protected function createCommand($commandName, array $commandDca)
    {

        $command = $this->createCommandInstance($commandName, $commandDca);
        $command->setName($commandName);

        $parameters = $command->getParameters();

        if (isset($commandDca['href'])) {
            \parse_str($commandDca['href'], $queryParameters);
            foreach ($queryParameters as $name => $value) {
                $parameters[$name] = $value;
            }
            unset($commandDca['href']);
        }

        if (isset($commandDca['parameters'])) {
            foreach ($commandDca['parameters'] as $name => $value) {
                $parameters[$name] = $value;
            }
            unset($commandDca['parameters']);
        }

        if (isset($commandDca['label'])) {
            $lang = $commandDca['label'];

            if (\is_array($lang)) {
                $label       = \reset($lang);
                $description = \next($lang);

                $command->setDescription($description);
            } else {
                $label = $lang;
            }

            $command->setLabel($label);

            unset($commandDca['label']);
        }

        if (isset($commandDca['description'])) {
            $command->setDescription($commandDca['description']);

            unset($commandDca['description']);
        }

        // Callback is transformed into event in parseCallbacks().
        unset($commandDca['button_callback']);

        if (\count($commandDca)) {
            $extra = $command->getExtra();

            foreach ($commandDca as $name => $value) {
                $extra[$name] = $value;
            }
        }

        return $command;
    }