/*
 * Java Network Programming, Second Edition
 * Merlin Hughes, Michael Shoffner, Derek Hamner
 * Manning Publications Company; ISBN 188477749X
 *
 * http://nitric.com/jnp/
 *
 * Copyright (c) 1997-1999 Merlin Hughes, Michael Shoffner, Derek Hamner;
 * all rights reserved; see license.txt for details.
 */

import java.io.*;
import java.net.*;

public class NBServer {
  static InputStream in0, in1;
  static OutputStream out0, out1;
  
  public static void main (String[] args) throws IOException {
    if (args.length != 1)
      throw new IllegalArgumentException ("Syntax: NBServer <port>");
    try {
      accept (Integer.parseInt (args[0]));
      int x0, x1;
      while (((x0 = readNB (in0)) != -1) &&
             ((x1 = readNB (in1)) != -1)) {
        if (x0 >= 0)
          out1.write (x0);
        if (x1 >= 0)
          out0.write (x1);
      }
    } finally {
      System.out.println ("Closing");
      close (out0);
      close (out1);
    }
  }

  static void close (OutputStream out) {
    if (out != null) {
      try {
        out.close ();
      } catch (IOException ignored) {
      }
    }
  }

  static void accept (int port) throws IOException {
    System.out.println ("Starting on port " + port);
    ServerSocket server = new ServerSocket (port);
    try {
      System.out.println ("Waiting..");
      Socket client0 = server.accept ();
      System.out.println ("Accepted from " + client0.getInetAddress ());
      in0 = client0.getInputStream ();
      out0 = client0.getOutputStream ();
      out0.write ("Welcome. Please wait.\r\n".getBytes ("latin1"));
      System.out.println ("Waiting..");
      Socket client1 = server.accept ();
      System.out.println ("Accepted from " + client1.getInetAddress ());
      in1 = client1.getInputStream ();
      out1 = client1.getOutputStream ();
      out1.write ("Welcome.\r\n".getBytes ("latin1"));
      out0.write ("Proceed.\r\n".getBytes ("latin1"));
    } finally {
      server.close ();
    }
  }

  static int readNB (InputStream in) throws IOException {
    if (in.available () > 0)
      return in.read ();
    else
      return -2;
  }
}