{{- $current := . -}}
{{- $area := partial "docs/nav-area" . -}}
{{- $home := .Site.Home -}}
{{- $homeTitle := i18n "docsOverview" -}}
{{- $groups := slice -}}
{{- $pages := slice -}}

{{- if eq $area "example" -}}
  {{- with .Site.GetPage "/docs/examples" -}}
    {{- $home = . -}}
    {{- $homeTitle = i18n "docsExampleOverview" -}}
    {{/* Each subsection, such as Quick Start or Advanced Usage, is one sidebar group. */}}
    {{- range .Sections.ByWeight -}}
      {{- $children := where .RegularPages.ByWeight "Params.bookHidden" "ne" true -}}
      {{- $groups = $groups | append (dict "Title" .Title "Page" . "Linked" false "Children" $children) -}}
    {{- end -}}
  {{- end -}}
{{- else if eq $area "research" -}}
  {{- with .Site.GetPage "/docs/research" -}}
    {{- $home = . -}}
    {{- $homeTitle = i18n "docsResearchOverview" -}}
    {{- $children := where .RegularPages.ByWeight "Params.bookHidden" "ne" true -}}
    {{- if $children -}}
      {{- $groups = $groups | append (dict "Title" (i18n "docsPapers") "Page" . "Linked" false "Children" $children) -}}
    {{- end -}}
  {{- end -}}
{{- else -}}
  {{- range slice "/docs/user-guide" "/docs/marl" "/docs/env" "/docs/dev" -}}
    {{- with $current.Site.GetPage . -}}
      {{- $children := where .RegularPages.ByWeight "Params.bookHidden" "ne" true -}}
      {{/* Environments keeps its linked overview page and curated group title. */}}
      {{- $env := eq .Path "/docs/env" -}}
      {{- $groups = $groups | append (dict "Title" (cond $env (i18n "docsEnvironments") .Title) "Page" . "Linked" $env "Children" $children) -}}
    {{- end -}}
  {{- end -}}
{{- end -}}

{{/* Sidebar and page-to-page links share one ordered list within each area. */}}
{{- $pages = $pages | append $home -}}
{{- range $groups -}}
  {{- if .Linked -}}
    {{- $pages = $pages | append .Page -}}
  {{- end -}}
  {{- range .Children -}}
    {{- if not .Params.BookHref -}}
      {{- $pages = $pages | append . -}}
    {{- end -}}
  {{- end -}}
{{- end -}}
{{- return (dict "Area" $area "Home" $home "HomeTitle" $homeTitle "Groups" $groups "Pages" $pages) -}}