# combo - content management system
# Copyright (C) 2014-2019  Entr'ouvert
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from django.conf import settings
from django.contrib.auth.models import User

import django
if django.VERSION < (1, 11, 0):
    CallableFalse, CallableTrue = False, True
else:
    from django.utils.deprecation import CallableFalse, CallableTrue

if 'mellon' in settings.INSTALLED_APPS:
    from mellon.models import UserSAMLIdentifier
else:
    UserSAMLIdentifier = None


class ProxiedUser(object):
    def __init__(self, name_id):
        self.name_id = name_id
        self.email = ''

    def get_name_id(self):
        return self.name_id

    def is_authenticated(self):
        return CallableTrue

    def is_anonymous(self):
        return CallableFalse


def get_user_from_name_id(name_id, raise_on_missing=False):
    if not UserSAMLIdentifier:
        if raise_on_missing:
            raise User.DoesNotExist()
        return None
    try:
        return UserSAMLIdentifier.objects.get(name_id=name_id).user
    except UserSAMLIdentifier.DoesNotExist:
        if raise_on_missing:
            raise User.DoesNotExist()
        return ProxiedUser(name_id=name_id)