/*
 *
 * Copyright (c) 2013 - 2017 Lijun Liao
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 *
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * THE AUTHOR LIJUN LIAO. LIJUN LIAO DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the XiPKI software without
 * disclosing the source code of your own applications.
 *
 * For more information, please contact Lijun Liao at this
 * address: lijun.liao@gmail.com
 */

package org.xipki.commons.common.util;

import java.math.BigInteger;
import java.util.Iterator;
import java.util.List;

/**
 * @author Lijun Liao
 * @since 2.1.0
 */

public class RangeBigIntegerIterator implements Iterator<BigInteger> {

    private final List<BigIntegerRange> ranges;

    private final int sizeRanges;

    private final boolean loop;

    private int currentIndex;

    private BigInteger currentNumber;

    public RangeBigIntegerIterator(List<BigIntegerRange> ranges, boolean loop) {
        this.ranges = ParamUtil.requireNonEmpty("ranges", ranges);
        this.sizeRanges = ranges.size();
        this.loop = loop;
        this.currentIndex = 0;
        this.currentNumber = ranges.get(0).getFrom();
    }

    @Override
    public synchronized boolean hasNext() {
        return currentNumber != null;
    }

    @Override
    public synchronized BigInteger next() {
        if (currentNumber == null) {
            return null;
        }

        BigInteger ret = currentNumber;

        BigInteger nextNumber = currentNumber.add(BigInteger.ONE);
        BigIntegerRange range = ranges.get(currentIndex);
        if (range.isInRange(nextNumber)) {
            this.currentNumber = nextNumber;
        } else {
            this.currentIndex++;
            if (loop && this.currentIndex >= sizeRanges) {
                this.currentIndex = 0;
            }

            this.currentNumber = (this.currentIndex < sizeRanges)
                    ? ranges.get(this.currentIndex).getFrom() : null;
        }

        return ret;
    }

}