<template>
  <ul v-if="items.length" class="sidebar-links">
    <li v-for="(item, i) in items" :key="i">
      <SidebarGroup
        v-if="item.type === 'group'"
        :item="item"
        :open="i === openGroupIndex"
        :collapsable="item.collapsable || item.collapsible"
        :depth="depth"
        :sidebar-depth="5"
        @toggle="toggleGroup(i)"
      />
      <SidebarLink v-else :sidebar-depth="5" :item="item" />
    </li>
  </ul>
</template>

<script>
import SidebarGroup from '@theme/components/SidebarGroup.vue'
import SidebarLink from '@theme/components/SidebarLink.vue'
import { isActive } from '../util'
// import {debounce} from 'lodash'

export default {
  name: 'SidebarLinks',
  components: { SidebarGroup, SidebarLink },
  props: [
    'items',
    'depth', // depth of current sidebar links
    'sidebarDepth' // depth of headers to be extracted
  ],
  data() {
    return {
      openGroupIndex: 0
    }
  },
  watch: {
    $route() {
      this.refreshIndex()
    }
  },
  created() {
    this.refreshIndex()
  },
  methods: {
    refreshIndex() {
      const index = resolveOpenGroupIndex(this.$route, this.items)
      if (index > -1) {
        this.openGroupIndex = index
      }
    },
    toggleGroup(index) {
      this.openGroupIndex = index === this.openGroupIndex ? -1 : index
    },
    isActive(page) {
      return isActive(this.$route, page.regularPath)
    }
  }
}
function resolveOpenGroupIndex(route, items) {
  for (let i = 0; i < items.length; i++) {
    const item = items[i]
    if (descendantIsActive(route, item)) {
      return i
    }
  }
  return -1
}
function descendantIsActive(route, item) {
  if (item.type === 'group') {
    return item.children.some(child => {
      if (child.type === 'group') {
        return descendantIsActive(route, child)
      } else {
        return child.type === 'page' && isActive(route, child.path)
      }
    })
  }
  return false
}
</script>
