import java.io.*;
import java.math.*;
import java.text.DecimalFormat;

public class Amortization {

	private double loanAmount;
	private double interestRate;
	private double loanBalance;
	private double term;
	private double payment;
	private int loanYears;

	public Amortization(double loan, double rate, int years) {
		this.loanAmount = loan;
		this.loanBalance = loan;
		this.interestRate = rate;
		this.loanYears = years;

		calcPayment();
	}

	private void calcPayment() {
		this.term = Math.pow(interestRate / 12 + 1, loanYears * 12);
		this.payment = (loanAmount * (interestRate / 12.0) * term) / (term - 1);
	}

	public int getNumberOfPayments() {
		return (loanYears * 12);
	}

	public double getLoanAmount() {
		return loanAmount;
	}

	public double getInterestRate() {
		return interestRate;
	}

	public int getLoanYears() {
		return loanYears;
	}

	public void saveReport(String filename) throws FileNotFoundException {
		DecimalFormat df = new DecimalFormat("0.00");
		File file = new File(filename);
		PrintWriter pw = new PrintWriter(file);
		pw.println("Monthly Payment: $" + df.format(payment));
		pw.println("Month\tInterest\tPrincipal\tBalance");
		pw.println("-----------------------------------------------");
		for (int i = 0; i < getNumberOfPayments(); i++) {
			double interest = interestRate / 12.0
					* loanBalance;
			double principal = payment - interest;
			loanBalance -= principal;
			pw.println((i + 1) + "\t" + df.format(interest) + "\t\t"
					+ df.format(principal) + "\t\t" + df.format(loanBalance));
		}

		pw.close();

	}
}