/*
 * Entagged Audio Tag library
 * Copyright (c) 2003-2005 Christian Laireiter <liree@web.de>
 * 
 * This library 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 (at your option) any later version.
 *  
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
package entagged.audioformats.mp3.util.id3frames;

import java.io.UnsupportedEncodingException;
import java.text.DecimalFormat;
import java.util.Calendar;

/**
 * This specialization of a text field represents ID3v2 timestamp fields since
 * 2.4.<br>
 * <b>Warning:</b> For now only the year will be processed. Other information
 * will be discarded.
 * <p>
 * The Time field allows various patterns:<br>
 * <ul>
 * <li>yyyy</li>
 * <li>yyyy-MM</li>
 * <li>yyyy-MM-dd</li>
 * <li>yyyy-MM-ddTHH</li>
 * <li>yyyy-MM-ddTHH:mm</li>
 * <li>yyyy-MM-ddTHH:mm:ss</li>
 * </ul>
 * </p>
 * 
 * @author Christian Laireiter
 */
public class TimeId3Frame extends TextId3Frame {

	/**
	 * This method creates the string representation for the time value given by
	 * the calendar.<br>
	 * <b>Warning:</b> For now only the year will be processed. Other
	 * information will be discarded.
	 * 
	 * @param calendar
	 *            the time to create a string of.
	 * @return A string storing the id3v2.4 timestamp.
	 */
	private static String createString(Calendar calendar) {
		StringBuffer result = new StringBuffer();
		result.append(new DecimalFormat("0000").format(calendar
				.get(Calendar.YEAR)));
		return result.toString();
	}

	/**
	 * Creates a timestamp field.
	 * 
	 * @param fieldId
	 *            frame identifier.
	 * @param rawContent
	 *            the raw data of the frame.
	 * @param version
	 *            the version identifier of the tag.
	 * @throws UnsupportedEncodingException
	 *             When encoding is not supported.
	 */
	public TimeId3Frame(String fieldId, byte[] rawContent, byte version)
			throws UnsupportedEncodingException {
		super(fieldId, rawContent, version);
	}

	/**
	 * Creates a timestamp field.
	 * 
	 * @param fieldId
	 *            frame identifier.
	 * @param calendar
	 *            Calendar containing the represented time.
	 */
	public TimeId3Frame(String fieldId, Calendar calendar) {
		super(fieldId, createString(calendar));
	}

	/**
	 * Creates a timestamp field.
	 * 
	 * @param fieldId
	 *            frame identifier.
	 * @param content
	 *            The content of the field in string representation.
	 */
	public TimeId3Frame(String fieldId, String content) {
		super(fieldId, content);
	}

	/**
	 * (overridden)
	 * 
	 * @see entagged.audioformats.mp3.util.id3frames.TextId3Frame#populate(byte[])
	 */
	protected void populate(byte[] raw) throws UnsupportedEncodingException {
		super.populate(raw);
		this.content = this.content.substring(0, 4);
	}

}