//
// Very simple server for remote access to serial ports
// serial port config is 9600bps, no parity, 8bits, 1 stop bit, no handshaking
// hklab.net/wiki/Remote_access_to_serial_port
//

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


class server_rs232
{
    private static TcpListener      server = null;
    private static TcpClient        client = null;
    private static NetworkStream    stream = null;
    private static SerialPort       serial = null;

    // Loop to read octets from serial port and send them to network
    private static void ListenSerial()
    {
        byte c;

        for(;;)
        {
            c = (byte) serial.ReadByte();
            if (client != null)
                if (client.Connected)
                {
                    stream.WriteByte(c);
                    Console.WriteLine("serial-->client {0}", c);
                }
        }
    }


    static void Main(string[] args)
    {
        if (args.Length != 2)
        {
            Console.WriteLine("Usage: server_rs232 <tcp_port> <serial_port>");
            Environment.Exit(0);
        }

        try
        {

            // serial port standart configuration 
            serial = new SerialPort(args[1]);
            serial.BaudRate = 9600;
            serial.DataBits = 8;
            serial.Parity = Parity.None;
            serial.StopBits = StopBits.One;
            serial.Handshake = Handshake.None;
            serial.Open();

            // Launch thread that reads serial port and send bytes read to the client
            Thread th = new Thread(ListenSerial);
            th.Start();

            // Start listening for client requests.
            Int16 port = Convert.ToInt16(args[0]);

            server = new TcpListener(System.Net.IPAddress.Any, port);
            server.Start();

            // Enter the listening loop
            while (true)
            {
                Console.WriteLine("Using serial port {0}", args[1]);
                Console.WriteLine("Waiting for a connection on port tcp/{0}... ", port);

                // Perform a blocking call to accept requests.
                // You could also user server.AcceptSocket() here.
                client = server.AcceptTcpClient();
                Console.WriteLine("Connected!");

                // Get a stream object for reading and writing
                stream = client.GetStream();
                
                // Loop to receive all the octets sent by the client
                byte[] c = new byte[1];

                while ((stream.Read(c, 0, 1)) != 0)
                {
                    Console.WriteLine("client-->serial {0}", c[0]);
                    serial.Write(c, 0, 1);
                }

                // Shutdown and end connection
                client.Close();
            }

        }
        catch (System.Exception e)
        {
            Console.WriteLine("Error: {0}", e.Message);
            Environment.Exit(1);
        }
        finally
        {
            // Stop listening for new clients.
            server.Stop();
            // Close serial port
            serial.Close();
            Console.WriteLine("\nFinished.");
        }
    }
}