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

/// Builds a zeroed 128-byte KPro frame and stamps the NEG8 checksum at byte 127.
Uint8List _buildKProFrame({
  int rpm = 0,
  int vss = 0,
  int tps = 0,
  int map1 = 0,
  int map2 = 0,
  int ign = 0,
  int ect = 0x80, // tempXlt[0x80]=73 → 113°C
  int bat = 0,
  int sw1 = 0,
  int sw2 = 0,
  int krtrd = 0,
}) {
  final frame = Uint8List(128);
  // Header
  frame[0] = 0x1B;
  frame[1] = 0x01;
  // RPM: bytes 2..3
  frame[2] = (rpm >> 8) & 0xFF;
  frame[3] = rpm & 0xFF;
  // VSS: byte 4
  frame[4] = vss & 0xFF;
  // TPS: byte 5
  frame[5] = tps & 0xFF;
  // MAP1: byte 6
  frame[6] = map1 & 0xFF;
  // MAP2: bytes 33..34
  frame[33] = (map2 >> 8) & 0xFF;
  frame[34] = map2 & 0xFF;
  // IGN: byte 13
  frame[13] = ign;
  // KRtrd: byte 21
  frame[21] = krtrd;
  // SW1: byte 31, SW2: byte 32
  frame[31] = sw1;
  frame[32] = sw2;
  // ECT: byte 49
  frame[49] = ect;
  // BAT: byte 52
  frame[52] = bat;

  // Stamp NEG8 checksum at byte 127
  int neg8 = 0;
  for (int i = 0; i < 127; i++) {
    neg8 = (neg8 - frame[i]) & 0xFF;
  }
  frame[127] = neg8;
  return frame;
}

void main() {
  group('KPro parser', () {
    test('parses RPM = raw / 4', () {
      // rpm raw = 4000 → 1000.0 revs
      final frame = _buildKProFrame(rpm: 4000);
      final state = parseKPro(frame);
      expect(state.rpm, equals(1000.0));
    });

    test('parses VSS directly', () {
      final frame = _buildKProFrame(vss: 120);
      final state = parseKPro(frame);
      expect(state.vss, equals(120.0));
    });

    test('parses TPS directly', () {
      final frame = _buildKProFrame(tps: 75);
      final state = parseKPro(frame);
      expect(state.tps, equals(75.0));
    });

    test('parses MAP from MAP1 when MAP2 = 0', () {
      final frame = _buildKProFrame(map1: 100, map2: 0);
      final state = parseKPro(frame);
      expect(state.map, equals(100.0));
    });

    test('parses MAP from MAP2 / 10 when MAP2 != 0', () {
      // map2 raw = 1000 → 100.0 kPa
      final frame = _buildKProFrame(map1: 50, map2: 1000);
      final state = parseKPro(frame);
      expect(state.map, equals(100.0));
    });

    test('parses ECT using temp lookup table', () {
      // ect raw = 0x80 = 128 → tempXlt[128]=73 → 113°C
      final frame = _buildKProFrame(ect: 0x80);
      final state = parseKPro(frame);
      expect(state.ect, equals((tempXlt[0x80] + 40).toDouble()));
    });

    test('parses BAT = raw / 10', () {
      // bat raw = 130 → 13.0 V
      final frame = _buildKProFrame(bat: 130);
      final state = parseKPro(frame);
      expect(state.bat, equals(13.0));
    });

    test('MIL flag from SW2 bit2', () {
      final frame = _buildKProFrame(sw2: 0x04); // bit2
      final state = parseKPro(frame);
      expect(state.mil, isTrue);
    });

    test('knock flag when krtrd > 0', () {
      final frame = _buildKProFrame(krtrd: 3);
      final state = parseKPro(frame);
      expect(state.knock, isTrue);
    });

    test('errBytes has 18 entries', () {
      final frame = _buildKProFrame();
      final state = parseKPro(frame);
      expect(state.errBytes.length, equals(18));
    });

    test('throws on wrong frame length', () {
      expect(() => parseKPro(Uint8List(64)), throwsArgumentError);
    });

    test('throws on bad checksum', () {
      final frame = _buildKProFrame(rpm: 4000);
      frame[127] = 0x00; // corrupt
      expect(() => parseKPro(frame), throwsArgumentError);
    });
  });
}