//********************************************************************
//
// BankLoan.java
// Program title: Bank Loan Calculator
//
//********************************************************************
//
// Program Description and Design Overview:
//      
//
// Input Requirements:
//      Initial loan balance		float
//		Annual interest rate		float
//		Total number of months		integer
//		1st month to be calculated	integer
//		2nd month to be calculated	integer
//		3rd month to be calculated	integer
//		4th month to be calculated	integer
//
// Output Requirements:
//      Program title message followed by a blank line
//		Input prompt messages that ask the user to input the three balues for the laon terms
//		An output message that shows the monthly payment with money value formatted as currency followed by blank line
//		An input prompt message that askes the user for the 1st month
//		An outpot message that shows the inputted month value and balance remaining after that month's payment has been made, with money value formatted as currnecy followed by an extra blank line
//		Prompt and output messages for 2nd, 3rd, and 4th months
// 
//
// Program Preconditions:
//		The user must typed valid numeric values in response to all input prompt messages.
//      
//
//********************************************************************

import cs1.Keyboard;			// imports the Keyboard class so the program can accept input from the keyboard
import java.text.NumberFormat;	// imports the NumberFormat class so that outputs may be diplayed in currency format

public class BankLoan
{
   //-----------------------------------------------------------------
   //  A comment that must be replaced by comment(s) describing the    //  program's main method.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
   	
   	float StartBal, 	//the initial loan balance
   		APR, 			//the annual percentage rate
   		monthlyRate,	//the monthly percentage rate
   		monthlyPmt,		//the amount of the monthly payment
		remainingBal;	//the remaining balance after "x" (curMonth) number of payments have been made
   	int NumMonths,		//the total number of months payments
   		curMonth = 0;
   	
   	System.out.println ("Bank Loan Calculator");	//Prints program title
   	System.out.println ();
   	
   	System.out.print ("Enter initial loan balance in dollars and cents, e.g., 10575.50: ");	// prompts user for initial loan balance
   	StartBal = Keyboard.readFloat();	//inputs user response to variable StartBal for the initial loan balance
   	
   	System.out.print ("Enter annual interest rate as a percent value (with decimal but no % sign): "); // prompts user for annual interest rate
   	APR = Keyboard.readFloat(); // inputs user response to variable APR for the annual percentage rate
   	
   	monthlyRate = ((APR / 100) / 12); // computes the monthly interest rate to variable monthlyRate
   	
   	System.out.print ("Enter total number of months for the loan: "); //prompts user for total number of months (payments) for the loan
    NumMonths = Keyboard.readInt();	//inputes user response to variable NumMonths for the number of payments
    
    monthlyPmt = (float)((monthlyRate * StartBal) / (1.0-(Math.pow((1.0 + monthlyRate),(curMonth-NumMonths)))));	//calculates the monthly payment
    
    NumberFormat currency = NumberFormat.getCurrencyInstance();	//defines the variable currency as a format of converting text to currency format
    
    System.out.print ("Monthly Payment : " + currency.format(monthlyPmt) );  //outputs the monthly payment on the screen in currency format
    
    System.out.println ();	//prints extra blank line
    System.out.println ();	//prints extra blank line
    
    System.out.print ("Enter payment number of 1st month to be calculated: "); //prompts user for the payment number of the first month to be calculated
    curMonth = Keyboard.readInt();	//stores user input into the integer variable curMonth

    remainingBal=monthlyPmt * ((float)(1.0-((Math.pow((1.0+monthlyRate),(curMonth - NumMonths)))))/monthlyRate);	//calculates the remaining balance and stores it in the float variable remainingBal
    System.out.println ("Balance remaining after month " + curMonth + " payment = " + currency.format(remainingBal));	//prints the remaining balance after the 1st number of months have been paid
    
    System.out.println ();	//prints extra blank line
    
    System.out.print ("Enter payment number of 2nd month to be calculated: "); //prompts user for the payment number of the 2nd month to be calculated
    curMonth = Keyboard.readInt();	//stores user input into the integer variable curMonth

    remainingBal=monthlyPmt * ((float)(1.0-((Math.pow((1.0+monthlyRate),(curMonth - NumMonths)))))/monthlyRate);	//calculates the remaining balance and stores it in the float variable remainingBal
    System.out.println ("Balance remaining after month " + curMonth + " payment = " + currency.format(remainingBal));	//prints the remaining balance after the 2nd number of months have been paid
    
    System.out.println ();	//prints extra blank line
    
    System.out.print ("Enter payment number of 3rd month to be calculated: "); //prompts user for the payment number of the third month to be calculated
    curMonth = Keyboard.readInt();	//stores user input into the integer variable curMonth

    remainingBal=monthlyPmt * ((float)(1.0-((Math.pow((1.0+monthlyRate),(curMonth - NumMonths)))))/monthlyRate);	//calculates the remaining balance and stores it in the float variable remainingBal
    System.out.println ("Balance remaining after month " + curMonth + " payment = " + currency.format(remainingBal));	//prints the remaining balance after the 3rd number of months have been paid
    
    System.out.println ();	//prints extra blank line
    
    System.out.print ("Enter payment number of 4th month to be calculated: "); //prompts user for the payment number of the fourth month to be calculated
    curMonth = Keyboard.readInt();	//stores user input into the integer variable curMonth

    remainingBal=monthlyPmt * ((float)(1.0-((Math.pow((1.0+monthlyRate),(curMonth - NumMonths)))))/monthlyRate);	//calculates the remaining balance and stores it in the float variable remainingBal
    System.out.println ("Balance remaining after month " + curMonth + " payment = " + currency.format(remainingBal));  //prints the remaining balance after the 4th number of months have been paid
   	
   	System.out.println ();	//prints extra blank line
   	
   
   } //end main

} // end class BankLoan