/**
 * <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.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 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
    
    // BKU writes a Z after the date for some reason.
    Pattern date_pattern = Pattern.compile("^\\d\\d\\d\\d-\\d\\d-\\d\\dT\\d\\d:\\d\\d:\\d\\d[Z]?$");
    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);
  }

  /**
   * @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;
  }

}