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,
122            player_id: str,
123            permanent: bool = False,
124            replacement_player_id: str | None = None,
125        ) -> Coroutine[Any, Any, None]: ...
126
127    def _is_protocol_player(self, player: Player) -> bool:
128        """
129        Check if a player is a generic protocol player without native support.
130
131        Protocol players have PlayerType.PROTOCOL set by their provider, indicating
132        they are generic streaming endpoints (e.g., AirPlay receiver, Chromecast device)
133        without vendor-specific native support in Music Assistant.
134        """
135        return player.state.type == PlayerType.PROTOCOL
136
137    def _evaluate_protocol_links(self, player: Player) -> None:
138        """
139        Evaluate and establish protocol links for a player.
140
141        Called when a player is registered to:
142        1. If it's from a protocol provider - try to link to a native player.
143        2. If it's a native player - try to link any existing protocol players.
144        """
145        if player.state.type == PlayerType.PROTOCOL:
146            # Protocol player: try to find a native parent
147            self._try_link_protocol_to_native(player)
148        elif player.state.type == PlayerType.GROUP:
149            return
150        else:
151            # A player that registers with a non-protocol type can no longer be a
152            # protocol child: drop a leftover persisted parent link (e.g. from a
153            # bridge client that turned web player) so the startup repair pass
154            # doesn't heal its player type back to protocol.
155            if self._get_cached_protocol_parent_id(player.player_id):
156                self._clear_protocol_parent_id(player.player_id)
157            # Native player (including STEREO_PAIR): try to find protocol players to link
158            self._try_link_protocols_to_native(player)
159
160    def _try_link_protocol_to_native(self, protocol_player: Player) -> None:
161        """Try to link a protocol player to a native player."""
162        protocol_domain = protocol_player.provider.domain
163
164        # Derived protocol players (e.g. Sendspin bridges riding on another
165        # protocol) resolve strictly via their underlying player - no identifier
166        # matching or delayed evaluation. If the underlying player has no parent
167        # yet, the link is established by _link_derived_protocols_of as soon as
168        # the underlying player gets linked.
169        if protocol_player.underlying_player_id:
170            self._try_link_derived_protocol(protocol_player)
171            return
172
173        # Check for cached parent_id from previous session and restore link immediately
174        cached_parent_id = self._get_cached_protocol_parent_id(protocol_player.player_id)
175        if cached_parent_id:
176            result = self._try_restore_cached_parent(
177                protocol_player, cached_parent_id, protocol_domain
178            )
179            if result:
180                return
181            # Link was refused or parent has active domain - fall through to search
182
183        # Look for a matching native player
184        if self._try_link_to_existing_player(protocol_player, protocol_domain):
185            return
186
187        # No native player found - schedule delayed evaluation to allow other protocols to register
188        if not protocol_player.protocol_parent_id:
189            self._schedule_protocol_evaluation(protocol_player)
190
191    def _try_restore_cached_parent(
192        self, protocol_player: Player, cached_parent_id: str, protocol_domain: str
193    ) -> bool:
194        """
195        Try to restore a cached parent link from a previous session.
196
197        :param protocol_player: The protocol player to link.
198        :param cached_parent_id: The cached parent player ID.
199        :param protocol_domain: The protocol domain (e.g., "airplay").
200        :return: True if handled (linked or waiting), False if should fall through.
201        """
202        if parent_player := self.get_player(cached_parent_id):
203            if parent_player.state.type == PlayerType.GROUP:
204                self._clear_protocol_parent_id(protocol_player.player_id)
205                return False
206            already_linked = any(
207                link.output_protocol_id == protocol_player.player_id
208                for link in parent_player.linked_output_protocols
209            )
210            if already_linked:
211                # Already linked from a previous call - just restore parent and identifiers
212                protocol_player.set_protocol_parent_id(cached_parent_id)
213            else:
214                # Try to add the link (may be refused if domain already has active link)
215                self._add_protocol_link(parent_player, protocol_player, protocol_domain)
216            if protocol_player.protocol_parent_id:
217                protocol_player.refresh_state()
218                parent_player.refresh_state()
219                # Merge the protocol player's identifiers into the universal player
220                # so identifiers discovered since the last persist (e.g. an
221                # ARP-resolved MAC) are included and new protocol players
222                # (like Sendspin bridges) can match via identifiers.
223                if parent_player.provider.domain == "universal_player" and isinstance(
224                    parent_player, UniversalPlayer
225                ):
226                    for conn_type, value in protocol_player.device_info.identifiers.items():
227                        parent_player.device_info.add_identifier(conn_type, value)
228                    self._update_universal_device_info(parent_player, protocol_player)
229                    # Check if this universal player should now be merged with another
230                    # (e.g., DLNA brought a MAC via ARP that matches an AirPlay universal)
231                    self._check_merge_universal_players(parent_player)
232                return True
233            # Link was refused (domain already active on parent) - fall through
234            return False
235
236        # Parent is not registered yet. Leave the protocol player unparented
237        # so the caller schedules delayed evaluation, which can wait for the
238        # cached parent without stranding the protocol player on a dangling id.
239        return False
240
241    def _try_link_to_existing_player(self, protocol_player: Player, protocol_domain: str) -> bool:
242        """
243        Try to link a protocol player to an existing native or universal player.
244
245        :param protocol_player: The protocol player to link.
246        :param protocol_domain: The protocol domain (e.g., "airplay").
247        :return: True if linked successfully, False if no match found.
248        """
249        # Protocol players should only link to:
250        # 1. True native players (Sonos, etc.)
251        # 2. Universal players
252        # NOT to other protocol players (they get merged via universal_player)
253        for native_player in self.all_players(return_protocol_players=False):
254            if native_player.player_id == protocol_player.player_id:
255                continue
256            if native_player.state.type in (PlayerType.PROTOCOL, PlayerType.GROUP):
257                continue
258
259            # For universal players, check if this protocol player is in its stored list
260            # or if identifiers match (for new protocol players like Sendspin bridges
261            # that weren't previously known to the Universal Player)
262            if native_player.provider.domain == "universal_player":
263                if isinstance(native_player, UniversalPlayer):
264                    is_known = protocol_player.player_id in native_player._protocol_player_ids
265                    is_match = not is_known and self._identifiers_match(
266                        native_player, protocol_player, protocol_domain
267                    )
268                    if is_known or is_match:
269                        self._add_protocol_link(native_player, protocol_player, protocol_domain)
270                        # Check if linking actually succeeded (may be refused for
271                        # duplicate domain)
272                        if not protocol_player.protocol_parent_id:
273                            continue
274                        # Merge the protocol player's identifiers into the universal
275                        # player so newly discovered identifiers are included as well
276                        for conn_type, value in protocol_player.device_info.identifiers.items():
277                            native_player.device_info.add_identifier(conn_type, value)
278                        # Update model/manufacturer if universal player has generic values
279                        self._update_universal_device_info(native_player, protocol_player)
280                        # Register newly matched protocol player with the universal player
281                        if is_match:
282                            native_player.add_protocol_player(protocol_player.player_id)
283                        # Persist updated data to config (async via task)
284                        self._save_universal_player_data(native_player)
285                        # Check if this universal player should now be merged with another
286                        self._check_merge_universal_players(native_player)
287                        protocol_player.refresh_state()
288                        native_player.refresh_state()
289                        return True
290                continue
291
292            # Check cached protocol IDs first for fast matching on restart
293            cached_ids = self._get_cached_protocol_ids(native_player.player_id)
294            if protocol_player.player_id in cached_ids:
295                self._add_protocol_link(native_player, protocol_player, protocol_domain)
296                if protocol_player.protocol_parent_id:
297                    protocol_player.refresh_state()
298                    native_player.refresh_state()
299                    return True
300                # Link refused (domain duplicate) - try next native player
301                continue
302
303            # Fallback to identifier matching
304            if self._identifiers_match(native_player, protocol_player, protocol_domain):
305                self._add_protocol_link(native_player, protocol_player, protocol_domain)
306                if protocol_player.protocol_parent_id:
307                    protocol_player.refresh_state()
308                    native_player.refresh_state()
309                    return True
310                # Link refused (domain duplicate) - try next native player
311                continue
312
313            # Final fallback: check if any already-linked protocol player on this native
314            # player shares identifiers with the new protocol player ("sibling matching").
315            # This handles native players (e.g., HEOS) that don't have their own MAC/serial
316            # identifiers but have protocol players (e.g., AirPlay) from the same device
317            # that do share identifiers with the new protocol player (e.g., Sendspin bridge).
318            if self._match_via_linked_protocols(native_player, protocol_player, protocol_domain):
319                return True
320
321        return False
322
323    def _match_via_linked_protocols(
324        self,
325        native_player: Player,
326        protocol_player: Player,
327        protocol_domain: str,
328    ) -> bool:
329        """
330        Try to match a protocol player to a native player via sibling protocol identifiers.
331
332        Check if any of the native player's already-linked protocol players share
333        identifiers with the new protocol player. This handles native players that lack
334        their own device identifiers but have sibling protocols from the same physical device.
335
336        :param native_player: The native player to potentially link to.
337        :param protocol_player: The new protocol player to link.
338        :param protocol_domain: The protocol domain of the new player.
339        :return: True if linked successfully, False if no match found.
340        """
341        for linked in native_player.linked_output_protocols:
342            linked_player = self.get_player(linked.output_protocol_id)
343            if not linked_player:
344                continue
345            if self._identifiers_match(linked_player, protocol_player, protocol_domain):
346                self._add_protocol_link(native_player, protocol_player, protocol_domain)
347                if protocol_player.protocol_parent_id:
348                    protocol_player.refresh_state()
349                    native_player.refresh_state()
350                    return True
351                # Link refused (domain duplicate) - stop checking siblings
352                break
353        return False
354
355    def _try_link_derived_protocol(self, protocol_player: Player) -> bool:
356        """
357        Link a derived protocol player to the parent of its underlying player.
358
359        Derived protocol players carry an underlying_player_id declared by their
360        bridge, which makes the parent resolution deterministic: they always join
361        the parent of the player they ride on (or that player itself when it is
362        not a protocol player). Callers must ensure the player is not linked yet.
363
364        :param protocol_player: The derived protocol player to link.
365        :return: True if the player got linked, False if the underlying player
366            (or its parent) is not available yet or the link was refused.
367        """
368        underlying = self.get_player(protocol_player.underlying_player_id or "")
369        if underlying is None:
370            return False
371        if underlying.state.type == PlayerType.PROTOCOL:
372            parent = (
373                self.get_player(underlying.protocol_parent_id)
374                if underlying.protocol_parent_id
375                else None
376            )
377        else:
378            parent = underlying
379        if parent is None or parent.state.type == PlayerType.GROUP:
380            return False
381
382        self._add_protocol_link(parent, protocol_player, protocol_player.provider.domain)
383        if not protocol_player.protocol_parent_id:
384            # Link refused (e.g. parent already has an active link from this domain)
385            return False
386
387        if parent.provider.domain == "universal_player" and isinstance(parent, UniversalPlayer):
388            # Track membership and identifiers on the universal player so the
389            # derived protocol restores quickly on the next start.
390            parent.add_protocol_player(protocol_player.player_id)
391            for conn_type, value in protocol_player.device_info.identifiers.items():
392                parent.device_info.add_identifier(conn_type, value)
393            self._save_universal_player_data(parent)
394
395        protocol_player.refresh_state()
396        parent.refresh_state()
397        self.logger.debug(
398            "Linked derived protocol %s to %s (via underlying %s)",
399            protocol_player.player_id,
400            parent.player_id,
401            underlying.player_id,
402        )
403        return True
404
405    def _link_derived_protocols_of(self, underlying_player: Player) -> None:
406        """
407        Link any waiting derived protocol players that ride on the given player.
408
409        Called after a player is linked to a parent (or registered as a native
410        player), so derived protocol players that registered earlier can join
411        the same parent.
412        """
413        for candidate in self.all_players(return_protocol_players=True):
414            if candidate.underlying_player_id != underlying_player.player_id:
415                continue
416            if candidate.protocol_parent_id:
417                continue
418            self._try_link_derived_protocol(candidate)
419
420    def _schedule_protocol_evaluation(self, protocol_player: Player) -> None:
421        """
422        Schedule a delayed protocol evaluation.
423
424        Delays evaluation to allow other protocol players and native players to register.
425        Uses a longer delay (30s) if this protocol player was previously linked to a native
426        player that hasn't registered yet, giving native providers time to start up.
427        """
428        player_id = protocol_player.player_id
429
430        # Cancel any existing pending evaluation for this player
431        if player_id in self._pending_protocol_evaluations:
432            self._pending_protocol_evaluations[player_id].cancel()
433
434        # Check if this protocol player has a cached parent (was previously linked)
435        cached_parent_id = self._get_cached_protocol_parent_id(player_id)
436        if cached_parent_id and not self.get_player(cached_parent_id):
437            # Previously linked to a native player that hasn't registered yet
438            # Use longer delay to give native providers time to start up
439            delay = 45.0
440            self.logger.debug(
441                "Protocol player %s waiting for cached parent %s (45s delay)",
442                player_id,
443                cached_parent_id,
444            )
445        else:
446            # Standard delay for protocol player discovery
447            # Allows time for other protocols and native players to register
448            delay = 15.0
449
450        # Schedule evaluation after the delay
451        handle = self.mass.loop.call_later(
452            delay,
453            lambda: self.mass.create_task(self._delayed_protocol_evaluation(player_id)),
454        )
455        self._pending_protocol_evaluations[player_id] = handle
456
457    async def _delayed_protocol_evaluation(self, player_id: str) -> None:
458        """
459        Perform delayed protocol evaluation.
460
461        Called after a delay to allow all protocol players for a device to register.
462        Decides whether to create a universal player, join an existing one, or
463        promote a single protocol player directly.
464
465        Uses a shared lock to serialize evaluations - multiple protocol players from the
466        same device may trigger concurrent evaluations that would otherwise race each other.
467        """
468        self._pending_protocol_evaluations.pop(player_id, None)
469
470        async with self._delayed_evaluation_lock:
471            protocol_player = self.get_player(player_id)
472            if not protocol_player or protocol_player.protocol_parent_id:
473                return
474            if protocol_player.state.type != PlayerType.PROTOCOL:
475                # The player changed type while the evaluation was pending
476                # (e.g. re-registered as a regular player); it must never be
477                # linked as a protocol or wrapped in a universal player.
478                return
479
480            # Derived protocol players resolve strictly via their underlying
481            # player and never match by identifiers or wrap into universal
482            # players; they wait for _link_derived_protocols_of otherwise.
483            if protocol_player.underlying_player_id:
484                self._try_link_derived_protocol(protocol_player)
485                return
486
487            protocol_domain = protocol_player.provider.domain
488
489            # Re-try linking to an existing native/universal player
490            if self._try_link_to_existing_player(protocol_player, protocol_domain):
491                return
492
493            # Check if there's an existing universal player we should join
494            if existing_universal := self._find_matching_universal_player(protocol_player):
495                await self._add_protocol_to_existing_universal(
496                    existing_universal, protocol_player, protocol_domain
497                )
498                if protocol_player.protocol_parent_id is not None:
499                    return
500                # Link refused (domain duplicate) - fall through to create separate UP
501
502            # Refuse to create a universal player wrapper when the cached parent
503            # config exists but is disabled. The user explicitly turned the
504            # parent device off; surfacing its protocols as a separate player
505            # would defeat that intent.
506            cached_parent_id = self._get_cached_protocol_parent_id(player_id)
507            if cached_parent_id:
508                parent_raw = self.mass.config.get(f"{CONF_PLAYERS}/{cached_parent_id}")
509                if parent_raw and not parent_raw.get("enabled", True):
510                    self.logger.debug(
511                        "Skipping universal player creation for %s: cached parent %s is disabled",
512                        player_id,
513                        cached_parent_id,
514                    )
515                    return
516
517            # Find all protocol players that match this device's identifiers
518            matching_protocols = self._find_matching_protocol_players(protocol_player)
519
520            # Create or update UniversalPlayer for all protocol players
521            await self._create_or_update_universal_player(matching_protocols)
522
523    def _find_matching_protocol_players(self, protocol_player: Player) -> list[Player]:
524        """
525        Find all protocol players that match the same device as the given player.
526
527        Searches through all registered protocol players to find ones that share
528        identifiers (MAC, IP, UUID) with the given player, indicating they represent
529        the same physical device.
530        """
531        matching = [protocol_player]
532        protocol_domain = protocol_player.provider.domain
533
534        for other_player in self.all_players(return_protocol_players=True):
535            if other_player.player_id == protocol_player.player_id:
536                continue
537            if other_player.state.type != PlayerType.PROTOCOL:
538                continue
539            if other_player.protocol_parent_id:
540                continue
541            if other_player.underlying_player_id:
542                # Derived protocol players follow their underlying player
543                # once it is linked; they never seed a universal player.
544                continue
545            # Skip players from the same protocol domain
546            # Multiple instances of the same protocol on one host are separate players
547            if other_player.provider.domain == protocol_domain:
548                continue
549            if self._identifiers_match(protocol_player, other_player):
550                matching.append(other_player)
551
552        return matching
553
554    def _find_matching_universal_player(self, protocol_player: Player) -> Player | None:
555        """Find an existing universal player that matches this protocol player."""
556        for player in self._players.values():
557            if not isinstance(player, UniversalPlayer):
558                continue
559            if self._identifiers_match(protocol_player, player, ""):
560                return player
561        return None
562
563    async def _add_protocol_to_existing_universal(
564        self, universal_player: Player, protocol_player: Player, protocol_domain: str
565    ) -> None:
566        """Add a protocol player to an existing universal player."""
567        # Refuse if the universal player already has a registered player from this domain.
568        # This prevents a second instance (e.g., two snapcast players on the same host)
569        # from replacing the first. The caller falls through to create a separate UP.
570        for link in universal_player.linked_output_protocols:
571            if link.protocol_domain == protocol_domain and self.get_player(link.output_protocol_id):
572                return
573
574        self._add_protocol_link(universal_player, protocol_player, protocol_domain)
575
576        # Check if linking actually succeeded (may be refused for duplicate domain)
577        if not protocol_player.protocol_parent_id:
578            return
579
580        if isinstance(universal_player, UniversalPlayer):
581            universal_player.add_protocol_player(protocol_player.player_id)
582            for conn_type, value in protocol_player.device_info.identifiers.items():
583                universal_player.device_info.add_identifier(conn_type, value)
584            # Update model/manufacturer if universal player has generic values
585            self._update_universal_device_info(universal_player, protocol_player)
586
587            # Persist all player data (protocol IDs, identifiers, device info) to config
588            for provider in self.mass.get_providers(ProviderType.PLAYER):
589                if provider.domain == "universal_player":
590                    await cast("UniversalPlayerProvider", provider)._save_player_data(
591                        universal_player.player_id, universal_player
592                    )
593                    break
594
595            # Check if this universal player should now be merged with another
596            self._check_merge_universal_players(universal_player)
597
598        protocol_player.refresh_state()
599        universal_player.refresh_state()
600
601    def _update_universal_device_info(
602        self, universal_player: UniversalPlayer, protocol_player: Player
603    ) -> None:
604        """
605        Update universal player's device info from protocol player if needed.
606
607        A universal player carries generic placeholder device info
608        (model="Universal Player", manufacturer="Music Assistant") when no real
609        values are known for it (yet). This method updates those values from a
610        protocol player that has real device info.
611        """
612        # Check if universal player has generic placeholder device info
613        device_info = universal_player.device_info
614        protocol_info = protocol_player.device_info
615
616        # Update model if universal player has generic value
617        if device_info.model in (None, "Universal Player") and protocol_info.model:
618            device_info.model = protocol_info.model
619
620        # Update manufacturer if universal player has generic value
621        if device_info.manufacturer in (None, "Music Assistant") and protocol_info.manufacturer:
622            device_info.manufacturer = protocol_info.manufacturer
623
624    def _save_universal_player_data(self, universal_player: UniversalPlayer) -> None:
625        """
626        Save universal player data to config via background task.
627
628        This is a helper to persist player data from synchronous code.
629        """
630
631        async def _do_save() -> None:
632            for provider in self.mass.get_providers(ProviderType.PLAYER):
633                if provider.domain == "universal_player":
634                    await cast("UniversalPlayerProvider", provider)._save_player_data(
635                        universal_player.player_id, universal_player
636                    )
637                    break
638
639        self.mass.create_task(_do_save())
640
641    def _get_known_protocol_ids(self, parent: Player) -> list[str]:
642        """
643        Get all protocol IDs tracked for a parent player.
644
645        Includes both active links and cached/inactive protocol IDs so callers can
646        safely migrate or clean up the full parent/protocol relationship.
647        """
648        result: list[str] = []
649        seen: set[str] = set()
650
651        for linked in parent.linked_output_protocols:
652            if linked.output_protocol_id not in seen:
653                result.append(linked.output_protocol_id)
654                seen.add(linked.output_protocol_id)
655
656        if parent.provider.domain == "universal_player" and isinstance(parent, UniversalPlayer):
657            cached_ids = parent._protocol_player_ids
658        else:
659            cached_ids = self._get_cached_protocol_ids(parent.player_id)
660
661        for protocol_id in cached_ids:
662            if protocol_id not in seen:
663                result.append(protocol_id)
664                seen.add(protocol_id)
665
666        return result
667
668    def _migrate_protocol_ids_to_parent(self, parent: Player, protocol_ids: set[str]) -> None:
669        """
670        Persist protocol ownership on a new parent without requiring active links.
671
672        This is used when protocol ownership moves from one parent to another during
673        promotion/merge flows. Active protocols are already linked in memory, but
674        disabled or temporarily unavailable protocols still need their cached parent
675        relationship moved as well.
676        """
677        if not protocol_ids:
678            return
679
680        if parent.provider.domain == "universal_player" and isinstance(parent, UniversalPlayer):
681            for protocol_id in protocol_ids:
682                parent.add_protocol_player(protocol_id)
683            self._save_universal_player_data(parent)
684        else:
685            conf_key = f"{CONF_PLAYERS}/{parent.player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
686            cached_ids = self._get_cached_protocol_ids(parent.player_id)
687            changed = False
688            for protocol_id in protocol_ids:
689                if protocol_id not in cached_ids:
690                    cached_ids.append(protocol_id)
691                    changed = True
692            if changed:
693                self.mass.config.set(conf_key, cached_ids)
694
695        for protocol_id in protocol_ids:
696            if self.mass.config.get(f"{CONF_PLAYERS}/{protocol_id}"):
697                self._save_protocol_parent_id(protocol_id, parent.player_id)
698
699    def _remove_protocol_ids_from_parent(self, parent: Player, protocol_ids: set[str]) -> None:
700        """
701        Remove protocol ownership from a parent before it is permanently cleaned up.
702
703        This prevents `_cleanup_protocol_links` from treating already-migrated
704        protocols as orphaned when the obsolete parent is unregistered.
705        """
706        if not protocol_ids:
707            return
708
709        remaining_links = [
710            link
711            for link in parent.linked_output_protocols
712            if link.output_protocol_id not in protocol_ids
713        ]
714        if len(remaining_links) != len(parent.linked_output_protocols):
715            parent.set_linked_output_protocols(remaining_links)
716
717        if parent.provider.domain == "universal_player" and isinstance(parent, UniversalPlayer):
718            for protocol_id in protocol_ids:
719                parent.remove_protocol_player(protocol_id)
720            if self.mass.config.get(f"{CONF_PLAYERS}/{parent.player_id}"):
721                self.mass.config.set(
722                    f"{CONF_PLAYERS}/{parent.player_id}/values/{CONF_LINKED_PROTOCOL_IDS}",
723                    parent._protocol_player_ids,
724                )
725        else:
726            for protocol_id in protocol_ids:
727                self._remove_protocol_id_from_cache(parent.player_id, protocol_id)
728
729    def _check_merge_universal_players(self, universal_player: UniversalPlayer) -> None:
730        """
731        Check if another universal player should be merged into this one.
732
733        Called after identifiers are copied from a protocol player to a universal player.
734        When a protocol player brings new identifiers (e.g., MAC from ARP enrichment),
735        the universal player may now match another universal player that was created
736        from a different protocol (e.g., DLNA-based universal player now matches
737        AirPlay-based universal player because they share the same MAC address).
738
739        The oldest universal player absorbs the other one. Only one merge is performed
740        per call; re-evaluation will catch cascading merges.
741        """
742        if not (match := self._find_mergeable_universal_player(universal_player)):
743            return
744        keep, remove = self._select_merge_winner(universal_player, match)
745        self.logger.info(
746            "Merging universal player %s into %s (shared identifiers)",
747            remove.player_id,
748            keep.player_id,
749        )
750        self._merge_universal_players(keep, remove)
751
752    def _find_mergeable_universal_player(
753        self, universal_player: UniversalPlayer
754    ) -> UniversalPlayer | None:
755        """
756        Return the first other universal player that represents the same device, if any.
757
758        Players that share a protocol domain are not returned: they are separate devices
759        that merely share an identifier, so merging them would orphan a protocol.
760
761        :param universal_player: The universal player to find a merge candidate for.
762        """
763        for player in list(self._players.values()):
764            if player.provider.domain != "universal_player":
765                continue
766            if player.player_id == universal_player.player_id:
767                continue
768            if not isinstance(player, UniversalPlayer):
769                continue
770
771            if not self._identifiers_match(universal_player, player, ""):
772                continue
773
774            # Do not merge if both UPs have protocols from the same domain.
775            # Multiple instances of the same protocol on one host (e.g., several
776            # squeezelite players on the same VM) are separate devices that happen
777            # to share an IP. Merging them would orphan one instance's protocol.
778            domains_a = {
779                link.protocol_domain
780                for link in universal_player.linked_output_protocols
781                if link.protocol_domain
782            }
783            domains_b = {
784                link.protocol_domain
785                for link in player.linked_output_protocols
786                if link.protocol_domain
787            }
788            if domains_a & domains_b:
789                self.logger.debug(
790                    "Skipping merge of %s and %s: shared protocol domain(s) %s",
791                    universal_player.player_id,
792                    player.player_id,
793                    domains_a & domains_b,
794                )
795                continue
796
797            return player
798
799        return None
800
801    def _select_merge_winner(
802        self, universal_player: UniversalPlayer, other_player: UniversalPlayer
803    ) -> tuple[UniversalPlayer, UniversalPlayer]:
804        """
805        Return which of the two universal players absorbs the other, as (keeper, absorbed).
806
807        The oldest player wins, on a tie the one with the most protocol links.
808
809        :param universal_player: The universal player the merge was triggered for.
810        :param other_player: The universal player it matched with.
811        """
812        # The outcome must be stable across server restarts. Without that, which
813        # UniversalPlayer "wins" depends on iteration order of self._players.values(),
814        # which can shift between runs and causes downstream player_id reshuffling
815        # (and broken entity bindings in consumers like the Home Assistant MA integration).
816        if self._merge_rank(universal_player) <= self._merge_rank(other_player):
817            return universal_player, other_player
818        return other_player, universal_player
819
820    def _merge_rank(self, universal_player: Player) -> tuple[int, int, str]:
821        """
822        Return the sort key of a universal player in a merge, lowest wins.
823
824        Age comes first because the keeper's player id is the one that survives, and the
825        oldest player is the one API consumers have been bound to the longest. The links
826        of the absorbed player move over either way, so nothing is lost by keeping the
827        smaller one. A player from before player ids were minted has no stored moment and
828        counts as the oldest, which is exactly what it is.
829        """
830        created_at = self.mass.config.get(
831            f"{CONF_PLAYERS}/{universal_player.player_id}/values/{CONF_CREATED_AT}", 0
832        )
833        return (
834            created_at if isinstance(created_at, int) else 0,
835            -len(universal_player.linked_output_protocols),
836            universal_player.player_id,
837        )
838
839    def _merge_universal_players(self, keep: UniversalPlayer, remove: UniversalPlayer) -> None:
840        """
841        Absorb one universal player into another and schedule the absorbed one's removal.
842
843        :param keep: The universal player that stays.
844        :param remove: The universal player that is absorbed.
845        """
846        known_protocol_ids = set(self._get_known_protocol_ids(remove))
847        active_protocol_ids = {link.output_protocol_id for link in remove.linked_output_protocols}
848        moved_protocol_ids: set[str] = set()
849
850        # Transfer protocol links from the removed player to the keeper
851        for linked in list(remove.linked_output_protocols):
852            if protocol_player := self.get_player(linked.output_protocol_id):
853                protocol_player.set_protocol_parent_id(None)
854                domain = linked.protocol_domain or protocol_player.provider.domain
855
856                # Check if keeper already has an active link from this domain
857                if self._parent_has_active_protocol_from_domain(keep, domain):
858                    self.logger.debug(
859                        "Skipping duplicate %s link during merge: %s",
860                        domain,
861                        linked.output_protocol_id,
862                    )
863                    continue
864
865                self._add_protocol_link(keep, protocol_player, domain)
866                if protocol_player.protocol_parent_id == keep.player_id:
867                    moved_protocol_ids.add(protocol_player.player_id)
868                    protocol_player.refresh_state()
869
870        # Move cached-only protocol ownership as well so old-parent cleanup
871        # does not wipe protocols that were intentionally preserved.
872        cached_only_ids = known_protocol_ids - active_protocol_ids
873        preserved_protocol_ids = moved_protocol_ids | cached_only_ids
874        self._migrate_protocol_ids_to_parent(keep, preserved_protocol_ids)
875        self._remove_protocol_ids_from_parent(remove, preserved_protocol_ids)
876
877        # Merge identifiers
878        for conn_type, value in remove.device_info.identifiers.items():
879            keep.device_info.add_identifier(conn_type, value)
880        keep.refresh_state()
881
882        # Persist updated data before the obsolete player is removed
883        self._save_universal_player_data(keep)
884
885        # Carry over the user's configuration and re-point group memberships
886        # before the permanent removal below deletes the losing wrapper's config
887        self._migrate_universal_player_config(remove.player_id, keep.player_id)
888        self._update_group_memberships(remove.player_id, keep.player_id)
889
890        # Stop playback and remove the obsolete player
891        self.mass.create_task(self._stop_and_unregister(remove, keep.player_id))
892
893    def _link_protocols_to_universal(
894        self, universal_player: Player, protocol_players: list[Player]
895    ) -> None:
896        """Link protocol players to a universal player, cleaning up existing links."""
897        for player in protocol_players:
898            # Clean up if linked to another player
899            if player.protocol_parent_id:
900                if parent := self.get_player(player.protocol_parent_id):
901                    self._remove_protocol_link(parent, player.player_id)
902                player.set_protocol_parent_id(None)
903            # Link to universal player
904            self._add_protocol_link(universal_player, player, player.provider.domain)
905            player.refresh_state()
906
907        # Update availability from protocol players
908        universal_player.refresh_state()
909
910    async def _create_or_update_universal_player(self, protocol_players: list[Player]) -> None:
911        """
912        Create or update a UniversalPlayer for a set of protocol players.
913
914        Delegates to the universal player provider which handles orchestration,
915        locking, and player creation. The controller then links the protocols
916        to the universal player.
917        """
918        # Filter out players that got linked during the async delay
919        protocol_players = [p for p in protocol_players if not p.protocol_parent_id]
920        if not protocol_players:
921            return
922
923        # Get the universal_player provider
924        universal_provider: UniversalPlayerProvider | None = None
925        for provider in self.mass.get_providers(ProviderType.PLAYER):
926            if provider.domain == "universal_player":
927                universal_provider = cast("UniversalPlayerProvider", provider)
928                break
929
930        if not universal_provider:
931            return
932
933        # Delegate to provider - it handles locking, create/update decision, etc.
934        # It reports which universal player each protocol player belongs to, as a
935        # device with several instances of one protocol domain gets more than one.
936        assignments = await universal_provider.ensure_universal_players_for_protocols(
937            protocol_players
938        )
939
940        # Link the protocols to their universal player (the controller manages
941        # cross-provider state), skipping players that were linked in the meantime.
942        by_universal_player: dict[str, list[Player]] = {}
943        for player in protocol_players:
944            if player.protocol_parent_id:
945                continue
946            if universal_player := assignments.get(player.player_id):
947                by_universal_player.setdefault(universal_player.player_id, []).append(player)
948
949        for universal_player_id, players in by_universal_player.items():
950            if universal_player := self.get_player(universal_player_id):
951                self._link_protocols_to_universal(universal_player, players)
952
953    def _try_link_protocols_to_native(self, native_player: Player) -> None:
954        """Try to link protocol players to a native player."""
955        # First, check if there's a universal player for this device that should be replaced
956        self._check_replace_universal_player(native_player)
957
958        # Look for protocol players that should be linked
959        for protocol_player in self.all_players(return_protocol_players=True):
960            if protocol_player.state.type != PlayerType.PROTOCOL:
961                continue
962            if protocol_player.protocol_parent_id:
963                # Already linked to a parent (could be this native player after replacement)
964                continue
965            if protocol_player.underlying_player_id:
966                # Derived protocol players link via their underlying player instead
967                continue
968
969            protocol_domain = protocol_player.provider.domain
970
971            # Skip if this native player already has an active link from this domain
972            # (prevents a second instance of the same protocol from trying to link)
973            if self._parent_has_active_protocol_from_domain(native_player, protocol_domain):
974                continue
975
976            if self._identifiers_match(native_player, protocol_player, protocol_domain):
977                self._add_protocol_link(native_player, protocol_player, protocol_domain)
978                # Check if linking succeeded (may be refused for duplicate domain)
979                if protocol_player.protocol_parent_id is not None:
980                    protocol_player.refresh_state()
981                    native_player.refresh_state()
982
983        # Proactively recover disabled/missing protocols from config
984        # This ensures disabled protocols show up in the UI so they can be re-enabled
985        self._recover_cached_protocol_links(native_player)
986
987        # Second pass: match remaining unlinked protocol players via sibling identifiers.
988        # After cache recovery, the native player has linked protocols (e.g., AirPlay)
989        # whose identifiers can be used to match new protocol players (e.g., Sendspin bridge)
990        # that share the same device identifiers but couldn't match the native player directly.
991        for protocol_player in self.all_players(return_protocol_players=True):
992            if protocol_player.state.type != PlayerType.PROTOCOL:
993                continue
994            if protocol_player.protocol_parent_id:
995                continue
996            if protocol_player.underlying_player_id:
997                continue
998            protocol_domain = protocol_player.provider.domain
999            if self._parent_has_active_protocol_from_domain(native_player, protocol_domain):
1000                continue
1001            if self._match_via_linked_protocols(native_player, protocol_player, protocol_domain):
1002                self.logger.debug(
1003                    "Linked %s to %s via sibling protocol identifiers",
1004                    protocol_player.player_id,
1005                    native_player.player_id,
1006                )
1007
1008        # Finally, link derived protocol players that ride directly on this
1009        # native player (derived players riding on the protocol players linked
1010        # above are handled by _add_protocol_link itself).
1011        self._link_derived_protocols_of(native_player)
1012
1013    def _check_replace_universal_player(self, native_player: Player) -> None:
1014        """Check if a universal player should be replaced by this native player."""
1015        # Skip if native_player is itself a universal player (prevent self-replacement)
1016        if native_player.provider.domain == "universal_player":
1017            return
1018
1019        # Look for universal players that match this native player
1020        for player in list(self._players.values()):
1021            if player.provider.domain != "universal_player":
1022                continue
1023
1024            # Check by identifiers first
1025            identifiers_match = self._identifiers_match(native_player, player, "")
1026
1027            # Also check if native player's ID is in the universal player's stored protocol list
1028            # This handles players that changed type (e.g., sendspin web players changed from
1029            # PROTOCOL to PLAYER type) and have no identifiers to match against
1030            player_id_in_protocols = (
1031                isinstance(player, UniversalPlayer)
1032                and native_player.player_id in player._protocol_player_ids
1033            )
1034
1035            if not identifiers_match and not player_id_in_protocols:
1036                continue
1037
1038            known_protocol_ids = set(self._get_known_protocol_ids(player))
1039            refused_protocol_ids: set[str] = set()
1040            moved_protocol_ids: set[str] = set()
1041
1042            # Transfer the protocol links from the universal player to the native player.
1043            # A derived protocol rides on another output, so a base and everything riding
1044            # on it can only move together: refusing one of them holds back the group.
1045            for group in self._group_protocol_links(player):
1046                domains = {
1047                    protocol_player.player_id: linked.protocol_domain
1048                    or protocol_player.provider.domain
1049                    for linked, protocol_player in group
1050                }
1051                if any(
1052                    self._parent_has_active_protocol_from_domain(
1053                        native_player, domain, exclude_player_id=protocol_id
1054                    )
1055                    for protocol_id, domain in domains.items()
1056                ):
1057                    refused_protocol_ids.update(domains.keys())
1058                    continue
1059                for _, protocol_player in group:
1060                    protocol_player.set_protocol_parent_id(None)
1061                    self._add_protocol_link(
1062                        native_player, protocol_player, domains[protocol_player.player_id]
1063                    )
1064                    if protocol_player.protocol_parent_id != native_player.player_id:
1065                        # Link refused, keep the protocol owned by the universal player.
1066                        protocol_player.set_protocol_parent_id(player.player_id)
1067                        refused_protocol_ids.add(protocol_player.player_id)
1068                        continue
1069                    protocol_player.refresh_state()
1070                    moved_protocol_ids.add(protocol_player.player_id)
1071
1072            # A refused link leaves the universal player in charge, so only hand over what
1073            # actually moved: ownership that exists in config alone stays with it, which
1074            # keeps a protocol derived from a refused one with the parent it will link to.
1075            migrated_protocol_ids = (
1076                moved_protocol_ids if refused_protocol_ids else known_protocol_ids
1077            )
1078            # A device that kept its id across a type change lists itself here.
1079            # It must never become its own protocol, and it must also be dropped
1080            # from the obsolete universal player so the permanent cleanup below
1081            # doesn't treat it as an orphaned protocol (which would re-wrap the
1082            # native player in a fresh universal player).
1083            migrated_protocol_ids.discard(native_player.player_id)
1084            self._migrate_protocol_ids_to_parent(native_player, migrated_protocol_ids)
1085            self._remove_protocol_ids_from_parent(
1086                player, migrated_protocol_ids | {native_player.player_id}
1087            )
1088            native_player.refresh_state()
1089
1090            if refused_protocol_ids:
1091                # Registered protocols that the native player refused remain on the wrapper.
1092                continue
1093
1094            # Carry over the user's configuration and re-point group memberships
1095            # before the permanent removal below deletes the universal player's config
1096            self._migrate_universal_player_config(player.player_id, native_player.player_id)
1097            self._update_group_memberships(player.player_id, native_player.player_id)
1098
1099            # Stop playback and remove the now-obsolete universal player
1100            self.mass.create_task(self._stop_and_unregister(player, native_player.player_id))
1101
1102    def _group_protocol_links(
1103        self, parent: Player
1104    ) -> list[list[tuple[LinkedOutputProtocol, Player]]]:
1105        """
1106        Group a parent's registered protocol links with the protocols riding on them.
1107
1108        Each group holds one base protocol followed by the derived protocols that ride
1109        on it. A protocol whose underlying player is not one of the parent's own links
1110        forms a group of its own.
1111
1112        :param parent: The parent player whose protocol links should be grouped.
1113        """
1114        registered = [
1115            (linked, protocol_player)
1116            for linked in parent.linked_output_protocols
1117            if (protocol_player := self.get_player(linked.output_protocol_id))
1118        ]
1119        link_ids = {protocol_player.player_id for _, protocol_player in registered}
1120        riders: dict[str, list[tuple[LinkedOutputProtocol, Player]]] = {}
1121        bases: list[tuple[LinkedOutputProtocol, Player]] = []
1122        for linked, protocol_player in registered:
1123            underlying_id = protocol_player.underlying_player_id
1124            if underlying_id and underlying_id in link_ids:
1125                riders.setdefault(underlying_id, []).append((linked, protocol_player))
1126            else:
1127                bases.append((linked, protocol_player))
1128
1129        groups = [
1130            [(linked, protocol_player), *riders.get(protocol_player.player_id, [])]
1131            for linked, protocol_player in bases
1132        ]
1133        # A derived protocol riding on another derived protocol has no base group here,
1134        # so it moves on its own rather than being dropped from the transfer.
1135        grouped_ids = {
1136            protocol_player.player_id for group in groups for _, protocol_player in group
1137        }
1138        groups.extend([entry] for entry in registered if entry[1].player_id not in grouped_ids)
1139        return groups
1140
1141    def _migrate_universal_player_config(self, universal_id: str, native_id: str) -> None:
1142        """
1143        Carry over user-set configuration from a replaced universal player.
1144
1145        Copies the custom display name, player config values, DSP settings and
1146        per-queue settings of the (obsolete) universal player onto the native
1147        player that replaces it, without overwriting values explicitly set on
1148        the native player itself. Must be called while the universal player's
1149        config still exists, as the permanent removal deletes it.
1150
1151        :param universal_id: Player id of the obsolete universal player being replaced.
1152        :param native_id: Player id of the native player that replaces it.
1153        """
1154        source_raw = self.mass.config.get(f"{CONF_PLAYERS}/{universal_id}")
1155        source_raw = source_raw if isinstance(source_raw, dict) else {}
1156        target_key = f"{CONF_PLAYERS}/{native_id}"
1157        target_raw = self.mass.config.get(target_key)
1158        target_raw = target_raw if isinstance(target_raw, dict) else {}
1159        player_config_changed = False
1160
1161        # only carry an actual user rename, not the auto-generated default name;
1162        # likewise a name on the native player only counts as a user override when
1163        # it differs from the default name
1164        custom_name = source_raw.get("name")
1165        target_name = target_raw.get("name")
1166        target_has_custom_name = bool(target_name) and target_name != target_raw.get("default_name")
1167        if (
1168            custom_name
1169            and custom_name != source_raw.get("default_name")
1170            and not target_has_custom_name
1171        ):
1172            self.mass.config.set(f"{target_key}/name", custom_name)
1173            player_config_changed = True
1174
1175        source_values = source_raw.get("values")
1176        source_values = source_values if isinstance(source_values, dict) else {}
1177        target_values = target_raw.get("values")
1178        target_values = target_values if isinstance(target_values, dict) else {}
1179        for key, value in source_values.items():
1180            if key in UNIVERSAL_PLAYER_INTERNAL_CONF_KEYS:
1181                continue
1182            if CONF_PROTOCOL_KEY_SPLITTER in key:
1183                # stale virtual mirror of a protocol player's own config
1184                continue
1185            if key in target_values:
1186                continue
1187            self.mass.config.set(f"{target_key}/values/{key}", deepcopy(value))
1188            player_config_changed = True
1189
1190        # DSP settings follow wholesale, unless the native player has its own
1191        dsp_changed = False
1192        source_dsp = self.mass.config.get(f"{CONF_PLAYER_DSP}/{universal_id}")
1193        if source_dsp and not self.mass.config.get(f"{CONF_PLAYER_DSP}/{native_id}"):
1194            self.mass.config.set(f"{CONF_PLAYER_DSP}/{native_id}", deepcopy(source_dsp))
1195            dsp_changed = True
1196
1197        queue_changed = self._migrate_universal_queue_config(universal_id, native_id)
1198
1199        if not (player_config_changed or dsp_changed or queue_changed):
1200            return
1201        self.logger.info(
1202            "Carried over configuration of universal player %s to %s", universal_id, native_id
1203        )
1204        if player_config_changed:
1205            # the native player's in-place config was loaded before the carry-over,
1206            # so reload it to make the migrated values (e.g. custom name) effective
1207            self.mass.create_task(self._reapply_player_config(native_id))
1208
1209    def _migrate_universal_queue_config(self, universal_id: str, native_id: str) -> bool:
1210        """
1211        Move the per-queue settings of a replaced universal player to its replacement.
1212
1213        Queue ids equal player ids, so the source entry is removed once it is carried over.
1214
1215        :param universal_id: Player id of the obsolete universal player.
1216        :param native_id: Player id of the native player that replaces it.
1217        :return: True if any queue setting was carried over.
1218        """
1219        queue_changed = False
1220        source_queue_raw = self.mass.config.get(f"{CONF_PLAYER_QUEUES}/{universal_id}")
1221        source_queue_raw = source_queue_raw if isinstance(source_queue_raw, dict) else None
1222        if source_queue_values := (source_queue_raw or {}).get("values"):
1223            target_queue_key = f"{CONF_PLAYER_QUEUES}/{native_id}"
1224            target_queue_raw = self.mass.config.get(target_queue_key)
1225            target_queue_raw = (
1226                deepcopy(target_queue_raw) if isinstance(target_queue_raw, dict) else {}
1227            )
1228            target_queue_values = target_queue_raw.setdefault("values", {})
1229            for key, value in source_queue_values.items():
1230                if key in target_queue_values:
1231                    continue
1232                target_queue_values[key] = deepcopy(value)
1233                queue_changed = True
1234            if queue_changed:
1235                target_queue_raw["queue_id"] = native_id
1236                self.mass.config.set(target_queue_key, target_queue_raw)
1237        if source_queue_raw is not None:
1238            self.mass.config.remove(f"{CONF_PLAYER_QUEUES}/{universal_id}")
1239        return queue_changed
1240
1241    async def _reapply_player_config(self, player_id: str) -> None:
1242        """Reload the stored config onto a registered player and refresh its state."""
1243        if not (player := self.get_player(player_id)):
1244            return
1245        config = await self.mass.config.get_player_config(player_id)
1246        player.set_config(config)
1247        player.update_state()
1248        self.mass.signal_event(EventType.PLAYER_CONFIG_UPDATED, object_id=player_id, data=config)
1249
1250    def _update_group_memberships(self, old_player_id: str, new_player_id: str | None) -> None:
1251        """
1252        Hand a removed player's group memberships over to its successor, or drop them.
1253
1254        Other players that list the removed player as a group member (or allowed
1255        member) must follow its successor so those memberships are not silently
1256        lost. Without a successor the player is gone for good and its id is dropped
1257        from the group members instead, so it can not linger in a group and pull a
1258        device that returns under the same id back in. Its allow-list entry is left
1259        alone there, since an allow-list that runs empty stops restricting at all.
1260        Updates the persisted config and keeps any registered player whose
1261        membership changed in sync.
1262
1263        :param old_player_id: Player id that is being removed.
1264        :param new_player_id: Player id that replaces it, or None if there is none.
1265        """
1266        all_player_configs = self.mass.config.get(CONF_PLAYERS, {})
1267        if not isinstance(all_player_configs, dict):
1268            return
1269        for other_id, other_cfg in all_player_configs.items():
1270            if not isinstance(other_cfg, dict):
1271                continue
1272            other_values = other_cfg.get("values")
1273            if not isinstance(other_values, dict):
1274                continue
1275            other_player = self.get_player(other_id)
1276            changed = False
1277            for key in (CONF_GROUP_MEMBERS, CONF_ALLOWED_MEMBERS):
1278                members = other_values.get(key)
1279                if not isinstance(members, list) or old_player_id not in members:
1280                    continue
1281                if new_player_id is None and key == CONF_ALLOWED_MEMBERS:
1282                    # an allow-list that runs empty reads as "everyone may join", so the
1283                    # entry of a removed player stays: it can never join again anyway
1284                    continue
1285                new_members: list[str] = []
1286                for member_id in members:
1287                    resolved = new_player_id if member_id == old_player_id else member_id
1288                    if resolved is not None and resolved not in new_members:
1289                        new_members.append(resolved)
1290                self.mass.config.set(f"{CONF_PLAYERS}/{other_id}/values/{key}", new_members)
1291                changed = True
1292                # keep a registered player's in-place config copy in sync
1293                if other_player and (entry := other_player.config.values.get(key)):
1294                    entry.value = new_members
1295            if changed and other_player:
1296                self.mass.create_task(self._reload_group_members(other_player))
1297
1298    async def _reload_group_members(self, player: Player) -> None:
1299        """
1300        Let a group re-read its member config so its live member list follows along.
1301
1302        :param player: The group player whose stored member list changed.
1303        """
1304        await player.on_config_updated()
1305        player.refresh_state()
1306
1307    async def _stop_and_unregister(self, player: Player, replacement_player_id: str) -> None:
1308        """
1309        Stop active playback on a player and then permanently unregister it.
1310
1311        Used when an obsolete universal player is replaced or merged away: while
1312        it is not idle its protocol child keeps playing the dead queue's stream
1313        until the buffer drains, so playback is stopped first. Queue ownership is
1314        intentionally not transferred.
1315
1316        :param player: The obsolete player to stop and permanently remove.
1317        :param replacement_player_id: Player ID that takes the obsolete player's place.
1318        """
1319        if player.playback_state != PlaybackState.IDLE:
1320            with suppress(PlayerCommandFailed, PlayerUnavailableError):
1321                await self.mass.player_queues.stop(player.player_id)
1322        await self.unregister(
1323            player.player_id, permanent=True, replacement_player_id=replacement_player_id
1324        )
1325
1326    def _parent_has_active_protocol_from_domain(
1327        self, parent: Player, domain: str, exclude_player_id: str | None = None
1328    ) -> bool:
1329        """
1330        Check if a parent already has an active (registered) protocol player from a given domain.
1331
1332        This prevents a second protocol player of the same domain (e.g., a second AirPlay
1333        instance on the same host) from replacing the first one's link on the same parent.
1334
1335        :param parent: The parent player to check.
1336        :param domain: The protocol domain to check for (e.g., "airplay", "dlna").
1337        :param exclude_player_id: Optional player ID to exclude from the check
1338            (used when checking if a player's own domain is already linked).
1339        """
1340        for link in parent.linked_output_protocols:
1341            if link.protocol_domain != domain:
1342                continue
1343            if exclude_player_id and link.output_protocol_id == exclude_player_id:
1344                continue
1345            # A registered player from this domain blocks the link, even if unavailable.
1346            # Being offline doesn't make it a different device — it's still occupying
1347            # this domain slot. The provider should remove stale players explicitly.
1348            if self.get_player(link.output_protocol_id):
1349                return True
1350        return False
1351
1352    def _add_protocol_link(
1353        self, native_player: Player, protocol_player: Player, protocol_domain: str
1354    ) -> None:
1355        """Add a protocol link from native player to protocol player."""
1356        # Never link a player to itself (hides it as its own protocol child).
1357        if native_player.player_id == protocol_player.player_id:
1358            return
1359        # Guard: refuse to replace an existing active link from the same domain.
1360        # This prevents a second instance of the same protocol (e.g., two AirPlay
1361        # instances on the same host) from silently replacing the first one.
1362        if self._parent_has_active_protocol_from_domain(
1363            native_player, protocol_domain, exclude_player_id=protocol_player.player_id
1364        ):
1365            self.logger.debug(
1366                "Refusing to link %s to %s: parent already has an active %s link",
1367                protocol_player.player_id,
1368                native_player.player_id,
1369                protocol_domain,
1370            )
1371            return
1372
1373        # Remove any existing link for the same protocol domain
1374        updated_protocols = [
1375            link
1376            for link in native_player.linked_output_protocols
1377            if link.protocol_domain != protocol_domain
1378        ]
1379
1380        # Get priority for this protocol
1381        priority = PROTOCOL_PRIORITY.get(protocol_domain, 100)
1382
1383        # Derived transports (e.g. a Sendspin bridge riding on an AirPlay player)
1384        # reference the base output they run on top of; "native" when they ride
1385        # on the parent player itself
1386        derived_from = protocol_player.underlying_player_id
1387        if derived_from == native_player.player_id:
1388            derived_from = "native"
1389
1390        # Add the new link
1391        updated_protocols.append(
1392            LinkedOutputProtocol(
1393                output_protocol_id=protocol_player.player_id,
1394                protocol_domain=protocol_domain,
1395                priority=priority,
1396                derived_from=derived_from,
1397            )
1398        )
1399        native_player.set_linked_output_protocols(updated_protocols)
1400
1401        # Set protocol player's parent
1402        protocol_player.set_protocol_parent_id(native_player.player_id)
1403
1404        # Persist linked protocol IDs to config for fast restart
1405        # (only for non-universal players, as universal players handle this themselves)
1406        if native_player.provider.domain != "universal_player":
1407            self._save_linked_protocol_ids(native_player)
1408        # Always save the parent ID on the protocol player for reverse lookup on restart
1409        # (needed for both native and universal parents to enable fast restore)
1410        self._save_protocol_parent_id(protocol_player.player_id, native_player.player_id)
1411
1412        # The freshly linked player may have derived protocol players (e.g. a
1413        # Sendspin bridge riding on it) waiting to join the same parent.
1414        self._link_derived_protocols_of(protocol_player)
1415
1416    def _remove_protocol_link(
1417        self, native_player: Player, protocol_player_id: str, permanent: bool = False
1418    ) -> None:
1419        """
1420        Remove a protocol link.
1421
1422        :param native_player: The parent player to remove the link from.
1423        :param protocol_player_id: The protocol player ID to unlink.
1424        :param permanent: If True, also removes the protocol ID from the cached list.
1425            Use this when the protocol player config is being deleted. If False,
1426            the protocol ID remains in the cache so it can be shown as disabled
1427            and re-enabled later.
1428        """
1429        updated_protocols = [
1430            link
1431            for link in native_player.linked_output_protocols
1432            if link.output_protocol_id != protocol_player_id
1433        ]
1434        native_player.set_linked_output_protocols(updated_protocols)
1435
1436        # Clear parent reference on protocol player if it still exists
1437        if protocol_player := self.get_player(protocol_player_id):
1438            if protocol_player.protocol_parent_id == native_player.player_id:
1439                protocol_player.set_protocol_parent_id(None)
1440
1441        # Update persisted linked protocol IDs
1442        if native_player.provider.domain != "universal_player":
1443            if permanent:
1444                # Permanently remove from cache (player config is being deleted)
1445                self._remove_protocol_id_from_cache(native_player.player_id, protocol_player_id)
1446            # Note: we don't call _save_linked_protocol_ids here anymore for non-permanent
1447            # removals because the merge approach will preserve the ID in the cache
1448        # Always clear the cached parent ID (for both native and universal parents)
1449        self._clear_protocol_parent_id(protocol_player_id)
1450
1451    def _save_linked_protocol_ids(self, native_player: Player) -> None:
1452        """
1453        Save linked protocol IDs to config for persistence across restarts.
1454
1455        This method merges active protocol IDs with existing cached IDs to preserve
1456        disabled protocol players in the cache. This allows disabled protocols to be
1457        shown in the UI so they can be re-enabled.
1458        """
1459        conf_key = f"{CONF_PLAYERS}/{native_player.player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1460        # Get existing cached IDs to preserve disabled protocols
1461        existing_ids: list[str] = self.mass.config.get(conf_key, [])
1462        # Get currently active protocol IDs
1463        active_ids = {link.output_protocol_id for link in native_player.linked_output_protocols}
1464        # Merge: keep existing IDs and add any new active ones
1465        merged_ids = list(existing_ids)
1466        for protocol_id in active_ids:
1467            if protocol_id not in merged_ids:
1468                merged_ids.append(protocol_id)
1469        self.mass.config.set(conf_key, merged_ids)
1470
1471    def _get_cached_protocol_ids(self, player_id: str) -> list[str]:
1472        """Get cached linked protocol IDs from config."""
1473        conf_key = f"{CONF_PLAYERS}/{player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1474        result = self.mass.config.get(conf_key, [])
1475        return list(result) if result else []
1476
1477    def _remove_protocol_id_from_cache(
1478        self, parent_player_id: str, protocol_player_id: str
1479    ) -> None:
1480        """
1481        Permanently remove a protocol player ID from the cached linked protocol IDs.
1482
1483        Use this when a protocol player config is being deleted, not just disabled.
1484        """
1485        conf_key = f"{CONF_PLAYERS}/{parent_player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1486        cached_ids: list[str] = self.mass.config.get(conf_key, [])
1487        if protocol_player_id in cached_ids:
1488            cached_ids.remove(protocol_player_id)
1489            self.mass.config.set(conf_key, cached_ids)
1490
1491    def _save_protocol_parent_id(self, protocol_player_id: str, parent_id: str) -> None:
1492        """Save the parent ID for a protocol player for persistence across restarts."""
1493        # Only save if the player config still exists to avoid creating partial entries
1494        if not self.mass.config.get(f"{CONF_PLAYERS}/{protocol_player_id}"):
1495            return
1496        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1497        self.mass.config.set(conf_key, parent_id)
1498
1499    def _save_underlying_player_id(self, player: Player) -> None:
1500        """
1501        Persist the derived-transport edge of a player to config.
1502
1503        Allows the edge to be resolved (e.g. by the config UI) even while the
1504        player is not registered. Clears a previously persisted edge when the
1505        player is no longer derived (e.g. a bridge client turned web player).
1506        """
1507        # Only save if the player config still exists to avoid creating partial entries
1508        if not self.mass.config.get(f"{CONF_PLAYERS}/{player.player_id}"):
1509            return
1510        conf_key = f"{CONF_PLAYERS}/{player.player_id}/values/{CONF_UNDERLYING_PLAYER_ID}"
1511        if player.underlying_player_id:
1512            self.mass.config.set(conf_key, player.underlying_player_id)
1513        elif self.mass.config.get(conf_key) is not None:
1514            self.mass.config.set(conf_key, None)
1515
1516    def _get_cached_protocol_parent_id(self, protocol_player_id: str) -> str | None:
1517        """Get cached parent ID for a protocol player from config."""
1518        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1519        result = self.mass.config.get(conf_key, None)
1520        return str(result) if result else None
1521
1522    def _clear_protocol_parent_id(self, protocol_player_id: str) -> None:
1523        """Clear the cached parent ID for a protocol player."""
1524        # Only clear if the player config still exists to avoid creating partial entries
1525        if not self.mass.config.get(f"{CONF_PLAYERS}/{protocol_player_id}"):
1526            return
1527        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1528        self.mass.config.set(conf_key, None)
1529
1530    def _recover_cached_protocol_links(self, native_player: Player) -> None:
1531        """
1532        Recover protocol links from config for disabled/missing protocols.
1533
1534        This ensures that disabled protocols show up in the output_protocols list
1535        so they can be re-enabled by the user. It also handles the case where
1536        protocol players haven't registered yet during startup.
1537        """
1538        # Get currently linked protocol IDs
1539        linked_protocol_ids = {
1540            link.output_protocol_id for link in native_player.linked_output_protocols
1541        }
1542
1543        # Get cached protocol IDs from config (includes protocols that were explicitly linked)
1544        cached_protocol_ids = self._get_cached_protocol_ids(native_player.player_id)
1545
1546        # Also check all protocol players that have protocol_parent_id pointing to this player
1547        # (this handles disabled protocols that may not be in linked_protocol_ids)
1548        all_player_configs = self.mass.config.get(CONF_PLAYERS, {})
1549        for protocol_id, protocol_config in all_player_configs.items():
1550            # Skip if not a protocol player
1551            if protocol_config.get("player_type") != "protocol":
1552                continue
1553            # Check if this protocol has a parent_id pointing to this native player
1554            protocol_values = protocol_config.get("values", {})
1555            protocol_parent_id = protocol_values.get(CONF_PROTOCOL_PARENT_ID)
1556            if protocol_parent_id == native_player.player_id:
1557                if protocol_id not in cached_protocol_ids:
1558                    cached_protocol_ids.append(protocol_id)
1559
1560        if not cached_protocol_ids:
1561            return
1562
1563        # Add link entries for any cached protocols that aren't currently linked
1564        updated_protocols = list(native_player.linked_output_protocols)
1565        for protocol_id in cached_protocol_ids:
1566            if protocol_id in linked_protocol_ids:
1567                continue  # Already linked
1568
1569            # Get protocol player config to determine the protocol domain
1570            protocol_config = self.mass.config.get(f"{CONF_PLAYERS}/{protocol_id}")
1571            if not protocol_config:
1572                continue
1573
1574            # Determine protocol domain from provider
1575            protocol_provider: str = protocol_config.get("provider")
1576            if not protocol_provider:
1577                continue
1578
1579            # Extract domain from provider instance_id (e.g., "airplay--uuid" -> "airplay")
1580            protocol_domain = protocol_provider.split("--", maxsplit=1)[0]
1581
1582            # Skip if parent already has a link from this domain
1583            existing_domains = {link.protocol_domain for link in updated_protocols}
1584            if protocol_domain in existing_domains:
1585                continue
1586
1587            # Get priority for this protocol
1588            priority = PROTOCOL_PRIORITY.get(protocol_domain, 100)
1589
1590            # Resolve the derived-transport edge from the live player when
1591            # registered, else from the persisted edge in config
1592            protocol_player = self.get_player(protocol_id)
1593            derived_from = (
1594                protocol_player.underlying_player_id
1595                if protocol_player
1596                else protocol_config.get("values", {}).get(CONF_UNDERLYING_PLAYER_ID)
1597            )
1598            if derived_from == native_player.player_id:
1599                derived_from = "native"
1600
1601            updated_protocols.append(
1602                LinkedOutputProtocol(
1603                    output_protocol_id=protocol_id,
1604                    protocol_domain=protocol_domain,
1605                    priority=priority,
1606                    derived_from=derived_from,
1607                )
1608            )
1609            self.logger.debug(
1610                "Recovered cached protocol link %s -> %s",
1611                native_player.player_id,
1612                protocol_id,
1613            )
1614
1615        if len(updated_protocols) != len(native_player.linked_output_protocols):
1616            native_player.set_linked_output_protocols(updated_protocols)
1617
1618    def _cleanup_protocol_links(self, player: Player) -> None:
1619        """Clean up protocol links when a player is permanently removed."""
1620        if player.state.type == PlayerType.PROTOCOL:
1621            self._unlink_from_protocol_parent(player)
1622            return
1623        self._detach_owned_protocols(player)
1624
1625    def _unlink_from_protocol_parent(self, player: Player) -> None:
1626        """Release a protocol player from the parent it is attached to."""
1627        if parent_id := player.protocol_parent_id:
1628            if parent_player := self.get_player(parent_id):
1629                # Use permanent=True to also remove from cached protocol IDs
1630                self._remove_protocol_link(parent_player, player.player_id, permanent=True)
1631                if (
1632                    parent_player.provider.domain == "universal_player"
1633                    and len(parent_player.linked_output_protocols) == 0
1634                ):
1635                    # No protocols left - the universal player has nothing to play
1636                    # on. Its config is deliberately kept: the player id is opaque
1637                    # and cannot be recreated, so deleting it here would orphan the
1638                    # entities API consumers bound to it. Only an explicit removal
1639                    # by the user deletes a universal player for good.
1640                    self.logger.info(
1641                        "Universal player %s has no protocols left",
1642                        parent_id,
1643                    )
1644                    self.mass.create_task(self.mass.players.unregister(parent_id, permanent=False))
1645                else:
1646                    parent_player.refresh_state()
1647            else:
1648                # Parent not registered yet — still purge the cached id
1649                self._remove_protocol_id_from_cache(parent_id, player.player_id)
1650
1651    def _detach_owned_protocols(self, player: Player) -> None:
1652        """Detach the protocol players a parent owns so they can find a new parent."""
1653        # collect the ids from both the active links and the cached state, since
1654        # disabled/inactive protocols may only exist in the cached parent data
1655        all_protocol_ids = set(self._get_known_protocol_ids(player))
1656        for protocol_id in all_protocol_ids:
1657            if protocol_player := self.get_player(protocol_id):
1658                # Protocol player is available: clear parent and schedule re-evaluation
1659                # so it can be matched to a new parent or a new universal player
1660                self.logger.debug(
1661                    "Player %s no longer owns protocol %s - scheduling evaluation",
1662                    player.player_id,
1663                    protocol_id,
1664                )
1665                self._detach_protocol_child(protocol_player)
1666            else:
1667                # Clear cached parent ID in config so protocol won't try to
1668                # restore a link to its former parent on next restart
1669                self._clear_protocol_parent_id(protocol_id)
1670                # Protocol player is not registered yet — it may still be
1671                # mid-discovery (e.g., DLNA connecting via SSDP). Don't delete
1672                # its config as that would cause a KeyError when it finishes
1673                # registering. Stale configs are harmless and get cleaned up
1674                # naturally on subsequent restarts.
1675                self.logger.debug(
1676                    "Player %s no longer owns protocol %s - not registered, skipping cleanup",
1677                    player.player_id,
1678                    protocol_id,
1679                )
1680
1681    def _cleanup_player_type_transition(self, existing: Player, *, becomes_protocol: bool) -> None:
1682        """
1683        Release the protocol topology a player owned before its type changed.
1684
1685        :param existing: The registered player instance for the changed player.
1686        :param becomes_protocol: True if the player moves into the protocol role,
1687            False if it leaves it.
1688        """
1689        if not becomes_protocol:
1690            # a provider may announce the new type with the live parent link already
1691            # dropped, so fall back to the persisted one to still reach the parent
1692            parent_id = existing.protocol_parent_id or self._get_cached_protocol_parent_id(
1693                existing.player_id
1694            )
1695            if not parent_id:
1696                return
1697            parent = self.get_player(parent_id)
1698            if parent is not None and parent.provider.domain == "universal_player":
1699                # drop only the active edge and leave the rest to the link evaluation,
1700                # which replaces the wrapper with this player: a leftover edge makes it
1701                # hand the player over to itself, which it refuses, abandoning the swap
1702                self._remove_protocol_link(parent, existing.player_id)
1703                return
1704            existing.set_protocol_parent_id(parent_id)
1705            # unlink at the parent and drop the persisted parent id, which would
1706            # otherwise heal the player's type back to protocol
1707            self._unlink_from_protocol_parent(existing)
1708            # a player leaving the protocol role has no parent, also when that parent
1709            # is not registered (anymore) and only the cached link could be cleaned up
1710            existing.set_protocol_parent_id(None)
1711            return
1712        # the player becomes a child itself: detach the protocol players it owned so they
1713        # can find a new parent, then give up their ownership in its (kept) config - the
1714        # reverse of the removal path, which drops the ownership before the detach
1715        protocol_ids = set(self._get_known_protocol_ids(existing))
1716        self._detach_owned_protocols(existing)
1717        self._remove_protocol_ids_from_parent(existing, protocol_ids)
1718
1719    def _detach_protocol_children(self, parent_id: str) -> None:
1720        """
1721        Detach the registered protocol players of a parent player that is going away.
1722
1723        Covers the removal paths that don't unregister the parent first (e.g. its
1724        provider is unloaded), where the parent is not around anymore to enumerate
1725        its protocol players.
1726
1727        :param parent_id: Player id of the parent that is being removed.
1728        """
1729        for protocol_player in list(self._players.values()):
1730            if protocol_player.state.type != PlayerType.PROTOCOL:
1731                continue
1732            # a protocol player waiting for a parent that never registered only has
1733            # the link in its config, so fall back to the cached parent
1734            linked_parent_id = protocol_player.protocol_parent_id or (
1735                self._get_cached_protocol_parent_id(protocol_player.player_id)
1736            )
1737            if linked_parent_id != parent_id:
1738                continue
1739            self.logger.debug(
1740                "Player %s removed - scheduling evaluation for protocol %s",
1741                parent_id,
1742                protocol_player.player_id,
1743            )
1744            self._detach_protocol_child(protocol_player)
1745
1746    def _detach_protocol_child(self, protocol_player: Player) -> None:
1747        """Clear a protocol player's parent link and schedule a fresh evaluation."""
1748        self._clear_protocol_parent_id(protocol_player.player_id)
1749        protocol_player.set_protocol_parent_id(None)
1750        protocol_player.refresh_state()
1751        self._schedule_protocol_evaluation(protocol_player)
1752
1753    def _identifiers_match(
1754        self, player_a: Player, player_b: Player, protocol_domain: str = ""
1755    ) -> bool:
1756        """
1757        Check if identifiers match between two players.
1758
1759        Matching is done by comparing connection identifiers (MAC, serial, UUID).
1760        As a last resort, IP address is used when at least one player has a
1761        locally-administered MAC, indicating the device uses MAC randomization
1762        and ARP could not resolve the real hardware address.
1763
1764        Invalid identifiers (e.g., 00:00:00:00:00:00 MAC addresses) are filtered out
1765        to prevent false matches between unrelated devices.
1766        """
1767        identifiers_a = player_a.device_info.identifiers
1768        identifiers_b = player_b.device_info.identifiers
1769
1770        # Check identifiers in order of reliability
1771        # MAC_ADDRESS > SERIAL_NUMBER > UUID > CAST_UUID > AIRPLAY_ID
1772        for conn_type in (
1773            IdentifierType.MAC_ADDRESS,
1774            IdentifierType.SERIAL_NUMBER,
1775            IdentifierType.UUID,
1776            IdentifierType.CAST_UUID,
1777            IdentifierType.AIRPLAY_ID,
1778        ):
1779            val_a = identifiers_a.get(conn_type)
1780            val_b = identifiers_b.get(conn_type)
1781
1782            if not val_a or not val_b:
1783                continue
1784
1785            # Filter out invalid MAC addresses (00:00:00:00:00:00, ff:ff:ff:ff:ff:ff)
1786            if conn_type == IdentifierType.MAC_ADDRESS:
1787                if not is_valid_mac_address(val_a) or not is_valid_mac_address(val_b):
1788                    self.logger.log(
1789                        VERBOSE_LOG_LEVEL,
1790                        "Skipping invalid MAC address for matching: %s=%s, %s=%s",
1791                        player_a.display_name,
1792                        val_a,
1793                        player_b.display_name,
1794                        val_b,
1795                    )
1796                    continue
1797
1798            # Normalize values for comparison
1799            if conn_type == IdentifierType.MAC_ADDRESS:
1800                # Use MAC normalization that handles locally-administered bit differences
1801                # Some protocols (like AirPlay) report a locally-administered MAC variant
1802                # where bit 1 of the first octet is set (e.g., 54:78:... vs 56:78:...)
1803                val_a_norm = normalize_mac_for_matching(val_a)
1804                val_b_norm = normalize_mac_for_matching(val_b)
1805
1806                # Direct match on current MAC
1807                if val_a_norm == val_b_norm:
1808                    return True
1809
1810                # Multi-MAC matching: also check original reported MACs.
1811                # Devices with multiple interfaces (WiFi + Ethernet) may have ARP
1812                # resolve one MAC while the protocol reports a different one.
1813                macs_a = {val_a_norm}
1814                macs_b = {val_b_norm}
1815                reported_a = player_a.extra_data.get("reported_mac")
1816                reported_b = player_b.extra_data.get("reported_mac")
1817                if reported_a and is_valid_mac_address(reported_a):
1818                    macs_a.add(normalize_mac_for_matching(reported_a))
1819                if reported_b and is_valid_mac_address(reported_b):
1820                    macs_b.add(normalize_mac_for_matching(reported_b))
1821                if macs_a & macs_b:
1822                    return True
1823
1824                # No MAC match - continue to next identifier type
1825                continue
1826
1827            val_a_norm = val_a.lower().replace(":", "").replace("-", "")
1828            val_b_norm = val_b.lower().replace(":", "").replace("-", "")
1829
1830            # Direct match
1831            if val_a_norm == val_b_norm:
1832                return True
1833
1834            # Special case: Sonos UUID matching with DLNA _MR suffix
1835            # Sonos uses RINCON_xxx, DLNA uses RINCON_xxx_MR for Media Renderer
1836            if conn_type == IdentifierType.UUID:
1837                if val_b_norm.endswith("_mr") and val_b_norm[:-3] == val_a_norm:
1838                    return True
1839                if val_a_norm.endswith("_mr") and val_a_norm[:-3] == val_b_norm:
1840                    return True
1841
1842        # Last resort: IP-based matching.
1843        # Two players on the same IP are very likely the same physical device.
1844        # This handles two cases:
1845        # 1. MAC randomization: at least one player has no real MAC (LA or missing),
1846        #    so ARP couldn't resolve a usable address.
1847        # 2. Different MACs per protocol: some devices (e.g., Yamaha MusicCast) report
1848        #    different valid globally-unique MACs per protocol (DLNA vs AirPlay differ
1849        #    by 1 in the last octet). IP matching is safe here because two different
1850        #    devices on a LAN cannot share the same IP simultaneously.
1851        #    To avoid false positives between unrelated native players, this path
1852        #    requires at least one player to be a protocol or universal player.
1853        ip_a = identifiers_a.get(IdentifierType.IP_ADDRESS)
1854        ip_b = identifiers_b.get(IdentifierType.IP_ADDRESS)
1855        if ip_a and ip_b and ip_a == ip_b:
1856            mac_a = identifiers_a.get(IdentifierType.MAC_ADDRESS)
1857            mac_b = identifiers_b.get(IdentifierType.MAC_ADDRESS)
1858            a_is_real = (
1859                mac_a is not None
1860                and is_valid_mac_address(mac_a)
1861                and not is_locally_administered_mac(mac_a)
1862            )
1863            b_is_real = (
1864                mac_b is not None
1865                and is_valid_mac_address(mac_b)
1866                and not is_locally_administered_mac(mac_b)
1867            )
1868            # Case 1: at least one player has no real hardware MAC
1869            if not (a_is_real and b_is_real):
1870                return True
1871            # Case 2: both have real MACs but at least one is a protocol/universal player
1872            a_is_protocol = (
1873                player_a.type == PlayerType.PROTOCOL
1874                or player_a.provider.domain == "universal_player"
1875            )
1876            b_is_protocol = (
1877                player_b.type == PlayerType.PROTOCOL
1878                or player_b.provider.domain == "universal_player"
1879            )
1880            if a_is_protocol or b_is_protocol:
1881                return True
1882
1883        return False
1884
1885    def _select_best_output_protocol(self, player: Player) -> tuple[Player, OutputProtocol | None]:
1886        """
1887        Select the best available output protocol for a player.
1888
1889        Selection priority:
1890        1. Output protocol that is currently grouped/synced with other players.
1891        2. User's preferred output protocol (from player settings).
1892        3. Native playback (if player supports PLAY_MEDIA).
1893        4. The player's declared default output protocol domain, if available.
1894        5. Best available protocol by priority.
1895
1896        Returns tuple of (target_player, output_protocol).
1897        output_protocol is None when using native playback.
1898        """
1899        self.logger.log(
1900            VERBOSE_LOG_LEVEL,
1901            "Selecting output protocol for %s",
1902            player.state.name,
1903        )
1904
1905        # 1. Check if any output protocol is currently grouped
1906        for linked in player.linked_output_protocols:
1907            if protocol_player := self.get_player(linked.output_protocol_id):
1908                if protocol_player.available_for_playback and self._is_protocol_grouped(
1909                    protocol_player
1910                ):
1911                    self.logger.log(
1912                        VERBOSE_LOG_LEVEL,
1913                        "Selected protocol for %s: %s (grouped)",
1914                        player.state.name,
1915                        protocol_player.state.name,
1916                    )
1917                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1918
1919        # 2. Check for user's preferred output protocol.
1920        # The value is only stored while it differs from the entry's default: "native" when a
1921        # native output is available, otherwise "auto". A player without a native output (e.g. a
1922        # LinkPlay shell) therefore has no stored preference by default and gets its default
1923        # output domain applied in step 4.
1924        preferred = self.mass.config.get_raw_player_config_value(
1925            player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
1926        )
1927        if preferred and preferred != "auto":
1928            if preferred == "native":
1929                if PlayerFeature.PLAY_MEDIA in player.supported_features:
1930                    self.logger.log(
1931                        VERBOSE_LOG_LEVEL,
1932                        "Selected protocol for %s: native (user preference)",
1933                        player.state.name,
1934                    )
1935                    return player, None
1936            else:
1937                for linked in player.linked_output_protocols:
1938                    if linked.output_protocol_id == preferred:
1939                        if protocol_player := self.get_player(linked.output_protocol_id):
1940                            if protocol_player.available_for_playback:
1941                                self.logger.log(
1942                                    VERBOSE_LOG_LEVEL,
1943                                    "Selected protocol for %s: %s (user preference)",
1944                                    player.state.name,
1945                                    protocol_player.state.name,
1946                                )
1947                                return protocol_player, player.get_linked_protocol(
1948                                    linked.output_protocol_id
1949                                )
1950                        break
1951
1952        # 3. Use native playback if available
1953        if PlayerFeature.PLAY_MEDIA in player.supported_features:
1954            self.logger.log(
1955                VERBOSE_LOG_LEVEL, "Selected protocol for %s: native", player.state.name
1956            )
1957            return player, None
1958
1959        # 4. Use the player's preferred default protocol domain, if it declares one and a
1960        # matching linked protocol is available (e.g. a LinkPlay shell prefers DLNA). This
1961        # never influences grouping; it only steers the default output for playback. "Auto"
1962        # is the entry default here, so it consistently resolves to this domain default.
1963        if default_domain := player.default_output_protocol_domain:
1964            for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
1965                if linked.protocol_domain != default_domain:
1966                    continue
1967                if (protocol_player := self.get_player(linked.output_protocol_id)) and (
1968                    protocol_player.available_for_playback
1969                ):
1970                    self.logger.log(
1971                        VERBOSE_LOG_LEVEL,
1972                        "Selected protocol for %s: %s (default domain %s)",
1973                        player.state.name,
1974                        protocol_player.state.name,
1975                        default_domain,
1976                    )
1977                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1978
1979        # 5. Fall back to best protocol by priority
1980        for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
1981            if protocol_player := self.get_player(linked.output_protocol_id):
1982                if protocol_player.available_for_playback:
1983                    self.logger.log(
1984                        VERBOSE_LOG_LEVEL,
1985                        "Selected protocol for %s: %s (priority-based)",
1986                        player.state.name,
1987                        protocol_player.state.name,
1988                    )
1989                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1990
1991        raise PlayerCommandFailed(f"Player {player.state.name} has no available output protocols")
1992
1993    def _get_control_target(
1994        self,
1995        player: Player,
1996        required_feature: PlayerFeature,
1997        require_active: bool = False,
1998    ) -> Player | None:
1999        """
2000        Get the best player(protocol) to send audio-path commands to.
2001
2002        Resolves commands that travel with the audio (enqueue, pause, announcements),
2003        so the output that renders the audio outranks the native player. Volume and
2004        mute are control-plane instead and resolve through
2005        :meth:`Player._get_protocol_player_for_feature`, which orders differently.
2006
2007        :param player: The player the command was issued on.
2008        :param required_feature: The feature the resolved target has to support.
2009        :param require_active: Only accept the output that is already rendering,
2010            instead of falling back to an idle one.
2011        """
2012        # If we have an active protocol, use that
2013        if (
2014            player.active_output_protocol
2015            and player.active_output_protocol != "native"
2016            and (protocol_player := self.mass.players.get_player(player.active_output_protocol))
2017            and required_feature in protocol_player.supported_features
2018        ):
2019            return protocol_player
2020
2021        # if the player natively supports the required feature, use that
2022        if (
2023            player.active_output_protocol == "native"
2024            and required_feature in player.supported_features
2025        ):
2026            return player
2027
2028        # If require_active is set, and no active protocol found, return None
2029        if require_active:
2030            return None
2031
2032        # if the player natively supports the required feature, use that
2033        if required_feature in player.supported_features:
2034            return player
2035
2036        # An output the user explicitly picked owns the audio, so a command that has to
2037        # start playback on an idle player follows it rather than the priority below.
2038        # The stored value survives a relink, so it only counts while it still names one
2039        # of this player's own outputs.
2040        preferred = self.mass.config.get_raw_player_config_value(
2041            player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
2042        )
2043        if preferred and preferred not in ("auto", "native"):
2044            for linked in player.linked_output_protocols:
2045                if linked.output_protocol_id != preferred:
2046                    continue
2047                if (
2048                    (preferred_player := self.mass.players.get_player(str(preferred)))
2049                    and preferred_player.available_for_playback
2050                    and required_feature in preferred_player.supported_features
2051                ):
2052                    return preferred_player
2053                break
2054
2055        # Otherwise, use the best available linked protocol, ordered by the same
2056        # priority that regular playback selection applies.
2057        for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
2058            if (
2059                (protocol_player := self.mass.players.get_player(linked.output_protocol_id))
2060                and protocol_player.available_for_playback
2061                and required_feature in protocol_player.supported_features
2062            ):
2063                return protocol_player
2064
2065        return None
2066
2067    def _is_protocol_grouped(self, protocol_player: Player) -> bool:
2068        """
2069        Check if a protocol player is currently grouped/synced with other players.
2070
2071        Used to prefer protocols that are actively participating in a group,
2072        ensuring consistent playback across grouped players.
2073        """
2074        is_grouped = bool(
2075            protocol_player.state.synced_to
2076            or (
2077                protocol_player.state.group_members and len(protocol_player.state.group_members) > 1
2078            )
2079            or protocol_player.state.active_group
2080        )
2081        if is_grouped:
2082            self.logger.log(
2083                VERBOSE_LOG_LEVEL,
2084                "Protocol player %s is grouped",
2085                protocol_player.state.name,
2086            )
2087        return is_grouped
2088
2089    def _translate_members_to_remove_for_protocols(
2090        self,
2091        parent_player: Player,
2092        player_ids: list[str],
2093        parent_protocol_player: Player | None,
2094        parent_protocol_domain: str | None,
2095    ) -> tuple[list[str], list[str]]:
2096        """
2097        Translate member IDs to remove into protocol and native lists.
2098
2099        :param parent_player: The parent player to remove members from.
2100        :param player_ids: List of visible player IDs to remove.
2101        :param parent_protocol_player: The parent's protocol player if available.
2102        :param parent_protocol_domain: The parent's protocol domain if available.
2103        """
2104        self.logger.debug(
2105            "Translating members to remove for %s: player_ids=%s, parent_protocol_domain=%s",
2106            parent_player.state.name,
2107            player_ids,
2108            parent_protocol_domain,
2109        )
2110        protocol_members: list[str] = []
2111        native_members: list[str] = []
2112
2113        for child_player_id in player_ids:
2114            child_player = self.get_player(child_player_id)
2115            if not child_player:
2116                continue
2117
2118            # Check if this member is in the parent's group via protocol
2119            if parent_protocol_domain and parent_protocol_player:
2120                child_protocol = child_player.get_output_protocol_by_domain(parent_protocol_domain)
2121                if child_protocol and child_protocol.available:
2122                    # For native protocol players, use the child's player_id directly
2123                    child_protocol_id = (
2124                        child_player.player_id
2125                        if child_protocol.is_native
2126                        else child_protocol.output_protocol_id
2127                    )
2128                    if child_protocol_id in parent_protocol_player.group_members:
2129                        self.logger.debug(
2130                            "Translating removal: %s -> protocol %s",
2131                            child_player_id,
2132                            child_protocol_id,
2133                        )
2134                        protocol_members.append(child_protocol_id)
2135                        continue
2136
2137            # Check if child's protocol player is in parent's native group_members
2138            # This handles native protocol players (e.g., native AirPlay player like Apple TV)
2139            # where the parent itself contains protocol player IDs in its group_members
2140            translated = False
2141            for linked in child_player.linked_output_protocols:
2142                if linked.output_protocol_id in parent_player.group_members:
2143                    self.logger.debug(
2144                        "Translating removal (native parent): %s -> protocol %s",
2145                        child_player_id,
2146                        linked.output_protocol_id,
2147                    )
2148                    native_members.append(linked.output_protocol_id)
2149                    translated = True
2150                    break
2151
2152            if not translated:
2153                native_members.append(child_player_id)
2154
2155        return protocol_members, native_members
2156
2157    def _filter_protocol_members(self, member_ids: list[str], protocol_player: Player) -> list[str]:
2158        """Filter member IDs to only include players from the same protocol domain."""
2159        return [
2160            pid
2161            for pid in member_ids
2162            if (p := self.get_player(pid)) and p.provider.domain == protocol_player.provider.domain
2163        ]
2164
2165    def _filter_native_members(self, member_ids: list[str], parent_player: Player) -> list[str]:
2166        """Filter member IDs to only include players compatible with the parent."""
2167        return [
2168            pid
2169            for pid in member_ids
2170            if (p := self.get_player(pid))
2171            and (
2172                p.provider.instance_id == parent_player.provider.instance_id
2173                or pid in parent_player._attr_can_group_with
2174                or p.provider.instance_id in parent_player._attr_can_group_with
2175            )
2176        ]
2177
2178    def _try_child_preferred_protocol(
2179        self,
2180        child_player: Player,
2181        parent_player: Player,
2182    ) -> tuple[str | None, str | None]:
2183        """
2184        Try to use child's preferred output protocol for grouping.
2185
2186        Returns tuple of (child_protocol_id, protocol_domain) or (None, None).
2187        """
2188        child_preferred = self.mass.config.get_raw_player_config_value(
2189            child_player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
2190        )
2191        if not child_preferred or child_preferred in {"auto", "native"}:
2192            return None, None
2193
2194        # Find child's preferred protocol, with its current availability
2195        child_protocol = None
2196        for output_protocol in child_player.output_protocols:
2197            if output_protocol.output_protocol_id == child_preferred:
2198                child_protocol = output_protocol
2199                break
2200
2201        if not child_protocol or not child_protocol.available:
2202            return None, None
2203
2204        # Check if parent supports this protocol (including native protocol)
2205        parent_protocol = parent_player.get_output_protocol_by_domain(
2206            child_protocol.protocol_domain
2207        )
2208        if not parent_protocol or not parent_protocol.available:
2209            return None, None
2210
2211        # Check if this protocol supports set_members
2212        protocol_player = parent_player.get_protocol_player(parent_protocol.output_protocol_id)
2213        if (
2214            not protocol_player
2215            or PlayerFeature.SET_MEMBERS not in protocol_player.state.supported_features
2216        ):
2217            return None, None
2218
2219        return child_protocol.output_protocol_id, child_protocol.protocol_domain
2220
2221    def _can_use_native_grouping(
2222        self,
2223        child_player: Player,
2224        parent_player: Player,
2225        parent_supports_native: bool,
2226    ) -> bool:
2227        """Check if child can be grouped with parent using native grouping."""
2228        if not parent_supports_native:
2229            return False
2230        return (
2231            parent_player.is_native_group_compatible(child_player)
2232            or child_player.player_id in parent_player._attr_can_group_with
2233            or child_player.provider.instance_id in parent_player._attr_can_group_with
2234        )
2235
2236    def _try_find_common_protocol(
2237        self, child_player: Player, parent_player: Player
2238    ) -> tuple[OutputProtocol | None, OutputProtocol | None]:
2239        """
2240        Find common protocol that supports set_members.
2241
2242        Returns tuple of (parent_protocol, child_protocol) or (None, None).
2243        """
2244        for parent_output_protocol in parent_player.output_protocols:
2245            if not parent_output_protocol.available:
2246                continue
2247            child_protocol = child_player.get_output_protocol_by_domain(
2248                parent_output_protocol.protocol_domain
2249            )
2250            if not child_protocol or not child_protocol.available:
2251                continue
2252            protocol_player = parent_player.get_protocol_player(
2253                parent_output_protocol.output_protocol_id
2254            )
2255            if protocol_player and PlayerFeature.SET_MEMBERS in protocol_player.supported_features:
2256                return parent_output_protocol, child_protocol
2257        return None, None
2258
2259    def _parent_has_live_native_session(self, parent_player: Player) -> bool:
2260        """
2261        Return True when the parent currently holds a live native playback session.
2262
2263        The active output protocol lingers for a few seconds after stop, so a non-idle
2264        playback state is required to distinguish a real session from a just-stopped one.
2265        """
2266        return parent_player.active_output_protocol == "native" and (
2267            parent_player.state.playback_state in (PlaybackState.PLAYING, PlaybackState.PAUSED)
2268        )
2269
2270    def _order_members_for_native_join(
2271        self,
2272        player_ids: list[str],
2273        parent_player: Player,
2274        parent_supports_native_grouping: bool,
2275    ) -> list[str]:
2276        """
2277        Order members so a live native session can be joined without splitting the group.
2278
2279        When the parent already holds a live native session, children that cannot group
2280        natively are evaluated first: they may force a shared protocol for the whole group,
2281        and processing them before the native-capable children lets those join that same
2282        protocol instead of being stranded in a separate native sub-group. The order is left
2283        untouched when the parent is not playing natively, so fresh-group selection is unchanged.
2284
2285        :param player_ids: The member IDs to be added, in their original order.
2286        :param parent_player: The parent player being joined.
2287        :param parent_supports_native_grouping: Whether the parent can group natively.
2288        """
2289        if not self._parent_has_live_native_session(parent_player):
2290            return player_ids
2291        return sorted(
2292            player_ids,
2293            key=lambda pid: bool(
2294                (child := self.get_player(pid))
2295                and self._can_use_native_grouping(
2296                    child, parent_player, parent_supports_native_grouping
2297                )
2298            ),
2299        )
2300
2301    def _try_join_active_native_session(
2302        self,
2303        child_player: Player,
2304        parent_player: Player,
2305        parent_protocol_domain: str | None,
2306        parent_supports_native_grouping: bool,
2307        native_members: list[str],
2308    ) -> bool:
2309        """
2310        Add the child to native_members if it can join the parent's active native session.
2311
2312        A child's preferred output protocol must only steer protocol selection when the child
2313        initiates its own playback; when it joins a parent that is already playing natively it
2314        should adopt native grouping if compatible, rather than forcing the whole group onto
2315        the child's preferred protocol. Skipped once a protocol has been selected for the group,
2316        so mixed batches stay cohesive on a single protocol.
2317
2318        :param child_player: The player being added to the group.
2319        :param parent_player: The parent player being joined.
2320        :param parent_protocol_domain: The protocol domain already selected for the group, if any.
2321        :param parent_supports_native_grouping: Whether the parent can group natively.
2322        :param native_members: The native members list to append to when the child joins.
2323        """
2324        if not (
2325            self._parent_has_live_native_session(parent_player)
2326            and not parent_protocol_domain
2327            and self._can_use_native_grouping(
2328                child_player, parent_player, parent_supports_native_grouping
2329            )
2330        ):
2331            return False
2332        native_members.append(child_player.player_id)
2333        self.logger.log(
2334            VERBOSE_LOG_LEVEL,
2335            "Joining parent's active native session for %s",
2336            child_player.state.name,
2337        )
2338        return True
2339
2340    def _translate_native_members_to_protocol(
2341        self, parent_player: Player, protocol_domain: str, member_ids: list[str]
2342    ) -> list[str]:
2343        """
2344        Translate natively grouped members onto the protocol domain the parent plays through.
2345
2346        Members that do not have that protocol cannot follow the parent at all and are
2347        dropped with a warning instead.
2348
2349        :param parent_player: The parent player the members are grouped with.
2350        :param protocol_domain: The protocol domain selected for the group.
2351        :param member_ids: The member IDs that were selected for native grouping.
2352        """
2353        translated: list[str] = []
2354        for member_id in member_ids:
2355            member_player = self.get_player(member_id)
2356            if not member_player:
2357                continue
2358            # a native group's members may be listed by their protocol player id
2359            if member_player.protocol_parent_id:
2360                member_player = self.get_player(member_player.protocol_parent_id) or member_player
2361            member_protocol = member_player.get_output_protocol_by_domain(protocol_domain)
2362            if not member_protocol or not member_protocol.available:
2363                self.logger.warning(
2364                    "Cannot group %s with %s: the group plays through the %s protocol, "
2365                    "which %s does not support",
2366                    member_player.state.name,
2367                    parent_player.state.name,
2368                    protocol_domain,
2369                    member_player.state.name,
2370                )
2371                continue
2372            # For native protocol players, use the member's player_id directly
2373            translated.append(
2374                member_player.player_id
2375                if member_protocol.is_native
2376                else member_protocol.output_protocol_id
2377            )
2378            self.logger.log(
2379                VERBOSE_LOG_LEVEL,
2380                "Moving %s from native grouping to the %s protocol",
2381                member_player.state.name,
2382                protocol_domain,
2383            )
2384        return translated
2385
2386    def _move_native_members_to_group_protocol(
2387        self,
2388        parent_player: Player,
2389        parent_protocol_player: Player | None,
2390        parent_protocol_domain: str | None,
2391        protocol_members: list[str],
2392        native_members: list[str],
2393    ) -> None:
2394        """
2395        Move the members selected for native grouping onto the protocol the group ended up on.
2396
2397        Does nothing unless the group ends up on one of the parent's protocols while the
2398        parent's native grouping needs the parent's own stream: only then do those members
2399        have no session left to attach to.
2400
2401        :param parent_player: The parent player being joined.
2402        :param parent_protocol_player: The protocol player selected for the group, if any.
2403        :param parent_protocol_domain: The protocol domain selected for the group, if any.
2404        :param protocol_members: The protocol member list the translated IDs are added to.
2405        :param native_members: The native member IDs, emptied when they are moved over.
2406        """
2407        if not (
2408            native_members
2409            and parent_protocol_domain
2410            and parent_protocol_player
2411            and parent_protocol_player.player_id != parent_player.player_id
2412            and parent_player.native_grouping_requires_own_stream
2413        ):
2414            return
2415        protocol_members.extend(
2416            self._translate_native_members_to_protocol(
2417                parent_player, parent_protocol_domain, native_members
2418            )
2419        )
2420        native_members.clear()
2421
2422    def _migrate_stranded_native_members(
2423        self,
2424        parent_player: Player,
2425        parent_protocol_player: Player,
2426        protocol_members: list[str],
2427    ) -> list[str]:
2428        """
2429        Move the native members that a switch to the given protocol strands onto that protocol.
2430
2431        Returns the member IDs that are still attached to the parent's own stream, so the
2432        caller can release them from it. Empty unless the parent renders that stream itself
2433        while its native grouping attaches the members to exactly that stream: only then are
2434        they left without anything to play.
2435
2436        :param parent_player: The parent player that is about to switch protocol.
2437        :param parent_protocol_player: The protocol player the parent will render through.
2438        :param protocol_members: The protocol member list the translated IDs are added to.
2439        """
2440        if parent_protocol_player.player_id == parent_player.player_id:
2441            return []
2442        if not parent_player.native_grouping_requires_own_stream:
2443            return []
2444        if parent_player.active_output_protocol not in (None, "native"):
2445            return []
2446        if parent_player.state.playback_state not in (PlaybackState.PLAYING, PlaybackState.PAUSED):
2447            return []
2448        stranded = [
2449            member_id
2450            for member_id in parent_player.group_members
2451            if member_id != parent_player.player_id
2452        ]
2453        for protocol_id in self._translate_native_members_to_protocol(
2454            parent_player, parent_protocol_player.provider.domain, stranded
2455        ):
2456            if protocol_id not in protocol_members:
2457                protocol_members.append(protocol_id)
2458        return stranded
2459
2460    async def _stop_native_session(
2461        self,
2462        parent_player: Player,
2463        parent_protocol_player: Player,
2464        stranded_native_members: list[str],
2465    ) -> None:
2466        """
2467        Release the given members from the parent's own stream and stop it.
2468
2469        :param parent_player: The parent player whose native session is handed over.
2470        :param parent_protocol_player: The protocol player taking the output over.
2471        :param stranded_native_members: The members to release, already migrated.
2472        """
2473        self.logger.debug(
2474            "Stopping the native session of %s before switching to %s, migrated members: %s",
2475            parent_player.state.name,
2476            parent_protocol_player.state.name,
2477            stranded_native_members,
2478        )
2479        # The members already joined the protocol group, so the native session only has to
2480        # release them and stop. Releasing them first also clears the native group, which
2481        # keeps a later native playback command from resurrecting it. Both calls take the
2482        # provider's own lock, so they must run one after the other.
2483        await parent_player.set_members(player_ids_to_remove=stranded_native_members)
2484        await parent_player.stop()
2485
2486    def _translate_members_for_protocols(
2487        self,
2488        parent_player: Player,
2489        player_ids: list[str],
2490        parent_protocol_player: Player | None,
2491        parent_protocol_domain: str | None,
2492    ) -> tuple[list[str], list[str], Player | None, str | None]:
2493        """
2494        Translate member IDs to protocol or native IDs.
2495
2496        The grouping method is picked per member, see _select_grouping_for_member.
2497
2498        Returns tuple of (protocol_members, native_members, protocol_player, protocol_domain).
2499        """
2500        protocol_members: list[str] = []
2501        native_members: list[str] = []
2502        parent_supports_native_grouping = (
2503            PlayerFeature.SET_MEMBERS in parent_player.supported_features
2504        )
2505        player_ids = self._order_members_for_native_join(
2506            player_ids, parent_player, parent_supports_native_grouping
2507        )
2508
2509        self.logger.log(
2510            VERBOSE_LOG_LEVEL,
2511            "Translating members for %s: parent_supports_native=%s, parent_protocol=%s (%s)",
2512            parent_player.state.name,
2513            parent_supports_native_grouping,
2514            parent_protocol_player.state.name if parent_protocol_player else "none",
2515            parent_protocol_domain or "none",
2516        )
2517
2518        for child_player_id in player_ids:
2519            child_player = self.get_player(child_player_id)
2520            if not child_player:
2521                continue
2522
2523            self.logger.log(
2524                VERBOSE_LOG_LEVEL,
2525                "Processing child %s (type=%s, protocols=%s)",
2526                child_player.state.name,
2527                child_player.state.type,
2528                [p.protocol_domain for p in child_player.output_protocols],
2529            )
2530
2531            parent_protocol_player, parent_protocol_domain = self._select_grouping_for_member(
2532                child_player,
2533                parent_player,
2534                parent_protocol_player,
2535                parent_protocol_domain,
2536                parent_supports_native_grouping,
2537                protocol_members,
2538                native_members,
2539            )
2540
2541        # Post-pass: the protocol selected for the group is only known once every child has
2542        # been processed, so the members picked for native grouping are corrected here.
2543        self._move_native_members_to_group_protocol(
2544            parent_player,
2545            parent_protocol_player,
2546            parent_protocol_domain,
2547            protocol_members,
2548            native_members,
2549        )
2550
2551        return protocol_members, native_members, parent_protocol_player, parent_protocol_domain
2552
2553    def _select_grouping_for_member(
2554        self,
2555        child_player: Player,
2556        parent_player: Player,
2557        parent_protocol_player: Player | None,
2558        parent_protocol_domain: str | None,
2559        parent_supports_native_grouping: bool,
2560        protocol_members: list[str],
2561        native_members: list[str],
2562    ) -> tuple[Player | None, str | None]:
2563        """
2564        Pick the grouping method for a single member and add it to the matching member list.
2565
2566        Selection priority when grouping:
2567        0. If the parent is already playing natively and the child can be grouped
2568           natively, join that native session (a child joining an existing group must
2569           not force the whole group onto its own preferred output protocol)
2570        1. Try child's preferred output protocol (from player settings)
2571        2. Try parent's active output protocol (if any and child supports it)
2572        3. Try native grouping (if parent and child are compatible)
2573        4. Search for common protocol that supports set_members
2574        5. Log warning if no option works
2575
2576        Returns the protocol player/domain the group is on, which the picked method may have
2577        changed.
2578
2579        :param child_player: The player being added to the group.
2580        :param parent_player: The parent player being joined.
2581        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2582        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2583        :param parent_supports_native_grouping: Whether the parent can group natively.
2584        :param protocol_members: The protocol member list to append to.
2585        :param native_members: The native member list to append to.
2586        """
2587        # Priority 0: The parent is already playing natively and the child can join
2588        # that native session directly - adopt it before considering the child's own
2589        # preferred output protocol.
2590        if self._try_join_active_native_session(
2591            child_player,
2592            parent_player,
2593            parent_protocol_domain,
2594            parent_supports_native_grouping,
2595            native_members,
2596        ):
2597            return parent_protocol_player, parent_protocol_domain
2598
2599        # Priority 0.5: a player that runs its own multiroom (e.g. a LinkPlay control shell)
2600        # keeps grouping on its native path rather than routing it through a linked protocol
2601        # that is merely its preferred playback output. Native compatibility still decides
2602        # whether this is possible, so an incompatible/cross-backend pair falls through.
2603        if child_player.prefer_native_grouping and self._can_use_native_grouping(
2604            child_player, parent_player, parent_supports_native_grouping
2605        ):
2606            native_members.append(child_player.player_id)
2607            self.logger.log(
2608                VERBOSE_LOG_LEVEL,
2609                "Using native grouping (preferred) for %s",
2610                child_player.state.name,
2611            )
2612            return parent_protocol_player, parent_protocol_domain
2613
2614        # Priority 1: the child's preferred output protocol
2615        grouped, parent_protocol_player, parent_protocol_domain = (
2616            self._try_group_via_preferred_protocol(
2617                child_player,
2618                parent_player,
2619                parent_protocol_player,
2620                parent_protocol_domain,
2621                protocol_members,
2622            )
2623        )
2624        if grouped:
2625            return parent_protocol_player, parent_protocol_domain
2626
2627        # Priority 2: the protocol the group is already on
2628        grouped, parent_protocol_player, parent_protocol_domain = (
2629            self._try_group_via_active_protocol(
2630                child_player,
2631                parent_protocol_player,
2632                parent_protocol_domain,
2633                protocol_members,
2634            )
2635        )
2636        if grouped:
2637            return parent_protocol_player, parent_protocol_domain
2638
2639        # Priority 3: native grouping
2640        if self._can_use_native_grouping(
2641            child_player, parent_player, parent_supports_native_grouping
2642        ):
2643            native_members.append(child_player.player_id)
2644            self.logger.log(
2645                VERBOSE_LOG_LEVEL,
2646                "Using native grouping for %s",
2647                child_player.state.name,
2648            )
2649            return parent_protocol_player, parent_protocol_domain
2650
2651        # Priority 4: a protocol both players share that supports set_members
2652        grouped, parent_protocol_player, parent_protocol_domain = (
2653            self._try_group_via_common_protocol(
2654                child_player,
2655                parent_player,
2656                parent_protocol_player,
2657                parent_protocol_domain,
2658                protocol_members,
2659            )
2660        )
2661        if grouped:
2662            return parent_protocol_player, parent_protocol_domain
2663
2664        # Priority 5: no option worked
2665        self.logger.warning(
2666            "Cannot group %s with %s: no compatible grouping method found "
2667            "(tried: child preferred protocol, parent active protocol, "
2668            "native grouping, common protocols)",
2669            child_player.state.name,
2670            parent_player.state.name,
2671        )
2672        return parent_protocol_player, parent_protocol_domain
2673
2674    def _try_group_via_preferred_protocol(
2675        self,
2676        child_player: Player,
2677        parent_player: Player,
2678        parent_protocol_player: Player | None,
2679        parent_protocol_domain: str | None,
2680        protocol_members: list[str],
2681    ) -> tuple[bool, Player | None, str | None]:
2682        """
2683        Try to group the child through the output protocol it prefers in its player settings.
2684
2685        Only used when the group is not on a protocol yet or is already on that same protocol.
2686        Returns whether the child was grouped, together with the protocol player/domain the
2687        group is on: the child's preferred protocol may become the group's protocol.
2688
2689        :param child_player: The player being added to the group.
2690        :param parent_player: The parent player being joined.
2691        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2692        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2693        :param protocol_members: The protocol member list to append to.
2694        """
2695        child_protocol_id, protocol_domain = self._try_child_preferred_protocol(
2696            child_player, parent_player
2697        )
2698        if not (
2699            child_protocol_id
2700            and protocol_domain
2701            and (not parent_protocol_domain or protocol_domain == parent_protocol_domain)
2702        ):
2703            return False, parent_protocol_player, parent_protocol_domain
2704
2705        if not parent_protocol_player or parent_protocol_domain != protocol_domain:
2706            parent_protocol = parent_player.get_output_protocol_by_domain(protocol_domain)
2707            if parent_protocol:
2708                parent_protocol_player = parent_player.get_protocol_player(
2709                    parent_protocol.output_protocol_id
2710                )
2711                parent_protocol_domain = protocol_domain
2712        protocol_members.append(child_protocol_id)
2713        self.logger.log(
2714            VERBOSE_LOG_LEVEL,
2715            "Using child's preferred protocol %s for %s",
2716            protocol_domain,
2717            child_player.state.name,
2718        )
2719        return True, parent_protocol_player, parent_protocol_domain
2720
2721    def _try_group_via_active_protocol(
2722        self,
2723        child_player: Player,
2724        parent_protocol_player: Player | None,
2725        parent_protocol_domain: str | None,
2726        protocol_members: list[str],
2727    ) -> tuple[bool, Player | None, str | None]:
2728        """
2729        Try to group the child through the protocol the group is already on.
2730
2731        Returns whether the child was grouped, together with the protocol player/domain the
2732        group is on: the selection is dropped when that protocol cannot group members itself,
2733        so a later grouping method can select another one.
2734
2735        :param child_player: The player being added to the group.
2736        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2737        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2738        :param protocol_members: The protocol member list to append to.
2739        """
2740        if not parent_protocol_domain or not parent_protocol_player:
2741            return False, parent_protocol_player, parent_protocol_domain
2742
2743        if PlayerFeature.SET_MEMBERS not in parent_protocol_player.state.supported_features:
2744            self.logger.log(
2745                VERBOSE_LOG_LEVEL,
2746                "Parent's active protocol %s does not support SET_MEMBERS, "
2747                "will search for alternative",
2748                parent_protocol_domain,
2749            )
2750            # Drop the selection so a later grouping method can select a new protocol
2751            return False, None, None
2752
2753        child_protocol = child_player.get_output_protocol_by_domain(parent_protocol_domain)
2754        if not child_protocol or not child_protocol.available:
2755            return False, parent_protocol_player, parent_protocol_domain
2756
2757        # For native protocol players, use the child's player_id directly
2758        # (e.g., a native sendspin web player IS the protocol player)
2759        child_protocol_id = (
2760            child_player.player_id
2761            if child_protocol.is_native
2762            else child_protocol.output_protocol_id
2763        )
2764        protocol_members.append(child_protocol_id)
2765        self.logger.log(
2766            VERBOSE_LOG_LEVEL,
2767            "Using parent's active protocol %s for %s",
2768            parent_protocol_domain,
2769            child_player.state.name,
2770        )
2771        return True, parent_protocol_player, parent_protocol_domain
2772
2773    def _try_group_via_common_protocol(
2774        self,
2775        child_player: Player,
2776        parent_player: Player,
2777        parent_protocol_player: Player | None,
2778        parent_protocol_domain: str | None,
2779        protocol_members: list[str],
2780    ) -> tuple[bool, Player | None, str | None]:
2781        """
2782        Try to group the child through a protocol both players share.
2783
2784        Returns whether the child was grouped, together with the protocol player/domain the
2785        group is on: the shared protocol may become the group's protocol.
2786
2787        :param child_player: The player being added to the group.
2788        :param parent_player: The parent player being joined.
2789        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2790        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2791        :param protocol_members: The protocol member list to append to.
2792        """
2793        parent_protocol, child_protocol = self._try_find_common_protocol(
2794            child_player, parent_player
2795        )
2796        if not parent_protocol or not child_protocol:
2797            return False, parent_protocol_player, parent_protocol_domain
2798
2799        if not parent_protocol_player or parent_protocol_domain != parent_protocol.protocol_domain:
2800            parent_protocol_player = parent_player.get_protocol_player(
2801                parent_protocol.output_protocol_id
2802            )
2803            if parent_protocol_player:
2804                parent_protocol_domain = parent_protocol_player.provider.domain
2805        # For native protocol players, use the child's player_id directly
2806        child_protocol_id = (
2807            child_player.player_id
2808            if child_protocol.is_native
2809            else child_protocol.output_protocol_id
2810        )
2811        protocol_members.append(child_protocol_id)
2812        self.logger.log(
2813            VERBOSE_LOG_LEVEL,
2814            "Selected common protocol %s for grouping %s with %s",
2815            parent_protocol.protocol_domain,
2816            child_player.state.name,
2817            parent_player.state.name,
2818        )
2819        return True, parent_protocol_player, parent_protocol_domain
2820
2821    async def _forward_protocol_set_members(
2822        self,
2823        parent_player: Player,
2824        parent_protocol_player: Player,
2825        protocol_members_to_add: list[str],
2826        protocol_members_to_remove: list[str],
2827    ) -> None:
2828        """
2829        Forward protocol members to protocol player's set_members and manage active output protocol.
2830
2831        :param parent_player: The parent player (native/universal).
2832        :param parent_protocol_player: The protocol player to forward commands to.
2833        :param protocol_members_to_add: Protocol player IDs to add.
2834        :param protocol_members_to_remove: Protocol player IDs to remove.
2835        """
2836        filtered_protocol_add = self._filter_protocol_members(
2837            protocol_members_to_add, parent_protocol_player
2838        )
2839        filtered_protocol_remove = self._filter_protocol_members(
2840            protocol_members_to_remove, parent_protocol_player
2841        )
2842        self.logger.debug(
2843            "Protocol grouping on %s: filtered_add=%s, filtered_remove=%s",
2844            parent_protocol_player.state.name,
2845            filtered_protocol_add,
2846            filtered_protocol_remove,
2847        )
2848
2849        if not filtered_protocol_add and not filtered_protocol_remove:
2850            return
2851
2852        # Safety check: verify protocol player supports SET_MEMBERS
2853        if PlayerFeature.SET_MEMBERS not in parent_protocol_player.state.supported_features:
2854            self.logger.error(
2855                "Protocol player %s does not support SET_MEMBERS, cannot perform grouping. "
2856                "This should have been caught earlier in the flow.",
2857                parent_protocol_player.state.name,
2858            )
2859            return
2860
2861        # Members that ride the parent's own stream are stranded by the protocol switch below,
2862        # so they join the protocol group in this very same call and their native session is
2863        # torn down afterwards.
2864        stranded_native_members = (
2865            self._migrate_stranded_native_members(
2866                parent_player, parent_protocol_player, filtered_protocol_add
2867            )
2868            if filtered_protocol_add
2869            else []
2870        )
2871
2872        # This runs before set_members because a member's own stream starts inside that call
2873        # and the provider resolves the member's volume control as it starts: unless its parent
2874        # already points at this protocol, that resolution picks a sibling interface of the same
2875        # device (e.g. its cast side) over the one carrying the audio.
2876        self._activate_protocol_on_added_children(filtered_protocol_add)
2877
2878        self.logger.debug(
2879            "Calling set_members on protocol player %s with add=%s, remove=%s",
2880            parent_protocol_player.state.name,
2881            filtered_protocol_add,
2882            filtered_protocol_remove,
2883        )
2884        await parent_protocol_player.set_members(
2885            player_ids_to_add=filtered_protocol_add or None,
2886            player_ids_to_remove=filtered_protocol_remove or None,
2887        )
2888
2889        if filtered_protocol_add:
2890            await self._activate_group_output_protocol(
2891                parent_player, parent_protocol_player, stranded_native_members
2892            )
2893
2894        self.logger.debug(
2895            "After set_members, protocol player %s state: group_members=%s, synced_to=%s",
2896            parent_protocol_player.state.name,
2897            parent_protocol_player.group_members,
2898            parent_protocol_player.synced_to,
2899        )
2900
2901    def _activate_protocol_on_added_children(self, protocol_member_ids: list[str]) -> None:
2902        """
2903        Point the parent of each given protocol member at the protocol carrying the group audio.
2904
2905        :param protocol_member_ids: The protocol player IDs joining the group.
2906        """
2907        for child_protocol_id in protocol_member_ids:
2908            if not (child_protocol := self.get_player(child_protocol_id)):
2909                continue
2910            if not child_protocol.protocol_parent_id:
2911                continue
2912            if not (child_player := self.get_player(child_protocol.protocol_parent_id)):
2913                continue
2914            if child_player.active_output_protocol == child_protocol_id:
2915                continue
2916            self.logger.debug(
2917                "Setting active output protocol on child %s to %s",
2918                child_player.state.name,
2919                child_protocol_id,
2920            )
2921            child_player.set_active_output_protocol(child_protocol_id)
2922
2923    async def _activate_group_output_protocol(
2924        self,
2925        parent_player: Player,
2926        parent_protocol_player: Player,
2927        stranded_native_members: list[str],
2928    ) -> None:
2929        """
2930        Mark the given protocol as the parent's output and hand the playback over to it.
2931
2932        The handover only runs when the parent is actually switching protocol while it is
2933        rendering; playback is resumed only for a parent that was playing, so adding a member
2934        never starts playback on its own.
2935
2936        :param parent_player: The parent player that just gained protocol members.
2937        :param parent_protocol_player: The protocol player the members joined.
2938        :param stranded_native_members: The members left without a stream by the switch.
2939        """
2940        previous_protocol = parent_player.active_output_protocol
2941        was_playing = parent_player.state.playback_state == PlaybackState.PLAYING
2942        # A paused player still holds its output, so the handover has to run for it too.
2943        was_rendering = was_playing or parent_player.state.playback_state == PlaybackState.PAUSED
2944
2945        # Native protocol: parent_protocol_player is the same as parent_player
2946        is_native_protocol = parent_protocol_player.player_id == parent_player.player_id
2947        already_using_native = previous_protocol in (None, "native")
2948        already_using_this_protocol = previous_protocol == parent_protocol_player.player_id
2949        switching_protocols = not (
2950            (is_native_protocol and already_using_native) or already_using_this_protocol
2951        )
2952
2953        self.logger.debug(
2954            "Protocol grouping: is_native=%s, already_native=%s, already_this=%s, "
2955            "switching=%s, was_rendering=%s",
2956            is_native_protocol,
2957            already_using_native,
2958            already_using_this_protocol,
2959            switching_protocols,
2960            was_rendering,
2961        )
2962
2963        if not (is_native_protocol and already_using_native):
2964            parent_player.set_active_output_protocol(parent_protocol_player.player_id)
2965
2966        if not (was_rendering and switching_protocols):
2967            return
2968
2969        self.logger.info(
2970            "Handing the output of %s over to the %s protocol%s",
2971            parent_player.state.name,
2972            parent_protocol_player.provider.domain,
2973            " and resuming playback" if was_playing else "",
2974        )
2975        if stranded_native_members:
2976            await self._stop_native_session(
2977                parent_player, parent_protocol_player, stranded_native_members
2978            )
2979        old_parent_members = await self._stop_previous_protocol(
2980            parent_player, parent_protocol_player, previous_protocol
2981        )
2982        if was_playing:
2983            await self.mass.players.cmd_resume(parent_player.player_id)
2984        if old_parent_members:
2985            self.logger.debug(
2986                "Re-adding migrated members %s to %s on new protocol",
2987                old_parent_members,
2988                parent_player.state.name,
2989            )
2990            # Use internal handler because we are already inside a
2991            # _handle_set_members call chain that holds the play lock.
2992            await self.mass.players._handle_set_members(
2993                parent_player,
2994                player_ids_to_add=old_parent_members,
2995            )
2996
2997    async def _stop_previous_protocol(
2998        self,
2999        parent_player: Player,
3000        parent_protocol_player: Player,
3001        previous_protocol: str | None,
3002    ) -> list[str]:
3003        """
3004        Stop the protocol player the parent was rendering through and return its members.
3005
3006        The returned IDs are parent player IDs, so the caller can re-add them to the group
3007        once the new protocol carries the audio. Empty if there is nothing to hand over.
3008
3009        :param parent_player: The parent player that is switching protocol.
3010        :param parent_protocol_player: The protocol player taking the output over.
3011        :param previous_protocol: The parent's previous active output protocol, if any.
3012        """
3013        if previous_protocol in (None, "native"):
3014            return []
3015        if not (old_protocol_player := self.get_player(previous_protocol)):
3016            return []
3017        if old_protocol_player.player_id == parent_protocol_player.player_id:
3018            return []
3019        # Translate the old protocol's child members back to parent player IDs
3020        old_parent_members: list[str] = []
3021        for member_id in old_protocol_player.group_members:
3022            if member_id == old_protocol_player.player_id:
3023                continue
3024            if not (member_player := self.get_player(member_id)):
3025                continue
3026            parent_id = member_player.protocol_parent_id or member_id
3027            if parent_id != parent_player.player_id:
3028                old_parent_members.append(parent_id)
3029        self.logger.debug(
3030            "Stopping old protocol player %s before switching to %s, migrating members: %s",
3031            old_protocol_player.state.name,
3032            parent_protocol_player.state.name,
3033            old_parent_members,
3034        )
3035        # Use internal handler to stop the specific protocol player,
3036        # bypassing group/sync redirect and queue redirect logic.
3037        await self.mass.players._handle_cmd_stop(old_protocol_player.player_id)
3038        return old_parent_members
3039