/*
 * Duration.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU JAXP, a library.
 *
 * GNU JAXP 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
 * (at your option) any later version.
 * 
 * GNU JAXP 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
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version. 
 */

package javax.xml.datatype;

import java.math.BigDecimal;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import javax.xml.datatype.DatatypeConstants;
import javax.xml.namespace.QName;

/**
 * An immutable time space as specified in XML Schema 1.0.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 * @since 1.3
 */
public abstract class Duration
{

  /**
   * Returns the name of the XML Schema data type this value maps to.
   */
  public QName getXMLSchemaType()
  {
    int state = 0;
    state |= isSet(DatatypeConstants.YEARS) ? 32 : 0;
    state |= isSet(DatatypeConstants.MONTHS) ? 16 : 0;
    state |= isSet(DatatypeConstants.DAYS) ? 8 : 0;
    state |= isSet(DatatypeConstants.HOURS) ? 4 : 0;
    state |= isSet(DatatypeConstants.MINUTES) ? 2 : 0;
    state |= isSet(DatatypeConstants.SECONDS) ? 1 : 0;
    switch (state)
      {
      case 63:
        return DatatypeConstants.DURATION;
      case 15:
        return DatatypeConstants.DURATION_DAYTIME;
      case 48:
        return DatatypeConstants.DURATION_YEARMONTH;
      default:
        throw new IllegalStateException();
      }
  }

  /**
   * Returns the sign of this value.
   */
  public abstract int getSign();

  /**
   * Returns the years in this duration as an int, or 0 if not present.
   */
  public int getYears()
  {
    Number val = getField(DatatypeConstants.YEARS);
    return (val == null) ? 0 : val.intValue();
  }
  
  /**
   * Returns the months in this duration as an int, or 0 if not present.
   */
  public int getMonths()
  {
    Number val = getField(DatatypeConstants.MONTHS);
    return (val == null) ? 0 : val.intValue();
  }
  
  /**
   * Returns the days in this duration as an int, or 0 if not present.
   */
  public int getDays()
  {
    Number val = getField(DatatypeConstants.DAYS);
    return (val == null) ? 0 : val.intValue();
  }
  
  /**
   * Returns the hours in this duration as an int, or 0 if not present.
   */
  public int getHours()
  {
    Number val = getField(DatatypeConstants.HOURS);
    return (val == null) ? 0 : val.intValue();
  }
  
  /**
   * Returns the minutes in this duration as an int, or 0 if not present.
   */
  public int getMinutes()
  {
    Number val = getField(DatatypeConstants.MINUTES);
    return (val == null) ? 0 : val.intValue();
  }
  
  /**
   * Returns the seconds in this duration as an int, or 0 if not present.
   */
  public int getSeconds()
  {
    Number val = getField(DatatypeConstants.SECONDS);
    return (val == null) ? 0 : val.intValue();
  }

  /**
   * Returns the duration length in milliseconds.
   * Because the length of a month or year may vary depending on the year,
   * the <code>startInstant</code> parameter is used to specify the duration
   * offset.
   */
  public long getTimeInMillis(Calendar startInstant)
  {
    Calendar cal = (Calendar) startInstant.clone();
    long t1 = cal.getTimeInMillis();
    addTo(cal);
    long t2 = cal.getTimeInMillis();
    return t2 - t1;
  }

  /**
   * Returns the duration length in milliseconds.
   * Because the length of a month or year may vary depending on the year,
   * the <code>startInstant</code> parameter is used to specify the duration
   * offset.
   */
  public long getTimeInMillis(Date startInstant)
  {
    Date date = (Date) startInstant.clone();
    long t1 = date.getTime();
    addTo(date);
    long t2 = date.getTime();
    return t2 - t1;
  }

  /**
   * Returns the value of the specified field, or <code>null</code> if the
   * field is undefined.
   */
  public abstract Number getField(DatatypeConstants.Field field);

  /**
   * Indicates whether the specified field is set.
   */
  public abstract boolean isSet(DatatypeConstants.Field field);

  /**
   * Returns the result of adding the specified duration to this duration.
   */
  public abstract Duration add(Duration rhs);

  /**
   * Adds this duration to the specified calendar.
   */
  public abstract void addTo(Calendar calendar);
  /*{
    switch (getSign())
      {
      case -1:
        calendar.add(Calendar.YEAR, -getYears());
        calendar.add(Calendar.MONTH, -getMonths());
        calendar.add(Calendar.DATE, -getDays());
        calendar.add(Calendar.HOUR, -getHours());
        calendar.add(Calendar.MINUTE, -getMinutes());
        calendar.add(Calendar.SECOND, -getSeconds());
        break;
      case 1:
        calendar.add(Calendar.YEAR, getYears());
        calendar.add(Calendar.MONTH, getMonths());
        calendar.add(Calendar.DATE, getDays());
        calendar.add(Calendar.HOUR, getHours());
        calendar.add(Calendar.MINUTE, getMinutes());
        calendar.add(Calendar.SECOND, getSeconds());
      }
  }*/
  
  /**
   * Adds this duration to the specified date.
   */
  public void addTo(Date date)
  {
    Calendar calendar = new GregorianCalendar();
    calendar.setTimeInMillis(date.getTime());
    addTo(calendar);
    date.setTime(calendar.getTimeInMillis());
  }

  /**
   * Returns the result of subtracting the given duration from this
   * duration.
   */
  public Duration subtract(Duration rhs)
  {
    // TODO
    throw new UnsupportedOperationException();
  }

  /**
   * Returns the result of multiplying this duration by the given factor.
   */
  public Duration multiply(int factor)
  {
    return multiply(BigDecimal.valueOf((long) factor));
  }

  /**
   * Returns the result of multiplying this duration by the given factor.
   */
  public Duration multiply(BigDecimal factor)
  {
    // TODO
    throw new UnsupportedOperationException();
  }

  /**
   * Returns the unary negative of this duration.
   */
  public abstract Duration negate();
  
  /**
   * Converts the years and months fields into the days field using a
   * specific time instant as the reference point.
   */
  public abstract Duration normalizeWith(Calendar startTimeInstant);

  /**
   * Partial order relation comparison with this duration, in accordance
   * with XML Schema 1.0 Part 2, Section 3.2.7.6.2.
   */
  public abstract int compare(Duration duration);

  public boolean isLongerThan(Duration duration)
  {
    // TODO
    throw new UnsupportedOperationException();
  }

  public boolean isShorterThan(Duration duration)
  {
    // TODO
    throw new UnsupportedOperationException();
  }

  public boolean equals(java.lang.Object duration)
  {
    // TODO
    throw new UnsupportedOperationException();
  }
  
  public abstract int hashCode();

  /**
   * Returns the lexical representation of this duration.
   */
  public String toString()
  {
    // TODO
    throw new UnsupportedOperationException();
  }
  
}
