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

namespace MarcoPoloClient
{
    public class SocketClient
    {
        Socket _socket = null;
        static ManualResetEvent _clientDone = new ManualResetEvent (false);
        const int TIMEOUT_MILLISECONDS = 5000;
        const int MAX_BUFFER_SIZE = 2048;

        public SocketClient ()
        {
        }

        public string Connect (string hostName, int portNumber)
        {
            string result = string.Empty;
            DnsEndPoint hostEntry = new DnsEndPoint (hostName, portNumber);
            _socket = new Socket (
                AddressFamily.InterNetwork,
                SocketType.Stream,
                ProtocolType.Tcp
            );
            SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs ();
            socketEventArg.RemoteEndPoint = hostEntry;

            socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs> (delegate(object s, SocketAsyncEventArgs e)
                {
                    result = e.SocketError.ToString ();
                    _clientDone.Set ();
                }
            );

            _clientDone.Reset ();
            _socket.ConnectAsync (socketEventArg);
            _clientDone.WaitOne (TIMEOUT_MILLISECONDS);

            return result;
        }

        public string Send (string data)
        {
            string response = "Operation Timeout";

            if (_socket != null) {
                SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs ();
                socketEventArg.RemoteEndPoint = _socket.RemoteEndPoint;
                socketEventArg.UserToken = null;

                socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs> (delegate(object s, SocketAsyncEventArgs e)
                    {
                        response = e.SocketError.ToString ();
                        _clientDone.Set ();
                    }
                );

                byte[] payload = Encoding.UTF8.GetBytes (data);
                socketEventArg.SetBuffer (payload, 0, payload.Length);

                _clientDone.Reset ();
                _socket.SendAsync (socketEventArg);
                _clientDone.WaitOne (TIMEOUT_MILLISECONDS);
            } else {
                response = "Socket is not initialized";
            }
            return response;
        }

        public string Receive ()
        {
            string response = "Operation Timeout";

            if (_socket != null) {
                SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs ();
                socketEventArg.RemoteEndPoint = _socket.RemoteEndPoint;

                socketEventArg.SetBuffer (new Byte[MAX_BUFFER_SIZE], 0, MAX_BUFFER_SIZE);
                socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs> (delegate(object s, SocketAsyncEventArgs e)
                    {
                        if (e.SocketError == SocketError.Success) {
                            response = Encoding.UTF8.GetString (e.Buffer, e.Offset, e.BytesTransferred);
                            response = response.Trim ('\0');
                        } else {
                            response = e.SocketError.ToString ();
                        }
                        _clientDone.Set ();
                    }
                );

                _clientDone.Reset ();
                _socket.ReceiveAsync (socketEventArg);
                _clientDone.WaitOne (TIMEOUT_MILLISECONDS);
            } else {
                response = "Socket is not initialized";
            }

            return response;
        }

        public void Close ()
        {
            if (_socket != null) {
                _socket.Close ();
            }
        }
    }
}