using Accord.Video.FFMPEG;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace ScreenBroadcast
{
    internal class Program
    {
        //[DllImport("user32.dll", SetLastError = true)]
        //static extern bool GetWindowRect(int hWnd, out RECT lpRect);
        // For Windows Mobile, replace user32.dll with coredll.dll

        [DllImport("user32.dll", SetLastError = true)]
        private static extern int FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll", SetLastError = true)]
        private static extern bool GetClientRect(int hWnd, out Rect lpRect);

        [DllImport("user32.dll")]
        private static extern bool ClientToScreen(int hWnd, ref Point lpPoint);

        [StructLayout(LayoutKind.Sequential)]
        public struct Rect
        {
            public int Left;
            public int Top;
            public int Right;
            public int Bottom;

            public int Height => Bottom - Top;
            public int Width => Right - Left;

            public Size Size => new Size(Width, Height);
            public Point Location => new Point(Left, Top);
        }

        private static void Main()
        {
            //comfig var
            string wndCls = "ConsoleWindowClass";
            string wndName = "管理员: 命令提示符";
            int port = 2333;

            var frameRate = 25;

            var broadcastQuality = 20L;

            //runtime var
            var runing = true;
            int clientNum = 0;
            byte[] buf = null;
            var waits = new List<AutoResetEvent>();

            var taskSource = Task.Factory.StartNew(() =>
            {
                //image encoding params
                var format = ImageFormat.Jpeg;

                var codec = ImageCodecInfo.GetImageDecoders().First(p => p.FormatID == format.Guid);
                var codecParam = new EncoderParameters(1);

                //buffer vars
                Bitmap imgBuf = null;
                var vdoWriter = new VideoFileWriter();
                var ms = new MemoryStream();

                var hWnd = 0;
                try
                {
                    while (runing)
                    {
                        if (hWnd == 0) hWnd = FindWindow(wndCls, wndName);

                        Rect rectWndCa;
                        var ptWndLoc = Point.Empty;

                        if (GetClientRect(hWnd, out rectWndCa) && ClientToScreen(hWnd, ref ptWndLoc))
                        {
                            Func<int, int> ensureBy2 = v => v % 2 != 0 ? v + 1 : v;
                            Func<int, int> ensureBy4 = v => v % 4 != 0 ? v + (4 - v % 4) : v;
                            Func<int, int, int> ensureBy = (b, v) => v % b != 0 ? v + (b - v % b) : v;

                            var rect = new Rectangle(ptWndLoc, new Size(ensureBy(2, rectWndCa.Size.Width), ensureBy(2, rectWndCa.Height)));

                            if (imgBuf == null || imgBuf.Size != rect.Size)
                            {
                                imgBuf = new Bitmap(rect.Width, rect.Height, PixelFormat.Format24bppRgb);

                                if (vdoWriter.IsOpen)
                                    vdoWriter.Close();

                                var recordPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "record");
                                Directory.CreateDirectory(recordPath);

                                var filename = $"record_{DateTime.Now:yyyyMMdd_HHmmss_fffff}-{rect.Width:0000}-{rect.Height:0000}.avi";

                                vdoWriter.Open(Path.Combine(recordPath, filename), rect.Width, rect.Height, frameRate, VideoCodec.MPEG4, 8000000);
                            }

                            Graphics srcGraphics = Graphics.FromImage(imgBuf);
                            srcGraphics.CopyFromScreen(rect.Location, Point.Empty, rect.Size);

                            codecParam.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, broadcastQuality);

                            ms.SetLength(0);
                            imgBuf.Save(ms, codec, codecParam);
                            //imgBuf.Save(ms, format);
                            buf = ms.ToArray();

                            foreach (var item in waits)
                            {
                                item.Set();
                            }

                            vdoWriter.WriteVideoFrame(imgBuf);
                        }
                        else
                        {
                            hWnd = 0; //re find win
                            Console.WriteLine("waiting window found...");
                        }

                        Thread.Sleep(1000 / frameRate);
                    }

                    vdoWriter.Close();
                }
                catch (Exception ex)
                {
                    throw;
                }
            });

            Task.Factory.StartNew(() =>
            {
                Socket Server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                Server.Bind(new IPEndPoint(IPAddress.Any, port));
                Server.Listen(10);

                Console.WriteLine("Listening...");

                while (runing)
                {
                    int num;
                    var client = Server.Accept();
                    Console.WriteLine("Acceped socket #{0} from {1} onlines {2}", num = ++clientNum, client.RemoteEndPoint, waits.Count);

                    Task.Factory.StartNew(() =>
                    {
                        var wait = new AutoResetEvent(false);
                        waits.Add(wait);

                        try
                        {
                            var stream = new NetworkStream(client, true);
                            var writer = new BinaryWriter(stream);

                            writer.Write(Encoding.ASCII.GetBytes("HTTP / 1.1 200 OK\r\n"));
                            writer.Write(Encoding.ASCII.GetBytes("Content-Type: multipart/x-mixed-replace; boundary=frame\r\n"));

                            while (runing)
                            {
                                wait.WaitOne();
                                var rbuf = buf;
                                if (rbuf != null)
                                {
                                    writer.Write(Encoding.ASCII.GetBytes("\r\n"));
                                    writer.Write(Encoding.ASCII.GetBytes("--frame\r\n"));
                                    writer.Write(Encoding.ASCII.GetBytes("Content-Type: image/png\r\n"));
                                    writer.Write(Encoding.ASCII.GetBytes("Content-Length: " + rbuf.Length + "\r\n"));
                                    writer.Write(Encoding.ASCII.GetBytes("\r\n"));
                                    writer.Write(rbuf);
                                }
                            }
                        }
                        catch (Exception ex)
                        {
                            Console.WriteLine("Lost socket #{1} from {0} onlines {2} by {3}", client.RemoteEndPoint, num, waits.Count, ex.Message);
                        }

                        waits.Remove(wait);
                    });
                }
            });

            ConsoleKeyInfo k;
            while (char.ToLower((k = Console.ReadKey(true)).KeyChar) != 'q')
            {
                if (k.Key == ConsoleKey.UpArrow)
                {
                    if (broadcastQuality + 1 == 0)
                        broadcastQuality += 2;
                    else
                        broadcastQuality += 1;

                    Console.WriteLine("Quality: {0}", broadcastQuality);
                }
                else if (k.Key == ConsoleKey.DownArrow)
                {
                    if (broadcastQuality - 1 == 0)
                        broadcastQuality -= 2;
                    else
                        broadcastQuality -= 1;

                    Console.WriteLine("Quality: {0}", broadcastQuality);
                }
                else
                {
                    Console.WriteLine("Press Q to exit. up-arrow to inc quality, down-arrow to dec");
                }
            }

            runing = false;

            taskSource.Wait();
        }
    }
}