model: Handle updating narrows depending on flags for delete_msg event.

This commit extends the previous commit that added rudimentary
support for handling delete_message event, and allows updating the
special narrows such as mentioned/starred that were depending on
message flags. This commit could be considered as a bugfix over the
previous one. It also handles updating the unread count if the
message was earlier unread before being deleted.

Tests added and amended.
Fixes one check-box in zulip#993.

Author: zee-bit

tests/model/test_model.py

@@ -1601,7 +1601,8 @@ def _set_topics_to_old_and_new(event):
             model.controller.update_screen.assert_called_once_with()
 
     @pytest.mark.parametrize(
-        "event, to_vary_in_index",
+        "event, to_vary_in_index, to_vary_in_message, expected_set_count_called,"
+        "expected_star_count_called",
         [
             case(
                 {
@@ -1614,7 +1615,58 @@ def _set_topics_to_old_and_new(event):
                     "all_msg_ids": {537286, 537287, 537288},
                     "topic_msg_ids": {205: {"Test": {537286}}},
                 },
-                id="stream_msg_deleted_from_all_msg",
+                {537286: {"flags": ["read"]}},
+                False,
+                False,
+                id="read_stream_msg_deleted_from_all_msg",
+            ),
+            case(
+                {
+                    "message_id": 537286,
+                    "message_type": "stream",
+                    "stream_id": 205,
+                    "topic": "Test",
+                },
+                {
+                    "mentioned_msg_ids": {537286},
+                    "topic_msg_ids": {205: {"Test": {537286}}},
+                },
+                {537286: {"flags": ["read", "mentioned"]}},
+                False,
+                False,
+                id="read+mentioned_stream_msg_deleted_from_mentions",
+            ),
+            case(
+                {
+                    "message_id": 537286,
+                    "message_type": "stream",
+                    "stream_id": 205,
+                    "topic": "Test",
+                },
+                {
+                    "starred_msg_ids": {537286},
+                    "topic_msg_ids": {205: {"Test": {537286}}},
+                },
+                {537286: {"flags": ["read", "starred"]}},
+                False,
+                True,
+                id="read+starred_stream_msg_deleted_from_starred",
+            ),
+            case(
+                {
+                    "message_id": 537286,
+                    "message_type": "stream",
+                    "stream_id": 205,
+                    "topic": "Test",
+                },
+                {
+                    "mentioned_msg_ids": {537286},
+                    "topic_msg_ids": {205: {"Test": {537286}}},
+                },
+                {537286: {"flags": ["wildcard_mentioned"]}},
+                True,
+                False,
+                id="unread+wildcard_mentioned_stream_msg_deleted_from_mentioned",
             ),
             case(
                 {
@@ -1626,7 +1678,26 @@ def _set_topics_to_old_and_new(event):
                     "private_msg_ids": {537287},
                     "private_msg_ids_by_user_ids": {(5140, 5179): {537287}},
                 },
-                id="rivate_msg_deleted_from_private_msgs",
+                {537287: {"flags": []}},
+                True,
+                False,
+                id="unread_private_msg_deleted_from_private_msgs",
+            ),
+            case(
+                {
+                    "message_id": 537287,
+                    "message_type": "private",
+                    "sender_id": 5140,
+                },
+                {
+                    "private_msg_ids": {537287, 537288},
+                    "starred_msg_ids": {537287},
+                    "private_msg_ids_by_user_ids": {(5140, 5179): {537287}},
+                },
+                {537287: {"flags": ["read", "starred"]}},
+                False,
+                True,
+                id="starred_private_msg_deleted_from_starred+private_msgs",
             ),
             case(
                 {
@@ -1641,7 +1712,10 @@ def _set_topics_to_old_and_new(event):
                         (5179, 5140, 5180): {537288},
                     },
                 },
-                id="group_msg_deleted_from_private_msgs",
+                {537288: {"flags": ["read", "wildcard_mentioned"]}},
+                False,
+                False,
+                id="read+wildcard_mentioned_group_msg_deleted_from_private_msgs",
             ),
         ],
     )
@@ -1652,23 +1726,35 @@ def test__handle_delete_message_event(
         empty_index,
         event,
         to_vary_in_index,
+        to_vary_in_message,
+        expected_set_count_called,
+        expected_star_count_called,
     ):
         event["type"] = "delete_message"
         message_id = event["message_id"]
 
         model.index = empty_index
         model.index.update(to_vary_in_index)
+        model.index["messages"].update(to_vary_in_message)
 
         mocker.patch(MODEL + "._update_rendered_view")
+        set_count = mocker.patch("zulipterminal.model.set_count")
         self.controller.view.message_view = mocker.Mock(log=[])
 
         assert message_id in model.index["messages"].keys()
 
         model._handle_delete_message_event(event)
 
+        if expected_set_count_called:
+            set_count.assert_called_once_with([message_id], self.controller, -1)
+        if expected_star_count_called:
+            self.controller.view.starred_button.update_count.assert_called
+
         assert message_id not in model.index["messages"]
         assert message_id not in model.index["all_msg_ids"]
         assert message_id not in model.index["edited_messages"]
+        assert message_id not in model.index["mentioned_msg_ids"]
+        assert message_id not in model.index["starred_msg_ids"]
         if event["message_type"] == "private":
             assert message_id not in model.index["private_msg_ids"]
             assert message_id not in model.index["private_msg_ids_by_user_ids"].values()

zulipterminal/model.py

@@ -1172,13 +1172,26 @@ def _handle_delete_message_event(self, event: Event) -> None:
         indexed_message = self.index["messages"].get(message_id, None)
 
         if indexed_message:
+            # Update unread_count if message was unread before being deleted
+            # We need to do this before removing the message from index.
+            if "read" not in indexed_message["flags"]:
+                set_count([message_id], self.controller, -1)
+            # Update starred_count if message was starred before being deleted
+            if "starred" in indexed_message["flags"]:
+                self.index["starred_msg_ids"].discard(message_id)
+                self.controller.view.starred_button.update_count(
+                    self.controller.view.starred_button.count - 1
+                )
+
             # Remove all traces of the message from index if present and
             # update the rendered view.
             # FIXME?: Do we need to archive the message instead of completely
             # erasing from index?
             self.index["messages"].pop(message_id, None)
             self.index["all_msg_ids"].discard(message_id)
             self.index["edited_messages"].discard(message_id)
+            if {"mentioned", "wildcard_mentioned"} & set(indexed_message["flags"]):
+                self.index["mentioned_msg_ids"].discard(message_id)
 
             if event["message_type"] == "private":
                 self.index["private_msg_ids"].discard(message_id)