{{- /* Render one link button.
       Context dict: { "link": {title,url,icon,image,featured,startDate,endDate,rel,note,...}, "analytics": params.analytics }
       Reads ONLY from its dict argument (per docs/code-standards.md partial composition rule). */ -}}
{{- $l := .link -}}
{{- $a := .analytics -}}
{{- /* Per-link visibility window: skip rendering when now < startDate or now > endDate.
       Build-time evaluation only — re-evaluated at next site rebuild. */ -}}
{{- $now := now -}}
{{- $startOk := true -}}
{{- $endOk := true -}}
{{- with $l.startDate }}{{ $startOk = ge $now (time .) }}{{ end -}}
{{- with $l.endDate }}{{ $endOk = le $now (time .) }}{{ end -}}
{{- if and $startOk $endOk -}}
{{- $title := $l.title -}}
{{- $url := $l.url -}}
{{- $icon := $l.icon -}}
{{- $image := $l.image -}}
{{- $note := $l.note -}}
{{- $external := strings.HasPrefix $url "http" -}}
{{- /* Class composition: .link + optional .link--featured */ -}}
{{- $classes := "link" -}}
{{- if $l.featured }}{{ $classes = printf "%s link--featured" $classes }}{{ end -}}
{{- /* rel value for external links: always start with safe defaults, then append user rel */ -}}
{{- $rel := "noopener noreferrer" -}}
{{- with $l.rel }}{{ $rel = printf "%s %s" $rel . }}{{ end -}}
{{- /* GA4 click-tracking attr: emit only when analytics enabled (caller passes the resolved dict). */ -}}
{{- $trackClicks := and $a $a.measurementId (ne ($a.trackClicks | default true) false) -}}
{{- /* UTM injection at build time for external links. Splits #fragment first so the
       query string lands BEFORE the fragment (preserving link semantics). */ -}}
{{- if and $external $a $a.utmSource -}}
  {{- $fragment := "" -}}
  {{- if strings.Contains $url "#" -}}
    {{- $bits := split $url "#" -}}
    {{- $url = index $bits 0 -}}
    {{- $fragment = printf "#%s" (index $bits 1) -}}
  {{- end -}}
  {{- $sep := cond (strings.Contains $url "?") "&" "?" -}}
  {{- $utm := printf "utm_source=%s&utm_medium=%s" (urlquery $a.utmSource) (urlquery ($a.utmMedium | default "bio")) -}}
  {{- with $a.utmCampaign }}{{ $utm = printf "%s&utm_campaign=%s" $utm (urlquery .) }}{{ end -}}
  {{- $url = printf "%s%s%s%s" $url $sep $utm $fragment -}}
{{- end -}}
<a class="{{ $classes }}"
   href="{{ $url }}"
   {{- if $external }} target="_blank" rel="{{ $rel }}"{{ end -}}
   {{- if $trackClicks }} data-analytics-event="link:{{ $l.title | urlize }}"{{ end }}>
  {{- if $image -}}
  <img class="link__thumb" src="{{ $image | strings.TrimPrefix "/" | relURL }}" alt="" width="24" height="24" loading="lazy" decoding="async" />
  {{- else if $icon -}}
  <span class="link__icon" aria-hidden="true">{{ partial "icon.html" $icon }}</span>
  {{- end }}
  <span class="link__title">
    {{- $title -}}
    {{- with $note }}<span class="link__note">{{ . }}</span>{{- end -}}
  </span>
</a>
{{- end -}}