using System.Collections.Generic;
using System.Numerics;
using AcDream.Core.Physics;
using DatReaderWriter;
using DatReaderWriter.Options;
using Xunit;
using Xunit.Abstractions;

namespace AcDream.Core.Tests.Conformance;

/// <summary>
/// #112 (2026-06-10): the A9B3 hill cottage has a real containment GAP inside
/// the house (world (184.9, −109.5, 116) / A9B3-local (184.9, 82.5) is in NO
/// interior cell while points ~0.7 m away are inside 0x100/0x103). The
/// 6dbbf95 escape hatch demoted the walker to the outdoor column there,
/// stranding them outdoor-classified deep indoors (no containment-based
/// re-promotion) → the outdoor flood rendered the interior transparent.
/// Retail find_cell_list KEEPS curr_cell when nothing contains the centre
/// (pc:308788-308825). These tests pin the replacement semantics against the
/// real dats.
/// </summary>
public sealed class Issue112MembershipTests
{
    private readonly ITestOutputHelper _out;
    public Issue112MembershipTests(ITestOutputHelper output) => _out = output;

    private const float FootRadius = 0.48f;

    private static PhysicsDataCache LoadLandblockInteriors(DatCollection dats, uint lbPrefix)
    {
        var cache = new PhysicsDataCache();
        for (uint low = 0x0100; low <= 0x01FF; low++)
        {
            try { ConformanceDats.LoadEnvCell(dats, cache, lbPrefix | low); }
            catch { }
        }
        return cache;
    }

    [Fact]
    public void A9B3CottageGap_AtDoorway_StraddlesExitPlane_DemotesRetailFaithfully()
    {
        var datDir = ConformanceDats.ResolveDatDir();
        if (datDir is null) { _out.WriteLine("dats unavailable — skipped"); return; }
        using var dats = new DatCollection(datDir, DatAccessType.Read);
        var cache = LoadLandblockInteriors(dats, 0xA9B30000u);

        // The gap point (A9B3-local frame, footcenter height): contained by NO
        // interior cell (dat-scan fact from the live capture issue111-verify7).
        var gap = new Vector3(184.915f, 82.464f, 116.48f);

        uint picked = CellTransit.FindCellList(cache, gap, FootRadius, 0xA9B30104u);
        _out.WriteLine($"pick(seed 0x104) at gap -> 0x{picked:X8}");

        // RESOLVED 2026-06-10 (#112 rider, live-binary oracle): retail's
        // CEnvCell::find_transit_cells admits outdoor cells IFF a path sphere
        // STRADDLES an exterior portal's plane (|dist| < radius + F_EPSILON;
        // acclient.exe 0052c8e5-0052c9f0). The gap point sits 0.23 m from
        // 0x104's exit-door plane (x=184.684) with foot radius 0.48 — it
        // STRADDLES, so retail admits the outdoor column and demotes here too.
        // This at-doorway demote is RETAIL-FAITHFUL, not a divergence; it
        // self-heals one step inward via doorway re-promotion. The former
        // "DocumentsResidual" framing is closed — see the deep-gap test below
        // for the behavior that DID change with the straddle gate.
        Assert.Equal(0xA9B3003Cu, picked);
    }

    [Fact]
    public void A9B3Cottage_GapBeyondStraddleDistance_KeepsCurrCell_RetailGate()
    {
        var datDir = ConformanceDats.ResolveDatDir();
        if (datDir is null) { _out.WriteLine("dats unavailable — skipped"); return; }
        using var dats = new DatCollection(datDir, DatAccessType.Read);
        var cache = LoadLandblockInteriors(dats, 0xA9B30000u);

        // A no-cell point past the straddle window: 0.66 m beyond 0x104's
        // exit-door plane (x=184.684 + 0.48 + 0.18), still in no interior cell
        // (inside the shell-wall band). Pre-gate, the A6.P5 topology widening
        // let the outdoor column WIN the pick here → outdoor demote deep in a
        // containment gap (#112's transparent-interior shape). Retail keeps
        // curr_cell: no sphere straddles any exterior portal plane, so the
        // outdoor cells never become pick candidates (live-binary verified).
        var deepGap = new Vector3(185.345f, 82.464f, 116.48f);

        uint picked = CellTransit.FindCellList(cache, deepGap, FootRadius, 0xA9B30104u);
        _out.WriteLine($"pick(seed 0x104) at deep gap -> 0x{picked:X8}");
        Assert.Equal(0xA9B30104u, picked);
    }

    [Fact]
    public void FindTransitCellsSphere_ExitPortalStraddleGate_MatchesRetail()
    {
        var datDir = ConformanceDats.ResolveDatDir();
        if (datDir is null) { _out.WriteLine("dats unavailable — skipped"); return; }
        using var dats = new DatCollection(datDir, DatAccessType.Read);
        var cache = LoadLandblockInteriors(dats, 0xA9B30000u);

        // Cottage north room 0x102 has an exterior door at x=186 (portal poly
        // plane n=(±1,0,0), |d|=186 — dat dump 2026-06-10). Function-level pin
        // of the retail gate semantics on real dat geometry:
        var cell102 = cache.GetCellStruct(0xA9B30102u)!;

        // (a) Deep inside the room, 3 m from the door plane: the cell HAS an
        //     exterior portal but no straddle → no outdoor admission flag
        //     (retail: var_44 stays 0, add_all_outside skipped). (BR-7 C4
        //     deleted the non-retail hasExitPortal topology output — the
        //     straddle flag is the only outdoor-admission signal, like
        //     retail.)
        var farCandidates = new List<uint>();
        CellTransit.FindTransitCellsSphere(
            cache, cell102, 0xA9B30102u, new Vector3(183.0f, 86.5f, 117.0f),
            FootRadius, farCandidates, out bool farStraddle);
        Assert.False(farStraddle);

        // (b) At the door plane (0.30 m away < 0.48 radius): straddle fires.
        var nearCandidates = new List<uint>();
        CellTransit.FindTransitCellsSphere(
            cache, cell102, 0xA9B30102u, new Vector3(185.70f, 85.5f, 117.0f),
            FootRadius, nearCandidates, out bool nearStraddle);
        Assert.True(nearStraddle);
    }

    [Fact]
    public void ThresholdCottage_AdjacentClaim_LaterallyRecovers_ViaStabGraph()
    {
        var datDir = ConformanceDats.ResolveDatDir();
        if (datDir is null) { _out.WriteLine("dats unavailable — skipped"); return; }
        using var dats = new DatCollection(datDir, DatAccessType.Read);
        var cache = LoadLandblockInteriors(dats, 0xA9B40000u);

        // The #111 gate shape: claim 0x172 (adjacent room), position deep
        // inside 0x171 (the captured spawn). The sphere does not overlap
        // 0x172's volume from there → the new lateral recovery searches the
        // claim's stab list (retail find_visible_child_cell :311444) and
        // self-heals to 0x171 — instead of the old outdoor demote.
        var spawnFootCenter = new Vector3(155.390f, 11.020f, 94.0f + FootRadius);

        uint picked = CellTransit.FindCellList(cache, spawnFootCenter, FootRadius, 0xA9B40172u);
        _out.WriteLine($"pick(seed 0x172) at 0x171-interior -> 0x{picked:X8}");
        Assert.Equal(0xA9B40171u, picked);
    }
}