// Skeleton of a Java interactive program

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class Skeleton extends Applet {

    // Applet's global "state" of the interaction
    int lastX = 0;        // first click's x-y coordinates
    int lastY = 0;
    int clickNumber = 0;  // most recent click since last user choice.
    Choice choice;
    TextArea echoArea;  
    TextField typing;

    // Initializing the Frame
    public void init() {
        
        // Set the background color and listen for the mouse
        setBackground(Color.white);
        addMouseListener(new MouseHandler());
		
        // Create a button and add it to the Frame.
        Button clearButton = new Button("Clear");
        clearButton.setForeground(Color.black);
        clearButton.setBackground(Color.lightGray);
        add(clearButton);
        clearButton.addActionListener(new ClearButtonHandler());

        // Create a menu of user choices and add it to the Frame.
        choice = new Choice();
        choice.addItem("Nothing");
        choice.addItem("Rectangle");
        choice.addItem("Message");
        add(choice);
        choice.addItemListener(new ChoiceHandler());

        // Create a TextField and a TextArea and add them to
        // the Frame.
        typing = new TextField(40);
        add(typing);
        typing.addActionListener(new TextHandler());
        echoArea = new TextArea(2, 40);
        echoArea.setEditable(false);
        add(echoArea);
    }

    // Handling events that occur in the frame

    // Called when the user clicks the mouse button
    private class MouseHandler extends MouseAdapter {
	public void mouseClicked(MouseEvent e) { 
	    int x = e.getX();
	    int y = e.getY();
	    echoArea.setText("Mouse Clicked at " + 
			     e.getX() + ", " + e.getY() + "\n");
	    Graphics g = getGraphics();
	    if (choice.getSelectedItem().equals("Rectangle")) {
		clickNumber = clickNumber + 1;
		// is it the first click?
		if (clickNumber % 2 == 1) {  
		    echoArea.append("Click to set lower right corner of the rectangle");
		    lastX = x;
		    lastY = y;
		}
		// or the second?
		else g.drawRect(lastX, lastY, Math.abs(x-lastX), Math.abs(y-lastY));
	    }
	    else if (choice.getSelectedItem().equals("Message")) 
		// for a message, display it
		g.drawString(typing.getText(), x, y);          
	} // mouseClicked
    }

    // Called when the user selects clear Button
    private class ClearButtonHandler implements ActionListener {
	public void actionPerformed (ActionEvent e) {
            echoArea.setText("Clear button selected ");
            repaint();
        }
    }
    
    // Called when the user selects TextArea
    private class TextHandler implements ActionListener {
	public void actionPerformed (ActionEvent e) {
            echoArea.setText("Text entered: " + typing.getText());
            if (choice.getSelectedItem().equals("Message"))
               echoArea.append("\nNow click to place this message");
        }
    }
    
    // Called when the user selects a Choice
    private class ChoiceHandler implements ItemListener {
	public void itemStateChanged (ItemEvent e) {
	    String c =  (String) (e.getItem());
	    echoArea.setText("Choice selected: " + c);
	    // prepare to handle first mouse click for this choice
	    clickNumber = 0;
	    if (c.equals("Rectangle"))
		echoArea.append("\nClick to set upper left corner of the rectangle");                  
	    else if (c.equals("Message")) 
		echoArea.append("\nEnter a message in the text area");  
	}
    }    
}