/***
    *     Ambient - A music player for the Android platform
    Copyright (C) 2007 Martin Vysny
    
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    
   This program 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 General Public License for more details.
  
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package sk.baka.ambient.stream.shoutcast;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.text.ParseException;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.Iterator;
  import java.util.List;
  
  import org.xml.sax.Attributes;
  import org.xml.sax.SAXException;
  import org.xml.sax.helpers.DefaultHandler;
  
  import sk.baka.ambient.collection.TrackMetadataBean;
  import sk.baka.ambient.commons.IOUtils;
  import sk.baka.ambient.commons.MiscUtils;
  import sk.baka.ambient.playlist.Parsers;
  
  /***
   * Utility methods for SHOUTcast support.
   * 
   * @author Martin Vysny
   */
  public final class ShoutcastUtils {
  	private ShoutcastUtils() {
  		throw new Error();
  	}
  
  	/***
  	 * Parses a playlist and returns list of all radio URLs (the
  	 * <code>File?=...</code> lines; other lines are ignored).
  	 * 
  	 * @param in
  	 *            the playlist stream. the stream is always closed.
  	 * @return list of URLs
  	 * @throws IOException
  	 *             if i/o error occurs.
  	 * @throws ParseException
  	 *             if the playlist is not well formed.
  	 */
  	public static List<TrackMetadataBean> parsePlaylist(final InputStream in)
  			throws IOException, ParseException {
  		return Parsers.parsePls(in, null);
  	}
  
  	/***
  	 * The genres list XML location.
  	 */
  	public static final URL GENRES_LIST;
  	static {
  		try {
  			GENRES_LIST = new URL("http://www.shoutcast.com/sbin/newxml.phtml");
  		} catch (MalformedURLException e) {
  			throw new RuntimeException(e);
  		}
  	}
  
  	/***
  	 * Parses the SHOUTcast genre list XML. Reads the XML from the server.
  	 * 
  	 * @return list of genres
  	 * @throws IOException
  	 * @throws SAXException
  	 */
  	public static List<String> parseGenres() throws IOException, SAXException {
  		return parseGenres(GENRES_LIST.openStream());
  	}
  
  	/***
  	 * Parses the SHOUTcast genre list XML.
  	 * 
  	 * @param in
  	 *            the XML to read. the stream is always closed.
  	 * @return list of genres
  	 * @throws IOException
  	 * @throws SAXException
  	 */
 	public static List<String> parseGenres(final InputStream in)
 			throws IOException, SAXException {
 		try {
 			final List<String> result = new ArrayList<String>();
 			IOUtils.parseXML(in, new GenreHandler(result));
 			Collections.sort(result, String.CASE_INSENSITIVE_ORDER);
 			return result;
 		} finally {
 			MiscUtils.closeQuietly(in);
 		}
 	}
 
 	/***
 	 * Handles list of genres.
 	 * 
 	 * @author Martin Vysny
 	 */
 	private static class GenreHandler extends DefaultHandler {
 		/***
 		 * Store the genres here.
 		 */
 		private final List<String> result;
 
 		/***
 		 * Creates new handler instance.
 		 * 
 		 * @param result
 		 *            store the genres here.
 		 */
 		public GenreHandler(List<String> result) {
 			this.result = result;
 		}
 
 		@Override
 		public void startElement(String uri, String localName, String name,
 				Attributes attributes) {
 			if (Thread.currentThread().isInterrupted()) {
 				throw new RuntimeException("interrupted");
 			}
 			if (!localName.equals("genre")) {
 				return;
 			}
 			final String genre = attributes.getValue("name");
 			if (genre != null) {
 				result.add(genre);
 			}
 		}
 	}
 
 	/***
 	 * Parses the server-side XML radio list and returns parsed object
 	 * instances.
 	 * 
 	 * @param genre
 	 *            the genre
 	 * @return radio list.
 	 * @throws SAXException
 	 * @throws IOException
 	 *             if i/o error occurs.
 	 */
 	public static List<Radio> getRadioList(final String genre)
 			throws IOException, SAXException {
 		final URL xml = new URL(GENRES_LIST.toString() + "?genre=" + genre);
 		return getRadioList(xml.openStream());
 	}
 
 	/***
 	 * Parses the XML radio list and returns parsed object instances.
 	 * 
 	 * @param in
 	 *            the XML to parse
 	 * @return radio list. The list is sorted by the radio name and duplicate
 	 *         items are removed.
 	 * @throws SAXException
 	 * @throws IOException
 	 *             if i/o error occurs.
 	 */
 	public static List<Radio> getRadioList(final InputStream in)
 			throws IOException, SAXException {
 		try {
 			final List<Radio> result = new ArrayList<Radio>();
 			IOUtils.parseXML(in, new RadioListHandler(result));
 			sortByName(result);
 			removeDups(result);
 			return result;
 		} finally {
 			MiscUtils.closeQuietly(in);
 		}
 	}
 
 	/***
 	 * Sorts given radio list by name.
 	 * 
 	 * @param radioList
 	 *            the list to sort.
 	 */
 	public static void sortByName(final List<Radio> radioList) {
 		Collections.sort(radioList, new Comparator<Radio>() {
 			public int compare(Radio object1, Radio object2) {
 				return object1.name.compareToIgnoreCase(object2.name);
 			}
 		});
 	}
 
 	private static void removeDups(final List<Radio> list) {
 		String lastName = null;
 		for (final Iterator<Radio> i = list.iterator(); i.hasNext();) {
 			final Radio r = i.next();
 			if (MiscUtils.nullEquals(lastName, r.name)) {
 				i.remove();
 			} else {
 				lastName = r.name;
 			}
 		}
 	}
 
 	/***
 	 * Handles list of radio stations.
 	 * 
 	 * @author Martin Vysny
 	 */
 	private static class RadioListHandler extends DefaultHandler {
 		/***
 		 * Store the genres here.
 		 */
 		private final List<Radio> result;
 
 		/***
 		 * Creates new handler instance.
 		 * 
 		 * @param result
 		 *            store the genres here.
 		 */
 		public RadioListHandler(List<Radio> result) {
 			this.result = result;
 		}
 
 		@Override
 		public void startElement(String uri, String localName, String name,
 				Attributes attributes) {
 			if (Thread.currentThread().isInterrupted()) {
 				throw new RuntimeException("interrupted");
 			}
 			if (!localName.equals("station"))
 				return;
 			result.add(Radio.fromXML(attributes));
 		}
 	}
 
 	/***
 	 * Removes the ASCII graphics from the string start and end. Graphics in the
 	 * middle is left as-is. The string is trimmed as well.
 	 * 
 	 * @param string
 	 *            the string
 	 * @return trimmed string with ASCII graphics removed.
 	 */
 	public static String removeAsciiGraphics(final String string) {
 		if (MiscUtils.isEmpty(string))
 			return string;
 		int start, end;
 		for (start = 0; start < string.length(); start++) {
 			if (Character.isLetterOrDigit(string.charAt(start)))
 				break;
 		}
 		for (end = string.length() - 1; end >= 0; end--) {
 			if (Character.isLetterOrDigit(string.charAt(end)))
 				break;
 		}
 		if (start >= end)
 			return "";
 		return string.substring(start, end + 1);
 	}
 }