msglist: Support adding a thumbs-up reaction

Fixes: zulip#125

lib/widgets/action_sheet.dart

@@ -17,15 +17,27 @@ import 'store.dart';
 ///
 /// Must have a [MessageListPage] ancestor.
 void showMessageActionSheet({required BuildContext context, required Message message}) {
+  final store = PerAccountStoreWidget.of(context);
+
   // The UI that's conditioned on this won't live-update during this appearance
   // of the action sheet (we avoid calling composeBoxControllerOf in a build
   // method; see its doc). But currently it will be constant through the life of
   // any message list, so that's fine.
   final isComposeBoxOffered = MessageListPage.composeBoxControllerOf(context) != null;
+
+  final selfUserId = store.account.userId;
+  final hasThumbsUpReactionVote = message.reactions
+    ?.aggregated.any((reactionWithVotes) =>
+      reactionWithVotes.reactionType == ReactionType.unicodeEmoji
+      && reactionWithVotes.emojiCode == '1f44d'
+      && reactionWithVotes.userIds.contains(selfUserId))
+    ?? false;
+
   showDraggableScrollableModalBottomSheet(
     context: context,
     builder: (BuildContext _) {
       return Column(children: [
+        if (!hasThumbsUpReactionVote) AddThumbsUpButton(message: message, messageListContext: context),
         ShareButton(message: message, messageListContext: context),
         if (isComposeBoxOffered) QuoteAndReplyButton(
           message: message,
@@ -60,6 +72,49 @@ abstract class MessageActionSheetMenuItemButton extends StatelessWidget {
   }
 }
 
+// This button is very temporary, to complete #125 before we have a way to
+// choose an arbitrary reaction (#388). So, skipping i18n.
+class AddThumbsUpButton extends MessageActionSheetMenuItemButton {
+  AddThumbsUpButton({
+    super.key,
+    required super.message,
+    required super.messageListContext,
+  });
+
+  @override get icon => Icons.add_reaction_outlined;
+
+  @override
+  String label(ZulipLocalizations zulipLocalizations) {
+    return 'React with 👍'; // TODO(i18n) skip translation for now
+  }
+
+  @override get onPressed => (BuildContext context) async {
+    Navigator.of(context).pop();
+    String? errorMessage;
+    try {
+      await addReaction(PerAccountStoreWidget.of(messageListContext).connection,
+        messageId: message.id,
+        reactionType: ReactionType.unicodeEmoji,
+        emojiCode: '1f44d',
+        emojiName: '+1',
+      );
+    } catch (e) {
+      if (!messageListContext.mounted) return;
+
+      switch (e) {
+        case ZulipApiException():
+          errorMessage = e.message;
+          // TODO specific messages for common errors, like network errors
+          //   (support with reusable code)
+        default:
+      }
+
+      await showErrorDialog(context: context,
+        title: 'Adding reaction failed', message: errorMessage);
+    }
+  };
+}
+
 class ShareButton extends MessageActionSheetMenuItemButton {
   ShareButton({
     super.key,

test/widgets/action_sheet_test.dart

@@ -3,6 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_gen/gen_l10n/zulip_localizations.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:http/http.dart' as http;
 import 'package:zulip/api/model/model.dart';
 import 'package:zulip/api/route/messages.dart';
 import 'package:zulip/model/compose.dart';
@@ -19,6 +20,7 @@ import '../example_data.dart' as eg;
 import '../flutter_checks.dart';
 import '../model/binding.dart';
 import '../model/test_store.dart';
+import '../stdlib_checks.dart';
 import '../test_clipboard.dart';
 import '../test_share_plus.dart';
 import 'compose_box_checks.dart';
@@ -91,6 +93,54 @@ void main() {
     (store.connection as FakeApiConnection).prepare(httpStatus: 400, json: fakeResponseJson);
   }
 
+  group('AddThumbsUpButton', () {
+    Future<void> tapButton(WidgetTester tester) async {
+      await tester.ensureVisible(find.byIcon(Icons.add_reaction_outlined, skipOffstage: false));
+      await tester.tap(find.byIcon(Icons.add_reaction_outlined));
+      await tester.pump(); // [MenuItemButton.onPressed] called in a post-frame callback: flutter/flutter@e4a39fa2e
+    }
+
+    testWidgets('success', (WidgetTester tester) async {
+      final message = eg.streamMessage();
+      await setupToMessageActionSheet(tester, message: message, narrow: TopicNarrow.ofMessage(message));
+      final store = await testBinding.globalStore.perAccount(eg.selfAccount.id);
+
+      final connection = store.connection as FakeApiConnection;
+      connection.prepare(json: {});
+      await tapButton(tester);
+      await tester.pump(Duration.zero);
+
+      check(connection.lastRequest).isA<http.Request>()
+        ..method.equals('POST')
+        ..url.path.equals('/api/v1/messages/${message.id}/reactions')
+        ..bodyFields.deepEquals({
+            'reaction_type': 'unicode_emoji',
+            'emoji_code': '1f44d',
+            'emoji_name': '+1',
+          });
+    });
+
+    testWidgets('request has an error', (WidgetTester tester) async {
+      final message = eg.streamMessage();
+      await setupToMessageActionSheet(tester, message: message, narrow: TopicNarrow.ofMessage(message));
+      final store = await testBinding.globalStore.perAccount(eg.selfAccount.id);
+
+      final connection = store.connection as FakeApiConnection;
+
+      connection.prepare(httpStatus: 400, json: {
+        'code': 'BAD_REQUEST',
+        'msg': 'Invalid message(s)',
+        'result': 'error',
+      });
+      await tapButton(tester);
+      await tester.pump(Duration.zero); // error arrives; error dialog shows
+
+      await tester.tap(find.byWidget(checkErrorDialog(tester,
+        expectedTitle: 'Adding reaction failed',
+        expectedMessage: 'Invalid message(s)')));
+    });
+  });
+
   group('ShareButton', () {
     // Tests should call this.
     MockSharePlus setupMockSharePlus() {
@@ -169,6 +219,7 @@ void main() {
     ///
     /// Checks that there is a quote-and-reply button.
     Future<void> tapQuoteAndReplyButton(WidgetTester tester) async {
+      await tester.ensureVisible(find.byIcon(Icons.format_quote_outlined, skipOffstage: false));
       final quoteAndReplyButton = findQuoteAndReplyButton(tester);
       check(quoteAndReplyButton).isNotNull();
       await tester.tap(find.byWidget(quoteAndReplyButton!));