Fix slack messages for todo updates and addition (#765)

* Fix slack messages for todo updates and addition

* Fix linting

* Zip new old todos instead of indexing old todos

Co-authored-by: Aditya Bharadwaj <aditya@b12.io>

orchestra/todos/views.py

@@ -1,4 +1,5 @@
 import logging
+import copy
 
 from django.contrib import messages
 from django.contrib.admin.views.decorators import staff_member_required
@@ -12,6 +13,7 @@
 from rest_framework.response import Response
 from rest_framework.decorators import action
 from jsonview.exceptions import BadRequest
+from django.db.models.query import QuerySet
 
 from orchestra.core.errors import TodoListTemplateValidationError
 from orchestra.models import Task
@@ -178,16 +180,22 @@ def patch(self, request, *args, **kwargs):
         return self.put(request, *args, **kwargs)
 
     def perform_update(self, serializer):
-        todo = serializer.save()
-        if isinstance(todo, Todo):
-            old_todo = self.get_object()
-            notify_single_todo_update(
-                self.request.user, old_todo, todo)
+        old_data = copy.deepcopy(serializer.instance)
+        old_todos = list(old_data) if isinstance(
+            old_data, QuerySet) else [old_data]
+        data = serializer.save()
+        todos = data if isinstance(data, list) else [data]
+        for old_todo, new_todo in zip(old_todos, todos):
+            if isinstance(new_todo, Todo):
+                notify_single_todo_update(
+                    self.request.user, old_todo, new_todo)
 
     def perform_create(self, serializer):
-        todo = serializer.save()
-        if isinstance(todo, Todo):
-            notify_todo_created(todo, self.request.user)
+        data = serializer.save()
+        todos = data if isinstance(data, list) else [data]
+        for todo in todos:
+            if isinstance(todo, Todo):
+                notify_todo_created(todo, self.request.user)
 
 
 class TodoViewset(GenericTodoViewset):