{% comment %}
  Renders the leading icons of a post, from its `title_icons` front matter:

    title_icons:         # the icons themselves, in display order
      - 📗
      - 👨🏽‍🏫
    title_icons_count:   # how many icons each surface shows; 0 hides them
      homepages: 2
      opened: 2
      recommended: 0
      related: 0
      title: 1

  Each `title_icons_count` value is a count taken from the front of the list, so
  one surface can show fewer icons than another. Zero hides them there.

  Counts are a separate key from the list on purpose: Jekyll merges front-matter
  defaults shallowly, so had they been nested inside `title_icons`, any page
  declaring its own list would wipe out the counts inherited from _config.yml.

  Site-wide counts are set for every page through `defaults` in _config.yml; a
  page may override them in its own front matter. A surface left unset shows
  every icon in the list.

  Parameters:
    post    - the post object whose icons to render (`page` on a post page)
    context - the surface asking:
              homepages | opened | recommended | related | title
    plain   - truthy to emit bare text plus a trailing space instead of the
              <span> wrapper. Required inside <title>, which takes no markup.

  Surfaces:
    homepages   - the post list on the home page
    opened      - the title of the opened post itself
    recommended - the featured/pinned posts panel in the right sidebar
    related     - the "related posts" cards at the bottom of a post
    title       - the <title> element, i.e. the browser tab / bookmark label
{% endcomment %}
{%- assign icon_list = include.post.title_icons -%}
{%- if icon_list and icon_list.size > 0 -%}

  {%- comment -%} Per-post count wins; `== nil` keeps an explicit 0 usable. {%- endcomment -%}
  {%- assign count = include.post.title_icons_count[include.context] -%}
  {%- if count == nil -%}
    {%- assign count = icon_list.size -%}
  {%- endif -%}

  {%- if count > 0 -%}
    {%- comment -%} `join` rather than a loop with a literal space: Liquid's
        whitespace control swallowed the separator, gluing the icons together.
        {%- endcomment -%}
    {%- assign shown_icons = icon_list | slice: 0, count -%}
    {%- assign icons_text = shown_icons | join: ' ' -%}
    {%- comment -%} <title> takes no markup, so `plain` skips the wrapper and
        carries its own trailing space (the span gets its gap from CSS instead,
        which survives the production whitespace stripping). {%- endcomment -%}
    {%- if include.plain -%}{{ icons_text }} {% else %}<span class="post-icons">{{ icons_text }}</span>{%- endif -%}
  {%- endif -%}

{%- endif -%}