/// <summary>
/// Расчитывать выплаты.
/// X = (S*p) / (1-(1+p)^(1-m))
/// X - размер аннуитетного платежа;
/// S - сумма кредита;
/// p - 1/12 годовой процентной ставки, выраженная в сотых долях;
/// ^ - означает в степени;
/// m - срок кредита, в месяцах.
/// </summary>
/// <param name="amount">Объем долга.</param>
/// <param name="interestRate">Процентная ставка.</param>
/// <param name="loanTerm">Срок кредита(в месяцах).</param>
/// <returns>Выплаты по кредиту.</returns>
public IEnumerable<Payment> Calculate(
Amount amount,
InterestRate interestRate,
LoanTerm loanTerm)
{
if (amount == null || interestRate == null || loanTerm == null)
{
throw new ArgumentException("Bad params for calculation");
}
var payments = new List<Payment>();
var totalBalanceOwed = amount.Value;
int number = 0;
while (totalBalanceOwed > 0)
{
var loanPayment = totalBalanceOwed / (loanTerm.Value - number);
var percentPayment = totalBalanceOwed * interestRate.Value / (100 * 12);
totalBalanceOwed -= loanPayment;
var payment = new Payment(number, percentPayment, loanPayment, totalBalanceOwed);
payments.Add(payment);
number++;
}
return payments;
}
/// <summary>
/// Конструктор класса.
/// </summary>
/// <param name="payment">Данные об оплате.</param>
public PaymentViewModel(Payment payment)
{
this.payment = payment;
}
