action_sheet: Add "Mark as unread from here" button

Fixes: zulip#131

Author: Khader-1

assets/l10n/app_en.arb

@@ -51,6 +51,10 @@
   "@actionSheetOptionCopyMessageLink": {
     "description": "Label for copy message link button on action sheet."
   },
+  "actionSheetMarkAsUnread": "Mark as unread from here",
+  "@actionSheetMarkAsUnread":  {
+    "description": "Label for mark as unread button on action sheet."
+  },
   "actionSheetOptionShare": "Share",
   "@actionSheetOptionShare":  {
     "description": "Label for share button on action sheet."
@@ -432,6 +436,21 @@
   "@errorMarkAsReadFailedTitle": {
     "description": "Error title when mark as read action failed."
   },
+  "markAsUnreadComplete": "Marked {num, plural, =1{1 message} other{{num} messages}} as unread.",
+  "@markAsUnreadComplete": {
+    "description": "Message when marking messages as unread has completed.",
+    "placeholders": {
+      "num": {"type": "int", "example": "4"}
+    }
+  },
+  "markAsUnreadInProgress": "Marking messages as unread...",
+  "@markAsUnreadInProgress": {
+    "description": "Progress message when marking messages as unread."
+  },
+  "errorMarkAsUnreadFailedTitle": "Mark as unread failed",
+  "@errorMarkAsUnreadFailedTitle": {
+    "description": "Error title when mark as unread action failed."
+  },
   "today": "Today",
   "@today": {
     "description": "Term to use to reference the current day."

lib/widgets/action_sheet.dart

@@ -8,6 +8,7 @@ import '../api/model/model.dart';
 import '../api/route/messages.dart';
 import '../model/internal_link.dart';
 import '../model/narrow.dart';
+import 'actions.dart';
 import 'clipboard.dart';
 import 'compose_box.dart';
 import 'dialog.dart';
@@ -36,6 +37,8 @@ void showMessageActionSheet({required BuildContext context, required Message mes
       && reactionWithVotes.userIds.contains(store.selfUserId))
     ?? false;
 
+  final isMessageRead = message.flags.contains(MessageFlag.read);
+
   showDraggableScrollableModalBottomSheet<void>(
     context: context,
     builder: (BuildContext _) {
@@ -46,6 +49,7 @@ void showMessageActionSheet({required BuildContext context, required Message mes
           message: message,
           messageListContext: context,
         ),
+        if (isMessageRead) MarkAsUnreadButton(message: message, messageListContext: context),
         CopyMessageTextButton(message: message, messageListContext: context),
         CopyMessageLinkButton(message: message, messageListContext: context),
         ShareButton(message: message, messageListContext: context),
@@ -402,3 +406,25 @@ class ShareButton extends MessageActionSheetMenuItemButton {
     }
   }
 }
+
+class MarkAsUnreadButton extends MessageActionSheetMenuItemButton {
+  MarkAsUnreadButton({
+    super.key,
+    required super.message,
+    required super.messageListContext,
+  }) : narrow = MessageListPage.ancestorOf(messageListContext).narrow;
+
+  final Narrow narrow;
+
+  @override IconData get icon => Icons.mark_chat_unread_outlined;
+
+  @override
+  String label(ZulipLocalizations zulipLocalizations) {
+    return zulipLocalizations.actionSheetMarkAsUnread;
+  }
+
+  @override void onPressed(BuildContext context) async {
+    Navigator.of(context).pop();
+    await markNarrowAsUnreadFromMessage(messageListContext, message, narrow);
+  }
+}

lib/widgets/actions.dart

@@ -53,6 +53,25 @@ Future<bool> markNarrowAsRead(
     onProgressTitle: zulipLocalizations.markAsReadInProgress);
 }
 
+Future<bool> markNarrowAsUnreadFromMessage(
+  BuildContext context,
+  Message message,
+  Narrow narrow,
+) async {
+  final zulipLocalizations = ZulipLocalizations.of(context);
+
+  return updateMessageFlagsStartingFromAnchor(
+    context: context,
+    startAnchor: NumericAnchor(message.id),
+    apiNarrow: narrow.apiEncode(),
+    includeAnchor: true,
+    op: UpdateMessageFlagsOp.remove,
+    flag: MessageFlag.read,
+    onCompletedMessage: zulipLocalizations.markAsUnreadComplete,
+    onFailedTitle: zulipLocalizations.errorMarkAsUnreadFailedTitle,
+    onProgressTitle: zulipLocalizations.markAsUnreadInProgress);
+}
+
 Future<bool> updateMessageFlagsStartingFromAnchor({
   required BuildContext context,
   required Anchor startAnchor,

test/widgets/action_sheet_test.dart

@@ -545,4 +545,20 @@ void main() {
       check(mockSharePlus.sharedString).isNull();
     });
   });
+
+  group('MarkAsUnread', () {
+    testWidgets('not visible if message is not read', (WidgetTester tester) async {
+      final unreadMessage = eg.streamMessage(flags: []);
+      await setupToMessageActionSheet(tester, message: unreadMessage, narrow: TopicNarrow.ofMessage(unreadMessage));
+
+      check(find.byIcon(Icons.mark_chat_unread_outlined).evaluate().length).equals(0);
+    });
+
+    testWidgets('visible if message is read', (WidgetTester tester) async {
+      final message = eg.streamMessage(flags: [MessageFlag.read]);
+      await setupToMessageActionSheet(tester, message: message, narrow: TopicNarrow.ofMessage(message));
+
+      check(find.byIcon(Icons.mark_chat_unread_outlined).evaluate().length).equals(1);
+    });
+  });
 }