import 'dart:typed_data';

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

void main() {
  group('FirmwareFileSelectionService', () {
    test('prepares v1 metadata for selected .bin firmware', () async {
      final service = FirmwareFileSelectionService(
        filePicker: _FakeFirmwareFilePicker(
          selection: FirmwarePickerSelection(
            fileName: 'firmware.BIN',
            filePath: '/tmp/firmware.BIN',
            fileBytes: Uint8List.fromList(<int>[1, 2, 3, 4]),
          ),
        ),
        sessionIdGenerator: () => 0x1AB,
      );

      final result = await service.selectAndPrepareDfuV1();
      expect(result.isSuccess, isTrue);

      final firmware = result.firmware!;
      expect(firmware.fileName, 'firmware.BIN');
      expect(firmware.filePath, '/tmp/firmware.BIN');
      expect(firmware.fileBytes, <int>[1, 2, 3, 4]);
      expect(firmware.metadata.totalLength, 4);
      expect(firmware.metadata.crc32, 0xB63CFBCD);
      expect(firmware.metadata.sessionId, 0xAB);
      expect(firmware.metadata.flags, universalShifterDfuFlagNone);
    });

    test('returns canceled result when user dismisses picker', () async {
      final service = FirmwareFileSelectionService(
        filePicker: _FakeFirmwareFilePicker(selection: null),
      );

      final result = await service.selectAndPrepareDfuV1();

      expect(result.isSuccess, isFalse);
      expect(result.isCanceled, isTrue);
      expect(result.failure?.reason, FirmwareSelectionFailureReason.canceled);
    });

    test('rejects unsupported extension', () async {
      final service = FirmwareFileSelectionService(
        filePicker: _FakeFirmwareFilePicker(
          selection: FirmwarePickerSelection(
            fileName: 'firmware.hex',
            fileBytes: Uint8List.fromList(<int>[1]),
          ),
        ),
      );

      final result = await service.selectAndPrepareDfuV1();

      expect(result.isSuccess, isFalse);
      expect(result.failure?.reason,
          FirmwareSelectionFailureReason.unsupportedExtension);
    });

    test('rejects empty payload', () async {
      final service = FirmwareFileSelectionService(
        filePicker: _FakeFirmwareFilePicker(
          selection: FirmwarePickerSelection(
            fileName: 'firmware.bin',
            fileBytes: Uint8List(0),
          ),
        ),
      );

      final result = await service.selectAndPrepareDfuV1();

      expect(result.isSuccess, isFalse);
      expect(result.failure?.reason, FirmwareSelectionFailureReason.emptyFile);
    });

    test('generates session id per run', () async {
      var nextSession = 9;
      final service = FirmwareFileSelectionService(
        filePicker: _FakeFirmwareFilePicker(
          selection: FirmwarePickerSelection(
            fileName: 'firmware.bin',
            fileBytes: Uint8List.fromList(<int>[10]),
          ),
        ),
        sessionIdGenerator: () => nextSession++,
      );

      final first = await service.selectAndPrepareDfuV1();
      final second = await service.selectAndPrepareDfuV1();

      expect(first.firmware?.metadata.sessionId, 9);
      expect(second.firmware?.metadata.sessionId, 10);
    });

    test('maps picker read failure to explicit validation error', () async {
      final service = FirmwareFileSelectionService(
        filePicker: _FakeFirmwareFilePicker(
          selection: null,
          error: const FormatException('broken pick payload'),
        ),
      );

      final result = await service.selectAndPrepareDfuV1();

      expect(result.isSuccess, isFalse);
      expect(result.failure?.reason, FirmwareSelectionFailureReason.readFailed);
      expect(result.failure?.message, contains('broken pick payload'));
    });
  });
}

class _FakeFirmwareFilePicker implements FirmwareFilePicker {
  _FakeFirmwareFilePicker({
    required this.selection,
    this.error,
  });

  final FirmwarePickerSelection? selection;
  final Object? error;

  @override
  Future<FirmwarePickerSelection?> pickFirmwareFile() async {
    if (error != null) {
      throw error!;
    }
    return selection;
  }
}