# -*- coding: utf-8 -*
#
# combo - content management system
# Copyright (C) 2015-2018  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/>.

import base64
import json

from django.conf import settings
from django.core import serializers
from django.core.files.base import ContentFile
from django.core.files.storage import default_storage
from django.db import models
from django.utils import six
from django.utils.encoding import force_text, force_bytes
from django.utils.six import BytesIO
from django.utils.translation import ugettext_lazy as _

from jsonfield import JSONField
from combo.data.fields import RichTextField
from combo import utils


class PwaSettings(models.Model):
    APPLICATION_ICON_SIZES = ['%sx%s' % (x, x) for x in (48, 96, 192, 256, 512)]
    application_icon = models.FileField(
            verbose_name=_('Application Icon'),
            help_text=_(u'Should be a square of at least 512×512 pixels.'),
            upload_to='pwa',
            blank=True,
            null=True)
    offline_text = RichTextField(
            verbose_name=_('Offline Information Text'),
            default=_('You are currently offline.'),
            config_name='small')
    offline_retry_button = models.BooleanField(_('Include Retry Button'), default=True)
    last_update_timestamp = models.DateTimeField(auto_now=True)

    @classmethod
    def singleton(cls):
        return cls.objects.first() or cls()

    @classmethod
    def export_for_json(cls):
        obj = cls.singleton()
        if not obj.id:
            return {}
        serialized_settings = json.loads(serializers.serialize('json', [obj]))
        return serialized_settings[0].get('fields')

    @classmethod
    def load_serialized_settings(cls, json_settings):
        if not json_settings:
            return

        obj = cls.singleton()
        for attr in json_settings:
            setattr(obj, attr, json_settings[attr])
        obj.save()


class PwaNavigationEntry(models.Model):
    label = models.CharField(verbose_name=_('Label'), max_length=150, blank=True)
    url = models.CharField(verbose_name=_('External URL'), max_length=200, blank=True)
    link_page = models.ForeignKey('data.Page', blank=True,
            null=True, verbose_name=_('Internal link'))
    icon = models.FileField(_('Icon'), upload_to='pwa', blank=True, null=True)
    extra_css_class = models.CharField(_('Extra classes for CSS styling'), max_length=100, blank=True)
    order = models.PositiveIntegerField()

    notification_count = models.BooleanField(
            verbose_name=_('Display notification count'),
            default=False)
    use_user_name_as_label = models.BooleanField(
            verbose_name=_('Use user name as label'),
            default=False)

    class Meta:
        ordering = ('order',)

    def get_label(self):
        return self.label or self.link_page.title

    def get_url(self):
        if self.link_page:
            return self.link_page.get_online_url()
        else:
            return utils.get_templated_url(self.url)

    def css_class_names(self):
        css_class_names = self.extra_css_class or ''
        if self.link_page:
            css_class_names += ' page-%s' % self.link_page.slug
        return css_class_names

    @classmethod
    def export_all_for_json(cls):
        return [x.get_as_serialized_object() for x in cls.objects.all()]

    def get_as_serialized_object(self):
        serialized_entry = json.loads(serializers.serialize('json', [self],
            use_natural_foreign_keys=True, use_natural_primary_keys=True))[0]
        if self.icon:
            encode = base64.encodestring if six.PY2 else base64.encodebytes
            serialized_entry['icon:base64'] = force_text(encode(self.icon.read()))
        del serialized_entry['model']
        del serialized_entry['pk']
        return serialized_entry

    @classmethod
    def load_serialized_objects(cls, json_site):
        for json_entry in json_site:
            cls.load_serialized_object(json_entry)

    @classmethod
    def load_serialized_object(cls, json_entry):
        json_entry['model'] = 'pwa.pwanavigationentry'
        # deserialize once to get link_page by natural key
        fake_entry = [x for x in serializers.deserialize('json', json.dumps([json_entry]))][0]
        entry, created = cls.objects.get_or_create(
                label=json_entry['fields']['label'],
                url=json_entry['fields']['url'],
                link_page=fake_entry.object.link_page,
                defaults={'order': 0})
        json_entry['pk'] = entry.id
        entry = [x for x in serializers.deserialize('json', json.dumps([json_entry]))][0]
        entry.save()
        if json_entry.get('icon:base64'):
            decode = base64.decodestring if six.PY2 else base64.decodebytes
            decoded_icon = decode(force_bytes(json_entry['icon:base64']))
            if not default_storage.exists(entry.object.icon.name) or entry.object.icon.read() != decoded_icon:
                # save new file
                entry.object.icon.save(entry.object.icon.name, ContentFile(decoded_icon))


class PushSubscription(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    subscription_info = JSONField()
    creation_timestamp = models.DateTimeField(auto_now_add=True)