using System.Collections.Generic;
using System.Numerics;
using AcDream.Core.Physics;
using Xunit;

namespace AcDream.Core.Tests.Physics;

public class CellTransitAddAllOutsideCellsTests
{
    [Fact]
    public void SphereWellInsideCell_AddsOneCell()
    {
        // Player at world (12, 12, 0) in landblock 0xA9B40000 → cell (0,0).
        // Landblock origin: 0xA9 = 169 → world X = 169*192 = 32448.
        //                  0xB4 = 180 → world Y = 180*192 = 34560.
        // Player needs to be in cell (0,0) RELATIVE to landblock origin:
        //   world X = 32448 + 12 = 32460
        //   world Y = 34560 + 12 = 34572
        var candidates = new HashSet<uint>();
        CellTransit.AddAllOutsideCells(
            worldSphereCenter: new Vector3(32460f, 34572f, 0f),
            sphereRadius: 0.5f,
            currentCellId: 0xA9B40001u,
            candidates);

        Assert.Single(candidates);
        Assert.Contains(0xA9B40001u, candidates);
    }

    [Fact]
    public void SphereAtCellEastBoundary_AddsTwoCells()
    {
        // Player at world (32448 + 23.6, 34560 + 12, 0) — near +X edge of cell (0,0).
        // Sphere reach to localX = 23.6 + 0.5 = 24.1 → cell (1,0) added.
        var candidates = new HashSet<uint>();
        CellTransit.AddAllOutsideCells(
            worldSphereCenter: new Vector3(32448f + 23.6f, 34560f + 12f, 0f),
            sphereRadius: 0.5f,
            currentCellId: 0xA9B40001u,
            candidates);

        Assert.Equal(2, candidates.Count);
        Assert.Contains(0xA9B40001u, candidates);
        // Cell (1,0): low-16 id = 1 * 8 + 0 + 1 = 9 → 0x0009.
        Assert.Contains(0xA9B40009u, candidates);
    }
}