protected function prepareItem($item)
    {
        if (!isset($item["type"])) {
            return $item;
        }

        if (isset($item["children"])) {
            $item["children"] = $this->prepareItems($item["children"]);
        }

        switch ($item['type']) {
            case 'select':
                if (isset($item['sql'])) {
                    $connectionName = isset($item['connection']) ? $item['connection'] : 'default';
                    $sql            = $item['sql'];
                    $options        = isset($item["options"]) ? $item["options"] : array();

                    unset($item['sql']);
                    unset($item['connection']);
                    /** @var Connection $connection */
                    $connection = $this->container->get("doctrine.dbal.{$connectionName}_connection");
                    $all        = $connection->fetchAll($sql);
                    foreach ($all as $option) {
                        $options[] = array(reset($option), end($option));
                    }
                    $item["options"] = $options;
                }

                if (isset($item['service'])) {
                    $serviceInfo = $item['service'];
                    $serviceName = isset($serviceInfo['serviceName']) ? $serviceInfo['serviceName'] : 'default';
                    $method      = isset($serviceInfo['method']) ? $serviceInfo['method'] : 'get';
                    $args        = isset($serviceInfo['args']) ? $item['args'] : '';
                    $service     = $this->container->get($serviceName);
                    $options     = $service->$method($args);

                    $item['options'] = $options;
                }

                if (isset($item['dataStore'])) {
                    $dataStoreInfo = $item['dataStore'];
                    $dataStore     = $this->container->get('data.source')->get($dataStoreInfo["id"]);
                    $options       = array();
                    foreach ($dataStore->search() as $dataItem) {
                        $options[ $dataItem->getId() ] = $dataItem->getAttribute($dataStoreInfo["text"]);
                    }
                    if (isset($item['dataStore']['popupItems'])) {
                        $item['dataStore']['popupItems'] = $this->prepareItems($item['dataStore']['popupItems']);
                    }
                    $item['options'] = $options;
                }
                break;
        }
        return $item;
    }