topics: Add TopicListButton to channel action sheet

The icon was taken from CZO discussion:
  https://chat.zulip.org/#narrow/channel/530-mobile-design/topic/Topic.20list.20in.20channel/near/2140324

Fixes: #1158

Co-authored-by: Zixuan James Li <[email protected]>

Author: lakshya1goel

assets/icons/ZulipIcons.ttf

@@ -84,6 +84,10 @@
   "@actionSheetOptionMarkChannelAsRead": {
     "description": "Label for marking a channel as read."
   },
+  "actionSheetOptionTopicList": "Topic list",
+  "@actionSheetOptionTopicList": {
+    "description": "Label for navigating to a channel's topic-list page."
+  },
   "actionSheetOptionMuteTopic": "Mute topic",
   "@actionSheetOptionMuteTopic":  {
     "description": "Label for muting a topic on action sheet."

assets/icons/topics.svg

@@ -236,6 +236,12 @@ abstract class ZulipLocalizations {
   /// **'Mark channel as read'**
   String get actionSheetOptionMarkChannelAsRead;
 
+  /// Label for navigating to a channel's topic-list page.
+  ///
+  /// In en, this message translates to:
+  /// **'Topic list'**
+  String get actionSheetOptionTopicList;
+
   /// Label for muting a topic on action sheet.
   ///
   /// In en, this message translates to:

assets/l10n/app_en.arb

@@ -76,6 +76,9 @@ class ZulipLocalizationsAr extends ZulipLocalizations {
   @override
   String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
 
+  @override
+  String get actionSheetOptionTopicList => 'Topic list';
+
   @override
   String get actionSheetOptionMuteTopic => 'Mute topic';
 

lib/generated/l10n/zulip_localizations.dart

@@ -76,6 +76,9 @@ class ZulipLocalizationsEn extends ZulipLocalizations {
   @override
   String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
 
+  @override
+  String get actionSheetOptionTopicList => 'Topic list';
+
   @override
   String get actionSheetOptionMuteTopic => 'Mute topic';
 

lib/generated/l10n/zulip_localizations_ar.dart

@@ -76,6 +76,9 @@ class ZulipLocalizationsJa extends ZulipLocalizations {
   @override
   String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
 
+  @override
+  String get actionSheetOptionTopicList => 'Topic list';
+
   @override
   String get actionSheetOptionMuteTopic => 'Mute topic';
 

lib/generated/l10n/zulip_localizations_en.dart

@@ -76,6 +76,9 @@ class ZulipLocalizationsNb extends ZulipLocalizations {
   @override
   String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
 
+  @override
+  String get actionSheetOptionTopicList => 'Topic list';
+
   @override
   String get actionSheetOptionMuteTopic => 'Mute topic';
 

lib/generated/l10n/zulip_localizations_ja.dart

@@ -78,6 +78,9 @@ class ZulipLocalizationsPl extends ZulipLocalizations {
   String get actionSheetOptionMarkChannelAsRead =>
       'Oznacz kanał jako przeczytany';
 
+  @override
+  String get actionSheetOptionTopicList => 'Topic list';
+
   @override
   String get actionSheetOptionMuteTopic => 'Wycisz wątek';
 

lib/generated/l10n/zulip_localizations_nb.dart

@@ -78,6 +78,9 @@ class ZulipLocalizationsRu extends ZulipLocalizations {
   String get actionSheetOptionMarkChannelAsRead =>
       'Отметить канал как прочитанный';
 
+  @override
+  String get actionSheetOptionTopicList => 'Topic list';
+
   @override
   String get actionSheetOptionMuteTopic => 'Отключить тему';
 

lib/generated/l10n/zulip_localizations_pl.dart

@@ -76,6 +76,9 @@ class ZulipLocalizationsSk extends ZulipLocalizations {
   @override
   String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
 
+  @override
+  String get actionSheetOptionTopicList => 'Topic list';
+
   @override
   String get actionSheetOptionMuteTopic => 'Stlmiť tému';
 

lib/generated/l10n/zulip_localizations_ru.dart

@@ -79,6 +79,9 @@ class ZulipLocalizationsUk extends ZulipLocalizations {
   String get actionSheetOptionMarkChannelAsRead =>
       'Позначити канал як прочитаний';
 
+  @override
+  String get actionSheetOptionTopicList => 'Topic list';
+
   @override
   String get actionSheetOptionMuteTopic => 'Заглушити тему';
 

lib/generated/l10n/zulip_localizations_sk.dart

@@ -28,6 +28,7 @@ import 'page.dart';
 import 'store.dart';
 import 'text.dart';
 import 'theme.dart';
+import 'topic_list.dart';
 
 void _showActionSheet(
   BuildContext context, {
@@ -174,24 +175,43 @@ void showChannelActionSheet(BuildContext context, {
   final pageContext = PageRoot.contextOf(context);
   final store = PerAccountStoreWidget.of(pageContext);
 
-  final optionButtons = <ActionSheetMenuItemButton>[];
+  final optionButtons = <ActionSheetMenuItemButton>[
+    TopicListButton(pageContext: pageContext, channelId: channelId),
+  ];
+
   final unreadCount = store.unreads.countInChannelNarrow(channelId);
   if (unreadCount > 0) {
     optionButtons.add(
       MarkChannelAsReadButton(pageContext: pageContext, channelId: channelId));
   }
-  if (optionButtons.isEmpty) {
-    // TODO(a11y): This case makes a no-op gesture handler; as a consequence,
-    //   we're presenting some UI (to people who use screen-reader software) as
-    //   though it offers a gesture interaction that it doesn't meaningfully
-    //   offer, which is confusing. The solution here is probably to remove this
-    //   is-empty case by having at least one button that's always present,
-    //   such as "copy link to channel".
-    return;
-  }
+
   _showActionSheet(pageContext, optionButtons: optionButtons);
 }
 
+class TopicListButton extends ActionSheetMenuItemButton {
+  const TopicListButton({
+    super.key,
+    required this.channelId,
+    required super.pageContext,
+  });
+
+  final int channelId;
+
+  @override
+  IconData get icon => ZulipIcons.topics;
+
+  @override
+  String label(ZulipLocalizations zulipLocalizations) {
+    return zulipLocalizations.actionSheetOptionTopicList;
+  }
+
+  @override
+  void onPressed() {
+    Navigator.push(pageContext,
+      TopicListPage.buildRoute(context: pageContext, streamId: channelId));
+  }
+}
+
 class MarkChannelAsReadButton extends ActionSheetMenuItemButton {
   const MarkChannelAsReadButton({
     super.key,

lib/generated/l10n/zulip_localizations_uk.dart

@@ -147,11 +147,14 @@ abstract final class ZulipIcons {
   /// The Zulip custom icon "topic".
   static const IconData topic = IconData(0xf129, fontFamily: "Zulip Icons");
 
+  /// The Zulip custom icon "topics".
+  static const IconData topics = IconData(0xf12a, fontFamily: "Zulip Icons");
+
   /// The Zulip custom icon "unmute".
-  static const IconData unmute = IconData(0xf12a, fontFamily: "Zulip Icons");
+  static const IconData unmute = IconData(0xf12b, fontFamily: "Zulip Icons");
 
   /// The Zulip custom icon "user".
-  static const IconData user = IconData(0xf12b, fontFamily: "Zulip Icons");
+  static const IconData user = IconData(0xf12c, fontFamily: "Zulip Icons");
 
   // END GENERATED ICON DATA
 }

lib/widgets/action_sheet.dart

@@ -201,6 +201,7 @@ void main() {
       void checkButtons() {
         check(actionSheetFinder).findsOne();
         checkButton('Mark channel as read');
+        checkButton('Topic list');
       }
 
       testWidgets('show from inbox', (tester) async {
@@ -218,7 +219,7 @@ void main() {
       testWidgets('show with no unread messages', (tester) async {
         await prepare(hasUnreadMessages: false);
         await showFromSubscriptionList(tester);
-        check(actionSheetFinder).findsNothing();
+        check(findButtonForLabel('Mark channel as read')).findsNothing();
       });
 
       testWidgets('show from app bar in channel narrow', (tester) async {
@@ -242,6 +243,19 @@ void main() {
       });
     });
 
+    testWidgets('TopicListButton', (tester) async {
+      await prepare();
+      await showFromAppBar(tester,
+        narrow: ChannelNarrow(someChannel.streamId));
+
+      connection.prepare(json: GetStreamTopicsResult(topics: [
+        eg.getStreamTopicsEntry(name: 'some topic foo'),
+      ]).toJson());
+      await tester.tap(findButtonForLabel('Topic list'));
+      await tester.pumpAndSettle();
+      check(find.text('some topic foo')).findsOne();
+    });
+
     group('MarkChannelAsReadButton', () {
       void checkRequest(int channelId) {
         check(connection.takeRequests()).single.isA<http.Request>()