action_sheet: Add channel action sheet with mark as read option

Fixes: #1226

Author: chimnayajith

assets/l10n/app_en.arb

@@ -76,6 +76,10 @@
   "@permissionsDeniedReadExternalStorage": {
     "description": "Message for dialog asking the user to grant permissions for external storage read access."
   },
+  "actionSheetOptionMarkChannelAsRead": "Mark channel as read",
+  "@actionSheetOptionMarkChannelAsRead": {
+    "description": "Label for marking a channel as read."
+  },
   "actionSheetOptionMuteTopic": "Mute topic",
   "@actionSheetOptionMuteTopic":  {
     "description": "Label for muting a topic on action sheet."

lib/generated/l10n/zulip_localizations.dart

@@ -219,6 +219,12 @@ abstract class ZulipLocalizations {
   /// **'To upload files, please grant Zulip additional permissions in Settings.'**
   String get permissionsDeniedReadExternalStorage;
 
+  /// Label for marking a channel as read.
+  ///
+  /// In en, this message translates to:
+  /// **'Mark channel as read'**
+  String get actionSheetOptionMarkChannelAsRead;
+
   /// Label for muting a topic on action sheet.
   ///
   /// In en, this message translates to:

lib/generated/l10n/zulip_localizations_ar.dart

@@ -67,6 +67,9 @@ class ZulipLocalizationsAr extends ZulipLocalizations {
   @override
   String get permissionsDeniedReadExternalStorage => 'To upload files, please grant Zulip additional permissions in Settings.';
 
+  @override
+  String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
+
   @override
   String get actionSheetOptionMuteTopic => 'Mute topic';
 

lib/generated/l10n/zulip_localizations_en.dart

@@ -67,6 +67,9 @@ class ZulipLocalizationsEn extends ZulipLocalizations {
   @override
   String get permissionsDeniedReadExternalStorage => 'To upload files, please grant Zulip additional permissions in Settings.';
 
+  @override
+  String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
+
   @override
   String get actionSheetOptionMuteTopic => 'Mute topic';
 

lib/generated/l10n/zulip_localizations_ja.dart

@@ -67,6 +67,9 @@ class ZulipLocalizationsJa extends ZulipLocalizations {
   @override
   String get permissionsDeniedReadExternalStorage => 'To upload files, please grant Zulip additional permissions in Settings.';
 
+  @override
+  String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
+
   @override
   String get actionSheetOptionMuteTopic => 'Mute topic';
 

lib/generated/l10n/zulip_localizations_nb.dart

@@ -67,6 +67,9 @@ class ZulipLocalizationsNb extends ZulipLocalizations {
   @override
   String get permissionsDeniedReadExternalStorage => 'To upload files, please grant Zulip additional permissions in Settings.';
 
+  @override
+  String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
+
   @override
   String get actionSheetOptionMuteTopic => 'Mute topic';
 

lib/generated/l10n/zulip_localizations_pl.dart

@@ -67,6 +67,9 @@ class ZulipLocalizationsPl extends ZulipLocalizations {
   @override
   String get permissionsDeniedReadExternalStorage => 'Aby odebrać pliki Zulip musi uzyskać dodatkowe uprawnienia w Ustawieniach.';
 
+  @override
+  String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
+
   @override
   String get actionSheetOptionMuteTopic => 'Wycisz wątek';
 

lib/generated/l10n/zulip_localizations_ru.dart

@@ -67,6 +67,9 @@ class ZulipLocalizationsRu extends ZulipLocalizations {
   @override
   String get permissionsDeniedReadExternalStorage => 'Для загрузки файлов, пожалуйста, предоставьте Zulip дополнительные разрешения в настройках.';
 
+  @override
+  String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
+
   @override
   String get actionSheetOptionMuteTopic => 'Отключить тему';
 

lib/generated/l10n/zulip_localizations_sk.dart

@@ -67,6 +67,9 @@ class ZulipLocalizationsSk extends ZulipLocalizations {
   @override
   String get permissionsDeniedReadExternalStorage => 'To upload files, please grant Zulip additional permissions in Settings.';
 
+  @override
+  String get actionSheetOptionMarkChannelAsRead => 'Mark channel as read';
+
   @override
   String get actionSheetOptionMuteTopic => 'Stlmiť tému';
 

lib/widgets/action_sheet.dart

@@ -162,6 +162,58 @@ class ActionSheetCancelButton extends StatelessWidget {
   }
 }
 
+/// Show a sheet of actions you can take on a channel.
+void showChannelActionSheet(BuildContext context, {
+  required int streamId,
+}) {
+  final store = PerAccountStoreWidget.of(context);
+
+  final optionButtons = <ActionSheetMenuItemButton>[];
+  final unreadCount = store.unreads.countInChannelNarrow(streamId);
+  if (unreadCount > 0) {
+    optionButtons.add(
+      MarkChannelAsReadButton(
+        streamId: streamId,
+        pageContext: context,
+      ),
+    );
+  }
+  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(context, optionButtons: optionButtons);
+}
+
+class MarkChannelAsReadButton extends ActionSheetMenuItemButton {
+  const MarkChannelAsReadButton({
+    super.key,
+    required this.streamId,
+    required super.pageContext
+  });
+
+  final int streamId;
+
+  @override
+  IconData get icon => ZulipIcons.message_checked;
+
+  @override
+  String label(ZulipLocalizations zulipLocalizations) {
+    return zulipLocalizations.actionSheetOptionMarkChannelAsRead;
+  }
+
+  @override
+  void onPressed() async {
+    final narrow = ChannelNarrow(streamId);
+    await ZulipAction.markNarrowAsRead(pageContext, narrow);
+  }
+}
+
 /// Show a sheet of actions you can take on a topic.
 void showTopicActionSheet(BuildContext context, {
   required int channelId,