# 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.

"""Keystone Compressed PKI Token Provider"""

from keystoneclient.common import cms
from oslo_config import cfg
from oslo_log import log
from oslo_serialization import jsonutils

from keystone.common import environment
from keystone.common import utils
from keystone import exception
from keystone.i18n import _
from keystone.token.providers import common


CONF = cfg.CONF

LOG = log.getLogger(__name__)
ERROR_MESSAGE = _('Unable to sign token.')


class Provider(common.BaseProvider):
    def _get_token_id(self, token_data):
        try:
            # force conversion to a string as the keystone client cms code
            # produces unicode. This can be removed if the client returns
            # str()
            # TODO(ayoung): Make to a byte_str for Python3
            token_json = jsonutils.dumps(token_data, cls=utils.PKIEncoder)
            token_id = str(cms.pkiz_sign(token_json,
                                         CONF.signing.certfile,
                                         CONF.signing.keyfile))
            return token_id
        except environment.subprocess.CalledProcessError:
            LOG.exception(ERROR_MESSAGE)
            raise exception.UnexpectedError(ERROR_MESSAGE)

    @property
    def _supports_bind_authentication(self):
        """Return if the token provider supports bind authentication methods.

        :returns: True
        """
        return True

    def needs_persistence(self):
        """Should the token be written to a backend."""
        return True