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

@@ -3,6 +3,7 @@ import 'dart:convert';
 import 'package:json_annotation/json_annotation.dart';
 
 import '../../log.dart';
+import 'events.dart';
 
 part 'submessage.g.dart';
 
@@ -402,6 +403,17 @@ class Poll {
   final Set<String> _existingOptionTexts = {};
   final Map<OptionKey, PollOption> _options = {};
 
+  void handleSubmessageEvent(SubmessageEvent event) {
+    final PollEventSubmessage? pollEventSubmessage;
+    try {
+      pollEventSubmessage = PollEventSubmessage.fromJson(jsonDecode(event.content) as Map<String, Object?>);
+    } catch (e) {
+      assert(debugLog('Malformed submessage event data for poll: $e\n${jsonEncode(event)}')); // TODO(log)
+      return;
+    }
+    applyEvent(event.senderId, pollEventSubmessage);
+  }
+
   void applyEvent(int senderId, PollEventSubmessage event) {
     switch (event) {
       case PollNewOptionEventSubmessage():

lib/api/model/submessage.dart

@@ -1,3 +1,5 @@
+import 'dart:convert';
+
 import '../api/model/events.dart';
 import '../api/model/model.dart';
 import '../log.dart';
@@ -302,4 +304,21 @@ class MessageStoreImpl with MessageStore {
       view.notifyListenersIfMessagePresent(event.messageId);
     }
   }
+
+  void handleSubmessageEvent(SubmessageEvent event) {
+    final message = messages[event.messageId];
+    if (message == null) return;
+
+    final poll = message.poll;
+    if (poll == null) {
+      assert(debugLog('Missing poll for submessage event:\n${jsonEncode(event)}')); // TODO(log)
+      return;
+    }
+
+    poll.handleSubmessageEvent(event);
+
+    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

@@ -1,5 +1,6 @@
 import 'package:checks/checks.dart';
 import 'package:zulip/api/model/model.dart';
+import 'package:zulip/api/model/submessage.dart';
 
 extension UserChecks on Subject<User> {
   Subject<int> get userId => has((x) => x.userId, 'userId');
@@ -39,6 +40,7 @@ extension MessageChecks on Subject<Message> {
   Subject<int> get senderId => has((e) => e.senderId, 'senderId');
   Subject<String> get senderRealmStr => has((e) => e.senderRealmStr, 'senderRealmStr');
   Subject<String> get topic => has((e) => e.topic, 'topic');
+  Subject<Poll?> get poll => has((e) => e.poll, 'poll');
   Subject<int> get timestamp => has((e) => e.timestamp, 'timestamp');
   Subject<String> get type => has((e) => e.type, 'type');
   Subject<List<MessageFlag>> get flags => has((e) => e.flags, 'flags');

test/api/model/model_checks.dart

@@ -37,3 +37,13 @@ extension PollVoteEventChecks on Subject<PollVoteEventSubmessage> {
   Subject<String> get key => has((e) => e.key, 'key');
   Subject<PollVoteOp> get op => has((e) => e.op, 'op');
 }
+
+extension PollChecks on Subject<Poll> {
+  Subject<String> get question => has((e) => e.question, 'question');
+  Subject<Iterable<PollOption>> get options => has((e) => e.options, 'options');
+}
+
+extension PollOptionChecks on Subject<PollOption> {
+  Subject<String> get text => has((e) => e.text, 'text');
+  Subject<Set<int>> get voters => has((e) => e.voters, 'voters');
+}

test/api/model/submessage_checks.dart

@@ -114,4 +114,8 @@ void main() {
       'key': PollEventSubmessage.optionKey(senderId: null, idx: 0)
     })).isA<PollVoteEventSubmessage>().op.equals(PollVoteOp.unknown);
   });
+
+  // Parsing polls with PollEventSubmessages are tested in
+  // `test/model/message_test.dart` in the "new message with initial
+  // submessages" and "handleSubmessageEvent" tests.
 }

test/api/model/submessage_test.dart

@@ -1,3 +1,4 @@
+import 'dart:convert';
 import 'dart:math';
 
 import 'package:zulip/api/model/events.dart';
@@ -343,6 +344,7 @@ StreamMessage streamMessage({
   List<Reaction>? reactions,
   int? timestamp,
   List<MessageFlag>? flags,
+  List<Submessage>? submessages,
 }) {
   _checkPositive(id, 'message ID');
   final effectiveStream = stream ?? _stream(streamId: defaultStreamMessageStreamId);
@@ -362,6 +364,7 @@ StreamMessage streamMessage({
     'id': id ?? _nextMessageId(),
     'last_edit_timestamp': lastEditTimestamp,
     'subject': topic ?? 'example topic',
+    'submessages': submessages ?? [],
     'timestamp': timestamp ?? 1678139636,
     'type': 'stream',
   }) as Map<String, dynamic>);
@@ -386,6 +389,7 @@ DmMessage dmMessage({
   int? lastEditTimestamp,
   int? timestamp,
   List<MessageFlag>? flags,
+  List<Submessage>? submessages,
 }) {
   _checkPositive(id, 'message ID');
   assert(!to.any((user) => user.userId == from.userId));
@@ -401,6 +405,7 @@ DmMessage dmMessage({
     'id': id ?? _nextMessageId(),
     'last_edit_timestamp': lastEditTimestamp,
     'subject': '',
+    'submessages': submessages ?? [],
     'timestamp': timestamp ?? 1678139636,
     'type': 'private',
   }) as Map<String, dynamic>);
@@ -414,6 +419,21 @@ PollWidgetData pollWidgetData({
     extraData: PollWidgetExtraData(question: question, options: options));
 }
 
+Submessage submessage({
+  SubmessageType? msgType,
+  required Object? content,
+  int? senderId,
+}) {
+  return Submessage(
+    msgType: msgType ?? SubmessageType.widget,
+    content: jsonEncode(content),
+    senderId: senderId ?? selfUser.userId,
+  );
+}
+
+PollOption pollOption({required String text, required Iterable<int> voters}) =>
+    PollOption(text: text)..voters.addAll(voters);
+
 ////////////////////////////////////////////////////////////////
 // Aggregate data structures.
 //
@@ -627,6 +647,21 @@ UpdateMessageFlagsRemoveEvent updateMessageFlagsRemoveEvent(
     })));
 }
 
+SubmessageEvent submessageEvent(
+  int messageId,
+  int senderId, {
+  required Object? content,
+}) {
+  return SubmessageEvent(
+    id: 0,
+    msgType: SubmessageType.widget,
+    content: jsonEncode(content),
+    messageId: messageId,
+    senderId: senderId,
+    submessageId: 1,
+  );
+}
+
 TypingEvent typingEvent(SendableNarrow narrow, TypingOp op, int senderId) {
   switch (narrow) {
     case TopicNarrow():