Media browser interface to show playlists on Android Auto

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserConnector.java

@@ -2,37 +2,60 @@ package org.schabi.newpipe.player.mediabrowser;
 
 import static org.schabi.newpipe.MainActivity.DEBUG;
 
+import android.net.Uri;
 import android.os.Bundle;
-import android.support.v4.media.MediaBrowserCompat;
+import android.os.ResultReceiver;
 import android.support.v4.media.MediaBrowserCompat.MediaItem;
+import android.support.v4.media.MediaDescriptionCompat;
 import android.support.v4.media.session.MediaSessionCompat;
+import android.support.v4.media.session.PlaybackStateCompat;
 import android.util.Log;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.StringRes;
 import androidx.media.MediaBrowserServiceCompat;
+import androidx.media.utils.MediaConstants;
 
+import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.ext.mediasession.MediaSessionConnector;
 
+import org.schabi.newpipe.NewPipeDatabase;
+import org.schabi.newpipe.R;
+import org.schabi.newpipe.database.AppDatabase;
+import org.schabi.newpipe.database.playlist.PlaylistMetadataEntry;
+import org.schabi.newpipe.database.playlist.PlaylistStreamEntry;
+import org.schabi.newpipe.local.playlist.LocalPlaylistManager;
 import org.schabi.newpipe.player.PlayerService;
+import org.schabi.newpipe.player.playqueue.PlayQueue;
+import org.schabi.newpipe.player.playqueue.SinglePlayQueue;
+import org.schabi.newpipe.util.NavigationHelper;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
+import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers;
 import io.reactivex.rxjava3.core.Single;
+import io.reactivex.rxjava3.disposables.Disposable;
 
-public class MediaBrowserConnector {
+public class MediaBrowserConnector implements MediaSessionConnector.PlaybackPreparer {
     private static final String TAG = MediaBrowserConnector.class.getSimpleName();
 
     private final PlayerService playerService;
     private final @NonNull MediaSessionConnector sessionConnector;
     private final @NonNull MediaSessionCompat mediaSession;
 
+    private AppDatabase database;
+    private LocalPlaylistManager localPlaylistManager;
+    private Disposable prepareOrPlayDisposable;
+
     public MediaBrowserConnector(@NonNull final PlayerService playerService) {
         this.playerService = playerService;
         mediaSession = new MediaSessionCompat(playerService, TAG);
         sessionConnector = new MediaSessionConnector(mediaSession);
         sessionConnector.setMetadataDeduplicationEnabled(true);
+        sessionConnector.setPlaybackPreparer(this);
         playerService.setSessionToken(mediaSession.getSessionToken());
     }
 
@@ -41,11 +64,58 @@ public class MediaBrowserConnector {
     }
 
     public void release() {
+        disposePrepareOrPlayCommands();
         mediaSession.release();
     }
 
     @NonNull
-    private static final String MY_MEDIA_ROOT_ID = "media_root_id";
+    private static final String ID_ROOT = "//${BuildConfig.APPLICATION_ID}/r";
+    @NonNull
+    private static final String ID_BOOKMARKS = ID_ROOT + "/playlists";
+
+    private MediaItem createRootMediaItem(final String mediaId, final String folderName) {
+        final var builder = new MediaDescriptionCompat.Builder();
+        builder.setMediaId(mediaId);
+        builder.setTitle(folderName);
+
+        final var extras = new Bundle();
+        extras.putString(MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_GROUP_TITLE,
+                playerService.getString(R.string.app_name));
+        builder.setExtras(extras);
+        return new MediaItem(builder.build(), MediaItem.FLAG_BROWSABLE);
+    }
+
+    private MediaItem createPlaylistMediaItem(final PlaylistMetadataEntry playlist) {
+        final var builder = new MediaDescriptionCompat.Builder();
+        builder.setMediaId(createMediaIdForPlaylist(playlist.getUid()))
+            .setTitle(playlist.name)
+            .setIconUri(Uri.parse(playlist.thumbnailUrl));
+
+        final var extras = new Bundle();
+        extras.putString(MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_GROUP_TITLE,
+                playerService.getResources().getString(R.string.tab_bookmarks));
+        builder.setExtras(extras);
+        return new MediaItem(builder.build(), MediaItem.FLAG_BROWSABLE);
+    }
+
+    private String createMediaIdForPlaylist(final long playlistId) {
+        return ID_BOOKMARKS + '/' + playlistId;
+    }
+
+    private MediaItem createPlaylistStreamMediaItem(final long playlistId,
+                                                    final PlaylistStreamEntry item,
+                                                    final int index) {
+        final var builder = new MediaDescriptionCompat.Builder();
+        builder.setMediaId(createMediaIdForPlaylistIndex(playlistId, index))
+                .setTitle(item.getStreamEntity().getTitle())
+                .setIconUri(Uri.parse(item.getStreamEntity().getThumbnailUrl()));
+
+         return new MediaItem(builder.build(), MediaItem.FLAG_PLAYABLE);
+    }
+
+    private String createMediaIdForPlaylistIndex(final long playlistId, final int index) {
+        return createMediaIdForPlaylist(playlistId) + '/' + index;
+    }
 
     @Nullable
     public MediaBrowserServiceCompat.BrowserRoot onGetRoot(@NonNull final String clientPackageName,
@@ -56,7 +126,7 @@ public class MediaBrowserConnector {
                   clientPackageName, clientUid, rootHints));
         }
 
-        return new MediaBrowserServiceCompat.BrowserRoot(MY_MEDIA_ROOT_ID, null);
+        return new MediaBrowserServiceCompat.BrowserRoot(ID_ROOT, null);
     }
 
     public Single<List<MediaItem>> onLoadChildren(@NonNull final String parentId) {
@@ -64,8 +134,145 @@ public class MediaBrowserConnector {
             Log.d(TAG, String.format("MediaBrowserService.onLoadChildren(%s)", parentId));
         }
 
-        final List<MediaBrowserCompat.MediaItem> mediaItems = new ArrayList<>();
+        final List<MediaItem> mediaItems = new ArrayList<>();
+        final var parentIdUri = Uri.parse(parentId);
 
+        if (parentId.equals(ID_ROOT)) {
+            mediaItems.add(
+                    createRootMediaItem(ID_BOOKMARKS,
+                            playerService.getResources().getString(R.string.tab_bookmarks)));
+
+        } else if (parentId.startsWith(ID_BOOKMARKS)) {
+            final var path = parentIdUri.getPathSegments();
+            if (path.size() == 2) {
+                return populateBookmarks();
+            } else if (path.size() == 3) {
+                final var playlistId = Long.parseLong(path.get(2));
+                return populatePlaylist(playlistId);
+            } else {
+                Log.w(TAG, "Unknown playlist uri " + parentId);
+            }
+        }
         return Single.just(mediaItems);
     }
+
+    private LocalPlaylistManager getPlaylistManager() {
+        if (database == null) {
+            database = NewPipeDatabase.getInstance(playerService);
+        }
+        if (localPlaylistManager == null) {
+            localPlaylistManager = new LocalPlaylistManager(database);
+        }
+        return localPlaylistManager;
+    }
+
+    private Single<List<MediaItem>> populateBookmarks() {
+        final var playlists = getPlaylistManager().getPlaylists().firstOrError();
+        return playlists.map(playlist ->
+                playlist.stream().map(this::createPlaylistMediaItem).collect(Collectors.toList()));
+    }
+
+    private Single<List<MediaItem>> populatePlaylist(final long playlistId) {
+        final var playlist = getPlaylistManager().getPlaylistStreams(playlistId).firstOrError();
+        return playlist.map(items -> {
+            final List<MediaItem> results = new ArrayList<>();
+            int index = 0;
+            for (final var item : items) {
+                results.add(createPlaylistStreamMediaItem(playlistId, item, index));
+                ++index;
+            }
+            return results;
+        });
+    }
+
+    private void playbackError(@StringRes final int resId, final int code) {
+        playerService.stopForImmediateReusing();
+        sessionConnector.setCustomErrorMessage(playerService.getString(resId), code);
+    }
+
+    private Single<PlayQueue> extractPlayQueueFromMediaId(final String mediaId) {
+        final Uri mediaIdUri = Uri.parse(mediaId);
+        if (mediaIdUri == null) {
+            return Single.error(new NullPointerException());
+        }
+        if (mediaId.startsWith(ID_BOOKMARKS)) {
+            final var path = mediaIdUri.getPathSegments();
+            if (path.size() == 4) {
+                final long playlistId = Long.parseLong(path.get(2));
+                final int index = Integer.parseInt(path.get(3));
+
+                return getPlaylistManager()
+                        .getPlaylistStreams(playlistId)
+                        .firstOrError()
+                        .map(items -> {
+                            final var infoItems = items.stream()
+                                    .map(PlaylistStreamEntry::toStreamInfoItem)
+                                    .collect(Collectors.toList());
+                            return new SinglePlayQueue(infoItems, index);
+                        });
+            }
+        }
+
+        return Single.error(new NullPointerException());
+    }
+
+    @Override
+    public long getSupportedPrepareActions() {
+        return PlaybackStateCompat.ACTION_PLAY_FROM_MEDIA_ID;
+    }
+
+    private void disposePrepareOrPlayCommands() {
+        if (prepareOrPlayDisposable != null) {
+            prepareOrPlayDisposable.dispose();
+            prepareOrPlayDisposable = null;
+        }
+    }
+
+    @Override
+    public void onPrepare(final boolean playWhenReady) {
+        disposePrepareOrPlayCommands();
+        // No need to prepare
+    }
+
+    @Override
+    public void onPrepareFromMediaId(@NonNull final String mediaId, final boolean playWhenReady,
+                                     @Nullable final Bundle extras) {
+        if (DEBUG) {
+            Log.d(TAG, String.format("MediaBrowserConnector.onPrepareFromMediaId(%s, %s, %s)",
+                  mediaId, playWhenReady, extras));
+        }
+
+        disposePrepareOrPlayCommands();
+        prepareOrPlayDisposable = extractPlayQueueFromMediaId(mediaId)
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe(
+                    playQueue -> {
+                        sessionConnector.setCustomErrorMessage(null);
+                        NavigationHelper.playOnBackgroundPlayer(playerService, playQueue,
+                                playWhenReady);
+                    },
+                    throwable -> playbackError(R.string.error_http_not_found,
+                            PlaybackStateCompat.ERROR_CODE_NOT_SUPPORTED)
+                );
+    }
+
+    @Override
+    public void onPrepareFromSearch(@NonNull final String query, final boolean playWhenReady,
+                                    @Nullable final Bundle extras) {
+        disposePrepareOrPlayCommands();
+        playbackError(R.string.content_not_supported, PlaybackStateCompat.ERROR_CODE_NOT_SUPPORTED);
+    }
+
+    @Override
+    public void onPrepareFromUri(@NonNull final Uri uri, final boolean playWhenReady,
+                                 @Nullable final Bundle extras) {
+        disposePrepareOrPlayCommands();
+        playbackError(R.string.content_not_supported, PlaybackStateCompat.ERROR_CODE_NOT_SUPPORTED);
+    }
+
+    @Override
+    public boolean onCommand(@NonNull final Player player, @NonNull final String command,
+                             @Nullable final Bundle extras, @Nullable final ResultReceiver cb) {
+        return false;
+    }
 }