ModernUO/Projects/UOContent.Tests/Tests/Engines/Pathing/Multi/MultiMaskCacheTests.cs

using System;
using Server.Engines.Pathing.Cache;
using Server.Items;
using Server.Tests.Terrain;
using Xunit;

namespace Server.Tests.Pathfinding;

[Collection("Sequential Pathfinding Tests")]
public class MultiMaskCacheTests : IDisposable
{
    private const int MapId = 1;
    private const int GuildHouseId = TestMultis.GuildHouse;
    private const int PlaceX = 1480;
    private const int PlaceY = 1620;

    private readonly StepCacheStateScope _cacheState = new();

    public void Dispose() => _cacheState.Dispose();

    [Fact]
    public void TryResolveCoveringMulti_FindsPlacedMulti_AndLocalIndices()
    {
        StepCache.Instance.Clear();
        var map = Map.Maps[MapId];
        map.GetAverageZ(PlaceX, PlaceY, out _, out var z, out _);
        var loc = new Point3D(PlaceX, PlaceY, (sbyte)z);
        var multi = new TestMulti(GuildHouseId);
        try
        {
            multi.MoveToWorld(loc, map);

            Assert.True(MultiMaskCache.TryResolveCoveringMulti(map, PlaceX, PlaceY, out var found, out var lx, out var ly));
            Assert.Same(multi, found);
            var mcl = multi.Components;
            Assert.Equal(PlaceX - multi.X - mcl.Min.X, lx);
            Assert.Equal(PlaceY - multi.Y - mcl.Min.Y, ly);

            Assert.False(MultiMaskCache.TryResolveCoveringMulti(map, PlaceX + 200, PlaceY + 200, out _, out _, out _));
        }
        finally
        {
            multi.Delete();
        }
    }

    [Fact]
    public void LocalWorldZ_RoundTrips_AndPreservesMasks()
    {
        var world = new StepMask(
            walkMask: 0b1010_1010, wetMask: 0b0101_0101,
            walkZN: 10, walkZNE: 11, walkZE: 12, walkZSE: 13, walkZS: 14, walkZSW: 15, walkZW: 16, walkZNW: 17,
            swimZN: -1, swimZNE: -2, swimZE: -3, swimZSE: -4, swimZS: -5, swimZSW: -6, swimZW: -7, swimZNW: -8
        );
        const int multiZ = 7;

        Assert.True(MultiMaskCache.TryToLocalZ(world, multiZ, out var local));
        var back = MultiMaskCache.ToWorldZ(local, multiZ);

        Assert.Equal(world.WalkMask, back.WalkMask);
        Assert.Equal(world.WetMask, back.WetMask);
        for (var d = 0; d < 8; d++)
        {
            Assert.Equal(world.GetWalkZ((Direction)d), back.GetWalkZ((Direction)d));
            Assert.Equal(world.GetSwimZ((Direction)d), back.GetSwimZ((Direction)d));
        }
    }

    [Fact]
    public void TryToLocalZ_RejectsOverflow()
    {
        var world = new StepMask(
            walkMask: 0xFF, wetMask: 0,
            walkZN: 100, walkZNE: 0, walkZE: 0, walkZSE: 0, walkZS: 0, walkZSW: 0, walkZW: 0, walkZNW: 0,
            swimZN: 0, swimZNE: 0, swimZE: 0, swimZSE: 0, swimZS: 0, swimZSW: 0, swimZW: 0, swimZNW: 0
        );
        Assert.False(MultiMaskCache.TryToLocalZ(world, -100, out _));
    }

    [Fact]
    public void TerrainTopBelow_TrueWhenFloorWellAboveGround()
    {
        StepCache.Instance.Clear();
        var map = Map.Maps[MapId];
        map.GetAverageZ(PlaceX, PlaceY, out _, out var ground, out _);

        // Floor far above ground → terrain is below → guard passes.
        Assert.True(MultiMaskCache.TerrainTopBelow(map, PlaceX, PlaceY, (sbyte)(ground + 50)));
        // Floor at/below ground → terrain reaches the envelope → guard fails.
        Assert.False(MultiMaskCache.TerrainTopBelow(map, PlaceX, PlaceY, (sbyte)(ground - 50)));
    }

    [Fact]
    public void PathThroughHouseInterior_IncrementsMultiMaskCacheHits()
    {
        // On flat default ground the house is footprint-clean, so its interior cells serve from the cache.
        var map = Map.Maps[MapId];
        map.GetAverageZ(PlaceX, PlaceY, out _, out var z, out _);
        var houseLoc = new Point3D(PlaceX, PlaceY, (sbyte)z);
        var multi = new TestMulti(GuildHouseId);
        Server.Systems.FeatureFlags.ContentFeatureFlags.BitmapPathfindingCache = true;
        var mover = MultiTestSupport.GetWalkerOracle(map, new Point3D(PlaceX, PlaceY + 10, (sbyte)z));
        try
        {
            multi.MoveToWorld(houseLoc, map);
            Assert.True(MultiMaskCache.ComputeFootprintClean(map, multi),
                "precondition: the house must be footprint-clean for the cache to serve");
            StepCache.Instance.Clear();

            var start = new Point3D(PlaceX, PlaceY + 10, (sbyte)z);
            var goal = new Point3D(PlaceX, PlaceY - 10, (sbyte)z);
            // First pass builds the interior cache (live synth); second pass should hit it.
            Server.PathAlgorithms.BitmapAStarAlgorithm.Instance.Find(mover, map, start, goal);

            var before = StepCache.Instance.GetStats().MultiMaskCacheHits;
            Server.PathAlgorithms.BitmapAStarAlgorithm.Instance.Find(mover, map, start, goal);
            var after = StepCache.Instance.GetStats().MultiMaskCacheHits;

            Assert.True(after > before, $"expected MultiMaskCacheHits to increase, before={before} after={after}");
        }
        finally
        {
            mover.Delete();
            multi.Delete();
        }
    }

    [Fact]
    public void ClutteredHouse_DoesNotServeCache_ButStillPaths()
    {
        // A rock taller than the house floor, inside the footprint, dirties it.
        using var terrain = TestTerrain.Scope();
        TestTerrain.AddStatic(PlaceX + 1, PlaceY + 1, TestTiles.Rock, 0);

        var map = Map.Maps[MapId];
        map.GetAverageZ(PlaceX, PlaceY, out _, out var z, out _);
        var multi = new TestMulti(GuildHouseId);
        Server.Systems.FeatureFlags.ContentFeatureFlags.BitmapPathfindingCache = true;
        var mover = MultiTestSupport.GetWalkerOracle(map, new Point3D(PlaceX, PlaceY + 10, (sbyte)z));
        try
        {
            // The rock pokes through the floor → footprint dirty → cache must NOT serve.
            multi.MoveToWorld(new Point3D(PlaceX, PlaceY, (sbyte)z), map);
            Assert.False(MultiMaskCache.ComputeFootprintClean(map, multi),
                "precondition: the rock must make the house footprint-dirty for this test to be meaningful");
            StepCache.Instance.Clear();

            var start = new Point3D(PlaceX, PlaceY + 10, (sbyte)z);
            var goal = new Point3D(PlaceX, PlaceY - 10, (sbyte)z);
            Server.PathAlgorithms.BitmapAStarAlgorithm.Instance.Find(mover, map, start, goal); // warm
            var before = StepCache.Instance.GetStats().MultiMaskCacheHits;
            var path = Server.PathAlgorithms.BitmapAStarAlgorithm.Instance.Find(mover, map, start, goal);
            var after = StepCache.Instance.GetStats().MultiMaskCacheHits;

            Assert.NotNull(path);          // pathfinding still works (degraded to live-synth)
            Assert.Equal(before, after);   // dirty footprint → zero cache serves
        }
        finally
        {
            mover.Delete();
            multi.Delete();
        }
    }

    [Fact]
    public void PathInteriorCacheState_ResetsOnMove()
    {
        var map = Map.Maps[MapId];
        var multi = new TestMulti(GuildHouseId);
        try
        {
            multi.MoveToWorld(new Point3D(PlaceX, PlaceY, 0), map);
            multi.PathInteriorCacheState = MultiInteriorCacheState.Clean;

            // A move changes the footprint's world terrain, so the gate must reset to Unknown and
            // recompute on next use. (BaseMulti.OnLocationChange does this; subclasses like BaseHouse
            // and BaseBoat must call base for it to fire — this pins that contract.)
            multi.MoveToWorld(new Point3D(PlaceX + 8, PlaceY + 8, 0), map);
            Assert.Equal(MultiInteriorCacheState.Unknown, multi.PathInteriorCacheState);
        }
        finally
        {
            multi.Delete();
        }
    }

    [Fact]
    public void PathInteriorCacheState_ResetsOnItemIdChange()
    {
        var map = Map.Maps[MapId];
        var multi = new TestMulti(GuildHouseId);
        try
        {
            multi.MoveToWorld(new Point3D(PlaceX, PlaceY, 0), map);
            multi.PathInteriorCacheState = MultiInteriorCacheState.Clean;

            // Changing ItemID swaps the footprint (e.g. a boat changing heading), so the gate must
            // reset to recompute cleanliness for the new shape.
            multi.ItemID = TestMultis.Tower;
            Assert.Equal(MultiInteriorCacheState.Unknown, multi.PathInteriorCacheState);
        }
        finally
        {
            multi.Delete();
        }
    }

    [Fact]
    public void ComputeFootprintClean_TrueAtNormalPlacement_FalseWhenSunk()
    {
        StepCache.Instance.Clear();
        var map = Map.Maps[MapId];
        map.GetAverageZ(PlaceX, PlaceY, out _, out var ground, out _);

        var normal = new TestMulti(GuildHouseId);
        var sunk = new TestMulti(GuildHouseId);
        try
        {
            normal.MoveToWorld(new Point3D(PlaceX, PlaceY, (sbyte)ground), map);
            Assert.True(MultiMaskCache.ComputeFootprintClean(map, normal));

            sunk.MoveToWorld(new Point3D(PlaceX + 60, PlaceY, (sbyte)(ground - 40)), map);
            Assert.False(MultiMaskCache.ComputeFootprintClean(map, sunk));
        }
        finally
        {
            normal.Delete();
            sunk.Delete();
        }
    }
}