import { ref, watch, onUnmounted, type Ref } from 'vue'
import { getTaskStatus } from '../api/tasks'

export function useTaskPoller(taskIdRef: Ref<string | null>) {
  const status = ref<string>('')
  const isPolling = ref(false)
  const error = ref<string | null>(null)
  const result = ref<any>(null)
  let timer: any = null

  const start = () => {
    if (!taskIdRef.value) return
    isPolling.value = true
    error.value = null
    status.value = 'PENDING'

    timer = setInterval(async () => {
      try {
        const res = await getTaskStatus(taskIdRef.value!)
        status.value = res.status

        if (res.status === 'SUCCESS') {
          result.value = res
          stop()
        } else if (res.status === 'FAILED') {
          error.value = res.error || '任务执行失败'
          stop()
        }
      } catch (e: any) {
        error.value = '网络请求失败，请检查后端状态'
        stop()
      }
    }, 2000)
  }

  const stop = () => {
    isPolling.value = false
    if (timer) clearInterval(timer)
  }

  // 监听 Task ID 变化自动开启轮询
  watch(taskIdRef, (newVal) => {
    stop()
    if (newVal) start()
  })

  // 组件销毁时清理定时器
  onUnmounted(() => stop())

  return { status, isPolling, error, result, stop }
}