using System;

​

public class Program

{

    public static void Main()

    {

        DateTime endDate;

        var dto = new TimeCardImportStandardDto()

        {Hours = "7.33"};

        //act

        DateTime startTime = DateTime.SpecifyKind(new DateTime(2022, 3, 12, 18, 55, 00), DateTimeKind.Unspecified);

        var expectedEndDate = TimeZoneInfo.Local.DisplayName != TimeZoneInfo.Utc.DisplayName && startTime.Kind == DateTimeKind.Utc ? new DateTime(2022, 3, 13, 2, 14, 48) : new DateTime(2022, 3, 13, 3, 14, 48);

        Console.WriteLine($"expectedEndDate: {expectedEndDate}");

        dto.TryParseEndDate(startTime, out endDate);

        Console.WriteLine($"test: {endDate == expectedEndDate}");

        Console.WriteLine("----------------------------------------------------");

        startTime = DateTime.SpecifyKind(new DateTime(2022, 3, 12, 18, 55, 00), DateTimeKind.Utc);

        expectedEndDate = TimeZoneInfo.Local.DisplayName != TimeZoneInfo.Utc.DisplayName && startTime.Kind == DateTimeKind.Utc ? new DateTime(2022, 3, 13, 2, 14, 48) : new DateTime(2022, 3, 13, 3, 14, 48);

        Console.WriteLine($"expectedEndDate: {expectedEndDate}");

        dto.TryParseEndDate(startTime, out endDate);

        Console.WriteLine($"test: {endDate == expectedEndDate}");

        Console.WriteLine("----------------------------------------------------");

        startTime = DateTime.SpecifyKind(new DateTime(2022, 3, 12, 18, 55, 00), DateTimeKind.Local);

        expectedEndDate = TimeZoneInfo.Local.DisplayName != TimeZoneInfo.Utc.DisplayName && startTime.Kind == DateTimeKind.Utc ? new DateTime(2022, 3, 13, 2, 14, 48) : new DateTime(2022, 3, 13, 3, 14, 48);

        Console.WriteLine($"expectedEndDate: {expectedEndDate}");

        dto.TryParseEndDate(startTime, out endDate);

        Console.WriteLine($"test: {endDate == expectedEndDate}");

    }

}

​

public class TimeCardImportStandardDto

{

    public string Hours { get; set; }

}

​

public static class DateTimeExtensions

{

    public static bool TryParseEndDate(this TimeCardImportStandardDto dto, DateTime startDate, out DateTime endDate)

    {

        var hoursParsed = float.TryParse(dto.Hours?.Trim(), out float hours);

        endDate = default;

        if (!hoursParsed)

        {

            return false;

        }

​

        var minutesToAdd = Math.Round(hours * 60.00, 5);

        endDate = startDate.ToUniversalTime().AddMinutes(minutesToAdd);

        endDate = DateTime.SpecifyKind(startDate.Kind == DateTimeKind.Utc ? endDate : endDate.ToLocalTime(), startDate.Kind);

        Console.WriteLine($"endDate {endDate}");

        return true;

    }

}