public class MyWorld extends World
{
    private final int START = 0;
    private final int PLAYING1 = 1;
    private final int PLAYING2 = 2;
    private final int SUSPENDED = 3;
    private final int WIN = 4;
    private final int LOSE = 5;
    private int SPAWN_TIMER = 0;
    private int SPAWN_TIMER2 = 0;
    private int SPAWN_TIME_LIMIT = 65;
    private int SPAWN_TIME_LIMIT2 = 80;
    private int ENEMY_COUNTER = 0;
    private int ENEMY_COUNTER2 = 0;
    private int ENEMY_Y = 300;
    private Counter theCounter;
    private Counter theCounter2;
    
    private int curState;
    /**
     * Constructor for objects of class MyWorld.
     * 
     */
    public MyWorld()
    {    
        // Create a new world with 900x600 cells with a cell size of 1x1 pixels.
        super(900, 600, 1);
        theCounter = new Counter();
        curState = START;
        this.setBackground("start.jpg");
    }
    public void act() {
        
        // This starts the game whenever the player is ready
        if (curState == START && Greenfoot.isKeyDown("y") || Greenfoot.isKeyDown("Y"))
        {
            curState = PLAYING1;
            this.setBackground("PLAYING1.png");
            initializeLevel1();
        }
        
        // This spawns enemies at a certain rate
        if (curState == PLAYING1 && ENEMY_COUNTER < 15) {
            if (SPAWN_TIMER == SPAWN_TIME_LIMIT){
                spawnEnemy1();
                SPAWN_TIMER = 0;
                ENEMY_COUNTER ++;
            }
            else { 
                SPAWN_TIMER ++;
            }
        }
        
        // This sets the game to a suspended level when the player
        // finishes level 1
        
        if(curState == PLAYING1 && theCounter.getValue() == 15)
        {
            curState = SUSPENDED;
            removeLevel1Objs();
            this.setBackground("splash2.png");
        }
        
        if (curState == SUSPENDED && (Greenfoot.isKeyDown("y") || Greenfoot.isKeyDown("Y")))
        {
            initializeLevel2();
            this.setBackground("level2.png");
            curState = PLAYING2;
        }
        
        if (curState == PLAYING2 && ENEMY_COUNTER2 < 4) 
        {
            if (SPAWN_TIMER == SPAWN_TIME_LIMIT2){
                spawnEnemy2();
                SPAWN_TIMER = 0;
                ENEMY_COUNTER2 ++;
            }
            else { 
                SPAWN_TIMER ++;
            }
        }
        
        if(curState == PLAYING2 && theCounter.getValue() == 19)
        {
            curState = WIN;
            removeLevel2Objs();
            this.setBackground("win.png");
        }
        
    }
    // utility methods
    private void initializeLevel1() 
    {
        this.addObject(new Player(),100,300);
        this.addObject(new Computer(), 700,300);
    }
    
    private void initializeLevel2()
    {
       this.addObject(new Player(), 100, 300);
       this.addObject(new Rock(), 450, 100);
       this.addObject(new Rock(), 450, 500);
    }
    
    private void removeLevel1Objs()
    {
        List<Computer> myCList = this.getObjects(Computer.class);
        List<Player> myPList = this.getObjects(Player.class);
        for(Computer curComp : myCList) {
            this.removeObject(curComp);
            }
        for(Player curComp : myPList) {
            this.removeObject(curComp);
        }
        
    }
    
    private void removeLevel2Objs()
    {
        List<Computer2> myC2List = this.getObjects(Computer2.class);
        List<Player> myPList = this.getObjects(Player.class);
        List<Rock> myRList = this.getObjects(Rock.class);
        for(Computer2 curComp : myC2List) {
            this.removeObject(curComp);
            }
        for(Player curComp : myPList) {
            this.removeObject(curComp);
        }
        for(Rock curComp : myRList) {
            this.removeObject(curComp);
        }
        
    }
    
    // Method used to spawn enemies in the world
    private void spawnEnemy1() 
    {
        this.addObject(new Computer(),700,Greenfoot.getRandomNumber(ENEMY_Y));
    }
    
    public void spawnEnemy2()
    {
        this.addObject(new Computer2(), 700, Greenfoot.getRandomNumber(ENEMY_Y));
    }
    public Counter getCounter()
    {
        return theCounter;
    }
}