Change mapping and bug fixes

lib/core/model/optional_range.dart

@@ -0,0 +1,54 @@
+import 'package:dart_mappable/dart_mappable.dart';
+import 'package:dartx/dartx.dart';
+import 'package:hiddify/core/localization/translations.dart';
+
+part 'optional_range.mapper.dart';
+
+@MappableClass()
+class OptionalRange with OptionalRangeMappable {
+  const OptionalRange({this.min, this.max});
+
+  final int? min;
+  final int? max;
+
+  String format() => [min, max].whereNotNull().join("-");
+  String present(TranslationsEn t) =>
+      format().isEmpty ? t.general.notSet : format();
+
+  factory OptionalRange._fromString(
+    String input, {
+    bool allowEmpty = true,
+  }) =>
+      switch (input.split("-")) {
+        [final String val] when val.isEmpty && allowEmpty =>
+          const OptionalRange(),
+        [final String min] => OptionalRange(min: int.parse(min)),
+        [final String min, final String max] => OptionalRange(
+            min: int.parse(min),
+            max: int.parse(max),
+          ),
+        _ => throw Exception("Invalid range: $input"),
+      };
+
+  static OptionalRange? tryParse(
+    String input, {
+    bool allowEmpty = false,
+  }) {
+    try {
+      return OptionalRange._fromString(input);
+    } catch (_) {
+      return null;
+    }
+  }
+}
+
+class OptionalRangeJsonMapper extends SimpleMapper<OptionalRange> {
+  const OptionalRangeJsonMapper();
+
+  @override
+  OptionalRange decode(dynamic value) =>
+      OptionalRange._fromString(value as String);
+
+  @override
+  dynamic encode(OptionalRange self) => self.format();
+}