{%- assign nav_pages = site.html_pages

| where_exp: "item", "item.title != nil"

| where_exp: "item", "item.nav_exclude != true" -%}

{%- assign nav_top_nodes = nav_pages

| where_exp: "item", "item.parent == nil" -%}

{%- include components/nav/sorted.html pages=nav_top_nodes -%}

{%- assign pager_pages = "" | split: "" -%}

{%- for top_node in nav_sorted -%}

{%- assign pager_pages = pager_pages | push: top_node -%}

{%- assign child_pages = nav_pages | where: "parent", top_node.title -%}

{%- include components/nav/sorted.html pages=child_pages -%}

{%- assign child_pages = nav_sorted -%}

{%- if top_node.child_nav_order == 'desc' or top_node.child_nav_order == 'reversed' -%}

{%- assign child_pages = child_pages | reverse -%}

{%- endif -%}

{%- for child_page in child_pages -%}

{%- assign pager_pages = pager_pages | push: child_page -%}

{%- assign grandchild_pages = nav_pages | where: "parent", child_page.title -%}

{%- include components/nav/sorted.html pages=grandchild_pages -%}

{%- assign grandchild_pages = nav_sorted -%}

{%- if child_page.child_nav_order == 'desc' or child_page.child_nav_order == 'reversed' -%}

{%- assign grandchild_pages = grandchild_pages | reverse -%}

{%- endif -%}

{%- assign pager_pages = pager_pages | concat: grandchild_pages -%}

{%- endfor -%}

{%- endfor -%}

{%- assign current_index = -1 -%}

{%- for pager_page in pager_pages -%}

{%- if pager_page.url == page.url -%}

{%- assign current_index = forloop.index0 -%}

{%- break -%}

{%- endif -%}

{%- endfor -%}

{%- if current_index >= 0 -%}

{%- assign previous_page = nil -%}

{%- assign next_page = nil -%}

{%- assign current_children = nav_pages | where: "parent", page.title | sort_natural: "title" | sort: "nav_order" -%}

{%- if current_index > 0 -%}

{%- assign previous_index = current_index | minus: 1 -%}

{%- assign previous_page = pager_pages[previous_index] -%}

{%- endif -%}

{%- assign pager_count = pager_pages | size -%}

{%- assign last_index = pager_count | minus: 1 -%}

{%- if current_index < last_index -%}

{%- assign next_index = current_index | plus: 1 -%}

{%- assign next_page = pager_pages[next_index] -%}

{%- endif -%}

{%- if page.has_children and current_children.size > 0 -%}

{%- assign next_page = current_children.first -%}

{%- endif -%}

{%- if previous_page or next_page -%}

<nav class="page-nav" aria-label="Page navigation">

{%- if previous_page -%}

<a class="page-nav-link page-nav-link-prev" href="{{ previous_page.url | relative_url }}">

<span class="page-nav-label">Previous</span>

<span class="page-nav-title">{{ previous_page.title }}</span>

</a>

{%- else -%}

<span></span>

{%- endif -%}

{%- if next_page -%}

<a class="page-nav-link page-nav-link-next" href="{{ next_page.url | relative_url }}">

<span class="page-nav-label">Next</span>

<span class="page-nav-title">{{ next_page.title }}</span>

</a>

{%- endif -%}

</nav>

{%- endif -%}

{%- endif -%}