/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.ode.utils.xsd;

import java.math.BigDecimal;
import java.util.Calendar;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Support for xml schema duration.
 * 
 * Does NOT support negative duration, only positive!!
 */
public class Duration {
	static final Pattern PATTERN = 
			Pattern.compile("P(\\d+Y)?(\\d+M)?(\\d+D)?(T(\\d+H)?(\\d+M)?((\\d+\\.?\\d*|\\.\\d+)S)?)?");
	
	static final int YEAR_MG = 1;
	static final int MONTH_MG = 2;
	static final int DAY_MG = 3;
	static final int HOUR_MG = 5;
	static final int MIN_MG = 6;
	static final int SEC_MG = 8;
	
	private int _years;
	private int _months;
	private int _days;
	private int _hours;
	private int _minutes;
	private BigDecimal _seconds;
	
	/**
	 * 
	 */
	public Duration(String duration) {
		Matcher m = PATTERN.matcher(duration);
		if(m.matches()){
			_years = parseInt(m.group(YEAR_MG));
			_months = parseInt(m.group(MONTH_MG));
			_days = parseInt(m.group(DAY_MG));
			_hours = parseInt(m.group(HOUR_MG));
			_minutes = parseInt(m.group(MIN_MG));
			_seconds = m.group(SEC_MG) == null
				? null : new BigDecimal(m.group(SEC_MG));		
		}
		else{
			throw new IllegalArgumentException("Bad duration: " + duration);
		}
	}
	
	/**
	 * Adds current duration to a calendar object.
	 * @param calendar
	 */
	public void addTo(Calendar calendar){
	
		calendar.add( Calendar.YEAR, _years );
	  calendar.add( Calendar.MONTH, _months );
	  calendar.add( Calendar.DAY_OF_MONTH, _days );
	  calendar.add( Calendar.HOUR, _hours );
	  calendar.add( Calendar.MINUTE, _minutes );
	  calendar.add( Calendar.SECOND,  (_seconds == null)
	  		? 0 : _seconds.intValue());
	  
	  if(_seconds!=null) {
      BigDecimal fraction = _seconds.subtract(_seconds.setScale(0,BigDecimal.ROUND_DOWN));
      int millisec = fraction.movePointRight(3).intValue();
      calendar.add( Calendar.MILLISECOND, millisec );
	  }
	}
	
	private static int parseInt(String value){
		if(value == null)
			return 0;
		else{
			return Integer.parseInt(value.substring(0, value.length()-1));
		}
	}
}