/**
 * <copyright> Copyright (c) 2006 by Know-Center, Graz, Austria </copyright>
 * 
 * This software is the confidential and proprietary information of Know-Center,
 * Graz, Austria. You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Know-Center.
 * 
 * KNOW-CENTER MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
 * NON-INFRINGEMENT. KNOW-CENTER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
 * LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES.
 * 
 * $Id: EGIZDate.java,v 1.1 2006/10/31 08:08:33 wprinz Exp $
 */
package at.knowcenter.wag.egov.egiz.pdf;

import java.text.ParseException;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.lang.time.DateUtils;

/**
 * Represents a signature date and the signing time as can be found in the
 * SIG_DATE field.
 * 
 * <p>
 * This is used to compare date values of signatures.
 * </p>
 * 
 * @author wprinz
 */
public class EGIZDate {

	/**
	 * The year.
	 */
	protected int year;

	/**
	 * The month.
	 */
	protected int month;

	/**
	 * The day.
	 */
	protected int day;

	/**
	 * The hour.
	 */
	protected int hour;

	/**
	 * The minute.
	 */
	protected int minute;

	/**
	 * The second.
	 */
	protected int second;

	/**
	 * Constructor that fills the date with values.
	 * 
	 * @param year
	 *            The year.
	 * @param month
	 *            The month.
	 * @param day
	 *            The day.
	 * @param hour
	 *            The hour.
	 * @param minute
	 *            The minute.
	 * @param second
	 *            The second.
	 */
	public EGIZDate(int year, int month, int day, int hour, int minute,
			int second) {
		this.year = year;
		this.month = month;
		this.day = day;
		this.hour = hour;
		this.minute = minute;
		this.second = second;
	}

	/**
	 * Parses the date information from a given date value.
	 * 
	 * <p>
	 * Usually the date value is one extracted from the value of the SIG_DATE
	 * field.
	 * </p>
	 * 
	 * @param date_value
	 *            The date value String.
	 * @return Returns the parsed EGIZDate. An IllegalArgumentException is
	 *         thrown if the date String has an illegal format.
	 */
	public static EGIZDate parseFromString(String date_value) {
		// find the according RFC standard and cite it

		/*
		 * Pattern date_pattern =
		 * Pattern.compile("^\\d\\d\\d\\d-\\d\\d-\\d\\dT\\d\\d:\\d\\d:\\d\\d(Z|((\\+|\\-)\\d\\d:\\d\\d))?$");
		 * Matcher date_matcher = date_pattern.matcher(date_value); if
		 * (!date_matcher.matches()) { throw new IllegalArgumentException("The
		 * date_value (" + date_value + ") has an illegal format."); } // for
		 * some strange reasons capture groups don't work
		 * 
		 * int year = Integer.parseInt(date_value.substring(0, 4)); int month =
		 * Integer.parseInt(date_value.substring(5, 7)); int day =
		 * Integer.parseInt(date_value.substring(8, 10)); int hour =
		 * Integer.parseInt(date_value.substring(11, 13)); int minute =
		 * Integer.parseInt(date_value.substring(14, 16)); int second =
		 * Integer.parseInt(date_value.substring(17, 19)); return new
		 * EGIZDate(year, month, day, hour, minute, second);
		 */

		String[] parsePatterns = { "yyyy-MM-dd'T'HH:mm:ss",
				"yyyy-MM-dd'T'HH:mm:ssZ", "yyyy-MM-dd'T'HH:mm:ssZZ" };		
		if (date_value.length() > 19) {
			int li = date_value.lastIndexOf(":");
			if (li >= 19) {
				date_value = new StringBuffer(date_value).deleteCharAt(li).toString();
			}
			if (date_value.endsWith("Z")) {
				date_value = date_value.substring(0, date_value.length()-2) + "UTC";
			}
		} else  {			
			date_value += "UTC";
		}		
		
		Date date;		
		try {
			date = DateUtils.parseDate(date_value, parsePatterns);
		} catch (ParseException e) {
			throw new IllegalArgumentException("The date_value (" + date_value
					+ ") has an illegal format.");
		}
		Calendar calendar = new GregorianCalendar();
		calendar.setTime(date);

		return new EGIZDate(calendar.get(Calendar.YEAR), calendar
				.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH),
				calendar.get(Calendar.HOUR), calendar.get(Calendar.MINUTE),
				calendar.get(Calendar.SECOND));

	}

	/**
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	public boolean equals(Object obj) {
		if (!(obj instanceof EGIZDate)) {
			return false;
		}

		return toString().equals(obj.toString());
	}

	/**
	 * @see java.lang.Object#hashCode()
	 */
	public int hashCode() {
		return toString().hashCode();
	}

	/**
	 * @see java.lang.Object#toString()
	 */
	public String toString() {
		return "parsed date = " + year + "-" + month + "-" + day + "T" + hour
				+ ":" + minute + ":" + second;
	}

	/**
	 * Converts the date to a long integer.
	 * 
	 * <p>
	 * An earlier date is lower than a later date.
	 * </p>
	 * <p>
	 * E.g. a date in 1999 will get a smaller number than a date in 2006.
	 * </p>
	 * 
	 * @return Returns the compareable long.
	 */
	protected long toCompareableLong() {
		return +this.year * 12 * 31 * 24 * 60 * 60 + this.month * 31 * 24 * 60
				* 60 + this.day * 24 * 60 * 60 + this.hour * 60 * 60
				+ this.minute * 60 + this.second;
	}

	/**
	 * Compares this EGIZDate to another EXIZDate.
	 * 
	 * @param other
	 *            The other EGIZDate.
	 * @return Returns negative if this date is earlier (lower) than the other
	 *         date. Returns 0 if both dates are equal. Returns positive if this
	 *         date is later (higher) than the other date.
	 */
	public int compareTo(EGIZDate other) {
		long diff = toCompareableLong() - other.toCompareableLong();
		return (int) diff;
	}

}