using System;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.Threading;
using System.Security.Cryptography;
using System.IO;
using System.Diagnostics;

namespace WindowsService1
{
    public class UdpMulticast
    {
        private Socket s;
        private Thread listenThread;
        private string mcastGroup;
        private int port;
        private bool working = false;
        private bool useThreadPool = false;

        public UdpMulticast(string mcastGroup, int port)
        {
            this.mcastGroup = mcastGroup;
            this.port = port;            
        }

        private void Listen_pool(object a)
        {
            Listen();
            
        }


        private void Listen()
        {
            while (working)
            {
                try
                {
                    int recv = 0; ;
                    byte[] b = new byte[1024];
                    Thread.Sleep(1);
                    if (s != null)
                        recv = s.Receive(b);
                    else
                        break;//break if socket == null
                    if (recv == 0)
                        continue;//continue if return nr bytes == 0

                    if (OnNewDataRecv != null)
                    {
                        byte[] tmp = new byte[recv];
                        for (int i = 0; i < recv; i++)
                        {
                            tmp[i] = b[i];
                        }
                        byte[] decByte = Encryption.Decrypt(tmp);
                        if (this.OnNewDataRecv != null)
                            this.OnNewDataRecv(decByte, decByte.Length);
                    }

                    if (s == null)
                    {
                        break;
                    }
                }
                catch (SocketException ex)
                {
                    Utils.WriteEventLog("Safemobile", "UdpMulticast Listen SOCKET EXCEPTION " + ex.ToString(), EventLogEntryType.Error, 23456);
                    break;
                }
                catch (ThreadAbortException ex)
                {
                    Utils.WriteEventLog("Safemobile", "UdpMulticast Listen Thread Abort EXCEPTION " + ex.ToString(), EventLogEntryType.Error, 23456);
                    break;
                }
                catch (Exception ex)
                {
                    Utils.WriteEventLog("Safemobile", "UdpMulticast Listen Exception" + ex.ToString(), EventLogEntryType.Error, 23456);
                }
            }
        }


        public delegate void newData4Send(byte[] data, int dataLen);
        public event newData4Send OnNewDataRecv;

        public bool StartListen(string localIP = null)
        {
            bool ret = false;
            working = true;
            try
            {
                IPAddress myIP = !string.IsNullOrWhiteSpace(localIP) ? IPAddress.Parse(localIP) : getPreferedIPAdress();

                if (s == null)
                {
                    s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                }
                if (s != null)
                {
                    Utils.WriteEventLog("Safemobile", "PORT multi cast :" + port, EventLogEntryType.Information, 34500);                    
                    IPEndPoint ipep = new IPEndPoint(IPAddress.Any, port);
                    s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, 1);
                    s.Bind(ipep);
                    IPAddress ip = IPAddress.Parse(mcastGroup);
                    s.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(ip, IPAddress.Any));
                    s.SetSocketOption(SocketOptionLevel.IP,
                            SocketOptionName.MulticastTimeToLive, int.Parse("1"));
                    listenThread = new Thread(new ThreadStart(Listen));
                    listenThread.IsBackground = true;
                }
                if (listenThread != null)
                    listenThread.Start();
                ret = true;

                Utils.WriteEventLog("Safemobile", 
                    $"++++++++++++++++++++++++++++++++++++++++++\nUdpMulticast bind on {mcastGroup}:{port} Ethernet: {myIP}\n++++++++++++++++++++++++++++++++++++++++++",
                    EventLogEntryType.Information, 23456);

            }
            catch (Exception ex)
            {
                Utils.WriteEventLog("Safemobile", "Ex:" + ex.ToString(), EventLogEntryType.Error, 23456);
            }
            return ret;
        }


        public static IPAddress getPreferedIPAdress()
        {
            IPAddress localIP = IPAddress.Parse("127.0.0.1");
            Socket socket = null;
            try
            {
                using (socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, 0))
                {
                    socket.Connect("10.0.2.4", 65530);
                    IPEndPoint endPoint = socket.LocalEndPoint as IPEndPoint;
                    localIP = endPoint.Address;
                }
            }
            catch (Exception ex)
            {
                Utils.WriteLine(ex.ToString(), ConsoleColor.DarkRed);
            }
            finally
            {
                if (socket != null)
                    socket.Dispose();
            }
            return localIP;
        }


        public void Send(byte[] data, int len)
        {
            if (s == null)
            {
                s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            }

            if (s != null)
            {
                IPEndPoint ipep = new IPEndPoint(IPAddress.Parse(mcastGroup), port);
                byte[] encByte = Encryption.Encrypt(data);
                s.SendTo(encByte, encByte.Length, SocketFlags.None, ipep);
            }
            else Utils.WriteEventLog("Safemobile", "s is NULL", EventLogEntryType.Error, 23456);
        }

        public void Send_decoded(byte[] data, int len)
        {
            if (s == null)
            {
                s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            }

            if (s != null)
            {
                IPEndPoint ipep = new IPEndPoint(IPAddress.Parse(mcastGroup), port);
                s.SendTo(data, data.Length, SocketFlags.None, ipep);
            }
            else Utils.WriteEventLog("Safemobile", "s is NULL", EventLogEntryType.Error, 23456);
        }
    }

    static public class Encryption
    {
        static byte[] bytes = ASCIIEncoding.ASCII.GetBytes("SafeMobi"); //DES 64bit !

        static public byte[] Encrypt(byte[] inputArray)
        {
            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            MemoryStream memoryStream = new MemoryStream();
            CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoProvider.CreateEncryptor(bytes, bytes), CryptoStreamMode.Write);

            cryptoStream.Write(inputArray, 0, inputArray.Length);

            cryptoStream.Close(); memoryStream.Close();
            return memoryStream.ToArray();
        }

        static public byte[] Decrypt(byte[] DataToDecrypt)
        {
            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            MemoryStream memoryStream = new MemoryStream();
            CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoProvider.CreateDecryptor(bytes, bytes), CryptoStreamMode.Write);

            cryptoStream.Write(DataToDecrypt, 0, DataToDecrypt.Length);
            cryptoStream.Close(); memoryStream.Close();
            return memoryStream.ToArray();
        }
    }
}