import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class TCPEchoClientGUI extends JFrame {

  public static void main(String[] args) {
    if ((args.length < 1) || (args.length > 2)) {
      throw new IllegalArgumentException("Parameter(s): <Server> [<Port>]");
    }

    String server = args[0]; // Server name or IP address
    int servPort = (args.length == 2) ? Integer.parseInt(args[1]) : 7;

    JFrame frame = new TCPEchoClientGUI(server, servPort);
    frame.setVisible(true);
  }

  public TCPEchoClientGUI(String server, int servPort) {
    super("TCP Echo Client"); // Set the window title
    setSize(300, 300); // Set the window size
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    // Set echo send text field
    final JTextField echoSend = new JTextField();
    getContentPane().add(echoSend, "South");

    // Set echo replay text area
    final JTextArea echoReply = new JTextArea(8, 20);
    echoReply.setEditable(false);
    JScrollPane scrollPane = new JScrollPane(echoReply);
    getContentPane().add(scrollPane, "Center");

    final Socket socket; // Client socket
    final DataInputStream in; // Socket input stream
    final OutputStream out; // Socket output stream
    try {
      // Create socket and fetch I/O streams
      socket = new Socket(server, servPort);

      in = new DataInputStream(socket.getInputStream());
      out = socket.getOutputStream();
      echoSend.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent event) {
          if (event.getSource() == echoSend) {
            byte[] byteBuffer = echoSend.getText().getBytes();
            try {
              out.write(byteBuffer);
              in.readFully(byteBuffer);
              echoReply.append(new String(byteBuffer) + "\n");
              echoSend.setText("");
            } catch (IOException e) {
              echoReply.append("ERROR\n");
            }
          }
        }
      });

      addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          try {
            socket.close();
          } catch (Exception exception) {
          }
          System.exit(0);
        }
      });
    } catch (IOException exception) {
      echoReply.append(exception.toString() + "\n");
    }
  }
}