music-assistant-server

1"""
2Protocol Linking Mixin for the Player Controller.
3
4Handles all logic for linking protocol players (AirPlay, Chromecast, DLNA) to
5native players or wrapping them in Universal Players.
6
7This module provides the ProtocolLinkingMixin class which is inherited by
8PlayerController to add protocol linking capabilities.
9"""
10
11from __future__ import annotations
12
13import asyncio
14import logging
15from contextlib import suppress
16from copy import deepcopy
17from typing import TYPE_CHECKING, cast
18
19from music_assistant_models.enums import (
20    EventType,
21    IdentifierType,
22    PlaybackState,
23    PlayerFeature,
24    PlayerType,
25    ProviderType,
26)
27from music_assistant_models.errors import PlayerCommandFailed, PlayerUnavailableError
28
29from music_assistant.constants import (
30    CONF_CACHED_ARP_MAC,
31    CONF_GROUP_MEMBERS,
32    CONF_LINKED_PROTOCOL_IDS,
33    CONF_PLAYER_DSP,
34    CONF_PLAYER_QUEUES,
35    CONF_PLAYERS,
36    CONF_PREFERRED_OUTPUT_PROTOCOL,
37    CONF_PROTOCOL_KEY_SPLITTER,
38    CONF_PROTOCOL_PARENT_ID,
39    CONF_REPORTED_MAC,
40    CONF_UNDERLYING_PLAYER_ID,
41    PROTOCOL_PRIORITY,
42    VERBOSE_LOG_LEVEL,
43)
44from music_assistant.helpers.util import (
45    is_locally_administered_mac,
46    is_valid_mac_address,
47    normalize_mac_for_matching,
48)
49from music_assistant.models.player import LinkedOutputProtocol, Player
50from music_assistant.providers.sync_group.constants import CONF_ALLOWED_MEMBERS
51from music_assistant.providers.universal_player import UniversalPlayer, UniversalPlayerProvider
52from music_assistant.providers.universal_player.constants import (
53    CONF_CREATED_AT,
54    CONF_DEVICE_IDENTIFIERS,
55    CONF_DEVICE_INFO,
56)
57
58if TYPE_CHECKING:
59    from collections.abc import Coroutine
60    from typing import Any
61
62    from music_assistant_models.player import OutputProtocol
63
64    from music_assistant import MusicAssistant
65
66# Config value keys that are bookkeeping of the universal player wrapper itself
67# (protocol links, device-identity caches and its creation moment) and must never
68# be carried over when a native player replaces a universal player, or when one
69# universal player absorbs another.
70UNIVERSAL_PLAYER_INTERNAL_CONF_KEYS = (
71    CONF_LINKED_PROTOCOL_IDS,
72    CONF_PROTOCOL_PARENT_ID,
73    CONF_UNDERLYING_PLAYER_ID,
74    CONF_DEVICE_IDENTIFIERS,
75    CONF_DEVICE_INFO,
76    CONF_CACHED_ARP_MAC,
77    CONF_REPORTED_MAC,
78    CONF_CREATED_AT,
79)
80
81
82class ProtocolLinkingMixin:
83    """
84    Mixin class providing protocol linking functionality for PlayerController.
85
86    Handles the complex logic of:
87    - Matching protocol players to native players via device identifiers
88    - Creating Universal Players for devices without native support
89    - Managing protocol links and their lifecycle
90    - Selecting the best output protocol for playback
91
92    This mixin expects to be mixed with a class that provides:
93    - mass: MusicAssistant instance
94    - _players: dict of registered players
95    - _pending_protocol_evaluations: dict of pending protocol evaluations
96    - logger: logging.Logger instance
97    - all(): method to get all players
98    - get(): method to get a player by ID
99    - unregister(): method to unregister a player
100    """
101
102    # Type hints for attributes provided by the class this mixin is used with
103    if TYPE_CHECKING:
104        mass: MusicAssistant
105        _players: dict[str, Player]
106        _pending_protocol_evaluations: dict[str, asyncio.TimerHandle]
107        _delayed_evaluation_lock: asyncio.Lock
108        logger: logging.Logger
109
110        def all_players(  # noqa: D102
111            self,
112            return_unavailable: bool = True,
113            return_disabled: bool = False,
114            provider_filter: str | None = None,
115            return_protocol_players: bool = False,
116        ) -> list[Player]: ...
117
118        def get_player(self, player_id: str) -> Player | None: ...  # noqa: D102
119
120        def unregister(  # noqa: D102
121            self, player_id: str, permanent: bool = False
122        ) -> Coroutine[Any, Any, None]: ...
123
124    def _is_protocol_player(self, player: Player) -> bool:
125        """
126        Check if a player is a generic protocol player without native support.
127
128        Protocol players have PlayerType.PROTOCOL set by their provider, indicating
129        they are generic streaming endpoints (e.g., AirPlay receiver, Chromecast device)
130        without vendor-specific native support in Music Assistant.
131        """
132        return player.state.type == PlayerType.PROTOCOL
133
134    def _evaluate_protocol_links(self, player: Player) -> None:
135        """
136        Evaluate and establish protocol links for a player.
137
138        Called when a player is registered to:
139        1. If it's from a protocol provider - try to link to a native player.
140        2. If it's a native player - try to link any existing protocol players.
141        """
142        if player.state.type == PlayerType.PROTOCOL:
143            # Protocol player: try to find a native parent
144            self._try_link_protocol_to_native(player)
145        elif player.state.type == PlayerType.GROUP:
146            return
147        else:
148            # A player that registers with a non-protocol type can no longer be a
149            # protocol child: drop a leftover persisted parent link (e.g. from a
150            # bridge client that turned web player) so the startup repair pass
151            # doesn't heal its player type back to protocol.
152            if self._get_cached_protocol_parent_id(player.player_id):
153                self._clear_protocol_parent_id(player.player_id)
154            # Native player (including STEREO_PAIR): try to find protocol players to link
155            self._try_link_protocols_to_native(player)
156
157    def _try_link_protocol_to_native(self, protocol_player: Player) -> None:
158        """Try to link a protocol player to a native player."""
159        protocol_domain = protocol_player.provider.domain
160
161        # Derived protocol players (e.g. Sendspin bridges riding on another
162        # protocol) resolve strictly via their underlying player - no identifier
163        # matching or delayed evaluation. If the underlying player has no parent
164        # yet, the link is established by _link_derived_protocols_of as soon as
165        # the underlying player gets linked.
166        if protocol_player.underlying_player_id:
167            self._try_link_derived_protocol(protocol_player)
168            return
169
170        # Check for cached parent_id from previous session and restore link immediately
171        cached_parent_id = self._get_cached_protocol_parent_id(protocol_player.player_id)
172        if cached_parent_id:
173            result = self._try_restore_cached_parent(
174                protocol_player, cached_parent_id, protocol_domain
175            )
176            if result:
177                return
178            # Link was refused or parent has active domain - fall through to search
179
180        # Look for a matching native player
181        if self._try_link_to_existing_player(protocol_player, protocol_domain):
182            return
183
184        # No native player found - schedule delayed evaluation to allow other protocols to register
185        if not protocol_player.protocol_parent_id:
186            self._schedule_protocol_evaluation(protocol_player)
187
188    def _try_restore_cached_parent(
189        self, protocol_player: Player, cached_parent_id: str, protocol_domain: str
190    ) -> bool:
191        """
192        Try to restore a cached parent link from a previous session.
193
194        :param protocol_player: The protocol player to link.
195        :param cached_parent_id: The cached parent player ID.
196        :param protocol_domain: The protocol domain (e.g., "airplay").
197        :return: True if handled (linked or waiting), False if should fall through.
198        """
199        if parent_player := self.get_player(cached_parent_id):
200            if parent_player.state.type == PlayerType.GROUP:
201                self._clear_protocol_parent_id(protocol_player.player_id)
202                return False
203            already_linked = any(
204                link.output_protocol_id == protocol_player.player_id
205                for link in parent_player.linked_output_protocols
206            )
207            if already_linked:
208                # Already linked from a previous call - just restore parent and identifiers
209                protocol_player.set_protocol_parent_id(cached_parent_id)
210            else:
211                # Try to add the link (may be refused if domain already has active link)
212                self._add_protocol_link(parent_player, protocol_player, protocol_domain)
213            if protocol_player.protocol_parent_id:
214                protocol_player.refresh_state()
215                parent_player.refresh_state()
216                # Merge the protocol player's identifiers into the universal player
217                # so identifiers discovered since the last persist (e.g. an
218                # ARP-resolved MAC) are included and new protocol players
219                # (like Sendspin bridges) can match via identifiers.
220                if parent_player.provider.domain == "universal_player" and isinstance(
221                    parent_player, UniversalPlayer
222                ):
223                    for conn_type, value in protocol_player.device_info.identifiers.items():
224                        parent_player.device_info.add_identifier(conn_type, value)
225                    self._update_universal_device_info(parent_player, protocol_player)
226                    # Check if this universal player should now be merged with another
227                    # (e.g., DLNA brought a MAC via ARP that matches an AirPlay universal)
228                    self._check_merge_universal_players(parent_player)
229                return True
230            # Link was refused (domain already active on parent) - fall through
231            return False
232
233        # Parent is not registered yet. Leave the protocol player unparented
234        # so the caller schedules delayed evaluation, which can wait for the
235        # cached parent without stranding the protocol player on a dangling id.
236        return False
237
238    def _try_link_to_existing_player(self, protocol_player: Player, protocol_domain: str) -> bool:
239        """
240        Try to link a protocol player to an existing native or universal player.
241
242        :param protocol_player: The protocol player to link.
243        :param protocol_domain: The protocol domain (e.g., "airplay").
244        :return: True if linked successfully, False if no match found.
245        """
246        # Protocol players should only link to:
247        # 1. True native players (Sonos, etc.)
248        # 2. Universal players
249        # NOT to other protocol players (they get merged via universal_player)
250        for native_player in self.all_players(return_protocol_players=False):
251            if native_player.player_id == protocol_player.player_id:
252                continue
253            if native_player.state.type in (PlayerType.PROTOCOL, PlayerType.GROUP):
254                continue
255
256            # For universal players, check if this protocol player is in its stored list
257            # or if identifiers match (for new protocol players like Sendspin bridges
258            # that weren't previously known to the Universal Player)
259            if native_player.provider.domain == "universal_player":
260                if isinstance(native_player, UniversalPlayer):
261                    is_known = protocol_player.player_id in native_player._protocol_player_ids
262                    is_match = not is_known and self._identifiers_match(
263                        native_player, protocol_player, protocol_domain
264                    )
265                    if is_known or is_match:
266                        self._add_protocol_link(native_player, protocol_player, protocol_domain)
267                        # Check if linking actually succeeded (may be refused for
268                        # duplicate domain)
269                        if not protocol_player.protocol_parent_id:
270                            continue
271                        # Merge the protocol player's identifiers into the universal
272                        # player so newly discovered identifiers are included as well
273                        for conn_type, value in protocol_player.device_info.identifiers.items():
274                            native_player.device_info.add_identifier(conn_type, value)
275                        # Update model/manufacturer if universal player has generic values
276                        self._update_universal_device_info(native_player, protocol_player)
277                        # Register newly matched protocol player with the universal player
278                        if is_match:
279                            native_player.add_protocol_player(protocol_player.player_id)
280                        # Persist updated data to config (async via task)
281                        self._save_universal_player_data(native_player)
282                        # Check if this universal player should now be merged with another
283                        self._check_merge_universal_players(native_player)
284                        protocol_player.refresh_state()
285                        native_player.refresh_state()
286                        return True
287                continue
288
289            # Check cached protocol IDs first for fast matching on restart
290            cached_ids = self._get_cached_protocol_ids(native_player.player_id)
291            if protocol_player.player_id in cached_ids:
292                self._add_protocol_link(native_player, protocol_player, protocol_domain)
293                if protocol_player.protocol_parent_id:
294                    protocol_player.refresh_state()
295                    native_player.refresh_state()
296                    return True
297                # Link refused (domain duplicate) - try next native player
298                continue
299
300            # Fallback to identifier matching
301            if self._identifiers_match(native_player, protocol_player, protocol_domain):
302                self._add_protocol_link(native_player, protocol_player, protocol_domain)
303                if protocol_player.protocol_parent_id:
304                    protocol_player.refresh_state()
305                    native_player.refresh_state()
306                    return True
307                # Link refused (domain duplicate) - try next native player
308                continue
309
310            # Final fallback: check if any already-linked protocol player on this native
311            # player shares identifiers with the new protocol player ("sibling matching").
312            # This handles native players (e.g., HEOS) that don't have their own MAC/serial
313            # identifiers but have protocol players (e.g., AirPlay) from the same device
314            # that do share identifiers with the new protocol player (e.g., Sendspin bridge).
315            if self._match_via_linked_protocols(native_player, protocol_player, protocol_domain):
316                return True
317
318        return False
319
320    def _match_via_linked_protocols(
321        self,
322        native_player: Player,
323        protocol_player: Player,
324        protocol_domain: str,
325    ) -> bool:
326        """
327        Try to match a protocol player to a native player via sibling protocol identifiers.
328
329        Check if any of the native player's already-linked protocol players share
330        identifiers with the new protocol player. This handles native players that lack
331        their own device identifiers but have sibling protocols from the same physical device.
332
333        :param native_player: The native player to potentially link to.
334        :param protocol_player: The new protocol player to link.
335        :param protocol_domain: The protocol domain of the new player.
336        :return: True if linked successfully, False if no match found.
337        """
338        for linked in native_player.linked_output_protocols:
339            linked_player = self.get_player(linked.output_protocol_id)
340            if not linked_player:
341                continue
342            if self._identifiers_match(linked_player, protocol_player, protocol_domain):
343                self._add_protocol_link(native_player, protocol_player, protocol_domain)
344                if protocol_player.protocol_parent_id:
345                    protocol_player.refresh_state()
346                    native_player.refresh_state()
347                    return True
348                # Link refused (domain duplicate) - stop checking siblings
349                break
350        return False
351
352    def _try_link_derived_protocol(self, protocol_player: Player) -> bool:
353        """
354        Link a derived protocol player to the parent of its underlying player.
355
356        Derived protocol players carry an underlying_player_id declared by their
357        bridge, which makes the parent resolution deterministic: they always join
358        the parent of the player they ride on (or that player itself when it is
359        not a protocol player). Callers must ensure the player is not linked yet.
360
361        :param protocol_player: The derived protocol player to link.
362        :return: True if the player got linked, False if the underlying player
363            (or its parent) is not available yet or the link was refused.
364        """
365        underlying = self.get_player(protocol_player.underlying_player_id or "")
366        if underlying is None:
367            return False
368        if underlying.state.type == PlayerType.PROTOCOL:
369            parent = (
370                self.get_player(underlying.protocol_parent_id)
371                if underlying.protocol_parent_id
372                else None
373            )
374        else:
375            parent = underlying
376        if parent is None or parent.state.type == PlayerType.GROUP:
377            return False
378
379        self._add_protocol_link(parent, protocol_player, protocol_player.provider.domain)
380        if not protocol_player.protocol_parent_id:
381            # Link refused (e.g. parent already has an active link from this domain)
382            return False
383
384        if parent.provider.domain == "universal_player" and isinstance(parent, UniversalPlayer):
385            # Track membership and identifiers on the universal player so the
386            # derived protocol restores quickly on the next start.
387            parent.add_protocol_player(protocol_player.player_id)
388            for conn_type, value in protocol_player.device_info.identifiers.items():
389                parent.device_info.add_identifier(conn_type, value)
390            self._save_universal_player_data(parent)
391
392        protocol_player.refresh_state()
393        parent.refresh_state()
394        self.logger.debug(
395            "Linked derived protocol %s to %s (via underlying %s)",
396            protocol_player.player_id,
397            parent.player_id,
398            underlying.player_id,
399        )
400        return True
401
402    def _link_derived_protocols_of(self, underlying_player: Player) -> None:
403        """
404        Link any waiting derived protocol players that ride on the given player.
405
406        Called after a player is linked to a parent (or registered as a native
407        player), so derived protocol players that registered earlier can join
408        the same parent.
409        """
410        for candidate in self.all_players(return_protocol_players=True):
411            if candidate.underlying_player_id != underlying_player.player_id:
412                continue
413            if candidate.protocol_parent_id:
414                continue
415            self._try_link_derived_protocol(candidate)
416
417    def _schedule_protocol_evaluation(self, protocol_player: Player) -> None:
418        """
419        Schedule a delayed protocol evaluation.
420
421        Delays evaluation to allow other protocol players and native players to register.
422        Uses a longer delay (30s) if this protocol player was previously linked to a native
423        player that hasn't registered yet, giving native providers time to start up.
424        """
425        player_id = protocol_player.player_id
426
427        # Cancel any existing pending evaluation for this player
428        if player_id in self._pending_protocol_evaluations:
429            self._pending_protocol_evaluations[player_id].cancel()
430
431        # Check if this protocol player has a cached parent (was previously linked)
432        cached_parent_id = self._get_cached_protocol_parent_id(player_id)
433        if cached_parent_id and not self.get_player(cached_parent_id):
434            # Previously linked to a native player that hasn't registered yet
435            # Use longer delay to give native providers time to start up
436            delay = 45.0
437            self.logger.debug(
438                "Protocol player %s waiting for cached parent %s (45s delay)",
439                player_id,
440                cached_parent_id,
441            )
442        else:
443            # Standard delay for protocol player discovery
444            # Allows time for other protocols and native players to register
445            delay = 15.0
446
447        # Schedule evaluation after the delay
448        handle = self.mass.loop.call_later(
449            delay,
450            lambda: self.mass.create_task(self._delayed_protocol_evaluation(player_id)),
451        )
452        self._pending_protocol_evaluations[player_id] = handle
453
454    async def _delayed_protocol_evaluation(self, player_id: str) -> None:
455        """
456        Perform delayed protocol evaluation.
457
458        Called after a delay to allow all protocol players for a device to register.
459        Decides whether to create a universal player, join an existing one, or
460        promote a single protocol player directly.
461
462        Uses a shared lock to serialize evaluations - multiple protocol players from the
463        same device may trigger concurrent evaluations that would otherwise race each other.
464        """
465        self._pending_protocol_evaluations.pop(player_id, None)
466
467        async with self._delayed_evaluation_lock:
468            protocol_player = self.get_player(player_id)
469            if not protocol_player or protocol_player.protocol_parent_id:
470                return
471            if protocol_player.state.type != PlayerType.PROTOCOL:
472                # The player changed type while the evaluation was pending
473                # (e.g. re-registered as a regular player); it must never be
474                # linked as a protocol or wrapped in a universal player.
475                return
476
477            # Derived protocol players resolve strictly via their underlying
478            # player and never match by identifiers or wrap into universal
479            # players; they wait for _link_derived_protocols_of otherwise.
480            if protocol_player.underlying_player_id:
481                self._try_link_derived_protocol(protocol_player)
482                return
483
484            protocol_domain = protocol_player.provider.domain
485
486            # Re-try linking to an existing native/universal player
487            if self._try_link_to_existing_player(protocol_player, protocol_domain):
488                return
489
490            # Check if there's an existing universal player we should join
491            if existing_universal := self._find_matching_universal_player(protocol_player):
492                await self._add_protocol_to_existing_universal(
493                    existing_universal, protocol_player, protocol_domain
494                )
495                if protocol_player.protocol_parent_id is not None:
496                    return
497                # Link refused (domain duplicate) - fall through to create separate UP
498
499            # Refuse to create a universal player wrapper when the cached parent
500            # config exists but is disabled. The user explicitly turned the
501            # parent device off; surfacing its protocols as a separate player
502            # would defeat that intent.
503            cached_parent_id = self._get_cached_protocol_parent_id(player_id)
504            if cached_parent_id:
505                parent_raw = self.mass.config.get(f"{CONF_PLAYERS}/{cached_parent_id}")
506                if parent_raw and not parent_raw.get("enabled", True):
507                    self.logger.debug(
508                        "Skipping universal player creation for %s: cached parent %s is disabled",
509                        player_id,
510                        cached_parent_id,
511                    )
512                    return
513
514            # Find all protocol players that match this device's identifiers
515            matching_protocols = self._find_matching_protocol_players(protocol_player)
516
517            # Create or update UniversalPlayer for all protocol players
518            await self._create_or_update_universal_player(matching_protocols)
519
520    def _find_matching_protocol_players(self, protocol_player: Player) -> list[Player]:
521        """
522        Find all protocol players that match the same device as the given player.
523
524        Searches through all registered protocol players to find ones that share
525        identifiers (MAC, IP, UUID) with the given player, indicating they represent
526        the same physical device.
527        """
528        matching = [protocol_player]
529        protocol_domain = protocol_player.provider.domain
530
531        for other_player in self.all_players(return_protocol_players=True):
532            if other_player.player_id == protocol_player.player_id:
533                continue
534            if other_player.state.type != PlayerType.PROTOCOL:
535                continue
536            if other_player.protocol_parent_id:
537                continue
538            if other_player.underlying_player_id:
539                # Derived protocol players follow their underlying player
540                # once it is linked; they never seed a universal player.
541                continue
542            # Skip players from the same protocol domain
543            # Multiple instances of the same protocol on one host are separate players
544            if other_player.provider.domain == protocol_domain:
545                continue
546            if self._identifiers_match(protocol_player, other_player):
547                matching.append(other_player)
548
549        return matching
550
551    def _find_matching_universal_player(self, protocol_player: Player) -> Player | None:
552        """Find an existing universal player that matches this protocol player."""
553        for player in self._players.values():
554            if not isinstance(player, UniversalPlayer):
555                continue
556            if self._identifiers_match(protocol_player, player, ""):
557                return player
558        return None
559
560    async def _add_protocol_to_existing_universal(
561        self, universal_player: Player, protocol_player: Player, protocol_domain: str
562    ) -> None:
563        """Add a protocol player to an existing universal player."""
564        # Refuse if the universal player already has a registered player from this domain.
565        # This prevents a second instance (e.g., two snapcast players on the same host)
566        # from replacing the first. The caller falls through to create a separate UP.
567        for link in universal_player.linked_output_protocols:
568            if link.protocol_domain == protocol_domain and self.get_player(link.output_protocol_id):
569                return
570
571        self._add_protocol_link(universal_player, protocol_player, protocol_domain)
572
573        # Check if linking actually succeeded (may be refused for duplicate domain)
574        if not protocol_player.protocol_parent_id:
575            return
576
577        if isinstance(universal_player, UniversalPlayer):
578            universal_player.add_protocol_player(protocol_player.player_id)
579            for conn_type, value in protocol_player.device_info.identifiers.items():
580                universal_player.device_info.add_identifier(conn_type, value)
581            # Update model/manufacturer if universal player has generic values
582            self._update_universal_device_info(universal_player, protocol_player)
583
584            # Persist all player data (protocol IDs, identifiers, device info) to config
585            for provider in self.mass.get_providers(ProviderType.PLAYER):
586                if provider.domain == "universal_player":
587                    await cast("UniversalPlayerProvider", provider)._save_player_data(
588                        universal_player.player_id, universal_player
589                    )
590                    break
591
592            # Check if this universal player should now be merged with another
593            self._check_merge_universal_players(universal_player)
594
595        protocol_player.refresh_state()
596        universal_player.refresh_state()
597
598    def _update_universal_device_info(
599        self, universal_player: UniversalPlayer, protocol_player: Player
600    ) -> None:
601        """
602        Update universal player's device info from protocol player if needed.
603
604        A universal player carries generic placeholder device info
605        (model="Universal Player", manufacturer="Music Assistant") when no real
606        values are known for it (yet). This method updates those values from a
607        protocol player that has real device info.
608        """
609        # Check if universal player has generic placeholder device info
610        device_info = universal_player.device_info
611        protocol_info = protocol_player.device_info
612
613        # Update model if universal player has generic value
614        if device_info.model in (None, "Universal Player") and protocol_info.model:
615            device_info.model = protocol_info.model
616
617        # Update manufacturer if universal player has generic value
618        if device_info.manufacturer in (None, "Music Assistant") and protocol_info.manufacturer:
619            device_info.manufacturer = protocol_info.manufacturer
620
621    def _save_universal_player_data(self, universal_player: UniversalPlayer) -> None:
622        """
623        Save universal player data to config via background task.
624
625        This is a helper to persist player data from synchronous code.
626        """
627
628        async def _do_save() -> None:
629            for provider in self.mass.get_providers(ProviderType.PLAYER):
630                if provider.domain == "universal_player":
631                    await cast("UniversalPlayerProvider", provider)._save_player_data(
632                        universal_player.player_id, universal_player
633                    )
634                    break
635
636        self.mass.create_task(_do_save())
637
638    def _get_known_protocol_ids(self, parent: Player) -> list[str]:
639        """
640        Get all protocol IDs tracked for a parent player.
641
642        Includes both active links and cached/inactive protocol IDs so callers can
643        safely migrate or clean up the full parent/protocol relationship.
644        """
645        result: list[str] = []
646        seen: set[str] = set()
647
648        for linked in parent.linked_output_protocols:
649            if linked.output_protocol_id not in seen:
650                result.append(linked.output_protocol_id)
651                seen.add(linked.output_protocol_id)
652
653        if parent.provider.domain == "universal_player" and isinstance(parent, UniversalPlayer):
654            cached_ids = parent._protocol_player_ids
655        else:
656            cached_ids = self._get_cached_protocol_ids(parent.player_id)
657
658        for protocol_id in cached_ids:
659            if protocol_id not in seen:
660                result.append(protocol_id)
661                seen.add(protocol_id)
662
663        return result
664
665    def _migrate_protocol_ids_to_parent(self, parent: Player, protocol_ids: set[str]) -> None:
666        """
667        Persist protocol ownership on a new parent without requiring active links.
668
669        This is used when protocol ownership moves from one parent to another during
670        promotion/merge flows. Active protocols are already linked in memory, but
671        disabled or temporarily unavailable protocols still need their cached parent
672        relationship moved as well.
673        """
674        if not protocol_ids:
675            return
676
677        if parent.provider.domain == "universal_player" and isinstance(parent, UniversalPlayer):
678            for protocol_id in protocol_ids:
679                parent.add_protocol_player(protocol_id)
680            self._save_universal_player_data(parent)
681        else:
682            conf_key = f"{CONF_PLAYERS}/{parent.player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
683            cached_ids = self._get_cached_protocol_ids(parent.player_id)
684            changed = False
685            for protocol_id in protocol_ids:
686                if protocol_id not in cached_ids:
687                    cached_ids.append(protocol_id)
688                    changed = True
689            if changed:
690                self.mass.config.set(conf_key, cached_ids)
691
692        for protocol_id in protocol_ids:
693            if self.mass.config.get(f"{CONF_PLAYERS}/{protocol_id}"):
694                self._save_protocol_parent_id(protocol_id, parent.player_id)
695
696    def _remove_protocol_ids_from_parent(self, parent: Player, protocol_ids: set[str]) -> None:
697        """
698        Remove protocol ownership from a parent before it is permanently cleaned up.
699
700        This prevents `_cleanup_protocol_links` from treating already-migrated
701        protocols as orphaned when the obsolete parent is unregistered.
702        """
703        if not protocol_ids:
704            return
705
706        remaining_links = [
707            link
708            for link in parent.linked_output_protocols
709            if link.output_protocol_id not in protocol_ids
710        ]
711        if len(remaining_links) != len(parent.linked_output_protocols):
712            parent.set_linked_output_protocols(remaining_links)
713
714        if parent.provider.domain == "universal_player" and isinstance(parent, UniversalPlayer):
715            for protocol_id in protocol_ids:
716                parent.remove_protocol_player(protocol_id)
717            if self.mass.config.get(f"{CONF_PLAYERS}/{parent.player_id}"):
718                self.mass.config.set(
719                    f"{CONF_PLAYERS}/{parent.player_id}/values/{CONF_LINKED_PROTOCOL_IDS}",
720                    parent._protocol_player_ids,
721                )
722        else:
723            for protocol_id in protocol_ids:
724                self._remove_protocol_id_from_cache(parent.player_id, protocol_id)
725
726    def _check_merge_universal_players(self, universal_player: UniversalPlayer) -> None:
727        """
728        Check if another universal player should be merged into this one.
729
730        Called after identifiers are copied from a protocol player to a universal player.
731        When a protocol player brings new identifiers (e.g., MAC from ARP enrichment),
732        the universal player may now match another universal player that was created
733        from a different protocol (e.g., DLNA-based universal player now matches
734        AirPlay-based universal player because they share the same MAC address).
735
736        The oldest universal player absorbs the other one. Only one merge is performed
737        per call; re-evaluation will catch cascading merges.
738        """
739        if not (match := self._find_mergeable_universal_player(universal_player)):
740            return
741        keep, remove = self._select_merge_winner(universal_player, match)
742        self.logger.info(
743            "Merging universal player %s into %s (shared identifiers)",
744            remove.player_id,
745            keep.player_id,
746        )
747        self._merge_universal_players(keep, remove)
748
749    def _find_mergeable_universal_player(
750        self, universal_player: UniversalPlayer
751    ) -> UniversalPlayer | None:
752        """
753        Return the first other universal player that represents the same device, if any.
754
755        Players that share a protocol domain are not returned: they are separate devices
756        that merely share an identifier, so merging them would orphan a protocol.
757
758        :param universal_player: The universal player to find a merge candidate for.
759        """
760        for player in list(self._players.values()):
761            if player.provider.domain != "universal_player":
762                continue
763            if player.player_id == universal_player.player_id:
764                continue
765            if not isinstance(player, UniversalPlayer):
766                continue
767
768            if not self._identifiers_match(universal_player, player, ""):
769                continue
770
771            # Do not merge if both UPs have protocols from the same domain.
772            # Multiple instances of the same protocol on one host (e.g., several
773            # squeezelite players on the same VM) are separate devices that happen
774            # to share an IP. Merging them would orphan one instance's protocol.
775            domains_a = {
776                link.protocol_domain
777                for link in universal_player.linked_output_protocols
778                if link.protocol_domain
779            }
780            domains_b = {
781                link.protocol_domain
782                for link in player.linked_output_protocols
783                if link.protocol_domain
784            }
785            if domains_a & domains_b:
786                self.logger.debug(
787                    "Skipping merge of %s and %s: shared protocol domain(s) %s",
788                    universal_player.player_id,
789                    player.player_id,
790                    domains_a & domains_b,
791                )
792                continue
793
794            return player
795
796        return None
797
798    def _select_merge_winner(
799        self, universal_player: UniversalPlayer, other_player: UniversalPlayer
800    ) -> tuple[UniversalPlayer, UniversalPlayer]:
801        """
802        Return which of the two universal players absorbs the other, as (keeper, absorbed).
803
804        The oldest player wins, on a tie the one with the most protocol links.
805
806        :param universal_player: The universal player the merge was triggered for.
807        :param other_player: The universal player it matched with.
808        """
809        # The outcome must be stable across server restarts. Without that, which
810        # UniversalPlayer "wins" depends on iteration order of self._players.values(),
811        # which can shift between runs and causes downstream player_id reshuffling
812        # (and broken entity bindings in consumers like the Home Assistant MA integration).
813        if self._merge_rank(universal_player) <= self._merge_rank(other_player):
814            return universal_player, other_player
815        return other_player, universal_player
816
817    def _merge_rank(self, universal_player: Player) -> tuple[int, int, str]:
818        """
819        Return the sort key of a universal player in a merge, lowest wins.
820
821        Age comes first because the keeper's player id is the one that survives, and the
822        oldest player is the one API consumers have been bound to the longest. The links
823        of the absorbed player move over either way, so nothing is lost by keeping the
824        smaller one. A player from before player ids were minted has no stored moment and
825        counts as the oldest, which is exactly what it is.
826        """
827        created_at = self.mass.config.get(
828            f"{CONF_PLAYERS}/{universal_player.player_id}/values/{CONF_CREATED_AT}", 0
829        )
830        return (
831            created_at if isinstance(created_at, int) else 0,
832            -len(universal_player.linked_output_protocols),
833            universal_player.player_id,
834        )
835
836    def _merge_universal_players(self, keep: UniversalPlayer, remove: UniversalPlayer) -> None:
837        """
838        Absorb one universal player into another and schedule the absorbed one's removal.
839
840        :param keep: The universal player that stays.
841        :param remove: The universal player that is absorbed.
842        """
843        known_protocol_ids = set(self._get_known_protocol_ids(remove))
844        active_protocol_ids = {link.output_protocol_id for link in remove.linked_output_protocols}
845        moved_protocol_ids: set[str] = set()
846
847        # Transfer protocol links from the removed player to the keeper
848        for linked in list(remove.linked_output_protocols):
849            if protocol_player := self.get_player(linked.output_protocol_id):
850                protocol_player.set_protocol_parent_id(None)
851                domain = linked.protocol_domain or protocol_player.provider.domain
852
853                # Check if keeper already has an active link from this domain
854                if self._parent_has_active_protocol_from_domain(keep, domain):
855                    self.logger.debug(
856                        "Skipping duplicate %s link during merge: %s",
857                        domain,
858                        linked.output_protocol_id,
859                    )
860                    continue
861
862                self._add_protocol_link(keep, protocol_player, domain)
863                if protocol_player.protocol_parent_id == keep.player_id:
864                    moved_protocol_ids.add(protocol_player.player_id)
865                    protocol_player.refresh_state()
866
867        # Move cached-only protocol ownership as well so old-parent cleanup
868        # does not wipe protocols that were intentionally preserved.
869        cached_only_ids = known_protocol_ids - active_protocol_ids
870        preserved_protocol_ids = moved_protocol_ids | cached_only_ids
871        self._migrate_protocol_ids_to_parent(keep, preserved_protocol_ids)
872        self._remove_protocol_ids_from_parent(remove, preserved_protocol_ids)
873
874        # Merge identifiers
875        for conn_type, value in remove.device_info.identifiers.items():
876            keep.device_info.add_identifier(conn_type, value)
877        keep.refresh_state()
878
879        # Persist updated data before the obsolete player is removed
880        self._save_universal_player_data(keep)
881
882        # Carry over the user's configuration and re-point group memberships
883        # before the permanent removal below deletes the losing wrapper's config
884        self._migrate_universal_player_config(remove.player_id, keep.player_id)
885        self._repoint_group_memberships(remove.player_id, keep.player_id)
886
887        # Stop playback and remove the obsolete player
888        self.mass.create_task(self._stop_and_unregister(remove))
889
890    def _link_protocols_to_universal(
891        self, universal_player: Player, protocol_players: list[Player]
892    ) -> None:
893        """Link protocol players to a universal player, cleaning up existing links."""
894        for player in protocol_players:
895            # Clean up if linked to another player
896            if player.protocol_parent_id:
897                if parent := self.get_player(player.protocol_parent_id):
898                    self._remove_protocol_link(parent, player.player_id)
899                player.set_protocol_parent_id(None)
900            # Link to universal player
901            self._add_protocol_link(universal_player, player, player.provider.domain)
902            player.refresh_state()
903
904        # Update availability from protocol players
905        universal_player.refresh_state()
906
907    async def _create_or_update_universal_player(self, protocol_players: list[Player]) -> None:
908        """
909        Create or update a UniversalPlayer for a set of protocol players.
910
911        Delegates to the universal player provider which handles orchestration,
912        locking, and player creation. The controller then links the protocols
913        to the universal player.
914        """
915        # Filter out players that got linked during the async delay
916        protocol_players = [p for p in protocol_players if not p.protocol_parent_id]
917        if not protocol_players:
918            return
919
920        # Get the universal_player provider
921        universal_provider: UniversalPlayerProvider | None = None
922        for provider in self.mass.get_providers(ProviderType.PLAYER):
923            if provider.domain == "universal_player":
924                universal_provider = cast("UniversalPlayerProvider", provider)
925                break
926
927        if not universal_provider:
928            return
929
930        # Delegate to provider - it handles locking, create/update decision, etc.
931        # It reports which universal player each protocol player belongs to, as a
932        # device with several instances of one protocol domain gets more than one.
933        assignments = await universal_provider.ensure_universal_players_for_protocols(
934            protocol_players
935        )
936
937        # Link the protocols to their universal player (the controller manages
938        # cross-provider state), skipping players that were linked in the meantime.
939        by_universal_player: dict[str, list[Player]] = {}
940        for player in protocol_players:
941            if player.protocol_parent_id:
942                continue
943            if universal_player := assignments.get(player.player_id):
944                by_universal_player.setdefault(universal_player.player_id, []).append(player)
945
946        for universal_player_id, players in by_universal_player.items():
947            if universal_player := self.get_player(universal_player_id):
948                self._link_protocols_to_universal(universal_player, players)
949
950    def _try_link_protocols_to_native(self, native_player: Player) -> None:
951        """Try to link protocol players to a native player."""
952        # First, check if there's a universal player for this device that should be replaced
953        self._check_replace_universal_player(native_player)
954
955        # Look for protocol players that should be linked
956        for protocol_player in self.all_players(return_protocol_players=True):
957            if protocol_player.state.type != PlayerType.PROTOCOL:
958                continue
959            if protocol_player.protocol_parent_id:
960                # Already linked to a parent (could be this native player after replacement)
961                continue
962            if protocol_player.underlying_player_id:
963                # Derived protocol players link via their underlying player instead
964                continue
965
966            protocol_domain = protocol_player.provider.domain
967
968            # Skip if this native player already has an active link from this domain
969            # (prevents a second instance of the same protocol from trying to link)
970            if self._parent_has_active_protocol_from_domain(native_player, protocol_domain):
971                continue
972
973            if self._identifiers_match(native_player, protocol_player, protocol_domain):
974                self._add_protocol_link(native_player, protocol_player, protocol_domain)
975                # Check if linking succeeded (may be refused for duplicate domain)
976                if protocol_player.protocol_parent_id is not None:
977                    protocol_player.refresh_state()
978                    native_player.refresh_state()
979
980        # Proactively recover disabled/missing protocols from config
981        # This ensures disabled protocols show up in the UI so they can be re-enabled
982        self._recover_cached_protocol_links(native_player)
983
984        # Second pass: match remaining unlinked protocol players via sibling identifiers.
985        # After cache recovery, the native player has linked protocols (e.g., AirPlay)
986        # whose identifiers can be used to match new protocol players (e.g., Sendspin bridge)
987        # that share the same device identifiers but couldn't match the native player directly.
988        for protocol_player in self.all_players(return_protocol_players=True):
989            if protocol_player.state.type != PlayerType.PROTOCOL:
990                continue
991            if protocol_player.protocol_parent_id:
992                continue
993            if protocol_player.underlying_player_id:
994                continue
995            protocol_domain = protocol_player.provider.domain
996            if self._parent_has_active_protocol_from_domain(native_player, protocol_domain):
997                continue
998            if self._match_via_linked_protocols(native_player, protocol_player, protocol_domain):
999                self.logger.debug(
1000                    "Linked %s to %s via sibling protocol identifiers",
1001                    protocol_player.player_id,
1002                    native_player.player_id,
1003                )
1004
1005        # Finally, link derived protocol players that ride directly on this
1006        # native player (derived players riding on the protocol players linked
1007        # above are handled by _add_protocol_link itself).
1008        self._link_derived_protocols_of(native_player)
1009
1010    def _check_replace_universal_player(self, native_player: Player) -> None:
1011        """Check if a universal player should be replaced by this native player."""
1012        # Skip if native_player is itself a universal player (prevent self-replacement)
1013        if native_player.provider.domain == "universal_player":
1014            return
1015
1016        # Look for universal players that match this native player
1017        for player in list(self._players.values()):
1018            if player.provider.domain != "universal_player":
1019                continue
1020
1021            # Check by identifiers first
1022            identifiers_match = self._identifiers_match(native_player, player, "")
1023
1024            # Also check if native player's ID is in the universal player's stored protocol list
1025            # This handles players that changed type (e.g., sendspin web players changed from
1026            # PROTOCOL to PLAYER type) and have no identifiers to match against
1027            player_id_in_protocols = (
1028                isinstance(player, UniversalPlayer)
1029                and native_player.player_id in player._protocol_player_ids
1030            )
1031
1032            if not identifiers_match and not player_id_in_protocols:
1033                continue
1034
1035            known_protocol_ids = set(self._get_known_protocol_ids(player))
1036            refused_protocol_ids: set[str] = set()
1037            moved_protocol_ids: set[str] = set()
1038
1039            # Transfer all protocol links from universal player to native player
1040            for linked in list(player.linked_output_protocols):
1041                if protocol_player := self.get_player(linked.output_protocol_id):
1042                    protocol_player.set_protocol_parent_id(None)
1043                    domain = linked.protocol_domain or protocol_player.provider.domain
1044                    self._add_protocol_link(native_player, protocol_player, domain)
1045                    if protocol_player.protocol_parent_id != native_player.player_id:
1046                        # Link refused, keep the protocol owned by the universal player.
1047                        protocol_player.set_protocol_parent_id(player.player_id)
1048                        refused_protocol_ids.add(protocol_player.player_id)
1049                        continue
1050                    protocol_player.refresh_state()
1051                    moved_protocol_ids.add(protocol_player.player_id)
1052
1053            # A refused link leaves the universal player in charge, so only hand over what
1054            # actually moved: ownership that exists in config alone stays with it, which
1055            # keeps a protocol derived from a refused one with the parent it will link to.
1056            migrated_protocol_ids = (
1057                moved_protocol_ids if refused_protocol_ids else known_protocol_ids
1058            )
1059            # A device that kept its id across a type change lists itself here.
1060            # It must never become its own protocol, and it must also be dropped
1061            # from the obsolete universal player so the permanent cleanup below
1062            # doesn't treat it as an orphaned protocol (which would re-wrap the
1063            # native player in a fresh universal player).
1064            migrated_protocol_ids.discard(native_player.player_id)
1065            self._migrate_protocol_ids_to_parent(native_player, migrated_protocol_ids)
1066            self._remove_protocol_ids_from_parent(
1067                player, migrated_protocol_ids | {native_player.player_id}
1068            )
1069            native_player.refresh_state()
1070
1071            if refused_protocol_ids:
1072                # Registered protocols that the native player refused remain on the wrapper.
1073                continue
1074
1075            # Carry over the user's configuration and re-point group memberships
1076            # before the permanent removal below deletes the universal player's config
1077            self._migrate_universal_player_config(player.player_id, native_player.player_id)
1078            self._repoint_group_memberships(player.player_id, native_player.player_id)
1079
1080            # Stop playback and remove the now-obsolete universal player
1081            self.mass.create_task(self._stop_and_unregister(player))
1082
1083    def _migrate_universal_player_config(self, universal_id: str, native_id: str) -> None:
1084        """
1085        Carry over user-set configuration from a replaced universal player.
1086
1087        Copies the custom display name, player config values, DSP settings and
1088        per-queue settings of the (obsolete) universal player onto the native
1089        player that replaces it, without overwriting values explicitly set on
1090        the native player itself. Must be called while the universal player's
1091        config still exists, as the permanent removal deletes it.
1092
1093        :param universal_id: Player id of the obsolete universal player being replaced.
1094        :param native_id: Player id of the native player that replaces it.
1095        """
1096        source_raw = self.mass.config.get(f"{CONF_PLAYERS}/{universal_id}")
1097        source_raw = source_raw if isinstance(source_raw, dict) else {}
1098        target_key = f"{CONF_PLAYERS}/{native_id}"
1099        target_raw = self.mass.config.get(target_key)
1100        target_raw = target_raw if isinstance(target_raw, dict) else {}
1101        player_config_changed = False
1102
1103        # only carry an actual user rename, not the auto-generated default name;
1104        # likewise a name on the native player only counts as a user override when
1105        # it differs from the default name
1106        custom_name = source_raw.get("name")
1107        target_name = target_raw.get("name")
1108        target_has_custom_name = bool(target_name) and target_name != target_raw.get("default_name")
1109        if (
1110            custom_name
1111            and custom_name != source_raw.get("default_name")
1112            and not target_has_custom_name
1113        ):
1114            self.mass.config.set(f"{target_key}/name", custom_name)
1115            player_config_changed = True
1116
1117        source_values = source_raw.get("values")
1118        source_values = source_values if isinstance(source_values, dict) else {}
1119        target_values = target_raw.get("values")
1120        target_values = target_values if isinstance(target_values, dict) else {}
1121        for key, value in source_values.items():
1122            if key in UNIVERSAL_PLAYER_INTERNAL_CONF_KEYS:
1123                continue
1124            if CONF_PROTOCOL_KEY_SPLITTER in key:
1125                # stale virtual mirror of a protocol player's own config
1126                continue
1127            if key in target_values:
1128                continue
1129            self.mass.config.set(f"{target_key}/values/{key}", deepcopy(value))
1130            player_config_changed = True
1131
1132        # DSP settings follow wholesale, unless the native player has its own
1133        dsp_changed = False
1134        source_dsp = self.mass.config.get(f"{CONF_PLAYER_DSP}/{universal_id}")
1135        if source_dsp and not self.mass.config.get(f"{CONF_PLAYER_DSP}/{native_id}"):
1136            self.mass.config.set(f"{CONF_PLAYER_DSP}/{native_id}", deepcopy(source_dsp))
1137            dsp_changed = True
1138
1139        queue_changed = self._migrate_universal_queue_config(universal_id, native_id)
1140
1141        if not (player_config_changed or dsp_changed or queue_changed):
1142            return
1143        self.logger.info(
1144            "Carried over configuration of universal player %s to %s", universal_id, native_id
1145        )
1146        if player_config_changed:
1147            # the native player's in-place config was loaded before the carry-over,
1148            # so reload it to make the migrated values (e.g. custom name) effective
1149            self.mass.create_task(self._reapply_player_config(native_id))
1150
1151    def _migrate_universal_queue_config(self, universal_id: str, native_id: str) -> bool:
1152        """
1153        Move the per-queue settings of a replaced universal player to its replacement.
1154
1155        Queue ids equal player ids, so the source entry is removed once it is carried over.
1156
1157        :param universal_id: Player id of the obsolete universal player.
1158        :param native_id: Player id of the native player that replaces it.
1159        :return: True if any queue setting was carried over.
1160        """
1161        queue_changed = False
1162        source_queue_raw = self.mass.config.get(f"{CONF_PLAYER_QUEUES}/{universal_id}")
1163        source_queue_raw = source_queue_raw if isinstance(source_queue_raw, dict) else None
1164        if source_queue_values := (source_queue_raw or {}).get("values"):
1165            target_queue_key = f"{CONF_PLAYER_QUEUES}/{native_id}"
1166            target_queue_raw = self.mass.config.get(target_queue_key)
1167            target_queue_raw = (
1168                deepcopy(target_queue_raw) if isinstance(target_queue_raw, dict) else {}
1169            )
1170            target_queue_values = target_queue_raw.setdefault("values", {})
1171            for key, value in source_queue_values.items():
1172                if key in target_queue_values:
1173                    continue
1174                target_queue_values[key] = deepcopy(value)
1175                queue_changed = True
1176            if queue_changed:
1177                target_queue_raw["queue_id"] = native_id
1178                self.mass.config.set(target_queue_key, target_queue_raw)
1179        if source_queue_raw is not None:
1180            self.mass.config.remove(f"{CONF_PLAYER_QUEUES}/{universal_id}")
1181        return queue_changed
1182
1183    async def _reapply_player_config(self, player_id: str) -> None:
1184        """Reload the stored config onto a registered player and refresh its state."""
1185        if not (player := self.get_player(player_id)):
1186            return
1187        config = await self.mass.config.get_player_config(player_id)
1188        player.set_config(config)
1189        player.update_state()
1190        self.mass.signal_event(EventType.PLAYER_CONFIG_UPDATED, object_id=player_id, data=config)
1191
1192    def _repoint_group_memberships(self, old_player_id: str, new_player_id: str) -> None:
1193        """
1194        Re-point group memberships from a removed player to its successor.
1195
1196        When a universal player is replaced by a native player or merged into
1197        another universal player, other players that list the removed player as
1198        a group member (or allowed member) must follow its successor so those
1199        memberships are not silently lost. Updates the persisted config and keeps
1200        any registered player whose membership changed in sync.
1201
1202        :param old_player_id: Player id that is being removed.
1203        :param new_player_id: Player id that replaces it.
1204        """
1205        all_player_configs = self.mass.config.get(CONF_PLAYERS, {})
1206        if not isinstance(all_player_configs, dict):
1207            return
1208        for other_id, other_cfg in all_player_configs.items():
1209            if not isinstance(other_cfg, dict):
1210                continue
1211            other_values = other_cfg.get("values")
1212            if not isinstance(other_values, dict):
1213                continue
1214            for key in (CONF_GROUP_MEMBERS, CONF_ALLOWED_MEMBERS):
1215                members = other_values.get(key)
1216                if not isinstance(members, list) or old_player_id not in members:
1217                    continue
1218                new_members: list[str] = []
1219                for member_id in members:
1220                    resolved = new_player_id if member_id == old_player_id else member_id
1221                    if resolved not in new_members:
1222                        new_members.append(resolved)
1223                self.mass.config.set(f"{CONF_PLAYERS}/{other_id}/values/{key}", new_members)
1224                # keep a registered player's in-place config copy and state in sync
1225                if other_player := self.get_player(other_id):
1226                    if entry := other_player.config.values.get(key):
1227                        entry.value = new_members
1228                    other_player.refresh_state()
1229
1230    async def _stop_and_unregister(self, player: Player) -> None:
1231        """
1232        Stop active playback on a player and then permanently unregister it.
1233
1234        Used when an obsolete universal player is replaced or merged away: while
1235        it is not idle its protocol child keeps playing the dead queue's stream
1236        until the buffer drains, so playback is stopped first. Queue ownership is
1237        intentionally not transferred.
1238
1239        :param player: The obsolete player to stop and permanently remove.
1240        """
1241        if player.playback_state != PlaybackState.IDLE:
1242            with suppress(PlayerCommandFailed, PlayerUnavailableError):
1243                await self.mass.player_queues.stop(player.player_id)
1244        await self.unregister(player.player_id, permanent=True)
1245
1246    def _parent_has_active_protocol_from_domain(
1247        self, parent: Player, domain: str, exclude_player_id: str | None = None
1248    ) -> bool:
1249        """
1250        Check if a parent already has an active (registered) protocol player from a given domain.
1251
1252        This prevents a second protocol player of the same domain (e.g., a second AirPlay
1253        instance on the same host) from replacing the first one's link on the same parent.
1254
1255        :param parent: The parent player to check.
1256        :param domain: The protocol domain to check for (e.g., "airplay", "dlna").
1257        :param exclude_player_id: Optional player ID to exclude from the check
1258            (used when checking if a player's own domain is already linked).
1259        """
1260        for link in parent.linked_output_protocols:
1261            if link.protocol_domain != domain:
1262                continue
1263            if exclude_player_id and link.output_protocol_id == exclude_player_id:
1264                continue
1265            # A registered player from this domain blocks the link, even if unavailable.
1266            # Being offline doesn't make it a different device — it's still occupying
1267            # this domain slot. The provider should remove stale players explicitly.
1268            if self.get_player(link.output_protocol_id):
1269                return True
1270        return False
1271
1272    def _add_protocol_link(
1273        self, native_player: Player, protocol_player: Player, protocol_domain: str
1274    ) -> None:
1275        """Add a protocol link from native player to protocol player."""
1276        # Never link a player to itself (hides it as its own protocol child).
1277        if native_player.player_id == protocol_player.player_id:
1278            return
1279        # Guard: refuse to replace an existing active link from the same domain.
1280        # This prevents a second instance of the same protocol (e.g., two AirPlay
1281        # instances on the same host) from silently replacing the first one.
1282        if self._parent_has_active_protocol_from_domain(
1283            native_player, protocol_domain, exclude_player_id=protocol_player.player_id
1284        ):
1285            self.logger.debug(
1286                "Refusing to link %s to %s: parent already has an active %s link",
1287                protocol_player.player_id,
1288                native_player.player_id,
1289                protocol_domain,
1290            )
1291            return
1292
1293        # Remove any existing link for the same protocol domain
1294        updated_protocols = [
1295            link
1296            for link in native_player.linked_output_protocols
1297            if link.protocol_domain != protocol_domain
1298        ]
1299
1300        # Get priority for this protocol
1301        priority = PROTOCOL_PRIORITY.get(protocol_domain, 100)
1302
1303        # Derived transports (e.g. a Sendspin bridge riding on an AirPlay player)
1304        # reference the base output they run on top of; "native" when they ride
1305        # on the parent player itself
1306        derived_from = protocol_player.underlying_player_id
1307        if derived_from == native_player.player_id:
1308            derived_from = "native"
1309
1310        # Add the new link
1311        updated_protocols.append(
1312            LinkedOutputProtocol(
1313                output_protocol_id=protocol_player.player_id,
1314                protocol_domain=protocol_domain,
1315                priority=priority,
1316                derived_from=derived_from,
1317            )
1318        )
1319        native_player.set_linked_output_protocols(updated_protocols)
1320
1321        # Set protocol player's parent
1322        protocol_player.set_protocol_parent_id(native_player.player_id)
1323
1324        # Persist linked protocol IDs to config for fast restart
1325        # (only for non-universal players, as universal players handle this themselves)
1326        if native_player.provider.domain != "universal_player":
1327            self._save_linked_protocol_ids(native_player)
1328        # Always save the parent ID on the protocol player for reverse lookup on restart
1329        # (needed for both native and universal parents to enable fast restore)
1330        self._save_protocol_parent_id(protocol_player.player_id, native_player.player_id)
1331
1332        # The freshly linked player may have derived protocol players (e.g. a
1333        # Sendspin bridge riding on it) waiting to join the same parent.
1334        self._link_derived_protocols_of(protocol_player)
1335
1336    def _remove_protocol_link(
1337        self, native_player: Player, protocol_player_id: str, permanent: bool = False
1338    ) -> None:
1339        """
1340        Remove a protocol link.
1341
1342        :param native_player: The parent player to remove the link from.
1343        :param protocol_player_id: The protocol player ID to unlink.
1344        :param permanent: If True, also removes the protocol ID from the cached list.
1345            Use this when the protocol player config is being deleted. If False,
1346            the protocol ID remains in the cache so it can be shown as disabled
1347            and re-enabled later.
1348        """
1349        updated_protocols = [
1350            link
1351            for link in native_player.linked_output_protocols
1352            if link.output_protocol_id != protocol_player_id
1353        ]
1354        native_player.set_linked_output_protocols(updated_protocols)
1355
1356        # Clear parent reference on protocol player if it still exists
1357        if protocol_player := self.get_player(protocol_player_id):
1358            if protocol_player.protocol_parent_id == native_player.player_id:
1359                protocol_player.set_protocol_parent_id(None)
1360
1361        # Update persisted linked protocol IDs
1362        if native_player.provider.domain != "universal_player":
1363            if permanent:
1364                # Permanently remove from cache (player config is being deleted)
1365                self._remove_protocol_id_from_cache(native_player.player_id, protocol_player_id)
1366            # Note: we don't call _save_linked_protocol_ids here anymore for non-permanent
1367            # removals because the merge approach will preserve the ID in the cache
1368        # Always clear the cached parent ID (for both native and universal parents)
1369        self._clear_protocol_parent_id(protocol_player_id)
1370
1371    def _save_linked_protocol_ids(self, native_player: Player) -> None:
1372        """
1373        Save linked protocol IDs to config for persistence across restarts.
1374
1375        This method merges active protocol IDs with existing cached IDs to preserve
1376        disabled protocol players in the cache. This allows disabled protocols to be
1377        shown in the UI so they can be re-enabled.
1378        """
1379        conf_key = f"{CONF_PLAYERS}/{native_player.player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1380        # Get existing cached IDs to preserve disabled protocols
1381        existing_ids: list[str] = self.mass.config.get(conf_key, [])
1382        # Get currently active protocol IDs
1383        active_ids = {link.output_protocol_id for link in native_player.linked_output_protocols}
1384        # Merge: keep existing IDs and add any new active ones
1385        merged_ids = list(existing_ids)
1386        for protocol_id in active_ids:
1387            if protocol_id not in merged_ids:
1388                merged_ids.append(protocol_id)
1389        self.mass.config.set(conf_key, merged_ids)
1390
1391    def _get_cached_protocol_ids(self, player_id: str) -> list[str]:
1392        """Get cached linked protocol IDs from config."""
1393        conf_key = f"{CONF_PLAYERS}/{player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1394        result = self.mass.config.get(conf_key, [])
1395        return list(result) if result else []
1396
1397    def _remove_protocol_id_from_cache(
1398        self, parent_player_id: str, protocol_player_id: str
1399    ) -> None:
1400        """
1401        Permanently remove a protocol player ID from the cached linked protocol IDs.
1402
1403        Use this when a protocol player config is being deleted, not just disabled.
1404        """
1405        conf_key = f"{CONF_PLAYERS}/{parent_player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1406        cached_ids: list[str] = self.mass.config.get(conf_key, [])
1407        if protocol_player_id in cached_ids:
1408            cached_ids.remove(protocol_player_id)
1409            self.mass.config.set(conf_key, cached_ids)
1410
1411    def _save_protocol_parent_id(self, protocol_player_id: str, parent_id: str) -> None:
1412        """Save the parent ID for a protocol player for persistence across restarts."""
1413        # Only save if the player config still exists to avoid creating partial entries
1414        if not self.mass.config.get(f"{CONF_PLAYERS}/{protocol_player_id}"):
1415            return
1416        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1417        self.mass.config.set(conf_key, parent_id)
1418
1419    def _save_underlying_player_id(self, player: Player) -> None:
1420        """
1421        Persist the derived-transport edge of a player to config.
1422
1423        Allows the edge to be resolved (e.g. by the config UI) even while the
1424        player is not registered. Clears a previously persisted edge when the
1425        player is no longer derived (e.g. a bridge client turned web player).
1426        """
1427        # Only save if the player config still exists to avoid creating partial entries
1428        if not self.mass.config.get(f"{CONF_PLAYERS}/{player.player_id}"):
1429            return
1430        conf_key = f"{CONF_PLAYERS}/{player.player_id}/values/{CONF_UNDERLYING_PLAYER_ID}"
1431        if player.underlying_player_id:
1432            self.mass.config.set(conf_key, player.underlying_player_id)
1433        elif self.mass.config.get(conf_key) is not None:
1434            self.mass.config.set(conf_key, None)
1435
1436    def _get_cached_protocol_parent_id(self, protocol_player_id: str) -> str | None:
1437        """Get cached parent ID for a protocol player from config."""
1438        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1439        result = self.mass.config.get(conf_key, None)
1440        return str(result) if result else None
1441
1442    def _clear_protocol_parent_id(self, protocol_player_id: str) -> None:
1443        """Clear the cached parent ID for a protocol player."""
1444        # Only clear if the player config still exists to avoid creating partial entries
1445        if not self.mass.config.get(f"{CONF_PLAYERS}/{protocol_player_id}"):
1446            return
1447        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1448        self.mass.config.set(conf_key, None)
1449
1450    def _recover_cached_protocol_links(self, native_player: Player) -> None:
1451        """
1452        Recover protocol links from config for disabled/missing protocols.
1453
1454        This ensures that disabled protocols show up in the output_protocols list
1455        so they can be re-enabled by the user. It also handles the case where
1456        protocol players haven't registered yet during startup.
1457        """
1458        # Get currently linked protocol IDs
1459        linked_protocol_ids = {
1460            link.output_protocol_id for link in native_player.linked_output_protocols
1461        }
1462
1463        # Get cached protocol IDs from config (includes protocols that were explicitly linked)
1464        cached_protocol_ids = self._get_cached_protocol_ids(native_player.player_id)
1465
1466        # Also check all protocol players that have protocol_parent_id pointing to this player
1467        # (this handles disabled protocols that may not be in linked_protocol_ids)
1468        all_player_configs = self.mass.config.get(CONF_PLAYERS, {})
1469        for protocol_id, protocol_config in all_player_configs.items():
1470            # Skip if not a protocol player
1471            if protocol_config.get("player_type") != "protocol":
1472                continue
1473            # Check if this protocol has a parent_id pointing to this native player
1474            protocol_values = protocol_config.get("values", {})
1475            protocol_parent_id = protocol_values.get(CONF_PROTOCOL_PARENT_ID)
1476            if protocol_parent_id == native_player.player_id:
1477                if protocol_id not in cached_protocol_ids:
1478                    cached_protocol_ids.append(protocol_id)
1479
1480        if not cached_protocol_ids:
1481            return
1482
1483        # Add link entries for any cached protocols that aren't currently linked
1484        updated_protocols = list(native_player.linked_output_protocols)
1485        for protocol_id in cached_protocol_ids:
1486            if protocol_id in linked_protocol_ids:
1487                continue  # Already linked
1488
1489            # Get protocol player config to determine the protocol domain
1490            protocol_config = self.mass.config.get(f"{CONF_PLAYERS}/{protocol_id}")
1491            if not protocol_config:
1492                continue
1493
1494            # Determine protocol domain from provider
1495            protocol_provider: str = protocol_config.get("provider")
1496            if not protocol_provider:
1497                continue
1498
1499            # Extract domain from provider instance_id (e.g., "airplay--uuid" -> "airplay")
1500            protocol_domain = protocol_provider.split("--", maxsplit=1)[0]
1501
1502            # Skip if parent already has a link from this domain
1503            existing_domains = {link.protocol_domain for link in updated_protocols}
1504            if protocol_domain in existing_domains:
1505                continue
1506
1507            # Get priority for this protocol
1508            priority = PROTOCOL_PRIORITY.get(protocol_domain, 100)
1509
1510            # Resolve the derived-transport edge from the live player when
1511            # registered, else from the persisted edge in config
1512            protocol_player = self.get_player(protocol_id)
1513            derived_from = (
1514                protocol_player.underlying_player_id
1515                if protocol_player
1516                else protocol_config.get("values", {}).get(CONF_UNDERLYING_PLAYER_ID)
1517            )
1518            if derived_from == native_player.player_id:
1519                derived_from = "native"
1520
1521            updated_protocols.append(
1522                LinkedOutputProtocol(
1523                    output_protocol_id=protocol_id,
1524                    protocol_domain=protocol_domain,
1525                    priority=priority,
1526                    derived_from=derived_from,
1527                )
1528            )
1529            self.logger.debug(
1530                "Recovered cached protocol link %s -> %s",
1531                native_player.player_id,
1532                protocol_id,
1533            )
1534
1535        if len(updated_protocols) != len(native_player.linked_output_protocols):
1536            native_player.set_linked_output_protocols(updated_protocols)
1537
1538    def _cleanup_protocol_links(self, player: Player) -> None:
1539        """Clean up protocol links when a player is permanently removed."""
1540        if player.state.type == PlayerType.PROTOCOL:
1541            # Protocol player being removed: remove link from parent
1542            if parent_id := player.protocol_parent_id:
1543                if parent_player := self.get_player(parent_id):
1544                    # Use permanent=True to also remove from cached protocol IDs
1545                    self._remove_protocol_link(parent_player, player.player_id, permanent=True)
1546                    if (
1547                        parent_player.provider.domain == "universal_player"
1548                        and len(parent_player.linked_output_protocols) == 0
1549                    ):
1550                        # No protocols left - the universal player has nothing to play
1551                        # on. Its config is deliberately kept: the player id is opaque
1552                        # and cannot be recreated, so deleting it here would orphan the
1553                        # entities API consumers bound to it. Only an explicit removal
1554                        # by the user deletes a universal player for good.
1555                        self.logger.info(
1556                            "Universal player %s has no protocols left",
1557                            parent_id,
1558                        )
1559                        self.mass.create_task(
1560                            self.mass.players.unregister(parent_id, permanent=False)
1561                        )
1562                    else:
1563                        parent_player.refresh_state()
1564                else:
1565                    # Parent not registered yet — still purge the cached id
1566                    self._remove_protocol_id_from_cache(parent_id, player.player_id)
1567        else:
1568            # Native/universal player being removed: handle all linked protocol players.
1569            # Collect all known protocol IDs from both active links and cached state,
1570            # since disabled/inactive protocols may only exist in the cached parent data.
1571            all_protocol_ids = set(self._get_known_protocol_ids(player))
1572            for protocol_id in all_protocol_ids:
1573                if protocol_player := self.get_player(protocol_id):
1574                    # Protocol player is available: clear parent and schedule re-evaluation
1575                    # so it can be matched to a new parent or a new universal player
1576                    self.logger.debug(
1577                        "Player %s removed - scheduling evaluation for protocol %s",
1578                        player.player_id,
1579                        protocol_id,
1580                    )
1581                    self._detach_protocol_child(protocol_player)
1582                else:
1583                    # Clear cached parent ID in config so protocol won't try to
1584                    # restore a link to the deleted player on next restart
1585                    self._clear_protocol_parent_id(protocol_id)
1586                    # Protocol player is not registered yet — it may still be
1587                    # mid-discovery (e.g., DLNA connecting via SSDP). Don't delete
1588                    # its config as that would cause a KeyError when it finishes
1589                    # registering. Stale configs are harmless and get cleaned up
1590                    # naturally on subsequent restarts.
1591                    self.logger.debug(
1592                        "Player %s removed - protocol %s not registered, skipping cleanup",
1593                        player.player_id,
1594                        protocol_id,
1595                    )
1596
1597    def _detach_protocol_children(self, parent_id: str) -> None:
1598        """
1599        Detach the registered protocol players of a parent player that is going away.
1600
1601        Covers the removal paths that don't unregister the parent first (e.g. its
1602        provider is unloaded), where the parent is not around anymore to enumerate
1603        its protocol players.
1604
1605        :param parent_id: Player id of the parent that is being removed.
1606        """
1607        for protocol_player in list(self._players.values()):
1608            if protocol_player.state.type != PlayerType.PROTOCOL:
1609                continue
1610            # a protocol player waiting for a parent that never registered only has
1611            # the link in its config, so fall back to the cached parent
1612            linked_parent_id = protocol_player.protocol_parent_id or (
1613                self._get_cached_protocol_parent_id(protocol_player.player_id)
1614            )
1615            if linked_parent_id != parent_id:
1616                continue
1617            self.logger.debug(
1618                "Player %s removed - scheduling evaluation for protocol %s",
1619                parent_id,
1620                protocol_player.player_id,
1621            )
1622            self._detach_protocol_child(protocol_player)
1623
1624    def _detach_protocol_child(self, protocol_player: Player) -> None:
1625        """Clear a protocol player's parent link and schedule a fresh evaluation."""
1626        self._clear_protocol_parent_id(protocol_player.player_id)
1627        protocol_player.set_protocol_parent_id(None)
1628        protocol_player.refresh_state()
1629        self._schedule_protocol_evaluation(protocol_player)
1630
1631    def _identifiers_match(
1632        self, player_a: Player, player_b: Player, protocol_domain: str = ""
1633    ) -> bool:
1634        """
1635        Check if identifiers match between two players.
1636
1637        Matching is done by comparing connection identifiers (MAC, serial, UUID).
1638        As a last resort, IP address is used when at least one player has a
1639        locally-administered MAC, indicating the device uses MAC randomization
1640        and ARP could not resolve the real hardware address.
1641
1642        Invalid identifiers (e.g., 00:00:00:00:00:00 MAC addresses) are filtered out
1643        to prevent false matches between unrelated devices.
1644        """
1645        identifiers_a = player_a.device_info.identifiers
1646        identifiers_b = player_b.device_info.identifiers
1647
1648        # Check identifiers in order of reliability
1649        # MAC_ADDRESS > SERIAL_NUMBER > UUID > CAST_UUID > AIRPLAY_ID
1650        for conn_type in (
1651            IdentifierType.MAC_ADDRESS,
1652            IdentifierType.SERIAL_NUMBER,
1653            IdentifierType.UUID,
1654            IdentifierType.CAST_UUID,
1655            IdentifierType.AIRPLAY_ID,
1656        ):
1657            val_a = identifiers_a.get(conn_type)
1658            val_b = identifiers_b.get(conn_type)
1659
1660            if not val_a or not val_b:
1661                continue
1662
1663            # Filter out invalid MAC addresses (00:00:00:00:00:00, ff:ff:ff:ff:ff:ff)
1664            if conn_type == IdentifierType.MAC_ADDRESS:
1665                if not is_valid_mac_address(val_a) or not is_valid_mac_address(val_b):
1666                    self.logger.log(
1667                        VERBOSE_LOG_LEVEL,
1668                        "Skipping invalid MAC address for matching: %s=%s, %s=%s",
1669                        player_a.display_name,
1670                        val_a,
1671                        player_b.display_name,
1672                        val_b,
1673                    )
1674                    continue
1675
1676            # Normalize values for comparison
1677            if conn_type == IdentifierType.MAC_ADDRESS:
1678                # Use MAC normalization that handles locally-administered bit differences
1679                # Some protocols (like AirPlay) report a locally-administered MAC variant
1680                # where bit 1 of the first octet is set (e.g., 54:78:... vs 56:78:...)
1681                val_a_norm = normalize_mac_for_matching(val_a)
1682                val_b_norm = normalize_mac_for_matching(val_b)
1683
1684                # Direct match on current MAC
1685                if val_a_norm == val_b_norm:
1686                    return True
1687
1688                # Multi-MAC matching: also check original reported MACs.
1689                # Devices with multiple interfaces (WiFi + Ethernet) may have ARP
1690                # resolve one MAC while the protocol reports a different one.
1691                macs_a = {val_a_norm}
1692                macs_b = {val_b_norm}
1693                reported_a = player_a.extra_data.get("reported_mac")
1694                reported_b = player_b.extra_data.get("reported_mac")
1695                if reported_a and is_valid_mac_address(reported_a):
1696                    macs_a.add(normalize_mac_for_matching(reported_a))
1697                if reported_b and is_valid_mac_address(reported_b):
1698                    macs_b.add(normalize_mac_for_matching(reported_b))
1699                if macs_a & macs_b:
1700                    return True
1701
1702                # No MAC match - continue to next identifier type
1703                continue
1704
1705            val_a_norm = val_a.lower().replace(":", "").replace("-", "")
1706            val_b_norm = val_b.lower().replace(":", "").replace("-", "")
1707
1708            # Direct match
1709            if val_a_norm == val_b_norm:
1710                return True
1711
1712            # Special case: Sonos UUID matching with DLNA _MR suffix
1713            # Sonos uses RINCON_xxx, DLNA uses RINCON_xxx_MR for Media Renderer
1714            if conn_type == IdentifierType.UUID:
1715                if val_b_norm.endswith("_mr") and val_b_norm[:-3] == val_a_norm:
1716                    return True
1717                if val_a_norm.endswith("_mr") and val_a_norm[:-3] == val_b_norm:
1718                    return True
1719
1720        # Last resort: IP-based matching.
1721        # Two players on the same IP are very likely the same physical device.
1722        # This handles two cases:
1723        # 1. MAC randomization: at least one player has no real MAC (LA or missing),
1724        #    so ARP couldn't resolve a usable address.
1725        # 2. Different MACs per protocol: some devices (e.g., Yamaha MusicCast) report
1726        #    different valid globally-unique MACs per protocol (DLNA vs AirPlay differ
1727        #    by 1 in the last octet). IP matching is safe here because two different
1728        #    devices on a LAN cannot share the same IP simultaneously.
1729        #    To avoid false positives between unrelated native players, this path
1730        #    requires at least one player to be a protocol or universal player.
1731        ip_a = identifiers_a.get(IdentifierType.IP_ADDRESS)
1732        ip_b = identifiers_b.get(IdentifierType.IP_ADDRESS)
1733        if ip_a and ip_b and ip_a == ip_b:
1734            mac_a = identifiers_a.get(IdentifierType.MAC_ADDRESS)
1735            mac_b = identifiers_b.get(IdentifierType.MAC_ADDRESS)
1736            a_is_real = (
1737                mac_a is not None
1738                and is_valid_mac_address(mac_a)
1739                and not is_locally_administered_mac(mac_a)
1740            )
1741            b_is_real = (
1742                mac_b is not None
1743                and is_valid_mac_address(mac_b)
1744                and not is_locally_administered_mac(mac_b)
1745            )
1746            # Case 1: at least one player has no real hardware MAC
1747            if not (a_is_real and b_is_real):
1748                return True
1749            # Case 2: both have real MACs but at least one is a protocol/universal player
1750            a_is_protocol = (
1751                player_a.type == PlayerType.PROTOCOL
1752                or player_a.provider.domain == "universal_player"
1753            )
1754            b_is_protocol = (
1755                player_b.type == PlayerType.PROTOCOL
1756                or player_b.provider.domain == "universal_player"
1757            )
1758            if a_is_protocol or b_is_protocol:
1759                return True
1760
1761        return False
1762
1763    def _select_best_output_protocol(self, player: Player) -> tuple[Player, OutputProtocol | None]:
1764        """
1765        Select the best available output protocol for a player.
1766
1767        Selection priority:
1768        1. Output protocol that is currently grouped/synced with other players.
1769        2. User's preferred output protocol (from player settings).
1770        3. Native playback (if player supports PLAY_MEDIA).
1771        4. The player's declared default output protocol domain, if available.
1772        5. Best available protocol by priority.
1773
1774        Returns tuple of (target_player, output_protocol).
1775        output_protocol is None when using native playback.
1776        """
1777        self.logger.log(
1778            VERBOSE_LOG_LEVEL,
1779            "Selecting output protocol for %s",
1780            player.state.name,
1781        )
1782
1783        # 1. Check if any output protocol is currently grouped
1784        for linked in player.linked_output_protocols:
1785            if protocol_player := self.get_player(linked.output_protocol_id):
1786                if protocol_player.available_for_playback and self._is_protocol_grouped(
1787                    protocol_player
1788                ):
1789                    self.logger.log(
1790                        VERBOSE_LOG_LEVEL,
1791                        "Selected protocol for %s: %s (grouped)",
1792                        player.state.name,
1793                        protocol_player.state.name,
1794                    )
1795                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1796
1797        # 2. Check for user's preferred output protocol.
1798        # The value is only stored while it differs from the entry's default: "native" when a
1799        # native output is available, otherwise "auto". A player without a native output (e.g. a
1800        # LinkPlay shell) therefore has no stored preference by default and gets its default
1801        # output domain applied in step 4.
1802        preferred = self.mass.config.get_raw_player_config_value(
1803            player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
1804        )
1805        if preferred and preferred != "auto":
1806            if preferred == "native":
1807                if PlayerFeature.PLAY_MEDIA in player.supported_features:
1808                    self.logger.log(
1809                        VERBOSE_LOG_LEVEL,
1810                        "Selected protocol for %s: native (user preference)",
1811                        player.state.name,
1812                    )
1813                    return player, None
1814            else:
1815                for linked in player.linked_output_protocols:
1816                    if linked.output_protocol_id == preferred:
1817                        if protocol_player := self.get_player(linked.output_protocol_id):
1818                            if protocol_player.available_for_playback:
1819                                self.logger.log(
1820                                    VERBOSE_LOG_LEVEL,
1821                                    "Selected protocol for %s: %s (user preference)",
1822                                    player.state.name,
1823                                    protocol_player.state.name,
1824                                )
1825                                return protocol_player, player.get_linked_protocol(
1826                                    linked.output_protocol_id
1827                                )
1828                        break
1829
1830        # 3. Use native playback if available
1831        if PlayerFeature.PLAY_MEDIA in player.supported_features:
1832            self.logger.log(
1833                VERBOSE_LOG_LEVEL, "Selected protocol for %s: native", player.state.name
1834            )
1835            return player, None
1836
1837        # 4. Use the player's preferred default protocol domain, if it declares one and a
1838        # matching linked protocol is available (e.g. a LinkPlay shell prefers DLNA). This
1839        # never influences grouping; it only steers the default output for playback. "Auto"
1840        # is the entry default here, so it consistently resolves to this domain default.
1841        if default_domain := player.default_output_protocol_domain:
1842            for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
1843                if linked.protocol_domain != default_domain:
1844                    continue
1845                if (protocol_player := self.get_player(linked.output_protocol_id)) and (
1846                    protocol_player.available_for_playback
1847                ):
1848                    self.logger.log(
1849                        VERBOSE_LOG_LEVEL,
1850                        "Selected protocol for %s: %s (default domain %s)",
1851                        player.state.name,
1852                        protocol_player.state.name,
1853                        default_domain,
1854                    )
1855                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1856
1857        # 5. Fall back to best protocol by priority
1858        for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
1859            if protocol_player := self.get_player(linked.output_protocol_id):
1860                if protocol_player.available_for_playback:
1861                    self.logger.log(
1862                        VERBOSE_LOG_LEVEL,
1863                        "Selected protocol for %s: %s (priority-based)",
1864                        player.state.name,
1865                        protocol_player.state.name,
1866                    )
1867                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1868
1869        raise PlayerCommandFailed(f"Player {player.state.name} has no available output protocols")
1870
1871    def _get_control_target(
1872        self,
1873        player: Player,
1874        required_feature: PlayerFeature,
1875        require_active: bool = False,
1876    ) -> Player | None:
1877        """
1878        Get the best player(protocol) to send audio-path commands to.
1879
1880        Resolves commands that travel with the audio (enqueue, pause, announcements),
1881        so the output that renders the audio outranks the native player. Volume and
1882        mute are control-plane instead and resolve through
1883        :meth:`Player._get_protocol_player_for_feature`, which orders differently.
1884
1885        :param player: The player the command was issued on.
1886        :param required_feature: The feature the resolved target has to support.
1887        :param require_active: Only accept the output that is already rendering,
1888            instead of falling back to an idle one.
1889        """
1890        # If we have an active protocol, use that
1891        if (
1892            player.active_output_protocol
1893            and player.active_output_protocol != "native"
1894            and (protocol_player := self.mass.players.get_player(player.active_output_protocol))
1895            and required_feature in protocol_player.supported_features
1896        ):
1897            return protocol_player
1898
1899        # if the player natively supports the required feature, use that
1900        if (
1901            player.active_output_protocol == "native"
1902            and required_feature in player.supported_features
1903        ):
1904            return player
1905
1906        # If require_active is set, and no active protocol found, return None
1907        if require_active:
1908            return None
1909
1910        # if the player natively supports the required feature, use that
1911        if required_feature in player.supported_features:
1912            return player
1913
1914        # An output the user explicitly picked owns the audio, so a command that has to
1915        # start playback on an idle player follows it rather than the priority below.
1916        # The stored value survives a relink, so it only counts while it still names one
1917        # of this player's own outputs.
1918        preferred = self.mass.config.get_raw_player_config_value(
1919            player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
1920        )
1921        if preferred and preferred not in ("auto", "native"):
1922            for linked in player.linked_output_protocols:
1923                if linked.output_protocol_id != preferred:
1924                    continue
1925                if (
1926                    (preferred_player := self.mass.players.get_player(str(preferred)))
1927                    and preferred_player.available_for_playback
1928                    and required_feature in preferred_player.supported_features
1929                ):
1930                    return preferred_player
1931                break
1932
1933        # Otherwise, use the best available linked protocol, ordered by the same
1934        # priority that regular playback selection applies.
1935        for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
1936            if (
1937                (protocol_player := self.mass.players.get_player(linked.output_protocol_id))
1938                and protocol_player.available_for_playback
1939                and required_feature in protocol_player.supported_features
1940            ):
1941                return protocol_player
1942
1943        return None
1944
1945    def _is_protocol_grouped(self, protocol_player: Player) -> bool:
1946        """
1947        Check if a protocol player is currently grouped/synced with other players.
1948
1949        Used to prefer protocols that are actively participating in a group,
1950        ensuring consistent playback across grouped players.
1951        """
1952        is_grouped = bool(
1953            protocol_player.state.synced_to
1954            or (
1955                protocol_player.state.group_members and len(protocol_player.state.group_members) > 1
1956            )
1957            or protocol_player.state.active_group
1958        )
1959        if is_grouped:
1960            self.logger.log(
1961                VERBOSE_LOG_LEVEL,
1962                "Protocol player %s is grouped",
1963                protocol_player.state.name,
1964            )
1965        return is_grouped
1966
1967    def _translate_members_to_remove_for_protocols(
1968        self,
1969        parent_player: Player,
1970        player_ids: list[str],
1971        parent_protocol_player: Player | None,
1972        parent_protocol_domain: str | None,
1973    ) -> tuple[list[str], list[str]]:
1974        """
1975        Translate member IDs to remove into protocol and native lists.
1976
1977        :param parent_player: The parent player to remove members from.
1978        :param player_ids: List of visible player IDs to remove.
1979        :param parent_protocol_player: The parent's protocol player if available.
1980        :param parent_protocol_domain: The parent's protocol domain if available.
1981        """
1982        self.logger.debug(
1983            "Translating members to remove for %s: player_ids=%s, parent_protocol_domain=%s",
1984            parent_player.state.name,
1985            player_ids,
1986            parent_protocol_domain,
1987        )
1988        protocol_members: list[str] = []
1989        native_members: list[str] = []
1990
1991        for child_player_id in player_ids:
1992            child_player = self.get_player(child_player_id)
1993            if not child_player:
1994                continue
1995
1996            # Check if this member is in the parent's group via protocol
1997            if parent_protocol_domain and parent_protocol_player:
1998                child_protocol = child_player.get_output_protocol_by_domain(parent_protocol_domain)
1999                if child_protocol and child_protocol.available:
2000                    # For native protocol players, use the child's player_id directly
2001                    child_protocol_id = (
2002                        child_player.player_id
2003                        if child_protocol.is_native
2004                        else child_protocol.output_protocol_id
2005                    )
2006                    if child_protocol_id in parent_protocol_player.group_members:
2007                        self.logger.debug(
2008                            "Translating removal: %s -> protocol %s",
2009                            child_player_id,
2010                            child_protocol_id,
2011                        )
2012                        protocol_members.append(child_protocol_id)
2013                        continue
2014
2015            # Check if child's protocol player is in parent's native group_members
2016            # This handles native protocol players (e.g., native AirPlay player like Apple TV)
2017            # where the parent itself contains protocol player IDs in its group_members
2018            translated = False
2019            for linked in child_player.linked_output_protocols:
2020                if linked.output_protocol_id in parent_player.group_members:
2021                    self.logger.debug(
2022                        "Translating removal (native parent): %s -> protocol %s",
2023                        child_player_id,
2024                        linked.output_protocol_id,
2025                    )
2026                    native_members.append(linked.output_protocol_id)
2027                    translated = True
2028                    break
2029
2030            if not translated:
2031                native_members.append(child_player_id)
2032
2033        return protocol_members, native_members
2034
2035    def _filter_protocol_members(self, member_ids: list[str], protocol_player: Player) -> list[str]:
2036        """Filter member IDs to only include players from the same protocol domain."""
2037        return [
2038            pid
2039            for pid in member_ids
2040            if (p := self.get_player(pid)) and p.provider.domain == protocol_player.provider.domain
2041        ]
2042
2043    def _filter_native_members(self, member_ids: list[str], parent_player: Player) -> list[str]:
2044        """Filter member IDs to only include players compatible with the parent."""
2045        return [
2046            pid
2047            for pid in member_ids
2048            if (p := self.get_player(pid))
2049            and (
2050                p.provider.instance_id == parent_player.provider.instance_id
2051                or pid in parent_player._attr_can_group_with
2052                or p.provider.instance_id in parent_player._attr_can_group_with
2053            )
2054        ]
2055
2056    def _try_child_preferred_protocol(
2057        self,
2058        child_player: Player,
2059        parent_player: Player,
2060    ) -> tuple[str | None, str | None]:
2061        """
2062        Try to use child's preferred output protocol for grouping.
2063
2064        Returns tuple of (child_protocol_id, protocol_domain) or (None, None).
2065        """
2066        child_preferred = self.mass.config.get_raw_player_config_value(
2067            child_player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
2068        )
2069        if not child_preferred or child_preferred in {"auto", "native"}:
2070            return None, None
2071
2072        # Find child's preferred protocol, with its current availability
2073        child_protocol = None
2074        for output_protocol in child_player.output_protocols:
2075            if output_protocol.output_protocol_id == child_preferred:
2076                child_protocol = output_protocol
2077                break
2078
2079        if not child_protocol or not child_protocol.available:
2080            return None, None
2081
2082        # Check if parent supports this protocol (including native protocol)
2083        parent_protocol = parent_player.get_output_protocol_by_domain(
2084            child_protocol.protocol_domain
2085        )
2086        if not parent_protocol or not parent_protocol.available:
2087            return None, None
2088
2089        # Check if this protocol supports set_members
2090        protocol_player = parent_player.get_protocol_player(parent_protocol.output_protocol_id)
2091        if (
2092            not protocol_player
2093            or PlayerFeature.SET_MEMBERS not in protocol_player.state.supported_features
2094        ):
2095            return None, None
2096
2097        return child_protocol.output_protocol_id, child_protocol.protocol_domain
2098
2099    def _can_use_native_grouping(
2100        self,
2101        child_player: Player,
2102        parent_player: Player,
2103        parent_supports_native: bool,
2104    ) -> bool:
2105        """Check if child can be grouped with parent using native grouping."""
2106        if not parent_supports_native:
2107            return False
2108        return (
2109            parent_player.is_native_group_compatible(child_player)
2110            or child_player.player_id in parent_player._attr_can_group_with
2111            or child_player.provider.instance_id in parent_player._attr_can_group_with
2112        )
2113
2114    def _try_find_common_protocol(
2115        self, child_player: Player, parent_player: Player
2116    ) -> tuple[OutputProtocol | None, OutputProtocol | None]:
2117        """
2118        Find common protocol that supports set_members.
2119
2120        Returns tuple of (parent_protocol, child_protocol) or (None, None).
2121        """
2122        for parent_output_protocol in parent_player.output_protocols:
2123            if not parent_output_protocol.available:
2124                continue
2125            child_protocol = child_player.get_output_protocol_by_domain(
2126                parent_output_protocol.protocol_domain
2127            )
2128            if not child_protocol or not child_protocol.available:
2129                continue
2130            protocol_player = parent_player.get_protocol_player(
2131                parent_output_protocol.output_protocol_id
2132            )
2133            if protocol_player and PlayerFeature.SET_MEMBERS in protocol_player.supported_features:
2134                return parent_output_protocol, child_protocol
2135        return None, None
2136
2137    def _parent_has_live_native_session(self, parent_player: Player) -> bool:
2138        """
2139        Return True when the parent currently holds a live native playback session.
2140
2141        The active output protocol lingers for a few seconds after stop, so a non-idle
2142        playback state is required to distinguish a real session from a just-stopped one.
2143        """
2144        return parent_player.active_output_protocol == "native" and (
2145            parent_player.state.playback_state in (PlaybackState.PLAYING, PlaybackState.PAUSED)
2146        )
2147
2148    def _order_members_for_native_join(
2149        self,
2150        player_ids: list[str],
2151        parent_player: Player,
2152        parent_supports_native_grouping: bool,
2153    ) -> list[str]:
2154        """
2155        Order members so a live native session can be joined without splitting the group.
2156
2157        When the parent already holds a live native session, children that cannot group
2158        natively are evaluated first: they may force a shared protocol for the whole group,
2159        and processing them before the native-capable children lets those join that same
2160        protocol instead of being stranded in a separate native sub-group. The order is left
2161        untouched when the parent is not playing natively, so fresh-group selection is unchanged.
2162
2163        :param player_ids: The member IDs to be added, in their original order.
2164        :param parent_player: The parent player being joined.
2165        :param parent_supports_native_grouping: Whether the parent can group natively.
2166        """
2167        if not self._parent_has_live_native_session(parent_player):
2168            return player_ids
2169        return sorted(
2170            player_ids,
2171            key=lambda pid: bool(
2172                (child := self.get_player(pid))
2173                and self._can_use_native_grouping(
2174                    child, parent_player, parent_supports_native_grouping
2175                )
2176            ),
2177        )
2178
2179    def _try_join_active_native_session(
2180        self,
2181        child_player: Player,
2182        parent_player: Player,
2183        parent_protocol_domain: str | None,
2184        parent_supports_native_grouping: bool,
2185        native_members: list[str],
2186    ) -> bool:
2187        """
2188        Add the child to native_members if it can join the parent's active native session.
2189
2190        A child's preferred output protocol must only steer protocol selection when the child
2191        initiates its own playback; when it joins a parent that is already playing natively it
2192        should adopt native grouping if compatible, rather than forcing the whole group onto
2193        the child's preferred protocol. Skipped once a protocol has been selected for the group,
2194        so mixed batches stay cohesive on a single protocol.
2195
2196        :param child_player: The player being added to the group.
2197        :param parent_player: The parent player being joined.
2198        :param parent_protocol_domain: The protocol domain already selected for the group, if any.
2199        :param parent_supports_native_grouping: Whether the parent can group natively.
2200        :param native_members: The native members list to append to when the child joins.
2201        """
2202        if not (
2203            self._parent_has_live_native_session(parent_player)
2204            and not parent_protocol_domain
2205            and self._can_use_native_grouping(
2206                child_player, parent_player, parent_supports_native_grouping
2207            )
2208        ):
2209            return False
2210        native_members.append(child_player.player_id)
2211        self.logger.log(
2212            VERBOSE_LOG_LEVEL,
2213            "Joining parent's active native session for %s",
2214            child_player.state.name,
2215        )
2216        return True
2217
2218    def _translate_native_members_to_protocol(
2219        self, parent_player: Player, protocol_domain: str, member_ids: list[str]
2220    ) -> list[str]:
2221        """
2222        Translate natively grouped members onto the protocol domain the parent plays through.
2223
2224        Members that do not have that protocol cannot follow the parent at all and are
2225        dropped with a warning instead.
2226
2227        :param parent_player: The parent player the members are grouped with.
2228        :param protocol_domain: The protocol domain selected for the group.
2229        :param member_ids: The member IDs that were selected for native grouping.
2230        """
2231        translated: list[str] = []
2232        for member_id in member_ids:
2233            member_player = self.get_player(member_id)
2234            if not member_player:
2235                continue
2236            # a native group's members may be listed by their protocol player id
2237            if member_player.protocol_parent_id:
2238                member_player = self.get_player(member_player.protocol_parent_id) or member_player
2239            member_protocol = member_player.get_output_protocol_by_domain(protocol_domain)
2240            if not member_protocol or not member_protocol.available:
2241                self.logger.warning(
2242                    "Cannot group %s with %s: the group plays through the %s protocol, "
2243                    "which %s does not support",
2244                    member_player.state.name,
2245                    parent_player.state.name,
2246                    protocol_domain,
2247                    member_player.state.name,
2248                )
2249                continue
2250            # For native protocol players, use the member's player_id directly
2251            translated.append(
2252                member_player.player_id
2253                if member_protocol.is_native
2254                else member_protocol.output_protocol_id
2255            )
2256            self.logger.log(
2257                VERBOSE_LOG_LEVEL,
2258                "Moving %s from native grouping to the %s protocol",
2259                member_player.state.name,
2260                protocol_domain,
2261            )
2262        return translated
2263
2264    def _move_native_members_to_group_protocol(
2265        self,
2266        parent_player: Player,
2267        parent_protocol_player: Player | None,
2268        parent_protocol_domain: str | None,
2269        protocol_members: list[str],
2270        native_members: list[str],
2271    ) -> None:
2272        """
2273        Move the members selected for native grouping onto the protocol the group ended up on.
2274
2275        Does nothing unless the group ends up on one of the parent's protocols while the
2276        parent's native grouping needs the parent's own stream: only then do those members
2277        have no session left to attach to.
2278
2279        :param parent_player: The parent player being joined.
2280        :param parent_protocol_player: The protocol player selected for the group, if any.
2281        :param parent_protocol_domain: The protocol domain selected for the group, if any.
2282        :param protocol_members: The protocol member list the translated IDs are added to.
2283        :param native_members: The native member IDs, emptied when they are moved over.
2284        """
2285        if not (
2286            native_members
2287            and parent_protocol_domain
2288            and parent_protocol_player
2289            and parent_protocol_player.player_id != parent_player.player_id
2290            and parent_player.native_grouping_requires_own_stream
2291        ):
2292            return
2293        protocol_members.extend(
2294            self._translate_native_members_to_protocol(
2295                parent_player, parent_protocol_domain, native_members
2296            )
2297        )
2298        native_members.clear()
2299
2300    def _migrate_stranded_native_members(
2301        self,
2302        parent_player: Player,
2303        parent_protocol_player: Player,
2304        protocol_members: list[str],
2305    ) -> list[str]:
2306        """
2307        Move the native members that a switch to the given protocol strands onto that protocol.
2308
2309        Returns the member IDs that are still attached to the parent's own stream, so the
2310        caller can release them from it. Empty unless the parent renders that stream itself
2311        while its native grouping attaches the members to exactly that stream: only then are
2312        they left without anything to play.
2313
2314        :param parent_player: The parent player that is about to switch protocol.
2315        :param parent_protocol_player: The protocol player the parent will render through.
2316        :param protocol_members: The protocol member list the translated IDs are added to.
2317        """
2318        if parent_protocol_player.player_id == parent_player.player_id:
2319            return []
2320        if not parent_player.native_grouping_requires_own_stream:
2321            return []
2322        if parent_player.active_output_protocol not in (None, "native"):
2323            return []
2324        if parent_player.state.playback_state not in (PlaybackState.PLAYING, PlaybackState.PAUSED):
2325            return []
2326        stranded = [
2327            member_id
2328            for member_id in parent_player.group_members
2329            if member_id != parent_player.player_id
2330        ]
2331        for protocol_id in self._translate_native_members_to_protocol(
2332            parent_player, parent_protocol_player.provider.domain, stranded
2333        ):
2334            if protocol_id not in protocol_members:
2335                protocol_members.append(protocol_id)
2336        return stranded
2337
2338    async def _stop_native_session(
2339        self,
2340        parent_player: Player,
2341        parent_protocol_player: Player,
2342        stranded_native_members: list[str],
2343    ) -> None:
2344        """
2345        Release the given members from the parent's own stream and stop it.
2346
2347        :param parent_player: The parent player whose native session is handed over.
2348        :param parent_protocol_player: The protocol player taking the output over.
2349        :param stranded_native_members: The members to release, already migrated.
2350        """
2351        self.logger.debug(
2352            "Stopping the native session of %s before switching to %s, migrated members: %s",
2353            parent_player.state.name,
2354            parent_protocol_player.state.name,
2355            stranded_native_members,
2356        )
2357        # The members already joined the protocol group, so the native session only has to
2358        # release them and stop. Releasing them first also clears the native group, which
2359        # keeps a later native playback command from resurrecting it. Both calls take the
2360        # provider's own lock, so they must run one after the other.
2361        await parent_player.set_members(player_ids_to_remove=stranded_native_members)
2362        await parent_player.stop()
2363
2364    def _translate_members_for_protocols(
2365        self,
2366        parent_player: Player,
2367        player_ids: list[str],
2368        parent_protocol_player: Player | None,
2369        parent_protocol_domain: str | None,
2370    ) -> tuple[list[str], list[str], Player | None, str | None]:
2371        """
2372        Translate member IDs to protocol or native IDs.
2373
2374        The grouping method is picked per member, see _select_grouping_for_member.
2375
2376        Returns tuple of (protocol_members, native_members, protocol_player, protocol_domain).
2377        """
2378        protocol_members: list[str] = []
2379        native_members: list[str] = []
2380        parent_supports_native_grouping = (
2381            PlayerFeature.SET_MEMBERS in parent_player.supported_features
2382        )
2383        player_ids = self._order_members_for_native_join(
2384            player_ids, parent_player, parent_supports_native_grouping
2385        )
2386
2387        self.logger.log(
2388            VERBOSE_LOG_LEVEL,
2389            "Translating members for %s: parent_supports_native=%s, parent_protocol=%s (%s)",
2390            parent_player.state.name,
2391            parent_supports_native_grouping,
2392            parent_protocol_player.state.name if parent_protocol_player else "none",
2393            parent_protocol_domain or "none",
2394        )
2395
2396        for child_player_id in player_ids:
2397            child_player = self.get_player(child_player_id)
2398            if not child_player:
2399                continue
2400
2401            self.logger.log(
2402                VERBOSE_LOG_LEVEL,
2403                "Processing child %s (type=%s, protocols=%s)",
2404                child_player.state.name,
2405                child_player.state.type,
2406                [p.protocol_domain for p in child_player.output_protocols],
2407            )
2408
2409            parent_protocol_player, parent_protocol_domain = self._select_grouping_for_member(
2410                child_player,
2411                parent_player,
2412                parent_protocol_player,
2413                parent_protocol_domain,
2414                parent_supports_native_grouping,
2415                protocol_members,
2416                native_members,
2417            )
2418
2419        # Post-pass: the protocol selected for the group is only known once every child has
2420        # been processed, so the members picked for native grouping are corrected here.
2421        self._move_native_members_to_group_protocol(
2422            parent_player,
2423            parent_protocol_player,
2424            parent_protocol_domain,
2425            protocol_members,
2426            native_members,
2427        )
2428
2429        return protocol_members, native_members, parent_protocol_player, parent_protocol_domain
2430
2431    def _select_grouping_for_member(
2432        self,
2433        child_player: Player,
2434        parent_player: Player,
2435        parent_protocol_player: Player | None,
2436        parent_protocol_domain: str | None,
2437        parent_supports_native_grouping: bool,
2438        protocol_members: list[str],
2439        native_members: list[str],
2440    ) -> tuple[Player | None, str | None]:
2441        """
2442        Pick the grouping method for a single member and add it to the matching member list.
2443
2444        Selection priority when grouping:
2445        0. If the parent is already playing natively and the child can be grouped
2446           natively, join that native session (a child joining an existing group must
2447           not force the whole group onto its own preferred output protocol)
2448        1. Try child's preferred output protocol (from player settings)
2449        2. Try parent's active output protocol (if any and child supports it)
2450        3. Try native grouping (if parent and child are compatible)
2451        4. Search for common protocol that supports set_members
2452        5. Log warning if no option works
2453
2454        Returns the protocol player/domain the group is on, which the picked method may have
2455        changed.
2456
2457        :param child_player: The player being added to the group.
2458        :param parent_player: The parent player being joined.
2459        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2460        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2461        :param parent_supports_native_grouping: Whether the parent can group natively.
2462        :param protocol_members: The protocol member list to append to.
2463        :param native_members: The native member list to append to.
2464        """
2465        # Priority 0: The parent is already playing natively and the child can join
2466        # that native session directly - adopt it before considering the child's own
2467        # preferred output protocol.
2468        if self._try_join_active_native_session(
2469            child_player,
2470            parent_player,
2471            parent_protocol_domain,
2472            parent_supports_native_grouping,
2473            native_members,
2474        ):
2475            return parent_protocol_player, parent_protocol_domain
2476
2477        # Priority 0.5: a player that runs its own multiroom (e.g. a LinkPlay control shell)
2478        # keeps grouping on its native path rather than routing it through a linked protocol
2479        # that is merely its preferred playback output. Native compatibility still decides
2480        # whether this is possible, so an incompatible/cross-backend pair falls through.
2481        if child_player.prefer_native_grouping and self._can_use_native_grouping(
2482            child_player, parent_player, parent_supports_native_grouping
2483        ):
2484            native_members.append(child_player.player_id)
2485            self.logger.log(
2486                VERBOSE_LOG_LEVEL,
2487                "Using native grouping (preferred) for %s",
2488                child_player.state.name,
2489            )
2490            return parent_protocol_player, parent_protocol_domain
2491
2492        # Priority 1: the child's preferred output protocol
2493        grouped, parent_protocol_player, parent_protocol_domain = (
2494            self._try_group_via_preferred_protocol(
2495                child_player,
2496                parent_player,
2497                parent_protocol_player,
2498                parent_protocol_domain,
2499                protocol_members,
2500            )
2501        )
2502        if grouped:
2503            return parent_protocol_player, parent_protocol_domain
2504
2505        # Priority 2: the protocol the group is already on
2506        grouped, parent_protocol_player, parent_protocol_domain = (
2507            self._try_group_via_active_protocol(
2508                child_player,
2509                parent_protocol_player,
2510                parent_protocol_domain,
2511                protocol_members,
2512            )
2513        )
2514        if grouped:
2515            return parent_protocol_player, parent_protocol_domain
2516
2517        # Priority 3: native grouping
2518        if self._can_use_native_grouping(
2519            child_player, parent_player, parent_supports_native_grouping
2520        ):
2521            native_members.append(child_player.player_id)
2522            self.logger.log(
2523                VERBOSE_LOG_LEVEL,
2524                "Using native grouping for %s",
2525                child_player.state.name,
2526            )
2527            return parent_protocol_player, parent_protocol_domain
2528
2529        # Priority 4: a protocol both players share that supports set_members
2530        grouped, parent_protocol_player, parent_protocol_domain = (
2531            self._try_group_via_common_protocol(
2532                child_player,
2533                parent_player,
2534                parent_protocol_player,
2535                parent_protocol_domain,
2536                protocol_members,
2537            )
2538        )
2539        if grouped:
2540            return parent_protocol_player, parent_protocol_domain
2541
2542        # Priority 5: no option worked
2543        self.logger.warning(
2544            "Cannot group %s with %s: no compatible grouping method found "
2545            "(tried: child preferred protocol, parent active protocol, "
2546            "native grouping, common protocols)",
2547            child_player.state.name,
2548            parent_player.state.name,
2549        )
2550        return parent_protocol_player, parent_protocol_domain
2551
2552    def _try_group_via_preferred_protocol(
2553        self,
2554        child_player: Player,
2555        parent_player: Player,
2556        parent_protocol_player: Player | None,
2557        parent_protocol_domain: str | None,
2558        protocol_members: list[str],
2559    ) -> tuple[bool, Player | None, str | None]:
2560        """
2561        Try to group the child through the output protocol it prefers in its player settings.
2562
2563        Only used when the group is not on a protocol yet or is already on that same protocol.
2564        Returns whether the child was grouped, together with the protocol player/domain the
2565        group is on: the child's preferred protocol may become the group's protocol.
2566
2567        :param child_player: The player being added to the group.
2568        :param parent_player: The parent player being joined.
2569        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2570        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2571        :param protocol_members: The protocol member list to append to.
2572        """
2573        child_protocol_id, protocol_domain = self._try_child_preferred_protocol(
2574            child_player, parent_player
2575        )
2576        if not (
2577            child_protocol_id
2578            and protocol_domain
2579            and (not parent_protocol_domain or protocol_domain == parent_protocol_domain)
2580        ):
2581            return False, parent_protocol_player, parent_protocol_domain
2582
2583        if not parent_protocol_player or parent_protocol_domain != protocol_domain:
2584            parent_protocol = parent_player.get_output_protocol_by_domain(protocol_domain)
2585            if parent_protocol:
2586                parent_protocol_player = parent_player.get_protocol_player(
2587                    parent_protocol.output_protocol_id
2588                )
2589                parent_protocol_domain = protocol_domain
2590        protocol_members.append(child_protocol_id)
2591        self.logger.log(
2592            VERBOSE_LOG_LEVEL,
2593            "Using child's preferred protocol %s for %s",
2594            protocol_domain,
2595            child_player.state.name,
2596        )
2597        return True, parent_protocol_player, parent_protocol_domain
2598
2599    def _try_group_via_active_protocol(
2600        self,
2601        child_player: Player,
2602        parent_protocol_player: Player | None,
2603        parent_protocol_domain: str | None,
2604        protocol_members: list[str],
2605    ) -> tuple[bool, Player | None, str | None]:
2606        """
2607        Try to group the child through the protocol the group is already on.
2608
2609        Returns whether the child was grouped, together with the protocol player/domain the
2610        group is on: the selection is dropped when that protocol cannot group members itself,
2611        so a later grouping method can select another one.
2612
2613        :param child_player: The player being added to the group.
2614        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2615        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2616        :param protocol_members: The protocol member list to append to.
2617        """
2618        if not parent_protocol_domain or not parent_protocol_player:
2619            return False, parent_protocol_player, parent_protocol_domain
2620
2621        if PlayerFeature.SET_MEMBERS not in parent_protocol_player.state.supported_features:
2622            self.logger.log(
2623                VERBOSE_LOG_LEVEL,
2624                "Parent's active protocol %s does not support SET_MEMBERS, "
2625                "will search for alternative",
2626                parent_protocol_domain,
2627            )
2628            # Drop the selection so a later grouping method can select a new protocol
2629            return False, None, None
2630
2631        child_protocol = child_player.get_output_protocol_by_domain(parent_protocol_domain)
2632        if not child_protocol or not child_protocol.available:
2633            return False, parent_protocol_player, parent_protocol_domain
2634
2635        # For native protocol players, use the child's player_id directly
2636        # (e.g., a native sendspin web player IS the protocol player)
2637        child_protocol_id = (
2638            child_player.player_id
2639            if child_protocol.is_native
2640            else child_protocol.output_protocol_id
2641        )
2642        protocol_members.append(child_protocol_id)
2643        self.logger.log(
2644            VERBOSE_LOG_LEVEL,
2645            "Using parent's active protocol %s for %s",
2646            parent_protocol_domain,
2647            child_player.state.name,
2648        )
2649        return True, parent_protocol_player, parent_protocol_domain
2650
2651    def _try_group_via_common_protocol(
2652        self,
2653        child_player: Player,
2654        parent_player: Player,
2655        parent_protocol_player: Player | None,
2656        parent_protocol_domain: str | None,
2657        protocol_members: list[str],
2658    ) -> tuple[bool, Player | None, str | None]:
2659        """
2660        Try to group the child through a protocol both players share.
2661
2662        Returns whether the child was grouped, together with the protocol player/domain the
2663        group is on: the shared protocol may become the group's protocol.
2664
2665        :param child_player: The player being added to the group.
2666        :param parent_player: The parent player being joined.
2667        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2668        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2669        :param protocol_members: The protocol member list to append to.
2670        """
2671        parent_protocol, child_protocol = self._try_find_common_protocol(
2672            child_player, parent_player
2673        )
2674        if not parent_protocol or not child_protocol:
2675            return False, parent_protocol_player, parent_protocol_domain
2676
2677        if not parent_protocol_player or parent_protocol_domain != parent_protocol.protocol_domain:
2678            parent_protocol_player = parent_player.get_protocol_player(
2679                parent_protocol.output_protocol_id
2680            )
2681            if parent_protocol_player:
2682                parent_protocol_domain = parent_protocol_player.provider.domain
2683        # For native protocol players, use the child's player_id directly
2684        child_protocol_id = (
2685            child_player.player_id
2686            if child_protocol.is_native
2687            else child_protocol.output_protocol_id
2688        )
2689        protocol_members.append(child_protocol_id)
2690        self.logger.log(
2691            VERBOSE_LOG_LEVEL,
2692            "Selected common protocol %s for grouping %s with %s",
2693            parent_protocol.protocol_domain,
2694            child_player.state.name,
2695            parent_player.state.name,
2696        )
2697        return True, parent_protocol_player, parent_protocol_domain
2698
2699    async def _forward_protocol_set_members(
2700        self,
2701        parent_player: Player,
2702        parent_protocol_player: Player,
2703        protocol_members_to_add: list[str],
2704        protocol_members_to_remove: list[str],
2705    ) -> None:
2706        """
2707        Forward protocol members to protocol player's set_members and manage active output protocol.
2708
2709        :param parent_player: The parent player (native/universal).
2710        :param parent_protocol_player: The protocol player to forward commands to.
2711        :param protocol_members_to_add: Protocol player IDs to add.
2712        :param protocol_members_to_remove: Protocol player IDs to remove.
2713        """
2714        filtered_protocol_add = self._filter_protocol_members(
2715            protocol_members_to_add, parent_protocol_player
2716        )
2717        filtered_protocol_remove = self._filter_protocol_members(
2718            protocol_members_to_remove, parent_protocol_player
2719        )
2720        self.logger.debug(
2721            "Protocol grouping on %s: filtered_add=%s, filtered_remove=%s",
2722            parent_protocol_player.state.name,
2723            filtered_protocol_add,
2724            filtered_protocol_remove,
2725        )
2726
2727        if not filtered_protocol_add and not filtered_protocol_remove:
2728            return
2729
2730        # Safety check: verify protocol player supports SET_MEMBERS
2731        if PlayerFeature.SET_MEMBERS not in parent_protocol_player.state.supported_features:
2732            self.logger.error(
2733                "Protocol player %s does not support SET_MEMBERS, cannot perform grouping. "
2734                "This should have been caught earlier in the flow.",
2735                parent_protocol_player.state.name,
2736            )
2737            return
2738
2739        # Members that ride the parent's own stream are stranded by the protocol switch below,
2740        # so they join the protocol group in this very same call and their native session is
2741        # torn down afterwards.
2742        stranded_native_members = (
2743            self._migrate_stranded_native_members(
2744                parent_player, parent_protocol_player, filtered_protocol_add
2745            )
2746            if filtered_protocol_add
2747            else []
2748        )
2749
2750        # This runs before set_members because a member's own stream starts inside that call
2751        # and the provider resolves the member's volume control as it starts: unless its parent
2752        # already points at this protocol, that resolution picks a sibling interface of the same
2753        # device (e.g. its cast side) over the one carrying the audio.
2754        self._activate_protocol_on_added_children(filtered_protocol_add)
2755
2756        self.logger.debug(
2757            "Calling set_members on protocol player %s with add=%s, remove=%s",
2758            parent_protocol_player.state.name,
2759            filtered_protocol_add,
2760            filtered_protocol_remove,
2761        )
2762        await parent_protocol_player.set_members(
2763            player_ids_to_add=filtered_protocol_add or None,
2764            player_ids_to_remove=filtered_protocol_remove or None,
2765        )
2766
2767        if filtered_protocol_add:
2768            await self._activate_group_output_protocol(
2769                parent_player, parent_protocol_player, stranded_native_members
2770            )
2771
2772        self.logger.debug(
2773            "After set_members, protocol player %s state: group_members=%s, synced_to=%s",
2774            parent_protocol_player.state.name,
2775            parent_protocol_player.group_members,
2776            parent_protocol_player.synced_to,
2777        )
2778
2779    def _activate_protocol_on_added_children(self, protocol_member_ids: list[str]) -> None:
2780        """
2781        Point the parent of each given protocol member at the protocol carrying the group audio.
2782
2783        :param protocol_member_ids: The protocol player IDs joining the group.
2784        """
2785        for child_protocol_id in protocol_member_ids:
2786            if not (child_protocol := self.get_player(child_protocol_id)):
2787                continue
2788            if not child_protocol.protocol_parent_id:
2789                continue
2790            if not (child_player := self.get_player(child_protocol.protocol_parent_id)):
2791                continue
2792            if child_player.active_output_protocol == child_protocol_id:
2793                continue
2794            self.logger.debug(
2795                "Setting active output protocol on child %s to %s",
2796                child_player.state.name,
2797                child_protocol_id,
2798            )
2799            child_player.set_active_output_protocol(child_protocol_id)
2800
2801    async def _activate_group_output_protocol(
2802        self,
2803        parent_player: Player,
2804        parent_protocol_player: Player,
2805        stranded_native_members: list[str],
2806    ) -> None:
2807        """
2808        Mark the given protocol as the parent's output and hand the playback over to it.
2809
2810        The handover only runs when the parent is actually switching protocol while it is
2811        rendering; playback is resumed only for a parent that was playing, so adding a member
2812        never starts playback on its own.
2813
2814        :param parent_player: The parent player that just gained protocol members.
2815        :param parent_protocol_player: The protocol player the members joined.
2816        :param stranded_native_members: The members left without a stream by the switch.
2817        """
2818        previous_protocol = parent_player.active_output_protocol
2819        was_playing = parent_player.state.playback_state == PlaybackState.PLAYING
2820        # A paused player still holds its output, so the handover has to run for it too.
2821        was_rendering = was_playing or parent_player.state.playback_state == PlaybackState.PAUSED
2822
2823        # Native protocol: parent_protocol_player is the same as parent_player
2824        is_native_protocol = parent_protocol_player.player_id == parent_player.player_id
2825        already_using_native = previous_protocol in (None, "native")
2826        already_using_this_protocol = previous_protocol == parent_protocol_player.player_id
2827        switching_protocols = not (
2828            (is_native_protocol and already_using_native) or already_using_this_protocol
2829        )
2830
2831        self.logger.debug(
2832            "Protocol grouping: is_native=%s, already_native=%s, already_this=%s, "
2833            "switching=%s, was_rendering=%s",
2834            is_native_protocol,
2835            already_using_native,
2836            already_using_this_protocol,
2837            switching_protocols,
2838            was_rendering,
2839        )
2840
2841        if not (is_native_protocol and already_using_native):
2842            parent_player.set_active_output_protocol(parent_protocol_player.player_id)
2843
2844        if not (was_rendering and switching_protocols):
2845            return
2846
2847        self.logger.info(
2848            "Handing the output of %s over to the %s protocol%s",
2849            parent_player.state.name,
2850            parent_protocol_player.provider.domain,
2851            " and resuming playback" if was_playing else "",
2852        )
2853        if stranded_native_members:
2854            await self._stop_native_session(
2855                parent_player, parent_protocol_player, stranded_native_members
2856            )
2857        old_parent_members = await self._stop_previous_protocol(
2858            parent_player, parent_protocol_player, previous_protocol
2859        )
2860        if was_playing:
2861            await self.mass.players.cmd_resume(parent_player.player_id)
2862        if old_parent_members:
2863            self.logger.debug(
2864                "Re-adding migrated members %s to %s on new protocol",
2865                old_parent_members,
2866                parent_player.state.name,
2867            )
2868            # Use internal handler because we are already inside a
2869            # _handle_set_members call chain that holds the play lock.
2870            await self.mass.players._handle_set_members(
2871                parent_player,
2872                player_ids_to_add=old_parent_members,
2873            )
2874
2875    async def _stop_previous_protocol(
2876        self,
2877        parent_player: Player,
2878        parent_protocol_player: Player,
2879        previous_protocol: str | None,
2880    ) -> list[str]:
2881        """
2882        Stop the protocol player the parent was rendering through and return its members.
2883
2884        The returned IDs are parent player IDs, so the caller can re-add them to the group
2885        once the new protocol carries the audio. Empty if there is nothing to hand over.
2886
2887        :param parent_player: The parent player that is switching protocol.
2888        :param parent_protocol_player: The protocol player taking the output over.
2889        :param previous_protocol: The parent's previous active output protocol, if any.
2890        """
2891        if previous_protocol in (None, "native"):
2892            return []
2893        if not (old_protocol_player := self.get_player(previous_protocol)):
2894            return []
2895        if old_protocol_player.player_id == parent_protocol_player.player_id:
2896            return []
2897        # Translate the old protocol's child members back to parent player IDs
2898        old_parent_members: list[str] = []
2899        for member_id in old_protocol_player.group_members:
2900            if member_id == old_protocol_player.player_id:
2901                continue
2902            if not (member_player := self.get_player(member_id)):
2903                continue
2904            parent_id = member_player.protocol_parent_id or member_id
2905            if parent_id != parent_player.player_id:
2906                old_parent_members.append(parent_id)
2907        self.logger.debug(
2908            "Stopping old protocol player %s before switching to %s, migrating members: %s",
2909            old_protocol_player.state.name,
2910            parent_protocol_player.state.name,
2911            old_parent_members,
2912        )
2913        # Use internal handler to stop the specific protocol player,
2914        # bypassing group/sync redirect and queue redirect logic.
2915        await self.mass.players._handle_cmd_stop(old_protocol_player.player_id)
2916        return old_parent_members
2917