// Bugs.java
// Solution to CS 5 Lab Assignment #2 by THC.
// This applet puts up a window with a pink background.
// Wherever you double-click, a bug appears and moves toward the top
// of the applet window.
// If you single-click over any part of a bug, it disappears.
// If the location of a single-click is over more than one bug, then
// all the bugs at the click location disappear.
// The action stops when the mouse leaves the applet window, and it
// resumes when the mouse enters the applet window.

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import javax.swing.Timer;

public class Bugs extends Applet implements ActionListener, MouseListener {
  private final int APPLET_WIDTH = 500, APPLET_HEIGHT = 500;
  private final int MAXBUGS = 500;  // max number of Bugs we can have at once
  
  private Timer timer;        // a Timer for when the Bugs move up
  private Swarm infestation;  // maintains information about all existing Bugs
  
  // Initialize the applet.
  public void init() {
    final int DELAY = 100;      // how long between Timer events
    setSize(APPLET_WIDTH, APPLET_HEIGHT); // set the window size
    setBackground(Color.pink);  // use a pink background
    
    // Because we draw every Bug the same, it's most efficient to
    // tell the Bug class what image to draw and what applet will
    // be displaying the image.
    Bug.init(getImage(getCodeBase(), "bug0.gif"), this);
    
    // Create a Swarm object, initially with no Bugs.
    infestation = new Swarm(MAXBUGS);
    
    // Create the Timer and make this applet listen for Timer and mouse events.
    timer = new Timer(DELAY, this);
    timer.start();
    addMouseListener(this);
    
    // Display an empty window.
    repaint();
  }
  
  // To draw the applet window, draw all the existing Bugs and a string saying
  // how many Bugs there are right now.
  public void paint(Graphics page) {
    infestation.draw(page);
    
    page.setColor(Color.black);
    page.drawString("Bugs: " + infestation.getBugCount(), 10, APPLET_HEIGHT-10);
  }
  
  // When the Timer rings, move all the Bugs and redisplay the window.
  public void actionPerformed(ActionEvent event) {
    infestation.move();
    repaint();
  }
  
  // Handle a mouse click event.
  // If a single-click, hit all Bugs at the location of the click, terminating them.
  // If a double-click, add a new Bug at the location of the click.
  public void mouseClicked(MouseEvent event) {
    int clicks = event.getClickCount();   // how many clicks?
    Point where = event.getPoint();       // where is the mouse?
    
    if (clicks == 1)
      infestation.hitBugs(where);         // single-click: hit Bugs
    else if (clicks == 2)
      infestation.add(where);             // double-click: add a new Bug
  }
  
  // Start the Timer when the mouse enters the window.
  public void mouseEntered(MouseEvent event) {
    timer.start();
  }
  
  // Stop the Timer when the mouse exits the window.
  public void mouseExited(MouseEvent event) {
    timer.stop();
  }
  
  // Empty defintions for unused mouse events.
  public void mousePressed(MouseEvent event) {}
  public void mouseReleased(MouseEvent event) {}
}