api: Add user_status event

Co-authored-by: Chris Bobbe <[email protected]>

Author: sm-sayedi

lib/api/model/events.dart

@@ -69,6 +69,7 @@ sealed class Event {
           default: return UnexpectedEvent.fromJson(json);
         }
       // case 'muted_topics': … // TODO(#422) we ignore this feature on older servers
+      case 'user_status': return UserStatusEvent.fromJson(json);
       case 'user_topic': return UserTopicEvent.fromJson(json);
       case 'muted_users': return MutedUsersEvent.fromJson(json);
       case 'message': return MessageEvent.fromJson(json);
@@ -797,6 +798,41 @@ class SubscriptionPeerRemoveEvent extends SubscriptionEvent {
   Map<String, dynamic> toJson() => _$SubscriptionPeerRemoveEventToJson(this);
 }
 
+/// A Zulip event of type `user_status`: https://zulip.com/api/get-events#user_status
+@JsonSerializable(fieldRename: FieldRename.snake, createToJson: false)
+class UserStatusEvent extends Event {
+  @override
+  @JsonKey(includeToJson: true)
+  String get type => 'user_status';
+
+  final int userId;
+
+  @JsonKey(readValue: _readChange)
+  final UserStatusChange change;
+
+  static Object? _readChange(Map<dynamic, dynamic> json, String key) {
+    assert(json is Map<String, dynamic>); // value came through `fromJson` with this type
+    return json;
+  }
+
+  UserStatusEvent({
+    required super.id,
+    required this.userId,
+    required this.change,
+  });
+
+  factory UserStatusEvent.fromJson(Map<String, dynamic> json) =>
+    _$UserStatusEventFromJson(json);
+
+  @override
+  Map<String, dynamic> toJson() => {
+    'id': id,
+    'type': type,
+    'user_id': userId,
+    ...change.toJson(),
+  };
+}
+
 /// A Zulip event of type `user_topic`: https://zulip.com/api/get-events#user_topic
 @JsonSerializable(fieldRename: FieldRename.snake)
 class UserTopicEvent extends Event {

lib/api/model/events.g.dart

@@ -959,6 +959,10 @@ class PerAccountStore extends PerAccountStoreBase with
         _channels.handleSubscriptionEvent(event);
         notifyListeners();
 
+      case UserStatusEvent():
+        // TODO: handle
+        break;
+
       case UserTopicEvent():
         assert(debugLog("server event: user_topic"));
         _messages.handleUserTopicEvent(event);