using System.Numerics;
using AcDream.App.Rendering;
using AcDream.App.Rendering.Gpu;
using AcDream.App.Rendering.Gpu.Vk;
using AcDream.App.Rendering.Wb;
using AcDream.App.Tests.Rendering.Gpu;
using AcDream.Content;
using Chorizite.Core.Render.Enums;
using Microsoft.Extensions.Logging.Abstractions;
using CullMode = DatReaderWriter.Enums.CullMode;

namespace AcDream.App.Tests.Rendering;

/// <summary>
/// S4-c2 final EnvCell production-dispatch pins: exact retained per-batch mask,
/// one token per (cell,list), separate list-filtered replay sources, immediate
/// detail turns, interleaving, and warmed allocation behavior.
/// </summary>
public sealed class EnvCellAlphaDrawSourceTests
{
    /// <summary>
    /// Canonical F4180104 surface 08000BFF's pure Base1ClipMap mask 0x08
    /// reaches CLIP while alpha-family 0x02 reaches ALPHA. Mutation check:
    /// hardcoding MaskAlphaFamily in the production batch classifier makes
    /// the first assertion report Alpha instead of Clip.</summary>
    [Fact]
    public void RetainedPerBatchMask_RoutesClipAndAlphaExactly()
    {
        var clip = new ObjectRenderBatch { IsTransparent = true, RetailSurfaceMask = 0x08 };
        var alpha = new ObjectRenderBatch { IsTransparent = true, RetailSurfaceMask = 0x02 };

        Assert.Equal(
            EnvCellTransparentRoute.Clip,
            EnvCellRenderer.RouteTransparentBatch(clip, detailSurfaceActive: false));
        Assert.Equal(
            EnvCellTransparentRoute.Alpha,
            EnvCellRenderer.RouteTransparentBatch(alpha, detailSurfaceActive: false));
    }

    /// <summary>
    /// A mixed cell creates one token in each list and neither set draws before
    /// the real queue drain. CLIP drains first and receives only the CLIP
    /// replay filter; ALPHA receives only ALPHA. Mutation checks: inverting the
    /// detail-off immediate predicate makes <c>Assert.Empty(log)</c> fail;
    /// removing the replay filter makes either route assertion fail.</summary>
    [Fact]
    public void MixedCell_DefersOneTokenPerList_AndReplayIsListFiltered()
    {
        using var fixture = new ProductionEnvCellFixture(
            detailSurfaceActive: false,
            0x08,
            0x02);
        EnvCellTransparentRoute routes = fixture.Renderer.GetTransparentRoutes(
            ProductionEnvCellFixture.CellId,
            detailSurfaceActive: false);

        fixture.Queue.BeginFrame();
        RetailPViewPassExecutor.DispatchTransparentCellShell(
            ProductionEnvCellFixture.CellId,
            routes,
            detailSurfaceActive: false,
            fixture.Queue,
            fixture.ClipSource,
            fixture.AlphaSource,
            fixture.ImmediateSink);

        Assert.Equal(EnvCellTransparentRoute.Clip | EnvCellTransparentRoute.Alpha, routes);
        Assert.Empty(fixture.Device.Calls.OfType<GpuRecordedMultiDrawIndirect>());
        Assert.Equal(1, fixture.Queue.ClipCount);
        Assert.Equal(1, fixture.Queue.AlphaCount);

        fixture.Queue.Flush(RetailAlphaFlushSite.DrawBuilding, 0f);

        GpuRecordedMultiDrawIndirect[] draws =
            [.. fixture.Device.Calls.OfType<GpuRecordedMultiDrawIndirect>()];
        Assert.Equal(2, draws.Length);
        Assert.All(draws, static draw => Assert.Equal(1u, draw.DrawCount));
        fixture.Queue.EndFrame();
    }

    [Fact]
    public void DetailOn_DrawsAtCellTurnWithDetail_AndQueuesNothing()
    {
        using var fixture = new ProductionEnvCellFixture(
            detailSurfaceActive: true,
            0x08);
        EnvCellTransparentRoute routes = fixture.Renderer.GetTransparentRoutes(
            ProductionEnvCellFixture.CellId,
            detailSurfaceActive: true);
        fixture.Queue.BeginFrame();

        RetailPViewPassExecutor.DispatchTransparentCellShell(
            ProductionEnvCellFixture.CellId,
            routes,
            detailSurfaceActive: true,
            fixture.Queue,
            fixture.ClipSource,
            fixture.AlphaSource,
            fixture.ImmediateSink);

        Assert.Equal(EnvCellTransparentRoute.Immediate, routes);
        Assert.Equal(1, fixture.ImmediateSink.DrawCount);
        Assert.True(fixture.ImmediateSink.LastDetailSurfaceActive);
        Assert.Equal(2, fixture.Device.Calls.OfType<GpuRecordedMultiDrawIndirect>().Count());
        Assert.Equal(0, fixture.Queue.PendingCount);
        fixture.Queue.EndFrame();
        Assert.Equal(1, fixture.ImmediateSink.DrawCount);
    }

    /// <summary>Two cell tokens from the SAME <see cref="RetailPViewPassExecutor.EnvCellAlphaDrawSource"/>,
    /// with an unrelated source's entry appended between them, must still
    /// produce TWO separate single-cell draw calls around the interposed
    /// entry — <see cref="IRetailAlphaDrawSource"/>'s "only adjacent
    /// same-source entries batch" invariant (the queue never groups across
    /// another entry, which is what keeps compositing order exact). Mutation
    /// check: an implementation that draws every prepared cell id in one
    /// call regardless of the requested <c>(first, count)</c> range would
    /// print both cell ids together on EACH of the two
    /// <c>DrawPreparedAlphaBatch</c> invocations instead of once each — the
    /// exact sequence assertion below fails against that mutation.</summary>
    [Fact]
    public void ParticleAppendedBetweenTwoCellTokens_KeepsItsPositionInTheCombinedDrain()
    {
        var log = new List<string>();
        var clipSource = Source(EnvCellTransparentRoute.Clip, log);
        var cellSource = Source(EnvCellTransparentRoute.Alpha, log);
        var particleSource = new RecordingSource("particle", log);
        var queue = new RetailAlphaQueue();

        queue.BeginFrame();
        RetailPViewPassExecutor.DispatchTransparentCellShell(
            0x100u, EnvCellTransparentRoute.Alpha, false, queue,
            clipSource, cellSource, (_, _, _) => throw new InvalidOperationException());
        Assert.True(queue.TryAppend(RetailAlphaList.Alpha, particleSource, 7, false));
        RetailPViewPassExecutor.DispatchTransparentCellShell(
            0x200u, EnvCellTransparentRoute.Alpha, false, queue,
            clipSource, cellSource, (_, _, _) => throw new InvalidOperationException());
        queue.EndFrame();

        Assert.Equal(new[] { "Alpha:00000100", "particle:7", "Alpha:00000200" }, log);
    }

    [Fact]
    public void ProductionDispatch_WarmedImmediateAndFilteredSourcesDoNotAllocate()
    {
        var sink = new NoAllocRouteSink();
        var clipSource = new RetailPViewPassExecutor.EnvCellAlphaDrawSource(
            sink.Render,
            EnvCellTransparentRoute.Clip);
        var alphaSource = new RetailPViewPassExecutor.EnvCellAlphaDrawSource(
            sink.Render,
            EnvCellTransparentRoute.Alpha);
        RetailPViewPassExecutor.RenderImmediateEnvCellRoute immediate = sink.DrawImmediate;
        var queue = new RetailAlphaQueue();

        for (int i = 0; i < 64; i++)
            RunMixed(queue, clipSource, alphaSource, immediate);

        long before = GC.GetAllocatedBytesForCurrentThread();
        for (int i = 0; i < 1_000; i++)
            RunMixed(queue, clipSource, alphaSource, immediate);
        long allocated = GC.GetAllocatedBytesForCurrentThread() - before;

        Assert.Equal(0, allocated);
    }

    private static void RunMixed(
        RetailAlphaQueue queue,
        RetailPViewPassExecutor.EnvCellAlphaDrawSource clipSource,
        RetailPViewPassExecutor.EnvCellAlphaDrawSource alphaSource,
        RetailPViewPassExecutor.RenderImmediateEnvCellRoute immediate)
    {
        queue.BeginFrame();
        RetailPViewPassExecutor.DispatchTransparentCellShell(
            0xF4180104u,
            EnvCellTransparentRoute.Immediate
                | EnvCellTransparentRoute.Clip
                | EnvCellTransparentRoute.Alpha,
            detailSurfaceActive: false,
            queue,
            clipSource,
            alphaSource,
            immediate);
        queue.EndFrame();
    }

    private static RetailPViewPassExecutor.EnvCellAlphaDrawSource Source(
        EnvCellTransparentRoute expectedRoute,
        List<string> log) =>
        new(
            (cells, route, detail) =>
            {
                Assert.Equal(expectedRoute, route);
                Assert.False(detail);
                for (int i = 0; i < cells.Count; i++)
                    log.Add($"{route}:{cells[i]:X8}");
            },
            expectedRoute);

    /// <summary>
    /// Recording-GPU fixture for the production EnvCell scan, dispatch and
    /// filtered replay path. The two retained masks enter through the real
    /// Content upload boundary, not through hand-built App batches.
    /// </summary>
    private sealed class ProductionEnvCellFixture : IDisposable
    {
        public const uint CellId = 0xF4180104u;
        private const ulong MeshId = 0x2_F4180104UL;

        private readonly GpuDeviceFrameLifetime _frames;
        private readonly VulkanWorldPassScope _scope;
        private readonly ObjectMeshManager _meshManager;
        private readonly IGpuPassEncoder _pass;
        private readonly IDisposable _publication;

        public ProductionEnvCellFixture(
            bool detailSurfaceActive,
            params byte[] retainedMasks)
        {
            Device = new RecordingGpuDevice();
            _frames = new GpuDeviceFrameLifetime(Device);
            _scope = new VulkanWorldPassScope(sampleCount: 1);
            _meshManager = new ObjectMeshManager(
                new VulkanMeshPipelineDevice(Device.Retirement),
                Device,
                new NullPreparedAssetSource(),
                NullLogger<ObjectMeshManager>.Instance);

            var mesh = new ObjectMeshData
            {
                ObjectId = MeshId,
                Vertices =
                [
                    new VertexPositionNormalTexture { Position = new Vector3(0, 0, 0) },
                    new VertexPositionNormalTexture { Position = new Vector3(1, 0, 0) },
                    new VertexPositionNormalTexture { Position = new Vector3(0, 1, 0) },
                ],
            };
            var batches = new List<TextureBatchData>(retainedMasks.Length);
            for (int i = 0; i < retainedMasks.Length; i++)
            {
                batches.Add(new TextureBatchData
                {
                    Key = new TextureKey { SurfaceId = 0x08000BFFu + (uint)i },
                    TextureData = new byte[8 * 8 * 4],
                    Indices = [0, 1, 2],
                    IsTransparent = true,
                    Translucency = AcDream.Core.Meshing.TranslucencyKind.AlphaBlend,
                    RetailSurfaceMask = retainedMasks[i],
                    CullMode = CullMode.Clockwise,
                    IsCellShell = true,
                    SourceSurfaceIndex = i,
                });
            }
            mesh.TextureBatches[(8, 8, TextureFormat.RGBA8)] = batches;
            Assert.NotNull(_meshManager.UploadMeshData(mesh));

            Renderer = new EnvCellRenderer(
                Device,
                _frames,
                _scope,
                _meshManager,
                new WbFrustum(),
                detailSurfaceActive
                    ? new TerrainAtlas.RetailDetailTextureBinding(
                        new GpuTextureSlot(99),
                        Tiling: 2f,
                        SurfaceTextureId: 1,
                        RenderSurfaceId: 2,
                        Width: 4,
                        Height: 4)
                    : default,
                detailSurfaceActive ? DetailOn : DetailOff);
            typeof(EnvCellRenderer)
                .GetField("_activeSnapshot", System.Reflection.BindingFlags.NonPublic
                    | System.Reflection.BindingFlags.Instance)!
                .SetValue(Renderer, new EnvCellVisibilitySnapshot
                {
                    BatchedByCell = new Dictionary<uint, Dictionary<ulong, List<InstanceData>>>
                    {
                        [CellId] = new Dictionary<ulong, List<InstanceData>>
                        {
                            [MeshId] =
                            [
                                new InstanceData
                                {
                                    Transform = Matrix4x4.Identity,
                                    CellId = CellId,
                                },
                            ],
                        },
                    },
                });

            Queue = new RetailAlphaQueue();
            ClipSource = new RetailPViewPassExecutor.EnvCellAlphaDrawSource(
                Renderer.RenderTransparentOrdered,
                EnvCellTransparentRoute.Clip);
            AlphaSource = new RetailPViewPassExecutor.EnvCellAlphaDrawSource(
                Renderer.RenderTransparentOrdered,
                EnvCellTransparentRoute.Alpha);
            ImmediateSink = new ProductionImmediateSink(Renderer);

            _frames.BeginFrame();
            IGpuFrame frame = _frames.CurrentFrame!;
            _pass = frame.BeginPass(
                GpuPassDescription.BackbufferClear(
                    "s4-c2-envcell-production",
                    Vector4.Zero,
                    sampleCount: 1));
            _publication = _scope.Publish(_pass);
            Renderer.BeginFrame(frameSlot: 0);
            Device.Clear();
        }

        public RecordingGpuDevice Device { get; }

        public EnvCellRenderer Renderer { get; }

        public RetailAlphaQueue Queue { get; }

        public RetailPViewPassExecutor.EnvCellAlphaDrawSource ClipSource { get; }

        public RetailPViewPassExecutor.EnvCellAlphaDrawSource AlphaSource { get; }

        public ProductionImmediateSink ImmediateSink { get; }

        private static bool DetailOn() => true;

        private static bool DetailOff() => false;

        public void Dispose()
        {
            _publication.Dispose();
            _pass.Dispose();
            Renderer.Dispose();
            _meshManager.Dispose();
            Device.Dispose();
        }
    }

    private sealed class ProductionImmediateSink(EnvCellRenderer renderer) :
        IEnvCellImmediateDrawSink
    {
        public int DrawCount { get; private set; }

        public bool LastDetailSurfaceActive { get; private set; }

        public void DrawImmediate(
            uint cellId,
            EnvCellTransparentRoute route,
            bool detailSurfaceActive)
        {
            DrawCount++;
            LastDetailSurfaceActive = detailSurfaceActive;
            renderer.RenderTransparentOrdered([cellId], route, detailSurfaceActive);
        }
    }

    private sealed class NullPreparedAssetSource : IPreparedAssetSource
    {
        public PreparedAssetSourceStats Stats => default;

        public CacheStats DecodedTextureCacheStats => default;

        public PreparedAssetPresence Probe(
            AcDream.Content.Pak.PakAssetType type,
            uint sourceFileId) =>
            PreparedAssetPresence.Missing;

        public PreparedAssetReadResult Read(
            in PreparedAssetRequest request,
            CancellationToken cancellationToken = default) =>
            PreparedAssetReadResult.Missing;

        public void Dispose()
        {
        }
    }

    private sealed class RecordingSource(string name, List<string> log) : IRetailAlphaDrawSource
    {
        private int[] _prepared = [];

        public void PrepareAlphaDraws(ReadOnlySpan<int> tokens) => _prepared = tokens.ToArray();

        public void DrawPreparedAlphaBatch(int firstPreparedDraw, int drawCount)
        {
            for (int i = 0; i < drawCount; i++)
                log.Add($"{name}:{_prepared[firstPreparedDraw + i]}");
        }

        public void ResetAlphaSubmissions()
        {
        }
    }

    private sealed class NoAllocRouteSink
    {
        public void Render(
            IReadOnlyList<uint> cells,
            EnvCellTransparentRoute route,
            bool detailSurfaceActive)
        {
        }

        public void DrawImmediate(
            uint cellId,
            EnvCellTransparentRoute route,
            bool detailSurfaceActive)
        {
        }
    }
}