/// <summary>
/// Now that we have the info for the most money that can be borrowed, update the loan object with that "max" info.
/// Then compute the payments based on the rates for various items.
/// </summary>
private static void UpdateLoanInfo(LoanProviderInfo masterLoanSpecificInfo, LoanCalculationResults theCalculationResults, decimal downPaymentPercentage)
{
masterLoanSpecificInfo.LoanAmount_Base = theCalculationResults.RecommendedLoanAmount_Base;
masterLoanSpecificInfo.PrincipleAndInterestPayment = theCalculationResults.RecommendedPayment_PrincipleAndInterest;
//if (masterLoanSpecificInfo.GetType.Equals("USDA 30-year Loan", StringComparison.OrdinalIgnoreCase) = true)
masterLoanSpecificInfo.UpfrontMortgageInsurancePayment = (decimal)((masterLoanSpecificInfo.UpfrontMortgageInsuranceRate / 100) * (double)masterLoanSpecificInfo.LoanAmount_Base);
decimal annualMortgageInsurancePayment = (decimal)((masterLoanSpecificInfo.MonthlyMortgageInsuranceRate / 100) * (double)(masterLoanSpecificInfo.LoanAmount_Base + masterLoanSpecificInfo.UpfrontMortgageInsurancePayment));
masterLoanSpecificInfo.MonthlyMortgageInsurancePayment = annualMortgageInsurancePayment / 12;
decimal annualPropertyTaxPayment = (decimal)((masterLoanSpecificInfo.MonthlyPropertyTaxRate / 100) * (double)(masterLoanSpecificInfo.LoanAmount_Base + masterLoanSpecificInfo.UpfrontMortgageInsurancePayment));
masterLoanSpecificInfo.MonthlyPropertyTaxPayment = annualPropertyTaxPayment / 12;
// Add all the new payments into the loan amount.
masterLoanSpecificInfo.LoanAmount_Actual = masterLoanSpecificInfo.LoanAmount_Base + masterLoanSpecificInfo.UpfrontMortgageInsurancePayment;
masterLoanSpecificInfo.TotalLoanPayment = masterLoanSpecificInfo.PrincipleAndInterestPayment + masterLoanSpecificInfo.MonthlyMortgageInsurancePayment + masterLoanSpecificInfo.MonthlyPropertyTaxPayment;
int salesPriceIndex = masterLoanSpecificInfo.getRowForTableLookups(downPaymentPercentage);
double downPaymentModifier = SalesPriceCalculationData.SalesPriceCalculation[salesPriceIndex];
masterLoanSpecificInfo.HouseAmount_Actual = (decimal)((double)masterLoanSpecificInfo.LoanAmount_Actual / downPaymentModifier);
}
/// <summary>
/// Find how much the user can borrow for this loan type.
/// </summary>
public static void FindBestLoanAmount(LoanProviderInfo loanProviderInfo, int maxPayment, decimal downPaymentPercentage)
{
LoanCalculationResults calculationResult = new LoanCalculationResults();
calculationResult = FindBestLoanBasedOnMonthlyPayment(maxPayment, loanProviderInfo.LoanTermMonths, loanProviderInfo.InterestRate_Annual_Total, loanProviderInfo.UpfrontMortgageInsuranceRate, loanProviderInfo.MonthlyMortgageInsuranceRate, loanProviderInfo.MonthlyPropertyTaxRate);
UpdateLoanInfo(loanProviderInfo, calculationResult, downPaymentPercentage);
}
/// <summary>
/// Based on the maximum-allowable-montly-payment, find the most that can be borrowed for this loan type.
/// Iterate through scenarios based on increasing loan amount.
/// If the scenario hasn't exceeded the max payment, remember the info from the iteration and keep going.
/// Once the max payment is exceeded, we know to stop and use the last iteration's data.
/// In other words, go until you fail, then back up to the last success.
/// </summary>
private static LoanCalculationResults FindBestLoanBasedOnMonthlyPayment(int maxPayment, double loanTerm_Months, double interestRate_Annual, double upfrontRate_MI, double monthlyRate_MI, double monthlyRate_PropTax)
{
LoanCalculationResults calculationResults = new LoanCalculationResults();
bool keepLooking = true;
int index = 0;
int loanInitialAmount = LoanStartingAmount;
int loanIncrementAmount = LoanIncrementalAmount;
int currentLoanAmount_Base = 0;
int currentLoanAmount_BasePlusMortgageInsurance = 0;
decimal pAndIPayment = 0;
decimal upfrontPayment_MI = 0;
decimal monthlyPayment_MI = 0;
decimal annualMortgageInsurancePayment = 0;
decimal monthlyPayment_PropTax = 0;
decimal annualPayment_PropTax = 0;
while (keepLooking == true)
{
currentLoanAmount_Base = (loanInitialAmount + (index * loanIncrementAmount));
upfrontPayment_MI = ((decimal)((upfrontRate_MI / 100) * (double)currentLoanAmount_Base));
annualMortgageInsurancePayment = (decimal)((monthlyRate_MI / 100) * (double)(currentLoanAmount_Base + upfrontPayment_MI));
monthlyPayment_MI = annualMortgageInsurancePayment / 12;
annualPayment_PropTax = (decimal)((monthlyRate_PropTax / 100) * (double)(currentLoanAmount_Base + upfrontPayment_MI));
monthlyPayment_PropTax = annualPayment_PropTax / 12;
currentLoanAmount_BasePlusMortgageInsurance = currentLoanAmount_Base + (int)upfrontPayment_MI;
pAndIPayment = CalculatePrincipleAndInterestPayment(currentLoanAmount_BasePlusMortgageInsurance, loanTerm_Months, interestRate_Annual);
if ((pAndIPayment + monthlyPayment_MI + monthlyPayment_PropTax) > maxPayment)
{
// We have exceeded the payment maximum, so this loan info isn't valid or desired.
// We want the info that was saved off from the previous loan calculation iteration.
keepLooking = false; // max payment exceeded - Stop iterating.
}
else
{
// We haven't exceeded the payment maximum, so remember these values. (Keep going!)
// The following lines "save the data" from this iteration in case this data is the last valid data iteration.
calculationResults.RecommendedLoanAmount_Base = currentLoanAmount_Base;
calculationResults.RecommendedPayment_PrincipleAndInterest = pAndIPayment;
index++; // Keep going.
}
}
return(calculationResults);
}
