// * Service for handling GPS location functionality
// * Provides methods for:
// * - Location permission handling
// * - GPS service status checks
// * - Position determination
// * - Always-on location checks

import 'package:fforte/screens/addCam/exceptions/location_disabled_exception.dart';
import 'package:fforte/screens/addCam/exceptions/location_forbidden_exception.dart';
import 'package:fforte/screens/excursion/exceptions/need_always_location_exception.dart';
import 'package:geolocator/geolocator.dart';

/// Service class for handling all GPS location related functionality
class GeolocatorService {
  /// Determine the current device position with permission checks
  /// @param alwaysOnNeeded Whether the app needs always-on location permission
  /// @throws LocationDisabledException if location services are disabled
  /// @throws LocationForbiddenException if location permission is denied
  /// @throws NeedAlwaysLocation if always-on permission is needed but not granted
  /// @return Future[Position] The current GPS position
  static Future<Position> deteterminePosition({bool alwaysOnNeeded = false}) async {
    bool locationEnabled;
    LocationPermission permissionGiven;

    // Check if location services are enabled
    locationEnabled = await Geolocator.isLocationServiceEnabled();
    if (!locationEnabled) {
      throw LocationDisabledException();
    }

    // Check and request location permissions if needed
    permissionGiven = await Geolocator.checkPermission();
    if (permissionGiven == LocationPermission.denied) {
      permissionGiven = await Geolocator.requestPermission();
      if (permissionGiven == LocationPermission.denied || permissionGiven == LocationPermission.deniedForever) {
        throw LocationForbiddenException();
      }
    }

    // Check for always-on permission if required
    if (alwaysOnNeeded && permissionGiven != LocationPermission.always) {
      throw NeedAlwaysLocation();
    }
    
    return await Geolocator.getCurrentPosition();
  }

  /// Check if always-on location permission is enabled
  /// @return Future[bool] True if always-on permission is granted or location is disabled
  static Future<bool> alwaysPositionEnabled() async {
    LocationPermission permissionGiven = await Geolocator.checkPermission();
    bool locationEnabled = await Geolocator.isLocationServiceEnabled();

    if (permissionGiven == LocationPermission.always || !locationEnabled) {
      return true;
    } else {
      return false;
    }
  }
}