<template>
  <view class="u-wrap">
    <navbar></navbar>
    <view class="u-menu-wrap">
      <scroll-view scroll-y scroll-with-animation class="u-tab-view menu-scroll-view" :scroll-top="scrollTop"
                   :scroll-into-view="itemId">
        <view v-for="(item,index) in tabs" :key="item.id" class="u-tab-item" :class="[current == index ? 'u-tab-item-active' : '']"
              @tap.stop="swichMenu(index)">
          <text class="u-line-1">{{item.name}}</text>
        </view>
      </scroll-view>
      <scroll-view :scroll-top="scrollRightTop" scroll-y scroll-with-animation class="right-box">
        <view class="page-view">
          <view class="class-item"
                :id="'item' + key" v-for="(value , key) in products"
                :key="key">
            <view class="item-title">
              <text>{{key}}</text>
            </view>
            <view class="item-container">
              <view class="thumb-box"
                    v-for="(item1, index1) in value"
                    :key="item1.id"
                    @click="$u.throttle(() => {toDetail(item1)}, 500)">
                <image class="item-menu-image" :src="item1.image ? item1.image.url : vuex_default_icon" mode="aspectFill"></image>
                <view class="item-menu-name">{{item1.name}}</view>
              </view>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
    <tabbar></tabbar>
  </view>
</template>
<script>
import navbar from "@/package_sub/pages/Shop/Navbar.vue";
import tabbar from "@/package_sub/pages/Shop/Tabbar.vue";
export default {
  components: {
    tabbar,
    navbar
  },
  data() {
    return {
      scrollTop: 0, //tab标题的滚动条位置
      oldScrollTop: 0,
      current: 0, // 预设当前项的值
      menuHeight: 0, // 左边菜单的高度
      menuItemHeight: 0, // 左边菜单item的高度
      itemId: '', // 栏目右边scroll-view用于滚动的id
      tabs: [],
      products: {},
      menuItemPos: [],
      scrollRightTop: 0, // 右边栏目scroll-view的滚动条高度
      timer: null, // 定时器

    }
  },
  onLoad() {

  },
  onReady() {
  },
  created() {
    this.getTabs()
  },
  methods: {
    toDetail(item) {
      this.$u.route({
        url: '/package_sub/pages/Shop/ProductDetail',
        params: {
          id: item.id
        }
      })
    },
    async getTabs() {
      try {
        const res = await this.$u.api.productCategory({
          is_tree: 1
        })
        this.tabs = res.list
        this.getProducts()
      } catch(err) {
        console.error(err)
      }
    },
    async getProducts() {
      try {
        let temp = {}
        const response = await Promise.all(this.tabs[this.current]['children']?.map(tab => this.$u.api.productList({
          product_category_id: tab.id,
          page_size: 99
        })))
        response.forEach((res, index) => {
          Object.defineProperty(temp, this.tabs[this.current]['children'][index]['name'], {
            value: res.list.data,
            enumerable: true
          })
        })
        this.products = temp;
        console.log(temp)
      } catch (err) {

      }
    },
    // 点击左边的栏目切换
    async swichMenu(index) {
      if (index == this.current) return;
      this.scrollRightTop = 0;
      this.$nextTick(_ => {
        this.current = index;
        this.leftMenuStatus(index);
        this.getProducts();
      })
    },
    // 获取一个目标元素的高度
    getElRect(elClass, dataVal) {
      new Promise((resolve, reject) => {
        const query = uni.createSelectorQuery().in(this);
        query.select('.' + elClass).fields({
          size: true
        }, res => {
          // 如果节点尚未生成，res值为null，循环调用执行
          if (!res) {
            setTimeout(() => {
              this.getElRect(elClass);
            }, 10);
            return;
          }
          this[dataVal] = res.height;
          resolve();
        }).exec();
      })
    },

    // 设置左边菜单的滚动状态
    async leftMenuStatus(index) {
      this.current = index;
      // 如果为0，意味着尚未初始化
      if (this.menuHeight == 0 || this.menuItemHeight == 0) {
        await this.getElRect('menu-scroll-view', 'menuHeight');
        await this.getElRect('u-tab-item', 'menuItemHeight');
      }
      // 将菜单活动item垂直居中
      this.scrollTop = index * this.menuItemHeight + this.menuItemHeight / 2 - this.menuHeight / 2;
    },
  }
}
</script>

<style lang="scss" scoped>
.u-wrap {
  height: calc(100vh);
  /* #ifdef H5 */
  height: calc(100vh - var(--window-top));
  /* #endif */
  display: flex;
  flex-direction: column;
}

.u-search-box {
  padding: 18rpx 30rpx;
}

.u-menu-wrap {
  flex: 1;
  display: flex;
  overflow: hidden;
}

.u-search-inner {
  background-color: rgb(234, 234, 234);
  border-radius: 100rpx;
  display: flex;
  align-items: center;
  padding: 10rpx 16rpx;
}

.u-search-text {
  font-size: 26rpx;
  color: $u-tips-color;
  margin-left: 10rpx;
}

.u-tab-view {
  width: 200rpx;
  height: 100%;
}

.u-tab-item {
  height: 110rpx;
  background: #f6f6f6;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26rpx;
  color: #444;
  font-weight: 400;
  line-height: 1;
}

.u-tab-item-active {
  position: relative;
  color: #000;
  font-size: 30rpx;
  font-weight: 600;
  background: #fff;
}

.u-tab-item-active::before {
  content: "";
  position: absolute;
  border-left: 4px solid $u-type-primary;
  height: 32rpx;
  left: 0;
  top: 39rpx;
}

.u-tab-view {
  height: 100%;
}

.right-box {
  background-color: rgb(250, 250, 250);
}

.page-view {
  padding: 16rpx;
}

.class-item {
  margin-bottom: 30rpx;
  background-color: #fff;
  padding: 16rpx;
  border-radius: 8rpx;
}

.item-title {
  font-size: 26rpx;
  color: $u-main-color;
  font-weight: bold;
}

.item-menu-name {
  font-weight: normal;
  font-size: 24rpx;
  color: $u-main-color;
  white-space: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
  max-width: 180rpx;
}

.item-container {
  display: flex;
  flex-wrap: wrap;
}

.thumb-box {
  width: 33.333333%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  margin-top: 20rpx;
}

.item-menu-image {
  width: 120rpx;
  height: 120rpx;
}
</style>
