/// <summary>
/// Calculates subsequent end times based on the surrounding duration values
/// </summary>
/// <param name="currentEndTime">The current end time.</param>
/// <param name="adjustedDuration">Duration of the adjusted.</param>
/// <param name="nextDuration">Duration of the next.</param>
/// <returns></returns>
private DateTime CalculateEndTime(DateTime currentEndTime, TimeSpan adjustedDuration, TimeSpan nextDuration)
{
TraceFactory.Logger.Debug("ET: {0}, AD: {1}, ND: {2}"
.FormatWith(currentEndTime, adjustedDuration, nextDuration));
// Pick a simple way to "randomly" decide if the variance will be positive or negative.
bool isPositive = currentEndTime.Ticks % 2 == 0;
// Calculate the variance for the current duration, which has been adjusted to account for the end time
// of the last segment. This asjusted duration may be larger or smaller than its default value.
var variance = Variance(adjustedDuration);
TraceFactory.Logger.Debug("Variance {0}".FormatWith(variance));
// This variance can't extend beyond 1/2 of the next duration, if it is positive.
if (isPositive)
{
TimeSpan halfNextDuration = TimeSpanUtil.Divide(nextDuration, 2);
if (variance > halfNextDuration)
{
// Keep the variance to some value less than 1/2 of this shorter duration
variance = TimeSpanUtil.GetRandom(halfNextDuration);
TraceFactory.Logger.Debug("Variance reduced {0}".FormatWith(variance));
}
}
// Return the new end time based on the current end time, plus the current duration,
// then +/- the variance.
var newDuration = currentEndTime.Add(adjustedDuration);
return(isPositive ? newDuration.Add(variance) : newDuration.Subtract(variance));
}
private TimeSpan Variance(TimeSpan duration)
{
// Determine a variance maximum value by taking 12.5% of the duration's current size. The 12.5% value is
// one half of an overall 25% value (12.5% on each side of the transition boundary). Then use that
// maximum value to calculate a new random value between zero and the maximum value.
TimeSpan varianceMax = TimeSpanUtil.Divide(duration, 8);
return(TimeSpanUtil.GetRandom(varianceMax));
}