TF-825 Download email as EML file (#2854)

model/lib/email/attachment.dart

@@ -44,8 +44,8 @@ class Attachment with EquatableMixin {
     final downloadUri = downloadUriTemplate.expand({
       'accountId' : accountId.id.value,
       'blobId' : '${blobId?.value}',
-      'name' : '$name',
-      'type' : '${type?.mimeType}',
+      'name' : name ?? '',
+      'type' : type?.mimeType ?? '',
     });
     return Uri.decodeFull(downloadUri);
   }

model/lib/email/email_action_type.dart

@@ -27,5 +27,6 @@ enum EmailActionType {
   unsubscribe,
   composeFromUnsubscribeMailtoLink,
   archiveMessage,
-  printAll
+  printAll,
+  downloadMessageAsEML
 }

model/lib/email/email_property.dart

@@ -1,6 +1,7 @@
 
 class EmailProperty {
   static const String id = 'id';
+  static const String blobId = 'blobId';
   static const String keywords = 'keywords';
   static const String size = 'size';
   static const String receivedAt = 'receivedAt';

model/lib/email/eml_attachment.dart

@@ -0,0 +1,15 @@
+
+import 'package:model/email/attachment.dart';
+
+class EMLAttachment extends Attachment {
+
+  EMLAttachment({
+    super.partId,
+    super.blobId,
+    super.size,
+    super.name,
+    super.type,
+    super.cid,
+    super.disposition,
+  });
+}

model/lib/email/presentation_email.dart

@@ -1,6 +1,7 @@
 
 import 'package:core/presentation/extensions/string_extension.dart';
 import 'package:equatable/equatable.dart';
+import 'package:jmap_dart_client/jmap/core/id.dart';
 import 'package:jmap_dart_client/jmap/core/unsigned_int.dart';
 import 'package:jmap_dart_client/jmap/core/utc_date.dart';
 import 'package:jmap_dart_client/jmap/mail/email/email.dart';
@@ -21,6 +22,7 @@ import 'package:model/mailbox/select_mode.dart';
 class PresentationEmail with EquatableMixin {
 
   final EmailId? id;
+  final Id? blobId;
   final Map<KeyWordIdentifier, bool>? keywords;
   final UnsignedInt? size;
   final UTCDate? receivedAt;
@@ -44,6 +46,7 @@ class PresentationEmail with EquatableMixin {
 
   PresentationEmail({
     this.id,
+    this.blobId,
     this.keywords,
     this.size,
     this.receivedAt,
@@ -142,6 +145,7 @@ class PresentationEmail with EquatableMixin {
   @override
   List<Object?> get props => [
     id,
+    blobId,
     keywords,
     size,
     receivedAt,