event: Handle submessage event for polls.

We could potentially avoid notifying listeners in some cases when
handling submessage event, but it wouldn't be critically necessary.

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

lib/api/model/events.dart

@@ -3,6 +3,7 @@ import 'package:json_annotation/json_annotation.dart';
 import '../../model/algorithms.dart';
 import 'json.dart';
 import 'model.dart';
+import 'submessage.dart';
 
 part 'events.g.dart';
 
@@ -63,6 +64,7 @@ sealed class Event {
           case 'remove': return UpdateMessageFlagsRemoveEvent.fromJson(json);
           default: return UnexpectedEvent.fromJson(json);
         }
+      case 'submessage': return SubmessageEvent.fromJson(json);
       case 'typing': return TypingEvent.fromJson(json);
       case 'reaction': return ReactionEvent.fromJson(json);
       case 'heartbeat': return HeartbeatEvent.fromJson(json);
@@ -876,6 +878,41 @@ class UpdateMessageFlagsMessageDetail {
   Map<String, dynamic> toJson() => _$UpdateMessageFlagsMessageDetailToJson(this);
 }
 
+/// A Zulip event of type `submessage`: https://zulip.com/api/get-events#submessage
+@JsonSerializable(fieldRename: FieldRename.snake)
+class SubmessageEvent extends Event {
+  @override
+  @JsonKey(includeToJson: true)
+  String get type => 'submessage';
+
+  @JsonKey(unknownEnumValue: SubmessageType.unknown)
+  final SubmessageType msgType;
+  /// [SubmessageData] encoded in JSON.
+  // We cannot parse the String into one of the [SubmessageData] classes because
+  // information from other submessages are required. Specifically, we need
+  // the parsed [WidgetData] from the first [Message.submessages] of the
+  // corresponding message.
+  final String content;
+  final int messageId;
+  final int senderId;
+  final int submessageId;
+
+  SubmessageEvent({
+    required super.id,
+    required this.msgType,
+    required this.content,
+    required this.messageId,
+    required this.senderId,
+    required this.submessageId,
+  });
+
+  factory SubmessageEvent.fromJson(Map<String, dynamic> json) =>
+    _$SubmessageEventFromJson(json);
+
+  @override
+  Map<String, dynamic> toJson() => _$SubmessageEventToJson(this);
+}
+
 /// A Zulip event of type `typing`:
 ///   https://zulip.com/api/get-events#typing-start
 ///   https://zulip.com/api/get-events#typing-stop

lib/api/model/events.g.dart

@@ -1,5 +1,8 @@
+import 'dart:convert';
+
 import '../api/model/events.dart';
 import '../api/model/model.dart';
+import '../api/model/submessage.dart';
 import '../log.dart';
 import 'message_list.dart';
 
@@ -302,4 +305,24 @@ class MessageStoreImpl with MessageStore {
       view.notifyListenersIfMessagePresent(event.messageId);
     }
   }
+
+  void handleSubmessageEvent(SubmessageEvent event) {
+    final poll = messages[event.messageId]?.poll;
+    if (poll == null) return;
+    PollEventSubmessage? pollEventSubmessage;
+    try {
+      pollEventSubmessage = PollEventSubmessage.fromJson(jsonDecode(event.content) as Map<String, Object?>);
+    } on TypeError catch (e) {
+      assert(debugLog('Malformed submessage event data for poll: $e\n${jsonEncode(event)}')); // TODO(log)
+      return;
+    }
+    poll.applyEvent(
+      event.senderId,
+      pollEventSubmessage,
+    );
+
+    for (final view in _messageListViews) {
+      view.notifyListenersIfMessagePresent(event.messageId);
+    }
+  }
 }

lib/model/message.dart

@@ -537,6 +537,10 @@ class PerAccountStore extends ChangeNotifier with ChannelStore, MessageStore {
         _messages.handleUpdateMessageFlagsEvent(event);
         unreads.handleUpdateMessageFlagsEvent(event);
 
+      case SubmessageEvent():
+        assert(debugLog("server event: submessage ${event.content}"));
+        _messages.handleSubmessageEvent(event);
+
       case TypingEvent():
         assert(debugLog("server event: typing/${event.op} ${event.messageType}"));
         typingStatus.handleTypingEvent(event);

lib/model/store.dart

@@ -675,6 +675,21 @@ ReactionEvent reactionEvent(Reaction reaction, ReactionOp op, int messageId) {
   );
 }
 
+SubmessageEvent submessageEvent(
+  int messageId,
+  int senderId,
+  {required String content}
+) {
+  return SubmessageEvent(
+    id: 1,
+    msgType: SubmessageType.widget,
+    content: content,
+    messageId: messageId,
+    senderId: senderId,
+    submessageId: 1,
+  );
+}
+
 ////////////////////////////////////////////////////////////////
 // The entire per-account or global state.
 //