import 'package:geolocator/geolocator.dart';
import 'package:permission_handler/permission_handler.dart';
import 'dart:math' as math;

class LocationService {
  static Future<bool> checkLocationPermission() async {
    LocationPermission permission = await Geolocator.checkPermission();
    if (permission == LocationPermission.denied) {
      permission = await Geolocator.requestPermission();
    }
    return permission == LocationPermission.whileInUse ||
        permission == LocationPermission.always;
  }

  static Future<bool> checkCameraPermission() async {
    PermissionStatus status = await Permission.camera.status;
    if (status.isDenied) {
      status = await Permission.camera.request();
    }
    return status.isGranted;
  }

  static Future<Position?> getCurrentPosition() async {
    try {
      bool hasPermission = await checkLocationPermission();
      if (!hasPermission) return null;

      return await Geolocator.getCurrentPosition(
        desiredAccuracy: LocationAccuracy.high,
      );
    } catch (e) {
      return null;
    }
  }

  static Stream<Position>? getPositionStream() async* {
    bool hasPermission = await checkLocationPermission();
    if (!hasPermission) {
      yield* Stream.empty();
      return;
    }

    const LocationSettings locationSettings = LocationSettings(
      accuracy: LocationAccuracy.high,
      distanceFilter: 1,
    );

    yield* Geolocator.getPositionStream(locationSettings: locationSettings);
  }

  static double calculateDistance(
    double lat1,
    double lon1,
    double lat2,
    double lon2,
  ) {
    return Geolocator.distanceBetween(lat1, lon1, lat2, lon2);
  }

  static bool isWithinRange(
    double currentLat,
    double currentLon,
    double targetLat,
    double targetLon, {
    double rangeInMeters = 50.0,
  }) {
    double distance = calculateDistance(
      currentLat,
      currentLon,
      targetLat,
      targetLon,
    );
    return distance <= rangeInMeters;
  }

  static double getBearing(
    double startLat,
    double startLng,
    double endLat,
    double endLng,
  ) {
    final startLatRad = startLat * (math.pi / 180);
    final startLngRad = startLng * (math.pi / 180);
    final endLatRad = endLat * (math.pi / 180);
    final endLngRad = endLng * (math.pi / 180);

    double dLng = endLngRad - startLngRad;

    double y = math.sin(dLng) * math.cos(endLatRad);
    double x =
        math.cos(startLatRad) * math.sin(endLatRad) -
        math.sin(startLatRad) * math.cos(endLatRad) * math.cos(dLng);

    double bearing = math.atan2(y, x);
    return (bearing * (180 / math.pi) + 360) % 360;
  }
}