{{ $page := .Page }}

{{ $thumbnails := slice }}
{{ with $thumbnailNamesList := $page.Params "thumbnails" }}
  {{/* Specify a list of thumbnails to use with the page "thumbnails" param */}}
  {{ range $thumbnailNamesList }}
    {{ with $page.Resources.GetMatch . }}
      {{ $thumbnails = $thumbnails | append . }}
    {{ else }}
      {{ errorf "No image resources available for %s from thumbnails param" . }}
    {{ end }}
  {{ end }}
{{ else }}
  {{/* Get a list of all the image resources and see if any of them specify
       thumbnails for themselves. If they do, use those, otherwise use the image
       resource itself. */}}
  {{ range $img := $page.Resources.ByType "image" }}
    {{ with $thumbnailResourceName := $img.params.thumbnail }}
      {{ with $page.Resources.GetMatch $thumbnailResourceName }}
        {{ $thumbnails = $thumbnails | append . }}
      {{ else }}
        {{ errorf "No image resources available for '%s' from thumbnail param for image resources %s"
            $thumbnailResourceName
            $img.Name }}
      {{ end }}
    {{ else }}
      {{/* TODO: Look for a named image that indicates it's a thumbnail of 
           another resources. Something like ${imgBasename}_thumbnail.${ext}.
           I don't know how easy Hugo makes filename processing, so this could 
           be painful. */}}
      {{ $thumbnails = $thumbnails | append $img }}
    {{ end }}
  {{ end }}
{{ end }}

{{ if eq (len $thumbnails) 0 }}
  {{ errorf "Couldn't find any thumbnails for %s" $page.Permalink }}
{{ end }}

{{ $thumbnailOptions := dict }}
{{ if isset . "Width" }}{{ $thumbnailOptions = $thumbnailOptions | merge (dict "Width" .Width) }}{{ end }}
{{ if isset . "Height" }}{{ $thumbnailOptions = $thumbnailOptions | merge (dict "Height" .Height) }}{{ end }}

{{ $processedThumbnails := slice }}
{{ range $thumbnails }}
  {{ $options := $thumbnailOptions | merge "Image" . }}
  {{ $processedThumbnail := partial "photos/thumbnail_for_list.html" $options }}
  {{ $processedThumbnails = $processedThumbnails | append $processedThumbnail }}
{{ end }}

{{ return $processedThumbnails }}