<template>
  <div>
    <div class="goods">
      <div class="menu-wrapper" ref="menuWrapper">
        <ul>
          <li v-for="(item,index) in goods" class="menu-item" :class="{'current':currentIndex===index}"
              @click="selectMenu(index,$event)" ref="menuList">
          <span class="text border-1px">
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>{{item.name}}
          </span>
          </li>
        </ul>
      </div>
      <div class="foods-wrapper" ref="foodsWrapper">
        <ul>
          <li v-for="item in goods" class="food-list" ref="foodList">
            <h1 class="title">{{item.name}}</h1>
            <ul>
              <li @click="selectFood(food,$event)" v-for="food in item.foods" class="food-item border-1px">
                <div class="icon">
                  <img width="57" height="57" :src="food.icon">
                </div>
                <div class="content">
                  <h2 class="name">{{food.name}}</h2>
                  <p class="desc">{{food.description}}</p>
                  <div class="extra">
                    <span class="count">月售{{food.sellCount}}份</span><span>好评率{{food.rating}}%</span>
                  </div>
                  <div class="price">
                    <span class="now">￥{{food.price}}</span><span class="old"
                                                                  v-show="food.oldPrice">￥{{food.oldPrice}}</span>
                  </div>
                  <div class="cartcontrol-wrapper">
                    <cartcontrol @add="addFood" :food="food"></cartcontrol>
                  </div>
                </div>
              </li>
            </ul>
          </li>
        </ul>
      </div>
      <shopcart ref="shopcart" :selectFoods="selectFoods" :deliveryPrice="seller.deliveryPrice"
                :minPrice="seller.minPrice"></shopcart>
    </div>
    <food @add="addFood" :food="selectedFood" ref="food"></food>
  </div>
</template>

<script type="text/ecmascript-6">
import BScroll from 'better-scroll'
import shopcart from '../shopcart/shopcart'
import cartcontrol from '../cartcontrol/cartcontrol'
import food from '../food/food'

const ERR_OK = 0
const debug = process.env.NODE_ENV !== 'production'
const goods = require('../../../mock/data.json')

export default {
  props: {
    seller: {
      type: Object
    }
  },
  data () {
    return {
      goods: [],
      listHeight: [],
      scrollY: 0,
      selectedFood: {}
    }
  },
  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)) {
          this._followScroll(i)
          return i
        }
      }
      return 0
    },
    selectFoods () {
      let foods = []
      this.goods.forEach((good) => {
        good.foods.forEach((food) => {
          if (food.count) {
            foods.push(food)
          }
        })
      })
      return foods
    }
  },
  created () {
    this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee']

    const url = 'http://ustbhuangyi.com/sell/api/goods'
    this.$http.get(url).then((response) => {
      response = response.body
      if (response.errno === ERR_OK) {
        this.goods = response.data
        this.$nextTick(() => {
          this._initScroll()
          this._calculateHeight()
        })
      }
    })
  },
  methods: {
    selectMenu (index, event) {
      if (!event._constructed) {
        return
      }
      let foodList = this.$refs.foodList
      let el = foodList[index]
      this.foodsScroll.scrollToElement(el, 300)
    },
    selectFood (food, event) {
      if (!event._constructed) {
        return
      }
      this.selectedFood = food
      this.$refs.food.show()
    },
    addFood (target) {
      this._drop(target)
    },
    _drop (target) {
      // 体验优化,异步执行下落动画
      this.$nextTick(() => {
        this.$refs.shopcart.drop(target)
      })
    },
    _initScroll () {
      this.meunScroll = new BScroll(this.$refs.menuWrapper, {
        click: true
      })

      this.foodsScroll = new BScroll(this.$refs.foodsWrapper, {
        click: true,
        probeType: 3
      })

      this.foodsScroll.on('scroll', (pos) => {
        // 判断滑动方向，避免下拉时分类高亮错误（如第一分类商品数量为1时，下拉使得第二分类高亮）
        if (pos.y <= 0) {
          this.scrollY = Math.abs(Math.round(pos.y))
        }
      })
    },
    _calculateHeight () {
      let foodList = this.$refs.foodList
      let height = 0
      this.listHeight.push(height)
      for (let i = 0; i < foodList.length; i++) {
        let item = foodList[i]
        height += item.clientHeight
        this.listHeight.push(height)
      }
    },
    _followScroll (index) {
      let menuList = this.$refs.menuList
      let el = menuList[index]
      this.meunScroll.scrollToElement(el, 300, 0, -100)
    }
  },
  components: {
    shopcart,
    cartcontrol,
    food
  }
}
</script>

<style lang="scss" scoped></style>
