import logging

from OpenSSL import SSL
from service_identity.exceptions import CertificateError
from twisted.internet._sslverify import (
    ClientTLSOptions,
    VerificationError,
    verifyHostname,
)
from twisted.internet.ssl import AcceptableCiphers

from scrapy.utils.ssl import get_temp_key_info, x509name_to_string

logger = logging.getLogger(__name__)


METHOD_TLS = "TLS"
METHOD_TLSv10 = "TLSv1.0"
METHOD_TLSv11 = "TLSv1.1"
METHOD_TLSv12 = "TLSv1.2"


openssl_methods = {
    METHOD_TLS: SSL.SSLv23_METHOD,  # protocol negotiation (recommended)
    METHOD_TLSv10: SSL.TLSv1_METHOD,  # TLS 1.0 only
    METHOD_TLSv11: SSL.TLSv1_1_METHOD,  # TLS 1.1 only
    METHOD_TLSv12: SSL.TLSv1_2_METHOD,  # TLS 1.2 only
}


class ScrapyClientTLSOptions(ClientTLSOptions):
    """
    SSL Client connection creator ignoring certificate verification errors
    (for genuinely invalid certificates or bugs in verification code).

    Same as Twisted's private _sslverify.ClientTLSOptions,
    except that VerificationError, CertificateError and ValueError
    exceptions are caught, so that the connection is not closed, only
    logging warnings. Also, HTTPS connection parameters logging is added.
    """

    def __init__(self, hostname, ctx, verbose_logging=False):
        super().__init__(hostname, ctx)
        self.verbose_logging = verbose_logging

    def _identityVerifyingInfoCallback(self, connection, where, ret):
        if where & SSL.SSL_CB_HANDSHAKE_START:
            connection.set_tlsext_host_name(self._hostnameBytes)
        elif where & SSL.SSL_CB_HANDSHAKE_DONE:
            if self.verbose_logging:
                logger.debug(
                    "SSL connection to %s using protocol %s, cipher %s",
                    self._hostnameASCII,
                    connection.get_protocol_version_name(),
                    connection.get_cipher_name(),
                )
                server_cert = connection.get_peer_certificate()
                logger.debug(
                    'SSL connection certificate: issuer "%s", subject "%s"',
                    x509name_to_string(server_cert.get_issuer()),
                    x509name_to_string(server_cert.get_subject()),
                )
                key_info = get_temp_key_info(connection._ssl)
                if key_info:
                    logger.debug("SSL temp key: %s", key_info)

            try:
                verifyHostname(connection, self._hostnameASCII)
            except (CertificateError, VerificationError) as e:
                logger.warning(
                    'Remote certificate is not valid for hostname "%s"; %s',
                    self._hostnameASCII,
                    e,
                )

            except ValueError as e:
                logger.warning(
                    "Ignoring error while verifying certificate "
                    'from host "%s" (exception: %r)',
                    self._hostnameASCII,
                    e,
                )


DEFAULT_CIPHERS = AcceptableCiphers.fromOpenSSLCipherString("DEFAULT")
