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._repoint_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 all protocol links from universal player to native player
1043            for linked in list(player.linked_output_protocols):
1044                if protocol_player := self.get_player(linked.output_protocol_id):
1045                    protocol_player.set_protocol_parent_id(None)
1046                    domain = linked.protocol_domain or protocol_player.provider.domain
1047                    self._add_protocol_link(native_player, protocol_player, domain)
1048                    if protocol_player.protocol_parent_id != native_player.player_id:
1049                        # Link refused, keep the protocol owned by the universal player.
1050                        protocol_player.set_protocol_parent_id(player.player_id)
1051                        refused_protocol_ids.add(protocol_player.player_id)
1052                        continue
1053                    protocol_player.refresh_state()
1054                    moved_protocol_ids.add(protocol_player.player_id)
1055
1056            # A refused link leaves the universal player in charge, so only hand over what
1057            # actually moved: ownership that exists in config alone stays with it, which
1058            # keeps a protocol derived from a refused one with the parent it will link to.
1059            migrated_protocol_ids = (
1060                moved_protocol_ids if refused_protocol_ids else known_protocol_ids
1061            )
1062            # A device that kept its id across a type change lists itself here.
1063            # It must never become its own protocol, and it must also be dropped
1064            # from the obsolete universal player so the permanent cleanup below
1065            # doesn't treat it as an orphaned protocol (which would re-wrap the
1066            # native player in a fresh universal player).
1067            migrated_protocol_ids.discard(native_player.player_id)
1068            self._migrate_protocol_ids_to_parent(native_player, migrated_protocol_ids)
1069            self._remove_protocol_ids_from_parent(
1070                player, migrated_protocol_ids | {native_player.player_id}
1071            )
1072            native_player.refresh_state()
1073
1074            if refused_protocol_ids:
1075                # Registered protocols that the native player refused remain on the wrapper.
1076                continue
1077
1078            # Carry over the user's configuration and re-point group memberships
1079            # before the permanent removal below deletes the universal player's config
1080            self._migrate_universal_player_config(player.player_id, native_player.player_id)
1081            self._repoint_group_memberships(player.player_id, native_player.player_id)
1082
1083            # Stop playback and remove the now-obsolete universal player
1084            self.mass.create_task(self._stop_and_unregister(player, native_player.player_id))
1085
1086    def _migrate_universal_player_config(self, universal_id: str, native_id: str) -> None:
1087        """
1088        Carry over user-set configuration from a replaced universal player.
1089
1090        Copies the custom display name, player config values, DSP settings and
1091        per-queue settings of the (obsolete) universal player onto the native
1092        player that replaces it, without overwriting values explicitly set on
1093        the native player itself. Must be called while the universal player's
1094        config still exists, as the permanent removal deletes it.
1095
1096        :param universal_id: Player id of the obsolete universal player being replaced.
1097        :param native_id: Player id of the native player that replaces it.
1098        """
1099        source_raw = self.mass.config.get(f"{CONF_PLAYERS}/{universal_id}")
1100        source_raw = source_raw if isinstance(source_raw, dict) else {}
1101        target_key = f"{CONF_PLAYERS}/{native_id}"
1102        target_raw = self.mass.config.get(target_key)
1103        target_raw = target_raw if isinstance(target_raw, dict) else {}
1104        player_config_changed = False
1105
1106        # only carry an actual user rename, not the auto-generated default name;
1107        # likewise a name on the native player only counts as a user override when
1108        # it differs from the default name
1109        custom_name = source_raw.get("name")
1110        target_name = target_raw.get("name")
1111        target_has_custom_name = bool(target_name) and target_name != target_raw.get("default_name")
1112        if (
1113            custom_name
1114            and custom_name != source_raw.get("default_name")
1115            and not target_has_custom_name
1116        ):
1117            self.mass.config.set(f"{target_key}/name", custom_name)
1118            player_config_changed = True
1119
1120        source_values = source_raw.get("values")
1121        source_values = source_values if isinstance(source_values, dict) else {}
1122        target_values = target_raw.get("values")
1123        target_values = target_values if isinstance(target_values, dict) else {}
1124        for key, value in source_values.items():
1125            if key in UNIVERSAL_PLAYER_INTERNAL_CONF_KEYS:
1126                continue
1127            if CONF_PROTOCOL_KEY_SPLITTER in key:
1128                # stale virtual mirror of a protocol player's own config
1129                continue
1130            if key in target_values:
1131                continue
1132            self.mass.config.set(f"{target_key}/values/{key}", deepcopy(value))
1133            player_config_changed = True
1134
1135        # DSP settings follow wholesale, unless the native player has its own
1136        dsp_changed = False
1137        source_dsp = self.mass.config.get(f"{CONF_PLAYER_DSP}/{universal_id}")
1138        if source_dsp and not self.mass.config.get(f"{CONF_PLAYER_DSP}/{native_id}"):
1139            self.mass.config.set(f"{CONF_PLAYER_DSP}/{native_id}", deepcopy(source_dsp))
1140            dsp_changed = True
1141
1142        queue_changed = self._migrate_universal_queue_config(universal_id, native_id)
1143
1144        if not (player_config_changed or dsp_changed or queue_changed):
1145            return
1146        self.logger.info(
1147            "Carried over configuration of universal player %s to %s", universal_id, native_id
1148        )
1149        if player_config_changed:
1150            # the native player's in-place config was loaded before the carry-over,
1151            # so reload it to make the migrated values (e.g. custom name) effective
1152            self.mass.create_task(self._reapply_player_config(native_id))
1153
1154    def _migrate_universal_queue_config(self, universal_id: str, native_id: str) -> bool:
1155        """
1156        Move the per-queue settings of a replaced universal player to its replacement.
1157
1158        Queue ids equal player ids, so the source entry is removed once it is carried over.
1159
1160        :param universal_id: Player id of the obsolete universal player.
1161        :param native_id: Player id of the native player that replaces it.
1162        :return: True if any queue setting was carried over.
1163        """
1164        queue_changed = False
1165        source_queue_raw = self.mass.config.get(f"{CONF_PLAYER_QUEUES}/{universal_id}")
1166        source_queue_raw = source_queue_raw if isinstance(source_queue_raw, dict) else None
1167        if source_queue_values := (source_queue_raw or {}).get("values"):
1168            target_queue_key = f"{CONF_PLAYER_QUEUES}/{native_id}"
1169            target_queue_raw = self.mass.config.get(target_queue_key)
1170            target_queue_raw = (
1171                deepcopy(target_queue_raw) if isinstance(target_queue_raw, dict) else {}
1172            )
1173            target_queue_values = target_queue_raw.setdefault("values", {})
1174            for key, value in source_queue_values.items():
1175                if key in target_queue_values:
1176                    continue
1177                target_queue_values[key] = deepcopy(value)
1178                queue_changed = True
1179            if queue_changed:
1180                target_queue_raw["queue_id"] = native_id
1181                self.mass.config.set(target_queue_key, target_queue_raw)
1182        if source_queue_raw is not None:
1183            self.mass.config.remove(f"{CONF_PLAYER_QUEUES}/{universal_id}")
1184        return queue_changed
1185
1186    async def _reapply_player_config(self, player_id: str) -> None:
1187        """Reload the stored config onto a registered player and refresh its state."""
1188        if not (player := self.get_player(player_id)):
1189            return
1190        config = await self.mass.config.get_player_config(player_id)
1191        player.set_config(config)
1192        player.update_state()
1193        self.mass.signal_event(EventType.PLAYER_CONFIG_UPDATED, object_id=player_id, data=config)
1194
1195    def _repoint_group_memberships(self, old_player_id: str, new_player_id: str) -> None:
1196        """
1197        Re-point group memberships from a removed player to its successor.
1198
1199        When a universal player is replaced by a native player or merged into
1200        another universal player, other players that list the removed player as
1201        a group member (or allowed member) must follow its successor so those
1202        memberships are not silently lost. Updates the persisted config and keeps
1203        any registered player whose membership changed in sync.
1204
1205        :param old_player_id: Player id that is being removed.
1206        :param new_player_id: Player id that replaces it.
1207        """
1208        all_player_configs = self.mass.config.get(CONF_PLAYERS, {})
1209        if not isinstance(all_player_configs, dict):
1210            return
1211        for other_id, other_cfg in all_player_configs.items():
1212            if not isinstance(other_cfg, dict):
1213                continue
1214            other_values = other_cfg.get("values")
1215            if not isinstance(other_values, dict):
1216                continue
1217            for key in (CONF_GROUP_MEMBERS, CONF_ALLOWED_MEMBERS):
1218                members = other_values.get(key)
1219                if not isinstance(members, list) or old_player_id not in members:
1220                    continue
1221                new_members: list[str] = []
1222                for member_id in members:
1223                    resolved = new_player_id if member_id == old_player_id else member_id
1224                    if resolved not in new_members:
1225                        new_members.append(resolved)
1226                self.mass.config.set(f"{CONF_PLAYERS}/{other_id}/values/{key}", new_members)
1227                # keep a registered player's in-place config copy and state in sync
1228                if other_player := self.get_player(other_id):
1229                    if entry := other_player.config.values.get(key):
1230                        entry.value = new_members
1231                    other_player.refresh_state()
1232
1233    async def _stop_and_unregister(self, player: Player, replacement_player_id: str) -> None:
1234        """
1235        Stop active playback on a player and then permanently unregister it.
1236
1237        Used when an obsolete universal player is replaced or merged away: while
1238        it is not idle its protocol child keeps playing the dead queue's stream
1239        until the buffer drains, so playback is stopped first. Queue ownership is
1240        intentionally not transferred.
1241
1242        :param player: The obsolete player to stop and permanently remove.
1243        :param replacement_player_id: Player ID that takes the obsolete player's place.
1244        """
1245        if player.playback_state != PlaybackState.IDLE:
1246            with suppress(PlayerCommandFailed, PlayerUnavailableError):
1247                await self.mass.player_queues.stop(player.player_id)
1248        await self.unregister(
1249            player.player_id, permanent=True, replacement_player_id=replacement_player_id
1250        )
1251
1252    def _parent_has_active_protocol_from_domain(
1253        self, parent: Player, domain: str, exclude_player_id: str | None = None
1254    ) -> bool:
1255        """
1256        Check if a parent already has an active (registered) protocol player from a given domain.
1257
1258        This prevents a second protocol player of the same domain (e.g., a second AirPlay
1259        instance on the same host) from replacing the first one's link on the same parent.
1260
1261        :param parent: The parent player to check.
1262        :param domain: The protocol domain to check for (e.g., "airplay", "dlna").
1263        :param exclude_player_id: Optional player ID to exclude from the check
1264            (used when checking if a player's own domain is already linked).
1265        """
1266        for link in parent.linked_output_protocols:
1267            if link.protocol_domain != domain:
1268                continue
1269            if exclude_player_id and link.output_protocol_id == exclude_player_id:
1270                continue
1271            # A registered player from this domain blocks the link, even if unavailable.
1272            # Being offline doesn't make it a different device — it's still occupying
1273            # this domain slot. The provider should remove stale players explicitly.
1274            if self.get_player(link.output_protocol_id):
1275                return True
1276        return False
1277
1278    def _add_protocol_link(
1279        self, native_player: Player, protocol_player: Player, protocol_domain: str
1280    ) -> None:
1281        """Add a protocol link from native player to protocol player."""
1282        # Never link a player to itself (hides it as its own protocol child).
1283        if native_player.player_id == protocol_player.player_id:
1284            return
1285        # Guard: refuse to replace an existing active link from the same domain.
1286        # This prevents a second instance of the same protocol (e.g., two AirPlay
1287        # instances on the same host) from silently replacing the first one.
1288        if self._parent_has_active_protocol_from_domain(
1289            native_player, protocol_domain, exclude_player_id=protocol_player.player_id
1290        ):
1291            self.logger.debug(
1292                "Refusing to link %s to %s: parent already has an active %s link",
1293                protocol_player.player_id,
1294                native_player.player_id,
1295                protocol_domain,
1296            )
1297            return
1298
1299        # Remove any existing link for the same protocol domain
1300        updated_protocols = [
1301            link
1302            for link in native_player.linked_output_protocols
1303            if link.protocol_domain != protocol_domain
1304        ]
1305
1306        # Get priority for this protocol
1307        priority = PROTOCOL_PRIORITY.get(protocol_domain, 100)
1308
1309        # Derived transports (e.g. a Sendspin bridge riding on an AirPlay player)
1310        # reference the base output they run on top of; "native" when they ride
1311        # on the parent player itself
1312        derived_from = protocol_player.underlying_player_id
1313        if derived_from == native_player.player_id:
1314            derived_from = "native"
1315
1316        # Add the new link
1317        updated_protocols.append(
1318            LinkedOutputProtocol(
1319                output_protocol_id=protocol_player.player_id,
1320                protocol_domain=protocol_domain,
1321                priority=priority,
1322                derived_from=derived_from,
1323            )
1324        )
1325        native_player.set_linked_output_protocols(updated_protocols)
1326
1327        # Set protocol player's parent
1328        protocol_player.set_protocol_parent_id(native_player.player_id)
1329
1330        # Persist linked protocol IDs to config for fast restart
1331        # (only for non-universal players, as universal players handle this themselves)
1332        if native_player.provider.domain != "universal_player":
1333            self._save_linked_protocol_ids(native_player)
1334        # Always save the parent ID on the protocol player for reverse lookup on restart
1335        # (needed for both native and universal parents to enable fast restore)
1336        self._save_protocol_parent_id(protocol_player.player_id, native_player.player_id)
1337
1338        # The freshly linked player may have derived protocol players (e.g. a
1339        # Sendspin bridge riding on it) waiting to join the same parent.
1340        self._link_derived_protocols_of(protocol_player)
1341
1342    def _remove_protocol_link(
1343        self, native_player: Player, protocol_player_id: str, permanent: bool = False
1344    ) -> None:
1345        """
1346        Remove a protocol link.
1347
1348        :param native_player: The parent player to remove the link from.
1349        :param protocol_player_id: The protocol player ID to unlink.
1350        :param permanent: If True, also removes the protocol ID from the cached list.
1351            Use this when the protocol player config is being deleted. If False,
1352            the protocol ID remains in the cache so it can be shown as disabled
1353            and re-enabled later.
1354        """
1355        updated_protocols = [
1356            link
1357            for link in native_player.linked_output_protocols
1358            if link.output_protocol_id != protocol_player_id
1359        ]
1360        native_player.set_linked_output_protocols(updated_protocols)
1361
1362        # Clear parent reference on protocol player if it still exists
1363        if protocol_player := self.get_player(protocol_player_id):
1364            if protocol_player.protocol_parent_id == native_player.player_id:
1365                protocol_player.set_protocol_parent_id(None)
1366
1367        # Update persisted linked protocol IDs
1368        if native_player.provider.domain != "universal_player":
1369            if permanent:
1370                # Permanently remove from cache (player config is being deleted)
1371                self._remove_protocol_id_from_cache(native_player.player_id, protocol_player_id)
1372            # Note: we don't call _save_linked_protocol_ids here anymore for non-permanent
1373            # removals because the merge approach will preserve the ID in the cache
1374        # Always clear the cached parent ID (for both native and universal parents)
1375        self._clear_protocol_parent_id(protocol_player_id)
1376
1377    def _save_linked_protocol_ids(self, native_player: Player) -> None:
1378        """
1379        Save linked protocol IDs to config for persistence across restarts.
1380
1381        This method merges active protocol IDs with existing cached IDs to preserve
1382        disabled protocol players in the cache. This allows disabled protocols to be
1383        shown in the UI so they can be re-enabled.
1384        """
1385        conf_key = f"{CONF_PLAYERS}/{native_player.player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1386        # Get existing cached IDs to preserve disabled protocols
1387        existing_ids: list[str] = self.mass.config.get(conf_key, [])
1388        # Get currently active protocol IDs
1389        active_ids = {link.output_protocol_id for link in native_player.linked_output_protocols}
1390        # Merge: keep existing IDs and add any new active ones
1391        merged_ids = list(existing_ids)
1392        for protocol_id in active_ids:
1393            if protocol_id not in merged_ids:
1394                merged_ids.append(protocol_id)
1395        self.mass.config.set(conf_key, merged_ids)
1396
1397    def _get_cached_protocol_ids(self, player_id: str) -> list[str]:
1398        """Get cached linked protocol IDs from config."""
1399        conf_key = f"{CONF_PLAYERS}/{player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1400        result = self.mass.config.get(conf_key, [])
1401        return list(result) if result else []
1402
1403    def _remove_protocol_id_from_cache(
1404        self, parent_player_id: str, protocol_player_id: str
1405    ) -> None:
1406        """
1407        Permanently remove a protocol player ID from the cached linked protocol IDs.
1408
1409        Use this when a protocol player config is being deleted, not just disabled.
1410        """
1411        conf_key = f"{CONF_PLAYERS}/{parent_player_id}/values/{CONF_LINKED_PROTOCOL_IDS}"
1412        cached_ids: list[str] = self.mass.config.get(conf_key, [])
1413        if protocol_player_id in cached_ids:
1414            cached_ids.remove(protocol_player_id)
1415            self.mass.config.set(conf_key, cached_ids)
1416
1417    def _save_protocol_parent_id(self, protocol_player_id: str, parent_id: str) -> None:
1418        """Save the parent ID for a protocol player for persistence across restarts."""
1419        # Only save if the player config still exists to avoid creating partial entries
1420        if not self.mass.config.get(f"{CONF_PLAYERS}/{protocol_player_id}"):
1421            return
1422        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1423        self.mass.config.set(conf_key, parent_id)
1424
1425    def _save_underlying_player_id(self, player: Player) -> None:
1426        """
1427        Persist the derived-transport edge of a player to config.
1428
1429        Allows the edge to be resolved (e.g. by the config UI) even while the
1430        player is not registered. Clears a previously persisted edge when the
1431        player is no longer derived (e.g. a bridge client turned web player).
1432        """
1433        # Only save if the player config still exists to avoid creating partial entries
1434        if not self.mass.config.get(f"{CONF_PLAYERS}/{player.player_id}"):
1435            return
1436        conf_key = f"{CONF_PLAYERS}/{player.player_id}/values/{CONF_UNDERLYING_PLAYER_ID}"
1437        if player.underlying_player_id:
1438            self.mass.config.set(conf_key, player.underlying_player_id)
1439        elif self.mass.config.get(conf_key) is not None:
1440            self.mass.config.set(conf_key, None)
1441
1442    def _get_cached_protocol_parent_id(self, protocol_player_id: str) -> str | None:
1443        """Get cached parent ID for a protocol player from config."""
1444        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1445        result = self.mass.config.get(conf_key, None)
1446        return str(result) if result else None
1447
1448    def _clear_protocol_parent_id(self, protocol_player_id: str) -> None:
1449        """Clear the cached parent ID for a protocol player."""
1450        # Only clear if the player config still exists to avoid creating partial entries
1451        if not self.mass.config.get(f"{CONF_PLAYERS}/{protocol_player_id}"):
1452            return
1453        conf_key = f"{CONF_PLAYERS}/{protocol_player_id}/values/{CONF_PROTOCOL_PARENT_ID}"
1454        self.mass.config.set(conf_key, None)
1455
1456    def _recover_cached_protocol_links(self, native_player: Player) -> None:
1457        """
1458        Recover protocol links from config for disabled/missing protocols.
1459
1460        This ensures that disabled protocols show up in the output_protocols list
1461        so they can be re-enabled by the user. It also handles the case where
1462        protocol players haven't registered yet during startup.
1463        """
1464        # Get currently linked protocol IDs
1465        linked_protocol_ids = {
1466            link.output_protocol_id for link in native_player.linked_output_protocols
1467        }
1468
1469        # Get cached protocol IDs from config (includes protocols that were explicitly linked)
1470        cached_protocol_ids = self._get_cached_protocol_ids(native_player.player_id)
1471
1472        # Also check all protocol players that have protocol_parent_id pointing to this player
1473        # (this handles disabled protocols that may not be in linked_protocol_ids)
1474        all_player_configs = self.mass.config.get(CONF_PLAYERS, {})
1475        for protocol_id, protocol_config in all_player_configs.items():
1476            # Skip if not a protocol player
1477            if protocol_config.get("player_type") != "protocol":
1478                continue
1479            # Check if this protocol has a parent_id pointing to this native player
1480            protocol_values = protocol_config.get("values", {})
1481            protocol_parent_id = protocol_values.get(CONF_PROTOCOL_PARENT_ID)
1482            if protocol_parent_id == native_player.player_id:
1483                if protocol_id not in cached_protocol_ids:
1484                    cached_protocol_ids.append(protocol_id)
1485
1486        if not cached_protocol_ids:
1487            return
1488
1489        # Add link entries for any cached protocols that aren't currently linked
1490        updated_protocols = list(native_player.linked_output_protocols)
1491        for protocol_id in cached_protocol_ids:
1492            if protocol_id in linked_protocol_ids:
1493                continue  # Already linked
1494
1495            # Get protocol player config to determine the protocol domain
1496            protocol_config = self.mass.config.get(f"{CONF_PLAYERS}/{protocol_id}")
1497            if not protocol_config:
1498                continue
1499
1500            # Determine protocol domain from provider
1501            protocol_provider: str = protocol_config.get("provider")
1502            if not protocol_provider:
1503                continue
1504
1505            # Extract domain from provider instance_id (e.g., "airplay--uuid" -> "airplay")
1506            protocol_domain = protocol_provider.split("--", maxsplit=1)[0]
1507
1508            # Skip if parent already has a link from this domain
1509            existing_domains = {link.protocol_domain for link in updated_protocols}
1510            if protocol_domain in existing_domains:
1511                continue
1512
1513            # Get priority for this protocol
1514            priority = PROTOCOL_PRIORITY.get(protocol_domain, 100)
1515
1516            # Resolve the derived-transport edge from the live player when
1517            # registered, else from the persisted edge in config
1518            protocol_player = self.get_player(protocol_id)
1519            derived_from = (
1520                protocol_player.underlying_player_id
1521                if protocol_player
1522                else protocol_config.get("values", {}).get(CONF_UNDERLYING_PLAYER_ID)
1523            )
1524            if derived_from == native_player.player_id:
1525                derived_from = "native"
1526
1527            updated_protocols.append(
1528                LinkedOutputProtocol(
1529                    output_protocol_id=protocol_id,
1530                    protocol_domain=protocol_domain,
1531                    priority=priority,
1532                    derived_from=derived_from,
1533                )
1534            )
1535            self.logger.debug(
1536                "Recovered cached protocol link %s -> %s",
1537                native_player.player_id,
1538                protocol_id,
1539            )
1540
1541        if len(updated_protocols) != len(native_player.linked_output_protocols):
1542            native_player.set_linked_output_protocols(updated_protocols)
1543
1544    def _cleanup_protocol_links(self, player: Player) -> None:
1545        """Clean up protocol links when a player is permanently removed."""
1546        if player.state.type == PlayerType.PROTOCOL:
1547            # Protocol player being removed: remove link from parent
1548            if parent_id := player.protocol_parent_id:
1549                if parent_player := self.get_player(parent_id):
1550                    # Use permanent=True to also remove from cached protocol IDs
1551                    self._remove_protocol_link(parent_player, player.player_id, permanent=True)
1552                    if (
1553                        parent_player.provider.domain == "universal_player"
1554                        and len(parent_player.linked_output_protocols) == 0
1555                    ):
1556                        # No protocols left - the universal player has nothing to play
1557                        # on. Its config is deliberately kept: the player id is opaque
1558                        # and cannot be recreated, so deleting it here would orphan the
1559                        # entities API consumers bound to it. Only an explicit removal
1560                        # by the user deletes a universal player for good.
1561                        self.logger.info(
1562                            "Universal player %s has no protocols left",
1563                            parent_id,
1564                        )
1565                        self.mass.create_task(
1566                            self.mass.players.unregister(parent_id, permanent=False)
1567                        )
1568                    else:
1569                        parent_player.refresh_state()
1570                else:
1571                    # Parent not registered yet — still purge the cached id
1572                    self._remove_protocol_id_from_cache(parent_id, player.player_id)
1573        else:
1574            # Native/universal player being removed: handle all linked protocol players.
1575            # Collect all known protocol IDs from both active links and cached state,
1576            # since disabled/inactive protocols may only exist in the cached parent data.
1577            all_protocol_ids = set(self._get_known_protocol_ids(player))
1578            for protocol_id in all_protocol_ids:
1579                if protocol_player := self.get_player(protocol_id):
1580                    # Protocol player is available: clear parent and schedule re-evaluation
1581                    # so it can be matched to a new parent or a new universal player
1582                    self.logger.debug(
1583                        "Player %s removed - scheduling evaluation for protocol %s",
1584                        player.player_id,
1585                        protocol_id,
1586                    )
1587                    self._detach_protocol_child(protocol_player)
1588                else:
1589                    # Clear cached parent ID in config so protocol won't try to
1590                    # restore a link to the deleted player on next restart
1591                    self._clear_protocol_parent_id(protocol_id)
1592                    # Protocol player is not registered yet — it may still be
1593                    # mid-discovery (e.g., DLNA connecting via SSDP). Don't delete
1594                    # its config as that would cause a KeyError when it finishes
1595                    # registering. Stale configs are harmless and get cleaned up
1596                    # naturally on subsequent restarts.
1597                    self.logger.debug(
1598                        "Player %s removed - protocol %s not registered, skipping cleanup",
1599                        player.player_id,
1600                        protocol_id,
1601                    )
1602
1603    def _cleanup_player_type_transition(self, existing: Player) -> None:
1604        """
1605        Release the protocol topology a player owned before its type changed.
1606
1607        :param existing: The registered player instance, still reporting its previous type.
1608        """
1609        if existing.state.type == PlayerType.PROTOCOL:
1610            # a provider may announce the new type with the live parent link already
1611            # dropped, so fall back to the persisted one to still reach the parent
1612            parent_id = existing.protocol_parent_id or self._get_cached_protocol_parent_id(
1613                existing.player_id
1614            )
1615            if not parent_id:
1616                return
1617            parent = self.get_player(parent_id)
1618            if parent is not None and parent.provider.domain == "universal_player":
1619                # drop only the active edge and leave the rest to the link evaluation,
1620                # which replaces the wrapper with this player: a leftover edge makes it
1621                # hand the player over to itself, which it refuses, abandoning the swap
1622                self._remove_protocol_link(parent, existing.player_id)
1623                return
1624            existing.set_protocol_parent_id(parent_id)
1625            # unlink at the parent and drop the persisted parent id, which would
1626            # otherwise heal the player's type back to protocol
1627            self._cleanup_protocol_links(existing)
1628            # a player leaving the protocol role has no parent, also when that parent
1629            # is not registered (anymore) and only the cached link could be cleaned up
1630            existing.set_protocol_parent_id(None)
1631            return
1632        # the player becomes a child itself: detach the protocol players it owned so they
1633        # can find a new parent, then give up their ownership in its (kept) config - the
1634        # reverse of the removal path, which drops the ownership before the detach
1635        protocol_ids = set(self._get_known_protocol_ids(existing))
1636        self._cleanup_protocol_links(existing)
1637        self._remove_protocol_ids_from_parent(existing, protocol_ids)
1638
1639    def _detach_protocol_children(self, parent_id: str) -> None:
1640        """
1641        Detach the registered protocol players of a parent player that is going away.
1642
1643        Covers the removal paths that don't unregister the parent first (e.g. its
1644        provider is unloaded), where the parent is not around anymore to enumerate
1645        its protocol players.
1646
1647        :param parent_id: Player id of the parent that is being removed.
1648        """
1649        for protocol_player in list(self._players.values()):
1650            if protocol_player.state.type != PlayerType.PROTOCOL:
1651                continue
1652            # a protocol player waiting for a parent that never registered only has
1653            # the link in its config, so fall back to the cached parent
1654            linked_parent_id = protocol_player.protocol_parent_id or (
1655                self._get_cached_protocol_parent_id(protocol_player.player_id)
1656            )
1657            if linked_parent_id != parent_id:
1658                continue
1659            self.logger.debug(
1660                "Player %s removed - scheduling evaluation for protocol %s",
1661                parent_id,
1662                protocol_player.player_id,
1663            )
1664            self._detach_protocol_child(protocol_player)
1665
1666    def _detach_protocol_child(self, protocol_player: Player) -> None:
1667        """Clear a protocol player's parent link and schedule a fresh evaluation."""
1668        self._clear_protocol_parent_id(protocol_player.player_id)
1669        protocol_player.set_protocol_parent_id(None)
1670        protocol_player.refresh_state()
1671        self._schedule_protocol_evaluation(protocol_player)
1672
1673    def _identifiers_match(
1674        self, player_a: Player, player_b: Player, protocol_domain: str = ""
1675    ) -> bool:
1676        """
1677        Check if identifiers match between two players.
1678
1679        Matching is done by comparing connection identifiers (MAC, serial, UUID).
1680        As a last resort, IP address is used when at least one player has a
1681        locally-administered MAC, indicating the device uses MAC randomization
1682        and ARP could not resolve the real hardware address.
1683
1684        Invalid identifiers (e.g., 00:00:00:00:00:00 MAC addresses) are filtered out
1685        to prevent false matches between unrelated devices.
1686        """
1687        identifiers_a = player_a.device_info.identifiers
1688        identifiers_b = player_b.device_info.identifiers
1689
1690        # Check identifiers in order of reliability
1691        # MAC_ADDRESS > SERIAL_NUMBER > UUID > CAST_UUID > AIRPLAY_ID
1692        for conn_type in (
1693            IdentifierType.MAC_ADDRESS,
1694            IdentifierType.SERIAL_NUMBER,
1695            IdentifierType.UUID,
1696            IdentifierType.CAST_UUID,
1697            IdentifierType.AIRPLAY_ID,
1698        ):
1699            val_a = identifiers_a.get(conn_type)
1700            val_b = identifiers_b.get(conn_type)
1701
1702            if not val_a or not val_b:
1703                continue
1704
1705            # Filter out invalid MAC addresses (00:00:00:00:00:00, ff:ff:ff:ff:ff:ff)
1706            if conn_type == IdentifierType.MAC_ADDRESS:
1707                if not is_valid_mac_address(val_a) or not is_valid_mac_address(val_b):
1708                    self.logger.log(
1709                        VERBOSE_LOG_LEVEL,
1710                        "Skipping invalid MAC address for matching: %s=%s, %s=%s",
1711                        player_a.display_name,
1712                        val_a,
1713                        player_b.display_name,
1714                        val_b,
1715                    )
1716                    continue
1717
1718            # Normalize values for comparison
1719            if conn_type == IdentifierType.MAC_ADDRESS:
1720                # Use MAC normalization that handles locally-administered bit differences
1721                # Some protocols (like AirPlay) report a locally-administered MAC variant
1722                # where bit 1 of the first octet is set (e.g., 54:78:... vs 56:78:...)
1723                val_a_norm = normalize_mac_for_matching(val_a)
1724                val_b_norm = normalize_mac_for_matching(val_b)
1725
1726                # Direct match on current MAC
1727                if val_a_norm == val_b_norm:
1728                    return True
1729
1730                # Multi-MAC matching: also check original reported MACs.
1731                # Devices with multiple interfaces (WiFi + Ethernet) may have ARP
1732                # resolve one MAC while the protocol reports a different one.
1733                macs_a = {val_a_norm}
1734                macs_b = {val_b_norm}
1735                reported_a = player_a.extra_data.get("reported_mac")
1736                reported_b = player_b.extra_data.get("reported_mac")
1737                if reported_a and is_valid_mac_address(reported_a):
1738                    macs_a.add(normalize_mac_for_matching(reported_a))
1739                if reported_b and is_valid_mac_address(reported_b):
1740                    macs_b.add(normalize_mac_for_matching(reported_b))
1741                if macs_a & macs_b:
1742                    return True
1743
1744                # No MAC match - continue to next identifier type
1745                continue
1746
1747            val_a_norm = val_a.lower().replace(":", "").replace("-", "")
1748            val_b_norm = val_b.lower().replace(":", "").replace("-", "")
1749
1750            # Direct match
1751            if val_a_norm == val_b_norm:
1752                return True
1753
1754            # Special case: Sonos UUID matching with DLNA _MR suffix
1755            # Sonos uses RINCON_xxx, DLNA uses RINCON_xxx_MR for Media Renderer
1756            if conn_type == IdentifierType.UUID:
1757                if val_b_norm.endswith("_mr") and val_b_norm[:-3] == val_a_norm:
1758                    return True
1759                if val_a_norm.endswith("_mr") and val_a_norm[:-3] == val_b_norm:
1760                    return True
1761
1762        # Last resort: IP-based matching.
1763        # Two players on the same IP are very likely the same physical device.
1764        # This handles two cases:
1765        # 1. MAC randomization: at least one player has no real MAC (LA or missing),
1766        #    so ARP couldn't resolve a usable address.
1767        # 2. Different MACs per protocol: some devices (e.g., Yamaha MusicCast) report
1768        #    different valid globally-unique MACs per protocol (DLNA vs AirPlay differ
1769        #    by 1 in the last octet). IP matching is safe here because two different
1770        #    devices on a LAN cannot share the same IP simultaneously.
1771        #    To avoid false positives between unrelated native players, this path
1772        #    requires at least one player to be a protocol or universal player.
1773        ip_a = identifiers_a.get(IdentifierType.IP_ADDRESS)
1774        ip_b = identifiers_b.get(IdentifierType.IP_ADDRESS)
1775        if ip_a and ip_b and ip_a == ip_b:
1776            mac_a = identifiers_a.get(IdentifierType.MAC_ADDRESS)
1777            mac_b = identifiers_b.get(IdentifierType.MAC_ADDRESS)
1778            a_is_real = (
1779                mac_a is not None
1780                and is_valid_mac_address(mac_a)
1781                and not is_locally_administered_mac(mac_a)
1782            )
1783            b_is_real = (
1784                mac_b is not None
1785                and is_valid_mac_address(mac_b)
1786                and not is_locally_administered_mac(mac_b)
1787            )
1788            # Case 1: at least one player has no real hardware MAC
1789            if not (a_is_real and b_is_real):
1790                return True
1791            # Case 2: both have real MACs but at least one is a protocol/universal player
1792            a_is_protocol = (
1793                player_a.type == PlayerType.PROTOCOL
1794                or player_a.provider.domain == "universal_player"
1795            )
1796            b_is_protocol = (
1797                player_b.type == PlayerType.PROTOCOL
1798                or player_b.provider.domain == "universal_player"
1799            )
1800            if a_is_protocol or b_is_protocol:
1801                return True
1802
1803        return False
1804
1805    def _select_best_output_protocol(self, player: Player) -> tuple[Player, OutputProtocol | None]:
1806        """
1807        Select the best available output protocol for a player.
1808
1809        Selection priority:
1810        1. Output protocol that is currently grouped/synced with other players.
1811        2. User's preferred output protocol (from player settings).
1812        3. Native playback (if player supports PLAY_MEDIA).
1813        4. The player's declared default output protocol domain, if available.
1814        5. Best available protocol by priority.
1815
1816        Returns tuple of (target_player, output_protocol).
1817        output_protocol is None when using native playback.
1818        """
1819        self.logger.log(
1820            VERBOSE_LOG_LEVEL,
1821            "Selecting output protocol for %s",
1822            player.state.name,
1823        )
1824
1825        # 1. Check if any output protocol is currently grouped
1826        for linked in player.linked_output_protocols:
1827            if protocol_player := self.get_player(linked.output_protocol_id):
1828                if protocol_player.available_for_playback and self._is_protocol_grouped(
1829                    protocol_player
1830                ):
1831                    self.logger.log(
1832                        VERBOSE_LOG_LEVEL,
1833                        "Selected protocol for %s: %s (grouped)",
1834                        player.state.name,
1835                        protocol_player.state.name,
1836                    )
1837                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1838
1839        # 2. Check for user's preferred output protocol.
1840        # The value is only stored while it differs from the entry's default: "native" when a
1841        # native output is available, otherwise "auto". A player without a native output (e.g. a
1842        # LinkPlay shell) therefore has no stored preference by default and gets its default
1843        # output domain applied in step 4.
1844        preferred = self.mass.config.get_raw_player_config_value(
1845            player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
1846        )
1847        if preferred and preferred != "auto":
1848            if preferred == "native":
1849                if PlayerFeature.PLAY_MEDIA in player.supported_features:
1850                    self.logger.log(
1851                        VERBOSE_LOG_LEVEL,
1852                        "Selected protocol for %s: native (user preference)",
1853                        player.state.name,
1854                    )
1855                    return player, None
1856            else:
1857                for linked in player.linked_output_protocols:
1858                    if linked.output_protocol_id == preferred:
1859                        if protocol_player := self.get_player(linked.output_protocol_id):
1860                            if protocol_player.available_for_playback:
1861                                self.logger.log(
1862                                    VERBOSE_LOG_LEVEL,
1863                                    "Selected protocol for %s: %s (user preference)",
1864                                    player.state.name,
1865                                    protocol_player.state.name,
1866                                )
1867                                return protocol_player, player.get_linked_protocol(
1868                                    linked.output_protocol_id
1869                                )
1870                        break
1871
1872        # 3. Use native playback if available
1873        if PlayerFeature.PLAY_MEDIA in player.supported_features:
1874            self.logger.log(
1875                VERBOSE_LOG_LEVEL, "Selected protocol for %s: native", player.state.name
1876            )
1877            return player, None
1878
1879        # 4. Use the player's preferred default protocol domain, if it declares one and a
1880        # matching linked protocol is available (e.g. a LinkPlay shell prefers DLNA). This
1881        # never influences grouping; it only steers the default output for playback. "Auto"
1882        # is the entry default here, so it consistently resolves to this domain default.
1883        if default_domain := player.default_output_protocol_domain:
1884            for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
1885                if linked.protocol_domain != default_domain:
1886                    continue
1887                if (protocol_player := self.get_player(linked.output_protocol_id)) and (
1888                    protocol_player.available_for_playback
1889                ):
1890                    self.logger.log(
1891                        VERBOSE_LOG_LEVEL,
1892                        "Selected protocol for %s: %s (default domain %s)",
1893                        player.state.name,
1894                        protocol_player.state.name,
1895                        default_domain,
1896                    )
1897                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1898
1899        # 5. Fall back to best protocol by priority
1900        for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
1901            if protocol_player := self.get_player(linked.output_protocol_id):
1902                if protocol_player.available_for_playback:
1903                    self.logger.log(
1904                        VERBOSE_LOG_LEVEL,
1905                        "Selected protocol for %s: %s (priority-based)",
1906                        player.state.name,
1907                        protocol_player.state.name,
1908                    )
1909                    return protocol_player, player.get_linked_protocol(linked.output_protocol_id)
1910
1911        raise PlayerCommandFailed(f"Player {player.state.name} has no available output protocols")
1912
1913    def _get_control_target(
1914        self,
1915        player: Player,
1916        required_feature: PlayerFeature,
1917        require_active: bool = False,
1918    ) -> Player | None:
1919        """
1920        Get the best player(protocol) to send audio-path commands to.
1921
1922        Resolves commands that travel with the audio (enqueue, pause, announcements),
1923        so the output that renders the audio outranks the native player. Volume and
1924        mute are control-plane instead and resolve through
1925        :meth:`Player._get_protocol_player_for_feature`, which orders differently.
1926
1927        :param player: The player the command was issued on.
1928        :param required_feature: The feature the resolved target has to support.
1929        :param require_active: Only accept the output that is already rendering,
1930            instead of falling back to an idle one.
1931        """
1932        # If we have an active protocol, use that
1933        if (
1934            player.active_output_protocol
1935            and player.active_output_protocol != "native"
1936            and (protocol_player := self.mass.players.get_player(player.active_output_protocol))
1937            and required_feature in protocol_player.supported_features
1938        ):
1939            return protocol_player
1940
1941        # if the player natively supports the required feature, use that
1942        if (
1943            player.active_output_protocol == "native"
1944            and required_feature in player.supported_features
1945        ):
1946            return player
1947
1948        # If require_active is set, and no active protocol found, return None
1949        if require_active:
1950            return None
1951
1952        # if the player natively supports the required feature, use that
1953        if required_feature in player.supported_features:
1954            return player
1955
1956        # An output the user explicitly picked owns the audio, so a command that has to
1957        # start playback on an idle player follows it rather than the priority below.
1958        # The stored value survives a relink, so it only counts while it still names one
1959        # of this player's own outputs.
1960        preferred = self.mass.config.get_raw_player_config_value(
1961            player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
1962        )
1963        if preferred and preferred not in ("auto", "native"):
1964            for linked in player.linked_output_protocols:
1965                if linked.output_protocol_id != preferred:
1966                    continue
1967                if (
1968                    (preferred_player := self.mass.players.get_player(str(preferred)))
1969                    and preferred_player.available_for_playback
1970                    and required_feature in preferred_player.supported_features
1971                ):
1972                    return preferred_player
1973                break
1974
1975        # Otherwise, use the best available linked protocol, ordered by the same
1976        # priority that regular playback selection applies.
1977        for linked in sorted(player.linked_output_protocols, key=lambda x: x.priority):
1978            if (
1979                (protocol_player := self.mass.players.get_player(linked.output_protocol_id))
1980                and protocol_player.available_for_playback
1981                and required_feature in protocol_player.supported_features
1982            ):
1983                return protocol_player
1984
1985        return None
1986
1987    def _is_protocol_grouped(self, protocol_player: Player) -> bool:
1988        """
1989        Check if a protocol player is currently grouped/synced with other players.
1990
1991        Used to prefer protocols that are actively participating in a group,
1992        ensuring consistent playback across grouped players.
1993        """
1994        is_grouped = bool(
1995            protocol_player.state.synced_to
1996            or (
1997                protocol_player.state.group_members and len(protocol_player.state.group_members) > 1
1998            )
1999            or protocol_player.state.active_group
2000        )
2001        if is_grouped:
2002            self.logger.log(
2003                VERBOSE_LOG_LEVEL,
2004                "Protocol player %s is grouped",
2005                protocol_player.state.name,
2006            )
2007        return is_grouped
2008
2009    def _translate_members_to_remove_for_protocols(
2010        self,
2011        parent_player: Player,
2012        player_ids: list[str],
2013        parent_protocol_player: Player | None,
2014        parent_protocol_domain: str | None,
2015    ) -> tuple[list[str], list[str]]:
2016        """
2017        Translate member IDs to remove into protocol and native lists.
2018
2019        :param parent_player: The parent player to remove members from.
2020        :param player_ids: List of visible player IDs to remove.
2021        :param parent_protocol_player: The parent's protocol player if available.
2022        :param parent_protocol_domain: The parent's protocol domain if available.
2023        """
2024        self.logger.debug(
2025            "Translating members to remove for %s: player_ids=%s, parent_protocol_domain=%s",
2026            parent_player.state.name,
2027            player_ids,
2028            parent_protocol_domain,
2029        )
2030        protocol_members: list[str] = []
2031        native_members: list[str] = []
2032
2033        for child_player_id in player_ids:
2034            child_player = self.get_player(child_player_id)
2035            if not child_player:
2036                continue
2037
2038            # Check if this member is in the parent's group via protocol
2039            if parent_protocol_domain and parent_protocol_player:
2040                child_protocol = child_player.get_output_protocol_by_domain(parent_protocol_domain)
2041                if child_protocol and child_protocol.available:
2042                    # For native protocol players, use the child's player_id directly
2043                    child_protocol_id = (
2044                        child_player.player_id
2045                        if child_protocol.is_native
2046                        else child_protocol.output_protocol_id
2047                    )
2048                    if child_protocol_id in parent_protocol_player.group_members:
2049                        self.logger.debug(
2050                            "Translating removal: %s -> protocol %s",
2051                            child_player_id,
2052                            child_protocol_id,
2053                        )
2054                        protocol_members.append(child_protocol_id)
2055                        continue
2056
2057            # Check if child's protocol player is in parent's native group_members
2058            # This handles native protocol players (e.g., native AirPlay player like Apple TV)
2059            # where the parent itself contains protocol player IDs in its group_members
2060            translated = False
2061            for linked in child_player.linked_output_protocols:
2062                if linked.output_protocol_id in parent_player.group_members:
2063                    self.logger.debug(
2064                        "Translating removal (native parent): %s -> protocol %s",
2065                        child_player_id,
2066                        linked.output_protocol_id,
2067                    )
2068                    native_members.append(linked.output_protocol_id)
2069                    translated = True
2070                    break
2071
2072            if not translated:
2073                native_members.append(child_player_id)
2074
2075        return protocol_members, native_members
2076
2077    def _filter_protocol_members(self, member_ids: list[str], protocol_player: Player) -> list[str]:
2078        """Filter member IDs to only include players from the same protocol domain."""
2079        return [
2080            pid
2081            for pid in member_ids
2082            if (p := self.get_player(pid)) and p.provider.domain == protocol_player.provider.domain
2083        ]
2084
2085    def _filter_native_members(self, member_ids: list[str], parent_player: Player) -> list[str]:
2086        """Filter member IDs to only include players compatible with the parent."""
2087        return [
2088            pid
2089            for pid in member_ids
2090            if (p := self.get_player(pid))
2091            and (
2092                p.provider.instance_id == parent_player.provider.instance_id
2093                or pid in parent_player._attr_can_group_with
2094                or p.provider.instance_id in parent_player._attr_can_group_with
2095            )
2096        ]
2097
2098    def _try_child_preferred_protocol(
2099        self,
2100        child_player: Player,
2101        parent_player: Player,
2102    ) -> tuple[str | None, str | None]:
2103        """
2104        Try to use child's preferred output protocol for grouping.
2105
2106        Returns tuple of (child_protocol_id, protocol_domain) or (None, None).
2107        """
2108        child_preferred = self.mass.config.get_raw_player_config_value(
2109            child_player.player_id, CONF_PREFERRED_OUTPUT_PROTOCOL
2110        )
2111        if not child_preferred or child_preferred in {"auto", "native"}:
2112            return None, None
2113
2114        # Find child's preferred protocol, with its current availability
2115        child_protocol = None
2116        for output_protocol in child_player.output_protocols:
2117            if output_protocol.output_protocol_id == child_preferred:
2118                child_protocol = output_protocol
2119                break
2120
2121        if not child_protocol or not child_protocol.available:
2122            return None, None
2123
2124        # Check if parent supports this protocol (including native protocol)
2125        parent_protocol = parent_player.get_output_protocol_by_domain(
2126            child_protocol.protocol_domain
2127        )
2128        if not parent_protocol or not parent_protocol.available:
2129            return None, None
2130
2131        # Check if this protocol supports set_members
2132        protocol_player = parent_player.get_protocol_player(parent_protocol.output_protocol_id)
2133        if (
2134            not protocol_player
2135            or PlayerFeature.SET_MEMBERS not in protocol_player.state.supported_features
2136        ):
2137            return None, None
2138
2139        return child_protocol.output_protocol_id, child_protocol.protocol_domain
2140
2141    def _can_use_native_grouping(
2142        self,
2143        child_player: Player,
2144        parent_player: Player,
2145        parent_supports_native: bool,
2146    ) -> bool:
2147        """Check if child can be grouped with parent using native grouping."""
2148        if not parent_supports_native:
2149            return False
2150        return (
2151            parent_player.is_native_group_compatible(child_player)
2152            or child_player.player_id in parent_player._attr_can_group_with
2153            or child_player.provider.instance_id in parent_player._attr_can_group_with
2154        )
2155
2156    def _try_find_common_protocol(
2157        self, child_player: Player, parent_player: Player
2158    ) -> tuple[OutputProtocol | None, OutputProtocol | None]:
2159        """
2160        Find common protocol that supports set_members.
2161
2162        Returns tuple of (parent_protocol, child_protocol) or (None, None).
2163        """
2164        for parent_output_protocol in parent_player.output_protocols:
2165            if not parent_output_protocol.available:
2166                continue
2167            child_protocol = child_player.get_output_protocol_by_domain(
2168                parent_output_protocol.protocol_domain
2169            )
2170            if not child_protocol or not child_protocol.available:
2171                continue
2172            protocol_player = parent_player.get_protocol_player(
2173                parent_output_protocol.output_protocol_id
2174            )
2175            if protocol_player and PlayerFeature.SET_MEMBERS in protocol_player.supported_features:
2176                return parent_output_protocol, child_protocol
2177        return None, None
2178
2179    def _parent_has_live_native_session(self, parent_player: Player) -> bool:
2180        """
2181        Return True when the parent currently holds a live native playback session.
2182
2183        The active output protocol lingers for a few seconds after stop, so a non-idle
2184        playback state is required to distinguish a real session from a just-stopped one.
2185        """
2186        return parent_player.active_output_protocol == "native" and (
2187            parent_player.state.playback_state in (PlaybackState.PLAYING, PlaybackState.PAUSED)
2188        )
2189
2190    def _order_members_for_native_join(
2191        self,
2192        player_ids: list[str],
2193        parent_player: Player,
2194        parent_supports_native_grouping: bool,
2195    ) -> list[str]:
2196        """
2197        Order members so a live native session can be joined without splitting the group.
2198
2199        When the parent already holds a live native session, children that cannot group
2200        natively are evaluated first: they may force a shared protocol for the whole group,
2201        and processing them before the native-capable children lets those join that same
2202        protocol instead of being stranded in a separate native sub-group. The order is left
2203        untouched when the parent is not playing natively, so fresh-group selection is unchanged.
2204
2205        :param player_ids: The member IDs to be added, in their original order.
2206        :param parent_player: The parent player being joined.
2207        :param parent_supports_native_grouping: Whether the parent can group natively.
2208        """
2209        if not self._parent_has_live_native_session(parent_player):
2210            return player_ids
2211        return sorted(
2212            player_ids,
2213            key=lambda pid: bool(
2214                (child := self.get_player(pid))
2215                and self._can_use_native_grouping(
2216                    child, parent_player, parent_supports_native_grouping
2217                )
2218            ),
2219        )
2220
2221    def _try_join_active_native_session(
2222        self,
2223        child_player: Player,
2224        parent_player: Player,
2225        parent_protocol_domain: str | None,
2226        parent_supports_native_grouping: bool,
2227        native_members: list[str],
2228    ) -> bool:
2229        """
2230        Add the child to native_members if it can join the parent's active native session.
2231
2232        A child's preferred output protocol must only steer protocol selection when the child
2233        initiates its own playback; when it joins a parent that is already playing natively it
2234        should adopt native grouping if compatible, rather than forcing the whole group onto
2235        the child's preferred protocol. Skipped once a protocol has been selected for the group,
2236        so mixed batches stay cohesive on a single protocol.
2237
2238        :param child_player: The player being added to the group.
2239        :param parent_player: The parent player being joined.
2240        :param parent_protocol_domain: The protocol domain already selected for the group, if any.
2241        :param parent_supports_native_grouping: Whether the parent can group natively.
2242        :param native_members: The native members list to append to when the child joins.
2243        """
2244        if not (
2245            self._parent_has_live_native_session(parent_player)
2246            and not parent_protocol_domain
2247            and self._can_use_native_grouping(
2248                child_player, parent_player, parent_supports_native_grouping
2249            )
2250        ):
2251            return False
2252        native_members.append(child_player.player_id)
2253        self.logger.log(
2254            VERBOSE_LOG_LEVEL,
2255            "Joining parent's active native session for %s",
2256            child_player.state.name,
2257        )
2258        return True
2259
2260    def _translate_native_members_to_protocol(
2261        self, parent_player: Player, protocol_domain: str, member_ids: list[str]
2262    ) -> list[str]:
2263        """
2264        Translate natively grouped members onto the protocol domain the parent plays through.
2265
2266        Members that do not have that protocol cannot follow the parent at all and are
2267        dropped with a warning instead.
2268
2269        :param parent_player: The parent player the members are grouped with.
2270        :param protocol_domain: The protocol domain selected for the group.
2271        :param member_ids: The member IDs that were selected for native grouping.
2272        """
2273        translated: list[str] = []
2274        for member_id in member_ids:
2275            member_player = self.get_player(member_id)
2276            if not member_player:
2277                continue
2278            # a native group's members may be listed by their protocol player id
2279            if member_player.protocol_parent_id:
2280                member_player = self.get_player(member_player.protocol_parent_id) or member_player
2281            member_protocol = member_player.get_output_protocol_by_domain(protocol_domain)
2282            if not member_protocol or not member_protocol.available:
2283                self.logger.warning(
2284                    "Cannot group %s with %s: the group plays through the %s protocol, "
2285                    "which %s does not support",
2286                    member_player.state.name,
2287                    parent_player.state.name,
2288                    protocol_domain,
2289                    member_player.state.name,
2290                )
2291                continue
2292            # For native protocol players, use the member's player_id directly
2293            translated.append(
2294                member_player.player_id
2295                if member_protocol.is_native
2296                else member_protocol.output_protocol_id
2297            )
2298            self.logger.log(
2299                VERBOSE_LOG_LEVEL,
2300                "Moving %s from native grouping to the %s protocol",
2301                member_player.state.name,
2302                protocol_domain,
2303            )
2304        return translated
2305
2306    def _move_native_members_to_group_protocol(
2307        self,
2308        parent_player: Player,
2309        parent_protocol_player: Player | None,
2310        parent_protocol_domain: str | None,
2311        protocol_members: list[str],
2312        native_members: list[str],
2313    ) -> None:
2314        """
2315        Move the members selected for native grouping onto the protocol the group ended up on.
2316
2317        Does nothing unless the group ends up on one of the parent's protocols while the
2318        parent's native grouping needs the parent's own stream: only then do those members
2319        have no session left to attach to.
2320
2321        :param parent_player: The parent player being joined.
2322        :param parent_protocol_player: The protocol player selected for the group, if any.
2323        :param parent_protocol_domain: The protocol domain selected for the group, if any.
2324        :param protocol_members: The protocol member list the translated IDs are added to.
2325        :param native_members: The native member IDs, emptied when they are moved over.
2326        """
2327        if not (
2328            native_members
2329            and parent_protocol_domain
2330            and parent_protocol_player
2331            and parent_protocol_player.player_id != parent_player.player_id
2332            and parent_player.native_grouping_requires_own_stream
2333        ):
2334            return
2335        protocol_members.extend(
2336            self._translate_native_members_to_protocol(
2337                parent_player, parent_protocol_domain, native_members
2338            )
2339        )
2340        native_members.clear()
2341
2342    def _migrate_stranded_native_members(
2343        self,
2344        parent_player: Player,
2345        parent_protocol_player: Player,
2346        protocol_members: list[str],
2347    ) -> list[str]:
2348        """
2349        Move the native members that a switch to the given protocol strands onto that protocol.
2350
2351        Returns the member IDs that are still attached to the parent's own stream, so the
2352        caller can release them from it. Empty unless the parent renders that stream itself
2353        while its native grouping attaches the members to exactly that stream: only then are
2354        they left without anything to play.
2355
2356        :param parent_player: The parent player that is about to switch protocol.
2357        :param parent_protocol_player: The protocol player the parent will render through.
2358        :param protocol_members: The protocol member list the translated IDs are added to.
2359        """
2360        if parent_protocol_player.player_id == parent_player.player_id:
2361            return []
2362        if not parent_player.native_grouping_requires_own_stream:
2363            return []
2364        if parent_player.active_output_protocol not in (None, "native"):
2365            return []
2366        if parent_player.state.playback_state not in (PlaybackState.PLAYING, PlaybackState.PAUSED):
2367            return []
2368        stranded = [
2369            member_id
2370            for member_id in parent_player.group_members
2371            if member_id != parent_player.player_id
2372        ]
2373        for protocol_id in self._translate_native_members_to_protocol(
2374            parent_player, parent_protocol_player.provider.domain, stranded
2375        ):
2376            if protocol_id not in protocol_members:
2377                protocol_members.append(protocol_id)
2378        return stranded
2379
2380    async def _stop_native_session(
2381        self,
2382        parent_player: Player,
2383        parent_protocol_player: Player,
2384        stranded_native_members: list[str],
2385    ) -> None:
2386        """
2387        Release the given members from the parent's own stream and stop it.
2388
2389        :param parent_player: The parent player whose native session is handed over.
2390        :param parent_protocol_player: The protocol player taking the output over.
2391        :param stranded_native_members: The members to release, already migrated.
2392        """
2393        self.logger.debug(
2394            "Stopping the native session of %s before switching to %s, migrated members: %s",
2395            parent_player.state.name,
2396            parent_protocol_player.state.name,
2397            stranded_native_members,
2398        )
2399        # The members already joined the protocol group, so the native session only has to
2400        # release them and stop. Releasing them first also clears the native group, which
2401        # keeps a later native playback command from resurrecting it. Both calls take the
2402        # provider's own lock, so they must run one after the other.
2403        await parent_player.set_members(player_ids_to_remove=stranded_native_members)
2404        await parent_player.stop()
2405
2406    def _translate_members_for_protocols(
2407        self,
2408        parent_player: Player,
2409        player_ids: list[str],
2410        parent_protocol_player: Player | None,
2411        parent_protocol_domain: str | None,
2412    ) -> tuple[list[str], list[str], Player | None, str | None]:
2413        """
2414        Translate member IDs to protocol or native IDs.
2415
2416        The grouping method is picked per member, see _select_grouping_for_member.
2417
2418        Returns tuple of (protocol_members, native_members, protocol_player, protocol_domain).
2419        """
2420        protocol_members: list[str] = []
2421        native_members: list[str] = []
2422        parent_supports_native_grouping = (
2423            PlayerFeature.SET_MEMBERS in parent_player.supported_features
2424        )
2425        player_ids = self._order_members_for_native_join(
2426            player_ids, parent_player, parent_supports_native_grouping
2427        )
2428
2429        self.logger.log(
2430            VERBOSE_LOG_LEVEL,
2431            "Translating members for %s: parent_supports_native=%s, parent_protocol=%s (%s)",
2432            parent_player.state.name,
2433            parent_supports_native_grouping,
2434            parent_protocol_player.state.name if parent_protocol_player else "none",
2435            parent_protocol_domain or "none",
2436        )
2437
2438        for child_player_id in player_ids:
2439            child_player = self.get_player(child_player_id)
2440            if not child_player:
2441                continue
2442
2443            self.logger.log(
2444                VERBOSE_LOG_LEVEL,
2445                "Processing child %s (type=%s, protocols=%s)",
2446                child_player.state.name,
2447                child_player.state.type,
2448                [p.protocol_domain for p in child_player.output_protocols],
2449            )
2450
2451            parent_protocol_player, parent_protocol_domain = self._select_grouping_for_member(
2452                child_player,
2453                parent_player,
2454                parent_protocol_player,
2455                parent_protocol_domain,
2456                parent_supports_native_grouping,
2457                protocol_members,
2458                native_members,
2459            )
2460
2461        # Post-pass: the protocol selected for the group is only known once every child has
2462        # been processed, so the members picked for native grouping are corrected here.
2463        self._move_native_members_to_group_protocol(
2464            parent_player,
2465            parent_protocol_player,
2466            parent_protocol_domain,
2467            protocol_members,
2468            native_members,
2469        )
2470
2471        return protocol_members, native_members, parent_protocol_player, parent_protocol_domain
2472
2473    def _select_grouping_for_member(
2474        self,
2475        child_player: Player,
2476        parent_player: Player,
2477        parent_protocol_player: Player | None,
2478        parent_protocol_domain: str | None,
2479        parent_supports_native_grouping: bool,
2480        protocol_members: list[str],
2481        native_members: list[str],
2482    ) -> tuple[Player | None, str | None]:
2483        """
2484        Pick the grouping method for a single member and add it to the matching member list.
2485
2486        Selection priority when grouping:
2487        0. If the parent is already playing natively and the child can be grouped
2488           natively, join that native session (a child joining an existing group must
2489           not force the whole group onto its own preferred output protocol)
2490        1. Try child's preferred output protocol (from player settings)
2491        2. Try parent's active output protocol (if any and child supports it)
2492        3. Try native grouping (if parent and child are compatible)
2493        4. Search for common protocol that supports set_members
2494        5. Log warning if no option works
2495
2496        Returns the protocol player/domain the group is on, which the picked method may have
2497        changed.
2498
2499        :param child_player: The player being added to the group.
2500        :param parent_player: The parent player being joined.
2501        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2502        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2503        :param parent_supports_native_grouping: Whether the parent can group natively.
2504        :param protocol_members: The protocol member list to append to.
2505        :param native_members: The native member list to append to.
2506        """
2507        # Priority 0: The parent is already playing natively and the child can join
2508        # that native session directly - adopt it before considering the child's own
2509        # preferred output protocol.
2510        if self._try_join_active_native_session(
2511            child_player,
2512            parent_player,
2513            parent_protocol_domain,
2514            parent_supports_native_grouping,
2515            native_members,
2516        ):
2517            return parent_protocol_player, parent_protocol_domain
2518
2519        # Priority 0.5: a player that runs its own multiroom (e.g. a LinkPlay control shell)
2520        # keeps grouping on its native path rather than routing it through a linked protocol
2521        # that is merely its preferred playback output. Native compatibility still decides
2522        # whether this is possible, so an incompatible/cross-backend pair falls through.
2523        if child_player.prefer_native_grouping and self._can_use_native_grouping(
2524            child_player, parent_player, parent_supports_native_grouping
2525        ):
2526            native_members.append(child_player.player_id)
2527            self.logger.log(
2528                VERBOSE_LOG_LEVEL,
2529                "Using native grouping (preferred) for %s",
2530                child_player.state.name,
2531            )
2532            return parent_protocol_player, parent_protocol_domain
2533
2534        # Priority 1: the child's preferred output protocol
2535        grouped, parent_protocol_player, parent_protocol_domain = (
2536            self._try_group_via_preferred_protocol(
2537                child_player,
2538                parent_player,
2539                parent_protocol_player,
2540                parent_protocol_domain,
2541                protocol_members,
2542            )
2543        )
2544        if grouped:
2545            return parent_protocol_player, parent_protocol_domain
2546
2547        # Priority 2: the protocol the group is already on
2548        grouped, parent_protocol_player, parent_protocol_domain = (
2549            self._try_group_via_active_protocol(
2550                child_player,
2551                parent_protocol_player,
2552                parent_protocol_domain,
2553                protocol_members,
2554            )
2555        )
2556        if grouped:
2557            return parent_protocol_player, parent_protocol_domain
2558
2559        # Priority 3: native grouping
2560        if self._can_use_native_grouping(
2561            child_player, parent_player, parent_supports_native_grouping
2562        ):
2563            native_members.append(child_player.player_id)
2564            self.logger.log(
2565                VERBOSE_LOG_LEVEL,
2566                "Using native grouping for %s",
2567                child_player.state.name,
2568            )
2569            return parent_protocol_player, parent_protocol_domain
2570
2571        # Priority 4: a protocol both players share that supports set_members
2572        grouped, parent_protocol_player, parent_protocol_domain = (
2573            self._try_group_via_common_protocol(
2574                child_player,
2575                parent_player,
2576                parent_protocol_player,
2577                parent_protocol_domain,
2578                protocol_members,
2579            )
2580        )
2581        if grouped:
2582            return parent_protocol_player, parent_protocol_domain
2583
2584        # Priority 5: no option worked
2585        self.logger.warning(
2586            "Cannot group %s with %s: no compatible grouping method found "
2587            "(tried: child preferred protocol, parent active protocol, "
2588            "native grouping, common protocols)",
2589            child_player.state.name,
2590            parent_player.state.name,
2591        )
2592        return parent_protocol_player, parent_protocol_domain
2593
2594    def _try_group_via_preferred_protocol(
2595        self,
2596        child_player: Player,
2597        parent_player: Player,
2598        parent_protocol_player: Player | None,
2599        parent_protocol_domain: str | None,
2600        protocol_members: list[str],
2601    ) -> tuple[bool, Player | None, str | None]:
2602        """
2603        Try to group the child through the output protocol it prefers in its player settings.
2604
2605        Only used when the group is not on a protocol yet or is already on that same protocol.
2606        Returns whether the child was grouped, together with the protocol player/domain the
2607        group is on: the child's preferred protocol may become the group's protocol.
2608
2609        :param child_player: The player being added to the group.
2610        :param parent_player: The parent player being joined.
2611        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2612        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2613        :param protocol_members: The protocol member list to append to.
2614        """
2615        child_protocol_id, protocol_domain = self._try_child_preferred_protocol(
2616            child_player, parent_player
2617        )
2618        if not (
2619            child_protocol_id
2620            and protocol_domain
2621            and (not parent_protocol_domain or protocol_domain == parent_protocol_domain)
2622        ):
2623            return False, parent_protocol_player, parent_protocol_domain
2624
2625        if not parent_protocol_player or parent_protocol_domain != protocol_domain:
2626            parent_protocol = parent_player.get_output_protocol_by_domain(protocol_domain)
2627            if parent_protocol:
2628                parent_protocol_player = parent_player.get_protocol_player(
2629                    parent_protocol.output_protocol_id
2630                )
2631                parent_protocol_domain = protocol_domain
2632        protocol_members.append(child_protocol_id)
2633        self.logger.log(
2634            VERBOSE_LOG_LEVEL,
2635            "Using child's preferred protocol %s for %s",
2636            protocol_domain,
2637            child_player.state.name,
2638        )
2639        return True, parent_protocol_player, parent_protocol_domain
2640
2641    def _try_group_via_active_protocol(
2642        self,
2643        child_player: Player,
2644        parent_protocol_player: Player | None,
2645        parent_protocol_domain: str | None,
2646        protocol_members: list[str],
2647    ) -> tuple[bool, Player | None, str | None]:
2648        """
2649        Try to group the child through the protocol the group is already on.
2650
2651        Returns whether the child was grouped, together with the protocol player/domain the
2652        group is on: the selection is dropped when that protocol cannot group members itself,
2653        so a later grouping method can select another one.
2654
2655        :param child_player: The player being added to the group.
2656        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2657        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2658        :param protocol_members: The protocol member list to append to.
2659        """
2660        if not parent_protocol_domain or not parent_protocol_player:
2661            return False, parent_protocol_player, parent_protocol_domain
2662
2663        if PlayerFeature.SET_MEMBERS not in parent_protocol_player.state.supported_features:
2664            self.logger.log(
2665                VERBOSE_LOG_LEVEL,
2666                "Parent's active protocol %s does not support SET_MEMBERS, "
2667                "will search for alternative",
2668                parent_protocol_domain,
2669            )
2670            # Drop the selection so a later grouping method can select a new protocol
2671            return False, None, None
2672
2673        child_protocol = child_player.get_output_protocol_by_domain(parent_protocol_domain)
2674        if not child_protocol or not child_protocol.available:
2675            return False, parent_protocol_player, parent_protocol_domain
2676
2677        # For native protocol players, use the child's player_id directly
2678        # (e.g., a native sendspin web player IS the protocol player)
2679        child_protocol_id = (
2680            child_player.player_id
2681            if child_protocol.is_native
2682            else child_protocol.output_protocol_id
2683        )
2684        protocol_members.append(child_protocol_id)
2685        self.logger.log(
2686            VERBOSE_LOG_LEVEL,
2687            "Using parent's active protocol %s for %s",
2688            parent_protocol_domain,
2689            child_player.state.name,
2690        )
2691        return True, parent_protocol_player, parent_protocol_domain
2692
2693    def _try_group_via_common_protocol(
2694        self,
2695        child_player: Player,
2696        parent_player: Player,
2697        parent_protocol_player: Player | None,
2698        parent_protocol_domain: str | None,
2699        protocol_members: list[str],
2700    ) -> tuple[bool, Player | None, str | None]:
2701        """
2702        Try to group the child through a protocol both players share.
2703
2704        Returns whether the child was grouped, together with the protocol player/domain the
2705        group is on: the shared protocol may become the group's protocol.
2706
2707        :param child_player: The player being added to the group.
2708        :param parent_player: The parent player being joined.
2709        :param parent_protocol_player: The protocol player selected for the group so far, if any.
2710        :param parent_protocol_domain: The protocol domain selected for the group so far, if any.
2711        :param protocol_members: The protocol member list to append to.
2712        """
2713        parent_protocol, child_protocol = self._try_find_common_protocol(
2714            child_player, parent_player
2715        )
2716        if not parent_protocol or not child_protocol:
2717            return False, parent_protocol_player, parent_protocol_domain
2718
2719        if not parent_protocol_player or parent_protocol_domain != parent_protocol.protocol_domain:
2720            parent_protocol_player = parent_player.get_protocol_player(
2721                parent_protocol.output_protocol_id
2722            )
2723            if parent_protocol_player:
2724                parent_protocol_domain = parent_protocol_player.provider.domain
2725        # For native protocol players, use the child's player_id directly
2726        child_protocol_id = (
2727            child_player.player_id
2728            if child_protocol.is_native
2729            else child_protocol.output_protocol_id
2730        )
2731        protocol_members.append(child_protocol_id)
2732        self.logger.log(
2733            VERBOSE_LOG_LEVEL,
2734            "Selected common protocol %s for grouping %s with %s",
2735            parent_protocol.protocol_domain,
2736            child_player.state.name,
2737            parent_player.state.name,
2738        )
2739        return True, parent_protocol_player, parent_protocol_domain
2740
2741    async def _forward_protocol_set_members(
2742        self,
2743        parent_player: Player,
2744        parent_protocol_player: Player,
2745        protocol_members_to_add: list[str],
2746        protocol_members_to_remove: list[str],
2747    ) -> None:
2748        """
2749        Forward protocol members to protocol player's set_members and manage active output protocol.
2750
2751        :param parent_player: The parent player (native/universal).
2752        :param parent_protocol_player: The protocol player to forward commands to.
2753        :param protocol_members_to_add: Protocol player IDs to add.
2754        :param protocol_members_to_remove: Protocol player IDs to remove.
2755        """
2756        filtered_protocol_add = self._filter_protocol_members(
2757            protocol_members_to_add, parent_protocol_player
2758        )
2759        filtered_protocol_remove = self._filter_protocol_members(
2760            protocol_members_to_remove, parent_protocol_player
2761        )
2762        self.logger.debug(
2763            "Protocol grouping on %s: filtered_add=%s, filtered_remove=%s",
2764            parent_protocol_player.state.name,
2765            filtered_protocol_add,
2766            filtered_protocol_remove,
2767        )
2768
2769        if not filtered_protocol_add and not filtered_protocol_remove:
2770            return
2771
2772        # Safety check: verify protocol player supports SET_MEMBERS
2773        if PlayerFeature.SET_MEMBERS not in parent_protocol_player.state.supported_features:
2774            self.logger.error(
2775                "Protocol player %s does not support SET_MEMBERS, cannot perform grouping. "
2776                "This should have been caught earlier in the flow.",
2777                parent_protocol_player.state.name,
2778            )
2779            return
2780
2781        # Members that ride the parent's own stream are stranded by the protocol switch below,
2782        # so they join the protocol group in this very same call and their native session is
2783        # torn down afterwards.
2784        stranded_native_members = (
2785            self._migrate_stranded_native_members(
2786                parent_player, parent_protocol_player, filtered_protocol_add
2787            )
2788            if filtered_protocol_add
2789            else []
2790        )
2791
2792        # This runs before set_members because a member's own stream starts inside that call
2793        # and the provider resolves the member's volume control as it starts: unless its parent
2794        # already points at this protocol, that resolution picks a sibling interface of the same
2795        # device (e.g. its cast side) over the one carrying the audio.
2796        self._activate_protocol_on_added_children(filtered_protocol_add)
2797
2798        self.logger.debug(
2799            "Calling set_members on protocol player %s with add=%s, remove=%s",
2800            parent_protocol_player.state.name,
2801            filtered_protocol_add,
2802            filtered_protocol_remove,
2803        )
2804        await parent_protocol_player.set_members(
2805            player_ids_to_add=filtered_protocol_add or None,
2806            player_ids_to_remove=filtered_protocol_remove or None,
2807        )
2808
2809        if filtered_protocol_add:
2810            await self._activate_group_output_protocol(
2811                parent_player, parent_protocol_player, stranded_native_members
2812            )
2813
2814        self.logger.debug(
2815            "After set_members, protocol player %s state: group_members=%s, synced_to=%s",
2816            parent_protocol_player.state.name,
2817            parent_protocol_player.group_members,
2818            parent_protocol_player.synced_to,
2819        )
2820
2821    def _activate_protocol_on_added_children(self, protocol_member_ids: list[str]) -> None:
2822        """
2823        Point the parent of each given protocol member at the protocol carrying the group audio.
2824
2825        :param protocol_member_ids: The protocol player IDs joining the group.
2826        """
2827        for child_protocol_id in protocol_member_ids:
2828            if not (child_protocol := self.get_player(child_protocol_id)):
2829                continue
2830            if not child_protocol.protocol_parent_id:
2831                continue
2832            if not (child_player := self.get_player(child_protocol.protocol_parent_id)):
2833                continue
2834            if child_player.active_output_protocol == child_protocol_id:
2835                continue
2836            self.logger.debug(
2837                "Setting active output protocol on child %s to %s",
2838                child_player.state.name,
2839                child_protocol_id,
2840            )
2841            child_player.set_active_output_protocol(child_protocol_id)
2842
2843    async def _activate_group_output_protocol(
2844        self,
2845        parent_player: Player,
2846        parent_protocol_player: Player,
2847        stranded_native_members: list[str],
2848    ) -> None:
2849        """
2850        Mark the given protocol as the parent's output and hand the playback over to it.
2851
2852        The handover only runs when the parent is actually switching protocol while it is
2853        rendering; playback is resumed only for a parent that was playing, so adding a member
2854        never starts playback on its own.
2855
2856        :param parent_player: The parent player that just gained protocol members.
2857        :param parent_protocol_player: The protocol player the members joined.
2858        :param stranded_native_members: The members left without a stream by the switch.
2859        """
2860        previous_protocol = parent_player.active_output_protocol
2861        was_playing = parent_player.state.playback_state == PlaybackState.PLAYING
2862        # A paused player still holds its output, so the handover has to run for it too.
2863        was_rendering = was_playing or parent_player.state.playback_state == PlaybackState.PAUSED
2864
2865        # Native protocol: parent_protocol_player is the same as parent_player
2866        is_native_protocol = parent_protocol_player.player_id == parent_player.player_id
2867        already_using_native = previous_protocol in (None, "native")
2868        already_using_this_protocol = previous_protocol == parent_protocol_player.player_id
2869        switching_protocols = not (
2870            (is_native_protocol and already_using_native) or already_using_this_protocol
2871        )
2872
2873        self.logger.debug(
2874            "Protocol grouping: is_native=%s, already_native=%s, already_this=%s, "
2875            "switching=%s, was_rendering=%s",
2876            is_native_protocol,
2877            already_using_native,
2878            already_using_this_protocol,
2879            switching_protocols,
2880            was_rendering,
2881        )
2882
2883        if not (is_native_protocol and already_using_native):
2884            parent_player.set_active_output_protocol(parent_protocol_player.player_id)
2885
2886        if not (was_rendering and switching_protocols):
2887            return
2888
2889        self.logger.info(
2890            "Handing the output of %s over to the %s protocol%s",
2891            parent_player.state.name,
2892            parent_protocol_player.provider.domain,
2893            " and resuming playback" if was_playing else "",
2894        )
2895        if stranded_native_members:
2896            await self._stop_native_session(
2897                parent_player, parent_protocol_player, stranded_native_members
2898            )
2899        old_parent_members = await self._stop_previous_protocol(
2900            parent_player, parent_protocol_player, previous_protocol
2901        )
2902        if was_playing:
2903            await self.mass.players.cmd_resume(parent_player.player_id)
2904        if old_parent_members:
2905            self.logger.debug(
2906                "Re-adding migrated members %s to %s on new protocol",
2907                old_parent_members,
2908                parent_player.state.name,
2909            )
2910            # Use internal handler because we are already inside a
2911            # _handle_set_members call chain that holds the play lock.
2912            await self.mass.players._handle_set_members(
2913                parent_player,
2914                player_ids_to_add=old_parent_members,
2915            )
2916
2917    async def _stop_previous_protocol(
2918        self,
2919        parent_player: Player,
2920        parent_protocol_player: Player,
2921        previous_protocol: str | None,
2922    ) -> list[str]:
2923        """
2924        Stop the protocol player the parent was rendering through and return its members.
2925
2926        The returned IDs are parent player IDs, so the caller can re-add them to the group
2927        once the new protocol carries the audio. Empty if there is nothing to hand over.
2928
2929        :param parent_player: The parent player that is switching protocol.
2930        :param parent_protocol_player: The protocol player taking the output over.
2931        :param previous_protocol: The parent's previous active output protocol, if any.
2932        """
2933        if previous_protocol in (None, "native"):
2934            return []
2935        if not (old_protocol_player := self.get_player(previous_protocol)):
2936            return []
2937        if old_protocol_player.player_id == parent_protocol_player.player_id:
2938            return []
2939        # Translate the old protocol's child members back to parent player IDs
2940        old_parent_members: list[str] = []
2941        for member_id in old_protocol_player.group_members:
2942            if member_id == old_protocol_player.player_id:
2943                continue
2944            if not (member_player := self.get_player(member_id)):
2945                continue
2946            parent_id = member_player.protocol_parent_id or member_id
2947            if parent_id != parent_player.player_id:
2948                old_parent_members.append(parent_id)
2949        self.logger.debug(
2950            "Stopping old protocol player %s before switching to %s, migrating members: %s",
2951            old_protocol_player.state.name,
2952            parent_protocol_player.state.name,
2953            old_parent_members,
2954        )
2955        # Use internal handler to stop the specific protocol player,
2956        # bypassing group/sync redirect and queue redirect logic.
2957        await self.mass.players._handle_cmd_stop(old_protocol_player.player_id)
2958        return old_parent_members
2959