package org.jquantlib.pricingengines.bond;

import org.jquantlib.QL;
import org.jquantlib.cashflow.CashFlows;
import org.jquantlib.cashflow.Leg;
import org.jquantlib.instruments.Bond;
import org.jquantlib.quotes.Handle;
import org.jquantlib.termstructures.AbstractYieldTermStructure;
import org.jquantlib.termstructures.YieldTermStructure;
import org.jquantlib.time.Date;

public class DiscountingBondEngine extends Bond.EngineImpl {

	private final Handle discountCurve;

	public DiscountingBondEngine() {

	    // this(new Handle(YieldTermStructure.class)); //FIXME::RG::Handle

        this(new Handle(
                new AbstractYieldTermStructure() {
                    @Override
                    protected double discountImpl(final double t) {
                        throw new UnsupportedOperationException();
                    }
                    @Override
                    public Date maxDate() {
                        throw new UnsupportedOperationException();
                    }
                }
        ));

	}

    public DiscountingBondEngine(final Handle  discountCurve) {
        this.discountCurve = discountCurve;
        this.discountCurve.addObserver(this);
    }

    @Override
    public void calculate() /* @ReadOnly */ {
        //TODO: study performance .vs. defensive programming
        // QL.require(Bond.Arguments.class.isAssignableFrom(arguments.getClass()), ReflectConstants.WRONG_ARGUMENT_TYPE); // QA:[RG]::verified
        // QL.require(Bond.Results.class.isAssignableFrom(results.getClass()), ReflectConstants.WRONG_ARGUMENT_TYPE); // QA:[RG]::verified

        final Bond.ArgumentsImpl a = (Bond.ArgumentsImpl)arguments_;
        final Bond.ResultsImpl   r = (Bond.ResultsImpl)results_;

    	final Leg cashflows = a.cashflows;
    	final Date settlementDate = a.settlementDate;
    	final Date valuationDate = discountCurve.currentLink().referenceDate();
        QL.require(! discountCurve.empty() , "no discounting term structure set"); //// TODO: message

        r.value           = CashFlows.getInstance().npv(cashflows, discountCurve, valuationDate,  valuationDate);
        r.settlementValue = CashFlows.getInstance().npv(cashflows, discountCurve, settlementDate, settlementDate);
    }


    public Handle discountCurve() /* @ReadOnly */ {
    	return discountCurve;
    }

}