class AddItemToToolbar

final class AddItemToToolbar implements ConfigActionPluginInterface, ContainerFactoryPluginInterface {
  public function __construct(private readonly ConfigManagerInterface $configManager, private readonly CKEditor5PluginManagerInterface $pluginManager, private readonly string $pluginId) {
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static($container->get(ConfigManagerInterface::class), $container->get(CKEditor5PluginManagerInterface::class), $plugin_id);
  }
  
  /**
   * {@inheritdoc}
   */
  public function apply(string $configName, mixed $value) : void {
    $editor = $this->configManager
      ->loadConfigEntityByName($configName);
    assert($editor instanceof EditorInterface);
    if ($editor->getEditor() !== 'ckeditor5') {
      throw new ConfigActionException(sprintf('The %s config action only works with editors that use CKEditor 5.', $this->pluginId));
    }
    $editor_settings = $editor->getSettings();
    if (is_string($value)) {
      $editor_settings['toolbar']['items'][] = $item_name = $value;
    }
    else {
      assert(is_array($value));
      $item_name = $value['item_name'];
      assert(is_string($item_name));
      $replace = $value['replace'] ?? FALSE;
      assert(is_bool($replace));
      $position = $value['position'] ?? NULL;
      if (is_int($position)) {
        // If we want to replace the item at this position, then `replace`
        // should be true. This would be useful if, for example, we wanted to
        // replace the Image button with the Media Library.
        array_splice($editor_settings['toolbar']['items'], $position, $replace ? 1 : 0, $item_name);
      }
      else {
        $editor_settings['toolbar']['items'][] = $item_name;
      }
    }
    // If we're just adding a vertical separator, there's nothing else we need
    // to do at this point.
    if ($item_name === '|') {
      return;
    }
    // If this item is associated with a plugin, ensure that it's configured
    // at the editor level, if necessary.
    /** @var \Drupal\ckeditor5\Plugin\CKEditor5PluginDefinition $definition */
    foreach ($this->pluginManager
      ->getDefinitions() as $id => $definition) {
      if (array_key_exists($item_name, $definition->getToolbarItems())) {
        // If plugin settings already exist, don't change them.
        if (array_key_exists($id, $editor_settings['plugins'])) {
          break;

        }
        elseif ($definition->isConfigurable()) {
          /** @var \Drupal\ckeditor5\Plugin\CKEditor5PluginConfigurableInterface $plugin */
          $plugin = $this->pluginManager
            ->getPlugin($id, NULL);
          $editor_settings['plugins'][$id] = $plugin->defaultConfiguration();
        }
        // No need to examine any other plugins.
        break;

      }
    }
    $editor->setSettings($editor_settings)
      ->save();
  }

}