# -*- mode: python; coding: utf-8 -*-
# Re2o est un logiciel d'administration développé initiallement au rezometz. Il
# se veut agnostique au réseau considéré, de manière à être installable en
# quelques clics.
#
# Copyright © 2018  Maël Kervella
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

"""api.acl

Here are defined some functions to check acl on the application.
"""


from django.conf import settings
from django.contrib.contenttypes.models import ContentType
from django.contrib.auth.models import Permission


# Creates the 'use_api' permission if not created
# The 'use_api' is a fake permission in the sense
# it is not associated with an existing model and
# this ensure the permission is created every tun
api_content_type, created = ContentType.objects.get_or_create(
    app_label=settings.API_CONTENT_TYPE_APP_LABEL,
    model=settings.API_CONTENT_TYPE_MODEL
)
if created:
    api_content_type.save()
api_permission, created = Permission.objects.get_or_create(
    name=settings.API_PERMISSION_NAME,
    content_type=api_content_type,
    codename=settings.API_PERMISSION_CODENAME
)
if created:
    api_permission.save()


def can_view(user):
    """Check if an user can view the application.

    Args:
        user: The user who wants to view the application.

    Returns:
        A couple (allowed, msg) where allowed is a boolean which is True if
        viewing is granted and msg is a message (can be None).
    """
    kwargs = {
        'app_label': settings.API_CONTENT_TYPE_APP_LABEL,
        'codename': settings.API_PERMISSION_CODENAME
    }
    can = user.has_perm('%(app_label)s.%(codename)s' % kwargs)
    return can, None if can else "Vous ne pouvez pas voir cette application."