realtime(chats): update subscriptions on delete/leave chat actions

app/chats/router.py

@@ -19,6 +19,8 @@ from app.chats.schemas import (
     ChatRead,
     ChatTitleUpdateRequest,
 )
+from app.chats import repository as chats_repository
+from app.chats.models import ChatType
 from app.chats.service import (
     add_chat_member_for_user,
     ban_chat_member_for_user,
@@ -250,7 +252,19 @@ async def delete_chat(
     db: AsyncSession = Depends(get_db),
     current_user: User = Depends(get_current_user),
 ) -> None:
+    chat_before_delete = await chats_repository.get_chat_by_id(db, chat_id)
+    delete_for_all = bool(
+        chat_before_delete
+        and (
+            (for_all and not chat_before_delete.is_saved)
+            or (chat_before_delete.type == ChatType.CHANNEL and not chat_before_delete.is_saved)
+        )
+    )
     await delete_chat_for_user(db, chat_id=chat_id, user_id=current_user.id, payload=ChatDeleteRequest(for_all=for_all))
+    if chat_before_delete and not chat_before_delete.is_saved:
+        realtime_gateway.remove_chat_subscription(chat_id=chat_id, user_id=current_user.id)
+        if not delete_for_all:
+            await realtime_gateway.publish_chat_updated(chat_id=chat_id)
 
 
 @router.post("/{chat_id}/clear", status_code=status.HTTP_204_NO_CONTENT)