ElggMenuBuilder.php

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<?php

use Elgg\Exceptions\InvalidArgumentException as ElggInvalidArgumentException;
use Elgg\Menu\MenuItems;
use Elgg\Menu\PreparedMenu;

class ElggMenuBuilder {

    protected $items;

    protected $selected_item = null;

    public function __construct($items) {
        if (is_array($items)) {
            $items = new MenuItems($items);
        }

        if (!$items instanceof MenuItems) {
            throw new ElggInvalidArgumentException(__CLASS__ . ' expects an instanceof of ' . MenuItems::class);
        }

        $this->items = $items;
    }

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

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

        return $this->prepare($this->filterByContext(), $sort_by);
    }

    public function setSelected(string $item_name) {
        $menu_item = $this->items->get($item_name);
        if (!$menu_item instanceof ElggMenuItem) {
            return false;
        }
        
        $menu_item->setSelected();
        
        return true;
    }
    
    public function getSelected() {
        return $this->selected_item;
    }

    protected function filterByContext() {
        return $this->items->filter(function (ElggMenuItem $item) {
            return $item->inContext();
        });
    }

    protected function prepare(MenuItems $items, $sort_by = 'priority') {
        $menu = $this->setupSections($items);
        $menu = $this->setupTrees($menu);
        
        return $this->sort($menu, $sort_by);
    }

    protected function setupSections(MenuItems $items) {
        $menu = new PreparedMenu();

        $section_ids = $items->map(function (ElggMenuItem $item) {
            return $item->getSection();
        });

        $section_ids = array_unique(array_values($section_ids));

        foreach ($section_ids as $index => $section_id) {
            $section_items = $items->filter(function (ElggMenuItem $item) use ($section_id) {
                return $item->getSection() == $section_id;
            });

            $section = new \Elgg\Menu\MenuSection();

            $section->setId($section_id);
            $section->setPriority($index);
            $section->fill($section_items);

            $menu->add($section);
        }

        return $menu;
    }

    protected function setupTrees(PreparedMenu $menu) {

        return $menu->walk(function (\Elgg\Menu\MenuSection $section) {

            $parents = [];
            $children = [];
            $all_menu_items = [];

            // 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
                return;
            }

            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
                return;
            }

            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', [
                        $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
                    $message = _elgg_services()->translator->translate('ElggMenuBuilder:Trees:DuplicateChild', [$menu_item_name]);
                    _elgg_services()->logger->notice($message);
                }
            }
            
            // convert keys to indexes for first level of tree
            $parents = array_values($parents);

            $section->fill($parents);
        });
    }

    protected function findSelected() {
        foreach ($this->items as $menu_item) {
            if ($menu_item->getSelected()) {
                return $menu_item;
            }
        }
    }

    protected function sort(PreparedMenu $menu, $sort_by) {

        $menu->sort(function (\Elgg\Menu\MenuSection $s1, \Elgg\Menu\MenuSection $s2) {
            return strnatcmp($s1->getID(), $s2->getID());
        });

        $sorter = $this->getSortCallback($sort_by);

        if (!$sorter) {
            return $menu;
        }

        return $menu->walk(function (\Elgg\Menu\MenuSection $section) use ($sorter) {
            $indices = array_keys($section->all());

            $section->walk(function (\ElggMenuItem $item) use ($indices, $sorter) {
                $item->setData('original_order', array_search($item->getID(), $indices));
                $item->sortChildren($sorter);
            });

            $section->sort($sorter);
        });
    }

    protected function getSortCallback($sort_by = null) {
        switch ($sort_by) {
            case 'text':
                return [self::class, 'compareByText'];

            case 'name':
                return [self::class, 'compareByName'];

            case 'priority':
                return [self::class, 'compareByPriority'];
        }

        return $sort_by && is_callable($sort_by) ? $sort_by : null;
    }

    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;
    }
}