import 'package:flutter/services.dart';

class HHmmInputFormatter extends TextInputFormatter {
  const HHmmInputFormatter();

  @override
  TextEditingValue formatEditUpdate(TextEditingValue oldValue, TextEditingValue newValue) {
    String digits = newValue.text.replaceAll(RegExp(r'[^0-9]'), '');
    if (digits.isEmpty) {
      return const TextEditingValue(text: '', selection: TextSelection.collapsed(offset: 0));
    }
    if (digits.length > 4) digits = digits.substring(0, 4);

    String text;
    if (digits.length <= 2) {
      text = digits;
    } else {
      final hh = digits.substring(0, 2);
      final mm = digits.substring(2);
      text = '$hh:$mm'; // ← Interpolation statt + ':' +
    }

    final offset = text.length;
    return TextEditingValue(text: text, selection: TextSelection.collapsed(offset: offset));
  }
}