using System;
using System.Net;
using System.Net.Sockets;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Test_Comm_Dist
{
    // State object for data recovery from a remote device
    public class StateObject
    {
        // Socket Client
        public Socket workSocket = null;
        // Received Buffer size
        public const int BufferSize = 256;
        // Receive the buffer
        public byte[] buffer = new byte[BufferSize];
        // Receive data string
        public StringBuilder sb = new StringBuilder();

    }

    public class AsynchronousClient
    {
        // Port number for remote device
        private const int port = 11000;

        // ManualResetEvent instances report completion
        private static ManualResetEvent connectDone = new ManualResetEvent(false);
        private static ManualResetEvent sendDone = new ManualResetEvent(false);
        private static ManualResetEvent receiveDone = new ManualResetEvent(false);

        // Remote device response
        private static String response = String.Empty;

        private static void StartClient()
        {
            // Connects to the device remotely
            try
            {
                IPHostEntry ipHostInfo = Dns.GetHostEntry("192.168.56.1");
                IPAddress ipAddress = ipHostInfo.AddressList[0];
                IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);

                // Create TCP/IP Socket
                Socket client = new Socket(ipAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);

                // Connects to the remote endpoint
                client.BeginConnect(remoteEP, new AsyncCallback(ConnectCallback), client);
                connectDone.WaitOne();

                // Sends test data to the remote device
                Send(client, "This is a test<EOF>");
                sendDone.WaitOne();

                // Receive a response from the remote device
                Receive(client);
                receiveDone.WaitOne();

                // Writes the response to the console
                Console.WriteLine("Response received : {0}", response);

                // Release the socket
                client.Shutdown(SocketShutdown.Both);
                client.Close();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }

        private static void ConnectCallback(IAsyncResult ar)
        {
            try
            {
                // Get the socket of the state object
                Socket client = (Socket)ar.AsyncState;

                // End the connection
                client.EndConnect(ar);

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

                // Signal that the connection has been made
                connectDone.Set();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }
        private static void Receive(Socket client)
        {
            try
            {
                // Creating the object state
                StateObject state = new StateObject();
                state.workSocket = client;

                // Starts receiving data from remote device
                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
            {
                // Retrieve the state object and client socket from the asynchronous state object
                StateObject state = (StateObject)ar.AsyncState;
                Socket client = state.workSocket;

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

                if (bytesRead > 0)
                {
                    // Allows to store data in addition
                    state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));

                    // Gets the rest of the data
                    client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback),
                        state);
                }
                else
                {
                    // Responding all data that has arrived
                    if (state.sb.Length > 1)
                    {
                        response = state.sb.ToString();
                    }
                    // Signal that all bytes have been received
                    receiveDone.Set();
                }
            }

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

        private static void Send(Socket client, String data)
        {
            // Convert string data to byte data using ASCII encoding
            byte[] byteData = Encoding.ASCII.GetBytes(data);

            // Start sending data to the remote device
            client.BeginSend(byteData, 0, byteData.Length, 0, new AsyncCallback(SendCallBack), client);
        }

        private static void SendCallBack(IAsyncResult ar)
        {
            try
            {
                // Retrieves the sending of state object
                Socket client = (Socket)ar.AsyncState;

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

                // Signal that all bytes have been sent
                sendDone.Set();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }

        public static int Main(String[] args)
        {
            StartClient();
            return 0;
        }
    }


}