/**
 * Base System class for ECS architecture
 * Systems contain logic that operates on entities with specific components
 */
export class System {
  constructor(name) {
    this.name = name;
    this.requiredComponents = [];
    this.priority = 0; // Lower priority runs first
  }

  /**
     * Check if an entity matches this system's requirements
     */
  matches(entity) {
    if (!entity.active) return false;
    return this.requiredComponents.every(componentType =>
      entity.hasComponent(componentType)
    );
  }

  /**
     * Update method - override in subclasses
     */
  update(deltaTime, entities) {
    // Filter entities that match this system's requirements
    const matchingEntities = entities.filter(entity => this.matches(entity));
    this.process(deltaTime, matchingEntities);
  }

  /**
     * Process matching entities - override in subclasses
     */
  process(_deltaTime, _entities) {
    // Override in subclasses
  }

  /**
     * Called when system is added to engine
     */
  init(engine) {
    this.engine = engine;
  }
}