System.DateTimeExtensions.ForecastEndDate C# (CSharp) Метод

		public static DateTime? ForecastEndDate(this DateTime? startDate, DateTime now, decimal? progress)
		{
			if (progress == null || progress.Value <= 0.01m || progress.Value >= 1m || startDate == null || startDate > now)
			{
				return null;
			}
			if (progress <= 0.1m)
			{
				return null;
			}
			TimeSpan passedDuration = now - startDate.Value;
			if (passedDuration.TotalDays <= 7)
			{
				return null;
			}
			decimal stepInMs = (decimal) (passedDuration.TotalMilliseconds * 0.01) / progress.Value;
			decimal forecastDurationInMs = stepInMs * (1 - progress.Value) * 100;
			TimeSpan forecastDuration = TimeSpan.FromMilliseconds((long) Math.Ceiling(forecastDurationInMs));
			DateTime predictedEndDate = now + forecastDuration;
			return predictedEndDate;
		}