import { mapGetters } from 'vuex'

export default {
  /* 提供页面间存在数据传递需要的通用规范 */
  data() {
    return {
      prevData: {}
    }
  },
  computed: {
    ...mapGetters(['currentUser'])
  },
  created() {
    const cacheKey = this.$route.query.cacheKey || ''
    const data = cacheKey ? localStorage.getItem(cacheKey) : this.$route.query.data
    this.prevData = JSON.parse(decodeURIComponent(data || '{}'))
  },
  methods: {
    // transferUrl方法是给上一个页面用的
    // config是下一个页面需要的数据格式
    // extra是额外的参数提供源，可以是数组，如果当前页面存在prevData，方法会自动引入，不用2次传入
    transferData(config, extra) {
      if (!config) return {}
      let source = {
        ...this.prevData
      }
      if (extra) {
        if (Array.isArray(extra)) {
          // eslint-disable-next-line no-return-assign
          extra.forEach(single => source = {
            ...source,
            ...single
          })
        } else {
          source = {
            ...source,
            ...extra
          }
        }
      }
      // pick
      const nextData = {}
      const nextKeys = Array.isArray(config) ? config : Object.keys(config)
      // eslint-disable-next-line no-return-assign
      nextKeys.forEach(key => nextData[key] = source[key])
      return nextData
    },
    transferTo: function(path, config = null, extra = null, useReplace = false, cacheKey = '') {
      if (typeof config === 'boolean') useReplace = config
      if (typeof extra === 'boolean') useReplace = extra
      if (!extra && typeof config === 'object') extra = config
      const nextData = this.transferData(config, extra)
      console.log('transfer next data:', nextData)
      // 以此解决query会将所有参数转化为string的问题
      let query = this.isEmptyObject(nextData) ? null : { data: encodeURIComponent(JSON.stringify(nextData)) }
      if (cacheKey) {
        const safeKey = this.generateSafeKey(cacheKey)
        localStorage.setItem(safeKey, query.data)
        query = { cacheKey: safeKey, ts: new Date().getTime() }
      }
      const location = typeof path === 'string' ? {
        path: path,
        query: query
      } : query ? {
        ...path,
        query: query
      } : path
      console.log('transfer merged location:', location)
      if (useReplace !== '_blank') {
        return useReplace ? this.$router.replace(location) : this.$router.push(location)
      } else {
        window.open(this.$router.resolve(location).href, '_blank')
      }
    },
    generateSafeKey(key) {
      return `${key}_${this.currentUser.userName}`
    },
    isEmptyObject(obj) {
      if (!obj) return true
      return Object.keys(obj).length === 0
    }
  }
}