import 'package:flutter_test/flutter_test.dart';
import 'package:fuel_tax_tracker/services/vin_parser.dart';

void main() {
  group('VinParser', () {
    test('parses a bare 17-character VIN', () {
      const text = '''
        VEHICLE IDENTIFICATION NUMBER
        1HGCM82633A004352
        MFD BY HONDA MFG CO
      ''';

      expect(VinParser.parse(text), '1HGCM82633A004352');
    });

    test('prefers a "VIN:" labeled match over another candidate elsewhere', () {
      const text = '''
        PART NO 4F2CZ58899BA12345
        VIN: 1HGCM82633A004352
      ''';

      expect(VinParser.parse(text), '1HGCM82633A004352');
    });

    test('normalizes to uppercase', () {
      expect(VinParser.parse('vin: 1hgcm82633a004352'), '1HGCM82633A004352');
    });

    test('does not match a run containing I, O, or Q (never valid in a real VIN)', () {
      // Same length (17) but contains an "O" partway through, so no
      // 17-character eligible-charset run exists anywhere in it.
      expect(VinParser.parse('1HGCM82633AOO4352'), isNull);
    });

    test('does not match a 16-character (too short) run', () {
      expect(VinParser.parse('1HGCM82633A00435'), isNull);
    });

    test('does not match an 18-character (too long) run', () {
      expect(VinParser.parse('1HGCM82633A0043521'), isNull);
    });

    test('returns null when nothing matches', () {
      expect(VinParser.parse('THANK YOU FOR YOUR PURCHASE'), isNull);
    });
  });
}