{% comment %}
  Sorts videos based on the video_number property and optionally filters them.

  Parameters:
    videos Video[]              Array of videos that will be sorted.
    sortByDate bool             Wether to sort the videos by date (default: false).
    reverse bool                Wether to reverse the order in which videos are storedin the array (default: false).
    future bool                 Wether to include future videos (default: false).
    [1.1] seriesPath string     The series path by which the videos will be filtered.
    [1.2] seriesPage string     The series page by which the videos will be filtered.

  Returns:
    out_sortedVideos Video[]    Array of sorted videos.
{% endcomment %}


{% comment %} Filter by the given series path. {% endcomment %}
{% if include.seriesPath %}
  {% assign int_seriesPath = include.series_path %}

{% comment %} Filter by the series path extracted from the given series page. {% endcomment %}
{% elsif include.seriesPage %}
  {% assign int_seriesPath = include.seriesPage.path | remove: '/index.md' %}

{% comment %} Don't use any filters. {% endcomment %}
{% else %}
  {% assign int_seriesPath = '' %}
{% endif %}

{% comment %} Filter videos by series path (only if necessary). {% endcomment %}
{% assign int_videos = include.videos | where_exp: 'video', 'video.path contains int_seriesPath' %}

{% comment %} Remove future videos and videos that aren't linked to YouTube if they shouldn't be included. {% endcomment %}
{% unless include.future %}
  {% assign int_videos = int_videos | where_exp: 'video', 'video.date <= site.time'
                                    | where_exp: 'video', 'video.video_id' %}
{% endunless %}

{% if int_videos.size > 0 %}

  {% comment %} Filter out the index pages. {% endcomment %}
  {% if include.sortByDate %}
    {% assign out_sortedVideos = int_videos | where: 'layout', 'video' | sort: 'date' %}
  {% else %}
    {% assign out_sortedVideos = int_videos | where: 'layout', 'video' | sort: 'video_number' %}
  {% endif %}

  {% comment %} Reverse video order if include.reverse is set to true. {% endcomment %}
  {% if include.reverse %}
    {% assign out_sortedVideos = out_sortedVideos | reverse %}
  {% endif %}

{% endif %}