export async function mapWithConcurrency<T, R>(
  items: readonly T[],
  concurrency: number,
  run: (item: T, index: number) => Promise<R>,
): Promise<R[]> {
  if (items.length === 0) return [];

  const workerCount = Math.max(1, Math.min(items.length, Math.trunc(concurrency)));
  const results = new Array<R>(items.length);
  let nextIndex = 0;

  async function worker(): Promise<void> {
    while (true) {
      const currentIndex = nextIndex;
      if (currentIndex >= items.length) return;
      nextIndex += 1;
      results[currentIndex] = await run(items[currentIndex], currentIndex);
    }
  }

  await Promise.all(Array.from({ length: workerCount }, () => worker()));
  return results;
}