add either and state in interactor

lib/features/mailbox_dashboard/domain/repository/composer_cache_repository.dart

@@ -4,7 +4,7 @@ import 'package:tmail_ui_user/features/mailbox_dashboard/data/model/composer_cac
 abstract class ComposerCacheRepository {
   void saveComposerCacheOnWeb(Email email);
 
-  ComposerCache? getComposerCacheOnWeb();
+  ComposerCache getComposerCacheOnWeb();
 
   void removeComposerCacheOnWeb();
 }

lib/features/mailbox_dashboard/domain/state/get_composer_cache_state.dart

@@ -0,0 +1,21 @@
+import 'package:core/core.dart';
+import 'package:tmail_ui_user/features/mailbox_dashboard/data/model/composer_cache.dart';
+
+class GetComposerCacheSuccess extends UIState {
+
+  final ComposerCache composerCache;
+
+  GetComposerCacheSuccess(this.composerCache);
+
+  @override
+  List<Object> get props => [composerCache];
+}
+
+class GetComposerCacheFailure extends FeatureFailure {
+  final dynamic exception;
+
+  GetComposerCacheFailure(this.exception);
+
+  @override
+  List<Object> get props => [exception];
+}

lib/features/mailbox_dashboard/domain/state/remove_composer_cache_state.dart

@@ -0,0 +1,18 @@
+import 'package:core/core.dart';
+
+class RemoveComposerCacheSuccess extends UIState {
+
+  RemoveComposerCacheSuccess();
+
+  @override
+  List<Object?> get props => [];
+}
+
+class RemoveComposerCacheFailure extends FeatureFailure {
+  final dynamic exception;
+
+  RemoveComposerCacheFailure(this.exception);
+
+  @override
+  List<Object> get props => [exception];
+}

lib/features/mailbox_dashboard/domain/state/save_composer_cache_state.dart

@@ -0,0 +1,18 @@
+import 'package:core/core.dart';
+
+class SaveComposerCacheSuccess extends UIState {
+
+  SaveComposerCacheSuccess();
+
+  @override
+  List<Object> get props => [];
+}
+
+class SaveComposerCacheFailure extends FeatureFailure {
+  final dynamic exception;
+
+  SaveComposerCacheFailure(this.exception);
+
+  @override
+  List<Object> get props => [exception];
+}

lib/features/mailbox_dashboard/domain/usecases/get_composer_cache_on_web.dart

@@ -1,12 +0,0 @@
-import 'package:tmail_ui_user/features/mailbox_dashboard/data/model/composer_cache.dart';
-import 'package:tmail_ui_user/features/mailbox_dashboard/domain/repository/composer_cache_repository.dart';
-
-class GetComposerCacheOnWebInteractor {
-  final ComposerCacheRepository composerCacheRepository;
-
-  GetComposerCacheOnWebInteractor(this.composerCacheRepository);
-
-  ComposerCache? execute() {
-    return composerCacheRepository.getComposerCacheOnWeb();
-  }
-}

lib/features/mailbox_dashboard/domain/usecases/get_composer_cache_on_web_interactor.dart

@@ -0,0 +1,20 @@
+import 'package:core/presentation/state/failure.dart';
+import 'package:core/presentation/state/success.dart';
+import 'package:dartz/dartz.dart';
+import 'package:tmail_ui_user/features/mailbox_dashboard/domain/repository/composer_cache_repository.dart';
+import 'package:tmail_ui_user/features/mailbox_dashboard/domain/state/get_composer_cache_state.dart';
+
+class GetComposerCacheOnWebInteractor {
+  final ComposerCacheRepository composerCacheRepository;
+
+  GetComposerCacheOnWebInteractor(this.composerCacheRepository);
+
+  Either<Failure, Success> execute() {
+    try {
+      final data = composerCacheRepository.getComposerCacheOnWeb();
+      return Right(GetComposerCacheSuccess(data));
+    } catch (exception) {
+      return Left(GetComposerCacheFailure(exception));
+    }
+  }
+}

lib/features/mailbox_dashboard/domain/usecases/remove_composer_cache_on_web.dart

@@ -1,11 +0,0 @@
-import 'package:tmail_ui_user/features/mailbox_dashboard/domain/repository/composer_cache_repository.dart';
-
-class RemoveComposerCacheOnWebInteractor {
-  final ComposerCacheRepository composerCacheRepository;
-
-  RemoveComposerCacheOnWebInteractor(this.composerCacheRepository);
-
-  execute() {
-    return composerCacheRepository.removeComposerCacheOnWeb();
-  }
-}

lib/features/mailbox_dashboard/domain/usecases/remove_composer_cache_on_web_interactor.dart

@@ -0,0 +1,18 @@
+import 'package:dartz/dartz.dart';
+import 'package:tmail_ui_user/features/mailbox_dashboard/domain/repository/composer_cache_repository.dart';
+import 'package:tmail_ui_user/features/mailbox_dashboard/domain/state/remove_composer_cache_state.dart';
+
+class RemoveComposerCacheOnWebInteractor {
+  final ComposerCacheRepository composerCacheRepository;
+
+  RemoveComposerCacheOnWebInteractor(this.composerCacheRepository);
+
+  execute() {
+    try {
+      composerCacheRepository.removeComposerCacheOnWeb();
+      return const Right(RemoveComposerCacheSuccess);
+    } catch (exception) {
+      return Left(RemoveComposerCacheFailure(exception));
+    }
+  }
+}

lib/features/mailbox_dashboard/domain/usecases/save_composer_cache_on_web.dart

@@ -1,12 +0,0 @@
-import 'package:jmap_dart_client/jmap/mail/email/email.dart';
-import 'package:tmail_ui_user/features/mailbox_dashboard/domain/repository/composer_cache_repository.dart';
-
-class SaveComposerCacheOnWebInteractor {
-  final ComposerCacheRepository composerCacheRepository;
-
-  SaveComposerCacheOnWebInteractor(this.composerCacheRepository);
-
-   execute(Email email) {
-    return composerCacheRepository.saveComposerCacheOnWeb(email);
-  }
-}

lib/features/mailbox_dashboard/domain/usecases/save_composer_cache_on_web_interactor.dart

@@ -0,0 +1,19 @@
+import 'package:dartz/dartz.dart';
+import 'package:jmap_dart_client/jmap/mail/email/email.dart';
+import 'package:tmail_ui_user/features/mailbox_dashboard/domain/repository/composer_cache_repository.dart';
+import 'package:tmail_ui_user/features/mailbox_dashboard/domain/state/save_composer_cache_state.dart';
+
+class SaveComposerCacheOnWebInteractor {
+  final ComposerCacheRepository composerCacheRepository;
+
+  SaveComposerCacheOnWebInteractor(this.composerCacheRepository);
+
+  execute(Email email) {
+    try {
+      composerCacheRepository.saveComposerCacheOnWeb(email);
+      return const Right(SaveComposerCacheSuccess);
+    } catch (exception) {
+      return Left(SaveComposerCacheFailure(exception));
+    }
+  }
+}