TF-1684 Add abstract TransformHtmlSignature method

(cherry picked from commit dfaa5187d1b6a6c1065c65699b6e3a287d1d0843)

lib/features/manage_account/domain/repository/identity_repository.dart

@@ -14,4 +14,6 @@ abstract class IdentityRepository {
   Future<bool> deleteIdentity(Session session, AccountId accountId, IdentityId identityId);
 
   Future<bool> editIdentity(Session session, AccountId accountId, EditIdentityRequest editIdentityRequest);
+
+  Future<String> transformHtmlSignature(String signature);
 }

lib/features/manage_account/domain/state/transform_html_signature_state.dart

@@ -0,0 +1,27 @@
+import 'package:core/presentation/state/failure.dart';
+import 'package:core/presentation/state/success.dart';
+
+class TransformHtmlSignatureLoading extends UIState {
+
+  TransformHtmlSignatureLoading();
+
+  @override
+  List<Object?> get props => [];
+}
+
+class TransformHtmlSignatureSuccess extends UIState {
+  final String signature;
+
+  TransformHtmlSignatureSuccess(this.signature);
+
+  @override
+  List<Object?> get props => [signature];
+}
+
+class TransformHtmlSignatureFailure extends FeatureFailure {
+
+  TransformHtmlSignatureFailure(exception) : super(exception: exception);
+
+  @override
+  List<Object?> get props => [exception];
+}

lib/features/manage_account/domain/usecases/transform_html_signature_interactor.dart

@@ -0,0 +1,24 @@
+import 'dart:core';
+
+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/manage_account/domain/repository/identity_repository.dart';
+import 'package:tmail_ui_user/features/manage_account/domain/state/edit_identity_state.dart';
+import 'package:tmail_ui_user/features/manage_account/domain/state/transform_html_signature_state.dart';
+
+class TransformHtmlSignatureInteractor {
+  final IdentityRepository _identityRepository;
+
+  TransformHtmlSignatureInteractor(this._identityRepository);
+
+  Stream<Either<Failure, Success>> execute(String signature) async* {
+    try {
+      yield Right<Failure, Success>(TransformHtmlSignatureLoading());
+      final signatureUnescape = await _identityRepository.transformHtmlSignature(signature);
+      yield Right<Failure, Success>(TransformHtmlSignatureSuccess(signatureUnescape));
+    } catch (exception) {
+      yield Left<Failure, Success>(EditIdentityFailure(exception));
+    }
+  }
+}