import { System } from '../core/System.js';

export class ProjectileSystem extends System {
  constructor() {
    super('ProjectileSystem');
    this.requiredComponents = ['Position', 'Velocity'];
    this.priority = 18;
  }

  process(deltaTime, entities) {
    const playerController = this.engine.systems.find(s => s.name === 'PlayerControllerSystem');
    const _player = playerController ? playerController.getPlayerEntity() : null;

    entities.forEach(entity => {
      const health = entity.getComponent('Health');
      if (!health || !health.isProjectile) return;

      const position = entity.getComponent('Position');
      if (!position) return;

      // Check range - remove if traveled beyond max range
      if (entity.startX !== undefined && entity.startY !== undefined && entity.maxRange !== undefined) {
        const dx = position.x - entity.startX;
        const dy = position.y - entity.startY;
        const distanceTraveled = Math.sqrt(dx * dx + dy * dy);

        if (distanceTraveled >= entity.maxRange) {
          this.engine.removeEntity(entity);
          return;
        }
      }

      // Check lifetime as backup
      if (entity.lifetime !== undefined) {
        entity.lifetime -= deltaTime;
        if (entity.lifetime <= 0) {
          this.engine.removeEntity(entity);
          return;
        }
      }

      // Check collisions with enemies
      const allEntities = this.engine.getEntities();
      allEntities.forEach(target => {
        if (target.id === entity.owner) return;
        if (target.id === entity.id) return;
        if (!target.hasComponent('Health')) return;
        if (target.getComponent('Health').isProjectile) return;

        const targetPos = target.getComponent('Position');
        if (!targetPos) return;

        const dx = targetPos.x - position.x;
        const dy = targetPos.y - position.y;
        const distance = Math.sqrt(dx * dx + dy * dy);

        if (distance < 20) {
          // Hit!
          const targetHealth = target.getComponent('Health');
          const damage = entity.damage || 10;
          targetHealth.takeDamage(damage);

          // If target is dead, mark it for immediate removal
          if (targetHealth.isDead()) {
            target.active = false;
            // DeathSystem will handle removal
          }

          // Remove projectile
          this.engine.removeEntity(entity);
        }
      });

      // Boundary check
      const canvas = this.engine.canvas;
      if (position.x < 0 || position.x > canvas.width ||
                position.y < 0 || position.y > canvas.height) {
        this.engine.removeEntity(entity);
      }
    });
  }
}