import java.awt.image.BufferedImage;

/**
 *
 */
public class SpaceInvaders extends JFrame implements Runnable {

    public static int WIDTH = 600;//The width of the frame
    public static int HEIGHT = 400;//The height of the frame

    private int gameSpeed = 100;//Try 500

    AlienArmy army = null;

    Ship ship = null;

    private boolean paused = false;

    private int score = 0;

    Graphics offscreen_high;
    BufferedImage offscreen;

    Image backGroundImage = null;
    Image alienImage = null;

    /**
     * This is called a constructor.
     */
    public SpaceInvaders(String frameTitle) {
        super(frameTitle);

        backGroundImage = new javax.swing.ImageIcon("back3.jpg").getImage();

        alienImage = new javax.swing.ImageIcon("alien.jpg").getImage();

        //Create the ship to fight off the invading army!
        ship = new Ship(this);

        //Create the alien army
        army = new AlienArmy(ship, this, alienImage);

        //The ship will be controlled by the mouse
        addMouseListener(ship);
        //We also want mouse movement not just mouse clicks
        addMouseMotionListener(ship);

        offscreen = new BufferedImage(WIDTH, HEIGHT,BufferedImage.TYPE_INT_RGB);
        offscreen_high = offscreen.createGraphics();

        setBackground(Color.black);
        setSize(WIDTH, HEIGHT);
        setVisible(true);
        startGame();
    }

    /**
     * As you move your mouse on and off the screen we want to pause
     * the game.
     */
    public void pauseGame(boolean state) {
        paused = state;
    }

    /**
     * Kill an alien and get 5 points!
     */
    public void hitAlienScore() {
        //Add 5 to the score
        score += 5;
        System.out.println("Current Score = "+score);
    }

    /**
     * Get shot and loose 20 points!
     */
    public void shotShip() {
        score -= 20;
        System.out.println("Current Score = "+score);
    }

    /**
     *
     */
    public void startGame() {
        //These two lines may look confusing but basically they start the
        //game process, i.e. update the display screen every 100ms.
        Thread thread = new Thread(this);
        thread.start();
    }

    /**
     *
     */
    public void paint(Graphics g) {
        offscreen_high.setColor(Color.black);
        offscreen_high.fillRect(0,0, WIDTH, HEIGHT);

        army.drawArmy(offscreen_high);

        ship.drawShip(offscreen_high);

        g.drawImage(offscreen,0,0,this);
    }

    public void update(Graphics g) {
        paint(g);
    }

    /**
     *
     */
    public void moveAliens() {
        army.moveArmy();
    }

    /**
     *
     */
    public void run() {
        int count = 0;
        while(true) {
            try {
                Thread.sleep(gameSpeed);
            } catch(InterruptedException ie) {
                //Ignore this exception
            }
            //If the game is currently running, move the aliens
            if (!paused) {
                if (count >= 5) {
                    moveAliens();
                    count = 0;
                }
            }
            repaint();//Update the screen
            count ++;

        }
    }

    /**
     * Get a reference to the alien army
     */
    public AlienArmy getAlienArmy() {
        return army;
    }

    /**
     * This is the program entry point
     */
    public static void main(String []args) {
        SpaceInvaders invaders = new SpaceInvaders("Space Invaders");
    }

}