# 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.

import base64
import typing as ty

from keystoneauth1 import plugin

if ty.TYPE_CHECKING:
    from keystoneauth1 import session as ks_session

AUTH_HEADER_NAME = 'Authorization'


class HTTPBasicAuth(plugin.FixedEndpointPlugin):
    """A provider that will always use HTTP Basic authentication.

    This is useful to unify session/adapter loading for services
    that might be deployed in standalone mode.
    """

    def __init__(
        self,
        endpoint: ty.Optional[str] = None,
        username: ty.Optional[str] = None,
        password: ty.Optional[str] = None,
    ):
        super().__init__(endpoint)
        self.username = username
        self.password = password

    def get_token(self, session: 'ks_session.Session') -> ty.Optional[str]:
        if self.username is None or self.password is None:
            return None
        token = bytes(f'{self.username}:{self.password}', encoding='utf-8')
        encoded = base64.b64encode(token)
        return str(encoded, encoding='utf-8')

    def get_headers(
        self, session: 'ks_session.Session'
    ) -> ty.Optional[dict[str, str]]:
        token = self.get_token(session)
        if not token:
            return None
        auth = f'Basic {token}'
        return {AUTH_HEADER_NAME: auth}
