Django-ORM多重distinct和order by

我在开发一个简单的聊天软件。我需要查询数据库中的一个用户,以获取用户对话的最后一条消息给其他用户。与whatsapp和telegram的主页相同。

型号:

class CHAT(models.Model):
    sender_uid = models.CharField(max_length=150, db_index=True)
    receiver_uid = models.CharField(max_length=150, db_index=True)
    message = models.TextField(verbose_name='Message Text')
    created = models.IntegerField(default=created_time_epoch)

message_list = self.model.objects.filter(Q(sender_uid=user_uid)|Q(receiver_uid=user_uid)).order_by('receiver_uid', 'sender_uid', '-created').distinct('receiver_uid', 'sender_uid')

输出:

<QuerySet [<CHAT: ted@ted.com Message: hello 4 To: saeed@saeed.com>, <CHAT: marshal@marshal.com Message: hello6 To: saeed@saeed.com>, <CHAT: saeed@saeed.com Message: hello 5 To: ted@ted.com>]>

现在我用下面的代码来处理它:

message_send_list = list(self.model.objects.filter(sender_uid=user_uid).order_by('receiver_uid', '-created').distinct('receiver_uid'))
message_receive_list = list(self.model.objects.filter(receiver_uid=user_uid).order_by('sender_uid', '-created').distinct('sender_uid'))
temp_list = []
for s_message in message_send_list:
    r_message = next((item for item in message_receive_list if item.sender_uid == s_message.receiver_uid), None)
    if r_message is not None:
        message_receive_list.pop(message_receive_list.index(r_message))
        if s_message.created > r_message.created:
            temp_list.append(s_message)
        else:
             temp_list.append(r_message)
    else:
        temp_list.append(s_message)
temp_list.extend(message_receive_list)

[<CHAT: saeed@saeed.com Message: hello 5 To: ted@ted.com>, <CHAT: marshal@marshal.com Message: hello6 To: saeed@saeed.com>]

我的问题是如何在一个查询中得到这个结果?问题是用户可以是消息的发送者和接收者,我无法区分哪一个是会话的最后一条消息。如何过滤或区分?