// components/TopTabbar/index.js
Component({

  /**
   * 组件的属性列表
   */
  properties: {
    tabList: {
      type: Array,
      value: []
    },
    border: {
      type: Boolean,
      value: true
    },
    tabIndex: {
      type: Number,
      value: 0
    },
  },
  observers: {
    tabIndex: function (n) {
      this.click(n);
    },

  },
  /**
   * 组件的初始数据
   */
  data: {
    tabDataIndex: 0,
    scroll_width: 0,
    scroll_left: 0
  },
  lifetimes: {
    attached: function () {},
    detached: function () {},
  },
  pageLifetimes: {
    // 组件所在页面的生命周期函数
    show: function () {
      this.onLoad();
    },
    hide: function () {},
    resize: function () {},
  },
  /**
   * 组件的方法列表
   */
  methods: {
    onLoad() {
      var that = this;
      that.createSelectorQuery().select('#topTabbar-item').boundingClientRect(function (res) {
        try {
          that.setData({
            scroll_width: res.width
          })
        } catch (e) {}
      }).exec();
    },
    changeType(e) {
      var that = this;
      if (this.data.tabDataIndex == e.currentTarget.dataset.index) return;
      let index = e.currentTarget.dataset.index;
      let item = e.currentTarget.dataset.item;
      let offsetLeft = e.currentTarget.offsetLeft;
      let scroll_left = this.data.scroll_left;
      that.createSelectorQuery().select('#topTabbar_select_' + index).boundingClientRect(function (res) {
        // //console.log(res)
        scroll_left = offsetLeft - that.data.scroll_width / 2 + (res.width / 2);
        that.setData({
          tabDataIndex: index,
          scroll_left: scroll_left
        });
        that.triggerEvent('change', {
          index,
          item
        })
      }).exec();
    },
    click(eindex) {
      var that = this;
      if (this.data.tabDataIndex == eindex) return;
      let index = eindex;
      let item = this.data.tabList[eindex];
      let scroll_left = this.data.scroll_left;
      that.createSelectorQuery().select('#topTabbar_select_' + index).boundingClientRect(function (res) {
        scroll_left = res.left - that.data.scroll_width / 2 + (res.width / 2);
        that.setData({
          tabDataIndex: index,
          scroll_left: scroll_left
        });
        that.triggerEvent('change', {
          index,
          item
        })
      }).exec();
    }
  }
})