model: Update index['unread_msgs'] when marking msg read/unread.

Add message to data structure when new message recieved, and remove when
marking it as read.

Author: kaustubh-nair

tests/model/test_model.py

@@ -1248,7 +1248,9 @@ def test_update_read_status(self, mocker, model, event_op,
                                 event_message_ids, indexed_ids,
                                 flags_before, flags_after):
         model.index = dict(messages={msg_id: {'flags': flags_before}
-                                     for msg_id in indexed_ids})
+                                     for msg_id in indexed_ids},
+                           unread_msgs={msg_id: {}
+                                        for msg_id in event_message_ids})
         event = {
             'messages': event_message_ids,
             'type': 'update_message_flags',
@@ -1279,6 +1281,7 @@ def test_update_read_status(self, mocker, model, event_op,
         if event_op == 'add':
             set_count.assert_called_once_with(list(changed_ids),
                                               self.controller, -1)
+            assert len(model.index['unread_msgs']) == 0
         elif event_op == 'remove':
             set_count.assert_not_called()
 

zulipterminal/model.py

@@ -731,6 +731,10 @@ def append_message(self, event: Event) -> None:
                 recipient_stream = response['display_recipient']
                 narrow_stream = self.narrow[0][1]
                 append_to_stream = recipient_stream == narrow_stream
+                unread_data = {'type': response['type'],
+                               'sender_id': response['sender_id'],
+                               'subject': response['subject'],
+                               'display_recipient': recipient_stream}
 
                 if append_to_stream and (len(self.narrow) == 1 or
                                          (len(self.narrow) == 2 and
@@ -745,7 +749,10 @@ def append_message(self, event: Event) -> None:
                     [user['id'] for user in response['display_recipient']])
                 if narrow_recipients == message_recipients:
                     self.msg_list.log.append(msg_w)
+                unread_data = {'type': response['type'],
+                               'display_recipient': message_recipients}
             if 'read' not in response['flags']:
+                self.index['unread_msgs'].update({response['id']: unread_data})
                 set_count([response['id']], self.controller, 1)
             self.controller.update_screen()
 
@@ -840,8 +847,10 @@ def update_message_flag_status(self, event: Event) -> None:
             self.update_rendered_view(message_id)
 
         if event['operation'] == 'add' and flag_to_change == 'read':
-            set_count(list(message_ids_to_mark & indexed_message_ids),
+            set_count(list(message_ids_to_mark),
                       self.controller, -1)
+            for key in message_ids_to_mark:
+                self.index['unread_msgs'].pop(key)
 
     def update_rendered_view(self, msg_id: int) -> None:
         # Update new content in the rendered view