# 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 hashlib
import ipaddress
from enum import Enum

from asn1crypto.keys import PublicKeyInfo

import six

from cryptography import utils
from cryptography.hazmat.primitives import constant_time, serialization
from cryptography.hazmat.primitives.asymmetric.ec import EllipticCurvePublicKey
from cryptography.hazmat.primitives.asymmetric.rsa import RSAPublicKey
from cryptography.x509.certificate_transparency import (
    SignedCertificateTimestamp
)
from cryptography.x509.general_name import GeneralName, IPAddress, OtherName
from cryptography.x509.name import RelativeDistinguishedName
from cryptography.x509.oid import (
    CRLEntryExtensionOID, ExtensionOID, ObjectIdentifier
)


def _key_identifier_from_public_key(public_key):
    if isinstance(public_key, RSAPublicKey):
        data = public_key.public_bytes(
            serialization.Encoding.DER,
            serialization.PublicFormat.PKCS1,
        )
    elif isinstance(public_key, EllipticCurvePublicKey):
        data = public_key.public_numbers().encode_point()
    else:
        # This is a very slow way to do this.
        serialized = public_key.public_bytes(
            serialization.Encoding.DER,
            serialization.PublicFormat.SubjectPublicKeyInfo
        )

        data = six.binary_type(PublicKeyInfo.load(serialized)['public_key'])

    return hashlib.sha1(data).digest()


class DuplicateExtension(Exception):
    def __init__(self, msg, oid):
        super(DuplicateExtension, self).__init__(msg)
        self.oid = oid


class ExtensionNotFound(Exception):
    def __init__(self, msg, oid):
        super(ExtensionNotFound, self).__init__(msg)
        self.oid = oid


@six.add_metaclass(abc.ABCMeta)
class ExtensionType(object):
    @abc.abstractproperty
    def oid(self):
        """
        Returns the oid associated with the given extension type.
        """


class Extensions(object):
    def __init__(self, extensions):
        self._extensions = extensions

    def get_extension_for_oid(self, oid):
        for ext in self:
            if ext.oid == oid:
                return ext

        raise ExtensionNotFound("No {0} extension was found".format(oid), oid)

    def get_extension_for_class(self, extclass):
        if extclass is UnrecognizedExtension:
            raise TypeError(
                "UnrecognizedExtension can't be used with "
                "get_extension_for_class because more than one instance of the"
                " class may be present."
            )

        for ext in self:
            if isinstance(ext.value, extclass):
                return ext

        raise ExtensionNotFound(
            "No {0} extension was found".format(extclass), extclass.oid
        )

    def __iter__(self):
        return iter(self._extensions)

    def __len__(self):
        return len(self._extensions)

    def __getitem__(self, idx):
        return self._extensions[idx]

    def __repr__(self):
        return (
            "<Extensions({0})>".format(self._extensions)
        )


@utils.register_interface(ExtensionType)
class CRLNumber(object):
    oid = ExtensionOID.CRL_NUMBER

    def __init__(self, crl_number):
        if not isinstance(crl_number, six.integer_types):
            raise TypeError("crl_number must be an integer")

        self._crl_number = crl_number

    def __eq__(self, other):
        if not isinstance(other, CRLNumber):
            return NotImplemented

        return self.crl_number == other.crl_number

    def __ne__(self, other):
        return not self == other

    def __hash__(self):
        return hash(self.crl_number)

    def __repr__(self):
        return "<CRLNumber({0})>".format(self.crl_number)

    crl_number = utils.read_only_property("_crl_number")


@utils.register_interface(ExtensionType)
class AuthorityKeyIdentifier(object):
    oid = ExtensionOID.AUTHORITY_KEY_IDENTIFIER

    def __init__(self, key_identifier, authority_cert_issuer,
                 authority_cert_serial_number):
        if (authority_cert_issuer is None) != (
            authority_cert_serial_number is None
        ):
            raise ValueError(
                "authority_cert_issuer and authority_cert_serial_number "
                "must both be present or both None"
            )

        if authority_cert_issuer is not None:
            authority_cert_issuer = list(authority_cert_issuer)
            if not all(
                isinstance(x, GeneralName) for x in authority_cert_issuer
            ):
                raise TypeError(
                    "authority_cert_issuer must be a list of GeneralName "
                    "objects"
                )

        if authority_cert_serial_number is not None and not isinstance(
            authority_cert_serial_number, six.integer_types
        ):
            raise TypeError(
                "authority_cert_serial_number must be an integer"
            )

        self._key_identifier = key_identifier
        self._authority_cert_issuer = authority_cert_issuer
        self._authority_cert_serial_number = authority_cert_serial_number

    @classmethod
    def from_issuer_public_key(cls, public_key):
        digest = _key_identifier_from_public_key(public_key)
        return cls(
            key_identifier=digest,
            authority_cert_issuer=None,
            authority_cert_serial_number=None
        )

    @classmethod
    def from_issuer_subject_key_identifier(cls, ski):
        return cls(
            key_identifier=ski.value.digest,
            authority_cert_issuer=None,
            authority_cert_serial_number=None
        )

    def __repr__(self):
        return (
            "<AuthorityKeyIdentifier(key_identifier={0.key_identifier!r}, "
            "authority_cert_issuer={0.authority_cert_issuer}, "
            "authority_cert_serial_number={0.authority_cert_serial_number}"
            ")>".format(self)
        )

    def __eq__(self, other):
        if not isinstance(other, AuthorityKeyIdentifier):
            return NotImplemented

        return (
            self.key_identifier == other.key_identifier and
            self.authority_cert_issuer == other.authority_cert_issuer and
            self.authority_cert_serial_number ==
            other.authority_cert_serial_number
        )

    def __ne__(self, other):
        return not self == other

    def __hash__(self):
        if self.authority_cert_issuer is None:
            aci = None
        else:
            aci = tuple(self.authority_cert_issuer)
        return hash((
            self.key_identifier, aci, self.authority_cert_serial_number
        ))

    key_identifier = utils.read_only_property("_key_identifier")
    authority_cert_issuer = utils.read_only_property("_authority_cert_issuer")
    authority_cert_serial_number = utils.read_only_property(
        "_authority_cert_serial_number"
    )


@utils.register_interface(ExtensionType)
class SubjectKeyIdentifier(object):
    oid = ExtensionOID.SUBJECT_KEY_IDENTIFIER

    def __init__(self, digest):
        self._digest = digest

    @classmethod
    def from_public_key(cls, public_key):
        return cls(_key_identifier_from_public_key(public_key))

    digest = utils.read_only_property("_digest")

    def __repr__(self):
        return "<SubjectKeyIdentifier(digest={0!r})>".format(self.digest)

    def __eq__(self, other):
        if not isinstance(other, SubjectKeyIdentifier):
            return NotImplemented

        return constant_time.bytes_eq(self.digest, other.digest)

    def __ne__(self, other):
        return not self == other

    def __hash__(self):
        return hash(self.digest)


@utils.register_interface(ExtensionType)
class AuthorityInformationAccess(object):
    oid = ExtensionOID.AUTHORITY_INFORMATION_ACCESS

    def __init__(self, descriptions):
        descriptions = list(descriptions)
        if not all(isinstance(x, AccessDescription) for x in descriptions):
            raise TypeError(
                "Every item in the descriptions list must be an "
                "AccessDescription"
            )

        self._descriptions = descriptions

    def __iter__(self):
        return iter(self._descriptions)

    def __len__(self):
        return len(self._descriptions)

    def __repr__(self):
        return "<AuthorityInformationAccess({0})>".format(self._descriptions)

    def __eq__(self, other):
        if not isinstance(other, AuthorityInformationAccess):
            return NotImplemented

        return self._descriptions == other._descriptions

    def __ne__(self, other):
        return not self == other

    def __getitem__(self, idx):
        return self._descriptions[idx]

    def __hash__(self):
        return hash(tuple(self._descriptions))


class AccessDescription(object):
    def __init__(self, access_method, access_location):
        if not isinstance(access_method, ObjectIdentifier):
            raise TypeError("access_method must be an ObjectIdentifier")

        if not isinstance(access_location, GeneralName):
            raise TypeError("access_location must be a GeneralName")

        self._access_method = access_method
        self._access_location = access_location

    def __repr__(self):
        return (
            "<AccessDescription(access_method={0.access_method}, access_locati"
            "on={0.access_location})>".format(self)
        )

    def __eq__(self, other):
        if not isinstance(other, AccessDescription):
            return NotImplemented

        return (
            self.access_method == other.access_method and
            self.access_location == other.access_location
        )

    def __ne__(self, other):
        return not self == other

    def __hash__(self):
        return hash((self.access_method, self.access_location))

    access_method = utils.read_only_property("_access_method")
    access_location = utils.read_only_property("_access_location")


@utils.register_interface(ExtensionType)
class BasicConstraints(object):
    oid = ExtensionOID.BASIC_CONSTRAINTS

    def __init__(self, ca, path_length):
        if not isinstance(ca, bool):
            raise TypeError("ca must be a boolean value")

        if path_length is not None and not ca:
            raise ValueError("path_length must be None when ca is False")