Android Auto: Add shuffle and play button for the playlist

Background:
- While testing the Android auto app, I missed a quick way to shuffle and play the playlist.
- This adds the support to shuffle and play the playlist from the Android Auto app.

Changes:
- The "Shuffle and play" button is added as the first item in the playlist view.
- The button is only displayed for playlists that are not empty to prevent confusion.

Author: HatakeKakashri

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserCommon.kt

@@ -17,6 +17,8 @@ internal const val ID_STREAM = "stream"
 internal const val ID_PLAYLIST = "playlist"
 internal const val ID_CHANNEL = "channel"
 
+internal const val ID_SHUFFLE = "ID_SHUFFLE"
+
 internal fun infoItemTypeToString(type: InfoType): String {
     return when (type) {
         InfoType.STREAM -> ID_STREAM

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserImpl.kt

@@ -257,6 +257,28 @@ class MediaBrowserImpl(
             .build().toString()
     }
 
+    private fun createShuffleAndPlayMediaItem(
+        isRemote: Boolean,
+        playlistId: Long
+    ): MediaBrowserCompat.MediaItem {
+        val resources = context.resources
+
+        val builder = MediaDescriptionCompat.Builder()
+            .setMediaId(createMediaIdForPlaylistShuffle(isRemote, playlistId))
+            .setTitle(resources.getString(R.string.shuffle_and_play))
+
+        builder.setIconUri(
+            Uri.Builder().scheme(ContentResolver.SCHEME_ANDROID_RESOURCE)
+                .authority(resources.getResourcePackageName(R.drawable.ic_shuffle))
+                .appendPath(resources.getResourceTypeName(R.drawable.ic_shuffle))
+                .appendPath(resources.getResourceEntryName(R.drawable.ic_shuffle)).build()
+        )
+
+        return MediaBrowserCompat.MediaItem(
+            builder.build(), MediaBrowserCompat.MediaItem.FLAG_PLAYABLE
+        )
+    }
+
     private fun createLocalPlaylistStreamMediaItem(
         playlistId: Long,
         item: PlaylistStreamEntry,
@@ -301,6 +323,15 @@ class MediaBrowserImpl(
             .build().toString()
     }
 
+    private fun createMediaIdForPlaylistShuffle(
+        isRemote: Boolean,
+        playlistId: Long,
+    ): String {
+        return buildLocalPlaylistItemMediaId(isRemote, playlistId)
+            .appendPath(ID_SHUFFLE)
+            .build().toString()
+    }
+
     private fun createMediaIdForInfoItem(item: InfoItem): String {
         return buildInfoItemMediaId(item).build().toString()
     }
@@ -346,7 +377,10 @@ class MediaBrowserImpl(
     private fun populateLocalPlaylist(playlistId: Long): Single<List<MediaBrowserCompat.MediaItem>> {
         val playlist = LocalPlaylistManager(database).getPlaylistStreams(playlistId).firstOrError()
         return playlist.map { items ->
-            items.mapIndexed { index, item ->
+            val quickActions = if (items.isEmpty()) emptyList() else listOf(
+                createShuffleAndPlayMediaItem(false, playlistId)
+            )
+            quickActions + items.mapIndexed { index, item ->
                 createLocalPlaylistStreamMediaItem(playlistId, item, index)
             }
         }
@@ -356,9 +390,12 @@ class MediaBrowserImpl(
         return RemotePlaylistManager(database).getPlaylist(playlistId).firstOrError()
             .flatMap { ExtractorHelper.getPlaylistInfo(it.serviceId, it.url, false) }
             .map {
+                val quickActions = if (it.relatedItems.isEmpty()) emptyList() else listOf(
+                    createShuffleAndPlayMediaItem(false, playlistId)
+                )
                 // ignore it.errors, i.e. ignore errors about specific items, since there would
                 // be no way to show the error properly in Android Auto anyway
-                it.relatedItems.mapIndexed { index, item ->
+                quickActions + it.relatedItems.mapIndexed { index, item ->
                     createRemotePlaylistStreamMediaItem(playlistId, item, index)
                 }
             }

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserPlaybackPreparer.kt

@@ -138,6 +138,17 @@ class MediaBrowserPlaybackPreparer(
             .map { info -> PlaylistPlayQueue(info, index) }
     }
 
+    private fun extractShufflePlayQueue(isRemote: Boolean, playlistId: Long): Single<PlayQueue> {
+        return if (isRemote) {
+            extractRemotePlayQueue(playlistId, 0)
+        } else {
+            extractLocalPlayQueue(playlistId, 0)
+        }.map { playQueue ->
+            playQueue.shuffle()
+            playQueue
+        }
+    }
+
     private fun extractPlayQueueFromMediaId(mediaId: String): Single<PlayQueue> {
         try {
             val mediaIdUri = mediaId.toUri()
@@ -184,6 +195,10 @@ class MediaBrowserPlaybackPreparer(
                     throw parseError(mediaId)
                 }
                 val playlistId = path[0].toLong()
+                if (ID_SHUFFLE == path[1]) {
+                    return extractShufflePlayQueue(playlistType == ID_REMOTE, playlistId)
+                }
+
                 val index = path[1].toInt()
                 return if (playlistType == ID_LOCAL)
                     extractLocalPlayQueue(playlistId, index)

app/src/main/res/values/strings.xml

@@ -666,6 +666,7 @@
     <string name="app_language_title">App language</string>
     <string name="systems_language">System default</string>
     <string name="remove_watched">Remove watched</string>
+    <string name="shuffle_and_play">Shuffle and play</string>
     <string name="remove_watched_popup_title">Remove watched videos?</string>
     <string name="remove_duplicates">Remove duplicates</string>
     <string name="remove_duplicates_title">Remove duplicates?</string>