TF-4236 Implement remove a label from an email when unselect in context menu Label as

lib/features/email/presentation/bindings/email_bindings.dart

@@ -5,6 +5,7 @@ import 'package:tmail_ui_user/features/email/domain/usecases/get_email_content_i
 import 'package:tmail_ui_user/features/email/domain/usecases/mark_as_email_read_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/mark_as_star_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/print_email_interactor.dart';
+import 'package:tmail_ui_user/features/email/domain/usecases/remove_a_label_from_an_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/store_opened_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/presentation/bindings/email_interactor_bindings.dart';
 import 'package:tmail_ui_user/features/email/presentation/controller/single_email_controller.dart';
@@ -25,6 +26,7 @@ class EmailBindings extends Bindings {
       Get.find<GetAllIdentitiesInteractor>(),
       Get.find<StoreOpenedEmailInteractor>(),
       Get.find<AddALabelToAnEmailInteractor>(),
+      Get.find<RemoveALabelFromAnEmailInteractor>(),
       Get.find<PrintEmailInteractor>(),
       currentEmailId: currentEmailId,
     ), tag: tag);

lib/features/email/presentation/bindings/email_interactor_bindings.dart

@@ -24,6 +24,7 @@ import 'package:tmail_ui_user/features/email/domain/usecases/mark_as_email_read_
 import 'package:tmail_ui_user/features/email/domain/usecases/mark_as_star_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/move_to_mailbox_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/print_email_interactor.dart';
+import 'package:tmail_ui_user/features/email/domain/usecases/remove_a_label_from_an_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/store_opened_email_interactor.dart';
 import 'package:tmail_ui_user/features/mailbox/data/datasource/mailbox_datasource.dart';
 import 'package:tmail_ui_user/features/mailbox/data/datasource/state_datasource.dart';
@@ -121,6 +122,9 @@ class EmailInteractorBindings extends InteractorsBindings {
     Get.lazyPut<AddALabelToAnEmailInteractor>(
       () => AddALabelToAnEmailInteractor(Get.find<EmailRepository>()),
     );
+    Get.lazyPut<RemoveALabelFromAnEmailInteractor>(
+      () => RemoveALabelFromAnEmailInteractor(Get.find<EmailRepository>()),
+    );
   }
 
   @override

lib/features/email/presentation/controller/single_email_controller.dart

@@ -47,6 +47,7 @@ import 'package:tmail_ui_user/features/email/domain/state/mark_as_email_read_sta
 import 'package:tmail_ui_user/features/email/domain/state/mark_as_email_star_state.dart';
 import 'package:tmail_ui_user/features/email/domain/state/parse_calendar_event_state.dart';
 import 'package:tmail_ui_user/features/email/domain/state/print_email_state.dart';
+import 'package:tmail_ui_user/features/email/domain/state/remove_a_label_from_an_email_state.dart';
 import 'package:tmail_ui_user/features/email/domain/state/send_receipt_to_sender_state.dart';
 import 'package:tmail_ui_user/features/email/domain/state/unsubscribe_email_state.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/add_a_label_to_an_email_interactor.dart';
@@ -60,6 +61,7 @@ import 'package:tmail_ui_user/features/email/domain/usecases/mark_as_star_email_
 import 'package:tmail_ui_user/features/email/domain/usecases/maybe_calendar_event_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/parse_calendar_event_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/print_email_interactor.dart';
+import 'package:tmail_ui_user/features/email/domain/usecases/remove_a_label_from_an_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/send_receipt_to_sender_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/store_opened_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/presentation/action/email_ui_action.dart';
@@ -119,6 +121,7 @@ class SingleEmailController extends BaseController with AppLoaderMixin {
   final StoreOpenedEmailInteractor _storeOpenedEmailInteractor;
   final PrintEmailInteractor _printEmailInteractor;
   final AddALabelToAnEmailInteractor addALabelToAnEmailInteractor;
+  final RemoveALabelFromAnEmailInteractor removeALabelFromAnEmailInteractor;
   final EmailId? _currentEmailId;
 
   CreateNewEmailRuleFilterInteractor? _createNewEmailRuleFilterInteractor;
@@ -189,6 +192,7 @@ class SingleEmailController extends BaseController with AppLoaderMixin {
     this._getAllIdentitiesInteractor,
     this._storeOpenedEmailInteractor,
     this.addALabelToAnEmailInteractor,
+    this.removeALabelFromAnEmailInteractor,
     this._printEmailInteractor, {
     EmailId? currentEmailId,
   }) : _currentEmailId = currentEmailId;
@@ -247,6 +251,8 @@ class SingleEmailController extends BaseController with AppLoaderMixin {
       calendarEventSuccess(success);
     } else if (success is AddALabelToAnEmailSuccess) {
       handleAddLabelToEmailSuccess(success);
+    } else if (success is RemoveALabelFromAnEmailSuccess) {
+      handleRemoveLabelFromEmailSuccess(success);
     } else {
       super.handleSuccessViewState(success);
     }
@@ -266,6 +272,8 @@ class SingleEmailController extends BaseController with AppLoaderMixin {
       _calendarEventFailure(failure);
     } else if (failure is AddALabelToAnEmailFailure) {
       handleAddLabelToEmailFailure(failure);
+    } else if (failure is RemoveALabelFromAnEmailFailure) {
+      handleRemoveLabelFromEmailFailure(failure);
     } else {
       super.handleFailureViewState(failure);
     }

lib/features/email/presentation/extensions/handle_label_for_email_extension.dart

@@ -1,5 +1,4 @@
 import 'package:core/utils/platform_info.dart';
-import 'package:dartz/dartz.dart';
 import 'package:jmap_dart_client/jmap/account_id.dart';
 import 'package:jmap_dart_client/jmap/core/session/session.dart';
 import 'package:jmap_dart_client/jmap/mail/email/email.dart';
@@ -8,6 +7,7 @@ import 'package:labels/extensions/label_extension.dart';
 import 'package:labels/model/label.dart';
 import 'package:model/email/presentation_email.dart';
 import 'package:tmail_ui_user/features/email/domain/state/add_a_label_to_an_email_state.dart';
+import 'package:tmail_ui_user/features/email/domain/state/remove_a_label_from_an_email_state.dart';
 import 'package:tmail_ui_user/features/email/presentation/controller/single_email_controller.dart';
 import 'package:tmail_ui_user/features/email/presentation/extensions/email_loaded_extension.dart';
 import 'package:tmail_ui_user/features/email/presentation/extensions/presentation_email_extension.dart';
@@ -27,16 +27,23 @@ extension HandleLabelForEmailExtension on SingleEmailController {
   }
 
   void toggleLabelToEmail(EmailId emailId, Label label, bool isSelected) {
-    if (isSelected) {
+    final accountId = mailboxDashBoardController.accountId.value;
-      final accountId = mailboxDashBoardController.accountId.value;
+    final session = mailboxDashBoardController.sessionCurrent;
-      final session = mailboxDashBoardController.sessionCurrent;
 
+    if (isSelected) {
       _addALabelToAnEmail(
         session: session,
         accountId: accountId,
         emailId: emailId,
         label: label,
       );
+    } else {
+      _removeALabelFromAnEmail(
+        session: session,
+        accountId: accountId,
+        emailId: emailId,
+        label: label,
+      );
     }
   }
 
@@ -49,24 +56,22 @@ extension HandleLabelForEmailExtension on SingleEmailController {
     final labelDisplay = label.safeDisplayName;
 
     if (session == null) {
-      consumeState(
+      emitFailure(
-        Stream.value(
+        controller: this,
-          Left(AddALabelToAnEmailFailure(
+        failure: AddALabelToAnEmailFailure(
-            exception: NotFoundSessionException(),
+          exception: NotFoundSessionException(),
-            labelDisplay: labelDisplay,
+          labelDisplay: labelDisplay,
-          )),
         ),
       );
       return;
     }
 
     if (accountId == null) {
-      consumeState(
+      emitFailure(
-        Stream.value(
+        controller: this,
-          Left(AddALabelToAnEmailFailure(
+        failure: AddALabelToAnEmailFailure(
-            exception: NotFoundAccountIdException(),
+          exception: NotFoundAccountIdException(),
-            labelDisplay: labelDisplay,
+          labelDisplay: labelDisplay,
-          )),
         ),
       );
       return;
@@ -74,13 +79,12 @@ extension HandleLabelForEmailExtension on SingleEmailController {
 
     final labelKeyword = label.keyword;
     if (labelKeyword == null) {
-      consumeState(
+      emitFailure(
-        Stream.value(Left(
+        controller: this,
-          AddALabelToAnEmailFailure(
+        failure: AddALabelToAnEmailFailure(
-            exception: LabelKeywordIsNull(),
+          exception: LabelKeywordIsNull(),
-            labelDisplay: labelDisplay,
+          labelDisplay: labelDisplay,
-          ),
+        ),
-        )),
       );
       return;
     }
@@ -100,6 +104,7 @@ extension HandleLabelForEmailExtension on SingleEmailController {
     _autoSyncLabelToSelectedEmailOnMemory(
       emailId: success.emailId,
       labelKeyword: success.labelKeyword,
+      remove: false,
     );
   }
 
@@ -110,11 +115,13 @@ extension HandleLabelForEmailExtension on SingleEmailController {
   void _autoSyncLabelToSelectedEmailOnMemory({
     required EmailId emailId,
     required KeyWordIdentifier labelKeyword,
+    required bool remove,
   }) {
     _updateLabelInEmailOnMemory(
       emailId: emailId,
       labelKeyword: labelKeyword,
       isMobileThreadDisabled: PlatformInfo.isMobile && !isThreadDetailEnabled,
+      remove: remove,
     );
   }
 
@@ -122,27 +129,32 @@ extension HandleLabelForEmailExtension on SingleEmailController {
     required EmailId emailId,
     required KeyWordIdentifier labelKeyword,
     required bool isMobileThreadDisabled,
+    required bool remove,
   }) {
     _updateLabelOnSelectedEmailIfNeeded(
       emailId: emailId,
       labelKeyword: labelKeyword,
       isMobileThreadDisabled: isMobileThreadDisabled,
+      remove: remove,
     );
 
     _updateLabelOnThreadIfNeeded(
       emailId: emailId,
       labelKeyword: labelKeyword,
       isMobileThreadDisabled: isMobileThreadDisabled,
+      remove: remove,
     );
 
     _updateLabelOnCurrentEmailLoaded(
       emailId: emailId,
       labelKeyword: labelKeyword,
+      remove: remove,
     );
 
     _notifyLabelUpdated(
       emailId: emailId,
       labelKeyword: labelKeyword,
+      remove: remove,
     );
   }
 
@@ -150,19 +162,21 @@ extension HandleLabelForEmailExtension on SingleEmailController {
     required EmailId emailId,
     required KeyWordIdentifier labelKeyword,
     required bool isMobileThreadDisabled,
+    required bool remove,
   }) {
     if (!isMobileThreadDisabled) return;
 
     final selectedEmail = mailboxDashBoardController.selectedEmail.value;
     if (selectedEmail?.id != emailId) return;
 
-    selectedEmail?.keywords?.addKeyword(labelKeyword);
+    selectedEmail?.keywords?.toggleKeyword(labelKeyword, remove);
   }
 
   void _updateLabelOnThreadIfNeeded({
     required EmailId emailId,
     required KeyWordIdentifier labelKeyword,
     required bool isMobileThreadDisabled,
+    required bool remove,
   }) {
     if (isMobileThreadDisabled) return;
 
@@ -173,20 +187,21 @@ extension HandleLabelForEmailExtension on SingleEmailController {
         controller.emailIdsPresentation.toggleEmailKeywordById(
       emailId: emailId,
       keyword: labelKeyword,
-      remove: false,
+      remove: remove,
     );
 
     controller.emailsInThreadDetailInfo.value =
         controller.emailsInThreadDetailInfo.toggleEmailKeywordById(
       emailId: emailId,
       keyword: labelKeyword,
-      remove: false,
+      remove: remove,
     );
   }
 
   void _updateLabelOnCurrentEmailLoaded({
     required EmailId emailId,
     required KeyWordIdentifier labelKeyword,
+    required bool remove,
   }) {
     final emailLoaded = currentEmailLoaded.value;
     if (emailLoaded == null) return;
@@ -195,17 +210,18 @@ extension HandleLabelForEmailExtension on SingleEmailController {
     currentEmailLoaded.value = emailLoaded.toggleEmailKeyword(
       emailId: emailId,
       keyword: labelKeyword,
-      remove: false,
+      remove: remove,
     );
   }
 
   void _notifyLabelUpdated({
     required EmailId emailId,
     required KeyWordIdentifier labelKeyword,
+    required bool remove,
   }) {
     mailboxDashBoardController.updateEmailFlagByEmailIds(
       [emailId],
-      isLabelAdded: true,
+      isLabelAdded: !remove,
       labelKeyword: labelKeyword,
     );
 
@@ -235,4 +251,73 @@ extension HandleLabelForEmailExtension on SingleEmailController {
       dialogLabel: 'add-label-to-email-modal',
     );
   }
+
+  void _removeALabelFromAnEmail({
+    required Session? session,
+    required AccountId? accountId,
+    required Label label,
+    required EmailId emailId,
+  }) {
+    final labelDisplay = label.safeDisplayName;
+
+    if (session == null) {
+      emitFailure(
+        controller: this,
+        failure: RemoveALabelFromAnEmailFailure(
+          exception: NotFoundSessionException(),
+          labelDisplay: labelDisplay,
+        ),
+      );
+      return;
+    }
+
+    if (accountId == null) {
+      emitFailure(
+        controller: this,
+        failure: RemoveALabelFromAnEmailFailure(
+          exception: NotFoundAccountIdException(),
+          labelDisplay: labelDisplay,
+        ),
+      );
+      return;
+    }
+
+    final labelKeyword = label.keyword;
+    if (labelKeyword == null) {
+      emitFailure(
+        controller: this,
+        failure: RemoveALabelFromAnEmailFailure(
+          exception: LabelKeywordIsNull(),
+          labelDisplay: labelDisplay,
+        ),
+      );
+      return;
+    }
+
+    consumeState(removeALabelFromAnEmailInteractor.execute(
+      session,
+      accountId,
+      emailId,
+      labelKeyword,
+      label.safeDisplayName,
+    ));
+  }
+
+  void handleRemoveLabelFromEmailSuccess(
+    RemoveALabelFromAnEmailSuccess success,
+  ) {
+    toastManager.showMessageSuccess(success);
+
+    _autoSyncLabelToSelectedEmailOnMemory(
+      emailId: success.emailId,
+      labelKeyword: success.labelKeyword,
+      remove: true,
+    );
+  }
+
+  void handleRemoveLabelFromEmailFailure(
+    RemoveALabelFromAnEmailFailure failure,
+  ) {
+    toastManager.showMessageFailure(failure);
+  }
 }

lib/features/thread/data/extensions/map_keywords_extension.dart

@@ -27,4 +27,16 @@ extension MapKeywordsExtension on Map<KeyWordIdentifier, bool>? {
   void addKeyword(KeyWordIdentifier keyword) {
     this?[keyword] = true;
   }
+
+  void removeKeyword(KeyWordIdentifier keyword) {
+    this?.remove(keyword);
+  }
+
+  void toggleKeyword(KeyWordIdentifier keyword, bool remove) {
+    if (remove) {
+      this?.remove(keyword);
+    } else {
+      this?[keyword] = true;
+    }
+  }
 }

lib/l10n/intl_messages.arb

@@ -5381,5 +5381,25 @@
     "type": "text",
     "placeholders_order": [],
     "placeholders": {}
+  },
+  "removeLabelFromEmailSuccessfullyMessage": "Email removed from the \"{labelName}\" label",
+  "@removeLabelFromEmailSuccessfullyMessage": {
+    "type": "text",
+    "placeholders_order": [
+      "labelName"
+    ],
+    "placeholders": {
+      "labelName": {}
+    }
+  },
+  "removeLabelFromEmailFailureMessage": "Cannot remove email from the \"{labelName}\" label",
+  "@removeLabelFromEmailFailureMessage": {
+    "type": "text",
+    "placeholders_order": [
+      "labelName"
+    ],
+    "placeholders": {
+      "labelName": {}
+    }
   }
 }

lib/main/localizations/app_localizations.dart

@@ -5709,4 +5709,19 @@ class AppLocalizations {
       name: 'editLabelFailure',
     );
   }
+  String removeLabelFromEmailSuccessfullyMessage(String labelName) {
+    return Intl.message(
+      'Email removed from the "$labelName" label',
+      name: 'removeLabelFromEmailSuccessfullyMessage',
+      args: [labelName],
+    );
+  }
+
+  String removeLabelFromEmailFailureMessage(String labelName) {
+    return Intl.message(
+      'Cannot remove email from the "$labelName" label',
+      name: 'removeLabelFromEmailFailureMessage',
+      args: [labelName],
+    );
+  }
 }

lib/main/utils/toast_manager.dart

@@ -28,6 +28,7 @@ import 'package:tmail_ui_user/features/email/domain/state/calendar_event_reply_s
 import 'package:tmail_ui_user/features/email/domain/state/mark_as_email_star_state.dart';
 import 'package:tmail_ui_user/features/download/domain/state/parse_email_by_blob_id_state.dart';
 import 'package:tmail_ui_user/features/download/domain/state/preview_email_from_eml_file_state.dart';
+import 'package:tmail_ui_user/features/email/domain/state/remove_a_label_from_an_email_state.dart';
 import 'package:tmail_ui_user/features/home/data/exceptions/session_exceptions.dart';
 import 'package:tmail_ui_user/features/home/domain/state/get_session_state.dart';
 import 'package:tmail_ui_user/features/labels/domain/state/create_new_label_state.dart';
@@ -212,6 +213,11 @@ class ToastManager {
           appLocalizations.addLabelToThreadFailureMessage(failure.labelDisplay);
     } else if (failure is EditLabelFailure) {
       message = message ?? appLocalizations.editLabelFailure;
+    } else if (failure is RemoveALabelFromAnEmailFailure) {
+      message = message ??
+          appLocalizations.removeLabelFromEmailFailureMessage(
+            failure.labelDisplay,
+          );
     }
     log('ToastManager::showMessageFailure: Message: $message');
     if (message?.trim().isNotEmpty == true) {
@@ -291,6 +297,10 @@ class ToastManager {
       message = appLocalizations.addLabelToThreadSuccessfullyMessage(
         success.labelDisplay,
       );
+    } else if (success is RemoveALabelFromAnEmailSuccess) {
+      message = appLocalizations.removeLabelFromEmailSuccessfullyMessage(
+        success.labelDisplay,
+      );
     }
     log('ToastManager::showMessageSuccess: Message: $message');
     if (message?.trim().isNotEmpty == true) {

model/lib/extensions/keyword_identifier_extension.dart

@@ -28,5 +28,6 @@ extension KeyWordIdentifierExtension on KeyWordIdentifier {
 
   PatchObject generateUnsubscribeActionPath() => _boolPatch(true);
 
-  PatchObject generateLabelActionPath() => _boolPatch(true);
+  PatchObject generateLabelActionPath({bool remove = false}) =>
+      _boolPatch(remove ? null : true);
 }

test/features/email/presentation/controller/single_email_controller_test.dart

@@ -36,6 +36,7 @@ import 'package:tmail_ui_user/features/email/domain/usecases/mark_as_star_email_
 import 'package:tmail_ui_user/features/email/domain/usecases/maybe_calendar_event_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/parse_calendar_event_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/print_email_interactor.dart';
+import 'package:tmail_ui_user/features/email/domain/usecases/remove_a_label_from_an_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/domain/usecases/store_opened_email_interactor.dart';
 import 'package:tmail_ui_user/features/email/presentation/action/email_ui_action.dart';
 import 'package:tmail_ui_user/features/email/presentation/controller/single_email_controller.dart';
@@ -75,6 +76,7 @@ const fallbackGenerators = {
   MockSpec<GetAllIdentitiesInteractor>(),
   MockSpec<StoreOpenedEmailInteractor>(),
   MockSpec<AddALabelToAnEmailInteractor>(),
+  MockSpec<RemoveALabelFromAnEmailInteractor>(),
   MockSpec<MailboxDashBoardController>(fallbackGenerators: fallbackGenerators),
   MockSpec<DownloadController>(fallbackGenerators: fallbackGenerators),
   MockSpec<DownloadManager>(fallbackGenerators: fallbackGenerators),
@@ -109,6 +111,7 @@ void main() {
   final getAllIdentitiesInteractor = MockGetAllIdentitiesInteractor();
   final storeOpenedEmailInteractor = MockStoreOpenedEmailInteractor();
   final addALabelToAnEmailInteractor = MockAddALabelToAnEmailInteractor();
+  final removeALabelFromAnEmailInteractor = MockRemoveALabelFromAnEmailInteractor();
   final mailboxDashboardController = MockMailboxDashBoardController();
   final downloadController = MockDownloadController();
   final downloadManager = MockDownloadManager();
@@ -175,6 +178,7 @@ void main() {
       getAllIdentitiesInteractor,
       storeOpenedEmailInteractor,
       addALabelToAnEmailInteractor,
+      removeALabelFromAnEmailInteractor,
       printEmailInteractor,
     );
   });

test/features/thread/presentation/extensions/map_keywords_extension_test.dart

@@ -171,4 +171,190 @@ void main() {
       expect(map[keyword], true);
     });
   });
+
+  group('MapKeywordsExtension - removeKeyword()', () {
+    test('removes existing keyword from map', () {
+      final keyword = KeyWordIdentifier('\$seen');
+      final map = {
+        keyword: true,
+        KeyWordIdentifier('\$flagged'): true,
+      };
+
+      map.removeKeyword(keyword);
+
+      expect(map.length, 1);
+      expect(map.containsKey(keyword), false);
+    });
+
+    test('removes keyword even if its value is false', () {
+      final keyword = KeyWordIdentifier('\$seen');
+      final map = {
+        keyword: false,
+      };
+
+      map.removeKeyword(keyword);
+
+      expect(map.isEmpty, true);
+    });
+
+    test('does nothing when keyword does not exist', () {
+      final map = {
+        KeyWordIdentifier('\$flagged'): true,
+      };
+      final keyword = KeyWordIdentifier('\$seen');
+
+      map.removeKeyword(keyword);
+
+      expect(map.length, 1);
+      expect(map.values.first, true);
+    });
+
+    test('does not throw when map is empty', () {
+      final map = <KeyWordIdentifier, bool>{};
+      final keyword = KeyWordIdentifier('\$seen');
+
+      expect(() => map.removeKeyword(keyword), returnsNormally);
+      expect(map.isEmpty, true);
+    });
+
+    test('does not throw when map is null', () {
+      Map<KeyWordIdentifier, bool>? map;
+      final keyword = KeyWordIdentifier('\$seen');
+
+      expect(() => map.removeKeyword(keyword), returnsNormally);
+    });
+
+    test('calling removeKeyword on null map has no side effects', () {
+      Map<KeyWordIdentifier, bool>? map;
+      final keyword = KeyWordIdentifier('\$seen');
+
+      map.removeKeyword(keyword);
+
+      expect(map, isNull);
+    });
+
+    test('mutates the same map instance', () {
+      final keyword = KeyWordIdentifier('\$seen');
+      final map = {
+        keyword: true,
+      };
+
+      final originalIdentity = identityHashCode(map);
+
+      map.removeKeyword(keyword);
+
+      expect(identityHashCode(map), originalIdentity);
+      expect(map.isEmpty, true);
+    });
+  });
+
+  group('MapKeywordsExtension - toggleKeyword()', () {
+    test('adds keyword when remove is false on empty map', () {
+      final keyword = KeyWordIdentifier('\$seen');
+      final map = <KeyWordIdentifier, bool>{};
+
+      map.toggleKeyword(keyword, false);
+
+      expect(map.length, 1);
+      expect(map[keyword], true);
+    });
+
+    test('adds keyword when remove is false on non-empty map', () {
+      final keyword = KeyWordIdentifier('\$seen');
+      final map = {
+        KeyWordIdentifier('\$flagged'): true,
+      };
+
+      map.toggleKeyword(keyword, false);
+
+      expect(map.length, 2);
+      expect(map[keyword], true);
+    });
+
+    test('overwrites existing keyword value to true when remove is false', () {
+      final keyword = KeyWordIdentifier('\$seen');
+      final map = {
+        keyword: false,
+      };
+
+      map.toggleKeyword(keyword, false);
+
+      expect(map.length, 1);
+      expect(map[keyword], true);
+    });
+
+    test('removes keyword when remove is true', () {
+      final keyword = KeyWordIdentifier('\$seen');
+      final map = {
+        keyword: true,
+        KeyWordIdentifier('\$flagged'): true,
+      };
+
+      map.toggleKeyword(keyword, true);
+
+      expect(map.length, 1);
+      expect(map.containsKey(keyword), false);
+    });
+
+    test('does nothing when remove is true and keyword does not exist', () {
+      final map = {
+        KeyWordIdentifier('\$flagged'): true,
+      };
+      final keyword = KeyWordIdentifier('\$seen');
+
+      map.toggleKeyword(keyword, true);
+
+      expect(map.length, 1);
+      expect(map.values.first, true);
+    });
+
+    test('does not throw when map is empty and remove is true', () {
+      final map = <KeyWordIdentifier, bool>{};
+      final keyword = KeyWordIdentifier('\$seen');
+
+      expect(() => map.toggleKeyword(keyword, true), returnsNormally);
+      expect(map.isEmpty, true);
+    });
+
+    test('adds keyword when map is empty and remove is false', () {
+      final map = <KeyWordIdentifier, bool>{};
+      final keyword = KeyWordIdentifier('\$seen');
+
+      expect(() => map.toggleKeyword(keyword, false), returnsNormally);
+      expect(map.length, 1);
+      expect(map[keyword], true);
+    });
+
+    test('does not throw when map is null', () {
+      Map<KeyWordIdentifier, bool>? map;
+      final keyword = KeyWordIdentifier('\$seen');
+
+      expect(() => map.toggleKeyword(keyword, true), returnsNormally);
+      expect(() => map.toggleKeyword(keyword, false), returnsNormally);
+    });
+
+    test('calling toggleKeyword on null map has no side effects', () {
+      Map<KeyWordIdentifier, bool>? map;
+      final keyword = KeyWordIdentifier('\$seen');
+
+      map.toggleKeyword(keyword, false);
+      map.toggleKeyword(keyword, true);
+
+      expect(map, isNull);
+    });
+
+    test('mutates the same map instance', () {
+      final keyword = KeyWordIdentifier('\$seen');
+      final map = {
+        keyword: true,
+      };
+
+      final originalIdentity = identityHashCode(map);
+
+      map.toggleKeyword(keyword, true);
+
+      expect(identityHashCode(map), originalIdentity);
+      expect(map.isEmpty, true);
+    });
+  });
 }