using System;
using ANX.Framework;
using ANX.Framework.Graphics;
using ANX.Framework.NonXNA;
using SharpDX.DXGI;
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 GraphicsDeviceWindowsMetro : INativeGraphicsDevice
	{
		#region Constants
		private const float ColorMultiplier = 1f / 255f;
		#endregion
		
		#region Private
		internal EffectTechnique_Metro currentTechnique;
		private VertexBuffer currentVertexBuffer;
		private Dx11.Viewport currentViewport;
		private uint lastClearColor;
		private SharpDX.Color4 clearColor;
		private bool vSyncEnabled;

		internal NativeDxDevice NativeDevice
		{
			get;
			private set;
		}
		#endregion

		#region Public
		public bool VSync
		{
			get
			{
				return this.vSyncEnabled;
			}
			set
			{
				this.vSyncEnabled = value;
			}
		}

        public Rectangle ScissorRectangle
        {
            get { throw new NotImplementedException(); }
            set { throw new NotImplementedException(); }
        }
		#endregion

		#region Constructor
		public GraphicsDeviceWindowsMetro(PresentationParameters presentationParameters)
		{
			this.vSyncEnabled = true;

			NativeDevice = new NativeDxDevice(presentationParameters);
			
			ResizeRenderWindow(presentationParameters);

			currentViewport = new Dx11.Viewport(0, 0,
				presentationParameters.BackBufferWidth,
				presentationParameters.BackBufferHeight);
		}
		#endregion

		#region Clear
		public void Clear(ref Color color)
		{
			uint newClearColor = color.PackedValue;
			if (lastClearColor != newClearColor)
			{
				lastClearColor = newClearColor;
				clearColor.Red = color.R * ColorMultiplier;
				clearColor.Green = color.G * ColorMultiplier;
				clearColor.Blue = color.B * ColorMultiplier;
				clearColor.Alpha = color.A * ColorMultiplier;
			}

			NativeDevice.Clear(clearColor);
		}

		public void Clear(ClearOptions options, Vector4 color, float depth, int stencil)
		{
			if ((options & ClearOptions.Target) == ClearOptions.Target)
			{
				// Clear a RenderTarget (or BackBuffer)

				this.clearColor.Red = color.X;
				this.clearColor.Green = color.Y;
				this.clearColor.Blue = color.Z;
				this.clearColor.Alpha = color.W;
				this.lastClearColor = 0;

				NativeDevice.Clear(clearColor);
			}

			if ((options | ClearOptions.Stencil | ClearOptions.DepthBuffer) == options)
			{
				// Clear the stencil buffer

				NativeDevice.ClearDepthAndStencil(Dx11.DepthStencilClearFlags.Depth | Dx11.DepthStencilClearFlags.Stencil, depth, (byte)stencil);
			}
			else if ((options | ClearOptions.Stencil) == options)
			{
				NativeDevice.ClearDepthAndStencil(Dx11.DepthStencilClearFlags.Stencil, depth, (byte)stencil);
			}
			else
			{
				NativeDevice.ClearDepthAndStencil(Dx11.DepthStencilClearFlags.Depth, depth, (byte)stencil);
			}
		}

		#endregion

		#region Present
		public void Present()
		{
			NativeDevice.Present(this.vSyncEnabled ? 1 : 0);
		}

		#endregion

        #region DrawIndexedPrimitives
        public void DrawIndexedPrimitives(PrimitiveType primitiveType, int baseVertex,
            int minVertexIndex, int numVertices, int startIndex, int primitiveCount, IndexBuffer indexBuffer)
        {
            SetInputLayout();
            ApplyPrimitiveType(primitiveType);
            NativeDevice.SetDefaultTargets();

            if (indexBuffer != null)
            {
                SetIndexBuffer(indexBuffer);
            }

            int indexCount = CalculateVertexCount(primitiveType, primitiveCount);
            for (int passIndex = 0; passIndex < currentTechnique.PassCount; passIndex++)
            {
                currentTechnique[passIndex].Apply(NativeDevice);
                NativeDevice.NativeContext.DrawIndexed(indexCount, startIndex, baseVertex);
            }
        }
        #endregion

        #region DrawPrimitives
        public void DrawPrimitives(PrimitiveType primitiveType, int vertexOffset, int primitiveCount)
        {
            SetInputLayout();
            ApplyPrimitiveType(primitiveType);
            NativeDevice.SetDefaultTargets();

            for (int passIndex = 0; passIndex < currentTechnique.PassCount; passIndex++)
            {
                currentTechnique[passIndex].Apply(NativeDevice);
                NativeDevice.NativeContext.Draw(primitiveCount, vertexOffset);
			}
		}
		#endregion

		#region DrawInstancedPrimitives
		public void DrawInstancedPrimitives(PrimitiveType primitiveType,
			int baseVertex, int minVertexIndex, int numVertices, int startIndex,
            int primitiveCount, int instanceCount, IndexBuffer indexBuffer)
		{
			NativeDevice.NativeContext.DrawIndexedInstanced(numVertices,
				instanceCount, startIndex, baseVertex, 0);
		}

		#endregion // DrawInstancedPrimitives

		#region DrawUserIndexedPrimitives<T>
		public void DrawUserIndexedPrimitives<T>(PrimitiveType primitiveType, T[] vertexData,
			int vertexOffset, int numVertices, Array indexData, int indexOffset, int primitiveCount,
			VertexDeclaration vertexDeclaration, IndexElementSize indexFormat)
			where T : struct, IVertexType
		{
			int vertexCount = vertexData.Length;
			int indexCount = indexData.Length;
			VertexBuffer_Metro vb11 = new VertexBuffer_Metro(NativeDevice.NativeDevice, vertexDeclaration, vertexCount, BufferUsage.None);
			vb11.SetData<T>(null, vertexData);

			Dx11.VertexBufferBinding nativeVertexBufferBindings = new Dx11.VertexBufferBinding(vb11.NativeBuffer, vertexDeclaration.VertexStride, 0);

			NativeDevice.NativeContext.InputAssembler.SetVertexBuffers(0, nativeVertexBufferBindings);

			IndexBuffer_Metro idxMetro = new IndexBuffer_Metro(NativeDevice.NativeDevice, indexFormat, indexCount, BufferUsage.None);
            IndexElementSize indexElementSize;
			if (indexData.GetType() == typeof(Int16[]))
			{
				idxMetro.SetData<short>(null, (short[])indexData);
                indexElementSize = IndexElementSize.SixteenBits;
			}
			else
			{
				idxMetro.SetData<int>(null, (int[])indexData);
                indexElementSize = IndexElementSize.ThirtyTwoBits;
			}

            NativeDevice.NativeContext.InputAssembler.SetIndexBuffer(idxMetro.NativeBuffer, FormatConverter.Translate(indexElementSize), 0);

			DrawIndexedPrimitives(primitiveType, 0, vertexOffset, numVertices, indexOffset, primitiveCount, null);
		}

		#endregion // DrawUserIndexedPrimitives<T>

		#region DrawUserPrimitives<T>
		public void DrawUserPrimitives<T>(PrimitiveType primitiveType, T[] vertexData, int vertexOffset,
			int primitiveCount, VertexDeclaration vertexDeclaration) where T : struct, IVertexType
		{
			int vertexCount = vertexData.Length;
			VertexBuffer_Metro vbMetro = new VertexBuffer_Metro(NativeDevice.NativeDevice,
				vertexDeclaration, vertexCount, BufferUsage.None);
			vbMetro.SetData<T>(null, vertexData);

			Dx11.VertexBufferBinding nativeVertexBufferBindings = new Dx11.VertexBufferBinding(
				vbMetro.NativeBuffer, vertexDeclaration.VertexStride, 0);

			NativeDevice.NativeContext.InputAssembler.SetVertexBuffers(0, nativeVertexBufferBindings);

			DrawPrimitives(primitiveType, vertexOffset, primitiveCount);
		}

		#endregion // DrawUserPrimitives<T>

        #region ApplyPrimitiveType
        private void ApplyPrimitiveType(PrimitiveType primitiveType)
        {
            var d3dContext = NativeDevice.NativeContext;
            d3dContext.InputAssembler.PrimitiveTopology = FormatConverter.Translate(primitiveType);
        }
        #endregion
		
		#region CalculateVertexCount
		private int CalculateVertexCount(PrimitiveType type, int primitiveCount)
		{
			if (type == PrimitiveType.TriangleList)
				return primitiveCount * 3;
			else if (type == PrimitiveType.LineList)
				return primitiveCount * 2;
			else if (type == PrimitiveType.LineStrip)
				return primitiveCount + 1;
			else if (type == PrimitiveType.TriangleStrip)
				return primitiveCount + 2;
			else
				throw new NotImplementedException("couldn't calculate vertex count for PrimitiveType '" + type + "'");
		}
		#endregion

		#region SetIndexBuffer
		public void SetIndexBuffer(IndexBuffer indexBuffer)
		{
			if (indexBuffer == null)
				throw new ArgumentNullException("indexBuffer");

			IndexBuffer_Metro nativeIndexBuffer = indexBuffer.NativeIndexBuffer as IndexBuffer_Metro;

			if (nativeIndexBuffer != null)
			{
				NativeDevice.NativeContext.InputAssembler.SetIndexBuffer(nativeIndexBuffer.NativeBuffer,
                    FormatConverter.Translate(indexBuffer.IndexElementSize), 0);
			}
			else
			{
				throw new Exception("couldn't fetch native DirectX10 IndexBuffer");
			}
		}
		#endregion

#if XNAEXT
        public void SetConstantBuffer(int slot, ANX.Framework.Graphics.ConstantBuffer constantBuffer)
        {
            if (constantBuffer == null)
            {
                throw new ArgumentNullException("constantBuffer");
            }

            throw new NotImplementedException();
        }
#endif

		#region SetVertexBuffers
		public void SetVertexBuffers(VertexBufferBinding[] vertexBuffers)
		{
			if (vertexBuffers == null)
				throw new ArgumentNullException("vertexBuffers");

			this.currentVertexBuffer = vertexBuffers[0].VertexBuffer;   //TODO: hmmmmm, not nice :-)

			var nativeVertexBufferBindings = new Dx11.VertexBufferBinding[vertexBuffers.Length];
			for (int i = 0; i < vertexBuffers.Length; i++)
			{
				VertexBufferBinding anxVertexBufferBinding = vertexBuffers[i];
				VertexBuffer_Metro nativeVertexBuffer =
                    anxVertexBufferBinding.VertexBuffer.NativeVertexBuffer as VertexBuffer_Metro;

				if (nativeVertexBuffer != null)
				{
                    int vertexStride = anxVertexBufferBinding.VertexBuffer.VertexDeclaration.VertexStride;
					nativeVertexBufferBindings[i] = new Dx11.VertexBufferBinding(nativeVertexBuffer.NativeBuffer, vertexStride, anxVertexBufferBinding.VertexOffset * vertexStride);
				}
				else
				{
					throw new Exception("couldn't fetch native DirectX10 VertexBuffer");
				}
			}

			NativeDevice.NativeContext.InputAssembler.SetVertexBuffers(0, nativeVertexBufferBindings);
		}
		#endregion

		#region SetViewport
		public void SetViewport(Viewport viewport)
		{
			this.currentViewport = new Dx11.Viewport(viewport.X, viewport.Y,
				viewport.Width, viewport.Height, viewport.MinDepth, viewport.MaxDepth);
		}
		#endregion

        #region SetInputLayout
        private void SetInputLayout()
        {
            VertexElement[] vertexElements = currentVertexBuffer.VertexDeclaration.GetVertexElements();
            int elementCount = vertexElements.Length;
            var inputElements = new Dx11.InputElement[elementCount];

            for (int i = 0; i < elementCount; i++)
            {
                inputElements[i] = CreateInputElementFromVertexElement(vertexElements[i]);
            }

            var nativePass = currentTechnique[0];
            NativeDevice.NativeContext.InputAssembler.InputLayout =
                nativePass.BuildLayout(NativeDevice.NativeDevice, inputElements);
        }
        #endregion

        #region CreateInputElementFromVertexElement
        private Dx11.InputElement CreateInputElementFromVertexElement(VertexElement vertexElement)
		{
			string elementName = FormatConverter.Translate(vertexElement.VertexElementUsage);
			Format elementFormat = FormatConverter.Translate(vertexElement.VertexElementFormat);

			return new Dx11.InputElement(elementName, vertexElement.UsageIndex, elementFormat,
				vertexElement.Offset, 0);
		}
		#endregion

		#region SetRenderTargets (TODO)
		public void SetRenderTargets(params RenderTargetBinding[] renderTargets)
		{
			/*if (renderTargets == null)
			{
				// reset the RenderTarget to backbuffer
				if (renderTargetView != null)
				{
					renderTargetView.Dispose();
					renderTargetView = null;
				}

				//TODO: device.OutputMerger.SetRenderTargets(1, new RenderTargetView[] { this.renderView }, this.depthStencilView);
				deviceContext.OutputMerger.SetTargets(this.depthStencilView, this.renderView);
			}
			else
			{
				if (renderTargets.Length == 1)
				{
					RenderTarget2D renderTarget = renderTargets[0].RenderTarget as RenderTarget2D;
					RenderTarget2D_Metro nativeRenderTarget = renderTarget.NativeRenderTarget as RenderTarget2D_Metro;
					if (renderTarget != null)
					{
						if (renderTargetView != null)
						{
							renderTargetView.Dispose();
							renderTargetView = null;
						}
						this.renderTargetView = new RenderTargetView(deviceContext.Device, ((Texture2D_Metro)nativeRenderTarget).NativeShaderResourceView.Resource);
						DepthStencilView depthStencilView = null;
						deviceContext.OutputMerger.SetTargets(new RenderTargetView[] { this.renderTargetView });
						//deviceContext.OutputMerger.SetTargets(new RenderTargetView[] { this.renderTargetView }, depthStencilView);
						//TODO: set depthStencilView
					}
				}
				else
				{
					throw new NotImplementedException("handling of multiple RenderTargets are not yet implemented");
				}
			}*/
		}
		#endregion

		#region GetBackBufferData (TODO)
		public void GetBackBufferData<T>(Rectangle? rect, T[] data, int startIndex, int elementCount) where T : struct
		{
			throw new NotImplementedException();
		}

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

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

		#region ResizeBuffers
		public void ResizeBuffers(PresentationParameters presentationParameters)
		{
			NativeDevice.Resize(presentationParameters);
			ResizeRenderWindow(presentationParameters);
		}
		#endregion

		#region ResizeRenderWindow (TODO)
		private void ResizeRenderWindow(PresentationParameters presentationParameters)
		{
			// TODO
			//WindowsGameWindow gameWindow = (WindowsGameHost.Instance.Window as WindowsGameWindow);
			//if (gameWindow.Form != null)
			//{
				//gameWindow.Form.Bounds
			//}
		}
		#endregion

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