/*
 *
 *    OPEN-XCHANGE legal information
 *
 *    All intellectual property rights in the Software are protected by
 *    international copyright laws.
 *
 *
 *    In some countries OX, OX Open-Xchange, open xchange and OXtender
 *    as well as the corresponding Logos OX Open-Xchange and OX are registered
 *    trademarks of the Open-Xchange, Inc. group of companies.
 *    The use of the Logos is not covered by the GNU General Public License.
 *    Instead, you are allowed to use these Logos according to the terms and
 *    conditions of the Creative Commons License, Version 2.5, Attribution,
 *    Non-commercial, ShareAlike, and the interpretation of the term
 *    Non-commercial applicable to the aforementioned license is published
 *    on the web site http://www.open-xchange.com/EN/legal/index.html.
 *
 *    Please make sure that third-party modules and libraries are used
 *    according to their respective licenses.
 *
 *    Any modifications to this package must retain all copyright notices
 *    of the original copyright holder(s) for the original code used.
 *
 *    After any such modifications, the original and derivative code shall remain
 *    under the copyright of the copyright holder(s) and/or original author(s)per
 *    the Attribution and Assignment Agreement that can be located at
 *    http://www.open-xchange.com/EN/developer/. The contributing author shall be
 *    given Attribution for the derivative code and a license granting use.
 *
 *     Copyright (C) 2004-2011 Open-Xchange, Inc.
 *     Mail: info@open-xchange.com
 *
 *
 *     This program is free software; you can redistribute it and/or modify it
 *     under the terms of the GNU General Public License, Version 2 as published
 *     by the Free Software Foundation.
 *
 *     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
 *
 */

package com.openexchange.tools.versit.valuedefinitions.rfc2425;

import java.io.IOException;
import java.text.DecimalFormat;
import java.util.Calendar;
import java.util.regex.Pattern;
import com.openexchange.tools.TimeZoneUtils;
import com.openexchange.tools.versit.Property;
import com.openexchange.tools.versit.StringScanner;
import com.openexchange.tools.versit.ValueDefinition;
import com.openexchange.tools.versit.VersitException;
import com.openexchange.tools.versit.values.DateTimeValue;

/**
 * @author Viktor Pracht
 */
public class DateTimeValueDefinition extends ValueDefinition {

    public static final ValueDefinition Default = new DateTimeValueDefinition();

    private static Pattern TZPattern = Pattern.compile("[-+]\\d{2}:?\\d{2}");

    @Override
    public Object createValue(final StringScanner s, final Property property) throws IOException {
        final DateTimeValue date = new DateTimeValue();
        parseDate(s, date);
        if (s.peek != 'T') {
            throw new VersitException(s, "Date and time expected");
        }
        s.read();
        parseTime(s, date);
        return date;
    }

    protected void parseDate(final StringScanner s, final DateTimeValue date) throws IOException {
        date.calendar.set(Calendar.YEAR, s.parseNumber(4));
        if (s.peek == '-') {
            s.read();
        }
        date.calendar.set(Calendar.MONTH, s.parseNumber(2) - 1);
        if (s.peek == '-') {
            s.read();
        }
        date.calendar.set(Calendar.DATE, s.parseNumber(2));
    }

    protected void parseTime(final StringScanner s, final DateTimeValue date) throws IOException {
        date.calendar.set(Calendar.HOUR_OF_DAY, s.parseNumber(2));
        skipColon(s);
        date.calendar.set(Calendar.MINUTE, s.parseNumber(2));
        skipColon(s);
        date.calendar.set(Calendar.SECOND, s.parseNumber(2));
        if (s.peek == '.') {
            s.read();
            int ms = 0;
            for (int scale = 100; s.peek >= '0' && s.peek <= '9' && scale >= 1; scale /= 10) {
                ms += scale * (s.read() - '0');
            }
            date.calendar.set(Calendar.MILLISECOND, ms);
            while (s.peek >= '0' && s.peek <= '9') {
                s.read();
            }
        }
        final StringBuilder tz = new StringBuilder("GMT");
        if (s.peek == 'Z') {
            s.read();
        } else {
            final String offs = s.regex(TZPattern);
            if (offs == null) {
                date.isFloating = true;
            } else {
                tz.append(offs);
                date.isUTC = false;
            }
        }
        date.calendar.setTimeZone(TimeZoneUtils.getTimeZone(tz.toString()));
    }

    private void skipColon(final StringScanner s) throws IOException {
        if (s.peek == '\\') {
            s.read();
        }
        if (s.peek == ':') {
            s.read();
        }
    }

    @Override
    public String writeValue(final Object value) {
        final DateTimeValue dtval = (DateTimeValue) value;
        final StringBuilder sb = new StringBuilder();
        if (dtval.hasDate) {
            sb.append(writeDate(dtval));
        }
        if (dtval.hasTime) {
            sb.append('T');
            sb.append(writeTime(dtval));
        }
        return sb.toString();
    }

    private static final DecimalFormat YearFormat = new DecimalFormat("0000");

    private static final DecimalFormat Format = new DecimalFormat("00");

    private static final DecimalFormat MSFormat = new DecimalFormat("000");

    protected String writeDate(final DateTimeValue dtval) {
        return YearFormat.format(dtval.calendar.get(Calendar.YEAR)) + Format.format(dtval.calendar.get(Calendar.MONTH) + 1) + Format.format(dtval.calendar.get(Calendar.DATE));
    }

    protected String writeTime(final DateTimeValue dtval) {
        final StringBuilder sb = new StringBuilder();
        sb.append(Format.format(dtval.calendar.get(Calendar.HOUR_OF_DAY)));
        sb.append(Format.format(dtval.calendar.get(Calendar.MINUTE)));
        sb.append(Format.format(dtval.calendar.get(Calendar.SECOND)));
        final int ms = dtval.calendar.get(Calendar.MILLISECOND);
        if (ms != 0) {
            sb.append('.');
            sb.append(MSFormat.format(ms));
        }
        if (!dtval.isFloating) {
            final int offset = dtval.calendar.getTimeZone().getRawOffset();
            if (dtval.isUTC || offset == 0) {
                sb.append('Z');
            } else {
                sb.append(offset > 0 ? '+' : '-');
                sb.append(Format.format(offset / 3600000));
                sb.append(Format.format(offset / 60000 % 60));
            }
        }
        return sb.toString();
    }

}
