TF-825 Add download message as EML method in interactor

lib/features/email/domain/state/download_message_as_eml_state.dart

@@ -0,0 +1,11 @@
+import 'package:core/presentation/state/failure.dart';
+import 'package:core/presentation/state/success.dart';
+
+class StartDownloadMessageAsEML extends LoadingState {}
+
+class DownloadMessageAsEMLSuccess extends UIState {}
+
+class DownloadMessageAsEMLFailure extends FeatureFailure {
+
+  DownloadMessageAsEMLFailure(dynamic exception) : super(exception: exception);
+}

lib/features/email/domain/usecases/download_message_as_eml_interactor.dart

@@ -0,0 +1,66 @@
+import 'dart:async';
+
+import 'package:core/presentation/state/failure.dart';
+import 'package:core/presentation/state/success.dart';
+import 'package:dartz/dartz.dart';
+import 'package:jmap_dart_client/jmap/account_id.dart';
+import 'package:jmap_dart_client/jmap/core/id.dart';
+import 'package:jmap_dart_client/jmap/core/user_name.dart';
+import 'package:model/account/account_request.dart';
+import 'package:model/account/authentication_type.dart';
+import 'package:model/account/password.dart';
+import 'package:tmail_ui_user/features/email/domain/repository/email_repository.dart';
+import 'package:tmail_ui_user/features/email/domain/state/download_message_as_eml_state.dart';
+import 'package:tmail_ui_user/features/login/domain/repository/account_repository.dart';
+import 'package:tmail_ui_user/features/login/domain/repository/authentication_oidc_repository.dart';
+import 'package:tmail_ui_user/features/login/domain/repository/credential_repository.dart';
+
+class DownloadMessageAsEMLInteractor {
+  final EmailRepository _emailRepository;
+  final CredentialRepository _credentialRepository;
+  final AccountRepository _accountRepository;
+  final AuthenticationOIDCRepository _authenticationOIDCRepository;
+
+  DownloadMessageAsEMLInteractor(
+    this._emailRepository,
+    this._credentialRepository,
+    this._accountRepository,
+    this._authenticationOIDCRepository
+  );
+
+  Stream<Either<Failure, Success>> execute(
+    AccountId accountId,
+    String baseDownloadUrl,
+    Id blobId,
+    String subjectEmail
+  ) async* {
+    try {
+      yield Right<Failure, Success>(StartDownloadMessageAsEML());
+
+      final currentAccount = await _accountRepository.getCurrentAccount();
+      AccountRequest? accountRequest;
+
+      if (currentAccount.authenticationType == AuthenticationType.oidc) {
+        final tokenOidc = await _authenticationOIDCRepository.getStoredTokenOIDC(currentAccount.id);
+        accountRequest = AccountRequest.withOidc(token: tokenOidc);
+      } else {
+        final authenticationInfoCache = await _credentialRepository.getAuthenticationInfoStored();
+        accountRequest = AccountRequest.withBasic(
+          userName: UserName(authenticationInfoCache.username),
+          password: Password(authenticationInfoCache.password),
+        );
+      }
+
+      await _emailRepository.downloadMessageAsEML(
+        accountId,
+        baseDownloadUrl,
+        accountRequest,
+        blobId,
+        subjectEmail);
+
+      yield Right<Failure, Success>(DownloadMessageAsEMLSuccess());
+    } catch (exception) {
+      yield Left<Failure, Success>(DownloadMessageAsEMLFailure(exception));
+    }
+  }
+}