// Skeleton of an interactive program for Lab 9

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

public class Skeleton extends Applet implements MouseListener, ActionListener,
                                                ItemListener {

// Variables used by the Applet -- this is the global "state" of the interaction
     int last_x = 0;        // first click's x-y coordinates
     int last_y = 0;
     int click_number = 0;  // most recent click since last user choice.
     String currentChoice = "";  // most recent user choice
     String currentMessage = ""; // most recent user typing
     Button clear_button;
     Choice user_choices;
     TextArea echo_area;  
     TextField user_typing;

// Initializing the Frame -- this establishes the objects and their listeners
    public void init() {
        
        // Set the background color and listen for the mouse
        setBackground(Color.white);
        addMouseListener(this);
		
        // Create a button and add it to the Frame.
        clear_button = new Button("Clear");
        clear_button.setForeground(Color.black);
        clear_button.setBackground(Color.lightGray);
        add(clear_button);
        clear_button.addActionListener(this);

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

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

// Hendling events that occur in the frame -- these methods change the
// state and the appearance of the frame    

    // Called when the user clicks the mouse button
    public void mouseClicked(MouseEvent e) { 
       int x = e.getX();
       int y = e.getY();
       echo_area.setText("Mouse Clicked at " + 
                         e.getX() + ", " + e.getY() + "\n");
       Graphics g = this.getGraphics();
       // was it the first mouse click since the last choice was made?
       if (click_number==0) {
           click_number = 1;
           if (currentChoice.equals("Message")) 
              g.drawString(currentMessage, x, y); 
           // for a rectangle, save it and prepare for the second mouse click
           else if (currentChoice.equals("Rectangle")) {
               echo_area.setText("Click on lower right corner of the rectangle");
               last_x = x;
               last_y = y;
           }
       }
       // or the second?
       else {
           click_number = 0;
           if (currentChoice.equals("Rectangle"))  
              g.drawRect(last_x, last_y, Math.abs(x-last_x), Math.abs(y-last_y));
       }
    } 
    public void mouseExited(MouseEvent e) { } 
    public void mouseEntered(MouseEvent e) { } 
    public void mousePressed (MouseEvent e) { }    
    public void mouseReleased (MouseEvent e) { }  

    // Called when the user selects a Button or TextArea
    public void actionPerformed (ActionEvent e) {
        Graphics g = this.getGraphics();

        // If the Clear button was clicked, handle it; clear the frame.
        if (e.getSource() == clear_button) {
            echo_area.setText("Clear button selected ");
            Rectangle r = this.bounds();
            g.setColor(this.getBackground());
            g.fillRect(r.x, r.y, r.width, r.height);
        }
        // Otherwise if some text was typed, handle that; save the text
        else if (e.getSource() == user_typing) {
            currentMessage = user_typing.getText();
            echo_area.setText("Text entered: " + currentMessage);
            if (currentChoice.equals("Message"))
               echo_area.setText(echo_area.getText() + 
                                 "\nNow click to place this message");
        }
    }
    
    // Called when the user makes a Choice selection
    public void itemStateChanged (ItemEvent e) {
        currentChoice =  (String) (e.getItem());
        echo_area.setText("Choice selected: " + currentChoice);
        click_number = 0; // prepare to handle first mouse click for this choice
        if (currentChoice.equals("Rectangle"))
           echo_area.setText(echo_area.getText() + "\nClick on upper left corner of the rectangle");                  
        if (currentChoice.equals("Message")) 
           echo_area.setText(echo_area.getText() + "\nEnter a message in the text area");  
    }    
}