using AcDream.Core.Physics;
using Xunit;

namespace AcDream.Core.Tests.Physics;

public class PhysicsEngineIsLandblockLoadedTests
{
    private static TerrainSurface MakeFlatTerrain()
    {
        var heights = new byte[81];
        Array.Fill(heights, (byte)50);
        var heightTable = new float[256];
        for (int i = 0; i < 256; i++) heightTable[i] = i * 1f;
        return new TerrainSurface(heights, heightTable);
    }

    [Fact]
    public void IsLandblockLoaded_AbsentId_ReturnsFalse()
    {
        var engine = new PhysicsEngine();
        Assert.False(engine.IsLandblockLoaded(0xA9B4FFFFu));
    }

    [Fact]
    public void IsLandblockLoaded_AddedId_ReturnsTrue()
    {
        var engine = new PhysicsEngine();
        engine.AddLandblock(0xA9B4FFFFu, MakeFlatTerrain(),
            Array.Empty<CellSurface>(), Array.Empty<PortalPlane>(),
            worldOffsetX: 0f, worldOffsetY: 0f);

        Assert.True(engine.IsLandblockLoaded(0xA9B4FFFFu));
    }

    [Fact]
    public void IsLandblockLoaded_AnotherIdAbsent_ReturnsFalse()
    {
        var engine = new PhysicsEngine();
        engine.AddLandblock(0xA9B4FFFFu, MakeFlatTerrain(),
            Array.Empty<CellSurface>(), Array.Empty<PortalPlane>(),
            worldOffsetX: 0f, worldOffsetY: 0f);

        Assert.False(engine.IsLandblockLoaded(0xDEADBEEFu));
    }

    [Fact]
    public void IsLandblockLoaded_AfterRemove_ReturnsFalse()
    {
        var engine = new PhysicsEngine();
        engine.AddLandblock(0xA9B4FFFFu, MakeFlatTerrain(),
            Array.Empty<CellSurface>(), Array.Empty<PortalPlane>(),
            worldOffsetX: 0f, worldOffsetY: 0f);
        engine.RemoveLandblock(0xA9B4FFFFu);

        Assert.False(engine.IsLandblockLoaded(0xA9B4FFFFu));
    }
}