@python_2_unicode_compatible
class NotificationQuerySet(models.query.QuerySet):

    def unread(self):
        return self.filter(unread=True).select_related('actor', 'recipient')

    def read(self):
        return self.filter(unread=False).select_related('actor', 'recipient')

    def mark_all_as_read(self, recipient=None):
        """标为已读，可以传入接收者参数"""
        qs = self.unread()
        if recipient:
            qs = qs.filter(recipient=recipient)
        return qs.update(unread=False)

    def mark_all_as_unread(self, recipient=None):
        """标为未读，可以传入接收者参数"""
        qs = self.read()
        if recipient:
            qs = qs.filter(recipient=recipient)
        return qs.update(unread=True)

    def get_most_recent(self, recipient=None):
        """获取最近5条未读通知"""
        qs = self.unread()[:5]
        if recipient:
            qs = qs.filter(recipient=recipient)[:5]
        return qs

    def serialize_latest_notifications(self, recipient=None):
        """序列化最近5条未读通知，可以传入接收者参数"""
        qs = self.get_most_recent(recipient)
        notification_dic = serializers.serialize('json', qs)
        return notification_dic


@python_2_unicode_compatible
class Notification(models.Model):
    """参考：https://github.com/django-notifications/django-notifications"""
    NOTIFICATION_TYPE = (
        ('L', '赞了'),  # like
        ('C', '评论了'),  # comment
        ('F', '收藏了'),  # favor
        ('A', '回答了'),  # answer
        ('W', '接受了回答'),  # accept
        ('R', '回复了'),  # reply
        ('I', '登录'),  # logged in
        ('O', '退出'),  # logged out
    )
    uuid_id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    slug = models.SlugField(max_length=80, null=True, blank=True, verbose_name='(URL)别名')


    actor = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="notify_actor",
                              on_delete=models.CASCADE, verbose_name="触发者")
    verb = models.CharField(max_length=1, choices=NOTIFICATION_TYPE, verbose_name="通知类别")
    recipient = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, blank=False,
                                  related_name="notifications", on_delete=models.CASCADE, verbose_name='接收者')



    created_at = models.DateTimeField(db_index=True, auto_now_add=True, verbose_name='创建时间')
    updated_at = models.DateTimeField(auto_now=True, verbose_name='更新时间')

    content_type = models.ForeignKey(ContentType, related_name='notify_action_object', null=True, blank=True,
                                     on_delete=models.CASCADE)

    object_id = models.CharField(max_length=255, null=True, blank=True)  #可以是news对象 也可以是artice对象
    action_object = GenericForeignKey()
    unread = models.BooleanField(default=True, verbose_name='未读')
    objects = NotificationQuerySet.as_manager()

    class Meta:
        verbose_name = "通知"
        verbose_name_plural = verbose_name
        ordering = ("-created_at",)

    def __str__(self):
        if self.action_object:
            return f'{self.actor} {self.get_verb_display()} {self.action_object}'
        return f'{self.actor} {self.get_verb_display()}'