/**
    * Copyright 2011-2013 The Kuali Foundation Licensed under the Educational Community
    * License, Version 2.0 (the "License"); you may not use this file except in
    * compliance with the License. You may obtain a copy of the License at
    *
    * http://www.osedu.org/licenses/ECL-2.0
    *
    * Unless required by applicable law or agreed to in writing, software
    * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations under
   * the License.
   */
  package org.kuali.mobility.news.dao;
  
  import java.io.InputStreamReader;
  import java.io.UnsupportedEncodingException;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLEncoder;
  import java.util.ArrayList;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.log4j.Logger;
  import org.kuali.mobility.news.entity.NewsArticle;
  import org.kuali.mobility.news.entity.NewsSource;
  import org.springframework.context.ApplicationContext;
  import org.springframework.context.ApplicationContextAware;
  
  import com.sun.syndication.feed.synd.SyndEntryImpl;
  import com.sun.syndication.feed.synd.SyndFeed;
  import com.sun.syndication.io.ParsingFeedException;
  import com.sun.syndication.io.SyndFeedInput;
  
  /**
   * @author Kuali Mobility Team (mobility.collab@kuali.org)
   */
  public class NewsCacheImpl implements NewsCache, ApplicationContextAware {
  
  	private static final Logger LOG = Logger.getLogger(NewsCacheImpl.class);
  	private ApplicationContext applicationContext;
  	private Map<Long, NewsSource> newsSources;
  
  	public NewsCacheImpl() {
  		newsSources = new HashMap<Long, NewsSource>();
  	}
  
  	/**
  	 * Update the cache for a single NewsSource. Called when a NewsSource is
  	 * saved.
  	 *
  	 * @param source the NewsSource that was saved
  	 */
  	public void updateCache(NewsSource source) {
  		if (source.isActive()) {
  			LOG.debug("NewsSource " + source.getId() + " is active & will be refreshed.");
  			if (!getNewsSources().containsKey(source.getId())) {
  				getNewsSources().put(source.getId(), source);
  			}
  			updateSource(source);
  		} else {
  			LOG.debug("NewsSource is inactive & being removed.");
  			getNewsSources().remove(source.getId());
  		}
  	}
  
  	/**
  	 * Does the actual work of updating a news feed and its articles
  	 *
  	 * @param feed the NewsFeed to update
  	 * @param source the NewsSource that defines the feed to update
  	 */
  	@SuppressWarnings("unchecked")
  	public void updateSource(NewsSource source) {
  		if (source == null) {
  			LOG.error("Not updating, source is null.");
  			return;
  		} else if (source.getUrl() == null) {
  			LOG.debug("Not updating source due to no URL for source " + source.getId());
  			source.setTitle(source.getName());
  			return;
  		}
  
  		URL feedUrl = null;
  		try {
  			feedUrl = new URL(source.getUrl());
  		} catch (MalformedURLException e) {
  			LOG.error("Bad feed url: " + source.getUrl(), e);
  		}
  		SyndFeedInput input = new SyndFeedInput();
  		SyndFeed syndFeed = null;
  		try {
  			syndFeed = input.build(new InputStreamReader(feedUrl.openStream()));
  			if (syndFeed != null) {
  				LOG.debug("Feed data retrieved, populating articles for: " + syndFeed.getTitle());
  				source.setTitle(syndFeed.getTitle());
 				source.setAuthor(syndFeed.getAuthor());
 				source.setDescription(syndFeed.getDescription());
 
 				List<NewsArticle> articles = new ArrayList<NewsArticle>();
 				for (SyndEntryImpl entry : (List<SyndEntryImpl>) syndFeed.getEntries()) {
 					LOG.debug("Processing article: " + entry.getTitle());
 					NewsArticle article = (NewsArticle) getApplicationContext().getBean("newsArticle");
 
 					article.setTitle(entry.getTitle());
 					try {
 						article.setDescription(entry.getDescription().getValue());
 					} catch (NullPointerException npe) {
 						LOG.error("Description for " + entry.getTitle() + " is null.");
 						article.setDescription(null);
 					}
 					article.setLink(entry.getLink());
 					try {
 						article.setPublishDate(new Date(entry.getPublishedDate().getTime()));
 					} catch (Exception e) {
 						LOG.error("Error creating timestamp for article: " + entry.getTitle());
 						LOG.error(e.getLocalizedMessage());
 					}
 					article.setSourceId(source.getId());
 					try {
 						article.setArticleId(URLEncoder.encode(entry.getUri(), "UTF-8"));
 					} catch (UnsupportedEncodingException e) {
 						article.setArticleId(entry.getUri());
 					}
 
 					articles.add(article);
 				}
 				source.setArticles(articles);
 			} else {
 				source.setTitle(source.getName());
 			}
 		} catch(ParsingFeedException pfe ) {
 			LOG.error("Error parsing feed: " + source.getName());
 			LOG.error( pfe.getLocalizedMessage(), pfe );
 		} catch (Exception e) {
 			LOG.error("Error reading feed: " + source.getName(), e);
 		}
 
 	}
 
 	public ApplicationContext getApplicationContext() {
 		return applicationContext;
 	}
 
 	public void setApplicationContext(ApplicationContext applicationContext) {
 		this.applicationContext = applicationContext;
 	}
 
 	public Map<Long, NewsSource> getNewsSources() {
 		return newsSources;
 	}
 
 	public void setNewsSources(Map<Long, NewsSource> newsSources) {
 		this.newsSources = newsSources;
 	}
 }