protected function autocomplete(string $partialCommand, int $index): array
    {
        // @TODO Add more functionality by parsing the current buffer with readline_info()
        // @TODO Filter file system elements (if possible at all)

        $suggestions = [];

        $availableCommands = $this->bootstrap->getObjectManager()
            ->get(CommandManager::class)
            ->getAvailableCommands();

        /** @var $command Command */
        foreach ($availableCommands as $command) {
            if ($command->isInternal() === false) {
                $suggestions[] = $command->getCommandIdentifier();
            }
        }

        return $suggestions;
    }