feat(app): Implement tag handling modes according to #28.

If the tagmode setting is 'tagremains' (the default): Play as long as the
tag is on the reader, with a 5 second timeout (i.e. playback stops when
tag is gone for more than 5 seconds).

If the tagmode setting is 'tagstartstop': Playback starts when a tag is
seen. Presenting a different tag causes the playback to stop and
playback for the new tag to start. Re-presenting the same tag used to
start with a no-tag-time of 5 seconds or more in between stops playback.

Signed-off-by: Matthias Blankertz <matthias@blankertz.org>

software/src/app.py

@@ -44,6 +44,9 @@ class PlayerApp:
         self.player = deps.mp3player(self)
         self.nfc = deps.nfcreader(self.tag_state_machine)
         self.playlist_db = deps.playlistdb(self)
+        self.tag_mode = self.playlist_db.getSetting('tagmode')
+        self.playing_tag = None
+        self.playlist = None
         self.buttons = deps.buttons(self) if deps.buttons is not None else None
         self.mp3file = None
         self.volume_pos = 3
@@ -59,17 +62,21 @@ class PlayerApp:
         Callback (typically called by TagStateMachine) to signal that a new tag has been presented.
         """
         uid_str = b''.join('{:02x}'.format(x).encode() for x in new_tag)
-        self._set_playlist(uid_str)
+        if self.tag_mode == 'tagremains' or (self.tag_mode == 'tagstartstop' and new_tag != self.playing_tag):
+            self._set_playlist(uid_str)
+            self.playing_tag = new_tag
+        elif self.tag_mode == 'tagstartstop':
+            print('Tag presented again, stopping playback')
+            self._unset_playlist()
+            self.playing_tag = None
 
     def onTagRemoved(self):
         """
         Callback (typically called by TagStateMachine) to signal that a tag has been removed.
         """
-        print('Tag gone, stopping playback')
+        if self.tag_mode == 'tagremains':
-        if self.playlist is not None:
+            print('Tag gone, stopping playback')
-            pos = self.player.stop()
+            self._unset_playlist()
-            if pos is not None:
-                self.playlist.setPlaybackOffset(pos)
 
     def onButtonPressed(self, what):
         assert self.buttons is not None
@@ -89,10 +96,18 @@ class PlayerApp:
         self._play_next()
 
     def _set_playlist(self, tag: bytes):
+        self._unset_playlist()
         self.playlist = self.playlist_db.getPlaylistForTag(tag)
         self._play(self.playlist.getCurrentPath() if self.playlist is not None else None,
                    self.playlist.getPlaybackOffset() if self.playlist is not None else 0)
 
+    def _unset_playlist(self):
+        if self.playlist is not None:
+            pos = self.player.stop()
+            if pos is not None:
+                self.playlist.setPlaybackOffset(pos)
+            self.playlist = None
+
     def _play_next(self):
         if self.playlist is None:
             return
@@ -100,6 +115,7 @@ class PlayerApp:
         self._play(filename)
         if filename is None:
             self.playlist = None
+            self.playing_tag = None
 
     def _play(self, filename: bytes | None, offset=0):
         if self.mp3file is not None:

software/src/utils/playlistdb.py

@@ -31,6 +31,9 @@ class BTreeDB(IPlaylistDB):
     PERSIST_NO = b'no'
     PERSIST_TRACK = b'track'
     PERSIST_OFFSET = b'offset'
+    DEFAULT_SETTINGS = {
+        b'tagmode': b'tagremains'
+    }
 
     class Playlist(IPlaylist):
         def __init__(self, parent: "BTreeDB", tag: bytes, pos: int, persist, shuffle):
@@ -269,6 +272,11 @@ class BTreeDB(IPlaylistDB):
         self._savePlaylist(tag, entries, persist, shuffle)
         return self.getPlaylistForTag(tag)
 
+    def getSetting(self, key: bytes | str) -> str:
+        if key is str:
+            key = key.encode()
+        return self.db.get(b'settings/' + key, self.DEFAULT_SETTINGS[key]).decode()
+
     def validate(self, dump=False):
         """
         Validate the structure of the playlist database.
@@ -286,6 +294,11 @@ class BTreeDB(IPlaylistDB):
             fields = k.split(b'/')
             if len(fields) <= 1:
                 fail(f'Malformed key {k!r}')
+                continue
+            if fields[0] == b'settings':
+                val = self.db[k].decode()
+                print(f'Setting {fields[1].decode()} = {val}')
+                continue
             if last_tag != fields[0]:
                 last_tag = fields[0]
                 last_pos = None

software/tests/test_playerapp.py

@@ -38,11 +38,17 @@ class FakeMp3Player:
     def play(self, track: FakeFile, offset: int):
         self.track = track
 
+    def stop(self):
+        self.track = None
+
 
 class FakeTimerManager:
     def __init__(self): pass
     def cancel(self, timer): pass
 
+    def schedule(self, when, what):
+        what()
+
 
 class FakeNfcReader:
     tag_callback = None
@@ -79,6 +85,11 @@ class FakePlaylistDb:
     def getPlaylistForTag(self, tag: bytes):
         return self.FakePlaylist(self)
 
+    def getSetting(self, key: bytes | str):
+        if key == 'tagmode':
+            return 'tagremains'
+        return None
+
 
 def fake_open(filename, mode):
     return FakeFile(filename, mode)
@@ -106,7 +117,7 @@ def test_load_playlist_on_tag(micropythonify, faketimermanager, monkeypatch):
                             nfcreader=lambda x: FakeNfcReader(x),
                             buttons=lambda _: FakeButtons(),
                             playlistdb=lambda _: fake_db)
-    dut = app.PlayerApp(deps)
+    app.PlayerApp(deps)
     with monkeypatch.context() as m:
         m.setattr(builtins, 'open', fake_open)
         FakeNfcReader.tag_callback.onTagChange([23, 42, 1, 2, 3])
@@ -150,14 +161,88 @@ def test_playlist_unknown_tag(micropythonify, faketimermanager, monkeypatch):
         def getPlaylistForTag(self, tag):
             return None
 
+        def getSetting(self, key: bytes | str):
+            return None
+
     fake_db = FakeNoPlaylistDb()
     fake_mp3 = FakeMp3Player()
     deps = app.Dependencies(mp3player=lambda _: fake_mp3,
                             nfcreader=lambda x: FakeNfcReader(x),
                             buttons=lambda _: FakeButtons(),
                             playlistdb=lambda _: fake_db)
-    dut = app.PlayerApp(deps)
+    app.PlayerApp(deps)
     with monkeypatch.context() as m:
         m.setattr(builtins, 'open', fake_open)
         FakeNfcReader.tag_callback.onTagChange([23, 42, 1, 2, 3])
         assert fake_mp3.track is None
+
+
+def test_tagmode_startstop(micropythonify, faketimermanager, monkeypatch):
+    class MyFakePlaylistDb(FakePlaylistDb):
+        def __init__(self, tracklist=[b'test/path.mp3']):
+            super().__init__(tracklist)
+
+        def getSetting(self, key: bytes | str):
+            if key == 'tagmode':
+                return 'tagstartstop'
+            return None
+
+    fake_db = MyFakePlaylistDb()
+    fake_mp3 = FakeMp3Player()
+    deps = app.Dependencies(mp3player=lambda _: fake_mp3,
+                            nfcreader=lambda x: FakeNfcReader(x),
+                            buttons=lambda _: FakeButtons(),
+                            playlistdb=lambda _: fake_db)
+    app.PlayerApp(deps)
+    with monkeypatch.context() as m:
+        m.setattr(builtins, 'open', fake_open)
+        # Present tag to start playback
+        FakeNfcReader.tag_callback.onTagChange([23, 42, 1, 2, 3])
+        assert fake_mp3.track is not None
+        assert fake_mp3.track.filename == b'test/path.mp3'
+        # Removing tag should not stop playback
+        FakeNfcReader.tag_callback.onTagChange(None)
+        assert fake_mp3.track is not None
+        assert fake_mp3.track.filename == b'test/path.mp3'
+        # Presenting tag should stop playback
+        FakeNfcReader.tag_callback.onTagChange([23, 42, 1, 2, 3])
+        assert fake_mp3.track is None
+        # Nothing should change here
+        FakeNfcReader.tag_callback.onTagChange(None)
+        assert fake_mp3.track is None
+        # Presenting tag again should start playback again
+        FakeNfcReader.tag_callback.onTagChange([23, 42, 1, 2, 3])
+        assert fake_mp3.track is not None
+        assert fake_mp3.track.filename == b'test/path.mp3'
+
+
+def test_tagmode_remains(micropythonify, faketimermanager, monkeypatch):
+    class MyFakePlaylistDb(FakePlaylistDb):
+        def __init__(self, tracklist=[b'test/path.mp3']):
+            super().__init__(tracklist)
+
+        def getSetting(self, key: bytes | str):
+            if key == 'tagmode':
+                return 'tagremains'
+            return None
+
+    fake_db = MyFakePlaylistDb()
+    fake_mp3 = FakeMp3Player()
+    deps = app.Dependencies(mp3player=lambda _: fake_mp3,
+                            nfcreader=lambda x: FakeNfcReader(x),
+                            buttons=lambda _: FakeButtons(),
+                            playlistdb=lambda _: fake_db)
+    app.PlayerApp(deps)
+    with monkeypatch.context() as m:
+        m.setattr(builtins, 'open', fake_open)
+        # Present tag to start playback
+        FakeNfcReader.tag_callback.onTagChange([23, 42, 1, 2, 3])
+        assert fake_mp3.track is not None
+        assert fake_mp3.track.filename == b'test/path.mp3'
+        # Remove tag to stop playback
+        FakeNfcReader.tag_callback.onTagChange(None)
+        assert fake_mp3.track is None
+        # Presenting tag again should start playback again
+        FakeNfcReader.tag_callback.onTagChange([23, 42, 1, 2, 3])
+        assert fake_mp3.track is not None
+        assert fake_mp3.track.filename == b'test/path.mp3'