boxes/messages: Disable recpient editing when editing a private message.

In order to fully disable editing (not only cycling to it, but e.g.
prevent editing through mouse clicks) we need to make the editing
of a message a different UI box than the usual reply.

This new box uses a urwid.Text to display the recipient information
rather than providing an editable field.

Fixes zulip#774.

Co-authored-by: zormit <[email protected]>

zulipterminal/ui_tools/boxes.py

@@ -222,6 +222,15 @@ def update_recipients_from_user_ids(
             self.recipient_emails = []
             return ""
 
+    def private_box_edit_view(
+        self,
+        *,
+        recipient_user_ids: Optional[List[int]] = None,
+    ) -> None:
+        self.recipient_info = self.update_recipients_from_user_ids(recipient_user_ids)
+        self.to_write_box = urwid.Text("To: " + self.recipient_info)
+        self._setup_common_private_compose()
+
     def private_box_view(
         self,
         *,

zulipterminal/ui_tools/messages.py

@@ -1096,7 +1096,9 @@ def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
                     )
 
             if self.message["type"] == "private":
-                self.keypress(size, primary_key_for_command("REPLY_MESSAGE"))
+                self.model.controller.view.write_box.private_box_edit_view(
+                    recipient_user_ids=self.recipient_ids,
+                )
             elif self.message["type"] == "stream":
                 self.model.controller.view.write_box.stream_box_edit_view(
                     stream_id=self.stream_id,