Status and track list suggested by @Jarbasal

This commit adds the status, extended track info as well as a tracklist
information as proposed by Jarbasal.

mycroft/skills/common_play_skill.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import re
-from enum import Enum
+from enum import Enum, IntEnum
 from abc import ABC, abstractmethod
 from mycroft.messagebus.message import Message
 from .mycroft_skill import MycroftSkill
@@ -29,6 +29,17 @@ class CPSMatchLevel(Enum):
     GENERIC = 6
 
 
+class CPSTrackStatus(IntEnum):
+    DISAMBIGUATION = 1  # not queued for playback, show in gui
+    PLAYING = 2  # Skill is handling playback internally
+    PLAYING_AUDIOSERVICE = 3  # Skill forwarded playback to audio service
+    QUEUED = 4  # Waiting playback to be handled inside skill
+    QUEUED_AUDIOSERVICE = 5  # Waiting playback in audio service
+    BUFFERING = 6  # Incase it's an online source the buffering state or
+    STALLED = 7  # stalled state helps to know when to show the buffering ui
+    END_OF_MEDIA = 8  # helps to know if we want to do autoplay or something
+
+
 class CommonPlaySkill(MycroftSkill, ABC):
     """ To integrate with the common play infrastructure of Mycroft
     skills should use this base class and override the two methods
@@ -168,6 +179,8 @@ class CommonPlaySkill(MycroftSkill, ABC):
         if 'utterance' not in kwargs:
             kwargs['utterance'] = self.play_service_string
         self.audioservice.play(*args, **kwargs)
+        self.CPS_send_status(uri=args[0],
+                             status=CPSTrackStatus.PLAYING_AUDIOSERVICE)
 
     def stop(self):
         """Stop anything playing on the audioservice."""
@@ -224,7 +237,9 @@ class CommonPlaySkill(MycroftSkill, ABC):
         pass
 
     def CPS_send_status(self, artist='', track='', album='', image='',
-                        **kwargs):
+                        uri='', track_length=None, elapsed_time=None,
+                        playlist_position=None,
+                        status=CPSTrackStatus.DISAMBIGUATION, **kwargs):
         """Inform system of playback status.
 
         If a skill is handling playback and wants the playback control to be
@@ -240,13 +255,35 @@ class CommonPlaySkill(MycroftSkill, ABC):
             track (str): Track name
             album (str): Album title
             image (str): url for image to show
+            uri (str): uri for track
+            track_length (float): track length in seconds
+            elapsed_time (float): current offset into track in seconds
+            playlist_postion (int):
         """
         data = {'skill': self.name,
+                'uri': uri,
                 'artist': artist,
-                'album': artist,
+                'album': album,
                 'track': track,
                 'image': image,
-                'status': None  # TODO Add status system
+                'track_length': track_length,
+                'elapsed_time': elapsed_time,
+                'playlist_position': playlist_position,
+                'status': status
                 }
         data = {**data, **kwargs}  # Merge extra arguments
         self.bus.emit(Message('play:status', data))
+
+    def CPS_send_tracklist(self, tracklist=None):
+        """Inform system of playlist track info.
+
+        Provides track data for playlist
+
+        Arguments:
+            tracklist (str/list): Tracklist data
+        """
+        tracklist = tracklist or []
+        if not isinstance(tracklist, list):
+            tracklist = [tracklist]
+        for idx, track in enumerate(tracklist):
+            self.CPS_send_status(playlist_position=idx, **track)