Implement initial mute action

app/src/main/java/org/jellyfin/androidtv/ui/playback/PlaybackControllerHelper.kt

@@ -45,10 +45,10 @@ fun PlaybackController.applyMediaSegments(
 
 			when (action) {
 				MediaSegmentAction.SKIP -> addSkipAction(mediaSegment)
+				MediaSegmentAction.MUTE -> addMuteAction(mediaSegment)
 
-				// TODO implement these
+				// TODO implement the UI
 				MediaSegmentAction.ASK_TO_SKIP -> TODO()
-				MediaSegmentAction.MUTE -> TODO()
 
 				MediaSegmentAction.NOTHING -> Unit
 			}
@@ -60,6 +60,9 @@ fun PlaybackController.applyMediaSegments(
 private fun PlaybackController.addSkipAction(mediaSegment: MediaSegmentDto) {
 	mVideoManager.mExoPlayer
 		.createMessage { messageType: Int, payload: Any? ->
+			// We can't seek directly on the ExoPlayer instance as not all media is seekable
+			// the seek function in the PlaybackController checks this and optionally starts a transcode
+			// at the requested position
 			fragment.lifecycleScope.launch(Dispatchers.Main) {
 				seek(mediaSegment.endTicks.ticks.inWholeMilliseconds)
 			}
@@ -69,3 +72,39 @@ private fun PlaybackController.addSkipAction(mediaSegment: MediaSegmentDto) {
 		.setDeleteAfterDelivery(false)
 		.send()
 }
+
+@OptIn(UnstableApi::class)
+private fun PlaybackController.addMuteAction(mediaSegment: MediaSegmentDto) {
+	// TODO: This action does not currently restore the volume if manually seeked over it
+	// as exoplayer only triggers a message event when the seekhead goes over its position naturally
+	// TODO: The action also does not enable the mute state when manually seeking into it
+	if (mediaSegment.endTicks <= mediaSegment.startTicks) return
+
+	var previousVolume: Float? = null
+
+	mVideoManager.mExoPlayer
+		.createMessage { messageType: Int, payload: Any? ->
+			fragment.lifecycleScope.launch(Dispatchers.Main) {
+				previousVolume = mVideoManager.mExoPlayer.volume
+				mVideoManager.mExoPlayer.volume = 0f
+			}
+		}
+		.setPosition(mediaSegment.startTicks.ticks.inWholeMilliseconds)
+		.setDeleteAfterDelivery(false)
+		.send()
+
+	mVideoManager.mExoPlayer
+		.createMessage { messageType: Int, payload: Any? ->
+			// Only restore if the volume is still muted and previousVolume is still set
+			fragment.lifecycleScope.launch(Dispatchers.Main) {
+				if (mVideoManager.mExoPlayer.volume == 0f) {
+					previousVolume?.let {
+						mVideoManager.mExoPlayer.volume = it
+					}
+				}
+			}
+		}
+		.setPosition(mediaSegment.endTicks.ticks.inWholeMilliseconds)
+		.setDeleteAfterDelivery(false)
+		.send()
+}