class ThemePreprocess

class ThemePreprocess {
    use StringTranslationTrait;
    public function __construct(ConfigFactoryInterface $configFactory, PathMatcherInterface $pathMatcher, CurrentPathStack $currentPathStack, LanguageManagerInterface $languageManager, RendererInterface $renderer, RouteMatchInterface $routeMatch, ThemeManagerInterface $themeManager) {
    }
    
    /**
     * Prepares variables for container templates.
     *
     * Default template: container.html.twig.
     *
     * @param array $variables
     *   An associative array containing:
     *   - element: An associative array containing the properties of the element.
     *     Properties used: #id, #attributes, #children.
     */
    public function preprocessContainer(array &$variables) : void {
        $variables['has_parent'] = FALSE;
        $element = $variables['element'];
        // Ensure #attributes is set.
        $element += [
            '#attributes' => [],
        ];
        // Special handling for form elements.
        if (isset($element['#array_parents'])) {
            // Assign an html ID.
            if (!isset($element['#attributes']['id'])) {
                $element['#attributes']['id'] = $element['#id'];
            }
            $variables['has_parent'] = TRUE;
        }
        $variables['children'] = $element['#children'];
        $variables['attributes'] = $element['#attributes'];
    }
    
    /**
     * Prepares variables for links templates.
     *
     * Default template: links.html.twig.
     *
     * Unfortunately links templates duplicate the "active" class handling of l()
     * and LinkGenerator::generate() because it needs to be able to set the
     * "active" class not on the links themselves (<a> tags), but on the list
     * items (<li> tags) that contain the links. This is necessary for CSS to be
     * able to style list items differently when the link is active, since CSS
     * does not yet allow one to style list items only if it contains a certain
     * element with a certain class. I.e. we cannot yet convert this jQuery
     * selector to a CSS selector: jQuery('li:has("a.is-active")')
     *
     * @param array $variables
     *   An associative array containing:
     *   - links: An array of links to be themed. Each link itself is an array,
     *     with the following elements:
     *     - title: The link text.
     *     - url: (optional) The \Drupal\Core\Url object to link to. If the 'url'
     *       element is supplied, the 'title' and 'url' are used to generate a
     *       link through \Drupal::linkGenerator()->generate(). All data from the
     *       link array other than 'title' and 'url' are added as #options on
     *       the URL object. See \Drupal\Core\Url::fromUri() for details on the
     *       options. If no 'url' is supplied, the 'title' is printed as plain
     *       text.
     *     - attributes: (optional) Attributes for the anchor, or for the <span>
     *       tag used in its place if no 'url' is supplied. If element 'class' is
     *       included, it must be an array of one or more class names.
     *   - attributes: A keyed array of attributes for the <ul> containing the
     *     list of links.
     *   - set_active_class: (optional) Whether each link should compare the
     *     route_name + route_parameters or URL (path), language, and query
     *     options to the current URL, to determine whether the link is "active".
     *     If so, attributes will be added to the HTML elements for both the link
     *     and the list item that contains it, which will result in an "is-active"
     *     class being added to both. The class is added via JavaScript for
     *     authenticated users (in the active-link library), and via PHP for
     *     anonymous users (in the
     *     \Drupal\Core\EventSubscriber\ActiveLinkResponseFilter class).
     *   - heading: (optional) A heading to precede the links. May be an
     *     associative array or a string. If it's an array, it can have the
     *     following elements:
     *     - text: The heading text.
     *     - level: The heading level (e.g. 'h2', 'h3').
     *     - attributes: (optional) An array of the CSS attributes for the
     *       heading.
     *     When using a string it will be used as the text of the heading and the
     *     level will default to 'h2'. Headings should be used on navigation menus
     *     and any list of links that consistently appears on multiple pages. To
     *     make the heading invisible use the 'visually-hidden' CSS class. Do not
     *     use 'display:none', which removes it from screen readers and assistive
     *     technology. Headings allow screen reader and keyboard only users to
     *     navigate to or skip the links. See
     *     http://juicystudio.com/article/screen-readers-display-none.php and
     *     https://www.w3.org/TR/WCAG-TECHS/H42.html for more information.
     *
     * @see \Drupal\Core\Utility\LinkGenerator
     * @see \Drupal\Core\Utility\LinkGenerator::generate()
     * @see system_page_attachments()
     */
    public function preprocessLinks(array &$variables) : void {
        $links = $variables['links'];
        $heading =& $variables['heading'];
        if (!empty($links)) {
            // Prepend the heading to the list, if any.
            if (!empty($heading)) {
                // Convert a string heading into an array, using a <h2> tag by default.
                if (is_string($heading)) {
                    $heading = [
                        'text' => $heading,
                    ];
                }
                // Merge in default array properties into $heading.
                $heading += [
                    'level' => 'h2',
                    'attributes' => [],
                ];
                // Convert the attributes array into an Attribute object.
                $heading['attributes'] = new Attribute($heading['attributes']);
            }
            $variables['links'] = [];
            foreach ($links as $key => $link) {
                $item = [];
                $link += [
                    'ajax' => NULL,
                    'url' => NULL,
                ];
                $li_attributes = [];
                $keys = [
                    'title',
                    'url',
                ];
                $link_element = [
                    '#type' => 'link',
                    '#title' => $link['title'],
                    '#options' => array_diff_key($link, array_combine($keys, $keys)),
                    '#url' => $link['url'],
                    '#ajax' => $link['ajax'],
                ];
                // Handle links and ensure that the active class is added on the LIs,
                // but only if the 'set_active_class' option is not empty. Links
                // templates duplicate the "is-active" class handling of l() and
                // LinkGenerator::generate() because they need to be able to set the
                // "is-active" class not on the links themselves (<a> tags), but on the
                // list items (<li> tags) that contain the links. This is necessary for
                // CSS to be able to style list items differently when the link is
                // active, since CSS does not yet allow one to style list items only if
                // they contain a certain element with a certain class. That is, we
                // cannot yet convert this jQuery selector to a CSS selector:
                // jQuery('li:has("a.is-active")')
                if (isset($link['url'])) {
                    if (!empty($variables['set_active_class'])) {
                        // Also enable set_active_class for the contained link.
                        $link_element['#options']['set_active_class'] = TRUE;
                        if (!empty($link['language'])) {
                            $li_attributes['hreflang'] = $link['language']->getId();
                        }
                        // Add a "data-drupal-link-query" attribute to let the
                        // drupal.active-link library know the query in a standardized
                        // manner. Only add the data- attribute. The "is-active" class will
                        // be calculated using JavaScript, to prevent breaking the render
                        // cache.
                        if (!empty($link['query'])) {
                            $query = $link['query'];
                            ksort($query);
                            $li_attributes['data-drupal-link-query'] = Json::encode($query);
                        }
                        
                        /** @var \Drupal\Core\Url $url */
                        $url = $link['url'];
                        if ($url->isRouted()) {
                            // Add a "data-drupal-link-system-path" attribute to let the
                            // drupal.active-link library know the path in a standardized
                            // manner. Only add the data- attribute. The "is-active" class
                            // will be calculated using JavaScript, to prevent breaking the
                            // render cache.
                            $system_path = $url->getInternalPath();
                            // @todo System path is deprecated - use the route name and parameters.
                            // Special case for the front page.
                            $li_attributes['data-drupal-link-system-path'] = $system_path == '' ? '<front>' : $system_path;
                        }
                    }
                    $item['link'] = $link_element;
                }
                // Handle title-only text items.
                $item['text'] = $link['title'];
                if (isset($link['attributes'])) {
                    $item['text_attributes'] = new Attribute($link['attributes']);
                }
                // Handle list item attributes.
                $item['attributes'] = new Attribute($li_attributes);
                // Add the item to the list of links.
                $variables['links'][$key] = $item;
            }
        }
    }
    
    /**
     * Prepares variables for HTML document templates.
     *
     * Default template: html.html.twig.
     *
     * @param array $variables
     *   An associative array containing:
     *   - page: A render element representing the page.
     */
    public function preprocessHtml(array &$variables) : void {
        $variables['page'] = $variables['html']['page'];
        unset($variables['html']['page']);
        $variables['page_top'] = NULL;
        if (isset($variables['html']['page_top'])) {
            $variables['page_top'] = $variables['html']['page_top'];
            unset($variables['html']['page_top']);
        }
        $variables['page_bottom'] = NULL;
        if (isset($variables['html']['page_bottom'])) {
            $variables['page_bottom'] = $variables['html']['page_bottom'];
            unset($variables['html']['page_bottom']);
        }
        $variables['html_attributes'] = new Attribute();
        // <html> element attributes.
        $language_interface = $this->languageManager
            ->getCurrentLanguage();
        $variables['html_attributes']['lang'] = $language_interface->getId();
        $variables['html_attributes']['dir'] = $language_interface->getDirection();
        if (isset($variables['db_is_active']) && !$variables['db_is_active']) {
            $variables['db_offline'] = TRUE;
        }
        // Add a variable for the root path. This can be used to create a class and
        // theme the page depending on the current path (e.g. node, admin, user) as
        // well as more specific data like path-frontpage.
        $is_front_page = $this->pathMatcher
            ->isFrontPage();
        if ($is_front_page) {
            $variables['root_path'] = FALSE;
        }
        else {
            $system_path = $this->currentPathStack
                ->getPath();
            $variables['root_path'] = explode('/', $system_path)[1];
        }
        $site_config = $this->configFactory
            ->get('system.site');
        // Construct page title.
        if (isset($variables['page']['#title']) && is_array($variables['page']['#title'])) {
            // Do an early render if the title is a render array.
            $variables['page']['#title'] = (string) $this->renderer
                ->render($variables['page']['#title']);
        }
        if (!empty($variables['page']['#title'])) {
            $head_title = [
                // Marking the title as safe since it has had the tags stripped.
'title' => Markup::create(trim(strip_tags($variables['page']['#title']))),
                'name' => $site_config->get('name'),
            ];
        }
        elseif ($is_front_page) {
            $head_title = [
                'title' => $this->t('Home'),
                'name' => $site_config->get('name'),
            ];
        }
        else {
            $head_title = [
                'name' => $site_config->get('name'),
            ];
            if ($site_config->get('slogan')) {
                $head_title['slogan'] = strip_tags($site_config->get('slogan'));
            }
        }
        $variables['head_title'] = $head_title;
        // Create placeholder strings for these keys.
        // @see \Drupal\Core\Render\HtmlResponseSubscriber
        $types = [
            'styles' => 'css',
            'scripts' => 'js',
            'scripts_bottom' => 'js-bottom',
            'head' => 'head',
        ];
        $variables['placeholder_token'] = Crypt::randomBytesBase64(55);
        foreach ($types as $type => $placeholder_name) {
            $placeholder = '<' . $placeholder_name . '-placeholder token="' . $variables['placeholder_token'] . '">';
            $variables['#attached']['html_response_attachment_placeholders'][$type] = $placeholder;
        }
    }
    
    /**
     * Prepares variables for the page template.
     *
     * Default template: page.html.twig.
     *
     * See the page.html.twig template for the list of variables.
     */
    public function preprocessPage(array &$variables) : void {
        $language_interface = $this->languageManager
            ->getCurrentLanguage();
        foreach ($this->themeManager
            ->getActiveTheme()
            ->getRegions() as $region) {
            if (!isset($variables['page'][$region])) {
                $variables['page'][$region] = [];
            }
        }
        $variables['base_path'] = base_path();
        $variables['front_page'] = Url::fromRoute('<front>')->toString();
        $variables['language'] = $language_interface;
        // An exception might be thrown.
        try {
            $variables['is_front'] = $this->pathMatcher
                ->isFrontPage();
        } catch (\Exception) {
            // If the database is not yet available, set default values for these
            // variables.
            $variables['is_front'] = FALSE;
            $variables['db_is_active'] = FALSE;
        }
        if (($node = $this->routeMatch
            ->getParameter('node')) || ($node = $this->routeMatch
            ->getParameter('node_preview'))) {
            $variables['node'] = $node;
        }
    }

}