// 简单 sleep 工具，供重试间隔等待使用。
export function sleep(ms) {
  return new Promise((resolve) => {
    setTimeout(resolve, ms)
  })
}

/**
 * 通用重试执行器。
 * @param {(retryIndex:number)=>Promise<any>} fn 被执行函数
 * @param {object} options
 * @param {number} options.retries 失败后最大重试次数
 * @param {number} options.delay 每次重试前等待毫秒
 * @param {(error:any,retryIndex:number)=>boolean} options.shouldRetry 是否重试
 */
export async function runWithRetry(fn, options = {}) {
  const {
    retries = 2,
    delay = 500,
    shouldRetry = () => true
  } = options

  let lastError = null

  for (let index = 0; index <= retries; index += 1) {
    try {
      return await fn(index)
    } catch (error) {
      lastError = error

      if (index >= retries || !shouldRetry(error, index)) {
        throw error
      }

      await sleep(delay)
    }
  }

  throw lastError
}