pager.html

{{ $curr := . }}
{{ $next := "" }}
{{ $prev := "" }}

{{/* 1. Calculate PREVIOUS */}}
{{ if .Parent }}
  {{ $siblings := .Parent.Pages.ByWeight }}
  {{ $currIndex := -1 }}

  {{ range $index, $page := $siblings }}
    {{ if eq $page.RelPermalink $curr.RelPermalink }}
      {{ $currIndex = $index }}
    {{ end }}
  {{ end }}

  {{ if gt $currIndex 0 }}
    {{/* Preceding sibling (if it's a folder, this naturally points to its _index.md!) */}}
    {{ $prev = index $siblings (sub $currIndex 1) }}
  {{ else }}
    {{/* First child, so Previous points up to the Parent folder */}}
    {{ if ne .Parent.Type "home" }}
      {{ $prev = .Parent }}
    {{ end }}
  {{ end }}
{{ end }}


{{/* 2. Calculate NEXT */}}
{{ if and .IsNode (gt (len .Pages) 0) }}
  {{/* If it's a folder with children, Next dives into the first child */}}
  {{ $next = index .Pages.ByWeight 0 }}
{{ else }}
  {{/* Leaf page, or empty folder */}}
  {{ if .Parent }}
    {{ $siblings := .Parent.Pages.ByWeight }}
    {{ $currIndex := -1 }}

    {{ range $index, $page := $siblings }}
      {{ if eq $page.RelPermalink $curr.RelPermalink }}
        {{ $currIndex = $index }}
      {{ end }}
    {{ end }}

    {{ if lt $currIndex (sub (len $siblings) 1) }}
      {{/* Next sibling in the same folder */}}
      {{ $next = index $siblings (add $currIndex 1) }}
    {{ else }}
      {{/* Last item in folder, step out and find the Parent's next sibling */}}
      {{ $p := .Parent }}
      {{ $foundNext := false }}

      {{/* Check up to 3 directory levels up to find the next section */}}
      {{ range seq 3 }}
        {{ if and (not $foundNext) $p }}
          {{ if $p.Parent }}
            {{ $pSiblings := $p.Parent.Pages.ByWeight }}
            {{ $pIndex := -1 }}
            {{ range $index, $page := $pSiblings }}
              {{ if eq $page.RelPermalink $p.RelPermalink }}
                {{ $pIndex = $index }}
              {{ end }}
            {{ end }}

            {{ if and (ge $pIndex 0) (lt $pIndex (sub (len $pSiblings) 1)) }}
              {{ $next = index $pSiblings (add $pIndex 1) }}
              {{ $foundNext = true }}
            {{ else }}
              {{ $p = $p.Parent }}
            {{ end }}
          {{ else }}
            {{ $p = false }}
          {{ end }}
        {{ end }}
      {{ end }}

    {{ end }}
  {{ end }}
{{ end }}

<!-- 3. Render the Buttons -->
{{ if or $prev $next }}
<nav class="mt-5 pt-4 border-top d-flex justify-content-between" aria-label="Page navigation">

  <div>
    {{ with $prev }}
    <a href="{{ .RelPermalink }}" class="text-decoration-none">
      <small class="text-muted d-block mb-1">&laquo; Previous</small>
      <span class="text-body">{{ .Title }}</span>
    </a>
    {{ end }}
  </div>

  <div class="text-end">
    {{ with $next }}
    <a href="{{ .RelPermalink }}" class="text-decoration-none">
      <small class="text-muted d-block mb-1">Next &raquo;</small>
      <span class="text-body">{{ .Title }}</span>
    </a>
    {{ end }}
  </div>

</nav>
{{ end }}