/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-06 Wolfgang M. Meier
 *  wolfgang@exist-db.org
 *  http://exist.sourceforge.net
 *  
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *  
 *  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 Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *  
 *  $Id$
 */
package org.exist.xquery.value;

import java.util.GregorianCalendar;

import javax.xml.datatype.DatatypeConstants;
import javax.xml.datatype.XMLGregorianCalendar;
import javax.xml.namespace.QName;

import org.exist.xquery.XPathException;

/**
 * @author Wolfgang Meier (wolfgang@exist-db.org)
 * @author <a href="mailto:piotr@ideanest.com">Piotr Kaminski</a>
 */
public class TimeValue extends AbstractDateTimeValue {

	public TimeValue() throws XPathException {
		super(stripCalendar(TimeUtils.getInstance().newXMLGregorianCalendar(new GregorianCalendar())));
	}

	public TimeValue(XMLGregorianCalendar calendar) throws XPathException {
		super(stripCalendar((XMLGregorianCalendar) calendar.clone()));
	}

	public TimeValue(String timeValue) throws XPathException {
		super(timeValue);
		try {
			if (calendar.getXMLSchemaType() != DatatypeConstants.TIME) throw new IllegalStateException();
		} catch (IllegalStateException e) {
			throw new XPathException("xs:time instance must not have year, month or day fields set");
		}
	}

	private static XMLGregorianCalendar stripCalendar(XMLGregorianCalendar calendar) {
		calendar = (XMLGregorianCalendar) calendar.clone();
		calendar.setYear(DatatypeConstants.FIELD_UNDEFINED);
		calendar.setMonth(DatatypeConstants.FIELD_UNDEFINED);
		calendar.setDay(DatatypeConstants.FIELD_UNDEFINED);
		return calendar;
	}

	protected AbstractDateTimeValue createSameKind(XMLGregorianCalendar cal) throws XPathException {
		return new TimeValue(cal);
	}

	protected QName getXMLSchemaType() {
		return DatatypeConstants.TIME;
	}

	public int getType() {
		return Type.TIME;
	}

	public AtomicValue convertTo(int requiredType) throws XPathException {
		switch (requiredType) {
			case Type.TIME :
			case Type.ATOMIC :
			case Type.ITEM :
				return this;
//		case Type.DATE_TIME :
//			xs:time -> xs:dateTime conversion not defined in Funcs&Ops 17.1.5
			case Type.STRING :
				return new StringValue(getStringValue());
			case Type.UNTYPED_ATOMIC :
				return new UntypedAtomicValue(getStringValue());
			default :
				throw new XPathException(
					"Type error: cannot cast xs:time to "
						+ Type.getTypeName(requiredType));
		}
	}

	public ComputableValue minus(ComputableValue other) throws XPathException {
		switch(other.getType()) {
			case Type.TIME:
				return new DayTimeDurationValue(getTimeInMillis() - ((TimeValue) other).getTimeInMillis());
			case Type.DAY_TIME_DURATION:
				return ((DayTimeDurationValue) other).negate().plus(this);
			default:
				throw new XPathException(
						"Operand to minus should be of type xs:time or xdt:dayTimeDuration; got: "
							+ Type.getTypeName(other.getType()));
		}
	}

	public ComputableValue plus(ComputableValue other) throws XPathException {
		if (other.getType() == Type.DAY_TIME_DURATION) {
			return other.plus(this);
		}
		throw new XPathException(
			"Operand to plus should be of type xdt:dayTimeDuration; got: "
				+ Type.getTypeName(other.getType()));
	}

}