/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited

  *

  * Licensed under the Apache 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.apache.org/licenses/LICENSE-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.acegisecurity.captcha;

 import org.acegisecurity.ConfigAttribute;

 import org.acegisecurity.ConfigAttributeDefinition;

 import org.acegisecurity.context.SecurityContextHolder;

 import org.acegisecurity.intercept.web.FilterInvocation;

 import org.acegisecurity.securechannel.ChannelEntryPoint;

 import org.acegisecurity.securechannel.ChannelProcessor;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.springframework.beans.factory.InitializingBean;

 import org.springframework.util.Assert;

 import java.io.IOException;

 import java.util.Iterator;

 import javax.servlet.ServletException;

 /**

  * <p>CaptchaChannel template : Ensures the user has enough human privileges by review of the {@link

  * CaptchaSecurityContext} and using an abstract routine {@link

  * #isContextValidConcerningHumanity(CaptchaSecurityContext)} (implemented by sub classes)</p>

  *  <P>The component uses 2 main parameters for its configuration :

  *  <ul>

  *      <li>a keyword to be mapped to urls in the {@link

  *      org.acegisecurity.securechannel.ChannelProcessingFilter} configuration<br>

  *      default value provided by sub classes.</li>

  *      <li>and a thresold : used by the routine {@link

  *      #isContextValidConcerningHumanity(CaptchaSecurityContext)} to evaluate whether the {@link

  *      CaptchaSecurityContext} is valid default value = 0</li>

  *  </ul>

  *  </p>

  *

  * @author marc antoine Garrigue

  * @version $Id: CaptchaChannelProcessorTemplate.java 1496 2006-05-23 13:38:33Z benalex $

  */

 public abstract class CaptchaChannelProcessorTemplate implements ChannelProcessor, InitializingBean {

     //~ Instance fields ================================================================================================

     private ChannelEntryPoint entryPoint;

     protected Log logger = LogFactory.getLog(this.getClass());

     private String keyword = null;

     private int thresold = 0;

     //~ Methods ========================================================================================================

     /**

      * Verify if entryPoint and keyword are ok

      *

      * @throws Exception if not

      */

     public void afterPropertiesSet() throws Exception {

         Assert.notNull(entryPoint, "entryPoint required");

         Assert.hasLength(keyword, "keyword required");

     }

     public void decide(FilterInvocation invocation, ConfigAttributeDefinition config)

         throws IOException, ServletException {

         if ((invocation == null) || (config == null)) {

             throw new IllegalArgumentException("Nulls cannot be provided");

         }

         CaptchaSecurityContext context = null;

         context = (CaptchaSecurityContext) SecurityContextHolder.getContext();

         Iterator iter = config.getConfigAttributes();

         while (iter.hasNext()) {

             ConfigAttribute attribute = (ConfigAttribute) iter.next();

             if (supports(attribute)) {

                 logger.debug("supports this attribute : " + attribute);

                 if (!isContextValidConcerningHumanity(context)) {

                     logger.debug("context is not allowed to access ressource, redirect to captcha entry point");

                     redirectToEntryPoint(invocation);

                 } else {

                     logger.debug("has been successfully checked this keyword, increment request count");

                     context.incrementHumanRestrictedRessoucesRequestsCount();

                 }

             } else {

                 logger.debug("do not support this attribute");

             }

         }

     }

     public ChannelEntryPoint getEntryPoint() {

         return entryPoint;

     }

     public String getKeyword() {

         return keyword;

     }

     public int getThresold() {

         return thresold;

     }

     abstract boolean isContextValidConcerningHumanity(CaptchaSecurityContext context);

     private void redirectToEntryPoint(FilterInvocation invocation)

         throws IOException, ServletException {

         if (logger.isDebugEnabled()) {

             logger.debug("context is not valid : redirecting to entry point");

         }

         entryPoint.commence(invocation.getRequest(), invocation.getResponse());

     }

     public void setEntryPoint(ChannelEntryPoint entryPoint) {

         this.entryPoint = entryPoint;

     }

     public void setKeyword(String keyword) {

         this.keyword = keyword;

     }

     public void setThresold(int thresold) {

         this.thresold = thresold;

     }

     public boolean supports(ConfigAttribute attribute) {

         if ((attribute != null) && (keyword.equals(attribute.getAttribute()))) {

             return true;

         } else {

             return false;

         }

     }

 }