using System;
using System.Runtime.InteropServices;
using ANX.Framework.Graphics;
using ANX.Framework.NonXNA.RenderSystem;
using Dx11 = SharpDX.Direct3D11;

// 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.Metro
{
	public class VertexBuffer_Metro : INativeVertexBuffer, IDisposable
	{
		Dx11.Buffer buffer;
		int vertexStride;

		public VertexBuffer_Metro(GraphicsDevice graphics, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
		{
			GraphicsDeviceWindowsMetro gdMetro = graphics.NativeDevice as GraphicsDeviceWindowsMetro;
			Dx11.Device1 device = gdMetro.NativeDevice.NativeDevice;

			InitializeBuffer(device, vertexDeclaration, vertexCount, usage);
		}

		internal VertexBuffer_Metro(Dx11.Device device, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
		{
			InitializeBuffer(device, vertexDeclaration, vertexCount, usage);
		}

		private void InitializeBuffer(Dx11.Device device, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
		{
			this.vertexStride = vertexDeclaration.VertexStride;

			//TODO: translate and use usage

			if (device != null)
			{
				var description = new Dx11.BufferDescription()
					{
						Usage = Dx11.ResourceUsage.Dynamic,
						SizeInBytes = vertexDeclaration.VertexStride * vertexCount,
						BindFlags = Dx11.BindFlags.VertexBuffer,
						CpuAccessFlags = Dx11.CpuAccessFlags.Write,
						OptionFlags = Dx11.ResourceOptionFlags.None
					};

				this.buffer = new Dx11.Buffer(device, description);
			}
		}

		public void SetData<T>(GraphicsDevice graphicsDevice, int offsetInBytes, T[] data, int startIndex, int elementCount) where T : struct
		{
			GraphicsDeviceWindowsMetro gdMetro = graphicsDevice.NativeDevice as GraphicsDeviceWindowsMetro;
			Dx11.Device1 device = gdMetro.NativeDevice.NativeDevice;
			Dx11.DeviceContext1 context = gdMetro.NativeDevice.NativeContext;

			//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, Dx11.MapMode.WriteDiscard, Dx11.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 Dx11.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
	}
}