BirthdayCalendar logic to filter already added contacts

Author: TomerPacific

lib/page/settings_page/settings_screen_manager.dart

@@ -105,9 +105,22 @@ class SettingsScreenManager extends ChangeNotifier {
       return;
     }
 
+    contacts = await _filterAlreadyImportedContacts(contacts);
+
+    if (contacts.length == 0) {
+      _snackbarService.showSnackbarWithMessage(context, noContactsFoundMsg);
+      return;
+    }
+
     _handleAddingBirthdaysToContacts(context, contacts);
   }
 
+  Future<List<Contact>> _filterAlreadyImportedContacts(List<Contact> contacts) async {
+    List<String> namesOfPeopleWithBirthdays = await _storageService.getAllBirthdays();
+    List<Contact> filtered = contacts.where((contact) => !namesOfPeopleWithBirthdays.contains(contact.displayName)).toList();
+    return filtered;
+  }
+
   void addContactToCalendar(UserBirthday contact) {
     _bcContactsService.addContactToCalendar(contact);
   }