music-assistant-server

1"""Sync Group Player implementation."""
2
3from __future__ import annotations
4
5import asyncio
6import time
7from contextlib import asynccontextmanager
8from typing import TYPE_CHECKING, Any, cast
9
10from music_assistant_models.config_entries import ConfigEntry, ConfigValueOption
11from music_assistant_models.constants import PLAYER_CONTROL_FAKE
12from music_assistant_models.enums import ConfigEntryType, PlaybackState, PlayerFeature, PlayerType
13from music_assistant_models.errors import PlayerCommandFailed, UnsupportedFeaturedException
14from propcache import under_cached_property as cached_property
15
16from music_assistant.constants import (
17    APPLICATION_NAME,
18    CONF_DYNAMIC_GROUP_MEMBERS,
19    CONF_GROUP_MEMBERS,
20    CONF_POWER_CONTROL,
21)
22from music_assistant.controllers.players.constants import PlayerLockPurpose
23from music_assistant.models.player import DeviceInfo, Player, PlayerMedia
24
25from .constants import (
26    CONF_ALLOWED_MEMBERS,
27    CONF_ENTRY_SGP_NOTE,
28    EXTRA_FEATURES_FROM_MEMBERS,
29    IDLE_GRACE_SECONDS,
30    PLAYBACK_START_TIMEOUT,
31    PROVIDERS_WITH_DYNAMIC_LEADER_SWITCH,
32    REFORM_DEBOUNCE_SECONDS,
33)
34
35if TYPE_CHECKING:
36    from collections.abc import AsyncIterator
37
38    from music_assistant_models.player import PlayerSource
39
40    from .provider import SyncGroupProvider
41
42
43class SyncGroupPlayer(Player):
44    """Sync Group Player implementation."""
45
46    _attr_type: PlayerType = PlayerType.GROUP
47    sync_leader: Player | None = None
48    """The active sync leader player for this syncgroup."""
49
50    def __init__(
51        self,
52        provider: SyncGroupProvider,
53        player_id: str,
54    ) -> None:
55        """Initialize SyncGroupPlayer instance."""
56        super().__init__(provider, player_id)
57        self._attr_name = self.config.name or self.config.default_name or f"SyncGroup {player_id}"
58        self._attr_available = True
59        self._attr_device_info = DeviceInfo(model=provider.name, manufacturer=APPLICATION_NAME)
60        # Group players default to "no opinion" on power. The session lifecycle
61        # (form on play, dissolve on stop, debounced idle deform) governs whether
62        # the group is considered active. Users who want an explicit on/off button
63        # can assign 'Fake power control' which is then reflected via extra_data.
64        self._attr_powered = None
65        self._attr_needs_poll = True
66        # task that dissolves the group after the idle grace window expires
67        self._idle_grace_task: asyncio.Task[None] | None = None
68        # task that re-forms the group (debounced) after the sync leader was removed
69        self._reform_task: asyncio.Task[None] | None = None
70        # protocol hint for the debounced re-form, snapshotted before the old
71        # leader was cleared so the new leader keeps protocol continuity
72        self._reform_protocol_domain: str | None = None
73        # monotonic timestamp of the last playback start issued to the leader
74        # (-inf means never)
75        self._playback_start_at: float = float("-inf")
76        self._update_attributes()
77
78    @cached_property
79    def is_dynamic(self) -> bool:
80        """Return if the player is a dynamic group player."""
81        return bool(self.config.get_value(CONF_DYNAMIC_GROUP_MEMBERS, False))
82
83    @property
84    def synced_to(self) -> str | None:
85        """Return the id of the player this player is synced to (sync leader)."""
86        # groups can't be synced
87        return None
88
89    @property
90    def is_active_session(self) -> bool:
91        """
92        Return whether this sync group is currently holding its members.
93
94        The session is considered active while a sync leader is set (formed and
95        potentially playing/paused), while the idle grace timer is still
96        pending, or while a debounced re-form is pending. ``__final_active_group``
97        reads this to decide whether the configured members should be marked as
98        ``active_group`` for this group.
99        """
100        return (
101            self.sync_leader is not None
102            or self._idle_grace_task is not None
103            or self._reform_task is not None
104        )
105
106    async def on_config_updated(self) -> None:
107        """Handle logic when the PlayerConfig is first loaded or updated."""
108        # Config is only available after the player was registered
109        self._cache.clear()  # clear to prevent loading old is_dynamic
110        preset_members = cast("list[str]", self.config.get_value(CONF_GROUP_MEMBERS, []))
111        if self.is_dynamic:
112            # In dynamic mode the configured members act as a preset: they are
113            # pulled in when the group is powered on
114            self._attr_static_group_members = []
115            self._attr_supported_features.add(PlayerFeature.SET_MEMBERS)
116        else:
117            self._attr_static_group_members = list(preset_members)
118            self._attr_supported_features.discard(PlayerFeature.SET_MEMBERS)
119        # Only realign the effective member list to the preset when we are
120        # dormant. Otherwise a config save (e.g. user toggling an unrelated
121        # field) would wipe any dynamic joins that happened during this session.
122        if not self.is_active_session:
123            self._attr_group_members = list(preset_members)
124
125    @property
126    def supported_features(self) -> set[PlayerFeature]:
127        """Return the supported features of the player."""
128        # PlayerFeature.POWER is intentionally NOT advertised by default: it forces
129        # users to remember to power the group off to release its members, which
130        # makes "play X on a single member from HA" silently redirect to the whole
131        # group long after playback ended. The new lifecycle forms the group on
132        # play and dissolves it on stop (with a short idle grace), so explicit
133        # power control is no longer required.
134        # Users who DO want an explicit on/off button can assign 'Fake power
135        # control' in the player config; we then advertise POWER so the UI shows
136        # the toggle. The raw config value is read here to avoid recursion via
137        # the power_control property (which itself may inspect supported features).
138        base_features: set[PlayerFeature] = {PlayerFeature.PLAY_MEDIA}
139        raw_power_conf = self.mass.config.get_raw_player_config_value(
140            self.player_id, CONF_POWER_CONTROL
141        )
142        if raw_power_conf == PLAYER_CONTROL_FAKE:
143            base_features.add(PlayerFeature.POWER)
144        if self.is_dynamic:
145            base_features.add(PlayerFeature.SET_MEMBERS)
146        if self.sync_leader:
147            # add features supported by the sync leader
148            for feature in EXTRA_FEATURES_FROM_MEMBERS:
149                if feature in self.sync_leader.state.supported_features:
150                    base_features.add(feature)
151        else:
152            # derive features from all (configured) group members
153            # so that features like volume control are always advertised
154            for member_id in self._attr_group_members:
155                member_player = self.mass.players.get_player(member_id)
156                if member_player and member_player.state.available:
157                    for feature in EXTRA_FEATURES_FROM_MEMBERS:
158                        if feature in member_player.state.supported_features:
159                            base_features.add(feature)
160        return base_features
161
162    @property
163    def requires_flow_mode(self) -> bool:
164        """Return if the player needs flow mode."""
165        if leader := self.sync_leader:
166            return leader.flow_mode
167        return False
168
169    @property
170    def supported_sample_rates(self) -> list[tuple[int, int]] | None:
171        """Return supported sample rates as defined by the sync leader."""
172        # not cached: sync_leader can change during dynamic group reforms,
173        # so we always re-resolve to stay in sync with the current leader
174        if leader := self.sync_leader:
175            return leader.get_supported_sample_rates()
176        return [(44100, 16), (48000, 16)]
177
178    @property
179    def active_source(self) -> str | None:
180        """Return the active source id of the current media (if any)."""
181        # NOTE: Not using 'state' here as we need the 'raw' value provided by the sync leader player
182        if not self.sync_leader:
183            return None
184        # deal with output protocols on the sync leader
185        output_protocol_domain: str | None = None
186        if (
187            self.sync_leader.active_output_protocol
188            and self.sync_leader.active_output_protocol != "native"
189        ):
190            if protocol_player := self.mass.players.get_player(
191                self.sync_leader.active_output_protocol
192            ):
193                output_protocol_domain = protocol_player.provider.domain
194        # active source as reported by the player itself
195        if (
196            self.sync_leader.active_source
197            # try to catch cases where player reports an active source
198            # that is actually from an active output protocol (e.g. AirPlay)
199            and self.sync_leader.active_source.lower() != output_protocol_domain
200            and not (
201                # try to handle sendspin bridge where the player itself
202                # is reporting the bridged protocol as active source
203                # we need to ignore that
204                output_protocol_domain == "sendspin"
205                and (
206                    self.sync_leader.active_source.lower()
207                    in ("airplay", "cast", "chromecast", "network")
208                )
209            )
210        ):
211            return self.sync_leader.active_source
212        return None
213
214    @property
215    def source_list(self) -> list[PlayerSource]:
216        """Return list of available (native) sources for this player."""
217        # NOTE: Not using 'state' here as we need the 'raw' value provided by the sync leader player
218        return self.sync_leader.source_list if self.sync_leader else []
219
220    @property
221    def can_group_with(self) -> set[str]:
222        """Return the id's of players this player can group with."""
223        if not self.is_dynamic:
224            # in case of static members,
225            # we can only group with the players defined in the config, so we return those directly
226            return set(self._attr_static_group_members)
227        # Aggregate can_group_with from ALL current group members (not just the leader).
228        # A sync group can accommodate protocol switches, so a player compatible with
229        # ANY current member is a valid candidate to join.
230        member_ids = self._attr_group_members if self._attr_group_members else []
231        # current members bypass the allow-list filter (filter constrains joiners only)
232        current_members = set(member_ids)
233        can_group_with: set[str] = set()
234        for member_id in member_ids:
235            member_player = self.mass.players.get_player(member_id)
236            if member_player and member_player.state.available:
237                can_group_with.add(member_player.player_id)
238                can_group_with.update(member_player.state.can_group_with)
239        if can_group_with:
240            return {
241                pid
242                for pid in can_group_with
243                if pid in current_members or self._is_member_allowed(pid)
244            }
245        # Without any available member to derive compatibility from (empty group or
246        # all members offline), offer any compatible player.
247        # Actual compatibility is validated when adding members
248        can_group_with = set()
249        for player in self.mass.players.iter_players(return_unavailable=False):
250            if not player.available or player.type == PlayerType.GROUP:
251                # let's avoid showing group players as options to group with
252                continue
253            if (
254                PlayerFeature.SET_MEMBERS in player.state.supported_features
255                and player.state.can_group_with
256                and not player.state.active_group
257            ):
258                can_group_with.add(player.player_id)
259        return {pid for pid in can_group_with if self._is_member_allowed(pid)}
260
261    @property
262    def group_members(self) -> list[str]:
263        """Return the list of parent player id's that are part of this sync group."""
264        if (sync_leader := self.sync_leader) and sync_leader.state.group_members:
265            # use state.group_members here so protocol specific id's get correctly translated
266            return sync_leader.state.group_members
267        return self._attr_group_members
268
269    async def get_config_entries(self) -> list[ConfigEntry]:
270        """Return all (provider/player specific) Config Entries for the given player (if any)."""
271        # keep saved player ids so the UI can render a user friendly name
272        # prevents the bug where only the player ids show up during playback
273        saved_ids = {
274            *cast("list[str]", self.config.get_value(CONF_GROUP_MEMBERS, []) or []),
275            *cast("list[str]", self.config.get_value(CONF_ALLOWED_MEMBERS, []) or []),
276        }
277        possible_players = sorted(
278            [
279                ConfigValueOption(x.player_id, title=x.display_name)
280                for x in self.mass.players.all_players(True, False)
281                if x.type != PlayerType.GROUP
282                and (
283                    x.player_id in saved_ids
284                    or (
285                        PlayerFeature.SET_MEMBERS in x.state.supported_features
286                        # also include synced followers: can_group_with returns empty
287                        # while slaved, but the player is still group-capable
288                        and (x.state.can_group_with or x.state.synced_to)
289                    )
290                )
291            ],
292            key=lambda x: x.title or "",
293        )
294        entries: list[ConfigEntry] = [
295            # syncgroup specific entries
296            CONF_ENTRY_SGP_NOTE,
297            ConfigEntry(
298                key=CONF_GROUP_MEMBERS,
299                type=ConfigEntryType.STRING,
300                multi_value=True,
301                default_value=[],
302                required=False,  # needed for dynamic members (which allows empty members list)
303                options=possible_players,
304            ),
305            ConfigEntry(
306                key=CONF_DYNAMIC_GROUP_MEMBERS,
307                type=ConfigEntryType.BOOLEAN,
308                default_value=False,
309                required=False,
310            ),
311            ConfigEntry(
312                key=CONF_ALLOWED_MEMBERS,
313                type=ConfigEntryType.STRING,
314                multi_value=True,
315                default_value=[],
316                required=False,
317                options=possible_players,
318                depends_on=CONF_DYNAMIC_GROUP_MEMBERS,
319                advanced=True,
320            ),
321        ]
322        return entries
323
324    async def power(self, powered: bool) -> None:
325        """
326        Handle POWER command to group player.
327
328        Only called when the user has assigned a power control (native or fake)
329        to the group. Powering ON pre-forms the group so its members are
330        captured immediately (matching the legacy behaviour for users who opt
331        in). Powering OFF stops any playback and dissolves the group.
332
333        :param powered: True to power on (form/capture), False to power off (dissolve).
334        """
335        # always cancel any pending idle-grace timer on explicit power transitions
336        self._cancel_idle_grace_timer()
337
338        if not powered and self.playback_state in (
339            PlaybackState.PLAYING,
340            PlaybackState.PAUSED,
341        ):
342            # stop directly via the leader to avoid re-entering our own stop()
343            # logic (which would dissolve before we re-dissolve below).
344            if sync_leader := self.sync_leader:
345                await self.mass.players._handle_cmd_stop(sync_leader.player_id)
346
347        if powered:
348            # apply the configured preset members on power-on so unjoins
349            # during a powered session stick until the next power cycle
350            preset_members = cast("list[str]", self.config.get_value(CONF_GROUP_MEMBERS, []))
351            self._attr_group_members = [
352                *preset_members,
353                *[x for x in self._attr_group_members if x not in preset_members],
354            ]
355            # form syncgroup when powering on
356            await self._form_syncgroup()
357        else:
358            # dissolve syncgroup when powering off
359            await self._dissolve_syncgroup()
360
361        if self._attr_powered != powered:
362            self._attr_powered = powered
363            self._update_attributes()
364            self.update_state()
365
366    async def stop(self) -> None:
367        """
368        Send STOP command to given player.
369
370        An explicit stop on the group dissolves the syncgroup immediately so the
371        members are released back to individual control. The idle grace timer is
372        intentionally only used when the queue ends naturally (playback_state
373        transitions to IDLE without a stop command). Users who want the group
374        to stay formed across stops can assign Fake power control and use that
375        to pin the group as 'active'.
376        """
377        self._cancel_idle_grace_timer()
378        # an explicit stop also voids any pending debounced re-form and the
379        # startup marker — the user asked for silence
380        self._cancel_reform_timer()
381        self._playback_start_at = float("-inf")
382        self._attr_current_media = None
383        if sync_leader := self.sync_leader:
384            # Use internal handler to target the sync leader directly,
385            # bypassing group/sync redirect that would loop back to this player.
386            await self.mass.players._handle_cmd_stop(sync_leader.player_id)
387        # Skip the dissolve when the user has explicitly powered the group on
388        # via Fake power control — they expect the group to stay 'active' until
389        # they power it off, even after a stop.
390        if self._attr_powered is True:
391            return
392        await self._dissolve_syncgroup()
393
394    async def play(self) -> None:
395        """Send PLAY (unpause) command to given player."""
396        # The controller has already powered us on, but the group may not be
397        # formed (e.g. after _dissolve_and_reform left us powered with no leader).
398        # _form_syncgroup is idempotent so calling it here is cheap when already formed.
399        await self._form_syncgroup()
400        # Hold the group's playback lock until the leader actually reports playing
401        # so a concurrent (un)group command can't race the in-flight start — which
402        # would otherwise leave a player streaming outside the group.
403        async with self._await_leader_playback():
404            await self.mass.players.cmd_resume(
405                self.player_id, self._attr_active_source, self._attr_current_media
406            )
407
408    async def poll(self) -> None:
409        """Poll player for state updates."""
410        self._update_attributes()
411        self.update_state()
412
413    async def play_media(self, media: PlayerMedia) -> None:
414        """Handle PLAY MEDIA on given player."""
415        self._attr_current_media = media
416        self._attr_active_source = media.source_id or None
417        # The controller has already powered us on, but the group may not be
418        # formed (e.g. after _dissolve_and_reform left us powered with no leader).
419        # _form_syncgroup is idempotent so calling it here is cheap when already formed.
420        await self._form_syncgroup()
421        if sync_leader := self.sync_leader:
422            # Use internal handler to target the sync leader directly,
423            # bypassing group/sync redirect that would loop back to this player.
424            # Hold the group's playback lock until the leader confirms playback
425            # (see play()) so a concurrent (un)group command can't race the start.
426            async with self._await_leader_playback():
427                await self.mass.players._handle_play_media(sync_leader.player_id, media)
428        else:
429            raise RuntimeError("An empty group cannot play media, consider adding members first")
430
431    async def enqueue_next_media(self, media: PlayerMedia) -> None:
432        """Handle enqueuing of a next media item on the player."""
433        if sync_leader := self.sync_leader:
434            if PlayerFeature.ENQUEUE not in sync_leader.state.supported_features:
435                # this may happen in race conditions where we just switched sync leaders
436                # and the new leader doesn't support enqueueing next media.
437                return
438            # Use internal handler to bypass group redirect logic and avoid infinite loop
439            await self.mass.players._handle_enqueue_next_media(sync_leader.player_id, media)
440
441    async def set_members(  # noqa: PLR0915
442        self,
443        player_ids_to_add: list[str] | None = None,
444        player_ids_to_remove: list[str] | None = None,
445    ) -> None:
446        """Handle SET_MEMBERS command on the player."""
447        if not self.is_dynamic:
448            raise UnsupportedFeaturedException(
449                f"Group {self.display_name} does not allow dynamically adding/removing members!",
450                translation_key="not_dynamic",
451                translation_owner=self.translation_owner,
452                translation_args=[self.display_name],
453            )
454        sync_leader = self.sync_leader or self._select_sync_leader(new_members=player_ids_to_add)
455        # A start that was just issued to the leader may not be reflected in the
456        # (transient) device state yet, so treat the startup window as playing —
457        # otherwise a (un)group command racing an in-flight start misreads the
458        # group as idle and skips the resume. An explicit pause always wins:
459        # PAUSED is deliberate user intent, never startup noise.
460        was_playing = self.playback_state == PlaybackState.PLAYING or (
461            self.playback_state != PlaybackState.PAUSED and self._playback_recently_started
462        )
463
464        # handle additions
465        final_players_to_add: list[str] = []
466        can_group_with = sync_leader.state.can_group_with.copy() if sync_leader else set()
467        for member_id in player_ids_to_add or []:
468            if member_id == self.player_id:
469                continue  # can not add self as member
470            if not self._is_member_allowed(member_id):
471                self.logger.warning(
472                    "Player %s is not allowed to join group %s by the configured player filters, "
473                    "skipping adding it as a member to the group",
474                    member_id,
475                    self.display_name,
476                )
477                continue
478            member = self.mass.players.get_player(member_id)
479            if member is None or not member.available:
480                continue
481            if not sync_leader:
482                # no leader yet (e.g. empty group) - just register the member
483                # the leader and protocol selection happen on the next form/play
484                if member_id not in self._attr_group_members:
485                    self._attr_group_members.append(member_id)
486                continue
487            if member_id != sync_leader.player_id and member_id not in can_group_with:
488                # incompatible with the current leader's protocols - do NOT register
489                # the member or it will linger in _attr_group_members forever without
490                # ever actually being synced.
491                self.logger.debug(
492                    f"Cannot add {member.display_name} to group {self.display_name} since it's "
493                    f"not compatible with the (current) sync leader"
494                )
495                continue
496            if member_id not in self._attr_group_members:
497                self._attr_group_members.append(member_id)
498            if member_id != sync_leader.player_id:
499                final_players_to_add.append(member_id)
500
501        # handle removals
502        final_players_to_remove: list[str] = []
503        leader_removed = False
504        for member_id in player_ids_to_remove or []:
505            if member_id not in self._attr_group_members:
506                # Fallback for a member that was grouped to the sync leader
507                # outside of MA (e.g. via the Sonos app): it isn't part of our
508                # tracked member list but does show up in group_members via the
509                # leader's live state. Forward its removal to the sync leader
510                # instead of silently skipping it.
511                if (
512                    self.sync_leader
513                    and member_id != self.sync_leader.player_id
514                    and member_id in self.sync_leader.state.group_members
515                ):
516                    final_players_to_remove.append(member_id)
517                continue
518            if member_id in self._attr_static_group_members:
519                # static members can not be removed from the group
520                raise PlayerCommandFailed(
521                    f"Cannot remove {member_id} from group {self.display_name} "
522                    "since it's a static member!"
523                )
524            if self.sync_leader and member_id == self.sync_leader.player_id:
525                leader_removed = True
526                continue
527            if member_id == self.player_id:
528                raise PlayerCommandFailed(
529                    f"Cannot remove {self.display_name} from itself as a member!",
530                    translation_key="remove_self",
531                    translation_owner=self.translation_owner,
532                    translation_args=[self.display_name],
533                )
534            self._attr_group_members.remove(member_id)
535            final_players_to_remove.append(member_id)
536
537        if self.sync_leader and leader_removed and self._attr_group_members:
538            # we removed the current sync leader, but we still have members in the group
539            old_leader_id = self.sync_leader.player_id
540            session_player = self._active_session_player()
541            supports_handoff = (
542                session_player is not None
543                and session_player.provider.domain in PROVIDERS_WITH_DYNAMIC_LEADER_SWITCH
544            )
545
546            if was_playing and supports_handoff:
547                # protocol supports dynamic leader switching: try to remove
548                # only the departing leader and keep remaining members playing.
549                # _dynamic_leader_switch will fall back to dissolve+reform
550                # automatically if the chosen new leader isn't already part of
551                # the live session (e.g. a freshly-added player).
552                await self._dynamic_leader_switch(old_leader_id)
553            else:
554                # protocol doesn't support dynamic leader switching or not playing
555                await self._dissolve_and_reform(old_leader_id, resume_playback=was_playing)
556        elif self.sync_leader and (leader_removed or not self._attr_group_members):
557            # we removed the current sync leader, and we have no members left in the group
558            # or we just removed the last member from the group, so we dissolve the syncgroup
559            # Use internal handler to stop the sync leader directly,
560            # bypassing group redirect that would loop back to this player.
561            async with self.mass.players.wait_for_player_update(
562                self.sync_leader.player_id, timeout=5
563            ):
564                await self.mass.players._handle_cmd_stop(self.sync_leader.player_id)
565            await self._dissolve_syncgroup()
566
567        elif self.sync_leader:
568            # just a regular member(s) added/removed action,
569            # we can simply update the syncgroup members on the sync leader.
570            # `active_protocol_domain` is derived from live state, so the
571            # group will naturally downshift on the next leader selection if
572            # the last protocol-requiring member was removed.
573            # use _handle_set_members directly to avoid the redirect loop
574            # (cmd_set_members redirects sync-leader targets back to this syncgroup)
575            async with self.mass.players.get_player_lock(
576                self.sync_leader.player_id, PlayerLockPurpose.PLAYBACK
577            ):
578                await self.mass.players._handle_set_members(
579                    self.sync_leader,
580                    player_ids_to_add=final_players_to_add,
581                    player_ids_to_remove=final_players_to_remove,
582                )
583        elif self._reform_task is not None:
584            # leaderless with a debounced re-form pending: membership just changed,
585            # so re-arm the window — the re-form picks up the final member list.
586            self._schedule_reform_timer()
587        # NOTE: If we weren't playing before, we don't need to do anything else,
588        # since the syncing will be done once playback starts
589        self.mass.players.trigger_player_update(self.player_id)
590
591    def on_group_member_updated(
592        self, member_player: Player, changed_values: dict[str, tuple[Any, Any]]
593    ) -> None:
594        """Handle callback when a group member of the group player is updated."""
595        self._update_attributes()
596        super().on_group_member_updated(member_player, changed_values)
597
598    async def on_unload(self) -> None:
599        """Handle logic when the player is unloaded from the Player controller."""
600        self._cancel_idle_grace_timer()
601        self._cancel_reform_timer()
602        await super().on_unload()
603        # the player is going away; make sure we don't leave the protocol-level
604        # sync group standing with a now-nonexistent leader behind it.
605        if self.sync_leader is not None:
606            await self._dissolve_syncgroup()
607
608    @property
609    def active_protocol_domain(self) -> str | None:
610        """
611        Derive the active protocol domain for this sync group on the fly.
612
613        Returns the domain of the protocol currently carrying the live stream
614        session, EXCEPT when no remaining member actually requires that
615        non-native protocol — in which case the group should downshift and
616        this returns the leader's native provider domain. Always computed
617        from live state so it cannot drift from reality.
618        """
619        session_player = self._active_session_player()
620        if session_player is None or self.sync_leader is None:
621            return None
622        domain = session_player.provider.domain
623        native_domain = self.sync_leader.provider.domain
624        # If a non-native protocol is in use, only keep it as "active" for
625        # leader-selection purposes when some member still requires it.
626        if domain != native_domain and not self._any_member_requires_protocol_domain(domain):
627            return native_domain
628        return domain
629
630    def _is_member_allowed(self, player_id: str) -> bool:
631        """Return whether a player is allowed to join this group given the configured filter."""
632        # preset members should always be allowed to re-join
633        preset_members = cast("list[str]", self.config.get_value(CONF_GROUP_MEMBERS, []) or [])
634        if player_id in preset_members:
635            return True
636        allowed_members = cast("list[str]", self.config.get_value(CONF_ALLOWED_MEMBERS, []) or [])
637        return not allowed_members or player_id in allowed_members
638
639    async def _form_syncgroup(self) -> None:
640        """Form syncgroup by syncing all (possible) members."""
641        # any in-flight grace or debounced re-form timer is moot now —
642        # we're (re)forming the group
643        self._cancel_idle_grace_timer()
644        self._cancel_reform_timer()
645        self.logger.debug(
646            "Forming syncgroup %s, _attr_group_members=%s, sync_leader=%s",
647            self.display_name,
648            self._attr_group_members,
649            self.sync_leader.display_name if self.sync_leader else None,
650        )
651        # select new sync leader if needed
652        if not self.sync_leader:
653            self.sync_leader = self._select_sync_leader()
654
655        # pin the leader ref: a concurrent command (e.g. a dissolve) may clear
656        # or replace self.sync_leader while we await below
657        leader = self.sync_leader
658        if not leader:
659            # we have no members in the group, so we can't form a syncgroup
660            return
661
662        # ensure the sync leader is first in the list
663        self._attr_group_members = [
664            leader.player_id,
665            *[x for x in self._attr_group_members if x != leader.player_id],
666        ]
667        # If the leader still believes it's synced to a previous leader (e.g. we
668        # just picked a new leader after dissolving the old session and the
669        # protocol-level state hasn't propagated yet), wait for it to settle.
670        # Without this, the subsequent play_media call hits the provider's
671        # "I'm synced to another player" guard and gets rejected.
672        if leader.state.synced_to is not None:
673            self.logger.debug(
674                "Waiting for new leader %s to report synced_to=None before forming",
675                leader.display_name,
676            )
677            if not await self._wait_member_unsynced(leader.player_id):
678                # Leader is genuinely stuck — bail out before issuing play_media
679                # so we don't trigger the provider's "synced to another player"
680                # rejection. The caller (play / play_media) will surface this as
681                # a no-op form; the next user action can retry once the
682                # protocol layer has caught up.
683                self.logger.error(
684                    "Aborting syncgroup form for %s: leader %s is stuck synced",
685                    self.display_name,
686                    leader.display_name,
687                )
688                self.sync_leader = None
689                return
690            if self.sync_leader is not leader:
691                # the group was dissolved or re-led while we waited —
692                # this form attempt is stale, abort
693                return
694        # Translate the leader's group_members (may be protocol IDs) to parent IDs
695        # so we can compare against our _attr_group_members (always parent IDs)
696        already_synced = set(self._translate_to_parent_ids(leader.state.group_members))
697        members_to_sync = [
698            x for x in self._attr_group_members if x != leader.player_id and x not in already_synced
699        ]
700        if members_to_sync:
701            # If the sync leader is playing something independently, stop it first
702            # to prevent protocol switching from trying to resume the previous playback
703            # (we're about to start new playback on the syncgroup).
704            # Wait for the leader to actually reach IDLE before adding members,
705            # since some providers reject set_members while still playing.
706            if leader.state.playback_state == PlaybackState.PLAYING:
707                async with self.mass.players.wait_for_player_update(
708                    leader.player_id,
709                    attribute_name="playback_state",
710                    attribute_value=PlaybackState.IDLE,
711                    timeout=5,
712                ):
713                    await self.mass.players._handle_cmd_stop(leader.player_id)
714                if self.sync_leader is not leader:
715                    # the group was dissolved or re-led while we waited —
716                    # this form attempt is stale, abort
717                    return
718            # use _handle_set_members directly to avoid the redirect loop
719            # (cmd_set_members redirects sync-leader targets back to this syncgroup)
720            async with self.mass.players.get_player_lock(
721                leader.player_id, PlayerLockPurpose.PLAYBACK
722            ):
723                await self.mass.players._handle_set_members(
724                    leader, player_ids_to_add=members_to_sync
725                )
726
727    @asynccontextmanager
728    async def _await_leader_playback(self) -> AsyncIterator[None]:
729        """
730        Wait for the sync leader to confirm playback for the command run in the body.
731
732        Wrap the play/resume call that targets the leader in this context manager.
733        The group's playback lock (held by the caller) then stays acquired until the
734        leader actually reports playing, so a concurrent (un)group command cannot
735        race a start that has not yet taken effect at the device. A no-op when there
736        is no leader to wait on.
737        """
738        if (leader := self.sync_leader) is None:
739            yield
740            return
741        # stamp the start: device state is unreliable while a start settles, so
742        # group-command decisions treat this window as playing (see set_members)
743        self._playback_start_at = time.monotonic()
744        async with self.mass.players.wait_for_player_update(
745            leader.player_id,
746            attribute_name="playback_state",
747            attribute_value=PlaybackState.PLAYING,
748            timeout=PLAYBACK_START_TIMEOUT,
749        ):
750            yield
751
752    async def _dissolve_syncgroup(self) -> None:
753        """Dissolve the current syncgroup by ungrouping all members."""
754        # a dissolve is happening now — any pending grace or re-form timer is no
755        # longer needed (_dissolve_and_reform re-arms the re-form right after)
756        # and the session whose start the marker tracked is gone
757        self._cancel_idle_grace_timer()
758        self._cancel_reform_timer()
759        self._playback_start_at = float("-inf")
760        if sync_leader := self.sync_leader:
761            # dissolve the temporary syncgroup from the sync leader
762            sync_children = [
763                x for x in sync_leader.state.group_members if x != sync_leader.player_id
764            ]
765            if sync_children:
766                # wait for the leader's state to reflect the ungroup
767                # use _handle_set_members directly to avoid the redirect loop
768                # (cmd_set_members redirects sync-leader targets back to this syncgroup)
769                async with (
770                    self.mass.players.wait_for_player_update(sync_leader.player_id, timeout=5),
771                    self.mass.players.get_player_lock(
772                        sync_leader.player_id, PlayerLockPurpose.PLAYBACK
773                    ),
774                ):
775                    await self.mass.players._handle_set_members(
776                        sync_leader, player_ids_to_remove=sync_children
777                    )
778        # Clear the leader's active protocol once it stops playing; the controller's
779        # clearing in _handle_cmd_stop is skipped for a still-grouped protocol player.
780        if sync_leader:
781            self.mass.players.schedule_active_output_protocol_clear(sync_leader)
782        self.sync_leader = None
783        self._update_attributes()
784        self.update_state()
785
786    def _select_sync_leader(
787        self,
788        new_members: list[str] | None = None,
789        preferred_protocol_domain: str | None = None,
790    ) -> Player | None:
791        """
792        Select a (new) sync leader, preferring protocol continuity.
793
794        :param new_members: Optional list of newly added member ids to consider
795            when no current/static members are available.
796        :param preferred_protocol_domain: If provided, prefer members that
797            support this protocol domain so the live session can keep playing
798            on the same protocol. Typically a snapshot of
799            :attr:`active_protocol_domain` taken before the old leader is
800            cleared.
801        """
802        if self.group_members and self.sync_leader and self.sync_leader.state.available:
803            # current leader is still available, no need to select a new one
804            return self.sync_leader
805        # with selecting a new leader, we prioritize the static group members
806        group_members = self.static_group_members or self.group_members or new_members or []
807
808        # if a preferred protocol is given, prefer members that support it
809        if preferred_protocol_domain:
810            for member_id in group_members:
811                member_player = self.mass.players.get_player(member_id)
812                if (
813                    member_player
814                    and member_player.state.available
815                    and self._member_supports_protocol_domain(
816                        member_player, preferred_protocol_domain
817                    )
818                ):
819                    self.logger.debug(
820                        "Auto-selected %s as sync leader for group %s "
821                        "(supports active protocol %s)",
822                        member_player.display_name,
823                        self.display_name,
824                        preferred_protocol_domain,
825                    )
826                    return member_player
827
828        # fallback: pick any available member
829        for member_id in group_members:
830            member_player = self.mass.players.get_player(member_id)
831            if member_player and member_player.state.available:
832                self.logger.debug(
833                    f"Auto-selected {member_player.display_name} as sync leader for "
834                    f"group {self.display_name}"
835                )
836                return member_player
837        return None
838
839    # -----------------------------------------------------------------------
840    # Protocol awareness
841    # -----------------------------------------------------------------------
842    # A sync group can contain members from multiple protocol domains (e.g. a
843    # Sonos that can play via either its native protocol or via AirPlay). The
844    # group needs to:
845    #   - track which protocol the live session is using (active_protocol_domain)
846    #   - resolve which player actually owns the protocol-level session
847    #     (_active_session_player) so leader/handoff bookkeeping is done on
848    #     the right object
849    #   - choose new leaders that keep protocol continuity
850    #     (_member_supports_protocol_domain / _select_sync_leader)
851    #   - downshift to the native protocol when the last protocol-requiring
852    #     member is gone (_any_member_requires_protocol_domain)
853    # The helpers below cover those needs. Composition decisions (which protocol
854    # to use given the current member mix) intentionally live in the group:
855    # individual protocol providers don't have visibility into the rest of the
856    # group's members.
857
858    def _translate_to_parent_ids(self, player_ids: list[str]) -> list[str]:
859        """
860        Translate a list of (possibly protocol) player IDs to parent player IDs.
861
862        Protocol players (e.g. AirPlay `apc...`) are translated to their parent
863        (e.g. Sonos `RINCON_...`). Non-protocol IDs pass through unchanged.
864
865        :param player_ids: List of player IDs that may be protocol or parent IDs.
866        """
867        result: list[str] = []
868        for pid in player_ids:
869            if player := self.mass.players.get_player(pid):
870                parent_id = player.protocol_parent_id or pid
871                if parent_id not in result:
872                    result.append(parent_id)
873            elif pid not in result:
874                result.append(pid)
875        return result
876
877    def _member_supports_protocol_domain(self, player: Player, domain: str) -> bool:
878        """
879        Check if a player supports the given protocol domain.
880
881        :param player: The player to check.
882        :param domain: The protocol domain string (e.g. "airplay", "sonos").
883        """
884        if player.provider.domain == domain:
885            return True
886        for protocol in player.linked_output_protocols:
887            if protocol.protocol_domain == domain and protocol.available:
888                return True
889        return False
890
891    def _any_member_requires_protocol_domain(self, domain: str) -> bool:
892        """
893        Return True if any current member can only play via the given protocol domain.
894
895        A member "requires" the protocol when all of its available playback
896        paths are on that domain — i.e. it has no native playback path outside
897        this domain AND no linked output protocol outside this domain. This
898        covers plain protocol-domain players (e.g. AirPlay) as well as
899        UniversalPlayer wrappers whose native ``provider.domain`` is
900        ``universal_player`` but which can still only play via a single
901        linked protocol.
902
903        :param domain: The protocol domain string (e.g. "airplay", "sonos").
904        """
905        for member_id in self._attr_group_members:
906            member = self.mass.players.get_player(member_id)
907            if member is None or not member.state.available:
908                continue
909            # Collect the set of available playback path domains for this member.
910            paths: set[str] = set()
911            if member.is_native_player:
912                paths.add(member.provider.domain)
913            for protocol in member.linked_output_protocols:
914                if protocol.available:
915                    paths.add(protocol.protocol_domain)
916            if not paths:
917                # nothing available at all, skip rather than force a protocol
918                continue
919            if paths == {domain}:
920                return True
921        return False
922
923    def _active_session_player(self) -> Player | None:
924        """
925        Return the player that owns the live sync session.
926
927        If the current sync leader has a non-native active output protocol,
928        returns the protocol player that carries the stream; otherwise returns
929        the native sync leader itself. Returns ``None`` if there is no leader.
930        """
931        if not self.sync_leader:
932            return None
933        if (
934            self.sync_leader.active_output_protocol
935            and self.sync_leader.active_output_protocol != "native"
936            and (
937                protocol_player := self.mass.players.get_player(
938                    self.sync_leader.active_output_protocol
939                )
940            )
941        ):
942            return protocol_player
943        return self.sync_leader
944
945    def _update_attributes(self) -> None:
946        """Update dynamic attributes."""
947        # NOTE on what reads from `.state.*` vs the leader's raw attributes below:
948        # `__final_current_media` and `__final_active_source` on a player that has
949        # an ``active_group`` route through the active_group's state — so reading
950        # ``sync_leader.state.current_media`` from inside the group would loop
951        # back through our own state derivation (group → leader.state →
952        # active_group=group → group). For those two we MUST use the leader's
953        # raw attributes. ``playback_state`` / ``elapsed_time`` do not route via
954        # active_group and are safe to read from ``.state.*``.
955        if (sync_leader := self.sync_leader) is None:
956            # no sync leader, reset playback-related attributes to default values
957            self._attr_playback_state = PlaybackState.IDLE
958            self._attr_elapsed_time = None
959            self._attr_elapsed_time_last_updated = None
960            self._attr_current_media = None
961            self._attr_active_source = None
962            self._attr_poll_interval = 30
963            return
964        prev_state = self._attr_playback_state
965        new_state = sync_leader.state.playback_state
966        self._attr_playback_state = new_state
967        self._attr_elapsed_time = sync_leader.state.elapsed_time
968        self._attr_elapsed_time_last_updated = sync_leader.state.elapsed_time_last_updated
969        # don't use 'state' for current_media here since that points back to this group
970        # player when we're active_group, we need the 'raw' value from the sync leader
971        # itself to avoid circular dependency and ensure it reflects the actual media
972        # on the leader rather than the group.
973        self._attr_current_media = sync_leader.current_media
974        self._attr_active_source = sync_leader.active_source
975        self._attr_poll_interval = 1 if new_state == PlaybackState.PLAYING else 30
976        # idle grace handling: schedule a debounced dissolve when the leader
977        # naturally transitions from PLAYING/PAUSED to IDLE. The dissolve is
978        # skipped if the user has pinned the group with Fake power control.
979        if new_state == PlaybackState.IDLE and prev_state in (
980            PlaybackState.PLAYING,
981            PlaybackState.PAUSED,
982        ):
983            if self._attr_powered is not True:
984                self._schedule_idle_grace_timer()
985        elif new_state in (PlaybackState.PLAYING, PlaybackState.PAUSED):
986            # leader resumed playing, cancel any pending grace
987            self._cancel_idle_grace_timer()
988
989    def _is_player_in_session(self, player: Player, session_player: Player | None) -> bool:
990        """
991        Return True if ``player`` is already a sync_client of the live session.
992
993        A seamless leader handoff only works when the candidate's resolved
994        protocol player is already in the active ``AirPlayStreamSession`` (or
995        equivalent). If not (e.g. a freshly-added player that has never played
996        anything), we must fall back to dissolve + reform.
997
998        :param player: The candidate new leader.
999        :param session_player: The protocol player that owns the live session
1000            (snapshot taken before the old leader was cleared via
1001            ``_active_session_player()``).
1002        """
1003        if session_player is None:
1004            return False
1005        session = getattr(getattr(session_player, "stream", None), "session", None)
1006        if session is None:
1007            # No session object (e.g. Snapcast, Sendspin) — assume handoff is
1008            # safe if the provider declared support for it.
1009            return True
1010        sync_clients = getattr(session, "sync_clients", None)
1011        if sync_clients is None:
1012            # Session exists but doesn't expose sync_clients — same assumption.
1013            return True
1014        # Resolve player to the protocol player that would own the session
1015        target: Player = player
1016        if (
1017            player.active_output_protocol
1018            and player.active_output_protocol != "native"
1019            and (p := self.mass.players.get_player(player.active_output_protocol))
1020        ):
1021            target = p
1022        return target in sync_clients
1023
1024    async def _dissolve_and_reform(
1025        self,
1026        old_leader_id: str,
1027        leader_to_stop: Player | None = None,
1028        resume_playback: bool = True,
1029        preferred_protocol_domain: str | None = None,
1030    ) -> None:
1031        """
1032        Stop the current sync session, dissolve the syncgroup and schedule a re-form.
1033
1034        Used when a seamless handoff isn't possible (e.g. the new leader is not
1035        part of the live session). The stop/dissolve happens immediately; the
1036        re-form (with resume) is debounced so cascaded unjoins coalesce into a
1037        single restart with the final member list.
1038
1039        :param old_leader_id: The player_id of the departing leader.
1040        :param leader_to_stop: The player to stop before dissolving. Defaults
1041            to ``self.sync_leader`` but callers should pass the old leader
1042            explicitly when ``self.sync_leader`` has already been cleared.
1043        :param resume_playback: If True, schedule the debounced re-form which
1044            restarts playback on the new leader. Pass False when the group was
1045            not actively playing (e.g. paused or idle).
1046        :param preferred_protocol_domain: Optional snapshot of the active
1047            protocol domain taken before the old leader was cleared, passed to
1048            :meth:`_select_sync_leader` so the new leader is chosen to keep the
1049            protocol session continuous where possible.
1050        """
1051        leader_to_stop = leader_to_stop or self.sync_leader
1052        if leader_to_stop:
1053            self.logger.info(
1054                "Dissolving syncgroup %s (leader %s) and re-forming with a new leader",
1055                self.display_name,
1056                leader_to_stop.display_name,
1057            )
1058            async with self.mass.players.wait_for_player_update(
1059                leader_to_stop.player_id, timeout=5
1060            ):
1061                await self.mass.players._handle_cmd_stop(leader_to_stop.player_id)
1062        await self._dissolve_syncgroup()
1063        if old_leader_id in self._attr_group_members:
1064            self._attr_group_members.remove(old_leader_id)
1065        if resume_playback and self._attr_group_members:
1066            self._reform_protocol_domain = preferred_protocol_domain
1067            self._schedule_reform_timer()
1068
1069    async def _wait_member_unsynced(self, member_id: str, timeout: float = 5.0) -> bool:
1070        """
1071        Wait until the given member reports as unsynced (synced_to is None).
1072
1073        Returns ``True`` when the member is verified unsynced (downstream flows
1074        like leader selection / play_media on the leader are safe to proceed),
1075        or ``False`` when the player is genuinely stuck (the caller should
1076        abort rather than issue a play_media that will be rejected by the
1077        provider's "I'm synced to another player" guard).
1078
1079        :param member_id: The player to wait on.
1080        :param timeout: Seconds to wait for the first state propagation.
1081        """
1082        async with self.mass.players.wait_for_player_update(
1083            member_id,
1084            attribute_name="synced_to",
1085            attribute_value=None,
1086            timeout=timeout,
1087        ):
1088            pass
1089        member = self.mass.players.get_player(member_id)
1090        if member is None or member.synced_to is None:
1091            return True
1092        # The provider didn't propagate within the timeout. Kick the member
1093        # from its stale parent, then wait again with a tighter budget.
1094        # This rescues the common "Sonos UPnP event lag" case.
1095        # NOTE: not the public cmd_ungroup - it re-enters this syncgroup's set_members.
1096        # if the stale parent is gone, no kick is possible - fall through to the final check
1097        if stale_parent := self.mass.players.get_player(member.synced_to):
1098            self.logger.warning(
1099                "Player %s still reports synced_to=%s after %ss; "
1100                "removing it from its stale parent and re-waiting",
1101                member.display_name,
1102                member.synced_to,
1103                timeout,
1104            )
1105            try:
1106                async with (
1107                    self.mass.players.wait_for_player_update(
1108                        member_id,
1109                        attribute_name="synced_to",
1110                        attribute_value=None,
1111                        timeout=2.0,
1112                    ),
1113                    self.mass.players.get_player_lock(
1114                        stale_parent.player_id, PlayerLockPurpose.PLAYBACK
1115                    ),
1116                ):
1117                    await self.mass.players._handle_set_members(
1118                        stale_parent, player_ids_to_remove=[member_id]
1119                    )
1120            except asyncio.CancelledError:
1121                raise
1122            except Exception as err:
1123                self.logger.debug(
1124                    "stale-parent removal recovery for %s raised: %s", member.display_name, err
1125                )
1126        member = self.mass.players.get_player(member_id)
1127        if member is None or member.synced_to is None:
1128            return True
1129        self.logger.error(
1130            "Player %s is stuck synced_to=%s; aborting dissolve+reform path",
1131            member.display_name,
1132            member.synced_to,
1133        )
1134        return False
1135
1136    async def _dynamic_leader_switch(self, old_leader_id: str) -> None:
1137        """
1138        Switch the sync leader without tearing down the stream session.
1139
1140        Used when the provider supports dynamic leader selection (e.g. AirPlay,
1141        Snapcast). The old leader is removed from the live session and the
1142        remaining members keep playing uninterrupted on a newly selected leader.
1143
1144        If the selected new leader is not already part of the live session (e.g.
1145        a freshly-added player), a seamless handoff isn't possible. In that case
1146        we fall back to dissolve + reform, accepting a brief audio gap.
1147
1148        :param old_leader_id: The player_id of the leader being removed.
1149        """
1150        old_leader = self.sync_leader
1151        assert old_leader is not None
1152
1153        self.logger.info(
1154            "Dynamic leader switch: removing %s from group %s, remaining members keep playing",
1155            old_leader.display_name,
1156            self.display_name,
1157        )
1158
1159        # Snapshot the currently active protocol and session before clearing
1160        # the leader — we need both for new-leader selection and for the
1161        # handoff-eligibility check.
1162        preferred_domain = self.active_protocol_domain
1163        session_player = self._active_session_player()
1164
1165        # Remove the old leader from our group members list
1166        if old_leader_id in self._attr_group_members:
1167            self._attr_group_members.remove(old_leader_id)
1168
1169        # Pick a new leader preferring one that supports the currently active
1170        # protocol so the session continuation is seamless.
1171        self.sync_leader = None
1172        new_leader = self._select_sync_leader(preferred_protocol_domain=preferred_domain)
1173
1174        if not new_leader:
1175            # No remaining members to take over — stop the old leader's
1176            # session and dissolve the group entirely. Restore sync_leader
1177            # so _dissolve_syncgroup can properly ungroup protocol members.
1178            self.sync_leader = old_leader
1179            self.logger.info(
1180                "No remaining members for group %s after removing %s, stopping",
1181                self.display_name,
1182                old_leader.display_name,
1183            )
1184            async with self.mass.players.wait_for_player_update(old_leader.player_id, timeout=5):
1185                await self.mass.players._handle_cmd_stop(old_leader.player_id)
1186            await self._dissolve_syncgroup()
1187            return
1188
1189        # A seamless handoff requires the new leader to already be a
1190        # sync_client of the live session. If it's a freshly-added player
1191        # with no existing stream, fall back to dissolve + reform.
1192        if not self._is_player_in_session(new_leader, session_player):
1193            self.logger.info(
1194                "New leader %s is not in the live session; dissolving and re-forming syncgroup %s",
1195                new_leader.display_name,
1196                self.display_name,
1197            )
1198            # Restore sync_leader so _dissolve_and_reform -> _dissolve_syncgroup
1199            # can properly ungroup protocol-level members. Forward the protocol
1200            # hint so the new form keeps protocol continuity when possible.
1201            self.sync_leader = old_leader
1202            await self._dissolve_and_reform(
1203                old_leader_id,
1204                leader_to_stop=old_leader,
1205                preferred_protocol_domain=preferred_domain,
1206            )
1207            return
1208
1209        self.sync_leader = new_leader
1210        # Ensure the new leader is first in the members list
1211        self._attr_group_members = [
1212            new_leader.player_id,
1213            *[x for x in self._attr_group_members if x != new_leader.player_id],
1214        ]
1215        self.logger.info(
1216            "Dynamic leader switch complete: %s is now leader of group %s",
1217            new_leader.display_name,
1218            self.display_name,
1219        )
1220
1221        # Hand off at the protocol level. We already know:
1222        # - the old session player (the protocol player that owns the live session)
1223        # - the active protocol domain
1224        # - the new leader (a parent player whose protocol player is in the session)
1225        # So we can talk to the protocol players directly and skip the controller's
1226        # protocol-translation overhead in cmd_set_members.
1227        new_target = self._resolve_session_target(new_leader, preferred_domain)
1228        remaining_protocol_ids: list[str] = []
1229        for member_id in self._attr_group_members:
1230            if member_id == new_leader.player_id:
1231                continue
1232            if member := self.mass.players.get_player(member_id):
1233                if target := self._resolve_session_target(member, preferred_domain):
1234                    remaining_protocol_ids.append(target.player_id)
1235
1236        # 1. Old leader's session protocol player steps out of the session.
1237        # Direct call (the controller's cmd_set_members would interpret this
1238        # self-removal as "dissolve the entire group"). The provider's set_members
1239        # implementation handles "remove self while other clients remain" by
1240        # promoting another sync_client at the protocol level.
1241        if session_player is not None:
1242            await session_player.set_members(player_ids_to_remove=[session_player.player_id])
1243
1244        # 2. New leader's protocol player takes over ownership tracking of the
1245        # remaining members. The members are already in the live session at the
1246        # protocol level (sync_clients), this just transfers the bookkeeping so
1247        # the new leader's protocol player reports them as its group members.
1248        if remaining_protocol_ids and new_target is not None:
1249            await new_target.set_members(player_ids_to_add=remaining_protocol_ids)
1250
1251        self.update_state()
1252
1253    def _schedule_idle_grace_timer(self) -> None:
1254        """Schedule a debounced dissolve after the leader becomes idle."""
1255        # any previously scheduled task is replaced so we don't end up with
1256        # two dissolves racing each other when the leader oscillates quickly
1257        self._cancel_idle_grace_timer()
1258        self.logger.debug(
1259            "Scheduling idle-grace dissolve for syncgroup %s in %ss",
1260            self.display_name,
1261            IDLE_GRACE_SECONDS,
1262        )
1263        self._idle_grace_task = self.mass.create_task(self._idle_grace_runner())
1264
1265    def _cancel_idle_grace_timer(self) -> None:
1266        """Cancel any pending idle-grace dissolve task."""
1267        if self._idle_grace_task is not None:
1268            if not self._idle_grace_task.done():
1269                self._idle_grace_task.cancel()
1270            self._idle_grace_task = None
1271
1272    async def _idle_grace_runner(self) -> None:
1273        """Wait the grace window, then dissolve if the group is still idle."""
1274        try:
1275            await asyncio.sleep(IDLE_GRACE_SECONDS)
1276        except asyncio.CancelledError:
1277            return
1278        # re-check state at fire time — playback may have resumed, the user
1279        # may have powered the group on, or another path may have dissolved
1280        # us already. Any of these means we should not dissolve here.
1281        self._idle_grace_task = None
1282        if self.sync_leader is None:
1283            return
1284        if self._attr_powered is True:
1285            return
1286        if self.sync_leader.state.playback_state != PlaybackState.IDLE:
1287            return
1288        self.logger.info(
1289            "Idle-grace expired for syncgroup %s, dissolving",
1290            self.display_name,
1291        )
1292        await self._dissolve_syncgroup()
1293
1294    @property
1295    def _playback_recently_started(self) -> bool:
1296        """Return whether a playback start was issued within the settle window."""
1297        return (time.monotonic() - self._playback_start_at) < PLAYBACK_START_TIMEOUT
1298
1299    def _schedule_reform_timer(self) -> None:
1300        """(Re)schedule the debounced re-form after the sync leader was removed."""
1301        # any previously scheduled task is replaced so cascaded unjoins coalesce
1302        # into a single re-form with the final member list
1303        self._cancel_reform_timer()
1304        self.logger.debug(
1305            "Scheduling debounced re-form for syncgroup %s in %ss",
1306            self.display_name,
1307            REFORM_DEBOUNCE_SECONDS,
1308        )
1309        self._reform_task = self.mass.create_task(self._reform_runner())
1310
1311    def _cancel_reform_timer(self) -> None:
1312        """Cancel any pending debounced re-form task."""
1313        if (task := self._reform_task) is None:
1314            return
1315        self._reform_task = None
1316        # never cancel ourselves: the runner ends up here via play() -> _form_syncgroup
1317        if task is not asyncio.current_task() and not task.done():
1318            task.cancel()
1319
1320    async def _reform_runner(self) -> None:
1321        """Wait the debounce window, then re-form the group and resume playback."""
1322        try:
1323            await asyncio.sleep(REFORM_DEBOUNCE_SECONDS)
1324        except asyncio.CancelledError:
1325            return
1326        try:
1327            # serialize with (un)group and playback commands targeting this group.
1328            # A cancellation (another unjoin re-arming the window, an explicit
1329            # stop) may still land while we wait for the lock.
1330            async with self.mass.players.get_player_lock(
1331                self.player_id, PlayerLockPurpose.PLAYBACK
1332            ):
1333                # re-check state at execution time — an explicit play may have
1334                # re-formed the group already and all members may have been
1335                # removed meanwhile
1336                if self.sync_leader is not None or not self._attr_group_members:
1337                    return
1338                # Wait for the remaining members to report as unsynced before
1339                # re-forming. Providers like Sonos propagate group state
1340                # asynchronously — the children can still report synced_to for
1341                # a few seconds after the leader's ungroup command returns.
1342                members = list(self._attr_group_members)
1343                unsync_results = await asyncio.gather(
1344                    *(self._wait_member_unsynced(m) for m in members),
1345                    return_exceptions=True,
1346                )
1347                stuck_members = [
1348                    members[i] for i, result in enumerate(unsync_results) if result is False
1349                ]
1350                if stuck_members:
1351                    self.logger.error(
1352                        "Members of group %s still report synced_to after recovery attempts: "
1353                        "%s; aborting re-form (no playback will resume on this call)",
1354                        self.display_name,
1355                        stuck_members,
1356                    )
1357                    return
1358                self.logger.info(
1359                    "Re-forming syncgroup %s with %s member(s) and resuming playback",
1360                    self.display_name,
1361                    len(members),
1362                )
1363                # Preselect the new leader with the protocol hint so the form
1364                # picks a member compatible with the previous session's protocol
1365                # (e.g. keep AirPlay if the session was AirPlay).
1366                if self._reform_protocol_domain is not None:
1367                    self.sync_leader = self._select_sync_leader(
1368                        preferred_protocol_domain=self._reform_protocol_domain
1369                    )
1370                await self.play()
1371        finally:
1372            # normal completion detaches us via play() -> _form_syncgroup already;
1373            # this covers the early-return paths so is_active_session settles
1374            if self._reform_task is asyncio.current_task():
1375                self._reform_task = None
1376                self.update_state()
1377
1378    def _resolve_session_target(self, player: Player, domain: str | None) -> Player | None:
1379        """
1380        Resolve the player that participates in the live session for ``domain``.
1381
1382        For a player whose own provider domain matches, returns the player itself.
1383        For a parent player with a linked protocol on that domain, returns the
1384        corresponding protocol player. Returns ``None`` when nothing matches.
1385
1386        :param player: The player to resolve (parent or protocol player).
1387        :param domain: The protocol domain string of the active session
1388            (e.g. "airplay"). May be None, in which case ``player`` is returned.
1389        """
1390        if domain is None:
1391            return player
1392        if player.provider.domain == domain:
1393            return player
1394        for linked in player.linked_output_protocols:
1395            if linked.protocol_domain == domain and linked.available:
1396                return self.mass.players.get_player(linked.output_protocol_id)
1397        return None
1398