/**
 * Small shared helpers for @pixu1980/pi-web.
 */

export function generateId(): string {
  return Date.now().toString(36) + Math.random().toString(36).slice(2, 8);
}

/**
 * Minimal promise-based semaphore that caps concurrent URL fetches.
 */
export class Semaphore {
  private active = 0;
  private readonly queue: Array<() => void> = [];

  constructor(private readonly max: number) {}

  async acquire(): Promise<void> {
    if (this.active < this.max) {
      this.active++;

      return;
    }

    await new Promise<void>((resolve) => {
      this.queue.push(resolve);
    });
    this.active++;
  }

  release(): void {
    this.active--;
    const next = this.queue.shift();

    if (next) {
      next();
    }
  }

  async run<T>(fn: () => Promise<T>): Promise<T> {
    await this.acquire();

    try {
      return await fn();
    } finally {
      this.release();
    }
  }
}