/**
 * The MIT License
 *
 * Copyright (c) 2010-2011 Sonatype, Inc. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package org.hudsonci.utils.common;

import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Helper for working with dates.
 *
 * @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
 * @since 2.1.0
 */
public class Dates
{
    private static final int MILLISECONDS_IN_DAY = 1000 * 60 * 60 * 24;

    public static long countDaysBetween(final Date start, final Date end) {
        checkNotNull(start);
        checkNotNull(end);

        //reset all hours mins and secs to zero on start date
        Calendar startCal = GregorianCalendar.getInstance();
        startCal.setTime(start);
        startCal.set(Calendar.HOUR_OF_DAY, 0);
        startCal.set(Calendar.MINUTE, 0);
        startCal.set(Calendar.SECOND, 0);
        long startTime = startCal.getTimeInMillis();

        //reset all hours mins and secs to zero on end date
        Calendar endCal = GregorianCalendar.getInstance();
        endCal.setTime(end);
        endCal.set(Calendar.HOUR_OF_DAY, 0);
        endCal.set(Calendar.MINUTE, 0);
        endCal.set(Calendar.SECOND, 0);
        long endTime = endCal.getTimeInMillis();

        return (endTime - startTime) / MILLISECONDS_IN_DAY;
    }
}