using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Concurrent;

// State object for reading client data asynchronously
public class StateObject
{
    // Client  socket.
    public Socket workSocket = null;
    // Size of receive buffer.
    public const int BufferSize = 1024;
    // Receive buffer.
    public byte[] buffer = new byte[BufferSize];
    // Received data string.
    public StringBuilder sb = new StringBuilder();

    public string command;

    public int userID;
    public int SystemID;
    public decimal xfrom;
    public decimal yfrom;
    public decimal xto;
    public decimal yto;
    public string UserName;
    public string ShipName;

}


public class AsynchronousSocketListener
{
  //  public static ArrayList Clients = new ArrayList();
    public static ConcurrentDictionary<int, StateObject> Clients = new ConcurrentDictionary<int, StateObject>(6, 1000);

    // Thread signal.
    public static ManualResetEvent allDone = new ManualResetEvent(false);

    public AsynchronousSocketListener()

    {

    }

    public static bool IsConnected(Socket socket)
    {
        try
        {
            return !(socket.Poll(1, SelectMode.SelectRead) && socket.Available == 0);
        }
        catch (SocketException) { return false; }
    }

    public static void StartListening()
    {
        // Data buffer for incoming data.
        byte[] bytes = new Byte[1024];

        // Establish the local endpoint for the socket.
        // The DNS name of the computer
        // running the listener is "host.contoso.com".
        IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
        IPAddress ipAddress = ipHostInfo.AddressList[0];
        IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 4444);

        // Create a TCP/IP socket.
        Socket listener = new Socket(AddressFamily.InterNetwork,
        SocketType.Stream, ProtocolType.Tcp);

        // Bind the socket to the local endpoint and listen for incoming connections.
        try
        {
            listener.Bind(localEndPoint);
            listener.Listen(100);


            while (true)
            {
                // Set the event to nonsignaled state.
                allDone.Reset();

                // Start an asynchronous socket to listen for connections.
                //Console.WriteLine("Listening...");

                listener.BeginAccept(new AsyncCallback(AcceptCallback),listener);

                // Wait until a connection is made before continuing.
                allDone.WaitOne();
            }

        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }

        Console.WriteLine("\nPress ENTER to continue...");
        Console.Read();

    }

    public static void AcceptCallback(IAsyncResult ar)
    {
        // Signal the main thread to continue.
        allDone.Set();

        // Get the socket that handles the client request.
        Socket listener = (Socket)ar.AsyncState;
        Socket handler = listener.EndAccept(ar);

        StateObject client = new StateObject();

        client.workSocket = handler;
        handler.BeginReceive(client.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallback), client);
    }

    public static void ReadCallback(IAsyncResult ar)
    {

        String content = String.Empty;
        ArrayList NewClients = new ArrayList();
        // Retrieve the state object and the handler socket
        // from the asynchronous state object.
        StateObject state = (StateObject)ar.AsyncState;
        Socket handler = state.workSocket;

        // Read data from the client socket.
        int bytesRead = handler.EndReceive(ar);
        string[] Data;
        string Message = "";


        if (bytesRead > 0)
        {
            // There  might be more data, so store the data received so far.
            state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));
            Console.WriteLine(state.sb.ToString());
            // Check for end-of-file tag. If it is not there, read
            // more data.


            content = state.sb.ToString();

            //deal with policy
            if (content.Substring(0, 22) == "<policy-file-request/>")
            {
                Message = "<?xml version=\"1.0\"?> " +
                          "<!DOCTYPE cross-domain-policy SYSTEM " +
                          "    \"http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd\"> " +
                          "<cross-domain-policy>" +
                          "   <allow-access-from domain=\"*\" to-ports=\"4444\"/>" +
                          "</cross-domain-policy>\0";

                Send(state.workSocket, Message, -1);

            }


            if (content.IndexOf("<EOF>") > -1)
            {
                Data = content.Split('|');
                //Decide on the command sent:

                //0000 - initial connection
                if (Data[0] == "0000") {
                    //add the client to the dictionary of clients using userID as the key
                    state.userID = Convert.ToInt32(Data[1]);
                    state.SystemID = Convert.ToInt32(Data[2]);
                    state.xfrom = Convert.ToDecimal(Data[3]);
                    state.yfrom = Convert.ToDecimal(Data[4]);
                    state.xto = Convert.ToDecimal(Data[5]);
                    state.yto = Convert.ToDecimal(Data[6]);
                    state.UserName = Data[7];
                    state.ShipName = Data[8];

                    Clients.TryAdd(state.userID, state);

                    Message = "0000|" + "CONNECTED";
                    Send(state.workSocket, Message, state.userID);
                    Console.WriteLine("Client Connected, User : " + state.UserName);
                }

                if (Data[0] == "0002")
                  {
                      state.userID = Convert.ToInt32(Data[1]);
                      state.SystemID = Convert.ToInt32(Data[2]);
                      state.xfrom = Convert.ToDecimal(Data[3]);
                      state.yfrom = Convert.ToDecimal(Data[4]);
                      state.xto = Convert.ToDecimal(Data[5]);
                      state.yto = Convert.ToDecimal(Data[6]);

                    foreach (var pair in Clients)
                        {

                            if (pair.Value.SystemID == state.SystemID && pair.Value.userID != state.userID)
                            {

                                Message = "0002|" + state.userID.ToString() + "|" + state.xfrom.ToString() + "|" + state.yfrom.ToString() + "|" + state.xto.ToString() + "|" + state.yto.ToString() + "|" + state.UserName.ToString() + "|" + state.ShipName.ToString();

                                Send(pair.Value.workSocket, Message, pair.Value.userID);
                                Console.WriteLine("Data Sent to : " + pair.Value.userID.ToString() + " Message : " + Message.ToString());

                                Message = "0002|" + pair.Value.userID.ToString() + "|" + pair.Value.xfrom.ToString() + "|" + pair.Value.yfrom.ToString() + "|" + pair.Value.xto.ToString() + "|" + pair.Value.yto.ToString() + "|" + pair.Value.UserName.ToString() + "|" + pair.Value.ShipName.ToString();
                                Send(state.workSocket, Message, state.userID);
                                Console.WriteLine("Data Sent to : " + state.userID.ToString() + " Message : " + Message.ToString());
                            }
                        }
                }


            }
            else
            {
                // Not all data received. Get more.
                handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReadCallback), state);
            }
        }
    }

    private static void Send(Socket handler, string data, int userID)
    {
        try
        {
            // Convert the string data to byte data using ASCII encoding.
            byte[] byteData = Encoding.ASCII.GetBytes(data);

            // Begin sending the data to the remote device.
            handler.BeginSend(byteData, 0, byteData.Length, 0,new AsyncCallback(SendCallback), handler);
        }
        catch (Exception e)
        {
            StateObject RemovedClient = new StateObject();
            Clients.TryRemove(userID, out RemovedClient);
            Console.WriteLine("Removed Client, User : " + RemovedClient.UserName);
            handler.Close();

        }

    }

    private static void SendCallback(IAsyncResult ar)
    {
        try
        {

            // Retrieve the socket from the state object.
            Socket handler = (Socket)ar.AsyncState;


            // Complete sending the data to the remote device.
            int bytesSent = handler.EndSend(ar);
            Console.WriteLine("Sent {0} bytes to client.", bytesSent);

            //handler.Shutdown(SocketShutdown.Both);
            //handler.Close();
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString() + "SendCallBack");
        }
    }


        public static int Main(String[] args)
    {


        StartListening();
        return 0;

    }
}