/**
 * Write a description of class MonthlyPayment here.
 * Added 8/9/10: Prompts user to determine what kind of calculation should be done; monthly payment or principle
 * Prompts user to enter house cost, down payment, interest rate and number of payments then returns the monthly payment amount.
 * Prompts user to enter monthly payment, down payment, interest rate and number of payments then returns the principle amount.
 * Added 8/16/10: Repeats until Q is entered  
 * Added 8/16/10: Verifies valid values for M and P paths
 * @Michele
 * @3.0
 */
import java.util.Scanner;
import java.text.*; 
public class MonthlyPayment
{
    // variables passed to calc function
    private double houseCost;
    private int downPayment;
    private double rate;
    private int numOfPayments;
    private double monthlyPayment;
       
  public static void main(String [] args)
  {
   char inputType; 
   Scanner keyInput = new Scanner(System.in);
   System.out.print("Enter 'P' to calculate principle, 'M' to calculate monthly payment or 'Q' to quit: ");
   inputType = keyInput.next().charAt(0);
       int inputHouse = 0; 
       int inputMonthlyPayment = 0;
       int inputDown = 0;
       double inputRate = 0;
       int inputNum = 0;
       MonthlyPayment mp = new MonthlyPayment (); 
   while (inputType != 'Q' && inputType != 'q')
   {
      if (inputType != 'M' && inputType != 'm' && inputType != 'P' && inputType != 'p')
      {
        System.out.println("Please enter a valid value 'M', 'P' or 'Q': ");
        inputType = keyInput.next().charAt(0);
        keyInput.nextLine();
      }
      if (inputType == 'M' || inputType == 'm')
      {
         do
         {
            System.out.print("Enter the house cost: ");
            if (keyInput.hasNextInt())
            {
                inputHouse = keyInput.nextInt();
            }
            keyInput.nextLine();
            if (inputHouse <= 0)
            {
                System.out.println("invalid value");
            }
         } // end do
        while (inputHouse <= 0);
      } //end if m
      if (inputType == 'P' || inputType == 'p')
      {
         do
         {
            System.out.print("Enter the monthly payment: ");
            if (keyInput.hasNextInt())
                {
                 inputMonthlyPayment = keyInput.nextInt();
                }
            if (inputMonthlyPayment < 0 || inputMonthlyPayment > 999999)
            {
                System.out.println("Invalid value");
            }
         } // end do
        while  (inputMonthlyPayment < 0 || inputMonthlyPayment > 999999);
      } //end if p
     
      do
      {
        System.out.print("Enter the down payment: ");
        if (keyInput.hasNextInt())
            {
                inputDown = keyInput.nextInt();
            } 
        keyInput.nextLine();
        if (inputDown <= 0 || inputDown > inputHouse)
            {
                System.out.println("invalid value");
            }
      } // end do
      while (inputDown <= 0 || inputDown > inputHouse);     
        
      do
      {
        System.out.print("Enter the interest rate: (ex 7.5) ");
        if (keyInput.hasNextDouble())
            {
                inputRate = keyInput.nextDouble();
            }
        keyInput.nextLine(); 
        if  (inputRate < 0 || inputRate > 100)
            {
                 System.out.println("Invalid value");
            }  
      } // end do
      while (inputRate < 0 || inputRate > 100);
 
        
      do
      {
         System.out.print("Enter the number of monthly payments: ");
         if (keyInput.hasNextInt())
            {
                inputNum = keyInput.nextInt();
            }
         keyInput.nextLine();
         if (inputNum < 0 || inputNum > 99999)
            {
                System.out.println("Invalid value");
            }
            else
            {               
               keyInput.nextLine();
            } 
      } // end do
      while (inputNum < 0 || inputNum > 99999);
    
      if (inputType == 'M' || inputType == 'm')
      {
           // Defines new decimal format using java.text.* class
           DecimalFormat twoDigit = new DecimalFormat("#,##0.00");//formats to 2 decimal places
 
           mp.setHouseCost(inputHouse);
           mp.setDownPayment(inputDown);
           mp.setRate(inputRate);
           mp.setNumOfPayments(inputNum);   
           mp.calcPayment();
             
           // Returns Monthly payment formatted to 2 decimal places
           System.out.println("Your monthly payment is: $" + twoDigit.format(mp.getMonthlyPayment()));
      }  
 
      if (inputType == 'P' || inputType == 'p') 
      {
               mp.setDownPayment(inputDown);
               mp.setRate(inputRate);
               mp.setNumOfPayments(inputNum);   
               mp.setPayment(inputMonthlyPayment);
               mp.calcPrinciple();
    
               // Defines new decimal format using java.text.* class
               DecimalFormat twoDigit = new DecimalFormat("#,##0.00");//formats to 2 decimal places
       
               // Returns Principle amount formatted to 2 decimal places
               System.out.println("Your principle amount is: $" + twoDigit.format(mp.getPrinciple()));
      } // ends if  
        
        System.out.print("Enter 'P' to calculate principle, 'M' to calculate monthly payment or 'Q' to quit: ");
      inputType = keyInput.next().charAt(0);    
 
    }  //End while !q
  } // end main
  public MonthlyPayment()
    {// Initialize variables
       houseCost = 0;
       downPayment = 0;
       rate = 0.00;
       numOfPayments = 0;
       monthlyPayment = 0.00;
    }
  public void calcPayment () // void because it doesn't return value, calculates payment
  {
    monthlyPayment = (((houseCost - downPayment)*(.01*rate/12))/(1-Math.pow((1+(.01*rate/12)),-(numOfPayments))));
  }
  public void calcPrinciple () // void because it doesn't return value, calculates principle amount
  {
     houseCost = downPayment+(12*monthlyPayment)*(1-Math.pow((1+(.01*rate/12)),-(numOfPayments)))/(.01*rate); 
  }   
  public void setHouseCost (int costIn) // sets user entered value to costIn
  {
     houseCost = costIn;
  }
  public void setDownPayment (int downPayIn) // sets user entered value to downPayIn
  {
    downPayment = downPayIn;
  }
  public void setRate (double rateIn) // sets user entered value to rateIn
  {
    rate = rateIn;
  }
  public void setNumOfPayments (int numOfPaymentsIn) // sets user entered value to numOfPaymentsIn
  {
    numOfPayments = numOfPaymentsIn;
  }
  public void setPayment (double paymentIn) // sets user entered value to paymentIn
  {
    monthlyPayment = paymentIn;
  }   
  public double getMonthlyPayment () // returns the calculated monthly payment
  {
    return monthlyPayment;
  }
  public double getPrinciple () // returns the calculated priciple amt
  {
    return houseCost;
  }
} // ends class