/*
 * $Header: /cvsroot/mvnforum/myvietnam/src/net/myvietnam/mvncore/util/DateUtil.java,v 1.8 2004/06/01 13:25:40 skoehler Exp $
 * $Author: skoehler $
 * $Revision: 1.8 $
 * $Date: 2004/06/01 13:25:40 $
 *
 * ====================================================================
 *
 * Copyright (C) 2002-2004 by MyVietnam.net
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or any later version.
 *
 * All copyright notices regarding MyVietnam and MyVietnam CoreLib
 * MUST remain intact in the scripts and source code.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * Correspondence and Marketing Questions can be sent to:
 * info@MyVietnam.net
 *
 * @author: Minh Nguyen  minhnn@MyVietnam.net
 * @author: Mai  Nguyen  mai.nh@MyVietnam.net
 */
package net.myvietnam.mvncore.util;

import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 * @todo: add config option to this class
 */
public final class DateUtil {

    public static final int SECOND  = 1000;
    public static final int MINUTE  = SECOND * 60;
    public static final int HOUR    = MINUTE * 60;
    public static final int DAY     = HOUR * 24;
    public static final int WEEK    = DAY * 7;
    public static final int YEAR    = DAY * 365; // or 366 ???

    /**
     * This is the time difference between GMT time and Vietnamese time
     */
    public static final long GMT_VIETNAM_TIME_OFFSET = HOUR * 7;

    /**
     * This is the time difference between GMT time and SERVER time
     */
    private static long SERVER_TIME_OFFSET = HOUR * (new DateOptions()).serverHourOffset;

    private static DateFormat ddMMyyyyFormat = new SimpleDateFormat ("dd/MM/yyyy");
    private static DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.DEFAULT);
    private static DateFormat datetimeFormat = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT);

    /**
     * private constructor
     */
    private DateUtil() {// prevent instantiation
    }

    public static synchronized String getDateDDMMYYYY(Date date) {
        return ddMMyyyyFormat.format(date);
    }

    public static synchronized String formatDate(Date date) {
        return dateFormat.format(date);
    }

    public static synchronized String formatDateTime(Date date) {
        return datetimeFormat.format(date);
    }

    public static Timestamp getCurrentGMTTimestamp() {
        return new Timestamp(System.currentTimeMillis() - SERVER_TIME_OFFSET);
    }

    public static void updateCurrentGMTTimestamp(Timestamp timeToUpdate) {
        timeToUpdate.setTime(System.currentTimeMillis() - SERVER_TIME_OFFSET);
    }

    public static Date getVietnamDateFromGMTDate(Date date) {
        return new Date(date.getTime() + GMT_VIETNAM_TIME_OFFSET);
    }

    public static Date convertGMTDate(Date gmtDate, int hourOffset) {
        return new Date(gmtDate.getTime() + hourOffset*HOUR);
    }

    public static Timestamp convertGMTTimestamp(Timestamp gmtTimestamp, int hourOffset) {
        return new Timestamp(gmtTimestamp.getTime() + hourOffset*HOUR);
    }

    public static Timestamp getCurrentGMTTimestampExpiredYear(int offsetYear) {
        //return new Timestamp(System.currentTimeMillis() + offsetYear*(365*24*60*60*1000));
        Calendar now = Calendar.getInstance();
        now.add(Calendar.YEAR, offsetYear);
        return new Timestamp(now.getTime().getTime());
    }

    public static Timestamp getCurrentGMTTimestampExpiredMonth(int offsetMonth) {
        Calendar now = Calendar.getInstance();
        now.add(Calendar.MONTH,offsetMonth);
        return new Timestamp(now.getTime().getTime());
    }

}