/**
 * @author Max Tessier
 * @version NetBeans IDE 11.2
 * @course CPSC 1302
 */

public class Main {
    //below I instantiate all variables. I tried after the constructor but it wasn't working.
    //This is probably not 'ideal' per coding conventions but it works
    private static final double PERIODYEAR = 12;
    private double lifeYear;
    private double initialLoan;
    private double intRate;
    private static final double INVALID = -1.0;
    private double periodTotal;
    private double monthRate;
    private double monthExp;
    private double division;
    private double monthPay;
    private double interestPaid = 0;
    private double interestPaidz = 0;
    private double currentBal;
    private double currentBalz;
    private double intMonth;
    private double intMonthz;
    private double monthBal;
    private double monthBalz;

    public Main(){  //empty constructor

    }

    public Main( double Balance, double Interest, double years){ //constructor 3 args
        initialLoan = Balance;
        intRate = Interest;
        lifeYear = years;
        currentBal = initialLoan;
        currentBalz = initialLoan;
        periodTotal = PERIODYEAR*lifeYear;
        monthRate = intRate/PERIODYEAR;
        monthExp = 1+monthRate;
        division = Math.pow(monthExp,periodTotal);
        monthPay = initialLoan * (monthRate + (monthRate / (division-1)));

    for(int i=0; i<periodTotal; i++){  //for loop to calculate rates per month
            intMonth = monthRate * currentBal;
            interestPaid = interestPaid + intMonth;
            monthBal = monthPay - intMonth;
            currentBal = currentBal - monthBal;
        }

    for (int k=0;k<=periodTotal - 1 ; k++){
                intMonthz = monthRate * currentBalz;
                interestPaidz = interestPaidz + intMonthz;
                monthBalz = monthPay - intMonthz;
                currentBalz = currentBalz - monthBalz;

}
    }


    public double getMonthlyPayment(){ //delivers the base monthly payment, identical every month
        return Math.round(monthPay *100.0) / 100.0;
    }
    public double getTotalInterest(){ //delivers total paid towards interest, at the end of the loan
        return Math.round(interestPaid * 100.0) / 100.0;
    }
    public double getTotalPayments(){ //delivers total paid, monthly payment * # of payments
        return Math.round((monthPay*periodTotal)* 100.0) / 100.0;
    }
    public double getAmount(String month, String payment){ //different deliverable, based on input
        if (month.equalsIgnoreCase("first")){ // first month deliverables, based on 2nd input
            if (payment.equalsIgnoreCase("interest")){
                return Math.round((monthRate * initialLoan) * 100.0) / 100.0 ;
            }
            else if (payment.equalsIgnoreCase("principal")){
                return Math.round((monthPay - (monthRate*initialLoan))* 100.0) / 100.0;
            }
            else if (payment.equalsIgnoreCase("balance")){
                return Math.round((initialLoan-(monthPay - (monthRate*initialLoan))) * 100.0) / 100.0;
            }
            else {
                return INVALID;
            }
        }
        else if (month.equalsIgnoreCase("last")){ // calculating all values to last month, instead of entire loan


                    if (payment.equalsIgnoreCase("interest")){
                return Math.round(intMonthz * 100.0) / 100.0;
            }
                    else if (payment.equalsIgnoreCase("principal")){
                return Math.round((monthPay - intMonthz) * 100.0 ) / 100.0;
            }
                    else if (payment.equalsIgnoreCase("balance")){
                return Math.round(currentBalz * 100.0) / 100.0;
            }
                    else {
                return INVALID;
            }
                }


        else { //in the case the first input was invalid, returns invalid
            return INVALID;
        }

}
}