# fargo - document box
# Copyright (C) 2016-2019  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/>.

import uuid
import datetime

from django.conf import settings
from django.core.exceptions import ValidationError
from django.core.validators import URLValidator
from django.db import models
from django.utils.encoding import python_2_unicode_compatible
from django.utils.translation import ugettext_lazy as _
from django.db.models.query import QuerySet
from django.utils.timezone import now

from fargo.fargo.models import Document, UserDocument


def generate_uuid():
    return uuid.uuid4().hex


def validate_https_url(data):
    errors = []
    data = data.strip()
    if not data:
        return
    for url in data.split():
        try:
            URLValidator(schemes=['http', 'https'])(url)
        except ValidationError as e:
            errors.append(e)
    if errors:
        raise ValidationError(errors)


@python_2_unicode_compatible
class OAuth2Client(models.Model):
    client_name = models.CharField(max_length=255)
    redirect_uris = models.TextField(
        verbose_name=_('redirect URIs'),
        validators=[validate_https_url])
    client_id = models.CharField(max_length=255, default=generate_uuid)
    client_secret = models.CharField(max_length=255, default=generate_uuid)

    def __repr__(self):
        return 'OAuth2Client name: %s with id: %s' % (self.client_name, self.client_id)

    def get_redirect_uris(self):
        return self.redirect_uris.split()

    def check_redirect_uri(self, redirect_uri):
        return redirect_uri in self.redirect_uris.strip().split()

    def __str__(self):
        return self.client_name

    class Meta:
        ordering = ('client_name',)
        verbose_name = _('OAUTH2 client')
        verbose_name_plural = _('OAUTH2 clients')


class CleanupQuerySet(QuerySet):
    def cleanup(self, n=None):
        n = n or now()
        threshold = n - datetime.timedelta(seconds=2 * self.model.get_lifetime())
        self.filter(creation_date__lt=threshold).delete()


class OAuth2Authorize(models.Model):
    client = models.ForeignKey(OAuth2Client)
    user_document = models.ForeignKey(UserDocument)
    access_token = models.CharField(max_length=255, default=generate_uuid)
    code = models.CharField(max_length=255, default=generate_uuid)
    creation_date = models.DateTimeField(auto_now_add=True)

    objects = CleanupQuerySet.as_manager()

    class Meta:
        ordering = ('creation_date',)
        verbose_name = _('OAUTH2 authorization')
        verbose_name_plural = _('OAUTH2 authorizations')

    @classmethod
    def get_lifetime(cls):
        return max(
            settings.FARGO_CODE_LIFETIME,
            settings.FARGO_ACCESS_TOKEN_LIFETIME)

    def __repr__(self):
        return 'OAuth2Authorize for document %r' % self.user_document


class OAuth2TempFile(models.Model):
    uuid = models.CharField(max_length=32, default=generate_uuid, primary_key=True)
    client = models.ForeignKey(OAuth2Client)
    document = models.ForeignKey(Document, related_name='oauth2_tempfiles')
    filename = models.CharField(max_length=512)
    creation_date = models.DateTimeField(auto_now_add=True)

    objects = CleanupQuerySet.as_manager()

    @classmethod
    def get_lifetime(cls):
        return settings.FARGO_OAUTH2_TEMPFILE_LIFETIME

    class Meta:
        ordering = ('creation_date',)
        verbose_name = _('OAUTH2 temporary file')
        verbose_name_plural = _('OAUTH2 temporary files')