using System.Numerics;
using AcDream.App.Rendering.Gpu;
using AcDream.App.Rendering.Walk;
using DatReaderWriter;

namespace AcDream.App.Tests.Rendering.Walk;

/// <summary>
/// S4-c1 fix round 1, F3: the automated depth-event transcript gate.
/// Replays each OH alpha/depth capture's frame 2 through the SAME ported
/// walk (<see cref="RetailFrameWalk"/> + <see cref="WalkFrameDriver"/>,
/// <see cref="WalkTraceReplayContext"/> + <see cref="WalkLandscapeDatBuilder"/>
/// — the identical replay harness <see cref="WalkTraceConformanceTests"/>
/// already uses) with a RECORDING sink/leaf pair that reproduces retail's
/// own PM (mode, counterBefore) and PC (ov, counter, forceClear) sequences,
/// then compares them against <see cref="WalkAlphaDepthTrace"/>'s parse of
/// the real capture, exactly (pointers ignored).
///
/// <para><b>Why two observation points, not one.</b> Retail's PM line fires
/// at <c>DrawPortalPolyInternal</c>'s function ENTRY — before the four-plane
/// boundary guard (S4-c1 F1) has run — so a PM line is emitted for every
/// ATTEMPT, guard-rejected or not. A building punch's guard decision runs
/// INSIDE <see cref="WalkFrameDriver.OnPunchGeometry"/> (a Collect-time
/// hook): a rejected punch never reaches <see cref="IWalkFrameLeafRenderer.DrawPunchFan"/>
/// at all, so <see cref="AlphaDepthCollectSink"/> intercepts
/// <c>OnPunchGeometry</c> ITSELF, at Collect time, before the guard runs —
/// reading <see cref="WalkFrameDriver.PortalsDrawnCount"/> there gives the
/// PRE-reset value retail's own punches observe (Collect completes entirely
/// before Replay starts, so reading the counter at Replay time would already
/// see the root's own post-reset value — the wrong number, confirmed against
/// holtburg-doorway-still's own counterBefore=0002 punches immediately
/// followed by counterBefore=0000/0001 seals in the SAME turn). Exit seals
/// have no such Collect-time per-portal hook at all (<see
/// cref="IWalkFrameLeafRenderer.DrawExitSeals"/> takes no cell/portal
/// argument — <c>RetailPViewPassExecutor.DrawPortalDepthWrite</c> owns the
/// real per-portal loop entirely at Replay time), so <see cref="AlphaDepthLeaf"/>
/// reproduces that SAME loop (S4-c1 F1's guard, F2's count-before-clip order)
/// directly over the walk's own <see cref="WalkFrameDriver.InteriorFloodCells"/>
/// / <see cref="WalkCell.Portals"/> / <see cref="WalkCell.PortalPolygons"/> —
/// the identical LOCAL portal-polygon data the production seal path reads,
/// at Replay time, which is also where retail's own exit-seal loop runs
/// (established: punches always precede the single per-root ExitSeals
/// Collect-time event, so simple list concatenation reproduces the exact
/// interleaved PM order without needing a shared Collect/Replay timeline).
/// </para>
///
/// <para><b>Why two Collect+Replay passes per pose, not one.</b> Retail's
/// <c>portalsDrawnCount</c> is a PERSISTENT global, unaffected by any reset
/// between captured frames whose interior turn never fires (see
/// terrace-edge below). holtburg-doorway-still and foundry-deep both show a
/// STEADY-STATE cycle (the same N seals accepted every captured frame,
/// carrying the SAME counter value into the next frame's own PC read) —
/// reachable from a cold <c>PortalsDrawnCount=0</c> start after exactly one
/// full "priming" pass, so this gate discards a first Collect+Replay pass's
/// own output and compares only the second.</para>
/// </summary>
public sealed partial class WalkTraceConformanceTests
{
    /// <summary>Collect-time <see cref="IWalkEventSink"/> decorator: forwards
    /// every hook to the real <see cref="WalkFrameDriver"/> unchanged (so its
    /// own event collection stays complete and correct), while separately
    /// recording the two families this gate needs — see this file's own
    /// class doc comment for why punches must be captured HERE rather than
    /// at Replay.</summary>
    private sealed class AlphaDepthCollectSink : IWalkEventSink
    {
        private readonly WalkFrameDriver _driver;
        private readonly IWalkEventSink _inner;

        public AlphaDepthCollectSink(WalkFrameDriver driver)
        {
            _driver = driver;
            _inner = driver;
        }

        public readonly List<(int Mode, int CounterBefore)> Punches = new();
        public readonly List<(int Ov, int Counter, int ForceClear)> PcEvents = new();

        public void Emit(in WalkEvent walkEvent)
        {
            // PView::DrawCells @0x005a4840's own PC print fires at function
            // ENTRY for every call — the root's own turn AND every building
            // look-in's re-entrant call alike (oh1-depth-lifecycle.md: the
            // breakpoint doesn't distinguish). WalkEventKind.DrawCells's
            // Emit call is the walk's own "this DrawCells call happened"
            // signal at that SAME entry-order point (its own doc comment:
            // "sits at breakpoint-ENTRY order"); forceClear (oh1: no write
            // site found anywhere in the binary) is always 0.
            if (walkEvent.Kind == WalkEventKind.DrawCells)
                PcEvents.Add((walkEvent.OutsideViewCount, _driver.PortalsDrawnCount, 0));
            _inner.Emit(walkEvent);
        }

        public void OnLandscapeViews(WalkPortalView activeViews) =>
            _inner.OnLandscapeViews(activeViews);

        public void OnLandCellTurn(uint landblockId, int sideCellCount, int cellIndex) =>
            _inner.OnLandCellTurn(landblockId, sideCellCount, cellIndex);

        public void OnSortCellTurn(uint landblockId, int sideCellCount, int cellIndex) =>
            _inner.OnSortCellTurn(landblockId, sideCellCount, cellIndex);

        public void OnLandscapeCellTurn(uint cellId) =>
            _inner.OnLandscapeCellTurn(cellId);

        public void OnLandscapeCellTurn(uint landblockId, int sideCellCount, int cellIndex) =>
            _inner.OnLandscapeCellTurn(landblockId, sideCellCount, cellIndex);

        public void OnBuildingTurn(WalkBuilding building) =>
            _inner.OnBuildingTurn(building);

        public void OnBuildingShellTurn(WalkBuilding building) =>
            _inner.OnBuildingShellTurn(building);

        public void OnPunchGeometry(
            WalkBuilding building, WalkPolygon polygon, int activeViewIndex)
        {
            // Far-Z punches never touch portalsDrawnCount (R2); this reads
            // it purely as a snapshot for the transcript, BEFORE the SAME
            // interior root's own OnInteriorFloodDrawTurn reset — see class
            // doc comment.
            Punches.Add((1, _driver.PortalsDrawnCount));
            _inner.OnPunchGeometry(building, polygon, activeViewIndex);
        }

        public void OnInteriorFloodDrawTurn(IReadOnlyList<uint> cells, int outsideViewCount) =>
            _inner.OnInteriorFloodDrawTurn(cells, outsideViewCount);

        public void OnWeatherTurn(uint viewerCellId) =>
            _inner.OnWeatherTurn(viewerCellId);
    }

    /// <summary>Replay-time <see cref="IWalkFrameLeafRenderer"/>: every
    /// member besides <see cref="DrawExitSeals"/> is a plain no-op (this
    /// gate cares only about the depth/count mechanism, not mesh content).
    /// <see cref="DrawExitSeals"/> reproduces
    /// <c>RetailPViewPassExecutor.DrawPortalDepthWrite</c>'s real per-portal
    /// loop — S4-c1 F1's guard, F2's count-before-clip order — directly over
    /// the walk's own flood/cell data (no fake GPU clip needed: F2
    /// established the count happens unconditionally once the guard
    /// passes).</summary>
    private sealed class AlphaDepthLeaf : IWalkFrameLeafRenderer
    {
        private readonly Dictionary<uint, WalkCell> _cells;

        public AlphaDepthLeaf(Dictionary<uint, WalkCell> cells) => _cells = cells;

        /// <summary>Set once, immediately after construction — the leaf and
        /// its owning <see cref="WalkFrameDriver"/> are mutually referential
        /// (the driver's constructor requires the leaf), so this cannot be a
        /// constructor parameter.</summary>
        public WalkFrameDriver Driver { get; set; } = null!;

        public readonly List<(int Mode, int CounterBefore)> Seals = new();

        public void DrawSky() { }
        public void DrawLandCellBatch(
            IReadOnlyList<(uint LandblockId, int SideCellCount, int CellIndex)> cells) { }
        public bool HasRenderableEmittersInCell(uint cellId) => false;
        public void DrawCellShell(uint cellId) { }
        public void DrawStaticParticles(uint cellId) { }
        public void DrawCellParticles(uint cellId) { }
        public void ClearInteriorDepth() { }
        public void FlushLandscape() { }
        public void DrawPunchFan(WalkPolygon worldPolygon, int activeViewIndex) { }
        public void AlphaBarrier() { }

        public int DrawExitSeals()
        {
            int accepted = 0;
            List<uint> flood = Driver.InteriorFloodCells;
            // Reverse order — the SAME direction DrawWalkExitPortalMasks
            // walks driver.InteriorFloodCells in production
            // (RetailPViewRenderer.cs).
            for (int i = flood.Count - 1; i >= 0; i--)
            {
                if (!_cells.TryGetValue(flood[i], out WalkCell? cell))
                    continue;
                int sliceCount = Driver.InteriorFloodViewSliceCountAt(i);
                for (int slice = 0; slice < sliceCount; slice++)
                {
                    for (int p = 0; p < cell.Portals.Length; p++)
                    {
                        WalkCellPortal portal = cell.Portals[p];
                        // Walk-side exit sentinel is 32-bit 0xFFFFFFFF
                        // (WalkCellPortal's own doc comment) — the render-
                        // side CellPortalInfo's 16-bit 0xFFFF is a DIFFERENT
                        // representation of the same fact.
                        if (portal.OtherCellId != 0xFFFFFFFFu)
                            continue;
                        if ((uint)portal.PolygonIndex >= (uint)cell.PortalPolygons.Length)
                            continue;
                        WalkPolygon poly = cell.PortalPolygons[portal.PolygonIndex];

                        // F2: count happens BEFORE clip (unconditionally,
                        // once the guard passes) — counterBefore is the
                        // running total BEFORE this specific portal's own
                        // decision.
                        Seals.Add((0, Driver.PortalsDrawnCount + accepted));
                        if (!WalkVisibilityMath.IsRejectedByPortalPolygonBoundaryGuard(
                                poly.Vertices))
                        {
                            accepted++;
                        }
                    }
                }
            }
            return accepted;
        }
    }

    /// <summary>Minimal <see cref="IWalkFrameWorldData"/>: this gate never
    /// inspects mesh content, only the depth/count event sequence, so every
    /// query returns the shared empty record.</summary>
    private sealed class EmptyAlphaDepthWorldData : IWalkFrameWorldData
    {
        public WalkFrameStaticRecords GetCellStatics(uint cellId) => WalkFrameStaticRecords.Empty;
        public WalkFrameStaticRecords GetCellDynamics(uint cellId) => WalkFrameStaticRecords.Empty;
        public WalkFrameStaticRecords GetOutdoorStatics(uint cellId) => WalkFrameStaticRecords.Empty;
        public WalkFrameStaticRecords GetOutdoorDynamics(uint cellId) => WalkFrameStaticRecords.Empty;
        public WalkFrameStaticRecords GetBuildingShellStatics(WalkBuilding building) =>
            WalkFrameStaticRecords.Empty;
        public Matrix4x4 GetBuildingWorldTransform(WalkBuilding building) => Matrix4x4.Identity;
    }

    /// <summary>Runs the two-pass replay (see class doc comment for why two)
    /// and asserts the SECOND pass's PM/PC sequences against
    /// <paramref name="fixtureName"/>'s captured frame 2
    /// (<see cref="WalkAlphaDepthTrace"/>'s <c>frames[1]</c>, matching every
    /// other OH-capture row's own frame-2 convention in this file).</summary>
    private void RunAlphaDepthTranscriptGate(string fixtureName)
    {
        IReadOnlyList<WalkOracleFrame> poseFrames = WalkOracleTrace.Load(OhCaptureRoot, fixtureName);
        Assert.NotEmpty(poseFrames);
        Assert.True(poseFrames.Count > 1, $"{fixtureName}: need a captured frame 2.");
        WalkOracleFrame poseFrame = poseFrames[1];
        Assert.NotNull(poseFrame.Pose);
        WalkOraclePose pose = poseFrame.Pose!;

        IReadOnlyList<WalkAlphaDepthFrame> depthFrames = WalkAlphaDepthTrace.Load(OhCaptureRoot, fixtureName);
        Assert.True(depthFrames.Count > 1, $"{fixtureName}: need a captured frame 2's PM/PC content.");
        WalkAlphaDepthFrame expected = depthFrames[1];

        using DatCollection dats = OpenDats();
        WalkLandscapeDatBuilder.BuiltWorld world =
            WalkLandscapeDatBuilder.Build(dats, pose.CellId, pose.Origin);
        var ctx = new WalkTraceReplayContext(pose, world.Cells) { Buildings = world.Buildings };
        WalkCell? camera = (pose.CellId & 0xFFFFu) >= 0x100
            ? Assert.Contains(pose.CellId, world.Cells)
            : null;

        using var fx = new WalkFrameDriverTests.DispatcherFixture();
        var worldData = new EmptyAlphaDepthWorldData();
        var leaf = new AlphaDepthLeaf(world.Cells);
        var driver = new WalkFrameDriver(fx.Dispatcher, leaf, worldData);
        leaf.Driver = driver;
        var sink = new AlphaDepthCollectSink(driver);
        var walk = new RetailFrameWalk();

        void RunOnePass()
        {
            using (WalkFrameDriverTests.DrawScope draw = fx.BeginDraw())
            {
                driver.BeginFrame(ctx, Matrix4x4.Identity, pose.Origin);
                walk.WalkFrame(pose.CellId, camera, world.Landscape, ctx, sink);
                driver.EndFrame();
                driver.Replay(draw.Frame, draw.Pass);
            }
            // DrawScope.Dispose ends only the pass/publication — the frame
            // itself (RecordingGpuDevice's "one open frame" invariant) is
            // ended separately, same order WalkOutsideViewReassemblyTests'
            // own multi-draw loop uses.
            fx.FrameLifetime.EndFrame();
        }

        // Priming pass: reaches the steady state a real running session
        // would already be in by the time retail's capture began (see class
        // doc comment) — its own recorded output is discarded.
        RunOnePass();
        sink.Punches.Clear();
        sink.PcEvents.Clear();
        leaf.Seals.Clear();

        // Comparison pass.
        RunOnePass();

        var actualPm = new List<(int Mode, int CounterBefore)>(sink.Punches);
        actualPm.AddRange(leaf.Seals);

        Assert.Equal(expected.PmEvents, actualPm);
        Assert.Equal(expected.PcEvents, sink.PcEvents);
    }

    [Fact]
    public void AlphaDepthTranscript_CathedralArrival_MatchesRetailFrame2()
        => RunAlphaDepthTranscriptGate("cathedral-arrival.alphadepth");

    [Fact]
    public void AlphaDepthTranscript_FoundryDeep_MatchesRetailFrame2()
        => RunAlphaDepthTranscriptGate("foundry-deep.alphadepth");

    [Fact]
    public void AlphaDepthTranscript_HoltburgDoorwayStill_MatchesRetailFrame2()
        => RunAlphaDepthTranscriptGate("holtburg-doorway-still.alphadepth");

    /// <summary>
    /// PINNED KnownFailure (S4-c1 fix round 1, F3): terrace-edge never runs
    /// a qualifying interior turn anywhere in its own capture (every PC line
    /// reads <c>ov=0</c>) — its two building punches' <c>counterBefore=2</c>
    /// is a PERSISTENT session value carried over from BEFORE the capture
    /// even started (the file's own pre-"F 1" content already reads 2; no
    /// mechanism inside the captured frames ever changes it). A fresh two-
    /// pass replay from <c>PortalsDrawnCount=0</c> has no way to derive that
    /// leftover value — there is no seal activity anywhere in this fixture
    /// to prime it — so this pose's own comparison pass reads
    /// <c>counterBefore=0</c> where retail shows 2. This is an initial-
    /// condition gap in the fixture itself, not a guard/count defect: the
    /// SAME replay harness reproduces holtburg-doorway-still's and foundry-
    /// deep's own steady-state counter values exactly from a cold start.
    /// Observed divergence (both PM events, the fixture's only two):
    /// expected <c>[(mode=1, counterBefore=2), (mode=1, counterBefore=2)]</c>,
    /// actual <c>[(mode=1, counterBefore=0), (mode=1, counterBefore=0)]</c>;
    /// the PC sequence (ov=0 both times) matches exactly.
    /// </summary>
    [Fact]
    [Trait("Status", "KnownFailure")]
    public void AlphaDepthTranscript_TerraceEdge_MatchesRetailFrame2()
        => RunAlphaDepthTranscriptGate("terrace-edge.alphadepth");

    /// <summary>See <see cref="AlphaDepthTranscript_TerraceEdge_MatchesRetailFrame2"/>'s
    /// own doc comment — cathedral-leak carries the exact same steady state
    /// (counter pinned at 0, every exit portal degenerate-onto-plane
    /// rejected) as cathedral-arrival, so it is expected to pass; listed
    /// here because the spec's own fixture count (four) undercounts the
    /// five <c>*.alphadepth.log</c> files actually present in
    /// <c>oh-capture/</c> — see this round's commit body.</summary>
    [Fact]
    public void AlphaDepthTranscript_CathedralLeak_MatchesRetailFrame2()
        => RunAlphaDepthTranscriptGate("cathedral-leak.alphadepth");
}