# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.

from __future__ import absolute_import, division, print_function

import abc
import datetime
import os
from enum import Enum

import six

from cryptography import utils
from cryptography.hazmat.primitives.asymmetric import dsa, ec, rsa
from cryptography.x509.extensions import Extension, ExtensionType
from cryptography.x509.name import Name


_UNIX_EPOCH = datetime.datetime(1970, 1, 1)


def _convert_to_naive_utc_time(time):
    """Normalizes a datetime to a naive datetime in UTC.

    time -- datetime to normalize. Assumed to be in UTC if not timezone
            aware.
    """
    if time.tzinfo is not None:
        offset = time.utcoffset()
        offset = offset if offset else datetime.timedelta()
        return time.replace(tzinfo=None) - offset
    else:
        return time


class Version(Enum):
    v1 = 0
    v3 = 2


def load_pem_x509_certificate(data, backend):
    return backend.load_pem_x509_certificate(data)


def load_der_x509_certificate(data, backend):
    return backend.load_der_x509_certificate(data)


def load_pem_x509_csr(data, backend):
    return backend.load_pem_x509_csr(data)


def load_der_x509_csr(data, backend):
    return backend.load_der_x509_csr(data)


def load_pem_x509_crl(data, backend):
    return backend.load_pem_x509_crl(data)


def load_der_x509_crl(data, backend):
    return backend.load_der_x509_crl(data)


class InvalidVersion(Exception):
    def __init__(self, msg, parsed_version):
        super(InvalidVersion, self).__init__(msg)
        self.parsed_version = parsed_version


@six.add_metaclass(abc.ABCMeta)
class Certificate(object):
    @abc.abstractmethod
    def fingerprint(self, algorithm):
        """
        Returns bytes using digest passed.
        """

    @abc.abstractproperty
    def serial_number(self):
        """
        Returns certificate serial number
        """

    @abc.abstractproperty
    def version(self):
        """
        Returns the certificate version
        """

    @abc.abstractmethod
    def public_key(self):
        """
        Returns the public key
        """

    @abc.abstractproperty
    def not_valid_before(self):
        """
        Not before time (represented as UTC datetime)
        """

    @abc.abstractproperty
    def not_valid_after(self):
        """
        Not after time (represented as UTC datetime)
        """

    @abc.abstractproperty
    def issuer(self):
        """
        Returns the issuer name object.
        """

    @abc.abstractproperty
    def subject(self):
        """
        Returns the subject name object.
        """

    @abc.abstractproperty
    def signature_hash_algorithm(self):
        """
        Returns a HashAlgorithm corresponding to the type of the digest signed
        in the certificate.
        """

    @abc.abstractproperty
    def signature_algorithm_oid(self):
        """
        Returns the ObjectIdentifier of the signature algorithm.
        """

    @abc.abstractproperty
    def extensions(self):
        """
        Returns an Extensions object.
        """

    @abc.abstractproperty
    def signature(self):
        """
        Returns the signature bytes.
        """

    @abc.abstractproperty
    def tbs_certificate_bytes(self):
        """
        Returns the tbsCertificate payload bytes as defined in RFC 5280.
        """

    @abc.abstractmethod
    def __eq__(self, other):
        """
        Checks equality.
        """

    @abc.abstractmethod
    def __ne__(self, other):
        """
        Checks not equal.
        """

    @abc.abstractmethod
    def __hash__(self):
        """
        Computes a hash.
        """

    @abc.abstractmethod
    def public_bytes(self, encoding):
        """
        Serializes the certificate to PEM or DER format.
        """


@six.add_metaclass(abc.ABCMeta)
class CertificateRevocationList(object):
    @abc.abstractmethod
    def public_bytes(self, encoding):
        """
        Serializes the CRL to PEM or DER format.
        """

    @abc.abstractmethod
    def fingerprint(self, algorithm):
        """
        Returns bytes using digest passed.
        """

    @abc.abstractproperty
    def signature_hash_algorithm(self):
        """
        Returns a HashAlgorithm corresponding to the type of the digest signed
        in the certificate.
        """

    @abc.abstractproperty
    def signature_algorithm_oid(self):
        """
        Returns the ObjectIdentifier of the signature algorithm.
        """

    @abc.abstractproperty
    def issuer(self):
        """
        Returns the X509Name with the issuer of this CRL.
        """

    @abc.abstractproperty
    def next_update(self):
        """
        Returns the date of next update for this CRL.
        """

    @abc.abstractproperty
    def last_update(self):
        """
        Returns the date of last update for this CRL.
        """

    @abc.abstractproperty
    def extensions(self):
        """
        Returns an Extensions object containing a list of CRL extensions.
        """

    @abc.abstractproperty
    def signature(self):
        """
        Returns the signature bytes.
        """

    @abc.abstractproperty
    def tbs_certlist_bytes(self):
        """
        Returns the tbsCertList payload bytes as defined in RFC 5280.
        """

    @abc.abstractmethod
    def __eq__(self, other):
        """
        Checks equality.
        """

    @abc.abstractmethod
    def __ne__(self, other):
        """
        Checks not equal.
        """

    @abc.abstractmethod
    def is_signature_valid(self, public_key):
        """
        Verifies signature of revocation list against given public key.
        """


@six.add_metaclass(abc.ABCMeta)
class CertificateSigningRequest(object):
    @abc.abstractmethod
    def __eq__(self, other):
        """
        Checks equality.
        """

    @abc.abstractmethod
    def __ne__(self, other):
        """
        Checks not equal.
        """

    @abc.abstractmethod
    def __hash__(self):
        """
        Computes a hash.
        """

    @abc.abstractmethod
    def public_key(self):
        """
        Returns the public key
        """

    @abc.abstractproperty
    def subject(self):
        """
        Returns the subject name object.
        """

    @abc.abstractproperty
    def signature_hash_algorithm(self):
        """
        Returns a HashAlgorithm corresponding to the type of the digest signed
        in the certificate.
        """

    @abc.abstractproperty
    def signature_algorithm_oid(self):
        """
        Returns the ObjectIdentifier of the signature algorithm.
        """

    @abc.abstractproperty
    def extensions(self):
        """
        Returns the extensions in the signing request.
        """

    @abc.abstractmethod
    def public_bytes(self, encoding):
        """
        Encodes the request to PEM or DER format.
        """

    @abc.abstractproperty
    def signature(self):
        """
        Returns the signature bytes.
        """

    @abc.abstractproperty
    def tbs_certrequest_bytes(self):
        """
        Returns the PKCS#10 CertificationRequestInfo bytes as defined in RFC
        2986.
        """

    @abc.abstractproperty
    def is_signature_valid(self):
        """
        Verifies signature of signing request.
        """


@six.add_metaclass(abc.ABCMeta)
class RevokedCertificate(object):
    @abc.abstractproperty
    def serial_number(self):
        """
        Returns the serial number of the revoked certificate.
        """

    @abc.abstractproperty