import 'package:flutter/material.dart';
import 'package:geocoding/geocoding.dart';
import 'package:geolocator/geolocator.dart';
import 'package:osm_nominatim/osm_nominatim.dart';
import '../models/location.dart';
import '../utils/helper.dart';

class LocationSelector extends StatefulWidget {
  final Function(MyLocation) onLocationChanged; // Callback function

  const LocationSelector({super.key, required this.onLocationChanged});

  @override
  LocationSelectorState createState() => LocationSelectorState();
}

class LocationSelectorState extends State<LocationSelector> {
  final TextEditingController _locationController = TextEditingController();
  String _street = '';
  String _country = '';
  String? _administrativeArea; // DE: Bundesland
  String _city = '';
  String? _subLocality; // DE: Stadtteil
  String? _postalCode;
  double? _latitude;
  double? _longitude;
  String? errorText;

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          ElevatedButton.icon(
            icon: const Icon(Icons.my_location),
            onPressed: _getCurrentLocation,
            label: const Text('Current Position'),
          ),
          const SizedBox(height: 12),
          TextField(
            controller: _locationController,
            decoration: InputDecoration(
              labelText: 'Search location',
              suffixIcon: IconButton(
                icon: const Icon(Icons.search),
                onPressed: _searchLocation,
              ),
            ),
          ),
          const SizedBox(height: 6),
          Text(
            errorText != null ? '$errorText' : '',
            style: const TextStyle(color: Colors.red),
          ),
          const SizedBox(height: 20),
          Text('Country: $_country'),
          Text('City: $_city'),
          Text('Postal Code: ${_postalCode ?? ''}'),
          Text('Street: $_street'),
          Text('State/Area: ${_administrativeArea ?? ''}'),
          Text('Latitude: ${_latitude ?? '--'}'),
          Text('Longitude: ${_longitude ?? '--'}'),
        ],
      ),
    );
  }

  void _searchLocation() async {
    String locationQuery = _locationController.text.trim();

    if (locationQuery.isEmpty) {
      _resetLocationData('Specify an address for the search');
      return;
    }

    try {
      if (isMobile) {
        List<Location> locations = await locationFromAddress(locationQuery);
        if (locations.isNotEmpty) {
          // Take first match
          Location firstLocation = locations.first;

          // Extract country and city information
          List<Placemark> placeMarks = await placemarkFromCoordinates(
              firstLocation.latitude, firstLocation.longitude);
          if (placeMarks.isNotEmpty) {
            Placemark placeMark = placeMarks.first;
            setState(() {
              _latitude = firstLocation.latitude;
              _longitude = firstLocation.longitude;
              _street = placeMark.street ?? '';
              _country = placeMark.country ?? '';
              _city = placeMark.locality ?? '';
              _subLocality = placeMark.subLocality;
              _postalCode = placeMark.postalCode;
              _administrativeArea = placeMark.administrativeArea;
              errorText = null;
            });
            // location is found, trigger callback
            triggerCallback();
          } else {
            setState(() {
              // should placeMarks be empty return latitude and longitude anyway
              _latitude = firstLocation.latitude;
              _longitude = firstLocation.longitude;
              errorText = null;
            });
          }
        } else {
          _resetLocationData('Location $locationQuery not found');
        }
      } else {
        // other platforms than Android or iOS

        try {
          List<Place> searchResult = await Nominatim.searchByName(
            query: locationQuery,
            limit: 1,
            addressDetails: true,
            nameDetails: true,
          );

          Map<String, dynamic>? addressData = searchResult.single.address;
          if (addressData != null) {
            String street = _getStreetInfo(addressData);
            String city = _getCityInfo(addressData);

            setState(() {
              _latitude = searchResult.single.lat;
              _longitude = searchResult.single.lon;
              _street = street;
              _country = addressData.containsKey('country')
                  ? addressData['country']
                  : '';
              _administrativeArea = addressData.containsKey('state')
                  ? addressData['state']
                  : null;
              _city = city;
              _subLocality = addressData.containsKey('suburb')
                  ? addressData['suburb']
                  : null;
              _postalCode = addressData.containsKey('postcode')
                  ? addressData['postcode']
                  : null;
              errorText = null;
            });
            triggerCallback();
          }
        } catch (e) {
          _resetLocationData('Error looking up location $locationQuery: $e');
        }
      }
    } catch (e) {
      _resetLocationData('Error searching location $locationQuery: $e');
    }
  }

  void triggerCallback() {
    widget.onLocationChanged(MyLocation(
      street: _street,
      country: _country,
      administrativeArea: _administrativeArea,
      locality: _city,
      subLocality: _subLocality,
      postalCode: _postalCode,
      latitude: _latitude,
      longitude: _longitude,
    ));
  }

  /// Resets the location data and calls setState()
  void _resetLocationData(String errorMessage) {
    setState(() {
      errorText = errorMessage;
      _street = '';
      _country = '';
      _city = '';
      _subLocality = null;
      _postalCode = null;
      _administrativeArea = null;
      _latitude = null;
      _longitude = null;
    });
  }

  /// Determine users current position
  void _getCurrentLocation() async {
    bool serviceEnabled;
    LocationPermission permission;

    try {
      // Test if location services are enabled.
      serviceEnabled = await Geolocator.isLocationServiceEnabled();
      if (!serviceEnabled) {
        // Location services are not enabled, don't continue
        // accessing the position and request users of the
        // App to enable the location services.
        setState(() {
          errorText = 'Location services are disabled. '
              'Enable location services and try again.';
        });

        return;
      }

      permission = await Geolocator.checkPermission();
      if (permission == LocationPermission.denied) {
        permission = await Geolocator.requestPermission();
        if (permission == LocationPermission.denied) {
          // Permissions are denied, next time you could try
          // requesting permissions again (this is also where
          // Android's shouldShowRequestPermissionRationale
          // returned true. According to Android guidelines
          // your App should show an explanatory UI now.
          setState(() {
            errorText = 'Location permissions are denied';
          });
          return;
        }
      }

      if (permission == LocationPermission.deniedForever) {
        // Permissions are denied forever, handle appropriately.
        setState(() {
          errorText =
              'Location permissions are permanently denied, cannot request permissions.';
        });
        return;
      }
    } catch (e) {
      errorText = 'Error getting location permission: $e';
    }

    try {
      // When we reach here, permissions are granted and we can
      // continue accessing the position of the device.
      Position position = await Geolocator.getCurrentPosition(
          desiredAccuracy: LocationAccuracy.high);

      if (isMobile) {
        // using package geocoding which works for Android and iOS only
        List<Placemark> placeMarks = await placemarkFromCoordinates(
            position.latitude, position.longitude);

        if (placeMarks.isNotEmpty) {
          Placemark placeMark = placeMarks.first;
          setState(() {
            _street = placeMark.street ?? '';
            _country = placeMark.country ?? '';
            _city = placeMark.locality ?? '';
            _administrativeArea = placeMark.administrativeArea;
            _latitude = position.latitude;
            _longitude = position.longitude;
            errorText = null;
          });
          triggerCallback();
        }
      } else {
        // using osm_nominatim for other platforms than Android and iOS
        try {
          Place reverseSearchResult = await Nominatim.reverseSearch(
            lat: position.latitude,
            lon: position.longitude,
            addressDetails: true,
            nameDetails: true,
          );

          Map<String, dynamic>? addressData = reverseSearchResult.address;

          if (addressData != null) {
            String street = _getStreetInfo(addressData);
            String city = _getCityInfo(addressData);

            setState(() {
              _latitude = position.latitude;
              _longitude = position.longitude;
              _street = street;
              _country = addressData.containsKey('country')
                  ? addressData['country']
                  : '';
              _administrativeArea = addressData.containsKey('state')
                  ? addressData['state']
                  : null;
              _city = city;
              _subLocality = addressData.containsKey('suburb')
                  ? addressData['suburb']
                  : null;
              _postalCode = addressData.containsKey('postcode')
                  ? addressData['postcode']
                  : null;
              errorText = null;
            });
            triggerCallback();
          }
        } catch (e) {
          errorText = 'Error looking up current location: $e';
        }
      }
    } catch (e) {
      errorText = 'Error getting current location: $e';
    }
  }

  // Categories according to OSM tagging are not always consistent.
  // https://nominatim.org/release-docs/latest/api/Output/#addressdetails

  /// Try to get nominatim street information.
  String _getStreetInfo(Map<String, dynamic> addressData) {
    String street = '';
    if (addressData.containsKey('road')) {
      street = addressData['road'];
    } else if (addressData.containsKey('locality')) {
      street = addressData['locality'];
    } else if (addressData.containsKey('city_block')) {
      street = addressData['city_block'];
    }
    return street;
  }

  /// Try to get nominatim city information.
  String _getCityInfo(Map<String, dynamic> addressData) {
    String city = '';
    if (addressData.containsKey('city')) {
      city = addressData['city'];
    } else if (addressData.containsKey('village')) {
      city = addressData['village'];
    } else if (addressData.containsKey('town')) {
      city = addressData['town'];
    }
    return city;
  }
}