/*
    * Copyright (c) 2007, James Leigh All rights reserved.
    * 
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions are met:
    * 
    * - Redistributions of source code must retain the above copyright notice, this
    *   list of conditions and the following disclaimer.
    * - Redistributions in binary form must reproduce the above copyright notice,
   *   this list of conditions and the following disclaimer in the documentation
   *   and/or other materials provided with the distribution. 
   * - Neither the name of the openrdf.org nor the names of its contributors may
   *   be used to endorse or promote products derived from this software without
   *   specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   * 
   */
  package org.openrdf.elmo.example.rss;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.util.HashMap;
  import java.util.Map;
  
  import javax.servlet.GenericServlet;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.xml.namespace.QName;
  
  import org.openrdf.concepts.rdf.Seq;
  import org.openrdf.concepts.rss.Channel;
  import org.openrdf.concepts.rss.Item;
  import org.openrdf.elmo.ElmoManager;
  import org.openrdf.elmo.ElmoModule;
  import org.openrdf.elmo.sesame.SesameManager;
  import org.openrdf.elmo.sesame.SesameManagerFactory;
  import org.openrdf.elmo.sesame.roles.SesameEntity;
  import org.openrdf.rio.rss.RssWriter;
  
  /**
   * Creates an RSS feed from HTTP parameters or arguments.
   * 
   * @author James Leigh
   * 
   */
  public class App extends GenericServlet {
  	private static final long serialVersionUID = 1L;
  
  	private SesameManagerFactory factory;
  
  	@Override
  	public void init() throws ServletException {
  		factory = new SesameManagerFactory(new ElmoModule());
  	}
  
  	@Override
  	public void destroy() {
  		factory.close();
  	}
  
  	@Override
  	public void service(ServletRequest request, ServletResponse response)
  			throws IOException {
  		response.setContentType("application/rss+xml");
  		writeRss(response.getWriter(), request.getParameterMap());
  	}
  
  	public static void main(String[] args) throws IOException, ServletException {
  		Map<String, String[]> map = new HashMap<String, String[]>();
  		for (String arg : args) {
  			String[] e = arg.split("=", 2);
  			String[] v = map.get(e[0]);
  			if (v == null) {
  				map.put(e[0], new String[] { e[1] });
  			} else {
  				String[] p = new String[v.length + 1];
  				for (int i = 0; i < v.length; i++) {
  					p[i] = v[i];
  				}
  				p[v.length] = e[1];
  				map.put(e[0], p);
  			}
  		}
  		App app = new App();
  		app.init();
  		app.writeRss(new PrintWriter(System.out), map);
  		app.destroy();
 	}
 
 	private void writeRss(PrintWriter writer, Map parameterMap)
 			throws IOException {
 		SesameManager manager = factory.createElmoManager();
 		Channel channel = createChannel(manager, parameterMap);
 
 		RssWriter rss = new RssWriter(writer);
 		try {
 			rss.setConnection(manager.getConnection());
 			rss.startRDF();
 			rss.printChannel(((SesameEntity) channel).getSesameResource());
 			rss.endRDF();
 		} catch (Exception e) {
 			IOException io = new IOException(e.getMessage());
 			io.initCause(e);
 			throw io;
 		} finally {
 			rss.close();
 			manager.close();
 		}
 	}
 
 	private Channel createChannel(ElmoManager manager, Map parameterMap) {
 		String[] titles = (String[]) parameterMap.get("title");
 		String[] links = (String[]) parameterMap.get("link");
 		String[] descriptions = (String[]) parameterMap.get("description");
 		String[] subjects = (String[]) parameterMap.get("subject");
 
 		QName qname = new QName(links[0]);
 		Channel channel = manager.designate(Channel.class, qname);
 		channel.setRssTitle(titles[0]);
 		channel.getRssLinks().add(links[0]);
 		channel.setRssDescription(descriptions[0]);
 		channel.getDcSubjects().add(subjects[0]);
 
 		if (channel.getRssItems() != null) {
 			Seq<Item> list = channel.getRssItems();
 			for (Item item : list) {
 				manager.remove(item);
 			}
 			list.clear();
 			manager.remove(list);
 		}
 		Seq<Item> items = manager.designate(Seq.class);
 		channel.setRssItems(items);
 
 		for (int i = 1; i < titles.length; i++) {
 			Item item = manager.designate(Item.class, new QName(links[i]));
 			item.setRssTitle(titles[i]);
 			item.getRssLinks().add(links[i]);
 			item.setRssDescription(descriptions[i]);
 			items.add(item);
 		}
 
 		return channel;
 	}
 
 }