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

namespace AcDream.Core.Tests.Vfx;

public sealed class PhysicsScriptRunnerTests
{
    /// <summary>
    /// Recording sink so tests can assert each hook dispatch.
    /// </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 CreateParticleHook CreateHook(uint emitterInfoId)
        => new CreateParticleHook { EmitterInfoId = emitterInfoId };

    private static PhysicsScriptRunner MakeRunner(RecordingSink sink, params (uint id, DatPhysicsScript script)[] scripts)
    {
        // Build an in-memory resolver from the script table — no DatCollection needed.
        var table = new Dictionary<uint, DatPhysicsScript>();
        foreach (var (id, s) in scripts) table[id] = s;
        return new PhysicsScriptRunner(
            id => table.TryGetValue(id, out var s) ? s : null,
            sink);
    }

    [Fact]
    public void Play_UnknownScript_ReturnsFalse()
    {
        var sink = new RecordingSink();
        var runner = MakeRunner(sink);  // no scripts registered
        Assert.False(runner.Play(0xDEADBEEF, entityId: 1, anchorWorldPos: Vector3.Zero));
        Assert.Empty(sink.Calls);
    }

    [Fact]
    public void Play_ZeroScriptId_IgnoredSilently()
    {
        var sink = new RecordingSink();
        var runner = MakeRunner(sink);
        Assert.False(runner.Play(0, entityId: 1, anchorWorldPos: Vector3.Zero));
        Assert.Equal(0, runner.ActiveScriptCount);
    }

    [Fact]
    public void HooksFire_InOrder_AtScheduledTimes()
    {
        var script = BuildScript(
            (0.0, CreateHook(100)),
            (0.5, CreateHook(101)),
            (1.0, CreateHook(102)));

        var sink = new RecordingSink();
        var runner = MakeRunner(sink, (0xAAu, script));
        runner.Play(scriptId: 0xAA, entityId: 0x7, anchorWorldPos: new Vector3(1, 2, 3));

        runner.Tick(0.25f);
        Assert.Single(sink.Calls);
        Assert.Equal(100u, ((CreateParticleHook)sink.Calls[0].Hook).EmitterInfoId.DataId);

        runner.Tick(0.35f);  // total 0.6
        Assert.Equal(2, sink.Calls.Count);
        Assert.Equal(101u, ((CreateParticleHook)sink.Calls[1].Hook).EmitterInfoId.DataId);

        runner.Tick(0.9f);   // total 1.5
        Assert.Equal(3, sink.Calls.Count);
        Assert.Equal(102u, ((CreateParticleHook)sink.Calls[2].Hook).EmitterInfoId.DataId);
        Assert.Equal(0, runner.ActiveScriptCount);   // fully consumed
    }

    [Fact]
    public void EntityIdAndAnchor_ArePassedThrough()
    {
        var script = BuildScript((0.0, CreateHook(1)));
        var sink = new RecordingSink();
        var runner = MakeRunner(sink, (0xAAu, script));

        var anchor = new Vector3(123, 45, 67);
        runner.Play(scriptId: 0xAA, entityId: 0xCAFE, anchorWorldPos: anchor);
        runner.Tick(0.1f);

        Assert.Single(sink.Calls);
        Assert.Equal(0xCAFEu, sink.Calls[0].EntityId);
        Assert.Equal(anchor,  sink.Calls[0].Pos);
    }

    [Fact]
    public void Replay_SameScriptSameEntity_Replaces_DoesNotStack()
    {
        var script = BuildScript(
            (0.0, CreateHook(1)),
            (1.0, CreateHook(2)));

        var sink = new RecordingSink();
        var runner = MakeRunner(sink, (0xAAu, script));

        runner.Play(scriptId: 0xAA, entityId: 1, anchorWorldPos: Vector3.Zero);
        runner.Tick(0.1f);
        Assert.Single(sink.Calls);

        // Re-play — the old instance should be replaced, not stacked.
        runner.Play(scriptId: 0xAA, entityId: 1, anchorWorldPos: Vector3.Zero);
        Assert.Equal(1, runner.ActiveScriptCount);
        runner.Tick(0.1f);
        Assert.Equal(2, sink.Calls.Count);
        // Hook 0 fires AGAIN (fresh timeline from t=0), not hook 1.
        Assert.Equal(1u, ((CreateParticleHook)sink.Calls[1].Hook).EmitterInfoId.DataId);
    }

    [Fact]
    public void Replay_DifferentEntities_BothActiveConcurrently()
    {
        var script = BuildScript((0.0, CreateHook(42)));
        var sink = new RecordingSink();
        var runner = MakeRunner(sink, (0xAAu, script));

        runner.Play(scriptId: 0xAA, entityId: 0x1, anchorWorldPos: new Vector3(1, 0, 0));
        runner.Play(scriptId: 0xAA, entityId: 0x2, anchorWorldPos: new Vector3(2, 0, 0));
        Assert.Equal(2, runner.ActiveScriptCount);

        runner.Tick(0.1f);
        Assert.Equal(2, sink.Calls.Count);
        Assert.Contains(sink.Calls, c => c.EntityId == 1u);
        Assert.Contains(sink.Calls, c => c.EntityId == 2u);
    }

    [Fact]
    public void StopAllForEntity_CancelsEntityScripts_LeavesOthers()
    {
        var script = BuildScript(
            (0.0, CreateHook(1)),
            (1.0, CreateHook(2)));

        var sink = new RecordingSink();
        var runner = MakeRunner(sink, (0xAAu, script));

        runner.Play(scriptId: 0xAA, entityId: 1, anchorWorldPos: Vector3.Zero);
        runner.Play(scriptId: 0xAA, entityId: 2, anchorWorldPos: Vector3.Zero);
        runner.Tick(0.1f);   // both fire hook 0
        Assert.Equal(2, sink.Calls.Count);

        runner.StopAllForEntity(1);
        Assert.Equal(1, runner.ActiveScriptCount);
        runner.Tick(2.0f);   // only entity 2's script should fire hook 1
        Assert.Equal(3, sink.Calls.Count);
        Assert.Equal(2u, sink.Calls[^1].EntityId);
    }

    [Fact]
    public void CallPES_NestedScript_SpawnsOnSameEntity()
    {
        var outer = BuildScript((0.0, new CallPESHook { PES = 0xBB, Pause = 0f }));
        var inner = BuildScript((0.0, CreateHook(99)));

        var sink = new RecordingSink();
        var runner = MakeRunner(sink, (0xAAu, outer), (0xBBu, inner));
        runner.Play(scriptId: 0xAA, entityId: 0x7, anchorWorldPos: new Vector3(1, 2, 3));

        // First tick fires the CallPES hook. Inner script gets queued to
        // _active but does NOT fire this tick (we iterate _active
        // backwards, and the inner is appended AFTER the current index) —
        // matches retail's linked-list insertion semantics. Inner fires
        // on the NEXT tick instead.
        runner.Tick(0.1f);
        Assert.Empty(sink.Calls);        // CallPES handled inline, no direct sink hit
        Assert.Equal(1, runner.ActiveScriptCount);  // inner is queued, outer done

        // Second tick — inner's hook at t=0 fires now.
        runner.Tick(0.1f);
        Assert.Single(sink.Calls);
        Assert.Equal(99u, ((CreateParticleHook)sink.Calls[0].Hook).EmitterInfoId.DataId);
        Assert.Equal(0x7u, sink.Calls[0].EntityId);
    }

    [Fact]
    public void CallPES_WithPause_DelaysSubScript()
    {
        var outer = BuildScript((0.0, new CallPESHook { PES = 0xBB, Pause = 0.5f }));
        var inner = BuildScript((0.0, CreateHook(99)));

        var sink = new RecordingSink();
        var runner = MakeRunner(sink, (0xAAu, outer), (0xBBu, inner));
        runner.Play(scriptId: 0xAA, entityId: 0x7, anchorWorldPos: Vector3.Zero);

        // CallPES fires immediately, but inner script's hook is gated by Pause.
        runner.Tick(0.1f);
        Assert.Empty(sink.Calls);  // inner hook waiting on Pause=0.5s

        runner.Tick(0.5f);  // total 0.6 > 0.5 pause
        Assert.Single(sink.Calls);
    }

    [Fact]
    public void CallPES_SelfLoopWithPause_DoesNotReplaceCurrentInstance()
    {
        var script = BuildScript(
            (0.0, new CallPESHook { PES = 0xAA, Pause = 30f }),
            (0.0, CreateHook(123)));

        var sink = new RecordingSink();
        var runner = MakeRunner(sink, (0xAAu, script));
        runner.Play(scriptId: 0xAA, entityId: 0x7, anchorWorldPos: Vector3.Zero);

        runner.Tick(0.1f);

        Assert.Single(sink.Calls);
        Assert.Equal(123u, ((CreateParticleHook)sink.Calls[0].Hook).EmitterInfoId.DataId);
        Assert.Equal(1, runner.ActiveScriptCount);

        runner.Tick(29.8f);
        Assert.Single(sink.Calls);

        runner.Tick(0.3f);
        Assert.Equal(2, sink.Calls.Count);
    }
}