using System;

​

public class Program

{

    public static void Main()

    {

        // This is exactly why you write unit tests. This is almost a unit test for the function private static DateTimeOffset ComputeInfoIntoUtcTime(DateTime initialTime, string timeZoneName)

        string clientLocalTimeZone = "Eastern Standard Time"; // -5 < 3/11/18 2:00 AM -4 >= 3/11/18 2:00 AM Step 3 should include doing the query to retrieve this from the Client setup information

        TimeSpan offset = new TimeSpan(0, -5, 0, 0); // match local time

        TimeSpan dstOffset = new TimeSpan(0, -4, 0, 0); // match local time

        DateTime startTime = new DateTime(2018, 3, 10); // 3/10/2018 (from UI) Step 3 should include creating this as a DateTime

        TimeSpan currentTime = new TimeSpan(0, 7, 0, 0); // 7 AM (from UI) Step 3 should include creating this as a TimeSpan (based on yesterday's work)

        startTime = startTime.Add(currentTime); // Combine both

        DateTimeOffset startTimeWithTimeZone = CombineInitialTimeAndTimeZone(startTime, clientLocalTimeZone);

        Console.WriteLine("Converted to {0}: {1}", clientLocalTimeZone, startTimeWithTimeZone);

        Console.WriteLine("Converted to UTC: {0}", startTimeWithTimeZone.ToUniversalTime()); // +5 hours

        if (startTimeWithTimeZone.Offset == offset) // if this was a unit test, this would be an assert.

        {

            Console.WriteLine("Unit test correctly accounted for " + clientLocalTimeZone + " DST conditions");

        }

        else

        {

            throw new Exception("Unit test for " + clientLocalTimeZone + " DST conditions failed.");

        }

​

        startTime = new DateTime(2018, 3, 12); // 3/12/2018 (from UI) Step 3 should include creating this as a DateTime

        currentTime = new TimeSpan(0, 7, 0, 0); // 7 AM (from UI) Step 3 should include creating this as a TimeSpan (based on yesterday's work)

        startTime = startTime.Add(currentTime); // Combine both

        startTimeWithTimeZone = CombineInitialTimeAndTimeZone(startTime, clientLocalTimeZone);

        Console.WriteLine("Converted to {0}: {1}", clientLocalTimeZone, startTimeWithTimeZone);

        Console.WriteLine("Converted to UTC: {0}", startTimeWithTimeZone.ToUniversalTime()); // +4 hours

        if (startTimeWithTimeZone.Offset == dstOffset) // if this was a unit test, this would be an assert.

        {

            Console.WriteLine("Unit test correctly accounted for " + clientLocalTimeZone + " DST conditions");

        }

        else

        {

            throw new Exception("Unit test for " + clientLocalTimeZone + " DST conditions failed.");

        }

    }

​

    private static DateTimeOffset CombineInitialTimeAndTimeZone(DateTime initialTime, string timeZoneName)

    {

        DateTimeOffset result;

        TimeZoneInfo info = TimeZoneInfo.FindSystemTimeZoneById(timeZoneName); // get the local time zone (step 4)

        TimeSpan offset = info.GetUtcOffset(initialTime); // based on the start time, compute the offset (step 5a)

        result = new DateTimeOffset(initialTime, offset); // create a date time offset based off of the initial time in the correct time zone based on the starting time (step 5b)

        return result;

    }

}