TF-4195 Add Label to Thread

lib/features/thread_detail/domain/extensions/list_email_in_thread_detail_info_extension.dart

@@ -1,9 +1,12 @@
 import 'package:jmap_dart_client/jmap/mail/email/email.dart';
 import 'package:jmap_dart_client/jmap/mail/email/keyword_identifier.dart';
+import 'package:labels/model/label.dart';
+import 'package:tmail_ui_user/features/thread/data/extensions/map_keywords_extension.dart';
 import 'package:tmail_ui_user/features/thread_detail/domain/extensions/email_in_thread_detail_info_extension.dart';
 import 'package:tmail_ui_user/features/thread_detail/domain/model/email_in_thread_detail_info.dart';
 
-extension ListEmailInThreadDetailInfoExtension on List<EmailInThreadDetailInfo> {
+extension ListEmailInThreadDetailInfoExtension
+    on List<EmailInThreadDetailInfo> {
   List<EmailId> emailIdsToDisplay(bool isSentMailbox) => isSentMailbox
       ? map((email) => email.emailId).toList()
       : where((email) => email.isValidToDisplay)
@@ -22,4 +25,48 @@ extension ListEmailInThreadDetailInfoExtension on List<EmailInThreadDetailInfo>
       return emailInfo.toggleKeyword(keyword, remove);
     }).toList();
   }
-}
+
+  List<EmailInThreadDetailInfo> toggleListEmailsKeywordByIds({
+    required List<EmailId> emailIds,
+    required KeyWordIdentifier keyword,
+    required bool remove,
+  }) {
+    final targetIds = emailIds.toSet();
+
+    return map((emailInfo) {
+      if (!targetIds.contains(emailInfo.emailId)) {
+        return emailInfo;
+      }
+
+      return emailInfo.toggleKeyword(keyword, remove);
+    }).toList();
+  }
+
+  List<Label> findCommonLabelsInThread({
+    required List<Label> labels,
+  }) {
+    if (isEmpty || labels.isEmpty) return const [];
+
+    final iterator = where((e) => e.isValidToDisplay).iterator;
+    if (!iterator.moveNext()) return const [];
+
+    // Initialize with the first valid email
+    var commonKeywords = iterator.current.keywords.enabledKeywordSet;
+
+    if (commonKeywords.isEmpty) return const [];
+
+    // Intersect with remaining emails
+    while (iterator.moveNext()) {
+      commonKeywords = commonKeywords.intersection(
+        iterator.current.keywords.enabledKeywordSet,
+      );
+
+      if (commonKeywords.isEmpty) return const [];
+    }
+
+    return labels
+        .where((label) =>
+            label.keyword != null && commonKeywords.contains(label.keyword))
+        .toList();
+  }
+}