using StgSharp.Math;
using System;
using System.Collections.Generic;
using System.Net.Security;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;

namespace StgSharp.Graphics
{
    public partial class Form
    {
        /// <summary>
        /// Create aset of <see cref="VertexBuffer"/>.
        /// </summary>
        /// <param name="count">Amount of Object to be created.</param>
        /// <returns></returns>
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        protected VertexBuffer CreateVertexBuffer(uint count)
        {
            return new VertexBuffer(count, gl);
        }
    }

    public unsafe class VertexBuffer : IBufferObject
    {
        internal VertexBuffer(uint n, IglFunc glFunc)
        {
            _bufferID = new uint[n];
            GL = glFunc;
            fixed (uint* ptr = _bufferID)
            {
                GL.GenBuffers(n, ptr);
            }
        }

        /// <summary>
        /// 
        /// </summary>
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void Unbind()
        {
            GL.BindBuffer(BufferType.ARRAY_BUFFER, 0);
        }

        public sealed override void Bind(int index)
        {
            GL.BindBuffer(BufferType.ARRAY_BUFFER, (uint)index);
        }

        internal void ChangeEnvironment(IglFunc gl)
        {
            GL = gl;
        }

        protected sealed override void Dispose(bool disposing)
        {
            if (disposing)
            {
                fixed (uint* id = _bufferID)
                {
                    GL.DeleteBuffers((uint)_bufferID.Length, _bufferID);
                }
            }
        }

        /// <summary>
        /// Set data to current vertex buffer object
        /// </summary>
        /// <typeparam name="T">Type of bufferData</typeparam>
        /// <param name="index">Index to find certain VBO in this instance</param>
        /// <param name="bufferData">Data to write in</param>
        /// <param name="usage">How OpenGL use these data, defined by <see cref="BufferUsage"/></param>
        public void SetValue<T>(int index, T bufferData, BufferUsage usage) where T : IMat
        {
            GL.BindBuffer(BufferType.ARRAY_BUFFER, _bufferID[index]);
            GL.SetBufferData(BufferType.ARRAY_BUFFER, bufferData, usage);

        }

        /// <summary>
        /// Set data to current vertex buffer object
        /// </summary>
        /// <typeparam name="T">Type of bufferData</typeparam>
        /// <param name="index">Index to find certain VBO in this instance</param>
        /// <param name="bufferArray">A array of data to write in</param>
        /// <param name="usage">How OpenGL use these data, defined by <see cref="BufferUsage"/></param>
        public void SetValueArray<T>(int index, T[] bufferArray, BufferUsage usage) where T : struct, IConvertible
        {
            GL.BindBuffer(BufferType.ARRAY_BUFFER, _bufferID[index]);
            GL.SetBufferData(BufferType.ARRAY_BUFFER, bufferArray, usage);
        }
    }
}