import {RESOLUTION} from '@/constants.js'
import {System} from '@/ecs/index.js';

export default class FollowCamera extends System {

  reindex(entities) {
    super.reindex(entities);
    for (const id of entities) {
      this.updateCamera(this.ecs.get(id));
    }
  }

  tick() {
    for (const entity of this.ecs.changed(['Position'])) {
      this.updateCamera(entity);
    }
  }

  updateCamera(entity) {
    const {Camera, Position} = entity;
    if (Camera && Position) {
      const {AreaSize: {x, y}} = this.ecs.get(1);
      const [hx, hy] = [RESOLUTION.x / 2, RESOLUTION.y / 2];
      Camera.x = Math.max(hx, Math.min(Position.x, x - hx));
      Camera.y = Math.max(hy, Math.min(Position.y, y - hy));
    }
  }

}