views: Remove reaction on unchecking box.

Author: kaustubh-nair

zulipterminal/core.py

@@ -164,6 +164,7 @@ def show_stream_info(self, stream_id: int) -> None:
         show_stream_view = StreamInfoView(self, stream_id)
         self.show_pop_up(show_stream_view)
 
+    # TODO: remove
     def toggle_message_reaction(self, button: Any) -> None:
         self.model.react_to_message(button.message,
                                     button.emoji_name)

zulipterminal/ui_tools/views.py

@@ -1345,7 +1345,8 @@ def __init__(self, controller: Any, title: str, message: Message
         self.controller = controller
         self.message = message
         widgets = [urwid.CheckBox(reaction['emoji_name'], state=True,
-                                  checked_symbol='✓')
+                                  checked_symbol='✓',
+                                  on_state_change=self.remove_reaction)
                    for reaction in message['reactions']
                    if(controller.model.user_has_reacted_to_msg(
                                         reaction['emoji_name'], message,
@@ -1359,6 +1360,16 @@ def keypress(self, size: urwid_Size, key: str) -> str:
             self.controller.show_emoji_picker(self.message)
         return super().keypress(size, key)
 
+    def remove_reaction(self, checkbox: Any, state: bool) -> None:
+        if not state:
+            self.controller.model.react_to_message(self.message,
+                                                   checkbox.get_label())
+            check_boxes = self.contents['body'][0].body
+            check_boxes.remove(checkbox)
+            removed_check_boxes = urwid.ListBox(
+                                    urwid.SimpleFocusListWalker(check_boxes))
+            self.contents['body'] = (removed_check_boxes, None)
+
 
 class EmojiPickerView(PopUpView):
     def __init__(self, controller: Any, title: str, emoji_names: List[str],