WordPress sidebar navigation based off of top-level parent page - php

Question

I'm trying to create a complex sidebar navigation system that remains the same depending on what top-level page you're viewing. For example, say I have this navigation:
Home
About
Our Company
Location
Hours
Our PeopleJim
Dave
Sarah
Kelly
PortfolioLogos
Websites
Contact
Now, if the user was anywhere within the About section, I'd want the sidebar to display:
About
Our Company
Location
Hours
Our PeopleJim
Dave
Sarah
Kelly
That goes for if they're in the main About page, in the Our Company page, or in the Location page. I need the whole navigation visible regardless of depth.
If the user was in a page with no sub-items, such as Contact, the sidebar needs to show:
Home
About
Portfolio
Contact
What's more, the ordering needs to be based on a WordPress Menu (one main menu, each sidebar can't be it's own; that's too complicated for the user). I don't know if that complicates things or not.
In the past, I've managed to get something to display children and sibling pages, but it doesn't display parent pages, and doesn't display in the order that the user defines.
<ul>
<?
global $wp_query;
if( empty($wp_query->post->post_parent) ) {
$parent = $wp_query->post->ID;
}
else {
$parent = $wp_query->post->post_parent;
}
wp_list_pages ("&title_li=&child_of=$parent");
?>
</ul>
If this can be modified to work the way I want it, that'd be great. I'm going to try and figure this out on my own, and will post updates as I make progress.
UPDATE 1: I've made a bit of progress determining what the absolute parent is. I think I'm on the right track.
<?
if ($post->post_parent) {
$ancestors = get_post_ancestors($post->ID);
$root = count($ancestors)-1;
$parent = $ancestors[$root];
} else {
$parent = $post->ID;
}
echo "Current Page: " . $post->ID . "<br />";
echo "Top Level Parent: " . $parent;
?>
UPDATE 2: I can now determine the correct page ID to query for a menu, so I think I'm getting close.
<?
$children = get_pages("child_of=".$post->ID);
if ($post->post_parent) {
$ancestors = get_post_ancestors($post->ID);
$root = count($ancestors)-1;
$parent = $ancestors[$root];
} elseif (count($children) != 0) {
$parent = $post->ID;
} else {
$parent = 0;
}
echo "Current Page: " . $post->ID . "<br />";
echo "Top Level Parent: " . $parent;
?>
UPDATE 3: I'm nearly there! The only problem is this uses the page's order from the editor, not from the menu. Is it possible to edit this to work with a menu instead?
<aside>
<?
$children = get_pages("child_of=".$post->ID);
if ($post->post_parent) {
$ancestors = get_post_ancestors($post->ID);
$root = count($ancestors)-1;
$parent = $ancestors[$root];
$sidebarDepth = 0;
$postParentID = get_post($parent);
$title = $postParentID->post_title;
} elseif (count($children) != 0) {
$parent = $post->ID;
$sidebarDepth = 0;
$postParentID = get_post($parent);
$title = $postParentID->post_title;
} else {
$parent = 0;
$sidebarDepth = 1;
$frontPageID = get_option("page_on_front");
$exclude = $frontPageID;
$postParentID = get_post($frontPageID);
$title = $postParentID->post_title;
}
?>
<header>
<h6><? echo $title ?> »</h6>
</header>
<section>
<nav>
<?
echo "<ul>";
wp_list_pages("child_of=" . $parent . "&depth=" . $sidebarDepth . "&exclude=" . $exclude . "&title_li=&");
echo "</ul>";
?>
</nav>
</section>
</aside>

Answer 1

Figured it out! I modified the code from this answer to add a start_in option to wp_nav_menu, and modified my code from there. Now this works exactly as I wanted it.
In functions.php:
// add start_in argument to navigation
add_filter("wp_nav_menu_objects",'my_wp_nav_menu_objects_start_in',10,2);
function my_wp_nav_menu_objects_start_in( $sorted_menu_items, $args ) {
if (isset($args->start_in) && $args->start_in != 0) {
$menu_item_parents = array();
foreach ($sorted_menu_items as $key => $item) {
if ($item->object_id == (int)$args->start_in) $menu_item_parents[] = $item->ID;
if (in_array($item->menu_item_parent, $menu_item_parents)) {
$menu_item_parents[] = $item->ID;
} else {
unset($sorted_menu_items[$key]);
}
}
return $sorted_menu_items;
} else {
return $sorted_menu_items;
}
}
In page.php (or whatever template you want):
<aside>
<?
if ($post->post_parent) {
$ancestors = get_post_ancestors($post->ID);
$root = count($ancestors)-1;
$parent = $ancestors[$root];
} elseif (count(get_pages("child_of=".$post->ID)) != 0) {
$parent = $post->ID;
} else {
$parent = get_option("page_on_front");
$sidebarDepth = 1;
$exclude = $parent;
}
if ($post->post_parent || count(get_pages("child_of=".$post->ID)) != 0) {
$sidebarDepth = 0;
$start_in = $parent;
$depth = 0;
} else {
$depth = 1;
$start_in = 0;
}
$parentID = get_post($parent);
$parentTitle = $parentID->post_title;
$parentURL = get_permalink($parentID);
?>
<header>
<h6><? echo $parentTitle ?> »</h6>
</header>
<section>
<nav>
<?
wp_nav_menu(
array(
"container" => false,
"depth" => $depth,
"items_wrap" => '<ul>%3$s</ul>',
"start_in" => $start_in,
"theme_location" => "first"
)
);
?>
</nav>
</section>
</aside>