/*************************************************************************
 *                                                                       *
 *  CERT-CVC: EAC 1.11 Card Verifiable Certificate Library               * 
 *                                                                       *
 *  This software 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 2.1 of the License, or any later version.                    *
 *                                                                       *
 *  See terms of license at gnu.org.                                     *
 *                                                                       *
 *************************************************************************/
package org.ejbca.cvc;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

/**
 * Represents a CVC field of type Date
 * 
 * @author Keijo Kurkinen, Swedish National Police Board
 * @version $Id: DateField.java 23378 2016-05-09 12:55:41Z netmackan $
 * 
 */
public class DateField extends AbstractDataField {

    private static final long serialVersionUID = 6092901788235446614L;

    /** The length of the array is always the same */
    private static final int DATE_ARRAY_SIZE = 6;

    /** Time Zone GMT must be used for effective and expiration dates */
    private static final TimeZone GMTTIMEZONE = TimeZone.getTimeZone("GMT");

    /** Date format when returning this object as text */
    private static final DateFormat FORMAT_PRINTABLE = new SimpleDateFormat("yyyy-MM-dd");
    static {
	FORMAT_PRINTABLE.setTimeZone(GMTTIMEZONE);
    }

    private Date date;

    DateField(CVCTagEnum type) {
	super(type);
    }

    /**
     * Constructs a new instance from tag and Date
     * 
     * @param type
     * @param date
     */
    DateField(CVCTagEnum type, Date date) {
	this(type);

	Calendar cal = Calendar.getInstance(GMTTIMEZONE);
	cal.setTimeInMillis(date.getTime());

	// Remove time part
	int year = cal.get(Calendar.YEAR);
	int month = cal.get(Calendar.MONTH);
	int day = cal.get(Calendar.DAY_OF_MONTH);
	cal.clear();
	cal.set(year, month, day);
	this.date = cal.getTime();
    }

    /**
     * Constructs instance by decoding DER-encoded data
     * 
     * @param type
     * @param data
     */
    DateField(CVCTagEnum type, byte[] data) {
	this(type);
	if (data == null || data.length != 6) {
	    throw new IllegalArgumentException(
		    "data argument must have length 6, was " + (data == null ? 0 : data.length));
	}
	int year = 2000 + data[0] * 10 + data[1];
	int month = data[2] * 10 + data[3] - 1; // Java month index starts with
						// 0...
	int day = data[4] * 10 + data[5];
	// Now create a Date instance using the decoded values
	Calendar cal = Calendar.getInstance(GMTTIMEZONE);
	cal.clear();
	if (type == CVCTagEnum.EFFECTIVE_DATE) {
	    cal.set(year, month, day, 0, 0, 0);
	} else { // EXPIRE_DATE
	    // Validity is inclusive this date, so to make sure that
	    // a Date comparison gives the expected result we add a
	    // time component
	    cal.set(year, month, day, 23, 59, 59);
	}
	date = cal.getTime();
    }

    /**
     * Returns the date
     * 
     * @return
     */
    public Date getDate() {
	return date;
    }

    /**
     * Encodes the date value so that every number in '080407' is stored as an
     * individual byte
     *
     * @return
     */
    @Override
    protected byte[] getEncoded() {
	byte[] dateArr = new byte[DATE_ARRAY_SIZE];

	Calendar cal = Calendar.getInstance(GMTTIMEZONE);
	cal.setTimeInMillis(date.getTime());
	int year = cal.get(Calendar.YEAR) - 2000; // Year is encoded as 08, 09,
						  // 10 ...
	int month = cal.get(Calendar.MONTH) + 1; // Month is encoded as 1,2, ...
						 // ,12
	int day = cal.get(Calendar.DAY_OF_MONTH);
	dateArr[0] = (byte) (year / 10);
	dateArr[1] = (byte) (year % 10);
	dateArr[2] = (byte) (month / 10);
	dateArr[3] = (byte) (month % 10);
	dateArr[4] = (byte) (day / 10);
	dateArr[5] = (byte) (day % 10);
	return dateArr;
    }

    @Override
    protected String valueAsText() {
	return FORMAT_PRINTABLE.format(date);
    }

}