/**
 * 数据加载监听
 */
module.exports = Behavior({
  data: {
    cPage: 1,
    tPage: 1,
    totalCount: 0,
    loading: false,
    needLoadMore: false
  },
  observers: {
    'loading': function (loading) {
      if (loading) {
        this._loadStart()
        this._loading()
      } else {
        this._loadComplete()
      }
    },
    'cPage, tPage': function (cPage, tPage) {
      this.setData({
        needLoadMore: cPage < tPage
      })
    },
    'reachBottom': function(reachBottom) {
      if (reachBottom) {
        this._onReachBottom()
      }
    },
  },
  methods: {
    _onReachBottom() {
      console.log('_onReachBottom');
      let {cPage, tPage, loading} = this.data
      if (!loading && cPage < tPage) {
        if (typeof this.loadmore === 'function') {
          this.loadmore(cPage)          
        }
      }
    },
    // 加载开始通知
    _loadStart() {
      this.triggerEvent('loadStart')
      if (typeof this.loadStart === 'function') {
        this.loadStart()
      }
    },
    // 加载中通知
    _loading() {
      this.triggerEvent('loading')
      if (typeof this.loading === 'function') {
        this.loading()
      }
    },
    // 加载完成通知
    _loadComplete() {
      this.triggerEvent('loadComplete')
      if (typeof this.loadComplete === 'function') {
        this.loadComplete()
      }
    }
  }
})