import 'package:collection/collection.dart';

part 'main.g.dart';

@RealmModel()
class _Item {
  @MapTo('_id')
  @PrimaryKey()
  late ObjectId id;
  late List<_FieldValue> fieldValues = const [];
}

@RealmModel()
class _FieldValue {
  late _FieldProperty? fieldProperty;
  late String? textValue;
}

@RealmModel()
class _FieldProperty {
  @MapTo('_id')
  @PrimaryKey()
  late ObjectId id;

  String name = "";
}

void main(List<String> arguments) {
  final realm = Realm(Configuration.local([
    FieldValue.schema,
    FieldProperty.schema,
    Item.schema,
  ]));

  final field = FieldProperty(ObjectId(), name: "text");
  final unsortedItems = [
    Item(ObjectId(), fieldValues: [FieldValue(ObjectId(), textValue: "a", fieldProperty: field)]),
    Item(ObjectId(), fieldValues: [FieldValue(ObjectId(), textValue: "d", fieldProperty: field)]),
    Item(ObjectId(), fieldValues: [FieldValue(ObjectId(), textValue: "c", fieldProperty: field)]),
    Item(ObjectId(), fieldValues: [FieldValue(ObjectId(),                 fieldProperty: field)]),
    Item(ObjectId(), fieldValues: [FieldValue(ObjectId(), textValue: "b", fieldProperty: field)])
  ];
  realm.write(() {
    realm.add(field);
    realm.addAll(unsortedItems);
  });

  var unsortedTextValues = unsortedItems
      .map((item) => (item.fieldValues
              .firstWhereOrNull((element) => element.fieldProperty == field)
              ?.textValue ??
          ""))
      .join(", ");

  print(unsortedTextValues); // a, d, c, , b

  // Sort items
  var sortedItems = unsortedItems.sorted((a, b) => (a.fieldValues
              .firstWhereOrNull((element) => element.fieldProperty == field)
              ?.textValue ??
          "")
      .compareTo((b.fieldValues.firstWhereOrNull(
              (element) => element.fieldProperty == field))?.textValue ??
          ""));

  var sortedTextValues = sortedItems
      .map((item) => (item.fieldValues
              .firstWhereOrNull((element) => element.fieldProperty == field)
              ?.textValue ??
          ""))
      .join(", ");

  print(sortedTextValues); //  , a, b, c, d

  Realm.shutdown();
}