Bringing more consistency in music.mpd.js regardless of the backend

platypush/backend/http/static/js/music.mpd.js

@@ -4,8 +4,8 @@ $(document).ready(function() {
         curPath = [],
         curTrackUpdateHandler,
         curTrackElapsed = {
-            timestamp: null,
-            elapsed: null,
+            timestamp: undefined,
+            elapsed: undefined,
         },
 
         $musicSearchForm = $('#music-search-form'),
@@ -125,6 +125,10 @@ $(document).ready(function() {
                         $('#seek-time-length').text(length ? timeToStr(length) : '-:--');
 
                         seekInterval = setInterval(function() {
+                            if (curTrackElapsed.elapsed === undefined) {
+                                return;
+                            }
+
                             var length = parseInt($trackSeeker.attr('max'));
                             var value = parseInt((new Date().getTime() - curTrackElapsed.timestamp)/1000)
                                 + curTrackElapsed.elapsed;
@@ -169,7 +173,7 @@ $(document).ready(function() {
             var updatePlayingTrack = function(track) {
                 return function() {
                     var $curTrack = $playlistContent.find('.playlist-track').filter(
-                        function() { return $(this).data('pos') == track.pos });
+                        function() { return $(this).data('file') === track.file });
 
                     if ($curTrack.length === 0) {
                         return;

platypush/backend/http/static/js/widgets/music.js

@@ -105,20 +105,26 @@ $(document).ready(function() {
     };
 
     var refreshStatus = function(status) {
+        if (!status) {
+            return;
+        }
+
         if ('state' in status) {
             setState(state=status.state);
         }
 
         if ('elapsed' in status) {
             setTrackElapsed(status.elapsed);
-        }
-
-        if ('position' in status) {
+        } else if ('position' in status) {
             setTrackElapsed(status.position);
         }
     };
 
     var refreshTrack = function(track) {
+        if (!track) {
+            return;
+        }
+
         if ('time' in track) {
             setTrackTime(track.time);
         }

platypush/backend/music/mopidy.py

@@ -143,6 +143,10 @@ class MusicMopidyBackend(Backend):
                 track = self._parse_track(track)
                 if not track:
                     return
+
+                status['state'] = 'play'
+                status['position'] = 0.0
+                status['time'] = track.get('time')
                 self.bus.post(NewPlayingTrackEvent(status=status, track=track))
             elif event == 'stream_title_changed':
                 m = re.match('^\s*(.+?)\s+-\s+(.*)\s*$', msg.get('title', ''))
@@ -151,7 +155,8 @@ class MusicMopidyBackend(Backend):
 
                 track['artist'] = m.group(1)
                 track['title'] = m.group(2)
-                track['position'] = 0.0
+                status['state'] = 'play'
+                status['position'] = 0.0
                 self.bus.post(NewPlayingTrackEvent(status=status, track=track))
             elif event == 'volume_changed':
                 status['volume'] = msg.get('volume')