/** @param difficulty Which difficulty level the game model should be on. */
public GameModel(Difficulty difficulty) {
bulletManager = new BulletManager();
enemyManager = new EnemyManager();
pickupManager = new PickupManager();
WeaponFactory.initialize(bulletManager);
enemySpawner = new EnemySpawner(new RandomWaveList(difficulty));
enemySpawner.addPropertyChangeListener(enemyManager);
player = new Player(PlayerID.PLAYER1, bulletManager);
pcs = new PropertyChangeSupport(this);
// Player listens when enemies are killed
enemyManager.addPropertyChangeListener(player);
}
