Support general chat

lib/api/model/initial_snapshot.dart

@@ -80,6 +80,8 @@ class InitialSnapshot {
 
   final Uri? serverEmojiDataUrl; // TODO(server-6)
 
+  final String? realmEmptyTopicDisplayName; // TODO(server-10)
+
   @JsonKey(readValue: _readUsersIsActiveFallbackTrue)
   final List<User> realmUsers;
   @JsonKey(readValue: _readUsersIsActiveFallbackFalse)
@@ -132,6 +134,7 @@ class InitialSnapshot {
     required this.realmDefaultExternalAccounts,
     required this.maxFileUploadSizeMib,
     required this.serverEmojiDataUrl,
+    required this.realmEmptyTopicDisplayName,
     required this.realmUsers,
     required this.realmNonActiveUsers,
     required this.crossRealmBots,

lib/api/model/model.dart

@@ -690,7 +690,7 @@ extension type const TopicName(String _value) {
   /// so that UI code can identify when it needs to represent the topic
   /// specially in the way prescribed for "general chat".
   // TODO(#1250) carry out that plan
-  String get displayName => _value;
+  String? get displayName => _value.isEmpty ? null : _value;
 
   /// The key to use for "same topic as" comparisons.
   String canonicalize() => apiName.toLowerCase();

lib/api/route/channels.dart

@@ -8,7 +8,10 @@ part 'channels.g.dart';
 Future<GetStreamTopicsResult> getStreamTopics(ApiConnection connection, {
   required int streamId,
 }) {
-  return connection.get('getStreamTopics', GetStreamTopicsResult.fromJson, 'users/me/$streamId/topics', {});
+  final supportsEmptyTopics = connection.zulipFeatureLevel! >= 334; // TODO(server-10)
+  return connection.get('getStreamTopics', GetStreamTopicsResult.fromJson, 'users/me/$streamId/topics', {
+    if (supportsEmptyTopics) 'allow_empty_topic_name': true,
+  });
 }
 
 @JsonSerializable(fieldRename: FieldRename.snake)

lib/api/route/events.dart

@@ -18,6 +18,7 @@ Future<InitialSnapshot> registerQueue(ApiConnection connection) {
       'user_avatar_url_field_optional': false, // TODO(#254): turn on
       'stream_typing_notifications': true,
       'user_settings_object': true,
+      'empty_topic_name': true,
     },
   });
 }

lib/api/route/messages.dart

@@ -59,8 +59,10 @@ Future<GetMessageResult> getMessage(ApiConnection connection, {
   bool? applyMarkdown,
 }) {
   assert(connection.zulipFeatureLevel! >= 120);
+  final supportsEmptyTopics = connection.zulipFeatureLevel! >= 334; // TODO(server-10)
   return connection.get('getMessage', GetMessageResult.fromJson, 'messages/$messageId', {
     if (applyMarkdown != null) 'apply_markdown': applyMarkdown,
+    if (supportsEmptyTopics) 'allow_empty_topic_name': true,
   });
 }
 
@@ -90,6 +92,7 @@ Future<GetMessagesResult> getMessages(ApiConnection connection, {
   bool? applyMarkdown,
   // bool? useFirstUnreadAnchor // omitted because deprecated
 }) {
+  final supportsEmptyTopics = connection.zulipFeatureLevel! >= 334; // TODO(server-10)
   return connection.get('getMessages', GetMessagesResult.fromJson, 'messages', {
     'narrow': resolveDmElements(narrow, connection.zulipFeatureLevel!),
     'anchor': RawParameter(anchor.toJson()),
@@ -98,6 +101,7 @@ Future<GetMessagesResult> getMessages(ApiConnection connection, {
     'num_after': numAfter,
     if (clientGravatar != null) 'client_gravatar': clientGravatar,
     if (applyMarkdown != null) 'apply_markdown': applyMarkdown,
+    if (supportsEmptyTopics) 'allow_empty_topic_name': true,
   });
 }
 

lib/model/autocomplete.dart

@@ -844,7 +844,7 @@ class TopicAutocompleteView extends AutocompleteView<TopicAutocompleteQuery, Top
   }
 
   TopicAutocompleteResult? _testTopic(TopicAutocompleteQuery query, TopicName topic) {
-    if (query.testTopic(topic)) {
+    if (query.testTopic(store, topic)) {
       return TopicAutocompleteResult(topic: topic);
     }
     return null;
@@ -862,10 +862,15 @@ class TopicAutocompleteView extends AutocompleteView<TopicAutocompleteQuery, Top
 class TopicAutocompleteQuery extends AutocompleteQuery {
   TopicAutocompleteQuery(super.raw);
 
-  bool testTopic(TopicName topic) {
+  bool testTopic(PerAccountStore store, TopicName topic) {
     // TODO(#881): Sort by match relevance, like web does.
+
+    if (topic.displayName == null) {
+      return store.realmEmptyTopicDisplayName.toLowerCase()
+        .contains(raw.toLowerCase());
+    }
     return topic.displayName != raw
-      && topic.displayName.toLowerCase().contains(raw.toLowerCase());
+      && topic.displayName!.toLowerCase().contains(raw.toLowerCase());
   }
 
   @override

lib/model/store.dart

@@ -271,6 +271,7 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, ChannelStore, Mess
       realmMandatoryTopics: initialSnapshot.realmMandatoryTopics,
       realmWaitingPeriodThreshold: initialSnapshot.realmWaitingPeriodThreshold,
       maxFileUploadSizeMib: initialSnapshot.maxFileUploadSizeMib,
+      realmEmptyTopicDisplayName: initialSnapshot.realmEmptyTopicDisplayName,
       realmDefaultExternalAccounts: initialSnapshot.realmDefaultExternalAccounts,
       customProfileFields: _sortCustomProfileFields(initialSnapshot.customProfileFields),
       emailAddressVisibility: initialSnapshot.emailAddressVisibility,
@@ -315,6 +316,7 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, ChannelStore, Mess
     required this.realmMandatoryTopics,
     required this.realmWaitingPeriodThreshold,
     required this.maxFileUploadSizeMib,
+    required String? realmEmptyTopicDisplayName,
     required this.realmDefaultExternalAccounts,
     required this.customProfileFields,
     required this.emailAddressVisibility,
@@ -335,6 +337,7 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, ChannelStore, Mess
        assert(realmUrl == connection.realmUrl),
        assert(emoji.realmUrl == realmUrl),
        _globalStore = globalStore,
+       _realmEmptyTopicDisplayName = realmEmptyTopicDisplayName,
        _emoji = emoji,
        _channels = channels,
        _messages = messages;
@@ -381,6 +384,11 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, ChannelStore, Mess
   /// For docs, please see [InitialSnapshot.realmWaitingPeriodThreshold].
   final int realmWaitingPeriodThreshold;  // TODO(#668): update this realm setting
   final int maxFileUploadSizeMib; // No event for this.
+  final String? _realmEmptyTopicDisplayName; // TODO(#668): update this realm setting
+  String get realmEmptyTopicDisplayName {
+    assert(_realmEmptyTopicDisplayName != null); // TODO(log)
+    return _realmEmptyTopicDisplayName ?? 'general chat';
+  }
   final Map<String, RealmDefaultExternalAccount> realmDefaultExternalAccounts;
   List<CustomProfileField> customProfileFields;
   /// For docs, please see [InitialSnapshot.emailAddressVisibility].

lib/widgets/autocomplete.dart

@@ -328,12 +328,21 @@ class TopicAutocomplete extends AutocompleteField<TopicAutocompleteQuery, TopicA
 
   @override
   Widget buildItem(BuildContext context, int index, TopicAutocompleteResult option) {
+    final Widget child;
+    if (option.topic.displayName == null) {
+      final store = PerAccountStoreWidget.of(context);
+      child = Text(store.realmEmptyTopicDisplayName,
+        style: const TextStyle(fontStyle: FontStyle.italic));
+    } else {
+      child = Text(option.topic.displayName!);
+    }
+
     return InkWell(
       onTap: () {
         _onTapOption(context, option);
       },
       child: Padding(
         padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
-        child: Text(option.topic.displayName)));
+        child: child));
   }
 }

lib/widgets/compose_box.dart

@@ -104,13 +104,20 @@ class ComposeTopicController extends ComposeController<TopicValidationError> {
   @override
   String _computeTextNormalized() {
     String trimmed = text.trim();
-    return trimmed.isEmpty ? kNoTopicTopic : trimmed;
+    // TODO(server-10): simplify
+    if (store.connection.zulipFeatureLevel! < 334) {
+      return trimmed.isEmpty ? kNoTopicTopic : trimmed;
+    }
+
+    return trimmed;
   }
 
   @override
   List<TopicValidationError> _computeValidationErrors() {
     return [
-      if (mandatory && textNormalized == kNoTopicTopic)
+      if (mandatory && (textNormalized.isEmpty
+                        || textNormalized == kNoTopicTopic
+                        || textNormalized == store.realmEmptyTopicDisplayName))
         TopicValidationError.mandatoryButEmpty,
 
       if (
@@ -122,7 +129,7 @@ class ComposeTopicController extends ComposeController<TopicValidationError> {
   }
 
   void setTopic(TopicName newTopic) {
-    value = TextEditingValue(text: newTopic.displayName);
+    value = TextEditingValue(text: newTopic.displayName ?? '');
   }
 }
 
@@ -428,6 +435,16 @@ class _ContentInputState extends State<_ContentInput> with WidgetsBindingObserve
   @override
   Widget build(BuildContext context) {
     final designVariables = DesignVariables.of(context);
+    TextStyle hintStyle = TextStyle(
+      color: designVariables.textInput.withFadedAlpha(0.5));
+
+    if (widget.destination.destination
+        case StreamDestination(topic: TopicName(displayName: null))) {
+      // TODO(#1285): This applies to the entire hint text; ideally we'd only
+      //   want to italize the "general chat" text, but this requires
+      //   special l10n support for the hint text string.
+      hintStyle = hintStyle.copyWith(fontStyle: FontStyle.italic);
+    }
 
     return ComposeAutocomplete(
       narrow: widget.narrow,
@@ -469,8 +486,7 @@ class _ContentInputState extends State<_ContentInput> with WidgetsBindingObserve
                 // this and offering two lines of touchable area.
                 contentPadding: const EdgeInsets.symmetric(vertical: _verticalPadding),
                 hintText: widget.hintText,
-                hintStyle: TextStyle(
-                  color: designVariables.textInput.withFadedAlpha(0.5))))))));
+                hintStyle: hintStyle))))));
   }
 }
 
@@ -522,11 +538,13 @@ class _StreamContentInputState extends State<_StreamContentInput> {
     final zulipLocalizations = ZulipLocalizations.of(context);
     final streamName = store.streams[widget.narrow.streamId]?.name
       ?? zulipLocalizations.composeBoxUnknownChannelName;
+    final topic = TopicName(_topicTextNormalized);
     return _ContentInput(
       narrow: widget.narrow,
-      destination: TopicNarrow(widget.narrow.streamId, TopicName(_topicTextNormalized)),
+      destination: TopicNarrow(widget.narrow.streamId, topic),
       controller: widget.controller,
-      hintText: zulipLocalizations.composeBoxChannelContentHint(streamName, _topicTextNormalized));
+      hintText: zulipLocalizations.composeBoxChannelContentHint(
+        streamName, topic.displayName ?? store.realmEmptyTopicDisplayName));
   }
 }
 
@@ -545,6 +563,9 @@ class _TopicInput extends StatelessWidget {
       height: 22 / 20,
       color: designVariables.textInput.withFadedAlpha(0.9),
     ).merge(weightVariableTextStyle(context, wght: 600));
+    final store = PerAccountStoreWidget.of(context);
+    final allowsEmptyTopics =
+      store.connection.zulipFeatureLevel! >= 334 && !store.realmMandatoryTopics;
 
     return TopicAutocomplete(
       streamId: streamId,
@@ -562,8 +583,11 @@ class _TopicInput extends StatelessWidget {
           textInputAction: TextInputAction.next,
           style: topicTextStyle,
           decoration: InputDecoration(
-            hintText: zulipLocalizations.composeBoxTopicHintText,
+            hintText: (allowsEmptyTopics)
+              ? store.realmEmptyTopicDisplayName
+              : zulipLocalizations.composeBoxTopicHintText,
             hintStyle: topicTextStyle.copyWith(
+              fontStyle: (allowsEmptyTopics) ? FontStyle.italic : null,
               color: designVariables.textInput.withFadedAlpha(0.5))))));
   }
 }
@@ -585,7 +609,7 @@ class _FixedDestinationContentInput extends StatelessWidget {
         final streamName = store.streams[streamId]?.name
           ?? zulipLocalizations.composeBoxUnknownChannelName;
         return zulipLocalizations.composeBoxChannelContentHint(
-          streamName, topic.displayName);
+          streamName, topic.displayName ?? store.realmEmptyTopicDisplayName);
 
       case DmNarrow(otherRecipientIds: []): // The self-1:1 thread.
         return zulipLocalizations.composeBoxSelfDmContentHint;

lib/widgets/inbox.dart

@@ -526,13 +526,14 @@ class _TopicItem extends StatelessWidget {
               child: Text(
                 style: TextStyle(
                   fontSize: 17,
+                  fontStyle: (topic.displayName == null) ? FontStyle.italic : null,
                   height: (20 / 17),
                   // TODO(design) check if this is the right variable
                   color: designVariables.labelMenuButton,
                 ),
                 maxLines: 2,
                 overflow: TextOverflow.ellipsis,
-                topic.displayName))),
+                topic.displayName ?? store.realmEmptyTopicDisplayName))),
             const SizedBox(width: 12),
             if (hasMention) const _IconMarker(icon: ZulipIcons.at_sign),
             // TODO(design) copies the "@" marker color; is there a better color?

lib/widgets/message_list.dart

@@ -362,8 +362,9 @@ class MessageListAppBarTitle extends StatelessWidget {
     return Row(
       mainAxisSize: MainAxisSize.min,
       children: [
-        Flexible(child: Text(topic.displayName, style: const TextStyle(
+        Flexible(child: Text(topic.displayName ?? store.realmEmptyTopicDisplayName, style: TextStyle(
           fontSize: 13,
+          fontStyle: (topic.displayName == null) ? FontStyle.italic : null,
         ).merge(weightVariableTextStyle(context)))),
         if (icon != null)
           Padding(
@@ -1094,11 +1095,13 @@ class StreamMessageRecipientHeader extends StatelessWidget {
       child: Row(
         children: [
           Flexible(
-            child: Text(topic.displayName,
+            child: Text(topic.displayName ?? store.realmEmptyTopicDisplayName,
               // TODO: Give a way to see the whole topic (maybe a
               //   long-press interaction?)
               overflow: TextOverflow.ellipsis,
-              style: recipientHeaderTextStyle(context))),
+              style: recipientHeaderTextStyle(context).copyWith(
+                fontStyle: (topic.displayName == null) ? FontStyle.italic : null,
+              ))),
           const SizedBox(width: 4),
           // TODO(design) copies the recipient header in web; is there a better color?
           Icon(size: 14, color: designVariables.colorMessageHeaderIconInteractive,

test/api/model/model_checks.dart

@@ -48,7 +48,7 @@ extension MessageChecks on Subject<Message> {
 
 extension TopicNameChecks on Subject<TopicName> {
   Subject<String> get apiName => has((x) => x.apiName, 'apiName');
-  Subject<String> get displayName => has((x) => x.displayName, 'displayName');
+  Subject<String?> get displayName => has((x) => x.displayName, 'displayName');
 }
 
 extension StreamMessageChecks on Subject<StreamMessage> {

test/api/route/channels_test.dart

@@ -8,6 +8,30 @@ import '../../stdlib_checks.dart';
 import '../fake_api.dart';
 
 void main() {
+  test('smoke getStreamTopics', () {
+    return FakeApiConnection.with_((connection) async {
+      connection.prepare(json: GetStreamTopicsResult(topics: []).toJson());
+      await getStreamTopics(connection, streamId: 1);
+      check(connection.takeRequests()).single.isA<http.Request>()
+        ..method.equals('GET')
+        ..url.path.equals('/api/v1/users/me/1/topics')
+        ..url.queryParameters.deepEquals({
+          'allow_empty_topic_name': 'true',
+        });
+    });
+  });
+
+  test('legacy: getStreamTopics when FL < 334', () {
+    return FakeApiConnection.with_(zulipFeatureLevel: 333, (connection) async {
+      connection.prepare(json: GetStreamTopicsResult(topics: []).toJson());
+      await getStreamTopics(connection, streamId: 1);
+      check(connection.takeRequests()).single.isA<http.Request>()
+        ..method.equals('GET')
+        ..url.path.equals('/api/v1/users/me/1/topics')
+        ..url.queryParameters.deepEquals({});
+    });
+  });
+
   test('smoke updateUserTopic', () {
     return FakeApiConnection.with_((connection) async {
       connection.prepare(json: {});