public static PaymentPlanOutputEntry ApplyMonthlyPayment(DateTime currentDate, DebtEntry debtEntry,
PaymentManager paymentManager, double additionalPrinciple = 0)
{
double startingBalance = debtEntry.CurrentBalance;
double interestPortion = debtEntry.MonthlyInterest * debtEntry.CurrentBalance;
double minimumPrinciple = debtEntry.MinimumMonthlyPayment - interestPortion;
double principalPortion = minimumPrinciple + additionalPrinciple;
double possibleBalance = debtEntry.CurrentBalance -= principalPortion;
if (possibleBalance < 0)
{
debtEntry.CurrentBalance = 0;
paymentManager.AddWindfallEntry(Math.Abs(possibleBalance), currentDate.AddMonths(1));
}
else
{
debtEntry.CurrentBalance = possibleBalance;
}
PaymentPlanOutputEntry output = PaymentPlanOutputEntry.Create(
debtEntry.Name, currentDate, startingBalance, interestPortion,
minimumPrinciple, additionalPrinciple, debtEntry.CurrentBalance);
//PaymentPlanOutputEntry.WriteToConsole(output);
return output;
}
public static DebtEntry CreateDebtEntry(string name, double startBalance, double currentBalance, double yearlyInterest, int loanTerm)
{
DebtEntry debtEntry = new DebtEntry()
{
Name = name,
StartingBalance = startBalance,
CurrentBalance = currentBalance,
YearlyInterestRate = yearlyInterest,
LoanTerm = loanTerm
};
InitializeMonthlyPayment(debtEntry);
return debtEntry;
}
public bool AddDebtEntry(DebtEntry debtEntry)
{
_debtEntries.Add(debtEntry);
return true;
}
protected static void InitializeMonthlyPayment(DebtEntry debtEntry)
{
debtEntry.MonthlyInterest = debtEntry.YearlyInterestRate * _yearly_to_monthly_interest_term_inverse;
double monthlyInterest_Loan_Term = Math.Pow ((1 + debtEntry.MonthlyInterest), debtEntry.LoanTerm);
debtEntry.MinimumMonthlyPayment = debtEntry.MonthlyInterest * debtEntry.StartingBalance * monthlyInterest_Loan_Term / (monthlyInterest_Loan_Term - 1);
}