package org.apidesign.apifest08.currency;

import java.math.BigDecimal;

import java.math.RoundingMode;

import java.util.Currency;

import static org.apidesign.apifest08.currency.Assert.*;

/**

 * A bid representation. A did is defined as two currenncies and its value. 

 */

public final class Bid {

	private final Currency first;

	private final Currency second;

	private final BigDecimal bidValue; // a bid between the first currency and the second currency

	public static final BigDecimal one = new BigDecimal(1);		

	Bid(Currency first, Currency second, BigDecimal bid) {

		notNull(first, "first");

		notNull(second, "second");

		this.first = first;

		this.bidValue = bid;

		this.second = second;	

	}

	Bid(Currency first, Currency second) {

		notNull(first, "first");

		notNull(second, "second");

		this.first = first;

		this.second = second;

		this.bidValue = null;

	}

	BigDecimal getBidValue(Currency from, Currency to) {

		if((from != first || from != second) || (to != first || to != second)) {

			new IllegalArgumentException("This bid can be used only for: " + first + " " + second);

		}

		notNull(bidValue, "bidValue");

		BigDecimal retVal;

		if(first == from) {

			retVal = bidValue;

		} else {	

			//reverse bid		

			retVal = one.divide(bidValue, 10 ,RoundingMode.HALF_UP);

		}

		return retVal;

	}

	@Override

	public int hashCode() {

		final int prime = 31;

		int result = 1;

		result = prime * result + first.hashCode() +  second.hashCode();

		return result;

	}

	@Override

	public boolean equals(Object obj) {

		if (this == obj)

			return true;

		if (obj == null)

			return false;

		if (getClass() != obj.getClass())

			return false;

		Bid other = (Bid) obj;

		return (this.first == other.first || this.first == other.second) && (this.second == other.second || this.second == other.first) ;

	}		

}