using SharpDX;
using SharpDX.Direct3D11;
using SharpDX.DXGI;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Valve.VR;

namespace VDash.Overlay
{
    public class WindowOverlay : DashOverlay,IDisposable
    {
        public CVRSystem VRSystem { get; private set; }
        private Task m_EventPumpTask = null;
        bool m_Created = false;
        bool m_Running = true;

        public WindowOverlay(string key, string name) : base(key, name)
        {
        }

        public void Create()
        {
            ConsoleManager.Show();
            ulong thumbHandle = OpenVR.k_ulOverlayHandleInvalid;

            //Actually create the overlay
            var overlay = OpenVR.Overlay;
            EVROverlayError err = overlay.CreateDashboardOverlay(m_Key, m_Name, ref m_Handle, ref thumbHandle);

            if (err != EVROverlayError.None)
            {
                throw new Exception($"Error creating overlay: {err}");
            }

            overlay.SetOverlayWidthInMeters(m_Handle, 2.5f);
            overlay.SetOverlayInputMethod(m_Handle, VROverlayInputMethod.Mouse);
            m_EventPumpTask = Task.Factory.StartNew(() => { EventPump(); });
            m_Created = true;
        }

        private void EventPump()
        {
            #region Rendering setup
            var overlay = OpenVR.Overlay;

            //Skip rendering if overlay isn't visible
            if ((m_Handle == OpenVR.k_ulOverlayHandleInvalid) || overlay == null || (!overlay.IsOverlayVisible(m_Handle)))
            {
                //return;
            }

            //Taken from here: https://stackoverflow.com/questions/6812068/c-sharp-which-is-the-fastest-way-to-take-a-screen-shot

            var factory = new Factory1();
            //Get first adapter
            var adapter = factory.GetAdapter1(0);
            //Get device from adapter
            var device = new SharpDX.Direct3D11.Device(adapter);

            #endregion
            int frames = 0;
            DateTime lastFps = DateTime.MinValue;

            while (m_Running)
            {
                #region VR Events
                VREvent_t vrEvent = new VREvent_t();

                while (OpenVR.Overlay.PollNextOverlayEvent(m_Handle, ref vrEvent, (uint)Marshal.SizeOf(vrEvent)))
                {
                    switch ((EVREventType)vrEvent.eventType)
                    {
                        case EVREventType.VREvent_MouseMove:
                            {
                                var x = vrEvent.data.mouse.x;
                                var y = vrEvent.data.mouse.y;
                                break;
                            }

                        case EVREventType.VREvent_MouseButtonDown:
                            {
                                var clickType = (EVRMouseButton)vrEvent.data.mouse.button;
                                break;
                            }

                        case EVREventType.VREvent_MouseButtonUp:
                            {
                                var clickType = (EVRMouseButton)vrEvent.data.mouse.button;
                                break;
                            }
                        case EVREventType.VREvent_OverlayShown:
                            {
                                Console.WriteLine("Overlay Shown!");
                                break;
                            }
                    }

                }
                #endregion

                #region Acutally Render

                var proc = Process.GetProcessesByName("discord")[1];
                var rect = new User32.Rect();
                User32.GetWindowRect(proc.MainWindowHandle, ref rect);

                int width = rect.right - rect.left;
                int height = rect.bottom - rect.top;

                using (var bmp = new Bitmap(width, height, PixelFormat.Format32bppArgb))
                {
                    using (Graphics graphics = Graphics.FromImage(bmp))
                    {
                        graphics.CopyFromScreen(rect.left, rect.top, 0, 0, new Size(width, height), CopyPixelOperation.SourceCopy);

                        var data = bmp.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);

                        // Create Staging texture CPU-accessible
                        var textureDesc = new Texture2DDescription
                        {
                            CpuAccessFlags = CpuAccessFlags.Read,
                            BindFlags = BindFlags.None,
                            Format = Format.B8G8R8A8_UNorm,
                            Width = width,
                            Height = height,
                            OptionFlags = ResourceOptionFlags.None,
                            MipLevels = 1,
                            ArraySize = 1,
                            SampleDescription = { Count = 1, Quality = 0 },
                            Usage = ResourceUsage.Staging
                        };

                        using (var screenTexture = new Texture2D(device, textureDesc, new SharpDX.DataRectangle(data.Scan0, data.Stride)))
                        //using (var screenTexture = new Texture2D(device, textureDesc))
                        {
                            var texture = new Texture_t();
                            texture.handle = screenTexture.NativePointer;
                            texture.eType = ETextureType.DirectX;
                            texture.eColorSpace = EColorSpace.Auto;
                            EVROverlayError result = overlay.SetOverlayTexture(m_Handle, ref texture);
                            if (result != EVROverlayError.None)
                            {
                                Console.WriteLine($"Error rendering: {result}");
                            }

                            frames++;

                            bmp.UnlockBits(data);
                        }
                        //Dispose not freeing screenTexture: https://gamedev.stackexchange.com/questions/93311/freeing-texture-memory-in-sharpdx-what-am-i-missing
                        device.ImmediateContext.ClearState();
                        device.ImmediateContext.Flush();
                    }
                }
                #endregion

                Thread.Sleep(10);

                if (DateTime.Now.Subtract(lastFps).TotalMilliseconds > 1000)
                {
                    Console.WriteLine($"{frames} fps.");
                    frames = 0;
                    lastFps = DateTime.Now;
                }
            }
        }

        private class User32
        {
            [StructLayout(LayoutKind.Sequential)]
            public struct Rect
            {
                public int left;
                public int top;
                public int right;
                public int bottom;
            }

            [DllImport("user32.dll")]
            public static extern IntPtr GetWindowRect(IntPtr hWnd, ref Rect rect);
        }

        public void Dispose()
        {
            //FIXME: Actually implement this...
        }
    }
}