TF-3294 Fix BLUE-BAR mail to attendees duplicated recipients

model/lib/extensions/list_email_address_extension.dart

@@ -69,6 +69,15 @@ extension SetEmailAddressExtension on Set<EmailAddress>? {
 extension ListEmailAddressExtension on List<EmailAddress> {
   Set<String> asSetAddress() => map((emailAddress) => emailAddress.emailAddress).toSet();
 
+  List<EmailAddress> removeInvalidEmails(String username) {
+    final Set<String> seenEmails = {};
+    return where((email) {
+      if (email.emailAddress.isEmpty) return false;
+      if (email.emailAddress == username) return false;
+      return seenEmails.add(email.emailAddress);
+    }).toList();
+  }
+
   List<EmailAddress> withoutMe(String? userName) {
     if (userName == null) return this;
 

model/test/extensions/list_email_address_extension_test.dart

@@ -1,5 +1,6 @@
 import 'package:flutter_test/flutter_test.dart';
 import 'package:jmap_dart_client/jmap/mail/email/email_address.dart';
+import 'package:model/extensions/email_address_extension.dart';
 import 'package:model/extensions/list_email_address_extension.dart';
 
 void main() {
@@ -43,4 +44,69 @@ void main() {
       expect(result, 'John Doe <john@example.com>, Jane Smith <jane@example.com>');
     });
   });
+
+  group('ListEmailAddressExtension::removeInvalidEmails::test', () {
+    test('SHOULD remove email addresses that are empty', () {
+      final emails = [
+        EmailAddress('Alice', 'alice@example.com'),
+        EmailAddress('Bob', ''),
+        EmailAddress('Charlie', 'charlie@example.com'),
+      ];
+
+      final validEmails = emails.removeInvalidEmails('bob@example.com');
+
+      expect(validEmails.length, 2);
+      expect(validEmails[0].emailAddress, 'alice@example.com');
+      expect(validEmails[1].emailAddress, 'charlie@example.com');
+    });
+
+    test('SHOULD remove email addresses that match the provided username', () {
+      final emails = [
+        EmailAddress('Alice', 'alice@example.com'),
+        EmailAddress('Bob', 'bob@example.com'),
+        EmailAddress('Charlie', 'charlie@example.com'),
+      ];
+
+      final validEmails = emails.removeInvalidEmails('bob@example.com');
+
+      expect(validEmails.length, 2);
+      expect(validEmails[0].emailAddress, 'alice@example.com');
+      expect(validEmails[1].emailAddress, 'charlie@example.com');
+    });
+
+    test('SHOULD remove duplicate email addresses, keeping only the first occurrence', () {
+      final emails = [
+        EmailAddress('Alice', 'alice@example.com'),
+        EmailAddress('Bob', 'bob@example.com'),
+        EmailAddress('Charlie', 'alice@example.com'),
+        EmailAddress('David', 'david@example.com'),
+      ];
+
+      final validEmails = emails.removeInvalidEmails('bob@example.com');
+
+      expect(validEmails.length, 2);
+      expect(validEmails[0].emailAddress, 'alice@example.com');
+      expect(validEmails[1].emailAddress, 'david@example.com');
+    });
+
+    test('SHOULD return an empty list if all email addresses are invalid', () {
+      final emails = [
+        EmailAddress('Alice', ''),
+        EmailAddress('Bob', 'bob@example.com'),
+        EmailAddress('Charlie', 'bob@example.com'),
+      ];
+
+      final validEmails = emails.removeInvalidEmails('bob@example.com');
+
+      expect(validEmails.isEmpty, true);
+    });
+
+    test('SHOULD return an empty list for an empty input list', () {
+      final emails = <EmailAddress>[];
+
+      final validEmails = emails.removeInvalidEmails('bob@example.com');
+
+      expect(validEmails.isEmpty, true);
+    });
+  });
 }