using System;

using RestSharp;

/* ------------------------------------

Copied from: http://jasonwatmore.com/post/2013/07/31/C-Get-time-zone-and-UTC-offset-from-latitude-and-longitude-%28GPS-coordinates%29.aspx

------------------------------------ */

​

public class Program

{

    public static void Main()

    {

        //LA

        //var myDateTime = GetLocalDateTime(33.8323, -117.8803, DateTime.UtcNow);

        //Melb

        var myDateTime = GetLocalDateTime(-37.9716929,144.7729587, DateTime.UtcNow);

​

        //Toronto

        //var myDateTime = GetLocalDateTime(43.949164,-78.293462, DateTime.UtcNow);

        ShowTimeZone(myDateTime.TimeZone);

        Console.WriteLine("Current Local time: {0:ddd d-MMM-yyyy h:mm:ss tt} (UTC {1})", myDateTime.LocalTime, myDateTime.Offset.AsHours());

    }

    public static TimeZoneWithDateTime GetLocalDateTime(double latitude, double longitude, DateTime utcDate)

    {

        var client = new RestClient("https://maps.googleapis.com");

        var request = new RestRequest("maps/api/timezone/json", Method.GET);

        request.AddParameter("location", latitude + "," + longitude);

        request.AddParameter("timestamp", utcDate.ToTimestamp());

        //request.AddParameter("sensor", "false");

        ShowFullUrl(client, request);

        var response = client.Execute<GoogleTimeZone>(request);

        return new TimeZoneWithDateTime(response.Data, utcDate);

    }

    public static void ShowFullUrl(RestClient client, RestRequest request)

    {

        var fullUrl = client.BuildUri(request);

        Console.WriteLine("URL: {0}", fullUrl);

        Console.WriteLine();

    }

    public static void ShowTimeZone(GoogleTimeZone data)

    {

        var offset = TimeSpan.FromSeconds(data.rawOffset + data.dstOffset);

        Console.WriteLine("TimeZone: {0}, {1}, {2}", data.timeZoneId, data.timeZoneName, offset.AsHours());

    }

}

​

public class TimeZoneWithDateTime

{

    public TimeZoneWithDateTime( GoogleTimeZone timeZone, DateTime utcTime)

    {

        TimeZone =timeZone;

        UtcTime = utcTime;

    }

​

    public readonly GoogleTimeZone TimeZone;

    public readonly DateTime UtcTime;

    public TimeSpan Offset

    {

        get 

        {

            return TimeSpan.FromSeconds(TimeZone.rawOffset + TimeZone.dstOffset);

        }

    }

    public DateTimeOffset LocalTime

    { 

        get 

        {

            var localDateTime = DateTime.SpecifyKind(UtcTime.AddSeconds(Offset.TotalSeconds), DateTimeKind.Unspecified);

            //return a DateTimeOffset using the Ticsk property (which strips out the DateTIme offset), and the required offset

            return new DateTimeOffset(localDateTime.Ticks, Offset);

        }

    }

}

​

public class GoogleTimeZone 

{

    public double dstOffset { get; set; }

    public double rawOffset { get; set; }

    public string status { get; set; }

    public string timeZoneId { get; set; }

    public string timeZoneName { get; set; }

}

​

public static class ExtensionMethods 

{

    public static double ToTimestamp(this DateTime date)

    {

        DateTime origin = new DateTime(1970, 1, 1, 0, 0, 0, 0);

        TimeSpan diff = date.ToUniversalTime() - origin;

        return Math.Floor(diff.TotalSeconds);

    }

    public static string AsHours(this TimeSpan offset)

    {

        var adj = "";

        if (offset > TimeSpan.Zero)

            adj = "+";

        adj += string.Format("{0}:{1:00} hours", offset.Hours, offset.Minutes);

        return adj;             

    }   

}