import { System } from '../core/System.ts';
import { SystemName, ComponentType } from '../core/Constants.ts';
import type { Entity } from '../core/Entity.ts';
import type { Health } from '../components/Health.ts';

/**
 * System responsible for managing health regeneration for entities over time.
 */
export class HealthRegenerationSystem extends System {
  constructor() {
    super(SystemName.HEALTH_REGEN);
    this.requiredComponents = [ComponentType.HEALTH];
    this.priority = 35;
  }

  /**
   * Process health regeneration for entities that haven't been damaged recently.
   * @param deltaTime - Time elapsed since last frame in seconds
   * @param entities - Entities matching system requirements
   */
  process(deltaTime: number, entities: Entity[]): void {
    entities.forEach((entity) => {
      const health = entity.getComponent<Health>(ComponentType.HEALTH);
      if (!health || health.regeneration <= 0) return;

      const timeSinceDamage = (Date.now() - health.lastDamageTime) / 1000;
      if (timeSinceDamage > 5) {
        health.heal(health.regeneration * deltaTime);
      }
    });
  }
}