import 'dart:typed_data';
import 'package:flutter_test/flutter_test.dart';
import 'package:hvbt_dash/core/protocol/s300_parser.dart';
import 'package:hvbt_dash/core/protocol/temp_table.dart';

/// Builds a zeroed 128-byte S300 frame and stamps the NEG8 checksum at byte 127.
Uint8List _buildS300Frame({
  int rpm = 0,
  int vss = 0,
  int mapRaw = 0,
  int tps = 0,
  int inj = 0,
  int ign = 0,
  int ect = 0x80, // tempXlt[0x80]=73 → 73+40=113°C
  int bat = 0,
  int sw1 = 0,
  int sw2 = 0,
  int sw3 = 0,
  int krtrd = 0,
}) {
  final frame = Uint8List(128);
  // Header
  frame[0] = 0x1B;
  frame[1] = 0x00;
  // RPM: bytes 3..4
  frame[3] = (rpm >> 8) & 0xFF;
  frame[4] = rpm & 0xFF;
  // VSS: bytes 5..6
  frame[5] = (vss >> 8) & 0xFF;
  frame[6] = vss & 0xFF;
  // MAP: bytes 7..8
  frame[7] = (mapRaw >> 8) & 0xFF;
  frame[8] = mapRaw & 0xFF;
  // TPS: byte 9
  frame[9] = tps;
  // INJ: bytes 10..11
  frame[10] = (inj >> 8) & 0xFF;
  frame[11] = inj & 0xFF;
  // IGN: byte 12
  frame[12] = ign;
  // KRtrd: byte 13
  frame[13] = krtrd;
  // SW bitmaps
  frame[0x11] = sw1;
  frame[0x12] = sw2;
  frame[0x13] = sw3;
  // ECT: byte 0x2D
  frame[0x2D] = ect;
  // BAT: byte 0x30
  frame[0x30] = 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('S300 parser', () {
    test('parses RPM correctly', () {
      // RPM raw = 3000
      final frame = _buildS300Frame(rpm: 3000);
      final state = parseS300(frame);
      expect(state.rpm, equals(3000.0));
    });

    test('parses VSS = 0 when raw < 893', () {
      final frame = _buildS300Frame(vss: 500);
      final state = parseS300(frame);
      expect(state.vss, equals(0.0));
    });

    test('parses VSS correctly when raw >= 893', () {
      // vss = 228480 / 1000 = 228.48 km/h
      final frame = _buildS300Frame(vss: 1000);
      final state = parseS300(frame);
      expect(state.vss, closeTo(228.48, 0.01));
    });

    test('parses MAP = raw / 10', () {
      // mapRaw = 1000 → 100.0 kPa
      final frame = _buildS300Frame(mapRaw: 1000);
      final state = parseS300(frame);
      expect(state.map, equals(100.0));
    });

    test('parses TPS = 0 when raw < 25', () {
      final frame = _buildS300Frame(tps: 10);
      final state = parseS300(frame);
      expect(state.tps, equals(0.0));
    });

    test('parses TPS correctly when raw >= 25', () {
      // tps raw=46 → 46*51/46 = 51.0
      final frame = _buildS300Frame(tps: 46);
      final state = parseS300(frame);
      expect(state.tps, closeTo(51.0, 0.01));
    });

    test('parses ECT using temp lookup table', () {
      // ect raw = 0x80 = 128 → tempXlt[128]=73 → 73+40=113°C
      final frame = _buildS300Frame(ect: 0x80);
      final state = parseS300(frame);
      expect(state.ect, equals((tempXlt[0x80] + 40).toDouble()));
    });

    test('parses BAT = raw * 26 / 270', () {
      // bat raw = 135 → 135*26/270 = 13.0 V
      final frame = _buildS300Frame(bat: 135);
      final state = parseS300(frame);
      expect(state.bat, closeTo(13.0, 0.01));
    });

    test('IGN decode: (raw + 120) / 2', () {
      // ign raw = 20 → (20+120)/2 = 70.0°
      final frame = _buildS300Frame(ign: 20);
      final state = parseS300(frame);
      expect(state.ign, equals(70.0));
    });

    test('MIL flag set from SW2 bit5', () {
      final frame = _buildS300Frame(sw2: 0x20); // bit5 set
      final state = parseS300(frame);
      expect(state.mil, isTrue);
    });

    test('knock flag set when krtrd > 0', () {
      final frame = _buildS300Frame(krtrd: 5);
      final state = parseS300(frame);
      expect(state.knock, isTrue);
    });

    test('knock flag clear when krtrd = 0', () {
      final frame = _buildS300Frame(krtrd: 0);
      final state = parseS300(frame);
      expect(state.knock, isFalse);
    });

    test('throws on wrong frame length', () {
      expect(
        () => parseS300(Uint8List(64)),
        throwsArgumentError,
      );
    });

    test('throws on bad checksum', () {
      final frame = _buildS300Frame(rpm: 1000);
      frame[127] = 0x00; // corrupt checksum
      expect(() => parseS300(frame), throwsArgumentError);
    });
  });
}