 
     // MARK: Audio Player
 
-    var playingMessage: Message?
-    var playingFeedAudio: FeedAudio?
+    enum PlayingItem {
+        case MessageType(Message)
+        case FeedAudioType(FeedAudio)
+    }
+    var playingItem: PlayingItem?
+
+    var playingMessage: Message? {
+        guard let playingItem = playingItem else { return nil }
+
+        if case .MessageType(let message) = playingItem {
+            return message
+        }
+
+        return nil
+    }
+    var playingFeedAudio: FeedAudio? {
+        guard let playingItem = playingItem else { return nil }
+
+        if case .FeedAudioType(let feedAUdio) = playingItem {
+            return feedAUdio
+        }
+
+        return nil
+    }
 
     var playbackTimer: NSTimer? {
         didSet {

                    if audioPlayer.play() {
                        println("do play audio")

                        playingMessage = message

                        UIDevice.currentDevice().proximityMonitoringEnabled = true


                    if audioPlayer.play() {
                        println("do play audio")

                        playingItem = .FeedAudioType(feedAudio)

                        success()
                    }
