acdream/src/AcDream.Runtime/Session/LiveSessionEventRouter.cs

using AcDream.Core.Chat;
using AcDream.Core.Combat;
using AcDream.Core.Items;
using AcDream.Core.Net;
using AcDream.Core.Net.Messages;
using AcDream.Core.Physics;
using AcDream.Core.Player;
using AcDream.Core.Properties;
using AcDream.Core.Social;
using AcDream.Core.Spells;
using AcDream.Runtime.Gameplay;

namespace AcDream.Runtime.Session;

public sealed record LiveEntitySessionSink(
    Action<WorldSession.EntitySpawn> Spawned,
    Action<DeleteObject.Parsed> Deleted,
    Action<PickupEvent.Parsed> PickedUp,
    Action<WorldSession.EntityMotionUpdate> MotionUpdated,
    Action<WorldSession.EntityPositionUpdate> PositionUpdated,
    Action<VectorUpdate.Parsed> VectorUpdated,
    Action<SetState.Parsed> StateUpdated,
    Action<ParentEvent.Parsed> ParentUpdated,
    Action<uint> TeleportStarted,
    Action<ObjDescEvent.Parsed> AppearanceUpdated,
    Action<PlayPhysicsScript> PlayPhysicsScript,
    Action<PlayPhysicsScriptType> PlayPhysicsScriptType,
    Action<SoundEvent> SoundEvent);

public sealed record LiveEnvironmentSessionSink(
    Action<uint> EnvironChanged,
    Action<double> ServerTimeUpdated);

public sealed record LiveInventorySessionBindings(
    ClientObjectTable Objects,
    Func<uint> PlayerGuid,
    Action<IReadOnlyList<ShortcutEntry>>? OnShortcuts,
    Action<uint>? OnUseDone,
    ItemManaState? ItemMana,
    ExternalContainerState? ExternalContainers,
    Action<AppraiseInfoParser.Parsed>? OnAppraisal = null,
    // Slice 5.3: the vendor browse session owner. Trailing/optional so every
    // existing positional caller (Headless) compiles unchanged.
    VendorState? Vendor = null);

public sealed record LiveCharacterSessionBindings(
    CombatState Combat,
    RuntimeCharacterState Character,
    Func<uint, IReadOnlyDictionary<uint, uint>, uint>? ResolveSkillFormulaBonus,
    Action<int, int>? OnSkillsUpdated,
    Action<GameEvents.CharacterConfirmationRequest>? OnConfirmationRequest,
    Action<GameEvents.CharacterConfirmationDone>? OnConfirmationDone,
    Func<double>? ClientTime,
    // Campaign P Slice P1 (2026-07-30): fires after MovementSkills' burden,
    // stamina, OR (vitae/enchantment-adjusted) skill values change mid-
    // session — the reactive re-apply-to-the-live-controller seam, mirroring
    // OnSkillsUpdated's existing shape. Optional/nullable so every existing
    // caller (including Headless's OnSkillsUpdated: null pattern) compiles
    // unchanged.
    Action? OnMovementStatsUpdated = null);

public sealed record LiveSocialSessionBindings(
    ChatLog Chat,
    TurbineChatState TurbineChat,
    FriendsState? Friends,
    SquelchState? Squelch);

/// <summary>
/// Owns every inbound subscription for one exact live session. Domain state
/// remains in the supplied sinks; this class owns only routing and teardown.
/// </summary>
public sealed class LiveSessionEventRouter : ILiveSessionEventRouting
{
    private readonly LiveSessionSubscriptionSet _subscriptions = new();
    private readonly Action<int>? _constructionCheckpoint;
    private readonly WorldSession _session;
    private readonly LiveEntitySessionSink _entities;
    private readonly LiveEnvironmentSessionSink _environment;
    private readonly LiveInventorySessionBindings _inventory;
    private readonly LiveCharacterSessionBindings _character;
    private readonly LiveSocialSessionBindings _social;
    private int _constructionStep;
    private int _accepting;
    private int _lifecycleState; // 0 created, 1 attaching, 2 attached, 3 disposed

    public LiveSessionEventRouter(
        WorldSession session,
        LiveEntitySessionSink entities,
        LiveEnvironmentSessionSink environment,
        LiveInventorySessionBindings inventory,
        LiveCharacterSessionBindings character,
        LiveSocialSessionBindings social,
        Action<int>? constructionCheckpoint = null)
    {
        ArgumentNullException.ThrowIfNull(session);
        Validate(entities, environment, inventory, character, social);
        _session = session;
        _entities = entities;
        _environment = environment;
        _inventory = inventory;
        _character = character;
        _social = social;
        _constructionCheckpoint = constructionCheckpoint;
    }

    public void Attach()
    {
        if (Interlocked.CompareExchange(ref _lifecycleState, 1, 0) != 0)
            throw new InvalidOperationException(
                "Live-session event routing can only attach once.");

        Interlocked.Exchange(ref _accepting, 1);
        WorldSession session = _session;
        LiveEntitySessionSink entities = _entities;
        LiveEnvironmentSessionSink environment = _environment;
        LiveInventorySessionBindings inventory = _inventory;
        LiveCharacterSessionBindings character = _character;
        LiveSocialSessionBindings social = _social;

        try
        {
            // Preserve the shipped pre-Connect registration order. Property
            // state is installed before lifecycle packets can be dispatched.
            _subscriptions.Add(ObjectTableWiring.Wire(
                session,
                inventory.Objects,
                inventory.PlayerGuid,
                character.Character.LocalPlayer,
                IsAccepting));
            ConstructionCheckpoint();
            _subscriptions.Add(CombatStateWiring.Wire(
                session,
                character.Combat,
                IsAccepting));
            ConstructionCheckpoint();

            Subscribe(h => session.EntitySpawned += h, h => session.EntitySpawned -= h, entities.Spawned);
            Subscribe(h => session.EntityDeleted += h, h => session.EntityDeleted -= h, entities.Deleted);
            Subscribe(h => session.EntityPickedUp += h, h => session.EntityPickedUp -= h, entities.PickedUp);
            Subscribe(h => session.MotionUpdated += h, h => session.MotionUpdated -= h, entities.MotionUpdated);
            Subscribe(h => session.PositionUpdated += h, h => session.PositionUpdated -= h, entities.PositionUpdated);
            Subscribe(h => session.VectorUpdated += h, h => session.VectorUpdated -= h, entities.VectorUpdated);
            Subscribe(h => session.StateUpdated += h, h => session.StateUpdated -= h, entities.StateUpdated);
            Subscribe(h => session.ParentUpdated += h, h => session.ParentUpdated -= h, entities.ParentUpdated);
            Subscribe(h => session.TeleportStarted += h, h => session.TeleportStarted -= h, entities.TeleportStarted);
            Subscribe(h => session.AppearanceUpdated += h, h => session.AppearanceUpdated -= h, entities.AppearanceUpdated);
            Subscribe(
                h => session.PlayPhysicsScriptReceived += h,
                h => session.PlayPhysicsScriptReceived -= h,
                entities.PlayPhysicsScript);
            Subscribe(
                h => session.PlayPhysicsScriptTypeReceived += h,
                h => session.PlayPhysicsScriptTypeReceived -= h,
                entities.PlayPhysicsScriptType);
            Subscribe(
                h => session.SoundEventReceived += h,
                h => session.SoundEventReceived -= h,
                entities.SoundEvent);

            Subscribe(h => session.EnvironChanged += h, h => session.EnvironChanged -= h, environment.EnvironChanged);
            Subscribe(h => session.ServerTimeUpdated += h, h => session.ServerTimeUpdated -= h, environment.ServerTimeUpdated);

            _subscriptions.Add(GameEventWiring.WireAll(
                session.GameEvents,
                inventory.Objects,
                character.Combat,
                character.Character.Spellbook,
                social.Chat,
                character.Character.LocalPlayer,
                social.TurbineChat,
                onSkillsUpdated: (runSkill, jumpSkill) =>
                {
                    // Campaign P Slice P1 (2026-07-30): route the PD/skill
                    // base through the vitae/enchantment-adjusted recompute
                    // (CEnchantmentRegistry::EnchantSkill) instead of writing
                    // MovementSkills directly — see the pseudocode doc §9.
                    character.Character.UpdateMovementSkillBase(
                        runSkill,
                        jumpSkill);
                    character.OnSkillsUpdated?.Invoke(runSkill, jumpSkill);
                    character.OnMovementStatsUpdated?.Invoke();
                },
                resolveSkillFormulaBonus: character.ResolveSkillFormulaBonus,
                onShortcuts: inventory.OnShortcuts,
                playerGuid: inventory.PlayerGuid,
                onUseDone: inventory.OnUseDone,
                onAppraisal: inventory.OnAppraisal,
                itemMana: inventory.ItemMana,
                onConfirmationRequest: character.OnConfirmationRequest,
                onConfirmationDone: character.OnConfirmationDone,
                friends: social.Friends,
                squelch: social.Squelch,
                onDesiredComponents: null,
                onCharacterOptions: character.Character.Options.Replace,
                clientTime: character.ClientTime,
                externalContainers: inventory.ExternalContainers,
                vendor: inventory.Vendor,
                accepting: IsAccepting));
            ConstructionCheckpoint();

            // Campaign P Slice P1 (2026-07-30): burden recompute triggers —
            // the SAME event set IndicatorBarController.UpdateBurden already
            // reacts to (Strength + augmentation property 0xE6 +
            // EncumbranceVal property 5, falling back to SumCarriedBurden).
            // See the pseudocode doc §9. Campaign P Slice P3 (2026-07-30)
            // rides the SAME triggers for the player's own PWD bitfield
            // (PK/PKLite/Impenetrable) and PlayerKillerStatus/
            // LastPkAttackTimestamp — all live on the SAME ClientObject row.
            SubscribeToRecompute<ClientObject>(
                h => inventory.Objects.ObjectAdded += h,
                h => inventory.Objects.ObjectAdded -= h,
                () => RecomputePlayerQualities(inventory, character));
            SubscribeToRecompute<ClientObject>(
                h => inventory.Objects.ObjectUpdated += h,
                h => inventory.Objects.ObjectUpdated -= h,
                () => RecomputePlayerQualities(inventory, character));
            SubscribeToRecompute<ClientObject>(
                h => inventory.Objects.ObjectRemoved += h,
                h => inventory.Objects.ObjectRemoved -= h,
                () => RecomputePlayerQualities(inventory, character));
            SubscribeToRecompute<ClientObjectMove>(
                h => inventory.Objects.ObjectMoved += h,
                h => inventory.Objects.ObjectMoved -= h,
                () => RecomputePlayerQualities(inventory, character));
            SubscribeToRecompute<uint>(
                h => inventory.Objects.ContainerContentsReplaced += h,
                h => inventory.Objects.ContainerContentsReplaced -= h,
                () => RecomputePlayerQualities(inventory, character));
            SubscribeParameterless(
                h => inventory.Objects.Cleared += h,
                h => inventory.Objects.Cleared -= h,
                () => RecomputePlayerQualities(inventory, character));
            Subscribe<LocalPlayerState.AttributeKind>(
                h => character.Character.LocalPlayer.AttributeChanged += h,
                h => character.Character.LocalPlayer.AttributeChanged -= h,
                kind =>
                {
                    if (kind == LocalPlayerState.AttributeKind.Strength)
                        RecomputeBurden(inventory, character);
                });
            SubscribeParameterless(
                h => character.Character.Spellbook.EnchantmentsChanged += h,
                h => character.Character.Spellbook.EnchantmentsChanged -= h,
                () => RecomputeBurden(inventory, character));

            // Current-stamina push — CACQualities::InqRunRate/InqJumpVelocity's
            // stamina==0 effective-skill-zeroing gate (pseudocode doc §5).
            Subscribe<LocalPlayerState.VitalKind>(
                h => character.Character.LocalPlayer.Changed += h,
                h => character.Character.LocalPlayer.Changed -= h,
                kind => RecomputeStamina(kind, character));

            _subscriptions.Add(new CombatChatTranslator(
                character.Combat,
                social.Chat,
                IsAccepting));
            ConstructionCheckpoint();

            Subscribe<HearSpeech.Parsed>(h => session.SpeechHeard += h, h => session.SpeechHeard -= h, speech =>
                social.Chat.OnLocalSpeech(
                    speech.SenderName,
                    speech.Text,
                    speech.SenderGuid,
                    speech.IsRanged));
            Subscribe<ServerMessage.Parsed>(
                h => session.ServerMessageReceived += h,
                h => session.ServerMessageReceived -= h,
                message => social.Chat.OnSystemMessage(message.Message, message.ChatType));
            Subscribe<EmoteText.Parsed>(h => session.EmoteHeard += h, h => session.EmoteHeard -= h, emote =>
                social.Chat.OnEmote(emote.SenderName, emote.Text, emote.SenderGuid));
            Subscribe<SoulEmote.Parsed>(h => session.SoulEmoteHeard += h, h => session.SoulEmoteHeard -= h, emote =>
                social.Chat.OnSoulEmote(emote.SenderName, emote.Text, emote.SenderGuid));
            Subscribe<PlayerKilled.Parsed>(
                h => session.PlayerKilledReceived += h,
                h => session.PlayerKilledReceived -= h,
                killed => social.Chat.OnPlayerKilled(
                    killed.DeathMessage,
                    killed.VictimGuid,
                    killed.KillerGuid));
            Subscribe<TurbineChat.Parsed>(
                h => session.TurbineChatReceived += h,
                h => session.TurbineChatReceived -= h,
                parsed => RouteTurbineChat(social.Chat, parsed));
            Subscribe<PrivateUpdateVital.ParsedFull>(h => session.VitalUpdated += h, h => session.VitalUpdated -= h, vital =>
                character.Character.LocalPlayer.OnVitalUpdate(
                    vital.VitalId,
                    vital.Ranks,
                    vital.Start,
                    vital.Xp,
                    vital.Current));
            Subscribe<PrivateUpdateVital.ParsedCurrent>(
                h => session.VitalCurrentUpdated += h,
                h => session.VitalCurrentUpdated -= h,
                vital => character.Character.LocalPlayer.OnVitalCurrent(
                    vital.VitalId,
                    vital.Current));

            if (Interlocked.CompareExchange(ref _lifecycleState, 2, 1) != 1)
                throw new ObjectDisposedException(nameof(LiveSessionEventRouter));
        }
        catch
        {
            Interlocked.Exchange(ref _accepting, 0);
            Interlocked.Exchange(ref _lifecycleState, 3);
            throw;
        }
    }

    public bool Accepting => IsAccepting();

    public void Dispose()
    {
        Interlocked.Exchange(ref _accepting, 0);
        Interlocked.Exchange(ref _lifecycleState, 3);
        _subscriptions.Dispose();
    }

    private void Subscribe<T>(
        Action<Action<T>> attach,
        Action<Action<T>> detach,
        Action<T> sink)
    {
        Action<T> handler = value =>
        {
            if (Volatile.Read(ref _accepting) != 0)
                sink(value);
        };

        attach(handler);
        // Add assumes cleanup ownership before it can call an external detach.
        // If the set is already closing, it retains/retries that exact edge;
        // calling detach again here would replay a successful removal.
        _subscriptions.Add(() => detach(handler));

        ConstructionCheckpoint();
    }

    /// <summary>
    /// Campaign P Slice P1 (2026-07-30): a payload-typed event whose ONLY
    /// job is "something relevant changed, recompute" — thin wrapper over
    /// <see cref="Subscribe{T}"/> that discards the payload.
    /// </summary>
    private void SubscribeToRecompute<T>(
        Action<Action<T>> attach,
        Action<Action<T>> detach,
        Action recompute) =>
        Subscribe(attach, detach, (T _) => recompute());

    /// <summary>
    /// Campaign P Slice P1 (2026-07-30): the parameterless-event analogue of
    /// <see cref="Subscribe{T}"/> (<c>ClientObjectTable.Cleared</c> carries
    /// no payload).
    /// </summary>
    private void SubscribeParameterless(
        Action<Action> attach,
        Action<Action> detach,
        Action sink)
    {
        Action handler = () =>
        {
            if (Volatile.Read(ref _accepting) != 0)
                sink();
        };

        attach(handler);
        _subscriptions.Add(() => detach(handler));

        ConstructionCheckpoint();
    }

    /// <summary>
    /// Campaign P Slice P1 (2026-07-30): retail <c>CACQualities::InqLoad</c>
    /// equivalent (Strength + augmentation property 0xE6 + EncumbranceVal
    /// property 5, falling back to the summed carried burden) — the SAME
    /// input assembly <c>IndicatorBarController.UpdateBurden</c> /
    /// <c>InventoryController.RefreshBurden</c> already use for the burden
    /// HUD. See the pseudocode doc §2/§9.
    /// </summary>
    private static void RecomputeBurden(
        LiveInventorySessionBindings inventory,
        LiveCharacterSessionBindings character,
        bool notify = true)
    {
        uint player = inventory.PlayerGuid();
        ClientObject? playerObject = inventory.Objects.Get(player);
        int strength = character.Character.LocalPlayer
            .GetEffectiveAttribute(LocalPlayerState.AttributeKind.Strength) ?? 0;
        int aug = playerObject?.Properties.GetInt(
            (uint)PropertyInt.AugmentationIncreasedCarryingCapacity) ?? 0;
        int capacity = EncumbranceSystem.EncumbranceCapacity(strength, aug);
        int burden = playerObject is not null
            && playerObject.Properties.Ints.TryGetValue(
                (uint)PropertyInt.EncumbranceVal, out int wireBurden)
                ? wireBurden
                : inventory.Objects.SumCarriedBurden(player);
        float load = EncumbranceSystem.Load(capacity, burden);
        character.Character.MovementSkills.UpdateBurden(load);
        if (notify)
            character.OnMovementStatsUpdated?.Invoke();
    }

    private static void RecomputePlayerQualities(
        LiveInventorySessionBindings inventory,
        LiveCharacterSessionBindings character)
    {
        RecomputeBurden(inventory, character, notify: false);
        RecomputePvpStatus(inventory, character, notify: false);

        uint player = inventory.PlayerGuid();
        PropertyBundle properties = inventory.Objects.Get(player)?.Properties
            ?? character.Character.LocalPlayer.Properties;
        character.Character.UpdateMovementSkillAugmentations(
            PlayerSkillMath.AugmentationBonuses.FromProperties(properties));
        character.OnMovementStatsUpdated?.Invoke();
    }

    /// <summary>
    /// TS-23 (Campaign P Slice P3, 2026-07-30): pushes the local player's
    /// own <c>PublicWeenieDesc._bitfield</c> (PK/PKLite/Impenetrable
    /// collision-exemption bits, already parsed at CreateObject time — see
    /// <c>CreateObject.cs</c>'s <c>objectDescriptionFlags</c> read) and the
    /// raw <c>PlayerKillerStatus</c>(0x86)/<c>LastPkAttackTimestamp</c>(0x91)
    /// pair (retail <c>CACQualities::JumpStaminaCost</c>'s PK-timer bump)
    /// into <see cref="RuntimeMovementSkillState"/>. Rides the SAME
    /// ClientObject add/update/move/clear events <see cref="RecomputeBurden"/>
    /// already reacts to — both live on the player's own row.
    /// </summary>
    private static void RecomputePvpStatus(
        LiveInventorySessionBindings inventory,
        LiveCharacterSessionBindings character,
        bool notify = true)
    {
        uint player = inventory.PlayerGuid();
        ClientObject? playerObject = inventory.Objects.Get(player);
        uint bitfield = playerObject?.PublicWeenieBitfield ?? 0u;
        int pkStatus = playerObject?.Properties.Ints.TryGetValue(
            (uint)PropertyInt.PlayerKillerStatus, out int wirePkStatus) == true
            ? wirePkStatus
            : -1;
        float? lastPkAttackTimestamp =
            playerObject?.Properties.Floats.TryGetValue(
                (uint)PropertyFloat.LastPkAttackTimestamp, out double wireTimestamp) == true
                ? (float)wireTimestamp
                : null;
        character.Character.MovementSkills.UpdateOwnPwdBitfield(bitfield);
        character.Character.MovementSkills.UpdatePlayerKillerStatus(
            pkStatus,
            lastPkAttackTimestamp);
        if (notify)
            character.OnMovementStatsUpdated?.Invoke();
    }

    /// <summary>
    /// Campaign P Slice P1 (2026-07-30): pushes current-stamina vital
    /// changes into <see cref="RuntimeMovementSkillState"/> — feeds
    /// <c>CACQualities::InqRunRate</c>/<c>InqJumpVelocity</c>'s stamina==0
    /// effective-skill-zeroing gate (pseudocode doc §5).
    /// </summary>
    private static void RecomputeStamina(
        LocalPlayerState.VitalKind kind,
        LiveCharacterSessionBindings character)
    {
        if (kind != LocalPlayerState.VitalKind.Stamina) return;
        if (character.Character.LocalPlayer.Get(LocalPlayerState.VitalKind.Stamina)
            is not LocalPlayerState.VitalSnapshot stamina)
        {
            return;
        }

        character.Character.MovementSkills.UpdateStamina((int)stamina.Current);
        character.OnMovementStatsUpdated?.Invoke();
    }

    private void ConstructionCheckpoint() =>
        _constructionCheckpoint?.Invoke(++_constructionStep);

    private bool IsAccepting() => Volatile.Read(ref _accepting) != 0;

    private static void RouteTurbineChat(ChatLog chat, TurbineChat.Parsed parsed)
    {
        if (parsed.Body is not TurbineChat.Payload.EventSendToRoom message)
            return;

        chat.OnChannelBroadcast(
            message.RoomId,
            message.SenderName,
            message.Message,
            TurbineChatDisplayNames.Resolve(message.RoomId, message.ChatType));
    }

    private static void Validate(
        LiveEntitySessionSink entities,
        LiveEnvironmentSessionSink environment,
        LiveInventorySessionBindings inventory,
        LiveCharacterSessionBindings character,
        LiveSocialSessionBindings social)
    {
        ArgumentNullException.ThrowIfNull(entities);
        ArgumentNullException.ThrowIfNull(environment);
        ArgumentNullException.ThrowIfNull(inventory);
        ArgumentNullException.ThrowIfNull(character);
        ArgumentNullException.ThrowIfNull(social);
        ArgumentNullException.ThrowIfNull(entities.Spawned);
        ArgumentNullException.ThrowIfNull(entities.Deleted);
        ArgumentNullException.ThrowIfNull(entities.PickedUp);
        ArgumentNullException.ThrowIfNull(entities.MotionUpdated);
        ArgumentNullException.ThrowIfNull(entities.PositionUpdated);
        ArgumentNullException.ThrowIfNull(entities.VectorUpdated);
        ArgumentNullException.ThrowIfNull(entities.StateUpdated);
        ArgumentNullException.ThrowIfNull(entities.ParentUpdated);
        ArgumentNullException.ThrowIfNull(entities.TeleportStarted);
        ArgumentNullException.ThrowIfNull(entities.AppearanceUpdated);
        ArgumentNullException.ThrowIfNull(entities.PlayPhysicsScript);
        ArgumentNullException.ThrowIfNull(entities.PlayPhysicsScriptType);
        ArgumentNullException.ThrowIfNull(entities.SoundEvent);
        ArgumentNullException.ThrowIfNull(environment.EnvironChanged);
        ArgumentNullException.ThrowIfNull(environment.ServerTimeUpdated);
        ArgumentNullException.ThrowIfNull(inventory.Objects);
        ArgumentNullException.ThrowIfNull(inventory.PlayerGuid);
        ArgumentNullException.ThrowIfNull(character.Combat);
        ArgumentNullException.ThrowIfNull(character.Character);
        ArgumentNullException.ThrowIfNull(social.Chat);
        ArgumentNullException.ThrowIfNull(social.TurbineChat);
    }
}

internal sealed class LiveSessionSubscriptionSet : IDisposable
{
    private readonly object _gate = new();
    private readonly List<RetryableSubscription> _subscriptions = [];
    private bool _disposeRequested;

    public void Add(IDisposable subscription)
    {
        ArgumentNullException.ThrowIfNull(subscription);
        AddRetained(new RetryableSubscription(subscription.Dispose));
    }

    public void Add(Action unsubscribe)
    {
        ArgumentNullException.ThrowIfNull(unsubscribe);
        AddRetained(new RetryableSubscription(unsubscribe));
    }

    private void AddRetained(RetryableSubscription retained)
    {
        bool disposeNow;
        lock (_gate)
        {
            disposeNow = _disposeRequested;
            _subscriptions.Add(retained);
        }

        if (!disposeNow)
            return;
        retained.Dispose();
        throw new ObjectDisposedException(nameof(LiveSessionSubscriptionSet));
    }

    public void Dispose()
    {
        RetryableSubscription[] subscriptions;
        lock (_gate)
        {
            _disposeRequested = true;
            subscriptions = _subscriptions.ToArray();
        }

        List<Exception>? errors = null;
        for (int index = subscriptions.Length - 1; index >= 0; index--)
        {
            try
            {
                subscriptions[index].Dispose();
            }
            catch (Exception error)
            {
                (errors ??= []).Add(error);
            }
        }

        if (errors is not null)
            throw new AggregateException(
                "one or more live-session subscriptions failed to detach",
                errors);
    }

    private sealed class RetryableSubscription(Action dispose) : IDisposable
    {
        private readonly object _gate = new();
        private Action? _dispose = dispose;
        private bool _executing;
        private int _executingThreadId;

        public void Dispose()
        {
            Action? operation;
            int threadId = Environment.CurrentManagedThreadId;
            lock (_gate)
            {
                while (_executing)
                {
                    if (_executingThreadId == threadId)
                    {
                        throw new InvalidOperationException(
                            "Live-session subscription cleanup cannot complete reentrantly.");
                    }
                    Monitor.Wait(_gate);
                }

                operation = _dispose;
                if (operation is null)
                    return;
                _executing = true;
                _executingThreadId = threadId;
            }

            try
            {
                operation();
            }
            catch
            {
                CompleteAttempt(succeeded: false);
                throw;
            }

            CompleteAttempt(succeeded: true);
        }

        private void CompleteAttempt(bool succeeded)
        {
            lock (_gate)
            {
                if (succeeded)
                    _dispose = null;
                _executing = false;
                _executingThreadId = 0;
                Monitor.PulseAll(_gate);
            }
        }
    }
}