# Copyright 2014-2015 MongoDB, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you
# may not use this file except in compliance with the License.  You
# may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.  See the License for the specific language governing
# permissions and limitations under the License.

"""A fake SSLContext implementation."""

try:
    import ssl
except ImportError:
    pass


class SSLContext(object):
    """A fake SSLContext.

    This implements an API similar to ssl.SSLContext from python 3.2
    but does not implement methods or properties that would be
    incompatible with ssl.wrap_socket from python 2.6.

    You must pass protocol which must be one of the PROTOCOL_* constants
    defined in the ssl module. ssl.PROTOCOL_SSLv23 is recommended for maximum
    interoperability.
    """

    __slots__ = ('_cafile', '_certfile',
                 '_keyfile', '_protocol', '_verify_mode')

    def __init__(self, protocol):
        self._cafile = None
        self._certfile = None
        self._keyfile = None
        self._protocol = protocol
        self._verify_mode = ssl.CERT_NONE

    @property
    def protocol(self):
        """The protocol version chosen when constructing the context.
        This attribute is read-only.
        """
        return self._protocol

    def __get_verify_mode(self):
        """Whether to try to verify other peers' certificates and how to
        behave if verification fails. This attribute must be one of
        ssl.CERT_NONE, ssl.CERT_OPTIONAL or ssl.CERT_REQUIRED.
        """
        return self._verify_mode

    def __set_verify_mode(self, value):
        """Setter for verify_mode."""
        self._verify_mode = value

    verify_mode = property(__get_verify_mode, __set_verify_mode)

    def load_cert_chain(self, certfile, keyfile=None):
        """Load a private key and the corresponding certificate. The certfile
        string must be the path to a single file in PEM format containing the
        certificate as well as any number of CA certificates needed to
        establish the certificate's authenticity. The keyfile string, if
        present, must point to a file containing the private key. Otherwise
        the private key will be taken from certfile as well.
        """
        self._certfile = certfile
        self._keyfile = keyfile

    def load_verify_locations(self, cafile=None, dummy=None):
        """Load a set of "certification authority"(CA) certificates used to
        validate other peers' certificates when `~verify_mode` is other than
        ssl.CERT_NONE.
        """
        self._cafile = cafile

    def wrap_socket(self, sock, server_side=False,
                    do_handshake_on_connect=True,
                    suppress_ragged_eofs=True, dummy=None):
        """Wrap an existing Python socket sock and return an ssl.SSLSocket
        object.
        """
        return ssl.wrap_socket(sock, keyfile=self._keyfile,
                               certfile=self._certfile,
                               server_side=server_side,
                               cert_reqs=self._verify_mode,
                               ssl_version=self._protocol,
                               ca_certs=self._cafile,
                               do_handshake_on_connect=do_handshake_on_connect,
                               suppress_ragged_eofs=suppress_ragged_eofs)

