import java.lang.System;
import java.net.Socket;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.io.*;

public class PortTalkApp {
  public static void main(String args[]){
    PortTalk portTalk = new PortTalk(args);
    portTalk.displayDestinationParameters();
    portTalk.displayLocalParameters();
    portTalk.chat();
    portTalk.shutdown();
  }
}

class PortTalk {
  Socket connection;
  DataOutputStream outStream;
  BufferedReader inStream;

  public PortTalk(String args[]){
    if(args.length!=2) error("Usage: java PortTalkApp host port");
    String destination = args[0];
    int port = 0;
    try {
      port = Integer.valueOf(args[1]).intValue();
    }catch (NumberFormatException ex){
      error("Invalid port number");
    }
    try{
      connection = new Socket(destination,port);
    }catch (UnknownHostException ex){
      error("Unknown host");
    }
    catch (IOException ex){
      error("IO error creating socket");
    }
    try{
      inStream = new BufferedReader(
      new InputStreamReader(connection.getInputStream()));
      outStream = new DataOutputStream(connection.getOutputStream());
    }catch (IOException ex){
      error("IO error getting streams");
    }
    System.out.println("Connected to "+destination+" at port "+port+".");
  }

  public void displayDestinationParameters(){
    InetAddress destAddress = connection.getInetAddress();
    String name = destAddress.getHostName();
    byte ipAddress[] = destAddress.getAddress();
    int port = connection.getPort();
    displayParameters("Destination ",name,ipAddress,port);
  }
  
  public void displayLocalParameters(){
    InetAddress localAddress = null;
    try{
      localAddress = InetAddress.getLocalHost();
    }catch (UnknownHostException ex){
      error("Error getting local host information");
    }
    String name = localAddress.getHostName();
    byte ipAddress[] = localAddress.getAddress();
    int port = connection.getLocalPort();
    displayParameters("Local ",name,ipAddress,port);
  }
  
  public void displayParameters(String s,String name,
    byte ipAddress[],int port){
    System.out.println(s+"host is "+name+".");
    System.out.print(s+"IP address is ");
    for(int i=0;i<ipAddress.length;++i)
    System.out.print((ipAddress[i]+256)%256+".");
    System.out.println();
    System.out.println(s+"port number is "+port+".");
  }
  
  public void chat(){
    BufferedReader keyboardInput = new BufferedReader(
    new InputStreamReader(System.in));
    boolean finished = false;
    do {
      try{
        System.out.print("Send, receive, or quit (S/R/Q): ");
        System.out.flush();
        String line = keyboardInput.readLine();
        if(line.length()>0){
          line=line.toUpperCase();
          switch (line.charAt(0)){
          case 'S':
            String sendLine = keyboardInput.readLine();
            outStream.writeBytes(sendLine);
            outStream.write(13);
            outStream.write(10);
            outStream.flush();
          break;
          case 'R':
            int inByte;
            System.out.print("***");
            while ((inByte = inStream.read()) != '\n')
            System.out.write(inByte);
            System.out.println();
          break;
          case 'Q':
            finished=true;
          break;
          default:
          break;
          }
        }
      }catch (IOException ex){
        error("Error reading from keyboard or socket");
      }
    } while(!finished);
  }
  
  public void shutdown(){
    try{
      connection.close();
    }catch (IOException ex){
      error("IO error closing socket");
    }
  }
  
  public void error(String s){
    System.out.println(s);
    System.exit(1);
  }
}