TF-82 Create an email as drafts

lib/features/composer/domain/state/save_email_as_drafts_state.dart

@@ -0,0 +1,21 @@
+import 'package:core/core.dart';
+import 'package:jmap_dart_client/jmap/mail/email/email.dart';
+
+class SaveEmailAsDraftsSuccess extends UIState {
+
+  final Email emailAsDrafts;
+
+  SaveEmailAsDraftsSuccess(this.emailAsDrafts);
+
+  @override
+  List<Object?> get props => [];
+}
+
+class SaveEmailAsDraftsFailure extends FeatureFailure {
+  final exception;
+
+  SaveEmailAsDraftsFailure(this.exception);
+
+  @override
+  List<Object> get props => [exception];
+}

lib/features/composer/domain/usecases/save_email_as_drafts_interactor.dart

@@ -0,0 +1,25 @@
+import 'package:core/core.dart';
+import 'package:dartz/dartz.dart';
+import 'package:jmap_dart_client/jmap/account_id.dart';
+import 'package:jmap_dart_client/jmap/mail/email/email.dart';
+import 'package:tmail_ui_user/features/composer/domain/state/save_email_as_drafts_state.dart';
+import 'package:tmail_ui_user/features/email/domain/repository/email_repository.dart';
+
+class SaveEmailAsDraftsInteractor {
+  final EmailRepository emailRepository;
+
+  SaveEmailAsDraftsInteractor(this.emailRepository);
+
+  Stream<Either<Failure, Success>> execute(AccountId accountId, Email email) async* {
+    try {
+      final result = await emailRepository.saveEmailAsDrafts(accountId, email);
+      if (result) {
+        yield Right<Failure, Success>(SaveEmailAsDraftsSuccess(email));
+      } else {
+        yield Left<Failure, Success>(SaveEmailAsDraftsFailure(result));
+      }
+    } catch (e) {
+      yield Left<Failure, Success>(SaveEmailAsDraftsFailure(e));
+    }
+  }
+}