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

public class TimerExample extends JApplet implements KeyListener
{
	private Timer timer1;			// propels top player horizontally across screen
	private Timer timer2;			// propels bottom player horizontally across screen
	private Timer timerBullet2;		// propels bottom player's bullet vertically up the screen
	private int x1;					// the x location of top player
	private int x2;					// the x location of bottom player
	private int bullet2Y;			// the y location of bottom player's bullet
	private int bullet2X;			// the x location of bottom player's bullet
	private int moveAmount1;		// the top player's horizontal move amount in each timer step
	private int moveAmount2;		// the bottom player's horizontal move amount in each timer step
	private int player2Score;
		
	public void init() 
	{
		x1 = 0;						
		x2 = 500;
		bullet2X = -10;
		bullet2Y = 180;
		addKeyListener(this);
		
		 //instantiate each timer and give each its own "inner class" ActionListener
	    timer1 = new Timer(200, new ActionListener() 
	    {
	        public void actionPerformed(ActionEvent evt) 
	        {
	           if (x1 <= 0)			// right and left boundary collision detection
	           {
	           		moveAmount1 = 10;
	           }
	           else if (x1 >= 500)
	           {
	           		moveAmount1 = -10;
	           }
	           
	           x1 += moveAmount1;	// moving top player horizontally across screen
	           repaint();
	        }
	    });	
	    
	    timer2 = new Timer(200, new ActionListener() 
	    {
	        public void actionPerformed(ActionEvent evt) 
	        {

	           if (x2 <= 0)			// right and left boundary collision detection
	           {
	           		moveAmount2 = 10;
	           }
	           else if (x2 >= 500)
	           {
	           		moveAmount2 = -10;
	           }
	           
	           x2 += moveAmount2;	// moving bottom player horizontally across screen
	           repaint();
	        }
	    });	
	     
	    timerBullet2 = new Timer(100, new ActionListener() 
	    {
	        public void actionPerformed(ActionEvent evt) 
	        {	           
	           if (bullet2X >= x1 && bullet2X <= x1 + 10 && bullet2Y <= 10 && bullet2Y >= 0)
	           {
	           		player2Score++;      			           
	           }
	           
	           if (bullet2Y <= 10)	// bullet boundary collision detection
	           {
	           		timerBullet2.stop();
	           }
	           
	           bullet2Y -= 10;		// moving bullet vertically up the screen
	           repaint();
	        }
	    });	
	}
	
	public void start()
	{
		timer1.start();
		timer2.start();
	}

	public void paint(Graphics g)
	{
		requestFocus();
		g.setColor(Color.white);					// covering over last player and bullet graphics
		g.drawRect(x1 - moveAmount1, 10, 20, 20);
		g.drawRect(x2 - moveAmount2, 200, 20, 20);
		g.drawLine(bullet2X, -20, bullet2X, 310);
		g.fillRect(20, 220, 60, 190);
		
		g.setColor(Color.black);					// moving player and bullet graphics
		g.drawRect(x1, 10, 20, 20);
		g.drawRect(x2, 200, 20, 20);
		g.drawLine(bullet2X, bullet2Y, bullet2X, bullet2Y - 10);
		g.drawString("score: " + new Integer(player2Score).toString(), 30, 250);
		g.drawString("press spacebar to fire missile", 10, 280);
	}
   
  	public void keyTyped(KeyEvent key)
	{

   		if (key.getKeyChar() == ' ' && !timerBullet2.isRunning())		// space bar shoots missile
   		{
   			bullet2X = x2;
   			bullet2Y = 180;
       		timerBullet2.start();
   		}
	} 
	
	public void keyPressed(KeyEvent e) { }
    public void keyReleased(KeyEvent e) { }
}