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 * Copyright © 2013-2016 The Nxt Core Developers.                             *
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 * See the AUTHORS.txt, DEVELOPER-AGREEMENT.txt and LICENSE.txt files at      *
 * the top-level directory of this distribution for the individual copyright  *
 * holder information and the developer policies on copyright and licensing.  *
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 * Unless otherwise agreed in a custom licensing agreement, no part of the    *
 * Nxt software, including this file, may be copied, modified, propagated,    *
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 ******************************************************************************/

package nxt.http;

import nxt.Account;
import nxt.Attachment;
import nxt.Currency;
import nxt.NxtException;
import org.json.simple.JSONStreamAware;

import javax.servlet.http.HttpServletRequest;

/**
 * Generate new currency units
 * <p>
 * Parameters
 * <ul>
 * <li>currency - currency id of the minted currency</li>
 * <li>nonce - a unique nonce provided by the miner</li>
 * <li>units - number of units minted per this transaction</li>
 * <li>counter - a sequential number counting the ordinal mint operation number per currency/account combination<br>
 * this ever increasing value ensures that the same mint transaction cannot execute more than once</li>
 * </ul>
 *
 * Each minting request triggers a hash calculation based on the submitted data and the currency hash algorithm<br>
 * The resulting hash code is compared to the target value derived from the current difficulty.<br>
 * If the hash code is smaller than the target the currency units are generated into the sender account.<br>
 * It is recommended to calculate the hash value offline before submitting the transaction.<br>
 * Use the {@link GetMintingTarget} transaction to retrieve the current hash target and then calculate the hash offline
 * by following the procedure used in {@link nxt.CurrencyMint#mintCurrency}<br>
 */
public final class CurrencyMint extends CreateTransaction {

    static final CurrencyMint instance = new CurrencyMint();

    private CurrencyMint() {
        super(new APITag[] {APITag.MS, APITag.CREATE_TRANSACTION}, "currency", "nonce", "units", "counter");
    }

    @Override
    JSONStreamAware processRequest(HttpServletRequest req) throws NxtException {
        Currency currency = ParameterParser.getCurrency(req);
        long nonce = ParameterParser.getLong(req, "nonce", Long.MIN_VALUE, Long.MAX_VALUE, true);
        long units = ParameterParser.getLong(req, "units", 0, Long.MAX_VALUE, true);
        long counter = ParameterParser.getLong(req, "counter", 0, Integer.MAX_VALUE, true);
        Account account = ParameterParser.getSenderAccount(req);

        Attachment attachment = new Attachment.MonetarySystemCurrencyMinting(nonce, currency.getId(), units, counter);
        return createTransaction(req, account, attachment);
    }

}