ElggMenuBuilder.php

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<?php
class ElggMenuBuilder {

    protected $menu = array();

    protected $selected = null;

    public function __construct(array $menu) {
        $this->menu = $menu;
    }

    public function getMenu($sort_by = 'text') {

        $this->selectFromContext();

        $this->selected = $this->findSelected();

        $this->setupSections();

        $this->setupTrees();

        $this->sort($sort_by);

        return $this->menu;
    }

    public function getSelected() {
        return $this->selected;
    }

    protected function selectFromContext() {
        if (!isset($this->menu)) {
            $this->menu = array();
            return;
        }

        // get menu items for this context
        $selected_menu = array();
        foreach ($this->menu as $menu_item) {
            if (!is_object($menu_item)) {
                _elgg_services()->logger->error("A non-object was passed to \ElggMenuBuilder");
                continue;
            }
            if ($menu_item->inContext()) {
                $selected_menu[] = $menu_item;
            }
        }

        $this->menu = $selected_menu;
    }

    protected function setupSections() {
        $sectioned_menu = array();
        foreach ($this->menu as $menu_item) {
            if (!isset($sectioned_menu[$menu_item->getSection()])) {
                $sectioned_menu[$menu_item->getSection()] = array();
            }
            $sectioned_menu[$menu_item->getSection()][] = $menu_item;
        }
        $this->menu = $sectioned_menu;
    }

    protected function setupTrees() {
        $menu_tree = array();

        foreach ($this->menu as $key => $section) {
            $parents = array();
            $children = array();
            $all_menu_items = array();
            
            // divide base nodes from children
            foreach ($section as $menu_item) {
                /* @var \ElggMenuItem $menu_item */
                $parent_name = $menu_item->getParentName();
                $menu_item_name = $menu_item->getName();
                
                if (!$parent_name) {
                    // no parents so top level menu items
                    $parents[$menu_item_name] = $menu_item;
                } else {
                    $children[$menu_item_name] = $menu_item;
                }
                
                $all_menu_items[$menu_item_name] = $menu_item;
            } 
            
            if (empty($all_menu_items)) {
                // empty sections can be skipped
                continue;
            }
                        
            if (empty($parents)) {
                // menu items without parents? That is sad.. report to the log
                $message = _elgg_services()->translator->translate('ElggMenuBuilder:Trees:NoParents');
                _elgg_services()->logger->notice($message);
                
                // skip section as without parents menu can not be drawn
                continue;
            }
                        
            foreach ($children as $menu_item_name => $menu_item) {
                $parent_name = $menu_item->getParentName();
                                
                if (!array_key_exists($parent_name, $all_menu_items)) {
                    // orphaned child, inform authorities and skip to next item
                    $message = _elgg_services()->translator->translate('ElggMenuBuilder:Trees:OrphanedChild', array($menu_item_name, $parent_name));
                    _elgg_services()->logger->notice($message);
                    
                    continue;
                }
                
                if (!in_array($menu_item, $all_menu_items[$parent_name]->getData('children'))) {
                    $all_menu_items[$parent_name]->addChild($menu_item);
                    $menu_item->setParent($all_menu_items[$parent_name]);
                } else {
                    // menu item already existed in parents children, report the duplicate registration
                    $message = _elgg_services()->translator->translate('ElggMenuBuilder:Trees:DuplicateChild', array($menu_item_name));
                    _elgg_services()->logger->notice($message);
                    
                    continue;
                }
            }

            // convert keys to indexes for first level of tree
            $parents = array_values($parents);

            $menu_tree[$key] = $parents;
        }

        $this->menu = $menu_tree;
    }

    protected function findSelected() {

        // do we have a selected menu item already
        foreach ($this->menu as $menu_item) {
            if ($menu_item->getSelected()) {
                return $menu_item;
            }
        }

        // scan looking for a selected item
        foreach ($this->menu as $menu_item) {
            if ($menu_item->getHref()) {
                if (elgg_http_url_is_identical(current_page_url(), $menu_item->getHref())) {
                    $menu_item->setSelected(true);
                    return $menu_item;
                }
            }
        }

        return null;
    }

    protected function sort($sort_by) {

        // sort sections
        ksort($this->menu);

        switch ($sort_by) {
            case 'text':
                $sort_callback = [\ElggMenuBuilder::class, 'compareByText'];
                break;
            case 'name':
                $sort_callback = [\ElggMenuBuilder::class, 'compareByName'];
                break;
            case 'priority':
                $sort_callback = [\ElggMenuBuilder::class, 'compareByPriority'];
                break;
            case 'register':
                // use registration order - usort breaks this
                return;
                break;
            default:
                if (is_callable($sort_by)) {
                    $sort_callback = $sort_by;
                } else {
                    return;
                }
                break;
        }

        // sort each section
        foreach ($this->menu as $index => $section) {
            foreach ($section as $key => $node) {
                $section[$key]->setData('original_order', $key);
            }
            usort($section, $sort_callback);
            $this->menu[$index] = $section;

            // depth first traversal of tree
            foreach ($section as $root) {
                $stack = array();
                array_push($stack, $root);
                while (!empty($stack)) {
                    $node = array_pop($stack);
                    /* @var \ElggMenuItem $node */
                    $node->sortChildren($sort_callback);
                    $children = $node->getChildren();
                    if ($children) {
                        $stack = array_merge($stack, $children);
                    }
                }
            }
        }
    }

    public static function compareByText($a, $b) {
        $at = strip_tags($a->getText());
        $bt = strip_tags($b->getText());

        $result = strnatcmp($at, $bt);
        if ($result === 0) {
            return $a->getData('original_order') - $b->getData('original_order');
        }
        return $result;
    }

    public static function compareByName($a, $b) {
        $an = $a->getName();
        $bn = $b->getName();

        $result = strnatcmp($an, $bn);
        if ($result === 0) {
            return $a->getData('original_order') - $b->getData('original_order');
        }
        return $result;
    }

    public static function compareByPriority($a, $b) {
        $aw = $a->getPriority();
        $bw = $b->getPriority();

        if ($aw == $bw) {
            return $a->getData('original_order') - $b->getData('original_order');
        }
        return $aw - $bw;
    }

    public static function compareByWeight($a, $b) {
        elgg_deprecated_notice("\ElggMenuBuilder::compareByWeight() deprecated by \ElggMenuBuilder::compareByPriority", 1.9);
        $aw = $a->getPriority();
        $bw = $b->getPriority();

        if ($aw == $bw) {
            return $a->getData('original_order') - $b->getData('original_order');
        }
        return $aw - $bw;
    }
}