using OpenTK.Mathematics;
using VoxelEngine.World;
using VoxelEngine.World.Blocks;
using VoxelEngine.World.Persistence;
using Xunit;
using VoxelChunk = VoxelEngine.World.Chunk.Chunk;

namespace VoxelEngine.Tests;

public class WorldTests
{
    private static (IWorld, BlockRegistry, IChunkModificationStore) Create()
    {
        var registry = new BlockRegistry();
        var store = new InMemoryChunkModificationStore();
        IWorld world = new World.World(registry, store);
        return (world, registry, store);
    }

    [Fact]
    public void SetBlock_LoadedChunk_WritesBlockAndRecordsDiff()
    {
        var (world, registry, store) = Create();
        var chunkPos = new Vector3i(0, 0, 0);
        world.SetChunk(chunkPos, new VoxelChunk());

        bool result = world.SetBlock(2, 3, 4, registry.Stone.Id);

        Assert.True(result);
        Assert.Equal(registry.Stone.Id, world.GetBlock(2, 3, 4).Id);
        Assert.True(store.HasDiff(chunkPos));
        Assert.True(store.TryGetDiff(chunkPos, out var diff));
        int expectedIndex = (2 * VoxelChunk.Size + 3) * VoxelChunk.Size + 4;
        Assert.Equal(registry.Stone.Id, diff![expectedIndex]);
    }

    [Fact]
    public void SetBlock_UnloadedChunk_RecordsDiffButReturnsFalse()
    {
        var (world, registry, store) = Create();
        var chunkPos = new Vector3i(5, 0, 0);

        bool result = world.SetBlock(5 * VoxelChunk.Size, 0, 0, registry.Stone.Id);

        Assert.False(result);
        Assert.True(store.HasDiff(chunkPos));
    }

    [Fact]
    public void GetBlock_UnloadedChunk_ReturnsAir()
    {
        var (world, registry, _) = Create();
        Assert.Same(registry.Air, world.GetBlock(0, 0, 0));
    }

    [Fact]
    public void SetBlock_NegativeCoords_FloorsToCorrectChunk()
    {
        var (world, registry, store) = Create();
        var chunkPos = new Vector3i(-1, 0, 0);
        world.SetChunk(chunkPos, new VoxelChunk());

        bool result = world.SetBlock(-1, 0, 0, registry.Stone.Id);

        Assert.True(result);
        Assert.Equal(registry.Stone.Id, world.GetBlock(-1, 0, 0).Id);
        Assert.True(store.HasDiff(chunkPos));
    }

    [Fact]
    public void RemoveChunk_RemovesAndGetBlockReturnsAir()
    {
        var (world, registry, _) = Create();
        var chunkPos = new Vector3i(0, 0, 0);
        world.SetChunk(chunkPos, new VoxelChunk());
        world.RemoveChunk(chunkPos);

        Assert.Null(world.GetChunk(chunkPos));
        Assert.Same(registry.Air, world.GetBlock(0, 0, 0));
    }

    [Fact]
    public void ModificationStore_AccessorReturnsConstructorInjectedStore()
    {
        var (world, _, store) = Create();
        Assert.Same(store, world.ModificationStore);
    }
}