using gehGassi.Dto.Common;
using gehGassiApp.Core.Common;
using gehGassiApp.Core.Interfaces;
using gehGassiApp.Domain.Common;

namespace gehGassiApp.Core.Services
{
    /// <summary>
    /// Hilfs-Service bei der Lokalisierung eines Benutzers
    /// </summary>
    public class LocationService : ILocationService
    {
        private readonly ICountryService _countryService;
        private readonly ISettingsService _settingsService;
        private readonly IAppReportingService _appReportingService;

        private LocationDto _cachedLocation;
        private DateTimeOffset? _lastUpdate;
        private DateTimeOffset? _lastReceivedNull;

        /// <summary>
        /// Erstellt eine Instanz
        /// </summary>
        /// <param name="countryService">Instanz eines ICountryService</param>
        /// <param name="settingsService">Instanz eines ISettingsService</param>
        /// <param name="appReportingService">Instanz eines IAppReportingService</param>
        public LocationService(ICountryService countryService, ISettingsService settingsService, IAppReportingService appReportingService)
        {
            _countryService = countryService;
            _settingsService = settingsService;
            _appReportingService = appReportingService;
            _lastUpdate = null;
            _lastReceivedNull = null;
            _cachedLocation = null;
        }

        /// <summary>
        /// Holen der Lat und Lng sowie, wenn möglich Land und Bundesland
        /// </summary>
        /// <returns>Aktuelle Position des Benutzers, oder null wenn nicht möglich</returns>
        public async Task<LocationDto> GetLocationAsync()
        {
            if (_cachedLocation != null && _lastUpdate != null && _lastUpdate > DateTimeOffset.UtcNow)
            {
                return _cachedLocation;
            }

            var location = new LocationDto();
            try
            {
                var appSettings = _settingsService.GetAppSettings();
                if (appSettings.FakeGps)
                {
                    var locationDto = new LocationDto
                    {
                        Lat = appSettings.Latitude,
                        Lng = appSettings.Longitude
                    };
                    var placemarks = await Geocoding.Default.GetPlacemarksAsync(locationDto.Lat.Value, locationDto.Lng.Value);
                    if (placemarks != null &&  placemarks.Any())
                    {
                        var placemark = placemarks.FirstOrDefault();
                        locationDto.CountryCode = placemark.CountryCode.ToUpper();
                        var state = await _countryService.GetStateByNameAsync(location.CountryCode, placemark.AdminArea);
                        if (state != null)
                            locationDto.StateCode = state.Code;
                    }

                    return locationDto;
                }

                var status = await Permissions.CheckStatusAsync<Permissions.LocationWhenInUse>();
                if (status == PermissionStatus.Granted)
                {
                    var foundLocation = await Geolocation.Default.GetLastKnownLocationAsync();
                    if (foundLocation == null && (_lastReceivedNull == null || _lastReceivedNull > DateTimeOffset.UtcNow))
                    {
                        //Wenn nichts im Cache, direkt holen. Kann länger dauern
                        using var cts = new CancellationTokenSource(Constants.GpsRealtimeTimout);
                        foundLocation = await Geolocation.Default.GetLocationAsync(new GeolocationRequest(GeolocationAccuracy.Medium, Constants.GpsRealtimeTimout), cts.Token);
                        if (foundLocation == null)
                        {
                            _lastReceivedNull = DateTimeOffset.UtcNow.Add(Constants.LocationCacheTimeout);
                        }
                    }
                    if (foundLocation != null)
                    {
                        _lastReceivedNull = null;
                        location.Lat = foundLocation.Latitude;
                        location.Lng = foundLocation.Longitude;

                        var placemarks = await Geocoding.Default.GetPlacemarksAsync(foundLocation);
                        if (placemarks != null && placemarks.Any())
                        {
                            var placemark = placemarks.FirstOrDefault();
                            location.CountryCode = placemark.CountryCode.ToUpper();
                            var state = await _countryService.GetStateByNameAsync(location.CountryCode, placemark.AdminArea);
                            if (state != null)
                                location.StateCode = state.Code;
                        }
                    }
                }
            }
            catch
            {
                location = new LocationDto();
            }

            _cachedLocation = location;
            if (_cachedLocation.Lat == null && _cachedLocation.Lng == null)
                _cachedLocation = null;
            if (_cachedLocation != null)
                _lastUpdate = DateTimeOffset.UtcNow.Add(Constants.LocationCacheTimeout);
            else
                _lastUpdate = null;

            return location;
        }

        /// <summary>
        /// Gibt Lat und Long anhand einer Adresse zurück, wenn möglich
        /// </summary>
        /// <param name="address">Adresse</param>
        /// <returns>Location mit Lat und Lng oder null wenn nicht möglich</returns>
        public async Task<Location> GetLocationByAddressAsync(Address address)
        {
            if (address != null)
            {
                var status = await Permissions.CheckStatusAsync<Permissions.LocationWhenInUse>();
                if (status == PermissionStatus.Granted)
                {
                    try
                    {
                        var locations = await Geocoding.Default.GetLocationsAsync($"{address.AddressLine1} {address.Zip} {address.City} {address.CountryCode}");
                        var location = locations?.FirstOrDefault();
                        return location;
                    }
                    catch(Exception ex)
                    {
                        await _appReportingService.TrackErrorAsync(ex);
                    }
                }
            }

            return null;
        }

        /// <summary>
        /// Gibt, wenn möglich, die aktuelle Adresse zu einer Position zurück
        /// </summary>
        /// <returns>Adresse oder null, wenn keine gefunden</returns>
        public async Task<Address> GetAddressByCurrentLocationAsync()
        {
            var location = new LocationDto();
            try
            {
                var appSettings = _settingsService.GetAppSettings();
                if (appSettings.FakeGps)
                {
                    var locationDto = new LocationDto
                    {
                        Lat = appSettings.Latitude,
                        Lng = appSettings.Longitude
                    };
                    var placemarks = await Geocoding.Default.GetPlacemarksAsync(locationDto.Lat.Value, locationDto.Lng.Value);
                    if (placemarks != null && placemarks.Any())
                    {
                        var placemark = placemarks.FirstOrDefault();

                        var countryCode = placemark.CountryCode.ToUpper();
                        var stateCode = string.Empty;
                        var state = await _countryService.GetStateByNameAsync(location.CountryCode, placemark.AdminArea);
                        if (state != null)
                            stateCode = state.Code;

                        var address = new Address
                        {
                            AddressLine1 = placemark.Thoroughfare,
                            AddressLine2 = string.Empty,
                            Zip = placemark.PostalCode,
                            City = placemark.Locality,
                            State = stateCode,
                            CountryCode = countryCode
                        };
                        if (!string.IsNullOrWhiteSpace(placemark.SubThoroughfare))
                            address.AddressLine1 += $" {placemark.SubThoroughfare}";

                        if (!string.IsNullOrWhiteSpace(address.AddressLine1) && !string.IsNullOrWhiteSpace(address.Zip) && !string.IsNullOrWhiteSpace(address.City) && !string.IsNullOrWhiteSpace(address.State) && !string.IsNullOrWhiteSpace(address.CountryCode))
                            return address;
                        else
                            return null;
                    }

                    return null;
                }

                var status = await Permissions.CheckStatusAsync<Permissions.LocationWhenInUse>();
                if (status == PermissionStatus.Granted)
                {
                    var foundLocation = await Geolocation.Default.GetLastKnownLocationAsync();
                    if (foundLocation == null)
                    {
                        //Wenn nichts im Cache, direkt holen. Kann länger dauern
                        using var cts = new CancellationTokenSource(Constants.GpsRealtimeTimout);
                        foundLocation = await Geolocation.Default.GetLocationAsync(new GeolocationRequest(GeolocationAccuracy.Medium, Constants.GpsRealtimeTimout), cts.Token);
                    }

                    if (foundLocation != null)
                    {
                        location.Lat = foundLocation.Latitude;
                        location.Lng = foundLocation.Longitude;

                        var placemarks = await Geocoding.Default.GetPlacemarksAsync(foundLocation);
                        if (placemarks != null && placemarks.Any())
                        {
                            var placemark = placemarks.FirstOrDefault();

                            var countryCode = placemark.CountryCode.ToUpper();
                            var stateCode = string.Empty;
                            var state = await _countryService.GetStateByNameAsync(countryCode, placemark.AdminArea);
                            if (state != null)
                                stateCode = state.Code;

                            var address = new Address
                            {
                                AddressLine1 = placemark.Thoroughfare,
                                AddressLine2 = string.Empty,
                                Zip = placemark.PostalCode,
                                City = placemark.Locality,
                                State = stateCode,
                                CountryCode = countryCode
                            };
                            if (!string.IsNullOrWhiteSpace(placemark.SubThoroughfare))
                                address.AddressLine1 += $" {placemark.SubThoroughfare}";

                            //return address;

                            if (!string.IsNullOrWhiteSpace(address.AddressLine1) && !string.IsNullOrWhiteSpace(address.Zip) && !string.IsNullOrWhiteSpace(address.City) && !string.IsNullOrWhiteSpace(address.State) && !string.IsNullOrWhiteSpace(address.CountryCode))
                                return address;
                            else
                                return null;
                        }
                    }
                }
            }
            catch(Exception ex)
            {
                await _appReportingService.TrackErrorAsync(ex);
            }

            return null;
        }
    }
}