# Copyright 2012 OpenStack Foundation.
# All Rights Reserved.
#
#    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.

"""Context: context for security/db session."""

import copy
import datetime

from oslo_context import context as oslo_context
from oslo_log import log as logging

from neutron.db import api as db_api
from neutron import policy


LOG = logging.getLogger(__name__)


class ContextBase(oslo_context.RequestContext):
    """Security context and request information.

    Represents the user taking a given action within the system.

    """

    def __init__(self, user_id, tenant_id, is_admin=None, read_deleted="no",
                 roles=None, timestamp=None, load_admin_roles=True,
                 request_id=None, tenant_name=None, user_name=None,
                 overwrite=True, auth_token=None, **kwargs):
        """Object initialization.

        :param read_deleted: 'no' indicates deleted records are hidden, 'yes'
            indicates deleted records are visible, 'only' indicates that
            *only* deleted records are visible.

        :param overwrite: Set to False to ensure that the greenthread local
            copy of the index is not overwritten.

        :param kwargs: Extra arguments that might be present, but we ignore
            because they possibly came in from older rpc messages.
        """
        super(ContextBase, self).__init__(auth_token=auth_token,
                                          user=user_id, tenant=tenant_id,
                                          is_admin=is_admin,
                                          request_id=request_id,
                                          overwrite=overwrite)
        self.user_name = user_name
        self.tenant_name = tenant_name

        self.read_deleted = read_deleted
        if not timestamp:
            timestamp = datetime.datetime.utcnow()
        self.timestamp = timestamp
        self._session = None
        self.roles = roles or []
        self.is_advsvc = policy.check_is_advsvc(self)
        if self.is_admin is None:
            self.is_admin = policy.check_is_admin(self)
        elif self.is_admin and load_admin_roles:
            # Ensure context is populated with admin roles
            admin_roles = policy.get_admin_roles()
            if admin_roles:
                self.roles = list(set(self.roles) | set(admin_roles))
        # Log only once the context has been configured to prevent
        # format errors.
        if kwargs:
            LOG.debug('Arguments dropped when creating context: %s', kwargs)

    @property
    def project_id(self):
        return self.tenant

    @property
    def tenant_id(self):
        return self.tenant

    @tenant_id.setter
    def tenant_id(self, tenant_id):
        self.tenant = tenant_id

    @property
    def user_id(self):
        return self.user

    @user_id.setter
    def user_id(self, user_id):
        self.user = user_id

    def _get_read_deleted(self):
        return self._read_deleted

    def _set_read_deleted(self, read_deleted):
        if read_deleted not in ('no', 'yes', 'only'):
            raise ValueError(_("read_deleted can only be one of 'no', "
                               "'yes' or 'only', not %r") % read_deleted)
        self._read_deleted = read_deleted

    def _del_read_deleted(self):
        del self._read_deleted

    read_deleted = property(_get_read_deleted, _set_read_deleted,
                            _del_read_deleted)

    def to_dict(self):
        return {'user_id': self.user_id,
                'tenant_id': self.tenant_id,
                'project_id': self.project_id,
                'is_admin': self.is_admin,
                'read_deleted': self.read_deleted,
                'roles': self.roles,
                'timestamp': str(self.timestamp),
                'request_id': self.request_id,
                'tenant': self.tenant,
                'user': self.user,
                'tenant_name': self.tenant_name,
                'project_name': self.tenant_name,
                'user_name': self.user_name,
                'auth_token': self.auth_token,
                }

    @classmethod
    def from_dict(cls, values):
        return cls(**values)

    def elevated(self, read_deleted=None):
        """Return a version of this context with admin flag set."""
        context = copy.copy(self)
        context.is_admin = True

        if 'admin' not in [x.lower() for x in context.roles]:
            context.roles = context.roles + ["admin"]

        if read_deleted is not None:
            context.read_deleted = read_deleted

        return context


class Context(ContextBase):
    @property
    def session(self):
        if self._session is None:
            self._session = db_api.get_session()
        return self._session


def get_admin_context(read_deleted="no", load_admin_roles=True):
    return Context(user_id=None,
                   tenant_id=None,
                   is_admin=True,
                   read_deleted=read_deleted,
                   load_admin_roles=load_admin_roles,
                   overwrite=False)


def get_admin_context_without_session(read_deleted="no"):
    return ContextBase(user_id=None,
                       tenant_id=None,
                       is_admin=True,
                       read_deleted=read_deleted)
