/******************************************************************************
 * 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.  *
 *                                                                            *
 * Unless otherwise agreed in a custom licensing agreement, no part of the    *
 * Nxt software, including this file, may be copied, modified, propagated,    *
 * or distributed except according to the terms contained in the LICENSE.txt  *
 * file.                                                                      *
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 * Removal or modification of this copyright notice is prohibited.            *
 *                                                                            *
 ******************************************************************************/

package nxt.http;

import nxt.Account;
import nxt.Attachment;
import nxt.Constants;
import nxt.DigitalGoodsStore;
import nxt.NxtException;
import nxt.util.Convert;
import org.json.simple.JSONStreamAware;

import javax.servlet.http.HttpServletRequest;

import static nxt.http.JSONResponses.INCORRECT_DELTA_QUANTITY;
import static nxt.http.JSONResponses.MISSING_DELTA_QUANTITY;
import static nxt.http.JSONResponses.UNKNOWN_GOODS;

public final class DGSQuantityChange extends CreateTransaction {

    static final DGSQuantityChange instance = new DGSQuantityChange();

    private DGSQuantityChange() {
        super(new APITag[] {APITag.DGS, APITag.CREATE_TRANSACTION},
                "goods", "deltaQuantity");
    }

    @Override
    JSONStreamAware processRequest(HttpServletRequest req) throws NxtException {

        Account account = ParameterParser.getSenderAccount(req);
        DigitalGoodsStore.Goods goods = ParameterParser.getGoods(req);
        if (goods.isDelisted() || goods.getSellerId() != account.getId()) {
            return UNKNOWN_GOODS;
        }

        int deltaQuantity;
        try {
            String deltaQuantityString = Convert.emptyToNull(req.getParameter("deltaQuantity"));
            if (deltaQuantityString == null) {
                return MISSING_DELTA_QUANTITY;
            }
            deltaQuantity = Integer.parseInt(deltaQuantityString);
            if (deltaQuantity > Constants.MAX_DGS_LISTING_QUANTITY || deltaQuantity < -Constants.MAX_DGS_LISTING_QUANTITY) {
                return INCORRECT_DELTA_QUANTITY;
            }
        } catch (NumberFormatException e) {
            return INCORRECT_DELTA_QUANTITY;
        }

        Attachment attachment = new Attachment.DigitalGoodsQuantityChange(goods.getId(), deltaQuantity);
        return createTransaction(req, account, attachment);

    }

}