using System.Numerics;
using AcDream.Core.Vfx;
using AcDream.Core.World;

namespace AcDream.App.Rendering.Vfx;

/// <summary>
/// Setup script/profile data resolved once when a logical effect owner is
/// registered. Part transforms are indexed and root-local.
/// </summary>
public sealed record ScriptActivationInfo(
    uint ScriptId,
    IReadOnlyList<Matrix4x4> PartTransforms,
    EntityEffectProfile? EffectProfile = null,
    IReadOnlyList<bool>? PartAvailability = null);

/// <summary>
/// Owns create-time Setup script activation and its symmetric teardown for
/// live and DAT-static entities.
/// </summary>
/// <remarks>
/// Setup <c>DefaultScript</c> is a direct PES played during Setup
/// initialization. Live registration invokes this class once per logical
/// generation; spatial rebucketing never replays it.
/// </remarks>
public sealed class EntityScriptActivator
{
    private readonly PhysicsScriptRunner _scriptRunner;
    private readonly ParticleHookSink _particleSink;
    private readonly EntityEffectPoseRegistry _poses;
    private readonly Func<WorldEntity, ScriptActivationInfo?> _resolver;
    private readonly Action<uint, WorldEntity, EntityEffectProfile>? _registerDatStaticEffectOwner;
    private readonly Action<uint>? _unregisterDatStaticEffectOwner;
    private readonly Dictionary<uint, WorldEntity> _activeStaticOwners = new();

    public EntityScriptActivator(
        PhysicsScriptRunner scriptRunner,
        ParticleHookSink particleSink,
        EntityEffectPoseRegistry poses,
        Func<WorldEntity, ScriptActivationInfo?> resolver,
        Action<uint, WorldEntity, EntityEffectProfile>? registerDatStaticEffectOwner = null,
        Action<uint>? unregisterDatStaticEffectOwner = null)
    {
        _scriptRunner = scriptRunner ?? throw new ArgumentNullException(nameof(scriptRunner));
        _particleSink = particleSink ?? throw new ArgumentNullException(nameof(particleSink));
        _poses = poses ?? throw new ArgumentNullException(nameof(poses));
        _resolver = resolver ?? throw new ArgumentNullException(nameof(resolver));
        _registerDatStaticEffectOwner = registerDatStaticEffectOwner;
        _unregisterDatStaticEffectOwner = unregisterDatStaticEffectOwner;
    }

    public void OnCreate(WorldEntity entity)
    {
        ArgumentNullException.ThrowIfNull(entity);
        uint key = entity.Id;
        if (key == 0)
            return;

        if (entity.ServerGuid == 0
            && _activeStaticOwners.TryGetValue(key, out WorldEntity? existing))
        {
            if (ReferenceEquals(existing, entity))
                return;
            throw new InvalidOperationException(
                $"Dat-static WorldEntity id 0x{key:X8} is already active; static allocators must be globally unique.");
        }

        ScriptActivationInfo? info = _resolver(entity);
        if (info is null)
            return;

        // Particle::Init (0x0051C930) samples the current root/part frames.
        // Publish before the Setup default script can execute; effects never
        // fall back to the camera or a cached spawn anchor.
        _poses.Publish(entity, info.PartTransforms, info.PartAvailability);

        if (entity.ServerGuid == 0)
            _activeStaticOwners.Add(key, entity);

        if (entity.ServerGuid == 0 && info.EffectProfile is { } profile)
            _registerDatStaticEffectOwner?.Invoke(key, entity, profile);

        if (info.ScriptId != 0)
            _scriptRunner.Play(info.ScriptId, key, entity.Position);
    }

    public void OnRemove(WorldEntity entity)
    {
        ArgumentNullException.ThrowIfNull(entity);
        uint key = entity.Id;
        if (key == 0)
            return;

        if (entity.ServerGuid == 0
            && (!_activeStaticOwners.TryGetValue(key, out WorldEntity? existing)
                || !ReferenceEquals(existing, entity)))
        {
            return;
        }

        _scriptRunner.StopAllForEntity(key);
        _particleSink.StopAllForEntity(key, fadeOut: false);
        _poses.Remove(key);
        if (entity.ServerGuid == 0 && _activeStaticOwners.Remove(key))
            _unregisterDatStaticEffectOwner?.Invoke(key);
    }
}