import 'dart:typed_data';
import 'package:flutter_test/flutter_test.dart';
import 'package:hvbt_dash/core/protocol/neg8.dart';

void main() {
  group('NEG8 checksum', () {
    test('S300 request header [0x1B, 0x00] produces 0xE5', () {
      // NEG8 of [0x1B, 0x00] = (0 - 0x1B - 0x00) & 0xFF = 0xE5
      final buf = Uint8List.fromList([0x1B, 0x00]);
      expect(calculateNeg8(buf), equals(0xE5));
    });

    test('KPro request header [0x1B, 0x01] produces 0xE4', () {
      final buf = Uint8List.fromList([0x1B, 0x01]);
      expect(calculateNeg8(buf), equals(0xE4));
    });

    test('validateFrame passes for correctly checksummed frame', () {
      // Build a 4-byte frame where last byte = NEG8 of first 3
      final data = Uint8List.fromList([0x1B, 0x00, 0x00, 0xE5]);
      expect(validateFrame(data), isTrue);
    });

    test('validateFrame fails for corrupted frame', () {
      final data = Uint8List.fromList([0x1B, 0x00, 0x00, 0xFF]);
      expect(validateFrame(data), isFalse);
    });

    test('validateFrame returns false for empty frame', () {
      expect(validateFrame(Uint8List(0)), isFalse);
    });

    test('single byte 0x00 validates as [0x00, 0x00]', () {
      // NEG8([0x00]) = 0x00, so frame [0x00, 0x00] should pass
      expect(validateFrame(Uint8List.fromList([0x00, 0x00])), isTrue);
    });
  });
}