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) ;

 	}		

 }