{{ $filetreeLevel := 0 }}

{{ define "_filetreeLevelUpOpen" }}
   {{ if gt .Level $filetreeLevel }}
      <details>
      {{ $filetreeLevel = $filetreeLevel + 1 }}
      {{ template "_filetreeLevelUpOpen" . }}
   {{ end }}
{{ end }}

{{ define "_filetreeCloseAll" }}
   {{ if lt 0 $filetreeLevel }}
      </details>
      {{ $filetreeLevel = $filetreeLevel - 1 }}
      {{ template "_filetreeCloseAll" . }}
   {{ end }}
{{ end }}

{{ define "_filetreeLevelDownOpen" }}
   {{ if lt .Level $filetreeLevel }}
      </details>
      {{ $filetreeLevel = $filetreeLevel - 1 }}
      {{ template "_filetreeLevelDownOpen" . }}
   {{ end }}
{{ end }}

{{ define "_filetreeRecurse" }}
   <plaintext>
   {{ range . }}
      {{ template "_filetreeLevelUpOpen" . }}
      {{ template "_filetreeLevelDownOpen" . }}
         <details>
            <summary>
               <a href="/files/{{ .ID }}">{{ .Title }}</a>
            </summary>
   {{ end }}
   {{ template "_filetreeLevelDownOpen" . }}
{{ end }}

{{ define "_filetree" }}
input = {{ . }}
<div>
   {{ template "_filetreeRecurse" .Tree }}
</div>
{{ end }}