<!--

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.

-->
<template>
  <div v-if="!item.hidden&&item.children" class="menu-wrapper">

    <template v-if="hasOneShowingChild(item.children,item) && (!onlyOneChild.children||onlyOneChild.noShowingChildren)&&!item.alwaysShow">
      <app-link :to="resolvePath(onlyOneChild.path)">
        <el-menu-item :index="resolvePath(onlyOneChild.path)" :class="{'submenu-title-noDropdown':!isNest}">
          <item v-if="onlyOneChild.meta" :icon="onlyOneChild.meta.icon||item.meta.icon" :title="generateTitle(onlyOneChild.meta.title)" />
        </el-menu-item>
      </app-link>
    </template>

    <el-submenu v-else ref="submenu" :index="resolvePath(item.path)">
      <template slot="title">
        <item v-if="item.meta" :icon="item.meta.icon" :title="generateTitle(item.meta.title)" />
      </template>

      <template v-for="child in item.children" v-if="!child.hidden">
        <sidebar-item
          v-if="child.children&&child.children.length>0"
          :is-nest="true"
          :item="child"
          :key="child.path"
          :base-path="resolvePath(child.path)"
          class="nest-menu" />

        <app-link v-else :to="resolvePath(child.path)" :key="child.name">
          <el-menu-item :index="resolvePath(child.path)">
            <item v-if="child.meta" :icon="child.meta.icon" :title="generateTitle(child.meta.title)" />
          </el-menu-item>
        </app-link>
      </template>
    </el-submenu>

  </div>
</template>

<script>
import path from 'path'
import { generateTitle } from '@/utils/i18n'
import { isExternal } from '@/utils'
import Item from './Item'
import AppLink from './Link'
import FixiOSBug from './FixiOSBug'

export default {
  name: 'SidebarItem',
  components: { Item, AppLink },
  mixins: [FixiOSBug],
  props: {
    // route object
    item: {
      type: Object,
      required: true
    },
    isNest: {
      type: Boolean,
      default: false
    },
    basePath: {
      type: String,
      default: ''
    }
  },
  data() {
    return {
      onlyOneChild: null
    }
  },
  methods: {
    hasOneShowingChild(children, parent) {
      const showingChildren = children.filter(item => {
        if (item.hidden) {
          return false
        } else {
          // Temp set(will be used if only has one showing child)
          this.onlyOneChild = item
          return true
        }
      })

      // When there is only one child router, the child router is displayed by default
      if (showingChildren.length === 1) {
        return true
      }

      // Show parent if there are no child router to display
      if (showingChildren.length === 0) {
        this.onlyOneChild = { ... parent, path: '', noShowingChildren: true }
        return true
      }

      return false
    },
    resolvePath(routePath) {
      if (this.isExternalLink(routePath)) {
        return routePath
      }
      return path.resolve(this.basePath, routePath)
    },
    isExternalLink(routePath) {
      return isExternal(routePath)
    },
    generateTitle
  }
}
</script>