<script type="text/ecmascript-6">
import BScroll from 'better-scroll';
const ERR_OK = 0;
export default {
 props: {
  sell: {
   type: Object
  }
 },
 data() {
  return {
   goods: [],
   listHeight: [],
   scrollY: 0
  };
 },
 computed: {
  currentIndex() {
   for (let i = 0; i < this.listHeight.length; i++) {
    let height1 = this.listHeight[i];
    let height2 = this.listHeight[i + 1];
    if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
     return i;
    };
   }
   return 0;
  }
 },
 created() {
  this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee'];
  this.$http.get('/api/goods').then((response) => {
   response = response.body;
   if (response.errno === ERR_OK) {
    this.goods = response.data;
    this.$nextTick(() => {
     this._initScroll();
     this._calculateHeight();
    });
   }
  });
 },
 methods: {
  _initScroll() {
   this.menuScroll = new BScroll(this.$refs.menuwrapper, {
    click: true
   });
   this.foodScroll = new BScroll(this.$refs.foodswrapper, {
    probeType: 3
   });
   this.foodScroll.on('scroll', (pos) => {
    this.scrollY = Math.abs(Math.round(pos.y));
   });
  },
  _calculateHeight() {
   let foodList = this.$refs.foodswrapper.getElementsByClassName('food-list-hook');
   let height = 0;
   this.listHeight.push(height);
   for (let i = 0; i < foodList.length; i++) {
    let item = foodList[i];
    height += item.clientHeight;
    this.listHeight.push(height);
   }
  },
  selectMenu(index, event) {
   if (!event._constructed) {
    return;
   };
   console.log(index);
   let foodList = this.$refs.foodswrapper.getElementsByClassName('food-list-hook');
   let el = foodList[index];
   this.foodScroll.scrollToElement(el, 300);
  }
 }
};
</script>