using System.Collections.Generic;
using System.Numerics;
using AcDream.App.Rendering.Vfx;
using AcDream.Core.Physics;
using AcDream.Core.Vfx;
using AcDream.Core.World;
using DatReaderWriter.Types;
using Xunit;
using DatPhysicsScript = DatReaderWriter.DBObjs.PhysicsScript;

namespace AcDream.Core.Tests.Rendering.Vfx;

public sealed class EntityScriptActivatorTests
{
    /// <summary>Recording sink so we can assert which hooks the runner fires.</summary>
    private sealed class RecordingSink : IAnimationHookSink
    {
        public List<(uint EntityId, Vector3 Pos, AnimationHook Hook)> Calls = new();
        public void OnHook(uint entityId, Vector3 worldPos, AnimationHook hook)
            => Calls.Add((entityId, worldPos, hook));
    }

    private static DatPhysicsScript BuildScript(params (double time, AnimationHook hook)[] items)
    {
        var script = new DatPhysicsScript();
        foreach (var (t, h) in items)
            script.ScriptData.Add(new PhysicsScriptData { StartTime = t, Hook = h });
        return script;
    }

    private static WorldEntity MakeEntity(uint serverGuid, Vector3 position) =>
        new()
        {
            Id = serverGuid,
            ServerGuid = serverGuid,
            SourceGfxObjOrSetupId = 0x02000001u,
            Position = position,
            Rotation = Quaternion.Identity,
            MeshRefs = System.Array.Empty<MeshRef>(),
        };

    private record Pipeline(
        ParticleSystem System,
        ParticleHookSink Sink,
        PhysicsScriptRunner Runner,
        RecordingSink Recording);

    private static Pipeline BuildPipeline(params (uint id, DatPhysicsScript script)[] scripts)
    {
        var registry = new EmitterDescRegistry();
        var system = new ParticleSystem(registry);
        var hookSink = new ParticleHookSink(system);          // for activator's StopAllForEntity
        var recording = new RecordingSink();                  // for runner's hook dispatch
        var table = new Dictionary<uint, DatPhysicsScript>();
        foreach (var (id, s) in scripts) table[id] = s;
        var runner = new PhysicsScriptRunner(
            id => table.TryGetValue(id, out var s) ? s : null,
            recording);
        return new Pipeline(system, hookSink, runner, recording);
    }

    [Fact]
    public void OnCreate_WithDefaultScript_FiresRunnerWithEntityGuidAndPosition()
    {
        var p = BuildPipeline(
            (0xAAu, BuildScript((0.0, new CreateParticleHook { EmitterInfoId = 100 }))));
        var activator = new EntityScriptActivator(p.Runner, p.Sink, _ => 0xAAu);
        var entity = MakeEntity(serverGuid: 0xCAFEu, position: new Vector3(1, 2, 3));

        activator.OnCreate(entity);

        Assert.Equal(1, p.Runner.ActiveScriptCount);
        p.Runner.Tick(0.001f);
        Assert.Single(p.Recording.Calls);
        Assert.Equal(0xCAFEu, p.Recording.Calls[0].EntityId);
        Assert.Equal(new Vector3(1, 2, 3), p.Recording.Calls[0].Pos);
    }

    [Fact]
    public void OnCreate_WithoutDefaultScript_DoesNothing()
    {
        var p = BuildPipeline();   // no scripts registered
        var activator = new EntityScriptActivator(p.Runner, p.Sink, _ => 0u);
        var entity = MakeEntity(serverGuid: 0xCAFEu, position: Vector3.Zero);

        activator.OnCreate(entity);

        Assert.Equal(0, p.Runner.ActiveScriptCount);
        Assert.Empty(p.Recording.Calls);
    }

    [Fact]
    public void OnRemove_StopsScriptsAndEmitters()
    {
        var p = BuildPipeline(
            (0xAAu, BuildScript((0.0, new CreateParticleHook { EmitterInfoId = 100 }))));
        var activator = new EntityScriptActivator(p.Runner, p.Sink, _ => 0xAAu);
        var entity = MakeEntity(serverGuid: 0xCAFEu, position: Vector3.Zero);

        activator.OnCreate(entity);
        Assert.Equal(1, p.Runner.ActiveScriptCount);

        activator.OnRemove(0xCAFEu);

        Assert.Equal(0, p.Runner.ActiveScriptCount);
        // Tick after Remove must not surface any further hook fires.
        p.Runner.Tick(1.0f);
        Assert.Empty(p.Recording.Calls);
    }
}