feat: expose player over MPRIS for system media controls

Register a session D-Bus MPRIS service (org.mpris.MediaPlayer2.mtsmusic)
in both the TUI and Qt apps, so the player shows up as a media source:
play/pause, next/previous, seek, metadata (title/artist/album/length/art)
and volume can be controlled from the GNOME media-controls extension,
playerctl and other MPRIS clients. Integration is optional and degrades
to a no-op without dbus-next or a session bus.

tui.py

@@ -43,6 +43,7 @@ from mtsmusic import (
     resolve_stream,
 )
 from player import MusicPlayer
+from mpris import MprisService, track_object_path
 from settings import (
     START_QUEUE_LABELS,
     START_QUEUES,
@@ -459,6 +460,52 @@ class MenuScreen(ModalScreen[str | None]):
 # ---------------------------------------------------------------------------
 
 
+class TuiMprisHandler:
+    """Прокидывает команды MPRIS из D-Bus в поток приложения Textual."""
+
+    def __init__(self, app: "MusicTui") -> None:
+        self.app = app
+
+    def _call(self, method: str, *args) -> None:
+        callback = getattr(self.app, method, None)
+        if callback is None:
+            return
+        try:
+            self.app.call_from_thread(callback, *args)
+        except Exception:
+            return
+
+    def on_play(self) -> None:
+        self._call("action_play_current")
+
+    def on_pause(self) -> None:
+        self._call("mpris_pause")
+
+    def on_play_pause(self) -> None:
+        self._call("action_toggle_pause")
+
+    def on_stop(self) -> None:
+        self._call("mpris_stop")
+
+    def on_next(self) -> None:
+        self._call("action_next_track")
+
+    def on_previous(self) -> None:
+        self._call("action_prev_track")
+
+    def on_seek(self, offset: int) -> None:
+        self._call("mpris_seek", offset)
+
+    def on_set_position(self, track_id: str, position: int) -> None:
+        self._call("mpris_set_position", track_id, position)
+
+    def on_volume(self, value: float) -> None:
+        self._call("mpris_set_volume", value)
+
+    def on_quit(self) -> None:
+        self._call("exit")
+
+
 class MusicTui(App):
     TITLE = "MTS Music"
 
@@ -585,6 +632,7 @@ class MusicTui(App):
         self.cover_bytes: dict[str, bytes] = {}
         self.cover_rendered: dict[tuple[str, int], Text] = {}
         self.cover_width = 40
+        self.mpris: MprisService | None = None
 
     # -- разметка ---------------------------------------------------------
 
@@ -615,6 +663,8 @@ class MusicTui(App):
         self.theme = "mono"
         self.set_interval(0.4, self.tick)
         self.apply_cover_width()
+        self.mpris = MprisService(TuiMprisHandler(self), identity="MTS Music")
+        self.mpris.update_volume(self.player.volume / 100)
         try:
             self.api = Api()
         except SystemExit:
@@ -627,6 +677,8 @@ class MusicTui(App):
         self.load_initial()
 
     async def on_unmount(self) -> None:
+        if self.mpris:
+            self.mpris.close()
         await self.player.stop()
 
     # -- геометрия --------------------------------------------------------
@@ -749,6 +801,7 @@ class MusicTui(App):
         self.update_like_button(liked)
         self.update_play_button()
         self.update_time()
+        self._update_mpris_metadata()
         self.sub_title = track.get("title") or ""
 
     def update_like_button(self, liked: bool | None = None) -> None:
@@ -761,6 +814,7 @@ class MusicTui(App):
 
     def update_play_button(self) -> None:
         self.query_one("#playpause", Button).label = "⏸" if self.player.paused else "▶"
+        self._update_mpris_status()
 
     def update_time(self) -> None:
         duration = (self.current or {}).get("durationMs") or 0
@@ -770,6 +824,8 @@ class MusicTui(App):
         self.query_one("#time", Static).update(
             f"{fmt_duration(int(elapsed * 1000))} / {fmt_duration(duration)}"
         )
+        if self.mpris:
+            self.mpris.update_position(int(elapsed * 1000) * 1000)
 
     # -- обложка ----------------------------------------------------------
 
@@ -1069,6 +1125,76 @@ class MusicTui(App):
         volume = int(self.settings.get("volume", 80))
         if self.player.volume != volume:
             self.run_worker(self.player.set_volume(volume), group="volume", exclusive=True)
+        if self.mpris:
+            self.mpris.update_volume(volume / 100)
+
+    # -- MPRIS ------------------------------------------------------------
+
+    def _update_mpris_status(self) -> None:
+        if not self.mpris:
+            return
+        if self.player.is_playing() and not self.player.paused:
+            status = "Playing"
+        elif self.player.is_playing():
+            status = "Paused"
+        else:
+            status = "Stopped"
+        self.mpris.update_playback_status(status)
+
+    def _update_mpris_metadata(self) -> None:
+        if not self.mpris:
+            return
+        track = self.current
+        if not track:
+            self.mpris.clear_metadata()
+            self.mpris.update_capabilities(
+                can_next=False, can_previous=False, can_seek=False
+            )
+            return
+        self.mpris.update_metadata(
+            track.get("id"),
+            title=str(track.get("title") or ""),
+            artist=track_artist(track),
+            album=track_album(track),
+            duration_ms=int(track.get("durationMs") or 0),
+            art_url=track_cover_url(track) or "",
+        )
+        has_queue = bool(self.queue or self.wave)
+        self.mpris.update_capabilities(
+            can_next=has_queue, can_previous=has_queue, can_seek=True
+        )
+
+    def mpris_pause(self) -> None:
+        if self.player.is_playing() and not self.player.paused:
+            self.player.toggle_pause()
+            self.update_play_button()
+
+    def mpris_stop(self) -> None:
+        self.run_worker(self._mpris_stop(), group="playback", exclusive=True)
+
+    async def _mpris_stop(self) -> None:
+        await self.player.stop()
+        self.update_play_button()
+        self.update_time()
+
+    def mpris_seek(self, offset_us: int) -> None:
+        if not self.current or not self.player.is_playing():
+            return
+        self.seek(offset_us / 1_000_000)
+
+    def mpris_set_position(self, track_path: str, position_us: int) -> None:
+        if not self.current or not self.player.is_playing():
+            return
+        if track_object_path(self.current.get("id")) != track_path:
+            return
+        duration = (self.current.get("durationMs") or 0) / 1000
+        target = max(0.0, position_us / 1_000_000)
+        if duration > 0:
+            target = min(target, duration - 1)
+        self.seek(target - self.player.elapsed())
+
+    def mpris_set_volume(self, value: float) -> None:
+        self.update_setting("volume", int(round(max(0.0, min(1.0, value)) * 100)))
 
     def action_show_favorites(self) -> None:
         self.push_screen(FavoritesScreen())