using VoxelEngine.World.WorldGen;
using Xunit;

namespace VoxelEngine.Tests.WorldGen;

public class WormHashTests
{
    [Fact]
    public void Hash_IsDeterministic_ForSameInputs()
    {
        uint a = WormHash.Hash(3, -2, 7, seed: 1337);
        uint b = WormHash.Hash(3, -2, 7, seed: 1337);
        Assert.Equal(a, b);
    }

    [Fact]
    public void Hash_DiffersForDifferentCells()
    {
        uint a = WormHash.Hash(3, -2, 7, seed: 1337);
        uint b = WormHash.Hash(3, -2, 8, seed: 1337);
        Assert.NotEqual(a, b);
    }

    [Fact]
    public void Hash_DiffersForDifferentSeeds()
    {
        uint a = WormHash.Hash(3, -2, 7, seed: 1337);
        uint b = WormHash.Hash(3, -2, 7, seed: 9999);
        Assert.NotEqual(a, b);
    }

    [Fact]
    public void Hash_HandlesNegativeCoords()
    {
        // Just shouldn't throw and shouldn't collide trivially with the positive case.
        uint a = WormHash.Hash(-1, -1, -1, seed: 1);
        uint b = WormHash.Hash(1, 1, 1, seed: 1);
        Assert.NotEqual(a, b);
    }
}