#region Using Statements
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ANX.Framework.NonXNA;
using SharpDX.Direct3D11;
using ANX.Framework.Graphics;
using System.Runtime.InteropServices;
using ANX.Framework.NonXNA.RenderSystem;

#endregion // Using Statements

// This file is part of the ANX.Framework created by the
// "ANX.Framework developer group" and released under the Ms-PL license.
// For details see: http://anxframework.codeplex.com/license

namespace ANX.RenderSystem.Windows.DX11
{
    public class VertexBuffer_DX11 : INativeVertexBuffer, IDisposable
    {
        SharpDX.Direct3D11.Buffer buffer;
        int vertexStride;

        public VertexBuffer_DX11(GraphicsDevice graphics, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
        {
            GraphicsDeviceWindowsDX11 gd11 = graphics.NativeDevice as GraphicsDeviceWindowsDX11;
            SharpDX.Direct3D11.DeviceContext context = gd11 != null ? gd11.NativeDevice as SharpDX.Direct3D11.DeviceContext : null;

            InitializeBuffer(context.Device, vertexDeclaration, vertexCount, usage);
        }

        internal VertexBuffer_DX11(SharpDX.Direct3D11.Device device, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
        {
            InitializeBuffer(device, vertexDeclaration, vertexCount, usage);
        }

        private void InitializeBuffer(SharpDX.Direct3D11.Device device, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
        {
            this.vertexStride = vertexDeclaration.VertexStride;

            //TODO: translate and use usage

            if (device != null)
            {
                BufferDescription description = new BufferDescription()
                {
                    Usage = ResourceUsage.Dynamic,
                    SizeInBytes = vertexDeclaration.VertexStride * vertexCount,
                    BindFlags = BindFlags.VertexBuffer,
                    CpuAccessFlags = CpuAccessFlags.Write,
                    OptionFlags = ResourceOptionFlags.None
                };

                this.buffer = new SharpDX.Direct3D11.Buffer(device, description);
            }
        }

        public void SetData<T>(GraphicsDevice graphicsDevice, int offsetInBytes, T[] data, int startIndex, int elementCount) where T : struct
        {
            GraphicsDeviceWindowsDX11 dx11GraphicsDevice = graphicsDevice.NativeDevice as GraphicsDeviceWindowsDX11;
            DeviceContext context = dx11GraphicsDevice.NativeDevice;

            //TODO: check offsetInBytes parameter for bounds etc.

            GCHandle pinnedArray = GCHandle.Alloc(data, GCHandleType.Pinned);
            IntPtr dataPointer = pinnedArray.AddrOfPinnedObject();

            int dataLength = Marshal.SizeOf(typeof(T)) * data.Length;

            unsafe
            {
                using (var vData = new SharpDX.DataStream(dataPointer, dataLength, true, true))
                {
                    if (offsetInBytes > 0)
                    {
                        vData.Seek(offsetInBytes / vertexStride, System.IO.SeekOrigin.Begin);
                    }

                    SharpDX.DataStream stream;
                    SharpDX.DataBox box = context.MapSubresource(this.buffer, MapMode.WriteDiscard, MapFlags.None, out stream);
                    if (startIndex > 0 || elementCount < data.Length)
                    {
                        for (int i = startIndex; i < startIndex + elementCount; i++)
                        {
                            vData.Write<T>(data[i]);
                        }
                    }
                    else
                    {
                        vData.CopyTo(stream);
                    }
                    context.UnmapSubresource(this.buffer, 0);
                }
            }

            pinnedArray.Free();
        }

        public void SetData<T>(GraphicsDevice graphicsDevice, T[] data) where T : struct
        {
            SetData<T>(graphicsDevice, data, 0, data.Length);
        }

        public void SetData<T>(GraphicsDevice graphicsDevice, T[] data, int startIndex, int elementCount) where T : struct
        {
            SetData<T>(graphicsDevice, 0, data, startIndex, elementCount);
        }

        public SharpDX.Direct3D11.Buffer NativeBuffer
        {
            get
            {
                return this.buffer;
            }
        }

        public void Dispose()
        {
            if (this.buffer != null)
            {
                buffer.Dispose();
                buffer = null;
            }
        }

				#region INativeVertexBuffer Member

				public void GetData<T>(int offsetInBytes, T[] data, int startIndex, int elementCount, int vertexStride) where T : struct
				{
					throw new NotImplementedException();
				}

				public void SetData<T>(GraphicsDevice graphicsDevice, int offsetInBytes, T[] data, int startIndex, int elementCount, int vertexStride) where T : struct
				{
					throw new NotImplementedException();
				}

				#endregion

				#region INativeBuffer Member


				public void GetData<T>(T[] data) where T : struct
				{
					throw new NotImplementedException();
				}

				public void GetData<T>(T[] data, int startIndex, int elementCount) where T : struct
				{
					throw new NotImplementedException();
				}

				#endregion
		}
}