import objectdraw.*;
import java.util.Random;

// Animated ball for the breakout game
public class BreakoutBall extends ActiveObject {

    // Ball's initial speed
    private final static double INIT_Y = 100;
    private static final double XSPEED_SCALER = 3;

    // Size of ball
    private static final double BALLSIZE = 10;

    // delay between moves
    private static final double DELAY = 30;

    // the ball itself
    private FilledOval theBall;

    // the bricks ball might bounce off
    private BreakoutBricks bricks;

    // the boundary within which the ball should stay
    private DrawingCanvas canvas;

    // the paddle trying to hit the ball
    private FilledRect paddle;

    // current ball speed
    private double xSpeed;
    private double ySpeed = -INIT_Y;

    // create a new ball.  remember all the things it might hit 
    public BreakoutBall(BreakoutBricks theBricks, FilledRect thePaddle, DrawingCanvas theCanvas) {

        // set a random X speed (positive or negative)
        Random rand = new Random();
        xSpeed = (rand.nextDouble() - 0.5) * XSPEED_SCALER * INIT_Y;

        // draw the ball
        theBall = new FilledOval(thePaddle.getX() + thePaddle.getWidth()/2,
            thePaddle.getY() - 2 * BALLSIZE, BALLSIZE, BALLSIZE, theCanvas);

        // remember the obstacles
        bricks = theBricks;
        paddle = thePaddle;
        canvas = theCanvas;
        start();
    }

    // bounce the ball around the playing area
    public void run() {

        double lastTime = System.currentTimeMillis();

        while (theBall.getY() < canvas.getHeight()) {

            pause(DELAY);

            double elapsedTime = System.currentTimeMillis() - lastTime;
            lastTime = lastTime + elapsedTime;

            theBall.move(elapsedTime * xSpeed / 1000, elapsedTime * ySpeed / 1000);

            // see if you need to bounce off one of the boundary's sides
            if (theBall.getX() < 0) {
                // bounce off left side
                xSpeed = -xSpeed;
            } else if (theBall.getX() + BALLSIZE > canvas.getWidth()) {
                // bounce off right side
                xSpeed = -xSpeed;
            }

            // see if you hit the top of the boundary
            if (theBall.getY() < 0) {
                ySpeed = -ySpeed;
            }

            // see if you hit a brick
            FilledRect hitBrick = bricks.getIntersectedBrick(theBall);
            if (hitBrick != null) {
                bounceOffRect(hitBrick);
            }

            // check the paddle
            if (theBall.overlaps(paddle)) {
                bounceOffRect(paddle);
            }
        }

    }

    // A crude approximation of the phsyical process
    // of a ball bouncing off a brick (or the paddle).
    private void bounceOffRect(FilledRect box) {
        double centerX = theBall.getX() + BALLSIZE/2;

        if (centerX > box.getX() && centerX < box.getX() + box.getWidth()) {
            // hit the top of the rectangle
            ySpeed = -ySpeed;
        } else {
            // hit the side of the rectangle
            xSpeed = -xSpeed;
        }
    }
    
}