{{ $this := . }}

<!-- Used to combine current file's headers with embed headers since .TableOfContents doesn't include embed headers -->
{{ $showEmbedHeaders := .Params.tocEmbedHeaders }}
{{ $headerRange := .Params.headerRange | default "[1-3]" }}
<!-- Ignore empty links with + -->
{{ $headers := findRE ( print "<h" $headerRange ".*?>(.|\n)+?</h" $headerRange ">") .Content }}
<!-- Must have at least one header to link to -->
{{ $has_headers := ge (len $headers) 1 }}

{{ with .TableOfContents }}
  <section class="hidden xl:block w-60 h-full shrink-0">
    <div class="w-60 z-40 overflow-auto fixed top-28 h-full max-h-[calc(100vh-15rem)] text-sm">
      {{ partial "meta-links.html" $this }}
      <!-- Combines current file's headers with embed headers since .TableOfContents doesn't include embed headers. Front matter must include "tocEmbedHeaders: true". -->
      {{ if and $showEmbedHeaders $has_headers }}
        <h2 class="font-medium my-3">On this page</h2>
        <nav class="text-slate-700">
          <nav id="TableOfContents">
            {{ $prevLevel := 1 }}
              {{ range $i, $header := $headers }}
                {{ $genAnchor := index (split (index (split $header "id=\"") 1) "\"") 0 }}
                {{ $anchorID := $genAnchor }}
                {{ $level := index (findRE "<h([1-6])" $header 1) 0 | replaceRE "<h([1-6])" "$1" | int }}
                {{ if gt $level $prevLevel }}
                  <ul>
                {{ else if lt $level $prevLevel }}
                  <!-- Close the previous list(s) if this header is shallower -->
                  {{ range seq (sub $prevLevel $level) }}</ul></li>{{ end }}
                {{ else if gt $i 0 }}
                  <!-- Close previous list item -->
                  </li>
                {{ end }}
                <!-- Extract text content, excluding the header link icon -->
                {{ $headerText := $header | replaceRE `<a[^>]*class="header-link"[^>]*>.*?</a>` "" | plainify | safeHTML }}
                <li><a href="#{{ $anchorID }}">{{ $headerText }}</a>
                {{ $prevLevel = $level }}
              {{ end }}
              <!-- Close remaining open lists -->
              {{ range seq (sub $prevLevel 1) }}</ul></li>{{ end }}
          </nav>
        </nav>
      <!-- Use Hugo's .TableOfContents by default -->
      {{ else if gt (len .) 32 }}
        <h2 class="font-medium my-3">On this page</h2>
        <nav class="text-slate-700">
          {{ . }}
        </nav>
        {{ end }}
    </div>
  </section>
{{ end }}