import 'dart:async';
import 'dart:io';

import 'package:flutter/foundation.dart';
import 'package:qrscanner/services/scan_launch_service.dart';

typedef HardwareScanCallback = void Function(String rawValue);

/// Integración con el escáner físico Honeywell vía Intent API nativa (EDA51).
class HardwareScannerService {
  HardwareScannerService._();

  static final HardwareScannerService instance = HardwareScannerService._();

  final _scanLaunch = ScanLaunchService.instance;

  HardwareScanCallback? _onScan;
  void Function(Exception error)? _onError;
  StreamSubscription<String>? _scanSubscription;
  bool _active = false;

  bool get isActive => _active;

  static Future<bool> isAvailable() => instance._scanLaunch.isSupported();

  Future<bool> activate({
    required HardwareScanCallback onScan,
    void Function(Exception error)? onError,
  }) async {
    if (kIsWeb || !Platform.isAndroid) return false;

    _onScan = onScan;
    _onError = onError;

    await _scanLaunch.claimScanner();
    await _scanSubscription?.cancel();
    _scanSubscription = _scanLaunch.scanStream.listen(
      (code) => _onScan?.call(code),
      onError: (Object error) => _onError?.call(Exception(error.toString())),
    );

    _active = true;
    return _scanLaunch.isSupported();
  }

  Future<void> pause() async {
    _active = false;
  }

  Future<void> deactivate() async {
    await _scanSubscription?.cancel();
    _scanSubscription = null;
    _onScan = null;
    _onError = null;
    _active = false;
  }

  Future<void> ensureStopped() async {
    await deactivate();
    await _scanLaunch.releaseScanner();
  }
}