class TelephoneHooks

class TelephoneHooks {
    
    /**
     * Implements hook_help().
     */
    public function help($route_name, RouteMatchInterface $route_match) {
        switch ($route_name) {
            case 'help.page.telephone':
                $output = '';
                $output .= '<h2>' . t('About') . '</h2>';
                $output .= '<p>' . t('The Telephone module allows you to create fields that contain telephone numbers. See the <a href=":field">Field module help</a> and the <a href=":field_ui">Field UI help</a> pages for general information on fields and how to create and manage them. For more information, see the <a href=":telephone_documentation">online documentation for the Telephone module</a>.', [
                    ':field' => Url::fromRoute('help.page', [
                        'name' => 'field',
                    ])->toString(),
                    ':field_ui' => \Drupal::moduleHandler()->moduleExists('field_ui') ? Url::fromRoute('help.page', [
                        'name' => 'field_ui',
                    ])->toString() : '#',
                    ':telephone_documentation' => 'https://www.drupal.org/documentation/modules/telephone',
                ]) . '</p>';
                $output .= '<h2>' . t('Uses') . '</h2>';
                $output .= '<dl>';
                $output .= '<dt>' . t('Managing and displaying telephone fields') . '</dt>';
                $output .= '<dd>' . t('The <em>settings</em> and the <em>display</em> of the telephone field can be configured separately. See the <a href=":field_ui">Field UI help</a> for more information on how to manage fields and their display.', [
                    ':field_ui' => \Drupal::moduleHandler()->moduleExists('field_ui') ? Url::fromRoute('help.page', [
                        'name' => 'field_ui',
                    ])->toString() : '#',
                ]) . '</dd>';
                $output .= '<dt>' . t('Displaying telephone numbers as links') . '</dt>';
                $output .= '<dd>' . t('Telephone numbers can be displayed as links with the scheme name <em>tel:</em> by choosing the <em>Telephone</em> display format on the <em>Manage display</em> page. Any spaces will be stripped out of the link text. This semantic markup improves the user experience on mobile and assistive technology devices.') . '</dd>';
                $output .= '</dl>';
                return $output;
        }
    }
    
    /**
     * Implements hook_field_formatter_info_alter().
     */
    public function fieldFormatterInfoAlter(&$info) {
        $info['string']['field_types'][] = 'telephone';
    }
    
    /**
     * Implements hook_field_type_category_info_alter().
     */
    public function fieldTypeCategoryInfoAlter(&$definitions) {
        // The `telephone` field type belongs in the `general` category, so the
        // libraries need to be attached using an alter hook.
        $definitions[FieldTypeCategoryManagerInterface::FALLBACK_CATEGORY]['libraries'][] = 'telephone/drupal.telephone-icon';
    }

}