playlist: Give playlists a current_track property

This sets the current_trackid field on the database playlist object to
the trackid of the provided track.

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

emmental/playlist/playlist.py

@@ -54,6 +54,9 @@ class Playlist(model.TrackidModel):
     def on_trackid_removed(self, set: db.tracks.TrackidSet,
                            trackid: int) -> None:
         """Handle the TrackidSet::trackid-removed signal."""
+        if self.__playlist.current_trackid == trackid:
+            index = super().index(trackid) - 1
+            self.current_track = None if index < 0 else self[index]
         super().on_trackid_removed(set, trackid)
         self.__sort_keys.pop(trackid, None)
 
@@ -61,6 +64,8 @@ class Playlist(model.TrackidModel):
         """Handle the TrackidSet::trackids-reset signal."""
         self.__sort_keys.clear()
         super().on_trackids_reset(set)
+        if super().index(self.__playlist.current_trackid) is None:
+            self.current_track = None
 
     def add_track(self, track: db.tracks.Track) -> None:
         """Add a track to the playlist."""
@@ -91,6 +96,19 @@ class Playlist(model.TrackidModel):
         if self.__playlist is not None:
             self.__playlist.remove_track(track)
 
+    @GObject.Property(type=db.tracks.Track)
+    def current_track(self) -> db.tracks.Track | None:
+        """Get the current Track of the Playlist."""
+        if self.__playlist is not None:
+            return self.sql.tracks.rows.get(self.__playlist.current_trackid)
+
+    @current_track.setter
+    def current_track(self, track: db.tracks.Track | None) -> None:
+        """Set the current Track."""
+        if self.__playlist is not None:
+            trackid = 0 if track is None else track.trackid
+            self.__playlist.current_trackid = trackid
+
     @GObject.Property(type=db.playlist.Playlist)
     def playlist(self) -> db.playlist.Playlist | None:
         """Get the current db playlist."""
@@ -108,11 +126,16 @@ class Playlist(model.TrackidModel):
             self.__playlist.connect("notify", self.__playlist_notify)
             self.__sort_order = new.sort_order
             self.trackid_set = new.tracks
+
+            if len(self.trackids) > 0:
+                if new.current_trackid == self.trackids[-1]:
+                    new.current_trackid = 0
         else:
             self.__sort_order = None
             self.trackid_set = None
 
-        self.notify("sort-order")
+        for prop in ("current-track", "sort-order"):
+            self.notify(prop)
 
     @GObject.Property(type=str, flags=FLAGS)
     def sort_order(self) -> str:

tests/playlist/test_playlist.py

@@ -150,6 +150,79 @@ class TestPlaylist(tests.util.TestCase):
         self.playlist.remove_track(self.track1)
         self.assertListEqual(self.playlist.trackids, [])
 
+    def test_remove_current_track(self):
+        """Test removing the current-track from the playlist."""
+        self.db_plist.add_track(self.track1)
+        self.db_plist.add_track(self.track2)
+        self.db_plist.add_track(self.track3)
+        self.playlist.playlist = self.db_plist
+        self.playlist.current_track = self.track2
+
+        notify = unittest.mock.Mock()
+        self.playlist.connect("notify::current-track", notify)
+        self.playlist.remove_track(self.track3)
+        notify.assert_not_called()
+
+        self.playlist.remove_track(self.track2)
+        self.assertEqual(self.playlist.current_track, self.track1)
+        self.assertEqual(self.db_plist.current_trackid, self.track1.trackid)
+        notify.assert_called()
+
+        notify.reset_mock()
+        self.playlist.remove_track(self.track1)
+        self.assertIsNone(self.playlist.current_track)
+        self.assertEqual(self.db_plist.current_trackid, 0)
+        notify.assert_called()
+
+        self.playlist.add_track(self.track1)
+        self.playlist.add_track(self.track3)
+        self.playlist.current_track = self.track3
+
+        notify.reset_mock()
+        self.db_plist.remove_track(self.track3)
+        self.assertEqual(self.playlist.current_track, self.track1)
+        self.assertEqual(self.db_plist.current_trackid, self.track1.trackid)
+        notify.assert_called()
+
+    def test_current_track(self):
+        """Test the Playlist current-track property."""
+        self.assertIsNone(self.playlist.current_track)
+        self.playlist.current_track = self.track2
+        self.assertIsNone(self.playlist.current_track)
+
+        self.db_plist.add_track(self.track1)
+        self.db_plist.add_track(self.track2)
+        self.db_plist.add_track(self.track3)
+        self.db_plist.current_trackid = self.track2.trackid
+
+        notify = unittest.mock.Mock()
+        self.playlist.connect("notify::current-track", notify)
+        self.playlist.playlist = self.db_plist
+        self.assertEqual(self.playlist.current_track, self.track2)
+        notify.assert_called()
+
+        self.db_plist.current_trackid = self.track3.trackid
+        self.playlist.playlist = self.db_plist
+        self.assertEqual(self.db_plist.current_trackid, 0)
+        self.assertIsNone(self.playlist.current_track)
+
+        self.playlist.current_track = self.track1
+        self.assertEqual(self.db_plist.current_trackid, self.track1.trackid)
+        self.assertEqual(self.playlist.current_track, self.track1)
+
+        self.playlist.current_track = None
+        self.assertEqual(self.db_plist.current_trackid, 0)
+        self.assertIsNone(self.playlist.current_track)
+
+        self.db_plist.remove_track(self.track2)
+        self.db_plist.current_trackid = self.track2.trackid
+
+        notify.reset_mock()
+        self.db_plist.tracks.emit("trackids-reset")
+        self.assertEqual(self.db_plist.current_trackid, 0)
+        self.assertIsNone(self.playlist.current_track)
+        notify.assert_called()
+
     def test_playlist(self):
         """Test the playlist property."""
         self.assertIsNone(self.playlist.playlist)