class SMimeEncrypter

final class SMimeEncrypter extends SMime {
    private string|array $certs;
    private int $cipher;
    
    /**
     * @param string|string[] $certificate The path (or array of paths) of the file(s) containing the X.509 certificate(s)
     * @param int|null        $cipher      A set of algorithms used to encrypt the message. Must be one of these PHP constants: https://www.php.net/manual/en/openssl.ciphers.php
     */
    public function __construct(string|array $certificate, ?int $cipher = null) {
        if (!\extension_loaded('openssl')) {
            throw new \LogicException('PHP extension "openssl" is required to use SMime.');
        }
        if (\is_array($certificate)) {
            $this->certs = array_map($this->normalizeFilePath(...), $certificate);
        }
        else {
            $this->certs = $this->normalizeFilePath($certificate);
        }
        $this->cipher = $cipher ?? \OPENSSL_CIPHER_AES_256_CBC;
    }
    public function encrypt(Message $message) : Message {
        $bufferFile = tmpfile();
        $outputFile = tmpfile();
        $this->iteratorToFile($message->toIterable(), $bufferFile);
        if (!@openssl_pkcs7_encrypt(stream_get_meta_data($bufferFile)['uri'], stream_get_meta_data($outputFile)['uri'], $this->certs, [], 0, $this->cipher)) {
            throw new RuntimeException(\sprintf('Failed to encrypt S/Mime message. Error: "%s".', openssl_error_string()));
        }
        $mimePart = $this->convertMessageToSMimePart($outputFile, 'application', 'pkcs7-mime');
        $mimePart->getHeaders()
            ->addTextHeader('Content-Transfer-Encoding', 'base64')
            ->addParameterizedHeader('Content-Disposition', 'attachment', [
            'name' => 'smime.p7m',
        ]);
        return new Message($message->getHeaders(), $mimePart);
    }

}