"""
(c) Copyright 2015-2016 Hewlett-Packard Enterprise Company L.P.

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 functools

from oslo_policy import policy

from freezer_api.common import exceptions
from freezer_api.common import policies


ENFORCER = None


def setup_policy(conf):
    global ENFORCER

    if not ENFORCER:
        ENFORCER = policy.Enforcer(conf)
        ENFORCER.register_defaults(policies.list_rules())
        ENFORCER.load_rules()


def can(rule, ctx, target=None, do_raise=True):
    return ENFORCER.enforce(rule, target or {}, ctx.to_dict(),
                            do_raise=do_raise,
                            exc=exceptions.AccessForbidden)


def enforce(rule):

    def decorator(func):
        @functools.wraps(func)
        def handler(*args, **kwargs):
            req = args[1]
            ctx = req.env['freezer.context']

            target = {}
            if 'project_id' in kwargs:
                target['project_id'] = kwargs['project_id']
            if 'user_id' in kwargs:
                target['user_id'] = kwargs['user_id']
            can(rule, ctx, target=target)
            return func(*args, **kwargs)
        return handler

    return decorator
