import { ElMessage } from 'element-plus'

const DEFAULT_REQUEST_GUARD_TIMEOUT = 8e3
const DEFAULT_REQUEST_TIMEOUT_MESSAGE = '请求超时，已停止等待'

function withRequestGuard(task, fallbackValue, options = {}) {
  const { timeoutMs = DEFAULT_REQUEST_GUARD_TIMEOUT, onFallback } = options

  return new Promise((resolve) => {
    let settled = false

    const finish = (value, reason, error) => {
      if (settled) return
      settled = true
      clearTimeout(timer)
      if (typeof onFallback === 'function' && reason) {
        onFallback(reason, error)
      }
      resolve(value)
    }

    const timer = setTimeout(() => finish(fallbackValue, 'timeout'), timeoutMs)

    Promise.resolve(task).then(
      (value) => finish(value),
      (error) => finish(fallbackValue, 'error', error)
    )
  })
}

function guardRequestWithMessage(task, fallbackValue, options = {}) {
  const {
    timeoutMs = DEFAULT_REQUEST_GUARD_TIMEOUT,
    timeoutMessage = DEFAULT_REQUEST_TIMEOUT_MESSAGE,
    errorMessage,
    resolveErrorMessage
  } = options

  return withRequestGuard(task, fallbackValue, {
    timeoutMs,
    onFallback: (reason, error) => {
      if (reason === 'timeout') {
        if (timeoutMessage) {
          ElMessage.warning(timeoutMessage)
        }
        return
      }

      const resolvedMessage =
        typeof resolveErrorMessage === 'function'
          ? resolveErrorMessage(error)
          : errorMessage || error?.message

      if (resolvedMessage) {
        ElMessage.error(resolvedMessage)
      }
    }
  })
}

export {
  DEFAULT_REQUEST_GUARD_TIMEOUT,
  DEFAULT_REQUEST_TIMEOUT_MESSAGE,
  guardRequestWithMessage,
  withRequestGuard
}