{% comment %}
  This code generates links to the previous/next video in the collection sorted by the 'video_number' property.
  page.previous/page.next doesn't work since jekyll always (at the time of developing this site) sorts collections by date.
  Code adapted from budparr (https://gist.github.com/budparr/3e637e575471401d01ec).

  Parameters:
    videos Video[]            Array of sorted videos.
    currentVideo Video        The current video.

  Returns:
    out_previousVideo Video   The page of the previous video.
    out_nextVideo Video       The page of the next video.
{% endcomment %}


{% comment %} Create variables for previous and next video. {% endcomment %}
{% assign out_previousVideo = null %}
{% assign out_nextVideo = null %}

{% comment %} For all videos ... {% endcomment %}
{% for int_video in include.videos %}

  {% comment %} ... find this video ... {% endcomment %}
  {% if int_video.id == include.currentVideo.id %}

    {% comment %} ... save the next video if it exists ... {% endcomment %}
    {% unless forloop.last %}
      {% assign out_nextVideo = include.videos[forloop.index] %}
    {% endunless %}

    {% comment %} ... and leave the loop. {% endcomment %}
    {% break %}

  {% endif %}

  {% comment %} This video might be the previous video, so keep a reference. {% endcomment %}
  {% assign out_previousVideo = int_video %}
{% endfor %}