public static PaymentResult CalculateBalanceWithPayment(double interestRate, double payment, double balance, int year, int month)
{
PaymentResult ret = new PaymentResult();
double newrate = interestRate * 0.01;
double periodicrate = (newrate / 365);
double interest = balance * periodicrate * DateTime.DaysInMonth(year, month);
ret.Interest = interest;
if (interest > payment)
{
throw new Exception("Debit of $" + balance.ToString() + " with a rate of " + interestRate.ToString() + "% has a payment that is too low to cover interest!");
}
double red = (payment - interest);
if (red < balance)
{
ret.NewBalance = balance - red;
ret.Principal = red;
}
else
{
ret.NewBalance = balance - interest;
ret.Principal = red;
ret.NewBalance = 0;
}
return(ret);
}
public List <DebtPayment> ProcessPlan(bool Snowball, SnowballApproaches approach, double initialSnowballPayment, DateTime?initialSnowballStart = null)
{
DateTime startProcess = DateTime.Now;
DateTime cur = DateTime.Now;
List <DebtPayment> DebtPayments = new List <DebtPayment>();
if (initialSnowballStart == null)
{
initialSnowballStart = DateTime.Now;
}
double TotalIntrest = 0;
foreach (Debt d in Debts)
{
d.Balance = d.OriginalBalance;
if (d.FirstPaymentDate < cur)
{
cur = d.FirstPaymentDate;
}
}
while (GetTotalBalance() > 0)
{
double curExtra = cur >= initialSnowballStart && Snowball ? initialSnowballPayment : 0;
if (Snowball)
{
foreach (ExtraPayment ep in ExtraPayments.Where(x => x.Enabled == true))
{
curExtra = curExtra + ep.IsItTimeToApply(cur.Month, cur.Year);
}
}
List <Debt> debtOrder = new List <Debt>();
switch (approach)
{
case SnowballApproaches.MyOrder:
debtOrder = Debts.ToList();
break;
case SnowballApproaches.LowestBalanceFirst:
debtOrder = Debts.OrderBy(x => x.OriginalBalance).ToList();
break;
case SnowballApproaches.HighestInterestFirst:
debtOrder = Debts.OrderByDescending(x => x.IntrestRate).ToList();
break;
}
foreach (Debt d in debtOrder)
{
if (d.Balance > 0 && d.Enabled && cur >= d.FirstPaymentDate)
{
double extra = 0;
if (d.Balance >= curExtra)
{
extra = curExtra;
curExtra = 0;
}
else
{
extra = d.Balance;
curExtra = curExtra - d.Balance;
}
PaymentResult pr = Debt.CalculateBalanceWithPayment(d.IntrestRate, d.Payment + extra, d.Balance, cur.Year, cur.Month);
d.Balance = pr.NewBalance;
TotalIntrest += pr.Interest;
DebtPayment dp = new DebtPayment();
dp.Intrest = Math.Round(pr.Interest, 2);
dp.Balance = Math.Round(pr.NewBalance, 2);
dp.Name = d.Name;
dp.Payment = Math.Round(d.Payment + extra, 2);
dp.ExtraPaid = extra;
dp.Principal = Math.Round(pr.Principal, 2);
dp.TotalBalance = Math.Round(GetTotalBalance(), 2);
dp.TotalInterestPaid = Math.Round(TotalIntrest, 2);
dp.Date = cur.Month.ToString() + "/" + cur.Year.ToString();
DebtPayments.Add(dp);
if (Snowball)
{
if (d.Balance == 0)
{
Debt snowballTo = new Debt();
snowballTo.Balance = 9999999999;
foreach (Debt dm in Debts)
{
if (dm.Enabled && dm.Balance < snowballTo.Balance && dm.Balance > 0)
{
snowballTo = dm;
}
}
initialSnowballPayment += d.Payment;
//snowballTo.Payment += d.Payment;
}
}
}
}
cur = cur.AddMonths(1);
if (cur.Year > 2050)
{
break;
}
}
AccumulatorCollection acPrincipal = new AccumulatorCollection();
AccumulatorCollection acInterest = new AccumulatorCollection();
for (int x = 0; x < DebtPayments.Count; x++)
{
acInterest.AddTo(DebtPayments[x].Date, DebtPayments[x].Intrest);
acPrincipal.AddTo(DebtPayments[x].Date, DebtPayments[x].Principal);
}
for (int x = 0; x < DebtPayments.Count; x++)
{
DebtPayments[x].TotalMonthlyInterest = acInterest.GetMonthAccumulation(DebtPayments[x].Date);
DebtPayments[x].TotalMonthlyPrincipal = acPrincipal.GetMonthAccumulation(DebtPayments[x].Date);
}
TimeSpan finishedProcess = DateTime.Now - startProcess;
Debug.WriteLine($"Process Took: {finishedProcess.TotalSeconds} seconds");
return(DebtPayments);
}