/*

  * Copyright (c) 2003-2011, Simon Brown

  * 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 Pebble 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 net.sourceforge.pebble.event.response;

 import net.sourceforge.pebble.PluginProperties;

 import net.sourceforge.pebble.domain.Comment;

 import net.sourceforge.pebble.domain.Response;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 /**

  * Checks comment and TrackBack content for a large number of links and sets

  * the state of such responses to pending.

  *

  * @author Simon Brown

  */

 public class LinkSpamListener extends BlogEntryResponseListenerSupport {

   /** the log used by this class */

   private static final Log log = LogFactory.getLog(LinkSpamListener.class);

   /** the pattern used to find HTML links */

   private static final Pattern HTML_LINK_PATTERN = Pattern.compile("<a.*?href=.*?>", Pattern.CASE_INSENSITIVE | Pattern.DOTALL);

   /** the default threshold for the number of links allowed */

   public static final int DEFAULT_THRESHOLD = 3;

   /** the name of the threshold property for comments */

   public static final String COMMENT_THRESHOLD_KEY = "LinkSpamListener.commentThreshold";

   /** the name of the threshold property for TrackBacks */

   public static final String TRACKBACK_THRESHOLD_KEY = "LinkSpamListener.trackbackThreshold";

   /**

    * Called when a comment or TrackBack has been added.

    *

    * @param response a Response

    */

   protected void blogEntryResponseAdded(Response response) {

     String content = response.getContent();

     if (content != null) {

       Matcher m = HTML_LINK_PATTERN.matcher(content);

       int count = 0;

       while (m.find()) {

         count++;

       }

       PluginProperties props = response.getBlogEntry().getBlog().getPluginProperties();

       String propertyName = "";

       if (response instanceof Comment) {

         propertyName = COMMENT_THRESHOLD_KEY;

       } else {

         propertyName = TRACKBACK_THRESHOLD_KEY;

       }

       int threshold = DEFAULT_THRESHOLD;

       if (props.hasProperty(propertyName)) {

         try {

           threshold = Integer.parseInt(props.getProperty(propertyName));

         } catch (NumberFormatException nfe) {

           log.error(nfe.getMessage());

           // do nothing, the value has already been defaulted

         }

       }

       if (count > threshold) {

         log.info(response.getTitle() + " marked as pending : number of links is " + count + ", threshold is " + threshold);

         response.setPending();

         response.incrementSpamScore();

       }

     }

   }

 }