using System.Runtime.CompilerServices;

namespace Voxel.Core
{
    public enum Blocks : byte
    {
        Air,
        Stone,
        Dirt,
        OakPlanks,
        Grass,
        Bedrock,
        Sand,
        TNT
    }

    public enum Orientation : byte
    {
        West = 0,  // + X
        East = 1,  // - X
        Top = 2,   // + Y
        Bottom = 3,// - Y
        North = 4, // + Z
        South = 5, // - Z
    }

    public class BlockDefinition
    {
        public Blocks BlockType;
        public Textures[] FaceTextures;

        public BlockDefinition(Blocks type, Textures singleTexture)
        {
            BlockType = type;
            FaceTextures = new Textures[6];
            for (int i = 0; i < 6; i++) FaceTextures[i] = singleTexture;
        }

        public BlockDefinition(
            Blocks type,
            Textures west,
            Textures east,
            Textures top,
            Textures bottom,
            Textures north,
            Textures south
        )
        {
            BlockType = type;
            FaceTextures = new Textures[]
            {
                west, east, top, bottom, north, south
            };
        }
    }

    public static class BlockDefinitions
    {
        private static readonly BlockDefinition[] _definitions = new BlockDefinition[256];

        public static readonly Blocks[] CreativeInventory = new[]
        {
            Blocks.Stone,
            Blocks.Dirt,
            Blocks.OakPlanks,
            Blocks.Bedrock,
            Blocks.Sand,
            Blocks.TNT
        };

        static BlockDefinitions()
        {
            // simple blocks
            Define(Blocks.Stone, Textures.Stone);
            Define(Blocks.Dirt, Textures.Dirt);
            Define(Blocks.OakPlanks, Textures.OakPlanks);
            Define(Blocks.Bedrock, Textures.Bedrock);
            Define(Blocks.Sand, Textures.Sand);

            // multi-texture blocks
            // west (+X)
            // east (-X)
            // top
            // bottom
            // north (+Z)
            // south (-Z)
            Define(Blocks.Grass,
                Textures.GrassSide,
                Textures.GrassSide,
                Textures.GrassTop,
                Textures.Dirt,
                Textures.GrassSide,
                Textures.GrassSide
            );

            Define(Blocks.TNT,
                Textures.TntSide,
                Textures.TntSide,
                Textures.TntTop,
                Textures.TntBottom,
                Textures.TntSide,
                Textures.TntSide
            );
        }

        /// highly optimized getter for the hot-path (Meshing/Raycasting)
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static BlockDefinition Get(Blocks type)
        {
            return _definitions[(byte)type];
        }

        // internal helper to map the array
        private static void Define(Blocks type, Textures tex)
            => _definitions[(byte)type] = new BlockDefinition(type, tex);

        private static void Define(Blocks type, Textures w, Textures e, Textures t, Textures b, Textures n, Textures s)
            => _definitions[(byte)type] = new BlockDefinition(type, w, e, t, b, n, s);
    }
}