export interface QueueObject {
  animate: (...args: any[]) => Promise<any>;
  context: any;
  args?: any[];
  onError?: (error: any) => void;
}

export class AnimationQueue {
  private __running = false;
  private __queueObjects: QueueObject[] = [];

  push(o: QueueObject): void {
    if (this.__running) {
      this.__queueObjects.push(o);
    } else {
      this.__running = true;
      this.__animate(o);
    }
  }

  clear(): void {
    this.__queueObjects = [];
  }

  private __animate(o: QueueObject): void {
    const __this = this;
    try {
      if (!o.animate) {
        return;
      }

      o.animate
        .apply(o.context, !!o.args ? o.args : [])
        .then(() => {
          if (0 < __this.__queueObjects.length) {
            const __o = __this.__queueObjects.shift();
            if (!!__o) {
              __this.__animate.call(__this, __o);
            } else {
              __this.__running = false;
            }
          }
        })
        .catch(reason => {
          if (!!o.onError) {
            o.onError.apply(o.context, [reason]);
          }
        });
    } catch (e) {
      if (!!o.onError) {
        o.onError.apply(o.context, [e]);
      }
    }
  }
}