# Copyright 2012 OpenStack Foundation
#
# 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.

"""Main entry point into the Trust service."""

import abc

from oslo_config import cfg
from oslo_log import log
import six
from six.moves import zip

from keystone.common import dependency
from keystone.common import manager
from keystone import exception
from keystone.i18n import _
from keystone import notifications


CONF = cfg.CONF

LOG = log.getLogger(__name__)


@dependency.requires('identity_api')
@dependency.provider('trust_api')
class Manager(manager.Manager):
    """Default pivot point for the Trust backend.

    See :mod:`keystone.common.manager.Manager` for more details on how this
    dynamically calls the backend.

    """

    driver_namespace = 'keystone.trust'

    _TRUST = "OS-TRUST:trust"

    def __init__(self):
        super(Manager, self).__init__(CONF.trust.driver)

    @staticmethod
    def _validate_redelegation(redelegated_trust, trust):
        # Validate against:
        # 0 < redelegation_count <= max_redelegation_count
        max_redelegation_count = CONF.trust.max_redelegation_count
        redelegation_depth = redelegated_trust.get('redelegation_count', 0)
        if not (0 < redelegation_depth <= max_redelegation_count):
            raise exception.Forbidden(