/**
    * This file Copyright (c) 2015 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.module.cache.cachepolicy;
  
  import info.magnolia.cms.cache.CacheConstants;
  import info.magnolia.module.cache.cachekey.CacheKeyGenerator;
  import info.magnolia.objectfactory.Components;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Request attribute with additional cache informations retrieved from {@link CacheConstants#HEADER_X_MAGNOLIA_CACHE}.
   */
  public class XMagnoliaCacheAttribute {
  
      private static Logger log = LoggerFactory.getLogger(XMagnoliaCacheAttribute.class);
  
      public static final String NAME = CacheConstants.HEADER_X_MAGNOLIA_CACHE;
  
      private Integer ttl;
      private CacheKeyGenerator keyGenerator;
  
      public XMagnoliaCacheAttribute(HttpServletRequest request) {
          String header = request.getHeader(CacheConstants.HEADER_X_MAGNOLIA_CACHE);
          if (header != null) {
              try {
                  if (header.contains(CacheKeyGenerator.class.getSimpleName())) {
                      String cacheKeyGeneratorClass = StringUtils.substringBetween(header, CacheKeyGenerator.class.getSimpleName() + "=", ",");
                      if (StringUtils.isNotEmpty(cacheKeyGeneratorClass)) {
                          Class clazz = Class.forName(cacheKeyGeneratorClass);
                          if (CacheKeyGenerator.class.isAssignableFrom(clazz)) {
                              keyGenerator = (CacheKeyGenerator) Components.newInstance(clazz);
                          } else {
                              log.error("Cannot use cache key generator: '{}'. Expected instance of '{}'", clazz, CacheKeyGenerator.class);
                          }
                      }
                  }
                  if (header.contains(CacheConstants.HEADER_VALUE_X_MAGNOLIA_TTL)) {
                      ttl = Integer.parseInt(StringUtils.substringBetween(header, CacheConstants.HEADER_VALUE_X_MAGNOLIA_TTL + "=", ","));
                  }
              } catch (NumberFormatException e) {
                  log.error("Unparsable TTL in '{}' header: {}", CacheConstants.HEADER_X_MAGNOLIA_CACHE, header);
              } catch (ClassNotFoundException e) {
                  log.warn("Cannot use custom cache key generator class:", e);
              }
          }
      }
  
      public Integer getTtl() {
          return ttl;
      }
  
      public CacheKeyGenerator getKeyGenerator() {
          return keyGenerator;
      }
  }