New Module: Structure - Uses entries to create a page hierarchy for static and listing pages

function nav_main() {
    global $DB, $IN, $PREFS;
    
    // get site pages data
    $site_pages = $PREFS->core_ini['site_pages'];
    // get current uri path
    $uri = $IN->URI;
    // get current entry id
    $entry_id = array_search("/", $site_pages['uris']);
    // get node of the current entry
    $node = 0; //$start_node = $entry_id ? $this->nset->getNode($entry_id) : false;
    
    // node does not have any structure data we return nothing to prevent errors
    if ($node === false && ! $entry_id) {
        return '';
    }
    
    // if we have an entry id but no node, we have listing entry
    if ($entry_id && ! $node) {
        // get entry's parent id
        $pid = $this->get_pid_for_listing_entry($entry_id);
        
        // get node of parent entry
        // because we will be showing nav sub from its view point
        $node = $start_node = $this->nset->getNode($pid);
    }
        
    // if we are on a root that is a leaf
    // no sub nav to return
    if ($node && $node['isLeaf'] && $node['depth'] == 0) {
        return '';
    }
    
    if ($node['isLeaf'] && $node['depth'] > 1) {
        // we are on a child leaf past the root level
        // so we use the parent as the starting point for the sub nav
        $start_node = $this->nset->getNode($node['parent_id']);
    }
    //print_r($start_node);die;
    
    // get siblings
    $where = 'node.parent_id = ' . ($start_node['depth'] ? $start_node['parent_id'] : $start_node['id']);
    // get children
    $where .= ' OR node.parent_id = ' . $start_node['id'];
    
    $entry_depth = $start_node['depth'] ? $start_node['depth'] : 1;
    
    // get structure data from DB            
    $sql = "SELECT node.*, 
                (COUNT(parent.entry_id) - 1) AS depth, 
                ((COUNT(parent.entry_id) - 1) - $entry_depth) AS subDepth, 
                if((node.rgt - node.lft) = 1,1,0) AS isLeaf, 
                expt.title 
            FROM exp_structure AS node
            INNER JOIN exp_structure AS parent 
                ON node.lft BETWEEN parent.lft AND parent.rgt 
            INNER JOIN exp_weblog_titles AS expt 
                ON node.entry_id = expt.entry_id
            WHERE parent.lft > 1 
            GROUP BY node.entry_id 
            ORDER BY node.lft";
    $result = $DB->query($sql);
    
    // check how many entries at subDepth 0
    $num = 0;
    foreach ($result->result as $entry) {
        if ($entry['subDepth'] == 0) {
            $num++;
        }
    }
    // if we only have 1 subDepth 0 entry and it has children
    // then we just show the children
    if ($num === 1 && $result->num_rows > 1) {
        unset($result->result[0]);
        foreach ($result->result as &$entry) {
            $entry['subDepth'] -= 1;
        }
    }
    
        $html = '<ul id="nav_main">';
    $prev_subDepth = false;
    $ul_open       = false;
    $i= 0;
    foreach ($result->result as $entry) {    
        if($prev_subDepth == $entry["subDepth"]  AND $prev_subDepth != false){
            $html .= "</li>";
        }
        
        if($entry["subDepth"]  > $prev_subDepth  and $i >0){
            $html .= '<ul>';
        }
        
        if($entry["subDepth"]  < $prev_subDepth  and $i >0){
            $x = $prev_subDepth - $entry["subDepth"];
            for($y=0;$y<$x;$y++){
                $html .= '</li></ul>';
            }
        }
        
        // out entry uri of this loop instance
        $euri = $site_pages['uris'][$entry['entry_id']];
        // current page's parent uri
        $puri = $node['parent_id'] ? $site_pages['uris'][$node['parent_id']] : '';
        
        $here = '';
        if ($euri === $puri) {
            $here = ' parent_here';
        } else if ($uri === $euri) {
            $here = ' here';
        }
        
        $html .= '<li class="sub_level_' . $entry['subDepth'] . $here . '">';
        $html .= '<a href="http://">' . $entry['title'];_        $html .= '</a>';
        
        $prev_subDepth = (int)$entry['subDepth'];
        $i++;
    }
    $html .= '</ul>';
    //$html .= '<pre>' . $sql . '</pre>

<p>’;
    return $html;
}

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