbackManager.isShuffled)
     }
 
+    /**
+     * Toggle preference for the current song.
+     *
+     * - Not liked → like (boost recommendations, clear undesirable)
+     * - Already liked → dislike (mark undesirable, skip to next)
+     */
+    fun likeCurrentSong() {
+        val song = playbackManager.currentSong
+        if (song == null) {
+            L.w("Cannot like/dislike without a current song")
+            return
+        }
+        if (smartShuffle.isLiked(song)) {
+            L.d("Already liked — disliking current song")
+            smartShuffle.dislike(song)
+            _isLiked.value = false
+            _dislikedEvent.put(Unit)
+            // Dislike already recorded preference; don't also count this as an early skip.
+            smartShuffleTracker.suppressFinish(song)
+            playbackManager.next()
+        } else {
+            L.d("Liking current song")
+            smartShuffle.like(song)
+            _isLiked.value = true
+            _likedEvent.put(Unit)
+        }
+    }
+
+    private fun refreshPreferenceState() {
+        val song = playbackManager.currentSong
+        _isLiked.value = song != null && smartShuffle.isLiked(song)
+    }
+
     /**
      * Toggle [repeatMode] (ex. from [RepeatMode.NONE] to [RepeatMode.TRACK])
      *

app/src/main/java/org/oxycblt/auxio/playback/service/BetterShuffleOrder.kt

@@ -125,6 +125,8 @@ class BetterShuffleOrder(private val shuffled: IntArray) : ShuffleOrder {
     }
 
     companion object {
+        fun identity(length: Int) = BetterShuffleOrder(IntArray(length) { it })
+
         private fun createShuffledList(length: Int, startIndex: Int): IntArray {
             val shuffled = IntArray(length)
             for (i in 0 until length) {

app/src/main/java/org/oxycblt/auxio/playback/service/ExoPlaybackStateHolder.kt

@@ -254,7 +254,13 @@ class ExoPlaybackStateHolder(
                 ?.let { command.queue.indexOf(it) }
                 .also { check(it != -1) { "Start song not in queue" } }
         if (command.shuffled) {
-            player.setShuffleOrder(BetterShuffleOrder(command.queue.size, startIndex ?: -1))
+            player.setShuffleOrder(
+                if (command.orderedShuffle) {
+                    BetterShuffleOrder.identity(command.queue.size)
+                } else {
+                    BetterShuffleOrder(command.queue.size, startIndex ?: -1)
+                }
+            )
         }
         val target = startIndex ?: player.currentTimeline.getFirstWindowIndex(command.shuffled)
         player.seekTo(target, C.TIME_UNSET)

app/src/main/java/org/oxycblt/auxio/playback/service/MediaSessionHolder.kt

@@ -46,6 +46,7 @@ import org.oxycblt.auxio.playback.state.PlaybackStateManager
 import org.oxycblt.auxio.playback.state.Progression
 import org.oxycblt.auxio.playback.state.QueueChange
 import org.oxycblt.auxio.playback.state.RepeatMode
+import org.oxycblt.auxio.smartshuffle.SmartShuffle
 import org.oxycblt.auxio.util.newBroadcastPendingIntent
 import org.oxycblt.auxio.util.newMainPendingIntent
 import org.oxycblt.musikr.MusicParent
@@ -66,6 +67,7 @@ private constructor(
     private val bitmapProvider: BitmapProvider,
     private val imageSettings: ImageSettings,
     private val mediaSessionInterface: MediaSessionInterface,
+    private val smartShuffle: SmartShuffle,
 ) : PlaybackStateManager.Listener, ImageSettings.Listener {
 
     class Factory
@@ -75,6 +77,7 @@ private constructor(
         private val bitmapProvider: BitmapProvider,
         private val imageSettings: ImageSettings,
         private val mediaSessionInterface: MediaSessionInterface,
+        private val smartShuffle: SmartShuffle,
     ) {
         fun create(context: Context, foregroundListener: ForegroundListener) =
             MediaSessionHolder(
@@ -84,6 +87,7 @@ private constructor(
                 bitmapProvider,
                 imageSettings,
                 mediaSessionInterface,
+                smartShuffle,
             )
     }
 
@@ -346,9 +350,32 @@ private constructor(
                 .build()
         state.addCustomAction(shuffleAction)
 
+        // Like toggle for Smart Shuffle (Android Auto + notification).
+        // Filled heart = liked; tapping again dislikes and skips.
+        val song = playbackManager.currentSong
+        val liked = song != null && smartShuffle.isLiked(song)
+        val likeAction =
+            PlaybackStateCompat.CustomAction.Builder(
+                    PlaybackActions.ACTION_LIKE,
+                    context.getString(
+                        if (liked) R.string.desc_liked else R.string.lbl_like
+                    ),
+                    if (liked) R.drawable.ic_heart_filled_24 else R.drawable.ic_heart_outline_24,
+                )
+                .build()
+        state.addCustomAction(likeAction)
+
         mediaSession.setPlaybackState(state.build())
     }
 
+    /** Refresh session/notification after an explicit like from Android Auto or UI. */
+    fun refreshAfterLike() {
+        invalidateSessionState()
+        if (!bitmapProvider.isBusy) {
+            foregroundListener.updateForeground(ForegroundListener.Change.MEDIA_SESSION)
+        }
+    }
+
     /** Invalidate both repeat and shuffle notification actions. */
     private fun invalidateNotificationActions() {
         L.d("Invalidating notification actions")

app/src/main/java/org/oxycblt/auxio/playback/service/PlaybackActions.kt

@@ -23,6 +23,7 @@ import org.oxycblt.auxio.BuildConfig
 object PlaybackActions {
     const val ACTION_INC_REPEAT_MODE = BuildConfig.APPLICATION_ID + ".action.LOOP"
     const val ACTION_INVERT_SHUFFLE = BuildConfig.APPLICATION_ID + ".action.SHUFFLE"
+    const val ACTION_LIKE = BuildConfig.APPLICATION_ID + ".action.LIKE"
     const val ACTION_SKIP_PREV = BuildConfig.APPLICATION_ID + ".action.PREV"
     const val ACTION_PLAY_PAUSE = BuildConfig.APPLICATION_ID + ".action.PLAY_PAUSE"
     const val ACTION_SKIP_NEXT = BuildConfig.APPLICATION_ID + ".action.NEXT"

app/src/main/java/org/oxycblt/auxio/playback/service/PlaybackServiceFragment.kt

@@ -35,6 +35,8 @@ import org.oxycblt.auxio.playback.PlaybackSettings
 import org.oxycblt.auxio.playback.state.DeferredPlayback
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
 import org.oxycblt.auxio.playback.state.Progression
+import org.oxycblt.auxio.smartshuffle.SmartShuffle
+import org.oxycblt.auxio.smartshuffle.SmartShuffleTracker
 import org.oxycblt.auxio.widgets.WidgetComponent
 import org.oxycblt.musikr.MusicParent
 import org.oxycblt.musikr.Song
@@ -50,6 +52,8 @@ private constructor(
     sessionHolderFactory: MediaSessionHolder.Factory,
     widgetComponentFactory: WidgetComponent.Factory,
     systemReceiverFactory: SystemPlaybackReceiver.Factory,
+    private val smartShuffleTracker: SmartShuffleTracker,
+    smartShuffle: SmartShuffle,
 ) : PlaybackStateManager.Listener {
     class Factory
     @Inject
@@ -60,6 +64,8 @@ private constructor(
         private val sessionHolderFactory: MediaSessionHolder.Factory,
         private val widgetComponentFactory: WidgetComponent.Factory,
         private val systemReceiverFactory: SystemPlaybackReceiver.Factory,
+        private val smartShuffleTracker: SmartShuffleTracker,
+        private val smartShuffle: SmartShuffle,
     ) {
         fun create(context: Context, foregroundListener: ForegroundListener) =
             PlaybackServiceFragment(
@@ -71,6 +77,8 @@ private constructor(
                 sessionHolderFactory,
                 widgetComponentFactory,
                 systemReceiverFactory,
+                smartShuffleTracker,
+                smartShuffle,
             )
     }
 
@@ -85,8 +93,16 @@ private constructor(
             context,
             widgetComponent,
             onExitRequested = { playbackManager.endSession() },
+            onLikeChanged = { sessionHolder.refreshAfterLike() },
         )
 
+    init {
+        // Keep Android Auto / notification like action in sync with mobile likes.
+        scope.launch {
+            smartShuffle.preferenceRevision.collect { sessionHolder.refreshAfterLike() }
+        }
+    }
+
     private fun scheduleAutoStop() {
         autoStopJob?.cancel()
         autoStopJob =
@@ -119,6 +135,7 @@ private constructor(
         sessionHolder.attach()
         widgetComponent.attach()
         systemReceiver.attach()
+        smartShuffleTracker.start()
         playbackManager.addListener(this)
         updateAutoStopTimer(playbackManager.progression.isPlaying)
         return sessionHolder.token
@@ -176,6 +193,7 @@ private constructor(
         autoStopJob?.cancel()
         waitJob.cancel()
         playbackManager.removeListener(this)
+        smartShuffleTracker.stop()
         systemReceiver.release()
         widgetComponent.release()
         sessionHolder.release()