protected override IResult <Response> HandleSync(Request request)
{
try
{
var totalPrincipal = request.AssetCost - request.DownPayment;
var numberOfPeriods = request.NumberOfYears * request.PeriodsPerYear;
var ratePerPeriod = request.AnnualInterestRate == 0 ? 0 : request.AnnualInterestRate / request.PeriodsPerYear;
var amortizationRequest = new AmortizationRequest(totalPrincipal, numberOfPeriods, ratePerPeriod);
var amortizationResponse = _amortizationCalculator.Calculate(amortizationRequest);
var response = new Response(
totalPrincipal: totalPrincipal,
paymentPerPeriod: amortizationResponse.PaymentPerPeriod + request.EscrowPerPeriod,
totalInterestPaid: amortizationResponse.TotalInterestPaid,
totalEscrowPaid: request.EscrowPerPeriod * numberOfPeriods,
totalPaid: request.AssetCost + amortizationResponse.TotalInterestPaid + request.EscrowPerPeriod * numberOfPeriods,
schedule: amortizationResponse.Schedule);
return(Ok(response));
}
catch (System.AggregateException ex)
{
if (ex.InnerExceptions.All(e => e.GetType() == typeof(System.OverflowException)))
{
return(Fail(new LoanOverflowFailure()));
}
else
{
throw;
}
}
}
/// <summary>
/// Calculate the loan request.
/// </summary>
/// <param name="request">The request to calculate</param>
/// <returns>A completed AmortizationResponse</returns>
/// <exception cref="ArgumentNullException">Throws when request is null.</exception>
public AmortizationResponse Calculate(AmortizationRequest request)
{
if (request is null)
{
throw new ArgumentNullException(nameof(request), "Calculator request cannot be null.");
}
var ratePerPeriod = request.RatePerPeriod;
var numberOfPeriods = request.NumberOfPeriods;
var totalPrincipal = request.TotalPrincipal;
var schedule = new AmortizationPeriod[numberOfPeriods];
Parallel.For(1, numberOfPeriods + 1, periodNumber =>
{
var principalPayment = _financial.PrincipalPayment(ratePerPeriod, periodNumber, numberOfPeriods, -totalPrincipal);
var interestPayment = _financial.InterestPayment(ratePerPeriod, periodNumber, numberOfPeriods, -totalPrincipal);
var balanceLeft = ratePerPeriod == 0 ?
totalPrincipal - (principalPayment * periodNumber) :
_financial.InterestPayment(ratePerPeriod, periodNumber + 1, numberOfPeriods, -totalPrincipal) / ratePerPeriod;
schedule[periodNumber - 1] = new AmortizationPeriod(periodNumber, interestPayment, principalPayment, balanceLeft);
});
var paymentPerPeriod = _financial.Payment(ratePerPeriod, numberOfPeriods, -totalPrincipal);
var totalInterestPaid = schedule.Sum(p => p.InterestPayment);
var totalPaid = totalPrincipal + totalInterestPaid;
return(new AmortizationResponse(paymentPerPeriod, totalInterestPaid, totalPaid, schedule, request));
}
internal AmortizationResponse(decimal paymentPerPeriod, decimal totalInterestPaid, decimal totalPaid, IReadOnlyList <AmortizationPeriod> schedule, AmortizationRequest request)
{
PaymentPerPeriod = paymentPerPeriod;
TotalInterestPaid = totalInterestPaid;
TotalPaid = totalPaid;
Schedule = schedule;
Request = request;
}
