// SwingDemo.java
// A very brief demo of creating a Swing-based application and/or applet
// Code written quickly in class on 1-May-08 (and so may not have ideal style, etc...)

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.io.*;

public class SwingDemo extends JApplet {

  private boolean isApplet = false;
  
  // This is ONLY CALLED IF WE ARE AN APPLICATION AND NOT AN APPLET
  public static void main(String[] args) {
    new SwingDemo().launchApp();
  }
  
  // This is ONLY CALLED IF WE ARE AN APPLET AND NOT AN APPLICATION
  public void start() {
    this.isApplet = true;
    start(this.getContentPane());
  }
  
  public void saveToFile(String filename, String text) {
    try {
      PrintStream out = new PrintStream(new File(filename));    
      out.print(text);    
    }
    catch (Exception e) {
      String s = "Could not save to file: " + filename;
      if (this.isApplet) s += " (as expected for an applet)";
      JOptionPane.showMessageDialog(null, s, "error", JOptionPane.ERROR_MESSAGE);
    }
  }
  
  public String getTextFromFile(String filename) {
    try {
      Scanner scanner = new Scanner(new File(filename));
      StringBuffer sb = new StringBuffer();
      while (scanner.hasNext()) {
        sb.append(scanner.nextLine());
        sb.append("\n");
      }
      fileTextField.setText(filename);
      return sb.toString();
    }
    catch (Exception e) {
      String s = "Could not open file: " + filename;
      if (this.isApplet) s += " (as expected for an applet)";
      return s;
    }
  }

  private JTextPane textPane = new JTextPane();
  private JTextField fileTextField = new JTextField("a.txt", 20);
  
  public void doSaveAction() {
    saveToFile(fileTextField.getText(),textPane.getText());
  }

  public void doLoadAction() {
    textPane.setText(getTextFromFile(fileTextField.getText()));
  }

  
  public void launchApp() {
    JFrame frame = makeFrame("SwingDemo");
    Container cp = frame.getContentPane();
    start(cp);
    frame.pack();
    frame.setVisible(true);
  }
  
  // shared by both the applet and the application code
  private void start(Container cp) {
    JPanel northBar = new JPanel();
    northBar.setLayout(new FlowLayout());    
    northBar.add(new JLabel("file:"));
    northBar.add(fileTextField);
    
    ActionListener listener = new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        String action = e.getActionCommand();
        if (action.equals("save"))
          doSaveAction();
        else if (action.equals("load"))
          doLoadAction();
        else
          Toolkit.getDefaultToolkit().beep();
      }
    };

    JButton saveButton = new JButton("save");
    saveButton.setMnemonic(KeyEvent.VK_S);
    saveButton.setToolTipText("Save the current contents to the given file");
    saveButton.setActionCommand("save");
    saveButton.addActionListener(listener);
    
    JButton loadButton = new JButton("load");
    loadButton.setActionCommand("load");
    loadButton.addActionListener(listener);

    northBar.add(saveButton);
    northBar.add(loadButton);
    
    // textPane.setBackground(new Color(220,220,255));
    textPane.setBackground(Color.blue);
    textPane.setForeground(Color.white);
    textPane.setFont(new Font("courier",Font.BOLD,24));
    textPane.setText(getCeleryText());
    
    JScrollPane sp = new JScrollPane(textPane);

    cp.setLayout(new BorderLayout());
    cp.add(northBar,BorderLayout.NORTH);
    cp.add(sp,BorderLayout.CENTER);
  }
  
  public static JFrame makeFrame(String title) {
    JFrame frame = new JFrame(title);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    return frame;
  }
  
  public static String getCeleryText() {
    return "Celery\n" +
           "By Ogden Nash\n" +
           "\n" +
           "Celery, raw\n" +
           "Develops the jaw,\n" +
           "But celery, stewed,\n" +
           "Is more quietly chewed.\n";
  }
}