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

public class MissileLauncher
{  
   private static final int X_SIZE = 600, Y_SIZE = 800;  

   public static void main(String[ ] args)
   {
      JFrame frame = new JFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setSize(X_SIZE, Y_SIZE);
      GraphicsPanel panel = new GraphicsPanel();
      panel.setFocusable(true);
      frame.add(panel);
      frame.setVisible(true);
   }
   
   private static class GraphicsPanel extends JPanel implements KeyListener, ActionListener
   {
   		private int x,y;	// x, y coordinate of the launcher
   		private int dx;		// speed of the missile launcher moving horizontally
   		private int mx, my;  // x, y coordinate of the missile
   				// change mx, my into an array if desired, but add
   				// an int called numMissiles
   		private int score;
   		// add a spaceship to shoot at (ex, ey for its x,y, edx, edy for its motion)
		private Timer t;
		
		public GraphicsPanel()
		{
			x=X_SIZE/2-5;y=740;		// location of missile launcher
			dx=0;					// launcher not moving to start
			mx=-1;					// no missile currently in flight
			my=-1;					
			// randomly place the enemy spaceship and its motion
			score=0;
			addKeyListener(this);
			t=new Timer(10, this);
			t.start();
		}   		
			
		public void actionPerformed(ActionEvent e)
		{					
			// move the launcher
			x+=dx;
			if(x>X_SIZE-30)	dx=0;
			else if(x<30)	dx=0;
			
			// if the missile is launched, move it
			if(mx!=-1)
			{	
				my=my-4;
				if(my<10)
				{
					mx=-1;
					my=-1;
				}
				// once moved, check to make sure the missile
				// is still on the screen, if not reset mx and my to -1
				
				// also check to see if mx, my has touched the enemy ship
				// if so, add 1 to score and change the location of the ship
			}
			
			// move the enemy ship, randomly change its direction occasionally
			//		(see the Spaceship1.java program)
			repaint();
		}
		public void keyTyped(KeyEvent e) {}
		public void keyReleased(KeyEvent e) {} 
		public void keyPressed(KeyEvent e) 
		{
			// get the key entered and determine if
			// you should change dx (for instance, moving
			// left might do dx=dx-1; and moving right
			// might do dx=dx+1; but do not like dx
			// become < -3 or > +3 or it will move too fast
			// enter key will stop the launcher (dx=0)
			if(e.getKeyCode()==KeyEvent.VK_LEFT)
			{
				dx--;
				if(dx<-3) dx=-3;
			}
			if(e.getKeyCode()==KeyEvent.VK_RIGHT)
			{
				dx++;
				if(dx>3) dx=3;
			}
			if(e.getKeyCode()==KeyEvent.VK_DOWN)
			{
				dx=0;
			}	
			if(e.getKeyCode()==KeyEvent.VK_SPACE&&mx==-1)
			{ 
				mx=x;
				my=y;
			}					
		}
		
		public void paintComponent(Graphics g)
		{
			super.paintComponent(g);
			g.setColor(Color.black);
			g.fillRect(0,0,X_SIZE,Y_SIZE);
			g.setColor(Color.red);
			g.drawLine(x,y,x+5,y+5);
			g.drawLine(x,y,x-5,y+5);
			g.drawLine(x+5,y+5,x-5,y+5);
			g.setColor(Color.white);
			g.drawLine(mx,my,mx,my-2);
			// draw the missile launcher
			// draw the missile(s) (if any)
			// draw the enemy ship
			// output the score
		}
   }
}