export interface GenerationPollingProcessor {
  processNext(): Promise<unknown>;
}

export class GenerationPollingLoop {
  private closed = false;
  private inFlight = false;
  private readonly timer: ReturnType<typeof setInterval>;

  constructor(
    private readonly processor: GenerationPollingProcessor,
    intervalMilliseconds = 250,
  ) {
    if (!Number.isSafeInteger(intervalMilliseconds) || intervalMilliseconds <= 0) {
      throw new Error("generation_polling_interval_invalid");
    }
    this.timer = setInterval(() => this.run(), intervalMilliseconds);
  }

  close() {
    if (this.closed) return;
    this.closed = true;
    clearInterval(this.timer);
  }

  private run() {
    if (this.closed || this.inFlight) return;
    this.inFlight = true;
    void this.processor.processNext()
      .catch(() => undefined)
      .finally(() => {
        this.inFlight = false;
      });
  }
}