public bool CreateMortgage(MortgageDetail model, int id)
{
var entity = new Mortgage()
{
UserID = _userId,
PropertyID = id,
Interest = model.Interest,
Period = model.Period,
Payment = model.Payment,
TotalLoanAmount = model.TotalLoanAmount,
MonthlyPayment = model.MonthlyPayment,
};
using (var ctx = new ApplicationDbContext())
{
ctx.Mortgages.Add(entity);
return(ctx.SaveChanges() == 1);
}
}
public ActionResult MortgageCalculator(MortgageDetail model, int id)
{
var svc = CreateMortgageService();
//add new mortgage object to database with necessary properties provided by user
svc.CreateMortgage(model, id);
//get mortgage object that was just made
var detail = svc.GetMortgageByPropertyID(id);
//This section is where I convert the formulas for calculating a mortgage into code. While PEMDAS logic remains constant, the formula requires use of ^ which means something different in this language than in mathematics. To resolve this I created multiple variables to break up the formulas calculations into smaller portions. I've included the formulas below to make it easier to follow the logic.
/*M = monthly payment, P = principal, I = interest, N = number of payments, R = monthly interest rate
*/
//interest rate comes in at values above for apr, needs to be /12 for monthly and /100 to convert to proper format
decimal monthlyInterestRate = detail.Interest / 1200;
//convert years to months
decimal newPeriod = detail.Period * 12;
double y = (double)(1 + monthlyInterestRate);
double z = (double)newPeriod;
decimal P = detail.Price - detail.Payment;
double var2 = (double)(newPeriod * (-1));
decimal x = (decimal)Math.Pow(y, z);
decimal negx = (decimal)Math.Pow(y, var2);
// formula M = P [ I(1 + I)^N ] / [ (1 + I)^N – 1]
decimal newmonthlypayment = (P * monthlyInterestRate * x) / (x - 1);
// formula Total Amount Paid For Loan = (R*P*N) / 1-((1+R)^-N)
decimal newTotalLoan = (monthlyInterestRate * P * newPeriod) / (1 - negx);
ViewBag.ResultA = newmonthlypayment;
ViewBag.ResultB = newTotalLoan;
//delete mortgage object that was just added to database
svc.DeleteAllMortgagesGivenPropertyID(id);
return(View());
}
