using System;
using System.IO;
using ANX.Framework.Graphics;
using ANX.Framework.NonXNA.RenderSystem;
using SharpDX.Direct3D10;

// 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.DX10
{
	public class IndexBuffer_DX10 : INativeIndexBuffer, IDisposable
	{
		private IndexElementSize size;

		public SharpDX.Direct3D10.Buffer NativeBuffer { get; private set; }

		#region Constructor
		public IndexBuffer_DX10(GraphicsDevice graphics, IndexElementSize size, int indexCount, BufferUsage usage)
		{
			this.size = size;

			//TODO: translate and use usage

			GraphicsDeviceWindowsDX10 gd10 = graphics.NativeDevice as GraphicsDeviceWindowsDX10;
			Device device = gd10 != null ? gd10.NativeDevice as Device : null;

			InitializeBuffer(device, size, indexCount, usage);
		}

		internal IndexBuffer_DX10(Device device, IndexElementSize size, int indexCount, BufferUsage usage)
		{
			this.size = size;
			InitializeBuffer(device, size, indexCount, usage);
		}
		#endregion

		#region InitializeBuffer
		private void InitializeBuffer(Device device, IndexElementSize size, int indexCount, BufferUsage usage)
		{
			BufferDescription description = new BufferDescription()
			{
				Usage = ResourceUsage.Dynamic,
				SizeInBytes = (size == IndexElementSize.SixteenBits ? 2 : 4) * indexCount,
				BindFlags = BindFlags.IndexBuffer,
				CpuAccessFlags = CpuAccessFlags.Write,
				OptionFlags = ResourceOptionFlags.None
			};

			NativeBuffer = new SharpDX.Direct3D10.Buffer(device, description);
			NativeBuffer.Unmap();
		}
		#endregion

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

		public void SetData<T>(GraphicsDevice graphicsDevice, int offsetInBytes, T[] data, int startIndex, int elementCount)
			where T : struct
		{
			//TODO: check offsetInBytes parameter for bounds etc.

			using (var stream = NativeBuffer.Map(MapMode.WriteDiscard))
			{
				if (offsetInBytes > 0)
					stream.Seek(offsetInBytes, SeekOrigin.Current);

				if (startIndex > 0 || elementCount < data.Length)
					for (int i = startIndex; i < startIndex + elementCount; i++)
						stream.Write<T>(data[i]);
				else
					for (int i = 0; i < data.Length; i++)
						stream.Write<T>(data[i]);

				NativeBuffer.Unmap();
			}
		}

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

		#region Dispose
		public void Dispose()
		{
			if (NativeBuffer != null)
			{
				NativeBuffer.Dispose();
				NativeBuffer = null;
			}
		}
		#endregion

		#region GetData
		public void GetData<T>(T[] data) where T : struct
		{
			using (var stream = NativeBuffer.Map(MapMode.Read))
			{
				stream.ReadRange(data, 0, data.Length);
				NativeBuffer.Unmap();
			}
		}

		public void GetData<T>(T[] data, int startIndex, int elementCount) where T : struct
		{
			using (var stream = NativeBuffer.Map(MapMode.Read))
			{
				stream.ReadRange(data, startIndex, elementCount);
				NativeBuffer.Unmap();
			}
		}

		public void GetData<T>(int offsetInBytes, T[] data, int startIndex, int elementCount) where T : struct
		{
			using (var stream = NativeBuffer.Map(MapMode.Read))
			{
				if (offsetInBytes > 0)
					stream.Seek(offsetInBytes, SeekOrigin.Current);

				stream.ReadRange(data, startIndex, elementCount);
				NativeBuffer.Unmap();
			}
		}
		#endregion
	}
}