import { ref, watch, onUnmounted } from 'vue'
import { getActivityContributionsLatestApi } from '@/utils/api.js'

/**
 * 贡献轮询逻辑 composable
 * @param {Ref<string>} activityId - 活动ID
 * @param {boolean} isPageActive - 页面是否可见
 * @returns {Object} records, visible, loading, error, start, stop, reset
 */
export function useContributionPolling(activityId, isPageActive) {
  const MAX_RECORDS = 5
  const POLL_INTERVAL = 1000 // 每秒拉取
  const RECORD_TTL = 5000 // 每条记录 5 秒后消失

  const records = ref([])
  const visible = ref(true)
  const loading = ref(false)
  const error = ref(null)

  let latestTimestamp = 0 // 当前列表中最新记录的时间戳
  let latestId = 0 // 当前列表中最新记录的 ID（同时间戳内二次筛选用）
  let pollingTimer = null
  let isPolling = false
  const recordTimers = new Map()

  // 重置记录计时器
  function resetRecordTimer(record) {
    // 清除已有定时器
    if (recordTimers.has(record.id)) {
      clearTimeout(recordTimers.get(record.id))
      recordTimers.delete(record.id)
    }
    // 清除淡出状态（新数据到来时重置）
    const target = records.value.find(r => r.id === record.id)
    if (target) {
      target.fading = false
    }
    // 设置新的消失定时器
    const timer = setTimeout(() => {
      // 标记为淡出状态
      const target = records.value.find(r => r.id === record.id)
      if (target) {
        target.fading = true
        // 等待动画完成后移除
        setTimeout(() => {
          records.value = records.value.filter(r => r.id !== record.id)
          recordTimers.delete(record.id)
        }, 500)
      } else {
        recordTimers.delete(record.id)
      }
    }, RECORD_TTL)
    recordTimers.set(record.id, timer)
  }

  // 获取最新贡献记录
  async function fetchLatest() {
    if (!activityId.value) return

    try {
      const res = await getActivityContributionsLatestApi(activityId.value, latestTimestamp, latestId, 1)

      // 处理 code 不为 200 的情况（静默忽略）
      if (res.code !== 200) return

      const newRecords = res.data?.records || []
      if (newRecords.length === 0) return

      const newRecord = newRecords[0]

      // 检测到新记录（时间戳更新，或时间戳相同但 ID 更新）
      const isNew = newRecord.created_at > latestTimestamp ||
        (newRecord.created_at === latestTimestamp && newRecord.id > latestId)

      if (isNew) {
        // 重置所有现有记录的计时器（新数据到来，刷新列表）
        records.value.forEach(resetRecordTimer)
        // 新记录插入到列表头部
        records.value = [newRecord, ...records.value].slice(0, MAX_RECORDS)
        // 为新记录启动消失计时器
        resetRecordTimer(newRecord)
        // 更新时间戳和 ID
        latestTimestamp = newRecord.created_at
        latestId = newRecord.id
      }
    } catch (e) {
      // 网络错误等，静默忽略，继续等待下一次轮询
      console.error('[useContributionPolling] fetchLatest error:', e)
    }
  }

  // 全量拉取（首次或重新开始）
  async function fetchAll() {
    if (!activityId.value) return

    loading.value = true
    error.value = null

    try {
      const res = await getActivityContributionsLatestApi(activityId.value, 0, 0, MAX_RECORDS)

      if (res.code !== 200) {
        throw new Error(res.message || '获取贡献记录失败')
      }

      const newRecords = res.data?.records || []

      // 清除所有计时器
      recordTimers.forEach(timer => clearTimeout(timer))
      recordTimers.clear()

      // 重置列表
      records.value = newRecords

      // 为每条记录启动计时器
      newRecords.forEach(record => resetRecordTimer(record))

      // 更新 latestTimestamp 和 latestId
      if (newRecords.length > 0) {
        latestTimestamp = newRecords[0].created_at
        latestId = newRecords[0].id
      }
    } catch (e) {
      error.value = e.message || '获取贡献记录失败'
      console.error('[useContributionPolling] fetchAll error:', e)
    } finally {
      loading.value = false
    }
  }

  // 开始轮询
  function start() {
    if (pollingTimer) return
    if (!activityId.value) return

    isPolling = true
    // 如果 latestTimestamp 为 0，说明是首次或切换活动，清空列表
    if (latestTimestamp === 0) {
      records.value = []
    }
    fetchLatest()
    pollingTimer = setInterval(fetchLatest, POLL_INTERVAL)
  }

  // 停止轮询（保留状态）
  function stop() {
    if (pollingTimer) {
      clearInterval(pollingTimer)
      pollingTimer = null
    }
    // 停止所有记录的计时器
    recordTimers.forEach(timer => clearTimeout(timer))
    recordTimers.clear()
    isPolling = false
    // 不清空 records、latestTimestamp、latestId，保留状态以便恢复
  }

  // 重置所有状态（切换活动时用）
  function reset() {
    stop()
    latestTimestamp = 0
    latestId = 0
    records.value = []
  }

  // 监听页面可见性
  watch(isPageActive, (active) => {
    if (active) {
      visible.value = true
      start()
    } else {
      visible.value = false
      stop()
    }
  }, { immediate: true })

  // 监听 activityId 变化
  watch(activityId, (newId, oldId) => {
    if (newId !== oldId) {
      reset()
      if (isPageActive.value && newId) {
        start()
      }
    }
  })

  // 组件卸载时清理
  onUnmounted(() => {
    reset()
  })

  return {
    records,
    visible,
    loading,
    error,
    start,
    stop,
    reset
  }
}