{{/*
    Get the first regular page for a given section recursivelly respecting
    the ordering of each intermediate section.

    Expects a section -- NOT A REGULAR PAGE -- to be given as argument, will raise an
    error otherwise.

    Returns a regular page. If none can be found, raises an error.

    Example usages from a regular page:
    - Last page of comic : {{ partial "func/FirstPageRecursive.html" .FirstSection }}
    - Last page of chapter : {{ partial "func/FirstPageRecursive.html" .Parent }}
*/}}

{{/*
    As a note: using `index .FirstSection.RegularPagesRecursive 0` would be unsafe.

    RegularPagesRecursive uses the default sort order on all found pages
    regardless of parent pages.

    Given the following pages, weight and title :

    - comic/
        - chapter_1/:
            - page_1 (weight 10, title "Prologue - Page 1")
            - page_2 (weight 20, title "Prologue - Page 2")
            - ...
        - ...
        - chapter_7/:
            - page_1 (weight 10, title "Ending - Page 1")
            - page_2 (weight 20, title "Ending - Page 2")

    Using `index .FirstSection.RegularPagesRecursive 0` would give chapter_7/page_1 as first page!

    Hugo's ordering is done by *weight* asc., then *date* desc., then *title* asc.,
    then *path* asc..

    Thus, final order would be :
    - chapter_2/page_1: weight 10, title "Ending - Page 1"   - because 10 = 10 and E < P
    - chapter_1/page_1: weight 10, title "Prologue - Page 1" - because 10 < 20
    - chapter_2/page_2: weight 20, title "Ending - Page 2"   - because 20 = 20 and E < P
    - chapter_1/page_2: weight 20, title "Prologue - Page 2"
*/}}

{{ if .IsPage }}
    {{ errorf "'func/FirstPageRecursive' page argument must be a section, not a regular page" }}
{{ end }}

{{ if eq .Pages.Len 0 }}
    {{ errorf "Section '%s' contains no pages!" .Path }}
{{ end }}

{{ $first_page := index .Pages 0 }}

{{ if $first_page.IsSection }}
    {{ $first_page = partial "func/FirstPageRecursive.html" $first_page }}
{{ end }}

{{ return $first_page }}