Add photoswipe

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

layouts/partials/head/opengraph.html

@@ -0,0 +1,80 @@
+<meta property="og:title" content="{{ .Title }}" />
+<meta
+  property="og:description"
+  content="{{- with .Description -}}
+    {{- . -}}
+  {{- else -}}
+    {{- if .IsPage -}}
+      {{- with .Site.Params.description -}}{{- . -}}{{- end -}}
+    {{- end -}}
+  {{- end -}}"
+/>
+<meta
+  property="og:type"
+  content="{{- if .IsPage -}}
+    article
+  {{- else -}}
+    website
+  {{- end -}}"
+/>
+<meta property="og:url" content="{{- .Permalink -}}" />
+
+{{ with .Params.image }}
+  {{ $image := $.Resources.GetMatch . }}
+  {{ with $image }}
+    {{ $thumb := .Resize "400x" }}
+    <meta property="og:image" content="{{- $thumb.Permalink -}}" />
+  {{ end }}
+{{ end }}
+
+{{ $iso8601 := "2000-01-01T00:00:00-01:00" }}
+{{ if .IsPage }}
+  {{ if not .PublishDate.IsZero }}
+    <meta
+      property="article:published_time"
+      {{ .PublishDate.Format $iso8601 | printf "content=%q" | safeHTMLAttr }}
+    />
+  {{ else if not .Date.IsZero }}
+    <meta
+      property="article:published_time"
+      {{ .Date.Format $iso8601 | printf "content=%q" | safeHTMLAttr }}
+    />
+  {{ end }}
+{{ end }}
+{{/* .IsPage */}}
+
+{{ with .Params.audio }}
+  <meta property="og:audio" content="{{- . -}}" />
+{{ end }}
+{{ with .Params.locale }}
+  <meta property="og:locale" content="{{- . -}}" />
+{{ end }}
+{{ with .Site.Params.title }}
+  <meta property="og:site_name" content="{{- . -}}" />
+{{ end }}
+{{ with .Params.videos }}
+  {{ range . }}
+    <meta property="og:video" content="{{- . | absURL -}}" />
+  {{ end }}
+{{ end }}
+
+{{ $permalink := .Permalink }}
+{{ $siteSeries := .Site.Taxonomies.series }}{{ with .Params.series }}
+  {{ range $name := . }}
+    {{ $series := index $siteSeries $name }}
+    {{ range $page := first 6 $series.Pages }}
+      {{ if ne $page.Permalink $permalink }}
+        <meta property="og:see_also" content="{{- $page.Permalink -}}" />
+      {{ end }}
+    {{ end }}
+  {{ end }}
+{{ end }}
+
+{{ if .IsPage }}
+  <meta property="article:section" content="{{- .Section -}}" />
+  {{ with .Params.tags }}
+    {{ range . }}
+      <meta property="article:tag" content="{{- . -}}" />
+    {{ end }}
+  {{ end }}
+{{ end }}