/// <summary>
/// The number of periods per year for a given UnitPeriod
/// </summary>
internal static double PeriodsPerYear(UnitPeriod period)
{
return(period.periodType switch
{
UnitPeriodType.Monthly => Convert.ToDouble(12d / period.numPeriods),
UnitPeriodType.Weekly => Convert.ToDouble(52d / period.numPeriods),
UnitPeriodType.Yearly => 1d,//The maximum UnitPeriod is 1 year, so this is always 1 (as opposed to say .5 for a 2 year common period)
UnitPeriodType.Daily => Convert.ToDouble(365d / period.numPeriods),
_ => throw new ApplicationException("Invalid Unit Period Type passed into DaysPerPeriod"),
});
/// <summary>
/// Finished Adding Line Items, must be used prior to adding to APR
/// </summary>
public void MarkComplete()
{
this.Sort();
//And now we calculate the Unit Period
this.m_CommonPeriod = DateTimeCalculations.CalculateCommonPeriod(this);
this.m_DaysPerPeriod = DateTimeCalculations.DaysPerPeriod(this.m_CommonPeriod);
this.m_PeriodsPerYear = DateTimeCalculations.PeriodsPerYear(this.m_CommonPeriod);
//Mark all line items as complete
for (int i = 0; i < this.m_Items.Count; i++)
{
LineItem li = (LineItem)this.m_Items[i];
li.Complete();
}
m_Completed = true;
}
internal static double GetPVIFA(DateTime StartDate, DateTime CurrLIDate, UnitPeriod frequency, double APR, double PeriodsPerYear, double DaysPerPeriod, int NumberOccurrences, UnitPeriod CommonPeriod)
{
StringBuilder sb = new StringBuilder();
int ic = 1;
double pvifa = 0.0d; //return value, running tally of PVIF
PeriodSpan lastSpan;
PeriodSpan currSpan = DateTimeCalculations.GetNumberPeriods(StartDate, CurrLIDate, CommonPeriod);
lastSpan.OddDays = 0;
lastSpan.Periods = 0;
for (int i = 0; i < NumberOccurrences; i++)
{
//get the PVIF for this current item and add to the pvifa
pvifa += GetPVIF(currSpan, APR, PeriodsPerYear, DaysPerPeriod);
sb.AppendLine(ic.ToString() + " " + CurrLIDate.ToString() + " " + currSpan.Periods.ToString() + currSpan.OddDays.ToString() + " " + pvifa.ToString());
//TODO... figure out how to determine the recurrence in periods if
//periods other than a monthly type or annual are passed in.
//Perhaps we should restrict to only dates instead?
lastSpan = currSpan;
CurrLIDate = DateTimeCalculations.AddPeriodToDate(CurrLIDate, frequency);
currSpan = DateTimeCalculations.GetNumberPeriods(StartDate, CurrLIDate, CommonPeriod);
}
return(pvifa);
}
/// <summary>
/// Gets a Date based on a given period in the Loan Lifecycle.
/// </summary>
internal static DateTime GetDateFromPeriod(PeriodSpan Span, DateTime StartDate, UnitPeriod CommonPeriod)
{
DateTime dtReturn;
try
{
if (CommonPeriod.periodType == UnitPeriodType.Monthly)
{
dtReturn = StartDate.AddMonths(CommonPeriod.numPeriods * Span.Periods).AddDays(Span.OddDays);
}
else if (CommonPeriod.periodType == UnitPeriodType.Yearly)
{
dtReturn = StartDate.AddYears(CommonPeriod.numPeriods * Span.Periods).AddDays(Span.OddDays);
}
else if (CommonPeriod.periodType == UnitPeriodType.Weekly)
{
dtReturn = StartDate.AddDays(CommonPeriod.numPeriods * Span.Periods * 7).AddDays(Span.OddDays);
}
else
{
dtReturn = StartDate.AddDays(CommonPeriod.numPeriods * Span.Periods);
}
return(dtReturn);
}
catch (Exception ex)
{
ApplicationException newex = new ApplicationException("Exception in DateTimeCalculations.GetDateFromPeriod", ex);
throw(newex);
}
}