class NavigationContentLinks

final class NavigationContentLinks implements ContainerInjectionInterface {
    use StringTranslationTrait;
    
    /**
     * Construct a new NavigationContentLinks object.
     *
     * @param \Drupal\Core\Routing\RouteProviderInterface $routeProvider
     *   The route provider.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entityTypeManager
     *   The entity type manager.
     */
    public function __construct(RouteProviderInterface $routeProvider, EntityTypeManagerInterface $entityTypeManager) {
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('router.route_provider'), $container->get('entity_type.manager'));
    }
    
    /**
     * Add links to the Content menu, based on enabled modules.
     *
     * @param array $links
     *   The array of links being altered.
     */
    public function addMenuLinks(array &$links) : void {
        // First, add the top-level menu items.
        // @todo Consider turning this into a data object so we can avoid typos in
        // array keys.
        $content_links = [
            'navigation.create' => [
                'route_name' => 'node.add_page',
                'title' => $this->t('Create'),
                'weight' => -10,
            ],
            'navigation.content' => [
                'route_name' => 'view.content.page_1',
                'title' => $this->t('Content'),
            ],
            'navigation.files' => [
                'route_name' => 'view.files.page_1',
                'title' => $this->t('Files'),
            ],
            'navigation.media' => [
                'route_name' => 'view.media.media_page_list',
                'title' => $this->t('Media'),
            ],
            'navigation.blocks' => [
                'route_name' => 'view.block_content.page_1',
                'title' => $this->t('Blocks'),
            ],
        ];
        foreach ($content_links as $link_name => $link) {
            $this->addLink($link_name, $link, $links);
        }
        // Add supported add links under the Create button.
        $this->addCreateEntityLinks('node_type', 'node.add', $links);
        $this->addCreateEntityLinks('media_type', 'entity.media.add_form', $links, [
            'document',
            'image',
        ]);
        // Finally, add the bundleless User link and pin it to the bottom.
        $this->addLink('navigation.create.user', [
            'route_name' => 'user.admin_create',
            'title' => $this->t('User'),
            'parent' => 'navigation.create',
            'weight' => 100,
        ], $links);
    }
    
    /**
     * Remove the admin/content link, and any direct children.
     *
     * @param array $links
     *   The array of links being altered.
     */
    public function removeAdminContentLink(array &$links) : void {
        unset($links['system.admin_content']);
        // Also remove any links that have set admin/content as their parent link.
        // They are unsupported by the Navigation module.
        foreach ($links as $link_name => $link) {
            if (isset($link['parent']) && $link['parent'] === 'system.admin_content') {
                // @todo Do we need to make this recursive, and unset children of these
                // links too?
                unset($links[$link_name]);
            }
        }
    }
    
    /**
     * Remove the help link as render it outside any menu.
     *
     * @param array $links
     *   The array of links being altered.
     */
    public function removeHelpLink(array &$links) : void {
        unset($links['help.main']);
    }
    
    /**
     * Add create links for an entity type.
     *
     * This function preserves the order of entity types as it is called.
     *
     * @param string $entity_type
     *   The entity type to add links for, such as node_type.
     * @param string $add_route_id
     *   The ID of the route for the entity type add form.
     * @param array $links
     *   The existing array of links to add to.
     * @param array $bundle_allow_list
     *   A list of allowed bundles to include. Can be used to limit the list of
     *   bundles that are included for noisy entity types like media.
     */
    private function addCreateEntityLinks(string $entity_type, string $add_route_id, array &$links, array $bundle_allow_list = []) : void {
        // Ensure subsequent calls always get added to the bottom, and not in
        // alphabetical order.
        static $weight = 0;
        // The module providing the entity type is either not installed, or in the
        // process of being uninstalled.
        if (!$this->entityTypeManager
            ->hasDefinition($entity_type)) {
            return;
        }
        // Sort all types within an entity type alphabetically.
        $definition = $this->entityTypeManager
            ->getDefinition($entity_type);
        $types = $this->entityTypeManager
            ->getStorage($entity_type)
            ->loadMultiple();
        if (method_exists($definition->getClass(), 'sort')) {
            uasort($types, [
                $definition->getClass(),
                'sort',
            ]);
        }
        $add_content_links = [];
        foreach ($types as $type) {
            // Skip if the bundle is not in the allow list.
            if (!empty($bundle_allow_list) && !in_array($type->id(), $bundle_allow_list)) {
                continue;
            }
            $add_content_links['navigation.content.' . $type->getEntityTypeId() . '.' . $type->id()] = [
                'title' => $type->label(),
                'route_name' => $add_route_id,
                'route_parameters' => [
                    $entity_type => $type->id(),
                ],
                'parent' => 'navigation.create',
                'weight' => $weight,
            ];
        }
        foreach ($add_content_links as $link_name => $link) {
            $this->addLink($link_name, $link, $links);
        }
        $weight++;
    }
    
    /**
     * Ensure a route exists and add the link.
     *
     * @param string $link_name
     *   The name of the link being added.
     * @param array $link
     *   The link array, as defined in hook_menu_links_discovered_alter().
     * @param array $links
     *   The existing array of links.
     */
    private function addLink(string $link_name, array $link, array &$links) : void {
        try {
            // Ensure the route exists (there is no separate "exists" method).
            $this->routeProvider
                ->getRouteByName($link['route_name']);
            $links[$link_name] = $link + [
                'menu_name' => 'content',
                'provider' => 'navigation',
            ];
        } catch (RouteNotFoundException $e) {
            // The module isn't installed, or the route (such as provided by a view)
            // has been deleted.
        }
    }

}