#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

using Dx11 = SharpDX.Direct3D11;

namespace ANX.RenderSystem.Windows.DX11
{
    public partial class DxIndexBuffer : INativeIndexBuffer, IDisposable
    {
        public Dx11.Buffer NativeBuffer { get; protected set; }

        #region Constructor
        public DxIndexBuffer(GraphicsDevice graphics, IndexElementSize size, int indexCount, BufferUsage usage)
        {
            elementSize = size;
            GraphicsDeviceDX gd11 = graphics.NativeDevice as GraphicsDeviceDX;
            Dx11.DeviceContext context = gd11 != null ? gd11.NativeDevice as Dx11.DeviceContext : null;

            InitializeBuffer(context.Device, size, indexCount, usage);
        }

        internal DxIndexBuffer(SharpDX.Direct3D11.Device device, IndexElementSize size, int indexCount, BufferUsage usage)
        {
            elementSize = size;
            InitializeBuffer(device, size, indexCount, usage);
        }
        #endregion

        #region InitializeBuffer
        private void InitializeBuffer(Dx11.Device device, IndexElementSize size, int indexCount, BufferUsage usage)
        {
            //TODO: translate and use usage
            var description = new Dx11.BufferDescription()
            {
                // TODO: translate usage
                Usage = Dx11.ResourceUsage.Dynamic,
                SizeInBytes = GetSizeInBytes(indexCount),
                BindFlags = Dx11.BindFlags.IndexBuffer,
                CpuAccessFlags = Dx11.CpuAccessFlags.Write,
                OptionFlags = Dx11.ResourceOptionFlags.None
            };

            NativeBuffer = new SharpDX.Direct3D11.Buffer(device, description);
        }
        #endregion

        protected DataStream MapBufferWrite()
        {
            Dx11.DeviceContext context = NativeBuffer.Device.ImmediateContext;
            DataStream stream;
            context.MapSubresource(NativeBuffer, Dx11.MapMode.WriteDiscard, Dx11.MapFlags.None, out stream);
            return stream;
        }

        protected void UnmapBuffer()
        {
            Dx11.DeviceContext context = NativeBuffer.Device.ImmediateContext;
            context.UnmapSubresource(NativeBuffer, 0);
        }

        private SharpDX.DataStream MapBufferRead(Dx11.Buffer buffer)
        {
            Dx11.DeviceContext context = buffer.Device.ImmediateContext;
            DataStream stream;
            context.MapSubresource(buffer, Dx11.MapMode.Read, Dx11.MapFlags.None, out stream);
            return stream;
        }

        private void UnmapBuffer(Dx11.Buffer buffer)
        {
            Dx11.DeviceContext context = buffer.Device.ImmediateContext;
            context.UnmapSubresource(buffer, 0);
        }

        private void CopySubresource(Dx11.Buffer source, Dx11.Buffer destination)
        {
            BufferHelper.ValidateCopyResource(source, destination);

            this.NativeBuffer.Device.ImmediateContext.CopyResource(source, destination);
        }

        private Dx11.Buffer CreateStagingBuffer()
        {
            var description = new Dx11.BufferDescription()
            {
                Usage = Dx11.ResourceUsage.Staging,
                SizeInBytes = NativeBuffer.Description.SizeInBytes,
                CpuAccessFlags = Dx11.CpuAccessFlags.Read,
                OptionFlags = Dx11.ResourceOptionFlags.None,
            };

            return new Dx11.Buffer(NativeBuffer.Device, description);
        }
    }
}