<template>
  <el-breadcrumb class="app-breadcrumb" separator="/">
    <transition-group name="breadcrumb">
      <el-breadcrumb-item v-for="(item, index) in levelList" :key="item.path">
        <span v-if="item.redirect === 'noRedirect' || index == levelList.length - 1" class="no-redirect">{{ item.meta.title }}</span>
        <span v-else @click.prevent="handleLink(item)" style="cursor: pointer">
          {{ item.meta.title }}
        </span>
      </el-breadcrumb-item>
    </transition-group>
  </el-breadcrumb>
</template>

<script setup>
const route = useRoute()
const router = useRouter()
const levelList = ref([])

function getBreadcrumb() {
  // only show routes with meta.title
  let matched = route.matched.filter((item) => item.meta && item.meta.title)
  const first = matched[0]
  // 判断是否为首页
  if (!isDashboard(first)) {
    matched = [{ path: '/index', meta: { title: '首页' } }].concat(matched)
  }

  levelList.value = matched.filter((item) => item.meta && item.meta.title && item.meta.breadcrumb !== false)
}

function isDashboard(route) {
  const name = route && route.name
  if (!name) {
    return false
  }
  return name.trim() === 'Index'
}
function handleLink(item) {
  const { redirect, path } = item
  if (redirect) {
    router.push(redirect)
    return
  }
  router.push(path)
}

watchEffect(() => {
  // if you go to the redirect page, do not update the breadcrumbs
  if (route.path.startsWith('/redirect/')) {
    return
  }
  getBreadcrumb()
})
getBreadcrumb()
</script>

<style lang="scss" scoped>
.app-breadcrumb.el-breadcrumb {
  display: inline-block;
  font-size: 14px;
  line-height: 50px;
  margin-left: 8px;

  .no-redirect {
    color: #97a8be;
    cursor: text;
  }
}
.mobile .app-breadcrumb.el-breadcrumb {
  display: none;
}

.breadcrumb-move, /* 对移动中的元素应用的过渡 */
.breadcrumb-enter-active,
.breadcrumb-leave-active {
  transition: all 0.5s ease;
}
.breadcrumb-enter-from,
.breadcrumb-leave-to {
  opacity: 0;
  transform: translateX(30px);
}

/* 确保将离开的元素从布局流中删除
  以便能够正确地计算移动的动画。 */
.breadcrumb-leave-active {
  position: absolute;
}
</style>
