using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Text;

// State object for receiving data from remote device.
public class StateObject
{
    // Client socket.
    public Socket workSocket = null;
    // Size of receive buffer.
    public const int BufferSize = 256;
    // Receive buffer.
    public byte[] buffer = new byte[BufferSize];
    // Received data string.
    public StringBuilder sb = new StringBuilder();
}

public class AsynchronousClient
{
    private const int port = 11000;

    private static ManualResetEvent connectDone =
        new ManualResetEvent(false);
    private static ManualResetEvent sendDone =
        new ManualResetEvent(false);
    private static ManualResetEvent receiveDone =
        new ManualResetEvent(false);

    private static String response = String.Empty;

    public static void StartClient(string message)
    {
        // Connect to a remote device.
        try
        {
            IPHostEntry ipHostInfo = Dns.GetHostEntry("my_address");
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);

            Socket client = new Socket(ipAddress.AddressFamily,
                SocketType.Stream, ProtocolType.Tcp);

            client.BeginConnect(remoteEP,
                new AsyncCallback(ConnectCallback), client);
            connectDone.WaitOne();

            // Send test data to the remote device.
            //UnityEngine.Debug.Log("Client started...");
            Send(client, message + "<EOF>");

            sendDone.WaitOne();

            Receive(client);
            receiveDone.WaitOne();

            Console.WriteLine("Response received : {0}", response);

            client.Shutdown(SocketShutdown.Both);
            client.Close();

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

    private static void ConnectCallback(IAsyncResult ar)
    {
        try
        {
            Socket client = (Socket)ar.AsyncState;

            client.EndConnect(ar);

            Console.WriteLine("Socket connected to {0}",
                client.RemoteEndPoint.ToString());

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

    private static void Receive(Socket client)
    {
        try
        {
            StateObject state = new StateObject();
            state.workSocket = client;

            client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReceiveCallback), state);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }

    private static void ReceiveCallback(IAsyncResult ar)
    {
        try
        {

            StateObject state = (StateObject)ar.AsyncState;
            Socket client = state.workSocket;

            // Read data from the remote device.
            int bytesRead = client.EndReceive(ar);

            if (bytesRead > 0)
            {
                state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));

                client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                    new AsyncCallback(ReceiveCallback), state);
            }
            else
            {

                if (state.sb.Length > 1)
                {
                    response = state.sb.ToString();
                }

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

    private static void Send(Socket client, String data)
    {

        byte[] byteData = Encoding.ASCII.GetBytes(data);

        client.BeginSend(byteData, 0, byteData.Length, 0,
            new AsyncCallback(SendCallback), client);
    }

    private static void SendCallback(IAsyncResult ar)
    {
        try
        {

            Socket client = (Socket)ar.AsyncState;


            int bytesSent = client.EndSend(ar);
            Console.WriteLine("Sent {0} bytes to server.", bytesSent);

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

    public static void Main()
    {
        while (true)
        {
            string message = Console.ReadLine();
            StartClient(message);
        }
    }
}