using System;
using System.Runtime.InteropServices;
using Windows.Graphics.DirectX.Direct3D11;
using SharpDX.Direct3D11;
using SharpDX.DXGI;

namespace ClipForge
{
    public static class Direct3D11Helper
    {
        [ComImport]
        [Guid("A9B3D012-3DF2-4EE3-B8D1-8695F457D3C1")]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        [ComVisible(true)]
        interface IDirect3DDxgiInterfaceAccess
        {
            IntPtr GetInterface([In] ref Guid iid);
        }

        [DllImport("d3d11.dll", EntryPoint = "D3D11CreateDevice",
            SetLastError = true,
            CharSet = CharSet.Unicode,
            ExactSpelling = true,
            CallingConvention = CallingConvention.StdCall)]
        private static extern int D3D11CreateDevice(
            IntPtr pAdapter,
            uint driverType,
            IntPtr software,
            uint flags,
            IntPtr pFeatureLevels,
            uint featureLevels,
            uint sdkVersion,
            out IntPtr ppDevice,
            out uint pFeatureLevel,
            out IntPtr ppImmediateContext);

        public static IDirect3DDevice CreateDevice()
        {
            // Create a SharpDX D3D11 device
            var d3dDevice = new SharpDX.Direct3D11.Device(
                SharpDX.Direct3D.DriverType.Hardware,
                DeviceCreationFlags.BgraSupport);

            // Get the DXGI device interface from it
            var dxgiDevice = d3dDevice.QueryInterface<SharpDX.DXGI.Device>();

            // Create a WinRT IDirect3DDevice from the DXGI device
            var result = CreateDirect3DDeviceFromDXGIDevice(dxgiDevice.NativePointer);

            var winrtDevice = (IDirect3DDevice)Marshal.GetObjectForIUnknown(result);
            Marshal.Release(result);
            return winrtDevice;
        }

        [DllImport("d3d11.dll",
            EntryPoint = "CreateDirect3D11DeviceFromDXGIDevice",
            SetLastError = true,
            CharSet = CharSet.Unicode,
            ExactSpelling = true,
            CallingConvention = CallingConvention.StdCall)]
        private static extern int CreateDirect3D11DeviceFromDXGIDevice(
            IntPtr dxgiDevice,
            out IntPtr graphicsDevice);

        private static IntPtr CreateDirect3DDeviceFromDXGIDevice(IntPtr dxgiDevice)
        {
            CreateDirect3D11DeviceFromDXGIDevice(dxgiDevice, out IntPtr graphicsDevice);
            return graphicsDevice;
        }
    }
}