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

namespace AcDream.Core.Tests.Conformance;

/// <summary>
/// #107 (2026-06-10): the indoor-login spawn wedge. The live capture
/// (resolve-107-login1.jsonl) showed ACE restoring the player with a POISONED
/// (cell, position) pair — cell id 0xA9B40162 (a different building, ~55 m
/// away) with a position inside cell 0xA9B40171 (the threshold cottage). The
/// unvalidated claim left the player fake-grounded (no contact plane, no
/// walkable polygon); the first movement demoted them to outdoor mid-building
/// and they fell 2.4 m through the cottage floor onto the terrain underneath.
///
/// These tests pin the dat-level facts that drove the fix (the retail
/// AdjustPosition validation at the player snap, PhysicsEngine.Resolve head):
/// the position is genuinely inside 0x171, genuinely NOT inside 0x162's
/// visible graph, and the production pick recovers correctly from a GOOD seed
/// while demoting to outdoor from the poisoned one (retail-identical: retail's
/// find_visible_child_cell also cannot recover a cross-building claim and
/// falls to seen_outside → adjust_to_outside, acclient :280037).
/// </summary>
public sealed class Issue107SpawnDiagnosticTests
{
    private readonly ITestOutputHelper _out;
    public Issue107SpawnDiagnosticTests(ITestOutputHelper output) => _out = output;

    private const float FootRadius = 0.48f;   // capture input.sphereRadius
    private const uint PoisonedClaim = 0xA9B40162u;   // the inn-side cell ACE reported
    private const uint ActualCell    = 0xA9B40171u;   // the cell that contains the position

    /// <summary>The captured spawn position (A9B4-local == capture world frame).</summary>
    private static readonly Vector3 Spawn = new(156.53314f, 11.775104f, 96.5f);

    [Fact]
    public void SpawnPosition_IsInside0171_NotInside0162_PickRecoversFromGoodSeed()
    {
        var datDir = ConformanceDats.ResolveDatDir();
        if (datDir is null) { _out.WriteLine("dats unavailable — skipped"); return; }
        using var dats = new DatCollection(datDir, DatAccessType.Read);
        var cache = new PhysicsDataCache();

        var containing = new List<uint>();
        int loaded = 0;
        for (uint low = 0x0100; low <= 0x01FF; low++)
        {
            uint cellId = 0xA9B40000u | low;
            EnvCell cell;
            try { cell = ConformanceDats.LoadEnvCell(dats, cache, cellId); }
            catch { continue; }
            loaded++;
            if (cell.PointInCell(Spawn + new Vector3(0, 0, FootRadius)))
            {
                containing.Add(cellId);
                _out.WriteLine($"cell 0x{cellId:X8} CONTAINS spawn footCenter");
            }
        }
        Assert.True(loaded > 0, "expected Holtburg interior cells to load");

        // The poisoned-pair facts: position inside 0x171, NOT inside 0x162.
        Assert.Contains(ActualCell, containing);
        Assert.DoesNotContain(PoisonedClaim, containing);

        var footCenter = Spawn + new Vector3(0, 0, FootRadius);

        // Production pick with the GOOD seed keeps the player indoor.
        uint pickGood = CellTransit.FindCellList(cache, footCenter, FootRadius, ActualCell);
        _out.WriteLine($"FindCellList(seed=0x{ActualCell:X8}) -> 0x{pickGood:X8}");
        Assert.Equal(ActualCell, pickGood);

        // Production pick with the POISONED seed demotes to the outdoor column —
        // retail-identical for a cross-building claim (0x171 is not in 0x162's
        // stab list). The login-side fix is AdjustPosition at the snap, which
        // demotes IMMEDIATELY instead of after the first movement.
        uint pickBad = CellTransit.FindCellList(cache, footCenter, FootRadius, PoisonedClaim);
        _out.WriteLine($"FindCellList(seed=0x{PoisonedClaim:X8}) -> 0x{pickBad:X8}");
        Assert.Equal(0xA9B40031u, pickBad);
    }

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

        ConformanceDats.LoadEnvCell(dats, cache, ActualCell);
        ConformanceDats.LoadEnvCell(dats, cache, PoisonedClaim);

        var room = cache.GetCellStruct(ActualCell);
        Assert.NotNull(room);
        // 0x171 is a ground-floor cottage room with an exterior doorway —
        // retail marks it seen_outside; AdjustPosition's indoor not-found
        // fallback (acclient :280037) depends on this flag being cached.
        Assert.True(room!.SeenOutside, "0xA9B40171 should be seen_outside");
        _out.WriteLine($"0x{ActualCell:X8}.SeenOutside={room.SeenOutside}");

        var inn = cache.GetCellStruct(PoisonedClaim);
        Assert.NotNull(inn);
        _out.WriteLine($"0x{PoisonedClaim:X8}.SeenOutside={inn!.SeenOutside}");
    }

    [Fact]
    public void AdjacentRoomClaim_CorrectsToContainingRoom_ViaStabList()
    {
        // 2026-06-10 gate-run regression: ACE saved the cell one room off
        // (claim 0xA9B40172, position inside 0xA9B40171 — adjacent rooms of the
        // threshold cottage, connected via the 20 cm threshold cell 0x173).
        // With every cell hydrated, retail's find_visible_child_cell stab-list
        // search (acclient :311444) must correct the claim. The live failure
        // was the auto-entry hold opening before 0x171 hydrated (the
        // mid-population "any cell present" disambiguator, since removed) —
        // this test pins the hydrated-path correctness.
        var datDir = ConformanceDats.ResolveDatDir();
        if (datDir is null) { _out.WriteLine("dats unavailable — skipped"); return; }
        using var dats = new DatCollection(datDir, DatAccessType.Read);
        var cache = new PhysicsDataCache();
        for (uint low = 0x0100; low <= 0x01FF; low++)
        {
            try { ConformanceDats.LoadEnvCell(dats, cache, 0xA9B40000u | low); }
            catch { }
        }

        // The gate-run spawn point (ACE save: cell 0x172, position in 0x171).
        var spawnFootCenter = new Vector3(155.390f, 11.020f, 94.0f + FootRadius);

        uint corrected = CellTransit.FindVisibleChildCell(
            cache, 0xA9B40172u, spawnFootCenter, useStabList: true);
        _out.WriteLine($"FindVisibleChildCell(claim 0x172, stab) -> 0x{corrected:X8}");
        Assert.Equal(ActualCell, corrected);
    }

    [Fact]
    public void PoisonedClaim_IsADifferentBuilding_55mAway()
    {
        var datDir = ConformanceDats.ResolveDatDir();
        if (datDir is null) { _out.WriteLine("dats unavailable — skipped"); return; }
        using var dats = new DatCollection(datDir, DatAccessType.Read);

        var claim = dats.Get<DatReaderWriter.DBObjs.EnvCell>(PoisonedClaim);
        var actual = dats.Get<DatReaderWriter.DBObjs.EnvCell>(ActualCell);
        Assert.NotNull(claim);
        Assert.NotNull(actual);

        float dist = Vector3.Distance(claim!.Position.Origin, actual!.Position.Origin);
        _out.WriteLine(
            $"claim origin=({claim.Position.Origin.X:F1},{claim.Position.Origin.Y:F1}) " +
            $"actual origin=({actual.Position.Origin.X:F1},{actual.Position.Origin.Y:F1}) dist={dist:F1} m");
        // The pair is not a one-tick-stale neighbour confusion — the buildings
        // are tens of metres apart. The poisoning happened on the WIRE side
        // (the old position-derived-landblock wireCellId composition) or in a
        // prior wedged session's chaos, not in the per-tick membership pick.
        Assert.True(dist > 20f, $"expected cross-building distance, got {dist:F1} m");
    }
}