import { ref, onUnmounted } from 'vue'

/**
 * 自适应间隔轮询：tick 返回后按 getInterval() 调度下一次
 * @param {() => Promise<void>|void} tickFn
 * @param {() => number} getIntervalMs
 */
export function useLivePoll(tickFn, getIntervalMs = () => 1000) {
  const lastTickAt = ref(null)
  const ticking = ref(false)
  let timer = null
  let inFlight = false
  let running = false

  async function runTick() {
    if (inFlight) return
    inFlight = true
    ticking.value = true
    try {
      await tickFn()
      lastTickAt.value = Date.now()
    } catch (e) {
      console.error('[livePoll]', e)
    } finally {
      inFlight = false
      ticking.value = false
    }
  }

  function scheduleNext() {
    if (!running) return
    clearTimeout(timer)
    const ms = Math.max(500, getIntervalMs())
    timer = setTimeout(async () => {
      await runTick()
      scheduleNext()
    }, ms)
  }

  function start() {
    if (running) return
    running = true
    runTick().then(scheduleNext)
  }

  function stop() {
    running = false
    clearTimeout(timer)
    timer = null
  }

  function restart() {
    stop()
    start()
  }

  onUnmounted(stop)

  return { start, stop, restart, runTick, lastTickAt, ticking }
}