import { ref } from 'vue'

export function useDialogRotation() {
  let timer = null
  let screenWidth = 375
  let screenHeight = 812

  const initDialogRotation = ({ screenW, screenH }) => {
    screenWidth = screenW
    screenHeight = screenH
  }

  const isCabinInViewport = (cabin) => {
    return new Promise((resolve) => {
      const query = uni.createSelectorQuery()
      query.select(`#cabin-${cabin.key}`).boundingClientRect((rect) => {
        if (!rect) {
          resolve(false)
          return
        }
        
        const visibleTop = Math.max(0, rect.top)
        const visibleBottom = Math.min(screenHeight, rect.bottom)
        const visibleLeft = Math.max(0, rect.left)
        const visibleRight = Math.min(screenWidth, rect.right)
        const visibleWidth = Math.max(0, visibleRight - visibleLeft)
        const visibleHeight = Math.max(0, visibleBottom - visibleTop)
        const visibleArea = visibleWidth * visibleHeight
        const totalArea = rect.width * rect.height
        const visiblePercent = totalArea > 0 ? visibleArea / totalArea : 0
        
        resolve(visiblePercent > 0.7)
      }).exec()
    })
  }

  const rotateDialogVisibility = async (cabins) => {
    if (!cabins.length) return

    // 先全部重置为 false
    cabins.forEach(c => c.showDialog = false)

    // 筛选符合条件的 cabin：有昵称、有展位剩余
    const hasData = cabins.filter(c => c.nickname && c.sharedBoothSlotsRemaining !== null)

    // 批量检查所有 cabin 是否在可视区域内
    const viewportChecks = await Promise.all(hasData.map(c => isCabinInViewport(c)))
    const eligible = hasData.filter((c, i) => viewportChecks[i])

    if (eligible.length === 0) return

    // 随机选择 2-3 个
    const count = Math.min(Math.floor(Math.random() * 2) + 2, eligible.length, 3)
    const shuffled = eligible.sort(() => Math.random() - 0.5)
    for (let i = 0; i < count; i++) {
      shuffled[i].showDialog = true
    }
  }

  const startDialogRotation = (cabins) => {
    stopDialogRotation()
    
    const rotate = async () => {
      await rotateDialogVisibility(cabins)
      const interval = Math.floor(Math.random() * 1000) + 2000
      timer = setTimeout(rotate, interval)
    }
    
    rotate()
  }

  const stopDialogRotation = () => {
    if (timer) {
      clearTimeout(timer)
      timer = null
    }
  }

  return {
    initDialogRotation,
    startDialogRotation,
    stopDialogRotation,
  }
}