import java.util.ArrayList;
import java.util.List;

/**
 * Hitable interface.<br>
 * Classes implementing this interface can be hit.
 */
interface Hitable {
    void hit();
}

/**
 * Asteroid, destroyed when hit (invisible).
 */
class Asteroid implements Hitable {
    boolean isVisible = true;

    @Override
    public void hit() {
        isVisible = false;
    }

}

/**
 * When hit, the health is reduced by 1.
 */
class SpaceShip implements Hitable {
    int health = 100;

    @Override
    public void hit() {
        health--;
    }
}

/**
 * GameManager holds a list of all Entities in game.
 */
class GameMamanger {
    List<Hitable> hitableEntities = new ArrayList<>();

    void addEntity(Hitable entity) {
        hitableEntities.add(entity);
    }

    // iterate over all known hitable entities and check for hits
    void checkForHits() {
        for (Hitable entity : hitableEntities) {

            // TODO Game Logic, check for hits between Asteroids and Spaceship
            if (true) {
                // an entity is hit (Asteroid or Spaceship)
                entity.hit();
            }
        }
    }

}

public class SimpleTest1 {

    public static void main(String[] args) {
        // create asteroid
        Asteroid a1 = new Asteroid();
        Asteroid a2 = new Asteroid();

        // create player
        SpaceShip player = new SpaceShip();

        // create gamemanager and add all entities
        GameMamanger manager = new GameMamanger();
        manager.addEntity(a1);
        manager.addEntity(a2);
        manager.addEntity(player);

        // TODO game logic
        // Game Manager checks if hitable entities have been hit
        manager.checkForHits();

    }
}