boxes/model: Maintain stream_id in WriteBox for stream box view.

The stream id is useful for referring to a specific stream in a way that
is independent of its name, which can vary over time.

The stream_id needs to be synchronized in case a user manually modifies
the stream name in the recipient box.

This will be important for implementing message drafts and
autocompleting topics.

A new helper method is added to Model to fetch stream_id using its name.

Author: kaustubh-nair

zulipterminal/model.py

@@ -642,6 +642,12 @@ def toggle_stream_muted_status(self, stream_id: int) -> bool:
         display_error_if_present(response, self.controller)
         return response['result'] == 'success'
 
+    def stream_id_from_name(self, stream_name: str) -> int:
+        for stream_id, stream in self.stream_dict.items():
+            if stream['name'] == stream_name:
+                return stream_id
+        raise RuntimeError("Invalid stream name.")
+
     def is_pinned_stream(self, stream_id: int) -> bool:
         return stream_id in list(stream[1] for stream in self.pinned_streams)
 

zulipterminal/ui_tools/boxes.py

@@ -33,6 +33,7 @@ def __init__(self, view: Any) -> None:
         self.view = view
         self.msg_edit_id = None  # type: Optional[int]
         self.is_in_typeahead_mode = False
+        self.stream_id = None  # type: Optional[int]
         self.recipient_user_ids = []  # type: List[int]
 
     def main_view(self, new: bool) -> Any:
@@ -72,6 +73,7 @@ def private_box_view(self, button: Any=None, email: str='',
     def stream_box_view(self, stream_id: int, caption: str='', title: str='',
                         ) -> None:
         self.set_editor_mode()
+        self.stream_id = stream_id
         self.recipient_user_ids = self.model.get_other_subscribers_in_stream(
                                             stream_id=stream_id)
         self.to_write_box = None
@@ -271,6 +273,8 @@ def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
                         user_ids = self.model.get_other_subscribers_in_stream(
                                                     stream_name=stream_name)
                         self.recipient_user_ids = user_ids
+                        self.stream_id = self.model.stream_id_by_name(
+                                                                stream_name)
 
                         header.focus_col = 1
                         return key