using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml;

namespace SafeMobileLib
{
    public class ReverseGeocoding
    {
        private String ReverseGeoOSM = "127.0.0.1";

        public ReverseGeocoding(String ReverseGeoOSM)
        {
            this.ReverseGeoOSM = ReverseGeoOSM;

            doc = new XmlDocument();
        }

        private volatile XmlDocument doc = null;
        private volatile XmlNode element = null;
        private volatile String addr = "";


        public enum Provider { OSM, GOOGLE, ANY }

        public string getAddressLATLNG(Double LAT, Double LNG)
        {
            return getLatLngFromProvider(LAT, LNG, Provider.ANY);
        }

        public void getCoordinates(String address, out decimal LAT, out decimal LNG)
        {
            LNG = -181; LAT = -181;
            try
            {
                doc.Load("http://maps.googleapis.com/maps/api/geocode/xml?address=" + address + "&sensor=false");
                element = doc.SelectSingleNode("//GeocodeResponse/status");
                if (element.InnerText == "OK")
                {
                    element = doc.SelectSingleNode("//GeocodeResponse/result/geometry/location/lat");
                    LAT = Convert.ToDecimal(element.InnerText);
                    element = doc.SelectSingleNode("//GeocodeResponse/result/geometry/location/lng");
                    LNG = Convert.ToDecimal(element.InnerText);

                    Utils.WriteLine($"Coordinates calc from google for address {address} are [{LAT},{LNG}]");
                }
                else
                {
                    Utils.WriteLine($"Unable to get coordinates from google [{address}]. Response is {element.InnerText}");
                }
            }
            catch (Exception ex)
            {
                Utils.WriteLine("Unable to do coordinates calc from google");
            }

        }

        public string getAddressLATLNG2(Double LAT, Double LNG)
        {
            return getLatLngFromProvider(LAT, LNG, Provider.ANY);
        }


        private string getLatLngFromProvider(double LAT, double LNG, Provider provider)
        {
            bool errorFound = false;
            string address = "";

            if (provider == Provider.OSM || provider == Provider.ANY)
            {
                Utils.WriteLine($"Doing reverse geocoding through OSM for [{LAT}:{LNG}]");
                addr = "";

                address = $"{ReverseGeoOSM}?format=xml&lat={(LAT.ToString()).Replace(',', '.')}&lon={(LNG.ToString()).Replace(',', '.')}&zoom=18&addressdetails=1";

                try
                {

                    doc.Load(address);
                    element = doc.SelectSingleNode("//reversegeocode/result");
                    addr = element?.InnerText.Replace("'", "`");
                    if (addr == null)
                    {
                        element = doc.SelectSingleNode("//reversegeocode/error");
                        addr = element?.InnerText.Replace("'", "`");
                    }
                    if (addr.Contains("Unable to geocode"))
                    {
                        addr = "N/A";
                        errorFound = true;
                    }
                    if (addr.StartsWith("Fail"))
                    {
                        addr = "N/A";
                        errorFound = true;
                    }
                }
                catch (Exception ex)
                {
                    errorFound = true;
                    Utils.WriteLine($"Unable to do Reverse Geocoding from OSM [{LAT},{LNG}] @ {address}. Response is {ex.ToString()}");
                }
            }

            if (provider == Provider.GOOGLE || (provider == Provider.ANY && errorFound))
            {
                addr = "";
                try
                {
                    doc.Load("http://maps.googleapis.com/maps/api/geocode/xml?latlng=" + (LAT.ToString()).Replace(',', '.') + "," + (LNG.ToString()).Replace(',', '.') + "&sensor=false");
                    element = doc.SelectSingleNode("//GeocodeResponse/status");
                    if (element.InnerText == "OK")
                    {
                        element = doc.SelectSingleNode("//GeocodeResponse/result/formatted_address");
                        addr = element.InnerText.Replace("'", "`");
                        Utils.WriteLine($"Reverse Geocoding [{LAT},{LNG}] is {addr}");
                    }
                    else
                    {
                        errorFound = true;
                        Utils.WriteLine($"Unable to do Reverse Geocoding from google [{LAT},{LNG}]. Response is {element.InnerText}");

                    }
                }
                catch (Exception ex)
                {
                    errorFound = true;
                    Utils.WriteLine("Unable to do Reverse Geocoding from google");
                }
            }


            return addr;
        }

    }
}