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 {
    // Normalize $value, which could be one of three things:
    // - A string (add one item to the toolbar, no additional options)
    // - An associative array (add one item to the toolbar, with options)
    // - An indexed array (add multiple items to the toolbar, each of which
    //   could be one of the previous two forms)
    if (is_string($value) || is_array($value) && !array_is_list($value)) {
      $value = [
        $value,
      ];
    }
    if (!is_array($value) || $value === []) {
      throw new ConfigActionException(sprintf('The %s config action requires one or more toolbar items.', $this->pluginId));
    }
    $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));
    }
    $changed = FALSE;
    foreach ($value as $item) {
      if (!is_string($item) && !is_array($item)) {
        throw new ConfigActionException(sprintf('The %s config action requires each toolbar item to be a string or an array of options.', $this->pluginId));
      }
      $changed = $this->applySingle($editor, $item) || $changed;
    }
    if ($changed) {
      $editor->save();
    }
  }
  
  /**
   * Adds an item to the toolbar.
   *
   * @param \Drupal\editor\EditorInterface $editor
   *   The editor to which the item should be added.
   * @param string|array $value
   *   The name of the item, or an array of options for the item.
   *
   * @return bool
   *   TRUE if the editor settings were changed, FALSE otherwise.
   */
  private function applySingle(EditorInterface $editor, string|array $value) : bool {
    if (is_string($value)) {
      $value = [
        'item_name' => $value,
      ];
    }
    $item_name = $value['item_name'] ?? NULL;
    if (!is_string($item_name)) {
      throw new ConfigActionException(sprintf("The %s config action requires each toolbar item to define an 'item_name' string.", $this->pluginId));
    }
    $replace = $value['replace'] ?? FALSE;
    assert(is_bool($replace));
    $position = $value['position'] ?? NULL;
    $allow_duplicate = $value['allow_duplicate'] ?? FALSE;
    assert(is_bool($allow_duplicate));
    $editor_settings = $editor->getSettings();
    // If the item is already in the toolbar and we're not allowing duplicate
    // items, we're done.
    if (in_array($item_name, $editor_settings['toolbar']['items'], TRUE) && $allow_duplicate === FALSE && $item_name !== '|') {
      return FALSE;
    }
    if (is_int($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'][] = $item_name;
    }
    // If this item is associated with a plugin, ensure that it's configured
    // at the editor level, if necessary. A vertical separator is not
    // associated with any plugin.
    if ($item_name !== '|') {
      /** @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);
    return TRUE;
  }

}