#region Using Statements
using System;
using ANX.Framework.Graphics;
using ANX.Framework.NonXNA.RenderSystem;
using SharpDX;

#endregion

// 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

#if DX10
using Dx = SharpDX.Direct3D10;
using DxDevice = SharpDX.Direct3D10.Device;

namespace ANX.RenderSystem.Windows.DX10
#endif
#if DX11
using Dx = SharpDX.Direct3D11;
using DxDevice = SharpDX.Direct3D11.Device;

namespace ANX.RenderSystem.Windows.DX11
#endif
{
    public partial class DxVertexBuffer : INativeVertexBuffer, IDisposable
    {
        public Dx.Buffer NativeBuffer { get; protected set; }
        private Dx.DeviceContext context;

        #region Constructor
        public DxVertexBuffer(GraphicsDevice graphics, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
        {
            var gd11 = graphics.NativeDevice as GraphicsDeviceDX;
            this.context = gd11 != null ? gd11.NativeDevice as Dx.DeviceContext : null;

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

        internal DxVertexBuffer(Dx.Device device, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
        {
            InitializeBuffer(device, vertexDeclaration, vertexCount, usage);
        }
        #endregion

        #region InitializeBuffer (TODO)
        private void InitializeBuffer(Dx.Device device, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage usage)
        {
            vertexStride = vertexDeclaration.VertexStride;

            //TODO: translate and use usage

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

                NativeBuffer = new Dx.Buffer(device, description);
            }
        }
        #endregion

        private SharpDX.DataStream MapBufferWrite()
        {
            Dx.DeviceContext context = NativeBuffer.Device.ImmediateContext;
            DataStream stream;
            context.MapSubresource(NativeBuffer, Dx.MapMode.WriteDiscard, Dx.MapFlags.None, out stream);
            return stream;
        }

        private SharpDX.DataStream MapBufferRead(Dx.Resource buffer)
        {
            DataStream stream;
            buffer.Device.ImmediateContext.MapSubresource(buffer, 0, Dx.MapMode.Read, Dx.MapFlags.None, out stream);
            return stream;
        }

        private void UnmapBuffer()
        {
            Dx.DeviceContext context = NativeBuffer.Device.ImmediateContext;
            context.UnmapSubresource(NativeBuffer, 0);
        }

        private void CopySubresource(Dx.Buffer source, Dx.Buffer destination)
        {
            BufferHelper.ValidateCopyResource(source, destination);

            this.context.CopyResource(source, destination);
        }

        private void UnmapBuffer(Dx.Resource buffer)
        {
            buffer.Device.ImmediateContext.UnmapSubresource(buffer, 0);
        }

        private Dx.Buffer CreateStagingBuffer()
        {
            var description = new Dx.BufferDescription()
            {
                Usage = Dx.ResourceUsage.Staging,
                SizeInBytes = NativeBuffer.Description.SizeInBytes,
                BindFlags = Dx.BindFlags.VertexBuffer,
                CpuAccessFlags = Dx.CpuAccessFlags.Read,
                OptionFlags = Dx.ResourceOptionFlags.None
            };

            return new Dx.Buffer(context.Device, description);
        }
    }
}