using AcDream.App.Tests.Rendering;
using AcDream.App.Rendering.Walk;
using DatReaderWriter;
using DatReaderWriter.Options;
using System.Numerics;
using System.Text;

namespace AcDream.App.Tests.Rendering.Walk;

/// <summary>
/// FW1 look-in gate microscope: for the street fixture pose, dump every
/// gate input for building a9b4001a (retail punches it) vs a9b4001e
/// (retail does not): raw portal flags, the BSP-emitted polygon's plane,
/// the eye's signed distance and side, and the active-view clip count.
/// Writes the dump to the scratch directory; always passes.
/// </summary>
[Trait("Lane", "InstalledDat")]
public sealed class WalkPortalGateDumpTests
{
    [Fact]
    public void Dump_the_gate_inputs_for_a_punching_and_a_silent_building()
    {
        string? datDir = CornerFloodReplayTests.ResolveDatDir();
        if (datDir is null)
        {
            Assert.Fail("Lane=InstalledDat requires an installed retail DAT directory.");
        }
        IReadOnlyList<WalkOracleFrame> frames =
            WalkOracleTrace.Load("posed/holtburg-street-outdoor");
        WalkOracleFrame frame = frames[1];
        Assert.NotNull(frame.Pose);
        using var dats = new DatCollection(datDir!, DatAccessType.Read);
        WalkLandscapeDatBuilder.BuiltWorld world =
            WalkLandscapeDatBuilder.Build(dats, frame.Pose!.CellId, frame.Pose.Origin);
        var ctx = new WalkTraceReplayContext(frame.Pose, world.Cells)
        {
            Buildings = world.Buildings,
        };
        // Install the outdoor default view as the active clip context.
        var defaultView = new WalkPortalView();
        WalkCopyView.AppendFullViewportQuad(
            defaultView, ctx.Rays, ctx.WorldViewpoint,
            ctx.ViewportWidth, ctx.ViewportHeight);
        ctx.SetActiveView(defaultView, 0);

        var dump = new StringBuilder();
        Span<WalkScreenPoint> clipped = stackalloc WalkScreenPoint[64];
        dump.AppendLine($"pose cell={frame.Pose.CellId:x8} origin={frame.Pose.Origin}");
        foreach (uint id in new[] { 0xA9B4001Au, 0xA9B4001Eu, 0xA9B40022u, 0xA9B40026u })
        {
            WalkBuilding building = world.Buildings.Keys.Single(b => b.PositionCellId == id);
            float dist = ctx.ViewerDistanceTo(building);
            Vector3 eyeInBuilding = ctx.ViewpointInBuilding(building);
            dump.AppendLine(
                $"building {id:x8}: dist={dist:f1} eff={MathF.Max(0f, dist - 100f):f1} "
                + $"eyeLocal={eyeInBuilding} portals={building.Portals.Length}");
            WalkBspNode? bsp = building.SelectDrawingBsp(dist);
            var refs = new List<WalkPortalRef>();
            Collect(bsp, refs);
            dump.AppendLine($"  level BSP portal refs: {refs.Count}");
            foreach (WalkPortalRef portalRef in refs)
            {
                ref WalkBldPortal bp = ref building.Portals[portalRef.PortalIndex];
                float d = Vector3.Dot(portalRef.Polygon.Plane.Normal, eyeInBuilding)
                    + portalRef.Polygon.Plane.D;
                int side = d > WalkVisibilityMath.Epsilon ? 0
                    : d < -WalkVisibilityMath.Epsilon ? 1 : 2;
                int n = ctx.ClipBuildingPolygon(building, portalRef.Polygon, side, clipped);
                dump.AppendLine(
                    $"  ref idx={portalRef.PortalIndex} other={bp.OtherCellId:x8} "
                    + $"rawSide={bp.PortalSide} exact={bp.ExactMatch} "
                    + $"planeD@eye={d:f2} eyeSide={side} clipN={n} "
                    + $"gate(side==rawSide)={(side == bp.PortalSide ? "PASS" : "reject")}");
            }
        }
        string path = Path.Combine(Path.GetTempPath(), "fw1-portal-gate-dump.txt");
        File.WriteAllText(path, dump.ToString());
        Assert.True(true);
    }

    private static void Collect(WalkBspNode? node, List<WalkPortalRef> into)
    {
        if (node is null) return;
        if (node.InPortals is not null) into.AddRange(node.InPortals);
        Collect(node.PosNode, into);
        Collect(node.NegNode, into);
    }
}