import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.util.*;


public class Explosion extends Actor
{
    /**
     * Act - do whatever the Explosion wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    public void act() 
    {
        // Add your action code here.
    }    
}

/**
 * An explosion. It starts by expanding and then collapsing. 
 * The explosion will explode other obejcts that the explosion intersects.
 */
public class Explosion extends Actor{;
    /** How many images should be used in the animation of the explostion */
    private final static int IMAGE_COUNT= 1;
}
    /** 
     * The images in the explosion. This is static so the images are not
     * recreated for every object (improves performance significantly).
     */
    private static GreenfootImage[] images;
    
    /** Current size of the explosion */
    private int imageNo = 0;
    
    /** How much do we increment the index in the explosion animation. */
    private int increment=1;    
    
    public Explosion() {
        initialiseImages();
        setImage(images[0]);        
        Greenfoot.playSound("Explosion.wav");
    }    
    
    /** 
     * Create the images for explosion.
     */
    public synchronized static void initialiseImages() {
        if(images == null) {
            GreenfootImage baseImage = new GreenfootImage("explosion.png");
            int maxSize = baseImage.getWidth()/2;
            int delta = maxSize / (IMAGE_COUNT+1);
            int size = 0;
            images = new GreenfootImage[IMAGE_COUNT];
            for(int i=0; i < IMAGE_COUNT; i++) {
                size = size + delta;
                images[i] = new GreenfootImage(baseImage);
                images[i].scale(size, size);
            }
        }
    }
    
    /**
     * EXPLODE!
     */
    public void act()
    { 
        if(imageNo > 0) {
            setImage(images[imageNo]);
        }

        imageNo += increment;
        if(imageNo >= IMAGE_COUNT) {
            increment = -increment;
            imageNo += increment;
        }
        
        if(imageNo <= 0) {
            setImage(new GreenfootImage(1,1));
        }
        if(imageNo <= -30) {
            ((Space) getWorld()).gameOver();
        }
    }
}