model/api_types: Create method in model to handle stream unsubscription.

This commit adds a function named "_unsubscribe_from_streams" to
model.py. This function updates subscription data by removing
unsubscribed streams from class variables - pinned_streams,
unpinned_streams, muted_streams, and visual_notified_streams.

Co-authored-by: Abhirup Pal <abhiruppalmethodist@gmail.com>
Co-authored-by: Vishwesh Pillai <vishwesh103@gmail.com>

Author: theViz343

zulipterminal/api_types.py

@@ -415,6 +415,11 @@ class RealmUserEvent(TypedDict):
 # (also -peer_add and -peer_remove; FIXME: -add & -remove are not yet supported)
 
 
+class RemovedSubscription(TypedDict):
+    stream_id: int
+    name: str
+
+
 # Update of personal properties
 class SubscriptionUpdateEvent(SubscriptionSettingChange):
     type: Literal["subscription"]

zulipterminal/model.py

@@ -44,6 +44,7 @@
     RealmEmojiData,
     RealmUser,
     Stream,
+    RemovedSubscription,
     StreamComposition,
     StreamMessageUpdateRequest,
     Subscription,
@@ -1277,7 +1278,13 @@ def make_reduced_stream_data(stream: Subscription) -> StreamData:
             # different formats
             subscription["color"] = canonicalize_color(subscription["color"])
 
-            self._subscribed_streams[subscription["stream_id"]] = subscription
+            stream_id = subscription["stream_id"]
+            if stream_id in self.unsubscribed_stream_dict:
+                del self.unsubscribed_stream_dict[stream_id]
+            elif stream_id in self.never_subscribed_stream_dict:
+                del self.never_subscribed_stream_dict[stream_id]
+            self._subscribed_streams[stream_id] = subscription
+
             stream_data = make_reduced_stream_data(subscription)
             if subscription["pin_to_top"]:
                 new_pinned_streams.append(stream_data)
@@ -1300,6 +1307,29 @@ def make_reduced_stream_data(stream: Subscription) -> StreamData:
             new_visual_notified_streams
         )
 
+    def _unsubscribe_from_streams(
+        self, subscriptions: List[RemovedSubscription]
+    ) -> None:
+        for subscription in subscriptions:
+            stream_id = subscription["stream_id"]
+            self.pinned_streams[:] = [
+                stream
+                for stream in self.pinned_streams
+                if stream.get("id") != stream_id
+            ]
+            self.unpinned_streams[:] = [
+                stream
+                for stream in self.unpinned_streams
+                if stream.get("id") != stream_id
+            ]
+            if stream_id in self.muted_streams:
+                self.muted_streams.remove(stream_id)
+            if stream_id in self.visual_notified_streams:
+                self.visual_notified_streams.remove(stream_id)
+            if stream_id in self.stream_dict:
+                self.unsubscribed_stream_dict[stream_id] = self.stream_dict[stream_id]
+                del self.stream_dict[stream_id]
+
     def _group_info_from_realm_user_groups(
         self, groups: List[Dict[str, Any]]
     ) -> List[str]: