using System.Collections.Generic;
using System.Numerics;
using AcDream.App.Rendering;
using AcDream.Core.World;
using Xunit;

namespace AcDream.App.Tests.Rendering;

public class InteriorEntityPartitionTests
{
    private const uint CellA = 0xA9B40170;
    private const uint CellB = 0xA9B40171;

    private static WorldEntity Ent(uint id, uint serverGuid, uint? parentCell) => new()
    {
        Id = id,
        ServerGuid = serverGuid,
        SourceGfxObjOrSetupId = 0x01000001,
        Position = Vector3.Zero,
        Rotation = Quaternion.Identity,
        MeshRefs = new[] { new MeshRef(0x01000001, Matrix4x4.Identity) },
        ParentCellId = parentCell,
    };

    private static IEnumerable<(uint, Vector3, Vector3, IReadOnlyList<WorldEntity>,
        IReadOnlyDictionary<uint, WorldEntity>?)> OneLb(uint lbId, params WorldEntity[] ents)
        => new[] { (lbId, Vector3.Zero, Vector3.Zero, (IReadOnlyList<WorldEntity>)ents,
                    (IReadOnlyDictionary<uint, WorldEntity>?)null) };

    [Fact]
    public void Partitions_ByServerGuidThenParentCell_IntoThreeBuckets()
    {
        var livePlayer = Ent(1, serverGuid: 0x5000000A, parentCell: null);     // live-dynamic
        var liveNpcInCell = Ent(2, serverGuid: 0x80001234, parentCell: CellA); // live-dynamic WINS over cell
        var staticA = Ent(3, serverGuid: 0, parentCell: CellA);                // per-cell static
        var staticB = Ent(4, serverGuid: 0, parentCell: CellB);                // per-cell static
        var scenery = Ent(5, serverGuid: 0, parentCell: null);                 // outdoor scenery

        var visible = new HashSet<uint> { CellA, CellB };
        var result = InteriorEntityPartition.Partition(
            visible, OneLb(0xA9B4FFFF, livePlayer, liveNpcInCell, staticA, staticB, scenery));

        Assert.Equal(2, result.LiveDynamic.Count);                 // player + npc (serverGuid != 0)
        Assert.Contains(livePlayer, result.LiveDynamic);
        Assert.Contains(liveNpcInCell, result.LiveDynamic);

        Assert.Single(result.ByCell[CellA]);                       // only staticA (npc went live-dynamic)
        Assert.Contains(staticA, result.ByCell[CellA]);
        Assert.Single(result.ByCell[CellB]);
        Assert.Contains(staticB, result.ByCell[CellB]);

        Assert.Single(result.Outdoor);
        Assert.Contains(scenery, result.Outdoor);
    }

    [Fact]
    public void Static_InNonVisibleCell_IsDropped()
    {
        var staticHidden = Ent(3, serverGuid: 0, parentCell: 0xA9B40199); // not in the visible set
        var visible = new HashSet<uint> { CellA };
        var result = InteriorEntityPartition.Partition(visible, OneLb(0xA9B4FFFF, staticHidden));

        Assert.False(result.ByCell.ContainsKey(0xA9B40199));
        Assert.Empty(result.Outdoor);
        Assert.Empty(result.LiveDynamic);
    }

    [Fact]
    public void EntityWithNoMeshRefs_IsSkipped()
    {
        var noMesh = new WorldEntity
        {
            Id = 9, ServerGuid = 0, SourceGfxObjOrSetupId = 0x01000001,
            Position = Vector3.Zero, Rotation = Quaternion.Identity,
            MeshRefs = System.Array.Empty<MeshRef>(), ParentCellId = CellA,
        };
        var result = InteriorEntityPartition.Partition(
            new HashSet<uint> { CellA }, OneLb(0xA9B4FFFF, noMesh));

        Assert.False(result.ByCell.ContainsKey(CellA));
    }
}