/**
* Compares the given monies.
*
* The amount is not rounded before comparison, so the results are more relevant than when using
* `convert($a, $b->getCurrency())->compareTo($b)`.
*
* Note that the comparison is performed by converting A into B's currency.
* This order is important if the exchange rate provider uses different exchange rates
* when converting back and forth two currencies.
*
* @param Money $a
* @param Money $b
*
* @return int -1, 0 or 1.
*
* @throws CurrencyConversionException If the exchange rate is not available.
*/
public function compare(Money $a, Money $b)
{
$aCurrencyCode = $a->getCurrency()->getCode();
$bCurrencyCode = $b->getCurrency()->getCode();
if ($aCurrencyCode === $bCurrencyCode) {
return $a->compareTo($b);
}
$aAmount = $a->getAmount();
$bAmount = $b->getAmount();
$exchangeRate = $this->exchangeRateProvider->getExchangeRate($aCurrencyCode, $bCurrencyCode);
$aAmount = $aAmount->toBigRational()->multipliedBy($exchangeRate);
return $aAmount->compareTo($bAmount);
}