import 'package:abawo_bt_app/model/shifter_types.dart';
import 'package:abawo_bt_app/service/dfu_protocol.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  group('BootloaderDfuProtocol CRC32', () {
    test('matches known vector', () {
      final crc = BootloaderDfuProtocol.crc32('123456789'.codeUnits);
      expect(crc, 0xCBF43926);
    });
  });

  group('BootloaderDfuProtocol control payload encoding', () {
    test('encodes START payload with exact 19-byte LE layout', () {
      final payload = BootloaderDfuProtocol.encodeStartPayload(
        const BootloaderDfuStartPayload(
          totalLength: 0x1234,
          imageCrc32: 0x89ABCDEF,
          appStart: universalShifterDfuAppStart,
          imageVersion: 0x10203040,
          sessionId: 0x22,
          flags: universalShifterDfuFlagNone,
        ),
      );

      expect(payload.length, 19);
      expect(payload, [
        universalShifterDfuOpcodeStart,
        0x34,
        0x12,
        0x00,
        0x00,
        0xEF,
        0xCD,
        0xAB,
        0x89,
        0x00,
        0x00,
        0x03,
        0x00,
        0x40,
        0x30,
        0x20,
        0x10,
        0x22,
        universalShifterDfuFlagNone,
      ]);
    });

    test('encodes FINISH, ABORT, and GET_STATUS payloads', () {
      expect(
        BootloaderDfuProtocol.encodeFinishPayload(0x12),
        [universalShifterDfuOpcodeFinish, 0x12],
      );
      expect(
        BootloaderDfuProtocol.encodeAbortPayload(0x34),
        [universalShifterDfuOpcodeAbort, 0x34],
      );
      expect(
        BootloaderDfuProtocol.encodeGetStatusPayload(),
        [universalShifterDfuOpcodeGetStatus],
      );
    });
  });

  group('BootloaderDfuProtocol data frame building', () {
    test('builds offset frames with payload CRC and variable final length', () {
      final image = List<int>.generate(60, (index) => index);
      final frames = BootloaderDfuProtocol.buildDataFrames(
        imageBytes: image,
        sessionId: 0x7A,
      );

      expect(frames.length, 2);

      expect(frames[0].sessionId, 0x7A);
      expect(frames[0].offset, 0);
      expect(frames[0].payloadLength,
          universalShifterBootloaderDfuMaxPayloadSizeBytes);
      expect(frames[0].bytes.length, universalShifterDfuFrameSizeBytes);
      expect(frames[0].bytes[0], 0x7A);
      expect(frames[0].bytes.sublist(1, 5), [0, 0, 0, 0]);
      expect(
        frames[0].bytes.sublist(5, 9),
        _leU32Bytes(BootloaderDfuProtocol.crc32(image.sublist(0, 55))),
      );
      expect(frames[0].bytes.sublist(9), image.sublist(0, 55));

      expect(frames[1].offset, 55);
      expect(frames[1].payloadLength, 5);
      expect(frames[1].bytes.length, 14);
      expect(frames[1].bytes.sublist(1, 5), [55, 0, 0, 0]);
      expect(frames[1].bytes.sublist(9), image.sublist(55));
    });

    test('uses caller supplied payload size for low-MTU links', () {
      final image = List<int>.generate(15, (index) => index);
      final frames = BootloaderDfuProtocol.buildDataFrames(
        imageBytes: image,
        sessionId: 0x01,
        payloadSize: 4,
      );

      expect(frames.map((frame) => frame.payloadLength), [4, 4, 4, 3]);
      expect(frames.map((frame) => frame.offset), [0, 4, 8, 12]);
    });

    test('calculates safe payload size from negotiated MTU', () {
      expect(
        BootloaderDfuProtocol.maxPayloadSizeForMtu(64),
        universalShifterBootloaderDfuMaxPayloadSizeBytes - 3,
      );
      expect(BootloaderDfuProtocol.maxPayloadSizeForMtu(23), 11);
      expect(BootloaderDfuProtocol.maxPayloadSizeForMtu(12), 0);
      expect(
        BootloaderDfuProtocol.maxPayloadSizeForMtu(128),
        universalShifterBootloaderDfuMaxPayloadSizeBytes,
      );
    });
  });

  group('BootloaderDfuProtocol status parsing', () {
    test('parses bootloader status payload', () {
      final status = BootloaderDfuProtocol.parseStatusPayload(
        [0x00, 0x22, 0x78, 0x56, 0x34, 0x12],
      );

      expect(status.code, DfuBootloaderStatusCode.ok);
      expect(status.rawCode, 0x00);
      expect(status.sessionId, 0x22);
      expect(status.expectedOffset, 0x12345678);
      expect(status.isOk, isTrue);
    });

    test('preserves unknown status codes', () {
      final status = BootloaderDfuProtocol.parseStatusPayload(
        [0xFE, 0x00, 0x00, 0x00, 0x00, 0x00],
      );

      expect(status.code, DfuBootloaderStatusCode.unknown);
      expect(status.rawCode, 0xFE);
    });

    test('rejects malformed status payloads', () {
      expect(
        () => BootloaderDfuProtocol.parseStatusPayload(const [0, 1]),
        throwsFormatException,
      );
    });
  });
}

List<int> _leU32Bytes(int value) {
  return [
    value & 0xFF,
    (value >> 8) & 0xFF,
    (value >> 16) & 0xFF,
    (value >> 24) & 0xFF,
  ];
}