class Transports

final class Transports implements TransportInterface {
    
    /**
     * @var array<string, TransportInterface>
     */
    private array $transports = [];
    private TransportInterface $default;
    
    /**
     * @param iterable<string, TransportInterface> $transports
     */
    public function __construct(iterable $transports) {
        foreach ($transports as $name => $transport) {
            $this->default ??= $transport;
            $this->transports[$name] = $transport;
        }
        if (!$this->transports) {
            throw new LogicException(\sprintf('"%s" must have at least one transport configured.', __CLASS__));
        }
    }
    public function send(RawMessage $message, ?Envelope $envelope = null) : ?SentMessage {
        
        /** @var Message $message */
        if (RawMessage::class === $message::class || !$message->getHeaders()
            ->has('X-Transport')) {
            return $this->default
                ->send($message, $envelope);
        }
        $headers = $message->getHeaders();
        $transport = $headers->get('X-Transport')
            ->getBody();
        $headers->remove('X-Transport');
        if (!isset($this->transports[$transport])) {
            throw new InvalidArgumentException(\sprintf('The "%s" transport does not exist (available transports: "%s").', $transport, implode('", "', array_keys($this->transports))));
        }
        try {
            return $this->transports[$transport]
                ->send($message, $envelope);
        } catch (\Throwable $e) {
            $headers->addTextHeader('X-Transport', $transport);
            throw $e;
        }
    }
    public function __toString() : string {
        return '[' . implode(',', array_keys($this->transports)) . ']';
    }

}