export const withConcurrency = <TParams extends unknown[], TReturn>(
  fn: (...args: TParams) => Promise<TReturn>,
  limit: number
): {
    readonly activeCount: number;
    readonly pendingCount: number;
    queue: (...args: TParams) => void;
    run: () => Promise<TReturn[]>;
  } => {
  const queue: TParams[] = []
  const results: TReturn[] = []
  let activeCount = 0
  let pendingCount = 0
  let index = 0
  const worker = async () => {
    while (index < queue.length) {
      const currentIndex = index++
      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
      const args = queue[currentIndex]!
      activeCount++
      pendingCount--
      const result = await fn(...args)
      results[currentIndex] = result
    }
  }
  return {
    get activeCount () {
      return activeCount
    },
    get pendingCount () {
      return pendingCount
    },
    queue: (...args: TParams) => {
      queue.push(args)
      pendingCount++
    },
    run: async () => {
      const workerCount = Math.min(limit, queue.length)
      await Promise.all(Array.from({ length: workerCount }, worker))
      return results
    }
  }
}