Previous Next Links for Jekyll Collections - with wrap around to beginning link and last link when needed

jekyll-collections-prev-next-wrap-around.html

{% capture the_collection %}{{page.collection}}{% endcapture %}
{% if page.collection %}
  {% assign  document = site[the_collection]  %}
{% endif %}
<h1>TITLE: {{ page.title }}</h1>
{% for links in document  %}
{% if forloop.first %}
	{% assign first = links %}
{% endif %}
{% if forloop.last %}
	{% assign last = links %}
{% endif %}
  {% if links.title == page.title %}
	{% unless forloop.first %}
		{% assign prevurl = prev.url %}
	{% endunless %}
	{% unless forloop.last %}
		{% assign next = document[forloop.index] %}
		{% assign nexturl = next.url %}
	{% endunless %}
  {% endif %}
  {% assign prev = links %}
{% endfor %}

{% assign firsturl = first.url %}
{% assign lasturl = last.url %}

{% if prevurl %}<a href="{{prevurl}}" class="prev">Prev</a>{% else %}<a href="{{lasturl}}" class="prev">Prev</a>{% endif %}<br />

{% if nexturl %}<a href="{{nexturl}}" class="nxt">Next</a>{% else %}<a href="{{firsturl}}" class="prev">Next</a>{% endif %}