Add Reaction class; uncomment Message.reactions and update on events

lib/api/model/events.dart

@@ -33,6 +33,7 @@ sealed class Event {
       case 'message': return MessageEvent.fromJson(json);
       case 'update_message': return UpdateMessageEvent.fromJson(json);
       case 'delete_message': return DeleteMessageEvent.fromJson(json);
+      case 'reaction': return ReactionEvent.fromJson(json);
       case 'heartbeat': return HeartbeatEvent.fromJson(json);
       // TODO add many more event types
       default: return UnexpectedEvent.fromJson(json);
@@ -370,6 +371,50 @@ enum MessageType {
   private;
 }
 
+/// A Zulip event of type `reaction`, with op `add` or `remove`.
+///
+/// See:
+///   https://zulip.com/api/get-events#reaction-add
+///   https://zulip.com/api/get-events#reaction-remove
+@JsonSerializable(fieldRename: FieldRename.snake)
+class ReactionEvent extends Event {
+  @override
+  @JsonKey(includeToJson: true)
+  String get type => 'reaction';
+
+  final ReactionOp op;
+
+  final String emojiName;
+  final String emojiCode;
+  final ReactionType reactionType;
+  final int userId;
+  // final Map<String, dynamic> user; // deprecated; ignore
+  final int messageId;
+
+  ReactionEvent({
+    required super.id,
+    required this.op,
+    required this.emojiName,
+    required this.emojiCode,
+    required this.reactionType,
+    required this.userId,
+    required this.messageId,
+  });
+
+  factory ReactionEvent.fromJson(Map<String, dynamic> json) =>
+    _$ReactionEventFromJson(json);
+
+  @override
+  Map<String, dynamic> toJson() => _$ReactionEventToJson(this);
+}
+
+/// The type of [ReactionEvent.op].
+@JsonEnum(fieldRename: FieldRename.snake)
+enum ReactionOp {
+  add,
+  remove,
+}
+
 /// A Zulip event of type `heartbeat`: https://zulip.com/api/get-events#heartbeat
 @JsonSerializable(fieldRename: FieldRename.snake)
 class HeartbeatEvent extends Event {

lib/api/model/model.dart

@@ -258,7 +258,7 @@ sealed class Message {
   bool isMeMessage;
   int? lastEditTimestamp;
 
-  // final List<Reaction> reactions; // TODO handle
+  final List<Reaction> reactions;
   final int recipientId;
   final String senderEmail;
   final String senderFullName;
@@ -282,6 +282,7 @@ sealed class Message {
     required this.id,
     required this.isMeMessage,
     this.lastEditTimestamp,
+    required this.reactions,
     required this.recipientId,
     required this.senderEmail,
     required this.senderFullName,
@@ -320,6 +321,7 @@ class StreamMessage extends Message {
     required super.id,
     required super.isMeMessage,
     super.lastEditTimestamp,
+    required super.reactions,
     required super.recipientId,
     required super.senderEmail,
     required super.senderFullName,
@@ -421,6 +423,7 @@ class DmMessage extends Message {
     required super.id,
     required super.isMeMessage,
     super.lastEditTimestamp,
+    required super.reactions,
     required super.recipientId,
     required super.senderEmail,
     required super.senderFullName,
@@ -440,3 +443,36 @@ class DmMessage extends Message {
   @override
   Map<String, dynamic> toJson() => _$DmMessageToJson(this);
 }
+
+/// As in [Message.reactions].
+@JsonSerializable(fieldRename: FieldRename.snake)
+class Reaction {
+  final String emojiName;
+  final String emojiCode;
+  final ReactionType reactionType;
+  final int userId;
+  // final Map<String, dynamic> user; // deprecated; ignore
+
+  Reaction({
+    required this.emojiName,
+    required this.emojiCode,
+    required this.reactionType,
+    required this.userId,
+  });
+
+  factory Reaction.fromJson(Map<String, dynamic> json) =>
+    _$ReactionFromJson(json);
+
+  Map<String, dynamic> toJson() => _$ReactionToJson(this);
+
+  @override
+  String toString() => 'Reaction(emojiName: $emojiName, emojiCode: $emojiCode, reactionType: $reactionType, userId: $userId)';
+}
+
+/// As in [Reaction.reactionType].
+@JsonEnum(fieldRename: FieldRename.snake)
+enum ReactionType {
+  unicodeEmoji,
+  realmEmoji,
+  zulipExtraEmoji;
+}

lib/model/message_list.dart

@@ -151,6 +151,32 @@ class MessageListView extends ChangeNotifier {
     notifyListeners();
   }
 
+  void maybeUpdateMessageReactions(ReactionEvent event) {
+    final index = findMessageWithId(event.messageId);
+    if (index == -1) {
+      return;
+    }
+
+    final message = messages[index];
+    switch (event.op) {
+      case ReactionOp.add:
+        message.reactions.add(Reaction(
+          emojiName: event.emojiName,
+          emojiCode: event.emojiCode,
+          reactionType: event.reactionType,
+          userId: event.userId,
+        ));
+      case ReactionOp.remove:
+        message.reactions.removeWhere((r) {
+          return r.emojiCode == event.emojiCode
+            && r.reactionType == event.reactionType
+            && r.userId == event.userId;
+        });
+    }
+
+    notifyListeners();
+  }
+
   /// Called when the app is reassembled during debugging, e.g. for hot reload.
   ///
   /// This will redo from scratch any computations we can, such as parsing

lib/model/store.dart

@@ -278,6 +278,11 @@ class PerAccountStore extends ChangeNotifier {
     } else if (event is DeleteMessageEvent) {
       assert(debugLog("server event: delete_message ${event.messageIds}"));
       // TODO handle
+    } else if (event is ReactionEvent) {
+      assert(debugLog("server event: reaction/${event.op}"));
+      for (final view in _messageListViews) {
+        view.maybeUpdateMessageReactions(event);
+      }
     } else if (event is UnexpectedEvent) {
       assert(debugLog("server event: ${jsonEncode(event.toJson())}")); // TODO log better
     } else {

test/api/model/model_checks.dart

@@ -5,15 +5,43 @@ extension MessageChecks on Subject<Message> {
   Subject<Map<String, dynamic>> get toJson => has((e) => e.toJson(), 'toJson');
 
   void jsonEquals(Message expected) {
-    toJson.deepEquals(expected.toJson());
+    final expectedJson = expected.toJson();
+    expectedJson['reactions'] = it()..isA<List<Reaction>>().jsonEquals(expected.reactions);
+    toJson.deepEquals(expectedJson);
   }
 
   Subject<String> get content => has((e) => e.content, 'content');
   Subject<bool> get isMeMessage => has((e) => e.isMeMessage, 'isMeMessage');
   Subject<int?> get lastEditTimestamp => has((e) => e.lastEditTimestamp, 'lastEditTimestamp');
+  Subject<List<Reaction>> get reactions => has((e) => e.reactions, 'reactions');
   Subject<List<String>> get flags => has((e) => e.flags, 'flags');
 
   // TODO accessors for other fields
 }
 
+extension ReactionsChecks on Subject<List<Reaction>> {
+  void deepEquals(_) {
+    throw UnimplementedError('Tried to call [Subject<List<Reaction>>.deepEquals]. Use jsonEquals instead.');
+  }
+
+  void jsonEquals(List<Reaction> expected) {
+    // (cast, to bypass this extension's deepEquals implementation, which throws)
+    // ignore: unnecessary_cast
+    (this as Subject<List>).deepEquals(expected.map((r) => it()..isA<Reaction>().jsonEquals(r)));
+  }
+}
+
+extension ReactionChecks on Subject<Reaction> {
+  Subject<Map<String, dynamic>> get toJson => has((r) => r.toJson(), 'toJson');
+
+  void jsonEquals(Reaction expected) {
+    toJson.deepEquals(expected.toJson());
+  }
+
+  Subject<String> get emojiName => has((r) => r.emojiName, 'emojiName');
+  Subject<String> get emojiCode => has((r) => r.emojiCode, 'emojiCode');
+  Subject<ReactionType> get reactionType => has((r) => r.reactionType, 'reactionType');
+  Subject<int> get userId => has((r) => r.userId, 'userId');
+}
+
 // TODO similar extensions for other types in model

test/example_data.dart

@@ -132,6 +132,7 @@ StreamMessage streamMessage({
   String? content,
   String? contentMarkdown,
   int? lastEditTimestamp,
+  List<Reaction>? reactions,
   List<String>? flags,
 }) {
   final effectiveStream = stream ?? _stream();
@@ -146,6 +147,7 @@ StreamMessage streamMessage({
     ..._messagePropertiesFromContent(content, contentMarkdown),
     'display_recipient': effectiveStream.name,
     'stream_id': effectiveStream.streamId,
+    'reactions': reactions?.map((r) => r.toJson()).toList() ?? [],
     'flags': flags ?? [],
     'id': id ?? 1234567, // TODO generate example IDs
     'last_edit_timestamp': lastEditTimestamp,
@@ -176,7 +178,7 @@ DmMessage dmMessage({
     'display_recipient': [from, ...to]
       .map((u) => {'id': u.userId, 'email': u.email, 'full_name': u.fullName})
       .toList(growable: false),
-
+    'reactions': [],
     'flags': flags ?? [],
     'id': id ?? 1234567, // TODO generate example IDs
     'last_edit_timestamp': lastEditTimestamp,
@@ -186,6 +188,13 @@ DmMessage dmMessage({
   });
 }
 
+Reaction unicodeEmojiReaction = Reaction(
+  emojiName: 'thumbs_up',
+  emojiCode: '1f44d',
+  reactionType: ReactionType.unicodeEmoji,
+  userId: selfUser.userId,
+);
+
 // TODO example data for many more types
 
 InitialSnapshot initialSnapshot({