export class Progress {
  private _startTime: number | null = null;
  private _elapsedTime: number = 0;
  private _remainingTime: number = 0;

  get value(): number {
    return this._remainingTime;
  }

  next(progress: number): void {
    if (progress > 0 && this._startTime === null) {
      this._startTime = Date.now();
    }

    if (progress > 0 && this._startTime !== null) {
      this._elapsedTime = (Date.now() - this._startTime) / 1000; // in seconds
      if (progress > 0) {
        const speed = this._elapsedTime / progress;
        this._remainingTime = speed * (1 - progress);
      }
    }
  }
}