Gamelib/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/EntityManager.java

package uulm.teamname.marvelous.gamelibrary.gamelogic;

import uulm.teamname.marvelous.gamelibrary.IntVector2;
import uulm.teamname.marvelous.gamelibrary.entities.Entity;
import uulm.teamname.marvelous.gamelibrary.entities.EntityID;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Iterator;

/** Represents a managed list of {@link Entity}s. */
public class EntityManager {
    /** The internal collection of {@link Entity}s */
    private final HashSet<Entity> entities = new HashSet<>();

    /**
     * Takes over all the entities from a different {@link EntityManager}.
     * @param other The entity list to take the data from
     */
    public void cloneFrom(EntityManager other) {
        entities.clear();
        for(Entity entity: other.entities) {
            entities.add(entity.clone());
        }
    }

    /**
     * Clears the list of entities.
     */
    public void clear() {
        entities.clear();
    }

    /**
     * Adds an entity to the list.
     * @param entity The {@link Entity} to add
     */
    public void addEntity(Entity entity) {
        entities.add(entity);
    }

    /**
     * Adds multiple entities to the list.
     * @param entities The entities to add
     */
    public void addEntities(Entity... entities) {
        this.entities.addAll(Arrays.asList(entities));
    }

    /**
     * Removes an entity from the list.
     * @param entity The {@link Entity} to remove
     */
    public boolean removeEntity(Entity entity) {
        return entities.remove(entity);
    }

    /**
     * Finds an entity with an {@link EntityID}.
     * @param id The id to search for
     * @return The found {@link Entity} or null if none found
     */
    public Entity findEntity(EntityID id) {
        for(Entity entity: entities) {
            if(entity.id == id) {
                return entity;
            }
        }
        return null;
    }

    /**
     * Finds all entities with a position.
     * @param pos The position to check on
     * @return The found {@link Entity}s matching the position
     */
    public ArrayList<Entity> findByPosition(IntVector2 pos) {
        ArrayList<Entity> found = new ArrayList<>();
        for(Entity entity: entities) {
            if(entity.getPosition() == pos) {
                found.add(entity);
            }
        }
        return found;
    }

    /**
     * Iterates over all entities inside the list.
     * @return An iterator over every {@link Entity}
     */
    public Iterator<Entity> getEntities() {
        return entities.iterator();
    }
}