chat: proper fork behavior in backend, wip frontend

backend/src/app_mixins/chat.py

@@ -17,6 +17,25 @@ def message_json(msg):
         "threadId": msg.thread_id,
     }
 
+async def aggregate_thread(thread_id):
+    print(f"aggregate {thread_id}")
+    query = db.Message.filter(thread_id=thread_id)
+
+    # Could do all these in one call?
+    message_count = await query.count()
+    print(f"    count {message_count}")
+    if message_count == 0: return
+
+    first_message = await query.first()
+    last_message = await query.last()
+    print(f"    bounds {first_message} {last_message}")
+
+    return await db.Thread.get(id=thread_id).update(
+        first_message_id=first_message.id,
+        last_message_id=last_message.id,
+        message_count=message_count
+    )
+
 class ChatMixin:
     async def create_chat(self, user_id, name, description, picture, members=[], temporary=False):
         if temporary:
@@ -135,6 +154,12 @@ class ChatMixin:
         new_id = await self.create_chat_thread(thread.chat_id, parent_id=thread_id, name=name or thread.name)
 
         if message_id is not None:
+            # Ensure all forks have the correct information
+            forks = await db.Thread.filter(parent_id=thread_id).all()
+            for fork in forks:
+                await aggregate_thread(fork.id)
+
+            await db.Thread.filter(parent_id=thread_id, first_message_id__gte=message_id).update(parent_id=new_id)
             await db.Message.filter(thread_id=thread_id, id__gte=message_id).update(thread_id=new_id)
 
         # Notify users. what a heavy operation!