using OpenTK.Graphics.OpenGL4;

namespace Voxel
{
    static class Renderer
    {
        private static int _ssbo;
        private static int _vao;
        private static List<ChunkMesh> _chunkMeshes = new List<ChunkMesh>();
        private static Shader _shader;
        private static Texture _texture;
        private static bool _needsUpdate = false;

        static Renderer()
        {
            string vertexPath = "Shaders/shader.vert";
            string fragmentPath = "Shaders/shader.frag";
            string texturePath = "atlas.png";

            _shader = new Shader(vertexPath, fragmentPath);
            _texture = new Texture(texturePath);

            _shader.SetInt("uTexture", 0);

            _ssbo = GL.GenBuffer();
            _vao = GL.GenVertexArray();

            GL.BindVertexArray(_vao);
            GL.BindBuffer(BufferTarget.ShaderStorageBuffer, _ssbo);
            GL.BindBufferBase(BufferRangeTarget.ShaderStorageBuffer, 0, _ssbo);
        }

        public static void Render()
        {
            GL.BindVertexArray(_vao);
            GL.BindBuffer(BufferTarget.ShaderStorageBuffer, _ssbo);

            //if (_needsUpdate)
            //{
            //    _needsUpdate = false;
            //    byte[] data = _faces.SelectMany(f => f.Pack()).ToArray();
            //    GL.BufferData(BufferTarget.ShaderStorageBuffer, data.Length, data, BufferUsageHint.StaticRead);
            //}

            _shader.Use();
            _shader.SetMatrix4("view", Camera.view);
            _shader.SetMatrix4("projection", Camera.projection);

            for (int i = 0; i < _chunkMeshes.Count; i++)
            {
                ChunkMesh chunkMesh = _chunkMeshes[i];
                _shader.SetInt("chunkX", chunkMesh.X);
                _shader.SetInt("chunkY", chunkMesh.Y);
                GL.BufferData(BufferTarget.ShaderStorageBuffer, chunkMesh.PackedData.Length, chunkMesh.PackedData, BufferUsageHint.StaticRead);
                GL.DrawArrays(PrimitiveType.Triangles, 0, chunkMesh.Length * 6);
            }

            //Console.WriteLine("Rendered " + _faces.Count.ToString() + " faces");
        }

        public static void AddChunkMesh(ChunkMesh chunkMesh)
        {
            _chunkMeshes.Add(chunkMesh);
        }
    }
}