class DumpServer

class DumpServer {
    private string $host;
    
    /**
     * @var resource|null
     */
    private $socket;
    public function __construct(string $host, ?LoggerInterface $logger = null) {
        if (!str_contains($host, '://')) {
            $host = 'tcp://' . $host;
        }
        $this->host = $host;
    }
    public function start() : void {
        if (!($this->socket = stream_socket_server($this->host, $errno, $errstr))) {
            throw new \RuntimeException(\sprintf('Server start failed on "%s": ', $this->host) . $errstr . ' ' . $errno);
        }
    }
    public function listen(callable $callback) : void {
        if (null === $this->socket) {
            $this->start();
        }
        foreach ($this->getMessages() as $clientId => $message) {
            $this->logger?->info('Received a payload from client {clientId}', [
                'clientId' => $clientId,
            ]);
            $payload = @unserialize(base64_decode($message), [
                'allowed_classes' => [
                    Data::class,
                    Stub::class,
                ],
            ]);
            // Impossible to decode the message, give up.
            if (false === $payload) {
                $this->logger?->warning('Unable to decode a message from {clientId} client.', [
                    'clientId' => $clientId,
                ]);
                continue;
            }
            if (!\is_array($payload) || \count($payload) < 2 || !$payload[0] instanceof Data || !\is_array($payload[1])) {
                $this->logger?->warning('Invalid payload from {clientId} client. Expected an array of two elements (Data $data, array $context)', [
                    'clientId' => $clientId,
                ]);
                continue;
            }
            [
                $data,
                $context,
            ] = $payload;
            $callback($data, $context, $clientId);
        }
    }
    public function getHost() : string {
        return $this->host;
    }
    private function getMessages() : iterable {
        $sockets = [
            (int) $this->socket => $this->socket,
        ];
        $write = [];
        while (true) {
            $read = $sockets;
            stream_select($read, $write, $write, null);
            foreach ($read as $stream) {
                if ($this->socket === $stream) {
                    $stream = stream_socket_accept($this->socket);
                    $sockets[(int) $stream] = $stream;
                }
                elseif (feof($stream)) {
                    unset($sockets[(int) $stream]);
                    fclose($stream);
                }
                else {
                    (yield (int) $stream => fgets($stream));
                }
            }
        }
    }

}