class BlockSettings

class BlockSettings extends ProcessPluginBase implements ContainerFactoryPluginInterface {
  
  /**
   * The block manager service.
   *
   * @var \Drupal\Core\Block\BlockManagerInterface
   */
  protected readonly BlockManagerInterface $blockManager;
  public function __construct(array $configuration, $plugin_id, $plugin_definition, ?BlockManagerInterface $blockManager = NULL) {
    if (empty($blockManager)) {
      @trigger_error('Calling ' . __METHOD__ . '() without the $blockManager parameter is deprecated in drupal:11.2.0 and must be provided in drupal:12.0.0. See https://www.drupal.org/node/3522023', E_USER_DEPRECATED);
      $blockManager = \Drupal::service(BlockManagerInterface::class);
    }
    $this->blockManager = $blockManager;
    parent::__construct($configuration, $plugin_id, $plugin_definition);
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) : static {
    return new static($configuration, $plugin_id, $plugin_definition, $container->get(BlockManagerInterface::class));
  }
  
  /**
   * {@inheritdoc}
   *
   * Set the block configuration.
   */
  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
    [$plugin, $delta, $old_settings, $title] = $value;
    $settings = [];
    $settings['label'] = $title;
    if ($title && $title !== '<none>') {
      $settings['label_display'] = BlockPluginInterface::BLOCK_LABEL_VISIBLE;
    }
    else {
      $settings['label_display'] = '0';
    }
    switch ($plugin) {
      case 'aggregator_feed_block':
        [, $id] = explode('-', $delta);
        $settings['block_count'] = $old_settings['aggregator']['item_count'];
        $settings['feed'] = $id;
        break;

      case 'book_navigation':
        $settings['block_mode'] = $old_settings['book']['block_mode'];
        break;

      case 'forum_active_block':
      case 'forum_new_block':
        $settings['block_count'] = $old_settings['forum']['block_num'];
        break;

      case 'statistics_popular_block':
        $settings['top_day_num'] = $old_settings['statistics']['statistics_block_top_day_num'];
        $settings['top_all_num'] = $old_settings['statistics']['statistics_block_top_all_num'];
        $settings['top_last_num'] = $old_settings['statistics']['statistics_block_top_last_num'];
        break;

      case 'views_block:who_s_new-block_1':
        $settings['items_per_page'] = $old_settings['user']['block_whois_new_count'];
        break;

      case 'views_block:who_s_online-who_s_online_block':
        $settings['items_per_page'] = $old_settings['user']['max_list_count'];
        break;

    }
    // Let the block plugin fill in any missing settings.
    $settings = $this->blockManager
      ->createInstance($plugin, $settings)
      ->getConfiguration();
    return $settings;
  }

}