import 'dart:typed_data';
import 'package:flutter_test/flutter_test.dart';
import 'package:hvbt_dash/core/protocol/neg8.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 2..3, raw stream is display RPM + 256
  final rpmRaw = rpm + 256;
  frame[2] = (rpmRaw >> 8) & 0xFF;
  frame[3] = rpmRaw & 0xFF;
  // VSS: bytes 5..6 little-endian
  frame[5] = vss & 0xFF;
  frame[6] = (vss >> 8) & 0xFF;
  // MAP: bytes 7..8 little-endian
  frame[7] = mapRaw & 0xFF;
  frame[8] = (mapRaw >> 8) & 0xFF;
  // TPS: byte 9
  frame[9] = tps;
  // INJ: bytes 10..11 little-endian
  frame[10] = inj & 0xFF;
  frame[11] = (inj >> 8) & 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 0x24
  frame[0x24] = 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 = 144256 / 1000 = 144.256 mph
      final frame = _buildS300Frame(vss: 1000);
      final state = parseS300(frame);
      expect(state.vss, closeTo(144.26, 0.01));
    });

    test('parses MAP as SManager-style psi', () {
      // mapRaw = 1148 -> 114.8 kPa absolute -> about 1.6 psi displayed
      final frame = _buildS300Frame(mapRaw: 1148);
      final state = parseS300(frame);
      expect(state.map, closeTo(1.6, 0.01));
    });

    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=134 -> approximately 51%
      final frame = _buildS300Frame(tps: 134);
      final state = parseS300(frame);
      expect(state.tps, closeTo(50.93, 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 = 164 -> 49.0°
      final frame = _buildS300Frame(ign: 164);
      final state = parseS300(frame);
      expect(state.ign, equals(49.0));
    });

    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);
    });

    test('can parse bad checksum frame when validation is disabled', () {
      final frame = _buildS300Frame(rpm: 1000);
      frame[127] = 0x00; // corrupt checksum
      final state = parseS300(frame, validateChecksum: false);
      expect(state.rpm, equals(1000.0));
    });

    test('detects known S300 prefix signature', () {
      final frame = Uint8List(128);
      final signature = [
        0x1B,
        0x00,
        0x14,
        0x00,
        0x00,
        0xFF,
        0xFF,
        0xF2,
        0x03,
        0x18,
        0x00,
        0x00,
        0x10,
        0x00,
        0x00,
        0x00,
        0xC4,
      ];
      for (var i = 0; i < signature.length; i++) {
        frame[i] = signature[i];
      }
      frame[127] = calculateNeg8(frame.sublist(0, 127));

      expect(isS300PlaceholderFrame(frame), isTrue);
    });

    test('uses calibrated tail payload RPM for S300 Bluetooth prefix frames',
        () {
      final frame = Uint8List(128);
      final prefix = [
        0x1B,
        0x00,
        0x14,
        0x00,
        0x00,
        0xFF,
        0xFF,
        0xF2,
        0x03,
        0x18,
        0x00,
        0x00,
        0x10,
        0x00,
        0x00,
        0x00,
        0xC4,
      ];
      for (var i = 0; i < prefix.length; i++) {
        frame[i] = prefix[i];
      }
      frame[82] = 0x32;
      frame[83] = 0x0C;
      frame[127] = calculateNeg8(frame.sublist(0, 127));

      final state = parseS300(frame);
      expect(state.rpm, equals(2033.0));
    });
  });
}