/**
 * Copyright (c) Wishnu Prasetya, 2009.
 */

package Hypotheek;

import java.util.*;
import static Hypotheek.Util.* ;

/**
 *
 * @author Wishnu Prasetya
 */
public class Hypotheek  {

	static final int MAX_LOAN_DURATION = 30 * 12 ;
    static final int MAX_LOAN = euro2cent(21000000) ;
    static final int MAX_INTEREST_RATE = 100 * 100 ; // 100%
	
	/**
	 * Max. duration of the hypotheek in month.
	 */
	int duration = MAX_LOAN_DURATION ;
		
	/**
	 * How much money you borrow for this hypotheek. This is in Euro-cent.
	 */
	int loan = 100 * 100000 ; // 100 K
	
	/**
	 * The annual interest rate on this hypotheek. This is expressed in 0.01 %.
	 * So an interest of 3.33 % would be encoded by 333 integer.
	 */
	int interestRate = 100 * 5 ; // 5%

    /**
     * From the monthly amount used to pay back the loan we first
     * deduct the loan's interest. The "rest" is normally paid to
     * reduce the loan. However, as in the spaar-hypotheek we
     * can instead "save" this money against the same interest rate
     * as the rate of the hypotheek. The saved money is used to
     * pay back the loan at the end of the loaning period. In the
     * Dutch tax system this gives a certain benefit.
     *
     * <p>With this variable we can specify how much percent of the
     * "rest" meant above will saved using the spaar-hyp scheme. If
     * 100%, all will be saved. With 50%, then only half will be saved.
     * Of course in a spaar-hyp we normally save 100%, though with
     * this option we can hypothetically
     * analyze a semi spaar-hyp.
     *
     * <p>Percentage will be specified in 0.01 % units.
     */
     int percentageToSave = 0 ;

	/**
	 * Your annual income in Euro.
	 */
	int income = 100* 20000 ;

    /**
     * Your age.
     */
    int age = 30 ;
	
	/**
	 * The amount of money you want to pay monthly to payback your hypotheek. 
	 * This is the bruto amount. That is the amount BEFORE tax. The netto
	 * amount you pay should be less than this, because of the tax reduction
	 * on the interest you pay.
	 */
	int monthlyPayment = 100 * 500 ;

    /**
     * The overhead cost of purchasing the house. This includes the 6%
     * overdrachtsbelastix (transfer tax). The usual estimation of the total
     * purchase overhead is 10%. Usually this overhead is financed from
     * the loan itself. While this is ok, the interest over this overhead
     * is not tax deductible.
     */
    int purchaseCostPercentage = 9 * 100 ; // 9%

	/**
     * Your bank may require you to have a life insurance so that if
     * you die, some sufficient amount of money is paid (by the insurance)
     * to your family and hence the risk that your family cannot pay 
     * back the rest of the loan is minimized. We will not support a
     * calculation of this premium because this depends on the market
     * of insurance, as well as your specific agreement with the bank.
     * 
     * However assuming you can find out how much your premium will be,
     * or make an estimate, then it can be included in our calculation.
     * However, for simplicity we will just assume that this premium
     * will remain constant.
     * In general this is not the case. It depends on your age and your
     * health conditions. But again this is also something that depends on
     * the insurance market.
     *
     * This premium is expressed in monthly premium.
     * By default this will be set to 0.
     */
    int lifeInsurancePremium = 0 ;

    /**
     * The used income-tax system.
     */
    InkomenBelasting incomeTaxSystem = new InkomenBelasting2009() ;

    /**
     * Tax regulation concerning so-called Eigen Woning Forfait.
     */
    EigenWoningForfait EWforfait = new EigenWoningForfait2007() ;
    
    /**
     * For profit calculation. Expressed in percent, in 0.01 % units.
     * So a growth of 2.1 % should be represented by 210.
     */
    int assumedHousePriceIncrRate = 200 ; // 2% growth




	public Hypotheek() { super() ; }




	public void setDuration(int duration) {
		assert duration > 0 : "PRE" ;
		assert duration <= MAX_LOAN_DURATION : "PRE" ;
		this.duration = duration;
	}

	public void setLoan(int loan) {
		assert loan > 0 : "PRE" ;
		assert loan <= MAX_LOAN : "PRE" ;
		this.loan = loan;
	}

	public void setIterest(int interestRate) {
		assert interestRate >= 0 : "PRE" ;
		assert interestRate <= MAX_INTEREST_RATE : "PRE" ;
		this.interestRate = interestRate ;
	}

	public void setIncome(int income) {
		assert income > 0 : "PRE" ;
        assert income <= MAX_LOAN : "PRE" ;
		this.income = income;
	}

	public void setMonthlyPayment(int monthlyPayment) {
		assert monthlyPayment > 0 : "PRE" ;
        assert monthlyPayment <= MAX_LOAN : "PRE" ;
		this.monthlyPayment = monthlyPayment;
	}

    static public int MAX_AGE = 200 ;

    public void setAge(int age) {
        assert age >= 0 : "PRE" ;
        assert age <= MAX_AGE : "PRE" ;
        this.age = age ;
    }

    public void setAssumedHousePriceIncrRate(int rate) {
        assert rate >= 0 : "PRE" ;
		assert rate <= MAX_INTEREST_RATE : "PRE" ;
        assumedHousePriceIncrRate = rate ;
    }

    public void setPercentageToSave(int p){
        assert p >= 0 : "PRE" ;
        assert p <= 100 * 100 : "PRE" ;
        percentageToSave = p ;
    }

    public void switchToPureSpaarHypotheek() {
        percentageToSave = 100 * 100 ;
    }

    public void setPurchaseCostPerctage(int pc){
        assert pc >= 0 : "PRE" ;
        assert pc <= 100*100 : "PRE" ;
        purchaseCostPercentage = pc ;
    }

    public void setLifeInsurancePremium(int premium){
        assert premium >= 0 : "PRE" ;
        lifeInsurancePremium = premium ;
    }
    
	/**
     * To hold some data structures to hold calculation results.
     */
	public class Result {
        List<Integer> loanPayBacks = new LinkedList<Integer>() ;
        List<Integer> interestPayments = new LinkedList<Integer>() ;
        List<Integer> remainingLoan = new LinkedList<Integer>() ;
        List<Integer> lifeInsurancePremium = new LinkedList<Integer>() ;

        /**
         * For the spaar-hypotheek scheme.
         */
        List<Integer> saved = new LinkedList<Integer>() ;

        int totSaved = 0 ;

        /**
         * This hold the total money we have saved up to the corresponding
         * month, including the interest on the saved money.
         */
        LinkedList<Integer> progressTotalSaved = new LinkedList<Integer>() ;

        List<Integer> taxReductions = new LinkedList<Integer>() ;

        int remaining = loan ;

        // int monthlyInterestRate = div(interestRate,12) ;
        // boolean feasible = false ;

        // Some overall cummulative statistics
        int totPaidBruto ;
        int totPaidNetto ;
        int totInterest ;
        int totLoanPaidBack ;
        int totTaxReduction ;
        int projectedHouseValue ;
        int profit ;

        // Some yearly cummulative statistics
    }

	/**
	 * Calculate the monthly interest on the loan of x euro-cent, using the interest rate
	 * of this hypotheek. The interest will be expressed in euro-cent.
	 */
	private int calcMonthlyInterest(int x) {
        int monthlyInterestRate = div(interestRate,12) ;
        float irate = toFloat(monthlyInterestRate) / 100f ;
		return toInt(calcPercentage(irate,x)) ;
	}
	
	private boolean isMonthlyPaymentSufficient(int remainingLoan) {
		int interest = calcMonthlyInterest(remainingLoan) ;
        //System.out.println(">>> remaining loan = " + remainingLoan) ;
        //System.out.println(">>> monthly payment = " + monthlyPayment) ;
        //System.out.println(">>> interest = " + interest) ;
		return monthlyPayment >= interest + lifeInsurancePremium ;
	}

    public int getOverheadCost(){
        return toInt(calcPercentage(div(purchaseCostPercentage,100),loan)) ;
    }


    /**
     * Since we assume that there may be some overhead cost when we
     * purchase a house, and that this cost is paid from the loan,
     * the actual house-price when it is purchased is then the loan
     * - this cost.
     */
    public int getHousePurchaseValue(){
        return loan - getOverheadCost() ;
    }

    public int getEigenWoningforfait() {
        return EWforfait.calc(getHousePurchaseValue()) ;
    }


	public Result calculate() {

        Result R = new Result() ;

		boolean feasible = isMonthlyPaymentSufficient(loan) ;
		
		if (!feasible) return null ;
		
		int t = 1 ;
	
		while (R.remaining - R.totSaved>0 && t<=duration) {
			
			assert isMonthlyPaymentSufficient(R.remaining) ;
			
			int interest = calcMonthlyInterest(R.remaining) ;
			int loanPayment = monthlyPayment - interest - lifeInsurancePremium ;

            int toSave = toInt(toFloat(percentageToSave)/10000f * toFloat(loanPayment)) ;
            loanPayment = loanPayment - toSave ;

            if (R.remaining < loanPayment + toSave) {
                loanPayment = R.remaining ;
                toSave = 0 ;
            }
            else if (R.remaining - R.totSaved < loanPayment + toSave) {
                loanPayment = R.remaining - R.totSaved ;
                toSave = 0 ;
            }

            R.remaining = R.remaining - loanPayment ;
            int interestOnSaving = calcMonthlyInterest(R.totSaved) ;
            R.totSaved += interestOnSaving + toSave ;
            //System.out.println(">>> (" + t + ") " + R.totSaved) ;

			R.interestPayments.add(interest) ;
			R.loanPayBacks.add(loanPayment) ;
			R.remainingLoan.add(R.remaining) ;
            R.saved.add(toSave) ;
            R.progressTotalSaved.add(R.totSaved) ;
			
			t++ ;
		}	
		calcTaxReduction(R) ;
		calcCummulativeStats(R) ;
         
        return R ;
	}
	
	private void calcTaxReduction(Result R) {

       List<Integer> interestPayments = new LinkedList(R.interestPayments) ;
       int N = interestPayments.size() ;
       int K = 0 ;
       if (N % 12 != 0) K = 12 - (N % 12) ;
       for (int i=0; i<K; i++) interestPayments.add(0);

       // we'll also keep track of part of the overhead cost paid from loan
       // which is not paid back yet, since this influences tax deduction
       int overheadCost = getOverheadCost() ;
       int pure_hypotheek_loan_base = getHousePurchaseValue() ;

       int assumed_income = income + getEigenWoningforfait() ;

       int cummulativeAnnualInterestPayment = 0 ;
       int t = 1 ;

       //System.out.println(">>> " + interestPayments.size()) ;
       //System.out.println(">>> " + R.remainingLoan.size()) ;

       for (int interest : interestPayments) {
           int tax_deductible_interest = interest ;
           if (interest > 0) {
             int remaining = R.remainingLoan.get(t-1) ;
             if (remaining > pure_hypotheek_loan_base) {
                   int remaining_non_tax_deductibe_loan = remaining - pure_hypotheek_loan_base ;
                   int tax_non_deductible_interest = calcMonthlyInterest(remaining_non_tax_deductibe_loan) ;
                   tax_deductible_interest = Math.max(0, tax_deductible_interest - tax_non_deductible_interest) ;
             }
           }
           cummulativeAnnualInterestPayment += tax_deductible_interest ;
            // End of a year, calculate tax reduction:
           	if (t % 12 == 0) {
                // tax reduction over a year:
                int current_age = age + t/12 ;
				int taxReduction = incomeTaxSystem.calcHypBelastingAftrek(assumed_income, current_age, cummulativeAnnualInterestPayment) ;

                int numOfMonth = 12 ;
                if (t>N) numOfMonth = N % 12 ;
				int mothlytaxReduction = div(taxReduction,numOfMonth) ;
				for (int m=0; m<numOfMonth; m++) R.taxReductions.add(mothlytaxReduction) ;
				cummulativeAnnualInterestPayment = 0 ;
			}
			t++ ;
       }
    }

    public List<Integer> calcYearlyCummulativeProgressOfLoanPaid(Result R) {

        return groupAccumulate(R.loanPayBacks,12) ;

    }

    public LinkedList<Integer> calcYearlyCummulativeProgressOfSaving(Result R) {
        LinkedList<Integer> progress = new LinkedList<Integer>() ;
        int N = R.progressTotalSaved.size() ;
        int Y = N / 12 ;
        int m = 0 ;
        while (m<N) {
            m++ ;
            if (m % 12 == 0) progress.add(R.progressTotalSaved.get(m-1)) ;
        }
        if (N % 12 > 0) progress.add(R.progressTotalSaved.getLast()) ;
        return progress ;
    }

     public List<Integer> calcYearlyCummulativeProgressOfTaxReduction(Result R) {

        return groupAccumulate(R.taxReductions,12) ;

    }

	private void calcCummulativeStats(Result R) {
        
        R.totLoanPaidBack = loan - R.remaining ;
        R.totPaidBruto = 0 ;
        for (int i : R.interestPayments) R.totPaidBruto += i ;
        for (int a : R.loanPayBacks) R.totPaidBruto += a ;
        for (int s : R.saved) R.totPaidBruto += s ;
        R.totInterest = 0 ;
        for (int i : R.interestPayments) R.totInterest += i ;
        R.totTaxReduction = 0 ;
        for (int tr : R.taxReductions) R.totTaxReduction += tr ;
        R.totPaidNetto = R.totPaidBruto - R.totTaxReduction ;

        int actualDuration = R.interestPayments.size() ;
        
        //System.out.println(">>> " + actualDuration) ;
        
        float growth = 1f + toFloat(assumedHousePriceIncrRate) / 10000f ;
        float projectedHouseValue_ = cummulativeGrowth(getHousePurchaseValue(),growth,toFloat(actualDuration)/12f) ;
		
		R.projectedHouseValue = toInt(projectedHouseValue_) ;
		R.profit = R.projectedHouseValue -  R.totPaidNetto - (R.remaining - R.totSaved) ;
    }

	/**
	 * Convert months to years, rounded to 1 decimal.
	 */
	private float month2year(int months) {
		float j = Math.round(10.0 * ((float) months) / 12f ) ;
		return j/10f ;

	}
	
	
	public String printGenStatistics(Result R) {

        StringBuffer o = new StringBuffer() ;
        int W = 31 ;
        int WD = 12 ;

		o.append("GEGEVENS:\n") ;

		o.append(leftAlign("** Lening =",W) + showEuro(loan,WD) + " eur.\n") ;

		o.append(leftAlign("** Max. leenperiode =",W) + rightAlign(""+duration,WD-3) + "    maanden ("
					+ month2year(duration) + " jaar)\n") ;
		
		o.append(leftAlign("** Rente =",W) + showEuro(interestRate,WD) + " %\n") ;

        if (lifeInsurancePremium>0)
            o.append(leftAlign("** Premie levensverz. =",W) + showEuro(lifeInsurancePremium,WD) + " eur. (per maand)\n") ;

		o.append(leftAlign("** Maandl. bruto betaling =",W) + showEuro(monthlyPayment,WD) + " eur.\n") ;
		o.append(leftAlign("** Bijkomende koopkosten =",W) + showEuro(getOverheadCost(),WD) + " eur. (" +
                (toFloat(purchaseCostPercentage)/100f) + " %)\n"
                ) ;
		o.append(leftAlign("** Koopwaarde van uw huis =",W) + showEuro(getHousePurchaseValue(),WD) + " eur.\n") ;
		o.append(leftAlign("** Bruto jaarsalaris =",W) + showEuro(income,WD) + " eur.\n") ;
        o.append(leftAlign("   Eigenwoningforfait =",W) + showEuro(getEigenWoningforfait(),WD) + " eur.\n") ;
		
		o.append("\nBEREKENING OVERZICHT:\n") ;
		
		if (R == null) {
			
			int interest = calcMonthlyInterest(loan) ;
			int minMpay = interest/100 + lifeInsurancePremium ;
			o.append("   Uw voorstel is niet realiseerbaar.\n") ;
			o.append("   Leen minder, of zet maandelijksbetaling op minstens "
					+ minMpay + " eur.\n") ;
			return o.toString() ;
		}
		
		int actualDuration = R.loanPayBacks.size() ;
		
		if (actualDuration < duration)
			o.append(leftAlign("** Werkelijke leenperiode =",W) 
					+ rightAlign("" + actualDuration,WD-3) + " maanden ("
					+ month2year(actualDuration) + " jaar)\n") ;
		
		o.append(leftAlign("** Overgeblevende lening  =",W) 
				+ showEuro(R.remaining - R.totSaved,WD) + " eur.\n") ;
		
		o.append(leftAlign("** Totaal afgelost =",W) 
				+ showEuro(loan - R.remaining,WD) + " eur.\n") ;

        if (percentageToSave>0) {
            //System.out.println(">>>" + R.totSaved) ;
            o.append(leftAlign("** Totaal gespaard =",W)
				+ showEuro(R.totSaved,WD) + " eur.\n") ;
        }

		o.append(leftAlign("** Totaal kwijt aan rente =",W) 
				+ showEuro(R.totInterest,WD) + " eur.\n") ;
		
		o.append(leftAlign("** Totaal bruto betaald   =",W) 
				+ showEuro(R.totPaidBruto,WD) + " eur.\n") ;
		
		o.append(leftAlign("** Totaal netto betaald   =",W) 
				+ showEuro(R.totPaidNetto,WD) + " eur.\n") ;
		
		o.append(leftAlign("** Totaal belst. aftrek =",W) 
				+ showEuro(R.totTaxReduction,WD) + " eur.\n") ;
		
		double priceGrowthPercetage = round(toDouble(assumedHousePriceIncrRate)/100d ,2) ;
		
		o.append(leftAlign("** Eindwaarde huis =",W) 
				+ showEuro(R.projectedHouseValue,WD) + " eur."
				+ " (op basis van " + priceGrowthPercetage + " % prijsgroei)\n" ) ;
		
		o.append(leftAlign("** Uw resultaat =",W)
				+ showEuro(R.profit,WD) + " eur.\n" ) ;
		
		return o.toString() ;
	}

	public String printYearReport(Result R, int year) {
		int start = 12 * (year - 1) ;
		int N = R.interestPayments.size() ;
		assert start < N : "PRE" ;
		int end = Math.min(start+12, N) ;
		
		int totInterest = 0 ;
		int totLoanPaidBack = 0 ;
        
		int totBrutoPaid = 0 ;
		int totTaxReduction = 0 ;
		int totNettoPaid = 0 ;
		int remaining = loan ;
        int paidForSaving = 0 ;
		
		for (int k=start; k<end; k++) {
			totInterest += R.interestPayments.get(k) ;
			totBrutoPaid += R.interestPayments.get(k) + R.loanPayBacks.get(k) + R.saved.get(k);
            totLoanPaidBack += R.loanPayBacks.get(k) ;
  			totTaxReduction += R.taxReductions.get(k) ;
            paidForSaving += R.saved.get(k) ;
        }
		totNettoPaid = totBrutoPaid - totTaxReduction ;
		int totSaved = R.progressTotalSaved.get(end-1) ;


		for (int i=0; i<end; i++) remaining = remaining - R.loanPayBacks.get(i) ;
		
		StringBuffer o = new StringBuffer() ;
        int W = 31 ;
        int WD = 12 ;
		
        o.append("OVERZICHT JAAR " + year + ":\n") ;
        
		o.append(leftAlign("** Betaald voor aflossing =",W)
				+ showEuro(totLoanPaidBack,WD) + " eur.\n") ;

        if (percentageToSave>0) {
            o.append(leftAlign("** Betaald voor sparen =",W)
                    + showEuro(paidForSaving,WD) + " eur.\n") ;
         }

		o.append(leftAlign("** Betaald aan rente =",W)
				+ showEuro(totInterest,WD) + " eur.\n") ;

        if (lifeInsurancePremium>0)
            o.append(leftAlign("** Levensverz. premie =",W)
				+ showEuro(lifeInsurancePremium*(end-start),WD) + " eur.\n") ;

		o.append(leftAlign("** Totaal bruto betaald   =",W)
				+ showEuro(totBrutoPaid,WD) + " eur.\n") ;
		
		o.append(leftAlign("** Totaal netto betaald   =",W)
				+ showEuro(totNettoPaid,WD) + " eur.\n") ;
		
		o.append(leftAlign("** Belasting aftrek =",W)
				+ showEuro(totTaxReduction,WD) + " eur.\n") ;

		o.append(leftAlign("** Overgeblevende lening  =",W) 
				+ showEuro(remaining,WD) + " eur.\n") ;

        if (percentageToSave>0) {
                o.append(leftAlign("** Tot nu toe gespaard =",W)
				+ showEuro(totSaved,WD) + " eur.\n") ;
         }

		
		o.append("\nMAANDELIJKSBETALINGEN :\n") ;
		
		int W2 = 30 ;
		
		for (int k=start; k<end; k++) {
			o.append("   Maand " + (k+1) + "\n") ;
			o.append(leftAlign("      Rente =",W2) 
					+ showEuro(R.interestPayments.get(k),WD) + " eur.\n") ;
			o.append(leftAlign("      Aflossing =",W2) 
					+ showEuro(R.loanPayBacks.get(k),WD) + " eur.\n") ;
            if (lifeInsurancePremium>0)
                o.append(leftAlign("      Levensverz. premie =",W2)
				+ showEuro(lifeInsurancePremium,WD) + " eur.\n") ;
            if (percentageToSave>0) {
                o.append(leftAlign("      Sparen =",W2)
				+ showEuro(R.saved.get(k),WD) + " eur.\n") ;
            }
			int brutoSum = R.interestPayments.get(k) + R.loanPayBacks.get(k) + R.saved.get(k);
			int nettoSum = brutoSum - R.taxReductions.get(k) ;
			o.append(leftAlign("      Bruto betaald =",W2) 
					+ showEuro(brutoSum,WD) + " eur.\n") ;
			o.append(leftAlign("      Netto betaald =",W2) 
					+ showEuro(nettoSum,WD) + " eur.\n") ;
			
		}

		return o.toString() ;
	}
	
	static public void main(String[] args) {
		
		Hypotheek H = new Hypotheek() ;
		H.setLoan(250000 * 100) ;
		H.setDuration(MAX_LOAN_DURATION) ;
		H.setIterest((int) (4.5f * 100f)) ;
		H.setIncome(40000 * 100) ;
		H.setMonthlyPayment(1150 * 100) ;
		Result R = H.calculate() ;
		System.out.println(H.printGenStatistics(R)) ;
		System.out.println(H.printYearReport(R,1)) ;
		System.out.println(H.printYearReport(R,30)) ;
		
	}
	
}