static void exchangeCurrencyForNXT(
Transaction transaction,
Account account,
final long currencyId,
final long rateNQT,
long units) {
long extraAmountNQT = 0;
long remainingUnits = units;
List<CurrencyBuyOffer> currencyBuyOffers = new ArrayList<>();
try (DbIterator<CurrencyBuyOffer> offers =
CurrencyBuyOffer.getOffers(
new ValidOffersDbClause(currencyId, rateNQT, true),
0,
-1,
" ORDER BY rate DESC, creation_height ASC, transaction_height ASC, transaction_index ASC ")) {
for (CurrencyBuyOffer offer : offers) {
currencyBuyOffers.add(offer);
}
}
for (CurrencyBuyOffer offer : currencyBuyOffers) {
if (remainingUnits == 0) {
break;
}
long curUnits = Math.min(Math.min(remainingUnits, offer.getSupply()), offer.getLimit());
long curAmountNQT = Math.multiplyExact(curUnits, offer.getRateNQT());
extraAmountNQT = Math.addExact(extraAmountNQT, curAmountNQT);
remainingUnits = Math.subtractExact(remainingUnits, curUnits);
offer.decreaseLimitAndSupply(curUnits);
long excess = offer.getCounterOffer().increaseSupply(curUnits);
Account counterAccount = Account.getAccount(offer.getAccountId());
counterAccount.addToBalanceNQT(-curAmountNQT);
counterAccount.addToCurrencyUnits(currencyId, curUnits);
counterAccount.addToUnconfirmedCurrencyUnits(currencyId, excess);
Exchange.addExchange(
transaction, currencyId, offer, account.getId(), offer.getAccountId(), curUnits);
}
account.addToBalanceAndUnconfirmedBalanceNQT(extraAmountNQT);
account.addToCurrencyUnits(currencyId, -(units - remainingUnits));
account.addToUnconfirmedCurrencyUnits(currencyId, remainingUnits);
}
