public static IEnumerable <InstallmentForRepaymentPlanModel> GetDecreasingPlan(NewLoanRequestModel requestModel)
{
var actualPeriod = requestModel.Period - requestModel.GracePeriod;
var principalInstallment = Math.Round(requestModel.LoanAmount / actualPeriod, 2);
var lastPrincipalInstallment = requestModel.LoanAmount - (actualPeriod - 1) * principalInstallment;
var installments = new Dictionary <int, InstallmentForRepaymentPlanModel>();
var startingFees = CalcHelpers.CalculateStartingFeesCost(requestModel.LoanAmount, requestModel.Fees);
var zero = new InstallmentForRepaymentPlanModel
{
Id = 0,
Date = DateTime.UtcNow.Date,
MonthlyInstallment = 0,
PrincipalInstallment = 0,
InterestInstallment = 0,
PrincipalBalance = requestModel.LoanAmount,
Fees = startingFees,
CashFlow = requestModel.LoanAmount - startingFees
};
installments.Add(0, zero);
for (var i = 1; i <= requestModel.Period; i++)
{
var interest = i <= requestModel.PromoPeriod ? requestModel.PromoInterest : requestModel.Interest;
decimal currentPrincipalBalance;
decimal interestInstallment;
decimal currentPrincipalInstallment;
if (i <= requestModel.GracePeriod)
{
currentPrincipalBalance = requestModel.LoanAmount;
interestInstallment = CalcHelpers.CalculateInterestInstallment(interest, currentPrincipalBalance);
currentPrincipalInstallment = 0;
}
else
{
currentPrincipalBalance = CalcHelpers.CalculatePrincipalBalance(installments[i - 1]);
interestInstallment = CalcHelpers.CalculateInterestInstallment(interest, currentPrincipalBalance);
currentPrincipalInstallment = i == requestModel.Period ? lastPrincipalInstallment : principalInstallment;
}
var monthlyInstallment = interestInstallment + currentPrincipalInstallment;
var fees = CalcHelpers.CalculateFeesCost(i, currentPrincipalBalance, requestModel.Fees);
installments.Add(i, new InstallmentForRepaymentPlanModel
{
Id = i,
Date = DateTime.UtcNow.Date.AddDays(i),
MonthlyInstallment = monthlyInstallment,
PrincipalInstallment = currentPrincipalInstallment,
InterestInstallment = interestInstallment,
PrincipalBalance = currentPrincipalBalance,
Fees = fees,
CashFlow = -monthlyInstallment - fees
});
}
return(installments.Select(x => x.Value));
}
public static decimal CalculatePrincipalBalance(InstallmentForRepaymentPlanModel previousInstallment)
{
return(previousInstallment.PrincipalBalance - previousInstallment.PrincipalInstallment);
}
