/*
 * Copyright (C) 2003-2009 eXo Platform SAS.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Affero 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 org.exoplatform.wcm.connector.collaboration;

import java.io.ByteArrayInputStream;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.jcr.Node;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.dom.DOMSource;

import org.exoplatform.services.jcr.util.Text;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;
import org.exoplatform.services.rest.resource.ResourceContainer;
import org.exoplatform.services.wcm.core.WCMConfigurationService;
import org.exoplatform.services.wcm.publication.WCMComposer;
import org.exoplatform.services.wcm.utils.WCMCoreUtils;
import org.exoplatform.wcm.connector.BaseConnector;
import org.w3c.dom.Document;

import com.sun.syndication.feed.synd.SyndContent;
import com.sun.syndication.feed.synd.SyndContentImpl;
import com.sun.syndication.feed.synd.SyndEntry;
import com.sun.syndication.feed.synd.SyndEntryImpl;
import com.sun.syndication.feed.synd.SyndFeed;
import com.sun.syndication.feed.synd.SyndFeedImpl;
import com.sun.syndication.io.SyndFeedOutput;

/**
 * Generate an RSS feed.
 *
 * @author chuong_phan@exoplatform.com, phan.le.thanh.chuong@gmail.com
 * @since      29-08-2009
 * @copyright  eXo Platform SEA
 * 
 * @anchor ECMSref.DevelopersReferences.RestService_APIs_v1alpha1.RssConnector
 */
@Path("/feed/")
public class RssConnector extends BaseConnector implements ResourceContainer {

  /** The WORKSPACE. */
  static private String WORKSPACE = "workspace" ;

  /** The REPOSITORY. */
  static private String REPOSITORY = "repository" ;

  /** The RS s_ version. */
  static private String RSS_VERSION = "rss_2.0" ;

  /** The FEE d_ title. */
  static private String FEED_TITLE = "exo:feedTitle" ;

  /** The DESCRIPTION. */
  static private String DESCRIPTION = "exo:description" ;

  /** The TITLE. */
  static private String TITLE = "exo:title";

  /** The LINK. */
  static private String LINK = "exo:link" ;

  /** The SUMMARY. */
  static private String SUMMARY = "exo:summary";

  /** The detail page */
  static private String DETAIL_PAGE = "detail-page";

  /** The detail get param */
  static private String DETAIL_PARAM = "detail-param";

  /** The wcm composer service. */
  private WCMComposer wcmComposer;

  /** The wcm configuration service. */
  private WCMConfigurationService wcmConfigurationService;
  /** The log. */
  private static final Log LOG = ExoLogger.getLogger(RssConnector.class.getName());

  /**
   * Instantiate a new RSS connector.
   *
   * @param container The container
   */
  public RssConnector() {
    this.wcmConfigurationService = WCMCoreUtils.getService(WCMConfigurationService.class);    
    this.wcmComposer = WCMCoreUtils.getService(WCMComposer.class);
  }

  /**
   * Generate an RSS feed.
   *
   * @param repositoryName The name of repository
   * @param workspaceName The name of workspace
   * @param server The server
   * @param siteName The name of site
   * @param categoryPath The path of category
   *
   * @return The response
   *
   * @throws Exception The exception
   * 
   * @anchor ECMSref.DevelopersReferences.RestService_APIs_v1alpha1.RssConnector.generate
   */
  @GET
  @Path("/rss/")
  public Response generate(@QueryParam("repository") String repositoryName,
                           @QueryParam("workspace") String workspaceName,
                           @QueryParam("server") String server,
                           @QueryParam("siteName") String siteName,
                           @QueryParam("title") String title,
                           @QueryParam("desc") String desc,
                           @QueryParam("folderPath") String folderPath,
                           @QueryParam("orderBy") String orderBy,
                           @QueryParam("orderType") String orderType,
                           @QueryParam("lang") String lang,
                           @QueryParam("detailPage") String detailPage,
                           @QueryParam("detailParam") String detailParam,
                           @QueryParam("recursive") String recursive) throws Exception {

    Map<String, String> contextRss = new HashMap<String, String>();
    contextRss.put(REPOSITORY, repositoryName);
    contextRss.put(WORKSPACE, workspaceName);
    contextRss.put(RSS_VERSION, "rss_2.0");
    contextRss.put(FEED_TITLE, title);
    if (desc == null)
      desc = "Powered by eXo WCM-" + WCMCoreUtils.getProjectVersion();
    contextRss.put(DESCRIPTION, desc);

    contextRss.put(LINK, server);

    if (detailPage == null)
      detailPage = wcmConfigurationService.getRuntimeContextParam(WCMConfigurationService.PARAMETERIZED_PAGE_URI);
    contextRss.put(DETAIL_PAGE, detailPage);
    if (detailParam == null) detailParam  = "content-id";
    contextRss.put(DETAIL_PARAM, detailParam);


    HashMap<String, String> filters = new HashMap<String, String>();
    filters.put(WCMComposer.FILTER_MODE, WCMComposer.MODE_LIVE);
    if (orderType == null) orderType = "DESC";
    if (orderBy == null) orderBy = "publication:liveDate";
    if (lang == null) lang = "en";
    filters.put(WCMComposer.FILTER_ORDER_BY, orderBy);
    filters.put(WCMComposer.FILTER_ORDER_TYPE, orderType);
    filters.put(WCMComposer.FILTER_LANGUAGE, lang);
    filters.put(WCMComposer.FILTER_RECURSIVE, recursive);

    String path=null;
    if (folderPath!=null) {
      path = folderPath;
    }


    List<Node> nodes = wcmComposer.getContents(workspaceName,
                                               path,
                                               filters,
                                               WCMCoreUtils.getUserSessionProvider());

    String feedXML = generateRSS(nodes, contextRss);

    Document document = DocumentBuilderFactory.newInstance()
                                              .newDocumentBuilder()
                                              .parse(new ByteArrayInputStream(feedXML.getBytes()));

    DateFormat dateFormat = new SimpleDateFormat(IF_MODIFIED_SINCE_DATE_FORMAT);
    Response response = Response.ok(new DOMSource(document), MediaType.TEXT_XML)
                                .header(LAST_MODIFIED_PROPERTY, dateFormat.format(new Date()))
                                .build();
    return response;
  }
  
  

  /**
   * Generate an RSS feed.
   *
   * @param context The context
   *
   * @return The string
   */
  private String generateRSS(List<Node> nodes , Map<String, String> context) {
    String rssVersion = context.get(RSS_VERSION) ;
    String feedTitle = context.get(FEED_TITLE) ;
    String feedDescription = context.get(DESCRIPTION) ;
    String feedLink = context.get(LINK) ;
    String detailPage = context.get(DETAIL_PAGE) ;
    String detailParam = context.get(DETAIL_PARAM) ;
    String repository = context.get(REPOSITORY) ;
    String workspace = context.get(WORKSPACE) ;
    String contentUrl;
    if (!feedLink.endsWith("/")) {
      contentUrl = feedLink + "/" + detailPage + "?" + detailParam + "=/" + repository + "/"
          + workspace;
    } else {
      contentUrl = feedLink + detailPage + "?" + detailParam + "=/" + repository + "/" + workspace;
    }

    if(feedTitle == null || feedTitle.length() == 0) feedTitle = "" ;
    try {

      SyndFeed feed = new SyndFeedImpl();
      feed.setFeedType(rssVersion);
      feed.setTitle(feedTitle.replaceAll("&nbsp;", " "));
      feed.setLink(feedLink);
      feed.setDescription(feedDescription.replaceAll("&nbsp;", " "));
      feed.setEncoding("UTF-8");

      List<SyndEntry> entries = new ArrayList<SyndEntry>();
      Iterator<Node> iter = nodes.iterator();
      while (iter.hasNext()) {
        Node node = iter.next();
        
        StringBuilder url= new StringBuilder();
        url.append(contentUrl);
        if (node.isNodeType("nt:frozenNode")) {
          String uuid = node.getProperty("jcr:frozenUuid").getString();
          Node originalNode = node.getSession().getNodeByUUID(uuid);
          url.append(originalNode.getPath());
          url.append("&version=");
          url.append(node.getParent().getName());
        } else {
          url.append(node.getPath());
        }
        
        SyndEntry entry = new SyndEntryImpl();

        if (node.hasProperty(TITLE)) {
          String nTitle = node.getProperty(TITLE).getString();
          //encoding
          nTitle = new String(nTitle.getBytes("UTF-8"));
          entry.setTitle(Text.encodeIllegalXMLCharacters(nTitle));
        }
        else entry.setTitle("") ;

        entry.setLink(url.toString());
        SyndContent description = new SyndContentImpl();
        description.setType("text/plain");

        if (node.hasProperty(SUMMARY))
          description.setValue(Text.encodeIllegalXMLCharacters(node.getProperty(SUMMARY)
                                                                   .getString())
                                   .replaceAll("&nbsp;", " "));
        else
          description.setValue("");

        entry.setDescription(description);
        entries.add(entry);
        entry.getEnclosures() ;
      }
      feed.setEntries(entries);

      SyndFeedOutput output = new SyndFeedOutput();
      return output.outputString(feed);
    } catch (Exception e) {
      if (LOG.isErrorEnabled()) {
        LOG.error("Error when perform generateRSS: ", e);
      }
    }
    return null;
  }

  /* (non-Javadoc)
   * @see org.exoplatform.wcm.connector.BaseConnector#getContentStorageType()
   */
  protected String getContentStorageType() throws Exception {
    return null;
  }

  /* (non-Javadoc)
   * @see org.exoplatform.wcm.connector.BaseConnector#getRootContentStorage(javax.jcr.Node)
   */
  protected Node getRootContentStorage(Node node) throws Exception {
    return null;
  }
}
