How do I check if a structure has any entries at level 3 when I'm at level 1?

Question

I'd like to output a special link in level 1 upon current top-level entry doesn't have any entries at level 3. If It have move that special link one level above.

To picture it:

• Page 1
  • Subpage 1
  • Subpage 2
  • Special link A
• Page 2
  • Subpage 1
    • Subpage 1.1
    • Special link A

Currently I didn't have any difficulties with level 2:

{% set lvl = entry.level %} 
{% if lvl == 2 and entry.children|length %}
    A link
{% endif %}

To set that special link at level 1 is. Most logical way to me is to use EntryModel's method getDescendants( distance ) as I don't have to set any variable. If I understand it correctly It should get descendant entries at given level? of a current entry's variable. When I set to (distance) other integer than 1 let's say 2 It prints out all entries from second level including level 2. So It's unclear to me what distance does in this case.

{% if lvl == 1 and entry.getDescendants(2)|length %}
    A link
{% endif %}

Argument is true even if there are no descendant entries of second level. Because When looping in It prints all entries from second level up including second level as I mentioned before.

Or I can't use this method?

Answer 1

To make it works I had to query in the section for descendant entries at level 3 of a current entry variable.

{% set products = craft.entries.section('products') %}

{% if lvl == 1 and products.descendantOf(entry).level(3).first()|length %}
    // If the above statment is true we don't want that special link at level 1
{% elseif lvl == 1 %}
    // A special link
{% endif %}


{% if lvl == 2 and entry.children|length %}
    // A special link
{% endif %}

I welcome a smarter solution.

Updated: Thanks to @carlcs comment a performance has been enhanced

{% if lvl == 1 and products.descendantOf(entry).level(3).total() > 0 %}
    // If the above statment is true we don't want that special link at level 1
{% elseif lvl == 1 %}
    // A special link
{% endif %}


{% if lvl == 2 and entry.children.total() > 0 %}
    // A special link
{% endif %}