Issue #3245967 by bnjmnm, Wim Leers, nod_, lauriii, tim.plunkett, andregp,...

      $output .= '<dl>';

      $output .= '<dt>' . t('Enabling CKEditor 5 for individual text formats') . '</dt>';

      $output .= '<dd>' . t('CKEditor 5 has to be enabled and configured separately for individual text formats from the <a href=":formats">Text formats and editors page</a> because the filter settings for each text format can be different. For more information, see the <a href=":text_editor">Text Editor help page</a> and <a href=":filter">Filter help page</a>.', [':formats' => Url::fromRoute('filter.admin_overview')->toString(), ':text_editor' => Url::fromRoute('help.page', ['name' => 'editor'])->toString(), ':filter' => Url::fromRoute('help.page', ['name' => 'filter'])->toString()]) . '</dd>';

      $output .= '<dt>' . t('Migration for existing text formats switching to CKEditor 5') . '</dt>';

      $output .= '<dd>' . t('Text formats switching to CKEditor 5 from CKEditor 4 (or no text editor) should be able to do so with minimal effort and zero data loss. Existing configuration will be automatically migrated to CKEditor 5 compatible configuration. In instances where functionality can not be migrated, detailed messages are provided explaining what is necessary for feature parity.') . '</dd>';

      $output .= '<dt>' . t('Configuring the toolbar') . '</dt>';

      $output .= '<dd>' . t('When CKEditor 5 is chosen from the <em>Text editor</em> drop-down menu, its toolbar configuration is displayed. You can add and remove buttons from the <em>Active toolbar</em> by dragging and dropping them. Separators and rows can be added to organize the buttons.') . '</dd>';

      $output .= '<dt>' . t('Filtering HTML content') . '</dt>';

      $output .= '</ul>';

      $output .= '</dd>';

      $output .= '</dl>';

      $output .= '<h3 id="migration-settings">' . t('Migrating an Existing Text Format to CKEditor 5') . '</h3>';

      $output .= '<p>' . t('When switching an existing text format to use CKEditor 5, an automatic process is initiated that helps text formats switching to CKEditor 5 from CKEditor 4 (or no text editor) to do so with minimal effort and zero data loss.') . '</p>';

      $output .= '<p>' . t("This process is designed for there to be no data loss risk in switching to CKEditor 5. However some of your editor's functionality may not be 100% equivalent to what was available previously. In most cases, these changes are minimal. After the process completes, status and/or warning messages will summarize any changes that occurred, and more detailed information will be available in the site's logs.") . '</p>';

      $output .= '<p>' . t('CKEditor 5 will attempt to enable plugins that provide equivalent toolbar items to those used prior to switching to CKEditor 5. All core CKEditor 4 plugins and many popular contrib plugins already have CKEditor 5 equivalents. In some cases, functionality that required contrib modules is now built into CKEditor 5. In instances where a plugin does not have an equivalent, no data loss will occur but elements previously provided via the plugin may need to be added manually as HTML via source editing.') . '</p>';

      $output .= '<h4>' . t('Additional migration considerations for text formats with restricted HTML') . '</h4>';

      $output .= '<dl>';

      $output .= '<dt>' . t('The “Allowed HTML tags" field in the “Limit allowed HTML tags and correct Faulty HTML" filter is now read-only') . '</dt>';

      $output .= '<dd>' . t('This field accurately represents the tags/attributes allowed by a text format, but the allowed tags are based on which plugins are enabled and how they are configured. For example, enabling the Underline plugin adds the &lt;u&gt; tag to “Allowed HTML tags".') . '</dd>';

      $output .= '<dt id="required-tags">' . t('The &lt;p&gt; and &lt;br &gt; tags will be automatically added to your text format.') . '</dt>';

      $output .= '<dd>' . t('CKEditor 5 requires the &lt;p&gt; and &lt;br &gt; tags to achieve basic functionality. They will be automatically added to “Allowed HTML tags" on formats that previously did not allow them.') . '</dd>';

      $output .= '<dt id="source-editing">' . t('Tags/attributes that are not explicitly supported by any plugin are supported by Source Editing') . '</dt>';

      $output .= '<dd>' . t('When a necessary tag/attribute is not directly supported by an available plugin, the "Source Editing" plugin is enabled. This plugin is typically used for by passing the CKEditor 5 UI and editing contents as HTML source. In the settings for Source Editing, tags/attributes that aren\'t available via other plugins are added to Source Editing\'s "Manually editable HTML tags" setting so they are supported by the text format.') . '</dd>';

      $output .= '</dl>';

      return $output;

  }

}

    arguments:

      - '@plugin.manager.ckeditor5.plugin'

      - '@plugin.manager.ckeditor4to5upgrade.plugin'

      - '@logger.channel.ckeditor5'

      - '@module_handler'

      - '@current_user'

      - '@?plugin.manager.ckeditor.plugin'

  ckeditor5.stylesheets.message:

    class: Drupal\ckeditor5\CKEditor5StylesheetsMessage

    arguments:

    arguments: ['@cache_tags.invalidator']

    tags:

      - { name: event_subscriber }

  logger.channel.ckeditor5:

    parent: logger.channel_base

    arguments: [ 'ckeditor5' ]

use Drupal\editor\Entity\Editor;

use Drupal\editor\Plugin\EditorBase;

use Drupal\filter\FilterFormatInterface;

use Psr\Log\LoggerInterface;

use Symfony\Component\DependencyInjection\ContainerInterface;

use Symfony\Component\Validator\ConstraintViolation;

use Symfony\Component\Validator\ConstraintViolationListInterface;

   */

  private $stylesheetsMessage;

  /**

   * A logger instance.

   *

   * @var \Psr\Log\LoggerInterface

   */

  protected $logger;

  /**

   * Constructs a CKEditor5 editor plugin.

   *

   *   The cache.

   * @param \Drupal\ckeditor5\CKEditor5StylesheetsMessage $stylesheets_message

   *   The ckeditor_stylesheets message utility.

   * @param \Psr\Log\LoggerInterface $logger

   *   A logger instance.

   */

  public function __construct(array $configuration, $plugin_id, $plugin_definition, CKEditor5PluginManagerInterface $ckeditor5_plugin_manager, LanguageManagerInterface $language_manager, ModuleHandlerInterface $module_handler, SmartDefaultSettings $smart_default_settings, CacheBackendInterface $cache, CKEditor5StylesheetsMessage $stylesheets_message) {

  public function __construct(array $configuration, $plugin_id, $plugin_definition, CKEditor5PluginManagerInterface $ckeditor5_plugin_manager, LanguageManagerInterface $language_manager, ModuleHandlerInterface $module_handler, SmartDefaultSettings $smart_default_settings, CacheBackendInterface $cache, CKEditor5StylesheetsMessage $stylesheets_message, LoggerInterface $logger) {

    parent::__construct($configuration, $plugin_id, $plugin_definition);

    $this->ckeditor5PluginManager = $ckeditor5_plugin_manager;

    $this->languageManager = $language_manager;

    $this->smartDefaultSettings = $smart_default_settings;

    $this->cache = $cache;

    $this->stylesheetsMessage = $stylesheets_message;

    $this->logger = $logger;

  }

  /**

      $container->get('module_handler'),

      $container->get('ckeditor5.smart_default_settings'),

      $container->get('cache.default'),

      $container->get('ckeditor5.stylesheets.message')

      $container->get('ckeditor5.stylesheets.message'),

      $container->get('logger.channel.ckeditor5')

    );

  }

      assert($editor->getSettings() === $this->getDefaultSettings());

      if (!$format->isNew()) {

        [$editor, $messages] = $this->smartDefaultSettings->computeSmartDefaultSettings($editor, $format);

        $form_state->set('used_smart_default_settings', TRUE);

        foreach ($messages as $type => $messages_per_type) {

          foreach ($messages_per_type as $message) {

            $this->messenger()->addMessage($message, $type);

    $form_state->setValues($editor->getSettings());

    parent::submitConfigurationForm($form, $form_state);

    if ($form_state->get('used_smart_default_settings')) {

      $format_name = $editor->getFilterFormat()->get('name');

      $this->logger->info($this->t('The migration of %text_format to CKEditor 5 has been saved.', ['%text_format' => $format_name]));

    }

  }

  /**

    $page->selectFieldOption('editor[editor]', 'ckeditor5');

    $assert_session->assertWaitOnAjaxRequest();

    $assert_session->pageTextContains('The following tag(s) were added to Limit allowed HTML tags and correct faulty HTML, because they are needed to provide fundamental CKEditor 5 functionality : <br> <p>');

    $assert_session->pageTextContains('The <br>, <p> tags were added because they are required by CKEditor 5');

    $this->assertHtmlEsqueFieldValueEquals('filters[filter_html][settings][allowed_html]', $this->defaultElementsAfterUpdatingToCkeditor5);

    $page->pressButton('Save configuration');