import javax.swing.JOptionPane;
import java.text.DecimalFormat;

public class MortgageCalculator2
{
    // Move answer to a higher scope so that many functions can see and manipulate it
    private static double answer;
	
    public static void main(String[] args)
    {
        //declare variables
        double principal, interest, monthlyInterest;
        int term, numbPayments;

           
        //calling methods
        principal = getPrincipal();
        interest = getInterest()/100;
        term = getTerm();
        monthlyInterest = interest/12;
        numbPayments = term*12;
        answer = (principal*(monthlyInterest*Math.pow((1+monthlyInterest),numbPayments)))/(Math.pow((1+monthlyInterest),numbPayments) -1);
        output();
        finish();

    }
   
    //The getPrincipal() method will ask the user to input the principal amount
    public static double getPrincipal()
    {
        //declare method variable
        double principal = 0.0;
       
        // Don't forget to set principal to what was entered
        String principle = JOptionPane.showInputDialog(null, "Enter the Mortgage amount\n(do not use commas or dollar signs)\n or click Cancel to exit:");
        principal = Double.parseDouble(principle);
		
        return principal;
    }
   
    //The getInterest() method will retrieve the interest amount
    public static double getInterest()
    {
        //declare method variable
        double interest = 0.0;
        boolean done = false;
       
        //loop while not done
        while (!done)
        {
            try
                {
                    String rate = JOptionPane.showInputDialog(null, "Enter the interest rate\n(do not use the percentage sign)");
       
                    interest = Double.parseDouble(rate);
                   
                    //test for interest rate amount
                    if (interest<0.0) throw new NumberFormatException();
                    else done = true;
                }
                catch(NumberFormatException e)
                {
                    JOptionPane.showMessageDialog(null, "Please enter an interest rate.", "Error",JOptionPane.INFORMATION_MESSAGE);
                }
                }        
        return interest;
    }
   

    //the getTerm() method will get the term length of the loan
    public static int getTerm()
   
    {
        //declare method variable
        int term = 0;
       
        // Again, make sure you set term to the value entered
        String number = JOptionPane.showInputDialog(null, "Enter the length of mortgage term, use numbers only:");
        term = Integer.parseInt(number);
	   
        return term;
    }
   
    //the output() method will display the monthly payment for the loan
    public static void output()
    {
        // Change the pattern here to only show numbers and never leading zeros.
        DecimalFormat twoDigits = new DecimalFormat("$#,##0.00");
        JOptionPane.showMessageDialog(null,"Your Monthly Payment is:" + twoDigits.format(answer));
               
   
    }
   
    //the finish() method ends the program
    public static void finish()
    {
        System.exit(0);
    }
}