using System;
using System.IO;
using DatReaderWriter;
using DatReaderWriter.DBObjs;
using DatReaderWriter.Options;
using Xunit;
using Xunit.Abstractions;
using Env = System.Environment;

namespace AcDream.Core.Tests.Physics;

/// <summary>
/// #137 corridor-seam inspection (2026-07-05, Facility Hub). Live probe
/// evidence (launch-175-verify2.log:42858): crossing corridor cells
/// 0x8A02016E → 0x8A02017A at world x≈85.25 records a wall hit with normal
/// (−1,0,0) — pointing straight back against the movement — after which the
/// stale sliding normal wedges all forward motion (ok=False hit=no, offset
/// projected to zero). Question this dump answers: does cell 0x8A02017A's
/// PHYSICS polygon set contain a portal-spanning polygon at its entry plane
/// (normal ≈ ±X at the portal's local X) — i.e., are portal-sealing polys in
/// our collision set where retail filters them?
/// </summary>
public class Issue137CorridorSeamInspectionTests
{
    private readonly ITestOutputHelper _out;
    public Issue137CorridorSeamInspectionTests(ITestOutputHelper output) => _out = output;

    [Theory]
    [InlineData(0x8A02016Eu)]
    [InlineData(0x8A02017Au)]
    public void CorridorCell_PhysicsPolysAndPortals_DatInspection(uint envCellId)
    {
        var datDir = Env.GetEnvironmentVariable("ACDREAM_DAT_DIR")
            ?? Path.Combine(Env.GetFolderPath(Env.SpecialFolder.UserProfile),
                            "Documents", "Asheron's Call");
        if (!Directory.Exists(datDir))
        {
            _out.WriteLine($"SKIP: dat directory not found at {datDir}");
            return;
        }

        using var dats = new DatCollection(datDir, DatAccessType.Read);

        var envCell = dats.Get<EnvCell>(envCellId);
        Assert.NotNull(envCell);
        _out.WriteLine($"=== EnvCell 0x{envCellId:X8} ===");
        _out.WriteLine($"  pos=({envCell!.Position.Origin.X:F2},{envCell.Position.Origin.Y:F2},{envCell.Position.Origin.Z:F2}) " +
                       $"rot=({envCell.Position.Orientation.X:F3},{envCell.Position.Orientation.Y:F3},{envCell.Position.Orientation.Z:F3},{envCell.Position.Orientation.W:F3})");
        _out.WriteLine($"  EnvironmentId=0x{envCell.EnvironmentId:X4} CellStructure={envCell.CellStructure}");
        _out.WriteLine($"  CellPortals={envCell.CellPortals.Count}");
        foreach (var p in envCell.CellPortals)
            _out.WriteLine($"    portal poly={p.PolygonId} other=0x{p.OtherCellId:X4} flags={p.Flags}");

        var environment = dats.Get<DatReaderWriter.DBObjs.Environment>(0x0D000000u | envCell.EnvironmentId);
        Assert.NotNull(environment);
        Assert.True(environment!.Cells.TryGetValue(envCell.CellStructure, out var cs));

        _out.WriteLine($"  PhysicsPolygons={cs!.PhysicsPolygons.Count} (portal-relevant normals below)");
        foreach (var (id, poly) in cs.PhysicsPolygons)
        {
            // Compute the face normal from the vertex fan (same math as
            // PhysicsDataCache.ResolvePolygons).
            var verts = poly.VertexIds;
            if (verts.Count < 3) continue;
            if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[0], out var v0)) continue;
            if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[1], out var v1)) continue;
            if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[2], out var v2)) continue;
            var n = System.Numerics.Vector3.Normalize(System.Numerics.Vector3.Cross(
                v1.Origin - v0.Origin, v2.Origin - v0.Origin));

            // Only print near-horizontal-normal polys (walls) — the seam wall
            // candidates; floors/ceilings are noise here.
            if (MathF.Abs(n.Z) > 0.3f) continue;
            _out.WriteLine($"    poly {id}: n=({n.X:F2},{n.Y:F2},{n.Z:F2}) v0=({v0.Origin.X:F2},{v0.Origin.Y:F2},{v0.Origin.Z:F2}) verts={verts.Count} sides={poly.SidesType} stip={poly.Stippling}");
        }

        // The portal polygons live in the VISUAL polygon set — print their
        // ids so overlap with the physics set (same id space?) is visible.
        _out.WriteLine($"  VisualPolygons={cs.Polygons.Count}");
        foreach (var p in envCell.CellPortals)
        {
            if (cs.Polygons.TryGetValue((ushort)p.PolygonId, out var vp))
            {
                _out.WriteLine($"    portal-poly {p.PolygonId} IS in the visual set (verts={vp.VertexIds.Count})");
                bool inPhysics = cs.PhysicsPolygons.ContainsKey((ushort)p.PolygonId);
                _out.WriteLine($"    portal-poly {p.PolygonId} in PHYSICS set: {inPhysics}");
            }
        }
    }

    /// <summary>
    /// Mechanism-1 follow-up (2026-07-06): being in the CellStruct's
    /// <c>PhysicsPolygons</c> TABLE does not mean the physics BSP ever tests a
    /// polygon — retail's <c>BSPLEAF::sphere_intersects_poly</c> (0x0053d580)
    /// iterates the LEAF's <c>in_polys</c> index list (leaf construction
    /// 0x0053d4a0: <c>in_polys[i] = &amp;pack_poly[index]</c>), and our
    /// BSPQuery walks the dat's PhysicsBSP leaves the same way. This dump
    /// answers: do the physics-BSP LEAVES of the corridor cells reference the
    /// portal polygons? If yes, retail's own BSP query would test them too
    /// (→ the passable mechanism must be transit/approach-side — the cdb
    /// question). If no, our collision is testing polys retail never reaches
    /// (→ a desk-fixable acdream divergence).
    /// </summary>
    [Theory]
    [InlineData(0x8A02016Eu)]
    [InlineData(0x8A02017Au)]
    public void CorridorCell_PhysicsBspLeafMembership_OfPortalPolys(uint envCellId)
    {
        var datDir = Env.GetEnvironmentVariable("ACDREAM_DAT_DIR")
            ?? Path.Combine(Env.GetFolderPath(Env.SpecialFolder.UserProfile),
                            "Documents", "Asheron's Call");
        if (!Directory.Exists(datDir))
        {
            _out.WriteLine($"SKIP: dat directory not found at {datDir}");
            return;
        }

        using var dats = new DatCollection(datDir, DatAccessType.Read);

        var envCell = dats.Get<EnvCell>(envCellId);
        Assert.NotNull(envCell);
        var environment = dats.Get<DatReaderWriter.DBObjs.Environment>(0x0D000000u | envCell!.EnvironmentId);
        Assert.NotNull(environment);
        Assert.True(environment!.Cells.TryGetValue(envCell.CellStructure, out var cs));

        var portalPolyIds = new System.Collections.Generic.HashSet<ushort>();
        foreach (var p in envCell.CellPortals)
            portalPolyIds.Add((ushort)p.PolygonId);

        _out.WriteLine($"=== EnvCell 0x{envCellId:X8} — physics BSP leaf membership ===");
        _out.WriteLine($"  Env=0x{envCell.EnvironmentId:X4} struct={envCell.CellStructure} " +
                       $"portalPolyIds=[{string.Join(",", portalPolyIds)}] " +
                       $"physicsTable=[{string.Join(",", cs!.PhysicsPolygons.Keys)}]");

        var root = cs.PhysicsBSP?.Root;
        Assert.NotNull(root);

        int leafCount = 0;
        var leafPolyIds = new System.Collections.Generic.HashSet<ushort>();
        var portalPolyLeafHits = new System.Collections.Generic.List<string>();
        var stack = new System.Collections.Generic.Stack<(DatReaderWriter.Types.PhysicsBSPNode Node, string Path)>();
        stack.Push((root!, "R"));
        while (stack.Count > 0)
        {
            var (n, path) = stack.Pop();
            if (n.Polygons is { Count: > 0 })
            {
                leafCount++;
                foreach (var pid in n.Polygons)
                {
                    leafPolyIds.Add(pid);
                    if (portalPolyIds.Contains(pid))
                        portalPolyLeafHits.Add($"poly {pid} in leaf@{path} (type={n.Type}, polys=[{string.Join(",", n.Polygons)}])");
                }
            }
            if (n.PosNode is not null) stack.Push((n.PosNode, path + "+"));
            if (n.NegNode is not null) stack.Push((n.NegNode, path + "-"));
        }

        _out.WriteLine($"  BSP leaves-with-polys={leafCount} distinctLeafPolyIds=[{string.Join(",", leafPolyIds)}]");
        var tableNotInLeaves = new System.Collections.Generic.List<ushort>();
        foreach (var pid in cs.PhysicsPolygons.Keys)
            if (!leafPolyIds.Contains(pid))
                tableNotInLeaves.Add(pid);
        _out.WriteLine($"  physics-table polys NOT referenced by any BSP leaf: [{string.Join(",", tableNotInLeaves)}]");

        if (portalPolyLeafHits.Count == 0)
        {
            _out.WriteLine("  >>> NO portal polygon is referenced by any physics-BSP leaf — " +
                           "retail's sphere_intersects_poly never tests them from this cell's BSP.");
        }
        else
        {
            foreach (var hit in portalPolyLeafHits)
                _out.WriteLine($"  >>> PORTAL POLY IN PHYSICS LEAF: {hit}");
        }
    }

    /// <summary>
    /// Mechanism-1 re-characterization (2026-07-06): the live hit normal
    /// (−1.00, 0.03, −0.03) at world (85.253, −39.776, −5.992) matches NO
    /// physics polygon of either corridor cell — 0x8A02016E (identity
    /// rotation) and 0x8A02017A (180° Z) both have only ±Y-normal wall polys,
    /// and the PortalSide portals to 0x011E (polys 1/3/5) are ±Y planes
    /// 1.4 m north of the player's track, perpendicular to the +X run — the
    /// pos_hits_sphere directional cull rejects them for this movement. This
    /// sweep hunts the ACTUAL culprit: every physics poly of the seam cell +
    /// all portal-adjacent neighbors, world-transformed, scored against the
    /// hit point + normal.
    /// </summary>
    [Fact]
    public void CorridorSeam_FindPolygonMatchingLiveHit()
    {
        var datDir = Env.GetEnvironmentVariable("ACDREAM_DAT_DIR")
            ?? Path.Combine(Env.GetFolderPath(Env.SpecialFolder.UserProfile),
                            "Documents", "Asheron's Call");
        if (!Directory.Exists(datDir))
        {
            _out.WriteLine($"SKIP: dat directory not found at {datDir}");
            return;
        }

        using var dats = new DatCollection(datDir, DatAccessType.Read);

        // Live evidence (launch-175-verify2.log:42858).
        var hitPoint  = new System.Numerics.Vector3(85.253f, -39.776f, -5.992f);
        var hitNormal = new System.Numerics.Vector3(-1.00f, 0.03f, -0.03f);
        hitNormal = System.Numerics.Vector3.Normalize(hitNormal);
        const float sphereRadius = 0.48f;

        // Seam cells + every portal-adjacent neighbor of both.
        var cellIds = new System.Collections.Generic.HashSet<uint>
        {
            0x8A02016Eu, 0x8A02017Au,
        };
        foreach (var seed in new[] { 0x8A02016Eu, 0x8A02017Au })
        {
            var seedCell = dats.Get<EnvCell>(seed);
            if (seedCell is null) continue;
            foreach (var p in seedCell.CellPortals)
                cellIds.Add(0x8A020000u | p.OtherCellId);
        }

        foreach (var cellId in cellIds)
        {
            var envCell = dats.Get<EnvCell>(cellId);
            if (envCell is null) { _out.WriteLine($"cell 0x{cellId:X8}: NOT FOUND"); continue; }
            var environment = dats.Get<DatReaderWriter.DBObjs.Environment>(0x0D000000u | envCell.EnvironmentId);
            if (environment is null || !environment.Cells.TryGetValue(envCell.CellStructure, out var cs))
                continue;

            var rot = new System.Numerics.Quaternion(
                envCell.Position.Orientation.X, envCell.Position.Orientation.Y,
                envCell.Position.Orientation.Z, envCell.Position.Orientation.W);
            var world = System.Numerics.Matrix4x4.CreateFromQuaternion(rot)
                      * System.Numerics.Matrix4x4.CreateTranslation(
                            envCell.Position.Origin.X, envCell.Position.Origin.Y, envCell.Position.Origin.Z);

            var portalPolyIds = new System.Collections.Generic.HashSet<ushort>();
            foreach (var p in envCell.CellPortals) portalPolyIds.Add((ushort)p.PolygonId);

            foreach (var (id, poly) in cs!.PhysicsPolygons)
            {
                var verts = poly.VertexIds;
                if (verts.Count < 3) continue;
                if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[0], out var v0)) continue;
                if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[1], out var v1)) continue;
                if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[2], out var v2)) continue;

                var w0 = System.Numerics.Vector3.Transform(v0.Origin, world);
                var w1 = System.Numerics.Vector3.Transform(v1.Origin, world);
                var w2 = System.Numerics.Vector3.Transform(v2.Origin, world);
                var n  = System.Numerics.Vector3.Normalize(
                    System.Numerics.Vector3.Cross(w1 - w0, w2 - w0));

                float align = System.Numerics.Vector3.Dot(n, hitNormal);
                if (align < 0.95f) continue;   // within ~18° of the recorded normal

                // Plane distance from the hit point.
                float d = -System.Numerics.Vector3.Dot(n, w0);
                float dist = System.Numerics.Vector3.Dot(n, hitPoint) + d;
                if (MathF.Abs(dist) > sphereRadius + 0.1f) continue;

                // Rough proximity: hit point near the polygon's vertex span.
                float minX = MathF.Min(w0.X, MathF.Min(w1.X, w2.X)) - 1f;
                float maxX = MathF.Max(w0.X, MathF.Max(w1.X, w2.X)) + 1f;
                float minY = MathF.Min(w0.Y, MathF.Min(w1.Y, w2.Y)) - 1f;
                float maxY = MathF.Max(w0.Y, MathF.Max(w1.Y, w2.Y)) + 1f;
                if (hitPoint.X < minX || hitPoint.X > maxX ||
                    hitPoint.Y < minY || hitPoint.Y > maxY) continue;

                _out.WriteLine(
                    $">>> CANDIDATE cell=0x{cellId:X8} poly={id} " +
                    $"worldN=({n.X:F3},{n.Y:F3},{n.Z:F3}) align={align:F3} planeDist={dist:F3} " +
                    $"isPortalPoly={portalPolyIds.Contains(id)} " +
                    $"w0=({w0.X:F2},{w0.Y:F2},{w0.Z:F2}) w1=({w1.X:F2},{w1.Y:F2},{w1.Z:F2}) w2=({w2.X:F2},{w2.Y:F2},{w2.Z:F2}) " +
                    $"verts={verts.Count} sides={poly.SidesType} stip={poly.Stippling}");
            }
        }
        _out.WriteLine("(sweep complete)");
    }

    /// <summary>
    /// Entry-poly hunt: the synthetic reversed-movement collision normal is
    /// produced by slide_sphere's opposing-normals branch, which needs an
    /// INPUT collision normal anti-parallel to the grounded contact plane —
    /// i.e., a DOWNWARD-facing polygon (lintel / arch underside). Those were
    /// filtered out of the wall dump (|n.Z| &gt; 0.3). Sweep both corridor
    /// cells for downward polys near the seam column and print where their
    /// planes sit relative to the player's head sphere.
    /// </summary>
    [Fact]
    public void CorridorSeam_DownwardPolysNearSeam()
    {
        var datDir = Env.GetEnvironmentVariable("ACDREAM_DAT_DIR")
            ?? Path.Combine(Env.GetFolderPath(Env.SpecialFolder.UserProfile),
                            "Documents", "Asheron's Call");
        if (!Directory.Exists(datDir))
        {
            _out.WriteLine($"SKIP: dat directory not found at {datDir}");
            return;
        }

        using var dats = new DatCollection(datDir, DatAccessType.Read);

        foreach (var cellId in new[] { 0x8A02016Eu, 0x8A02017Au })
        {
            var envCell = dats.Get<EnvCell>(cellId);
            Assert.NotNull(envCell);
            var environment = dats.Get<DatReaderWriter.DBObjs.Environment>(0x0D000000u | envCell!.EnvironmentId);
            Assert.NotNull(environment);
            Assert.True(environment!.Cells.TryGetValue(envCell.CellStructure, out var cs));

            var rot = new System.Numerics.Quaternion(
                envCell.Position.Orientation.X, envCell.Position.Orientation.Y,
                envCell.Position.Orientation.Z, envCell.Position.Orientation.W);
            var world = System.Numerics.Matrix4x4.CreateFromQuaternion(rot)
                      * System.Numerics.Matrix4x4.CreateTranslation(
                            envCell.Position.Origin.X, envCell.Position.Origin.Y, envCell.Position.Origin.Z);

            _out.WriteLine($"=== 0x{cellId:X8} downward physics polys (n.Z < -0.3) ===");
            foreach (var (id, poly) in cs!.PhysicsPolygons)
            {
                var verts = poly.VertexIds;
                if (verts.Count < 3) continue;
                if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[0], out var v0)) continue;
                if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[1], out var v1)) continue;
                if (!cs.VertexArray.Vertices.TryGetValue((ushort)verts[2], out var v2)) continue;

                var w0 = System.Numerics.Vector3.Transform(v0.Origin, world);
                var w1 = System.Numerics.Vector3.Transform(v1.Origin, world);
                var w2 = System.Numerics.Vector3.Transform(v2.Origin, world);
                var n  = System.Numerics.Vector3.Normalize(
                    System.Numerics.Vector3.Cross(w1 - w0, w2 - w0));
                if (n.Z > -0.3f) continue;

                // Only near the seam column the player crossed.
                float minX = MathF.Min(w0.X, MathF.Min(w1.X, w2.X));
                float maxX = MathF.Max(w0.X, MathF.Max(w1.X, w2.X));
                if (maxX < 83.5f || minX > 87.0f) continue;

                var allW = new System.Collections.Generic.List<System.Numerics.Vector3>();
                foreach (var vid in verts)
                    if (cs.VertexArray.Vertices.TryGetValue((ushort)vid, out var vv))
                        allW.Add(System.Numerics.Vector3.Transform(vv.Origin, world));
                float minZ = float.MaxValue, maxZ = float.MinValue, minY = float.MaxValue, maxY = float.MinValue;
                foreach (var w in allW)
                {
                    minZ = MathF.Min(minZ, w.Z); maxZ = MathF.Max(maxZ, w.Z);
                    minY = MathF.Min(minY, w.Y); maxY = MathF.Max(maxY, w.Y);
                }

                _out.WriteLine(
                    $"  poly {id}: worldN=({n.X:F2},{n.Y:F2},{n.Z:F2}) x=[{minX:F2},{maxX:F2}] " +
                    $"y=[{minY:F2},{maxY:F2}] z=[{minZ:F2},{maxZ:F2}] verts={verts.Count} " +
                    $"sides={poly.SidesType} stip={poly.Stippling}");
            }
        }
        _out.WriteLine("(downward sweep complete)");
    }
}