import 'package:geolocator/geolocator.dart';

class LocationResult {
  final String latitude;
  final String longitude;

  LocationResult({
    required this.latitude,
    required this.longitude,
  });

  factory LocationResult.fromPosition(Position p) {
    return LocationResult(
      latitude: p.latitude.toString(),
      longitude: p.longitude.toString(),
    );
  }

  double? get latitudeAsDouble => double.tryParse(latitude);
  double? get longitudeAsDouble => double.tryParse(longitude);

  @override
  String toString() => 'LocationResult(latitude: $latitude, longitude: $longitude)';
}

class LocationException implements Exception {
  final String message;
  LocationException(this.message);
  @override
  String toString() => message;
}

/// 统一处理定位权限与获取经纬度（字符串形式）
class LocationService {
  /// 获取当前经纬度（字符串形式），成功返回 LocationResult，失败抛出 LocationException
  static Future<LocationResult> getCurrentLocation({
    Duration timeout = const Duration(seconds: 10),
  }) async {
    // 检查定位服务是否开启
    bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
    if (!serviceEnabled) {
      await Geolocator.openLocationSettings();
      throw LocationException('定位服务未开启，请打开设备定位后重试');
    }

    // 检查/请求权限
    LocationPermission permission = await Geolocator.checkPermission();
    if (permission == LocationPermission.denied) {
      permission = await Geolocator.requestPermission();
      if (permission == LocationPermission.denied) {
        throw LocationException('定位权限被拒绝');
      }
    }

    if (permission == LocationPermission.deniedForever) {
      throw LocationException(
        '定位权限被永久拒绝，请去系统设置中为应用打开定位权限',
      );
    }

    // 获取位置（带超时）
    try {
      final position = await Geolocator
          .getCurrentPosition(desiredAccuracy: LocationAccuracy.high)
          .timeout(timeout);
      return LocationResult.fromPosition(position);
    } on Exception catch (e) {
      throw LocationException('获取位置失败: ${e.toString()}');
    }
  }
}