# combo - content management system
# Copyright (C) 2017  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.contrib.auth.models import Group
from django.db import transaction
from django.utils import six
from django.utils.encoding import python_2_unicode_compatible
from django.utils.translation import ugettext_lazy as _

from combo.apps.assets.models import Asset
from combo.apps.maps.models import MapLayer
from combo.apps.pwa.models import PwaSettings, PwaNavigationEntry
from .models import Page


@python_2_unicode_compatible
class MissingGroups(Exception):
    def __init__(self, names):
        self.names = names

    def __str__(self):
        return _('Missing groups: %s') % ', '.join(self.names)


def export_site():
    '''Dump site objects to JSON-dumpable dictionnary'''
    return {'pages': Page.export_all_for_json(),
            'map-layers': MapLayer.export_all_for_json(),
            'assets': Asset.export_all_for_json(),
            'pwa': {
                'settings': PwaSettings.export_for_json(),
                'navigation': PwaNavigationEntry.export_all_for_json(),
            }
           }


def import_site(data, if_empty=False, clean=False):
    if isinstance(data, list):
        # old export form with a list of pages, convert it to new dictionary
        # format.
        data = {'pages': data}

    if if_empty and (Page.objects.count() or MapLayer.objects.count()):
        return

    # check groups used in access control are all available.
    groups = set()
    for page in data.get('pages') or []:
        for group in page['fields']['groups']:
            groups.add(group if isinstance(group, six.string_types) else group[0])
        for cell in page['cells']:
            for group in cell['fields']['groups']:
                groups.add(group if isinstance(group, six.string_types) else group[0])

    existing_groups = set([x.name for x in Group.objects.filter(name__in=groups)])
    missing_groups = groups - existing_groups
    if missing_groups:
        raise MissingGroups(names=sorted([x for x in missing_groups]))

    with transaction.atomic():
        if clean:
            MapLayer.objects.all().delete()
            Asset.objects.all().delete()
            Page.objects.all().delete()
            PwaSettings.objects.all().delete()
            PwaNavigationEntry.objects.all().delete()

        MapLayer.load_serialized_objects(data.get('map-layers') or [])
        Asset.load_serialized_objects(data.get('assets') or [])
        Page.load_serialized_pages(data.get('pages') or [])

        if data.get('pwa'):
            PwaSettings.load_serialized_settings(data['pwa'].get('settings'))
            PwaNavigationEntry.load_serialized_objects(data['pwa'].get('navigation'))