import 'package:geolocator/geolocator.dart';
import 'package:geocoding/geocoding.dart' as geocoding;
import 'package:hive_flutter/hive_flutter.dart';
import '../local/hive_boxes.dart';
import '../local/models/app_settings.dart';

/// Location service with GPS + fallback to last known location.
class LocationService {
  LocationService._();
  static final LocationService instance = LocationService._();

  /// Request permission and get current GPS location.
  Future<Position?> getCurrentLocation() async {
    bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
    if (!serviceEnabled) return null;

    LocationPermission permission = await Geolocator.checkPermission();
    if (permission == LocationPermission.denied) {
      permission = await Geolocator.requestPermission();
      if (permission == LocationPermission.denied) return null;
    }

    if (permission == LocationPermission.deniedForever) return null;

    try {
      final position = await Geolocator.getCurrentPosition(
        locationSettings: const LocationSettings(
          accuracy: LocationAccuracy.medium,
          timeLimit: Duration(seconds: 10),
        ),
      );

      // Save to settings for fallback
      await _saveLastKnown(position.latitude, position.longitude);
      return position;
    } catch (_) {
      return null;
    }
  }

  /// Get last known location from Hive settings.
  ({double lat, double lng, String? cityName})? getLastKnownLocation() {
    final settingsBox = Hive.box<AppSettings>(HiveBoxes.settings);
    final settings = settingsBox.get('default');
    if (settings?.lastLat != null && settings?.lastLng != null) {
      return (
        lat: settings!.lastLat!,
        lng: settings.lastLng!,
        cityName: settings.lastCityName,
      );
    }
    return null;
  }

  /// Reverse geocode to get city name from coordinates.
  Future<String> getCityName(double lat, double lng) async {
    try {
      final placemarks = await geocoding.placemarkFromCoordinates(lat, lng);
      if (placemarks.isNotEmpty) {
        final place = placemarks.first;
        final city = place.locality ?? place.subAdministrativeArea ?? 'Unknown';
        final country = place.country ?? '';
        return '$city, $country';
      }
    } catch (_) {
      // Geocoding may fail offline — return coords
    }
    return '${lat.toStringAsFixed(2)}, ${lng.toStringAsFixed(2)}';
  }

  /// Save last known position to Hive.
  Future<void> _saveLastKnown(double lat, double lng) async {
    final settingsBox = Hive.box<AppSettings>(HiveBoxes.settings);
    final settings = settingsBox.get('default');
    if (settings != null) {
      settings.lastLat = lat;
      settings.lastLng = lng;
      try {
        settings.lastCityName = await getCityName(lat, lng);
      } catch (_) {
        // Ignore geocoding errors
      }
      await settings.save();
    }
  }
}