{% comment %}
  Tries to find the series object for this video.
  If a series object is passed in, it finds the parent series.
  
  Parameters:
    video Video|Series    The video object.

  Returns:
    out_series Series?    The series object.
{% endcomment %}


{% comment %} Split the video path to ... {% endcomment %}
{% assign int_videoPathComponents = include.video.path | split: '/' %}

{% comment %} ... extract the file name. {% endcomment %}
{% assign int_videoFileName = int_videoPathComponents | last %}

{% comment %} Use the parent series if the passed object is already a series. {% endcomment %}
{% if int_videoFileName == 'index.md' %}
  {% assign seriesName = int_videoPathComponents | pop | last %}
  {% assign int_videoFileName = int_videoFileName | prepend: '/' | prepend: seriesName %}
{% endif %}

{% comment %} Find the series path. {% endcomment %}
{% assign int_seriesPath = include.video.path | remove: int_videoFileName | append: 'index.md' %}

{% comment %} Count the path's slashes (a.k.a nesting level) ... {% endcomment %}
{% assign int_seriesPathSlashCount = int_seriesPath | split: '/' | size %}
{% if int_seriesPathSlashCount > 2 %}

  {% comment %} ... and return the series object if if the path leads to a series. {% endcomment %}
  {% assign out_series = site[include.video.collection] | where: 'path', int_seriesPath | first %}
{% else %}
  {% assign out_series = null %}
{% endif %}