# 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.

"""Oauth authentication plugins.

.. warning::
    This module requires installation of an extra package (`oauthlib`)
    not installed by default. Without the extra package an import error will
    occur. The extra package can be installed using::

      $ pip install keystoneauth['oauth1']

"""

import logging

try:
    from oauthlib import oauth1
except ImportError:
    oauth1 = None

from keystoneauth1.identity import v3

__all__ = ('OAuth1Method', 'OAuth1')

LOG = logging.getLogger(__name__)


class OAuth1Method(v3.AuthMethod):
    """OAuth based authentication method.

    :param string consumer_key: Consumer key.
    :param string consumer_secret: Consumer secret.
    :param string access_key: Access token key.
    :param string access_secret: Access token secret.
    """

    _method_parameters = ['consumer_key', 'consumer_secret',
                          'access_key', 'access_secret']

    def get_auth_data(self, session, auth, headers, **kwargs):
        # Add the oauth specific content into the headers
        oauth_client = oauth1.Client(self.consumer_key,
                                     client_secret=self.consumer_secret,
                                     resource_owner_key=self.access_key,
                                     resource_owner_secret=self.access_secret,
                                     signature_method=oauth1.SIGNATURE_HMAC)

        o_url, o_headers, o_body = oauth_client.sign(auth.token_url,
                                                     http_method='POST')
        headers.update(o_headers)

        return 'oauth1', {}

    def get_cache_id_elements(self):
        return dict(('oauth1_%s' % p, getattr(self, p))
                    for p in self._method_parameters)


class OAuth1(v3.AuthConstructor):

    _auth_method_class = OAuth1Method

    def __init__(self, *args, **kwargs):
        super(OAuth1, self).__init__(*args, **kwargs)

        if self.has_scope_parameters:
            LOG.warning('Scoping parameters such as a project were provided '
                        'to the OAuth1 plugin. Because OAuth1 access is '
                        'always scoped to a project these will be ignored by '
                        'the identity server')