Fix sorting of message lists

This should really be done on the database end, but this is a simple fix
for the sorting being wrong (due to last_reply_time not being set for
single-message conversations).

tildes/tildes/views/message.py

@@ -7,7 +7,7 @@ from pyramid.httpexceptions import HTTPFound
 from pyramid.request import Request
 from pyramid.view import view_config
 from sqlalchemy.dialects.postgresql import array
-from sqlalchemy.sql.expression import and_, desc, or_
+from sqlalchemy.sql.expression import and_, or_
 from webargs.pyramidparser import use_kwargs
 
 from tildes.models.message import MessageConversation, MessageReply
@@ -39,10 +39,11 @@ def get_user_messages(request: Request) -> dict:
                 ),
             )
         )
-        .order_by(desc(MessageConversation.last_reply_time))
         .all()
     )
 
+    conversations.sort(key=lambda c: c.last_activity_time, reverse=True)
+
     return {"conversations": conversations}
 
 
@@ -56,10 +57,11 @@ def get_user_unread_messages(request: Request) -> dict:
                 array([request.user.user_id])
             )
         )
-        .order_by(desc(MessageConversation.last_reply_time))
         .all()
     )
 
+    conversations.sort(key=lambda c: c.last_activity_time, reverse=True)
+
     return {"conversations": conversations}
 
 
@@ -79,10 +81,11 @@ def get_user_sent_messages(request: Request) -> dict:
                 ),
             )
         )
-        .order_by(desc(MessageConversation.last_reply_time))
         .all()
     )
 
+    conversations.sort(key=lambda c: c.last_activity_time, reverse=True)
+
     return {"conversations": conversations}