/**
    * This file Copyright (c) 2010-2015 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.blossom.support;
  
  import java.util.Enumeration;
  import java.util.NoSuchElementException;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletRequestWrapper;
  
  /**
   * Request wrapper for overriding special attributes.
   *
   * @since 1.2
   */
  public class SpecialAttributeRequestWrapper extends HttpServletRequestWrapper {
  
      private String commonPrefix;
      private String[] names;
      private Object[] values;
      private boolean enabled = true;
  
      public SpecialAttributeRequestWrapper(HttpServletRequest request) {
          super(request);
      }
  
      public boolean isEnabled() {
          return enabled;
      }
  
      public void setEnabled(boolean enabled) {
          this.enabled = enabled;
      }
  
      protected void setOverriddenAttributes(String commonPrefix, String[] names, Object[] values) {
          this.commonPrefix = commonPrefix;
          this.names = names;
          this.values = values;
      }
  
      @Override
      public Object getAttribute(String name) {
          if (enabled && name.startsWith(commonPrefix)) {
              for (int i = 0; i < names.length; i++) {
                  if (names[i].equals(name)) {
                      return values[i];
                  }
              }
          }
          return super.getAttribute(name);
      }
  
      public Enumeration getAttributeNames() {
  
          if (!enabled) {
              return super.getAttributeNames();
          }
  
          return new Enumeration() {
  
              private int pos = 0;
              private String next = null;
              private Enumeration parentEnumeration = SpecialAttributeRequestWrapper.super.getAttributeNames();
  
              @Override
              public boolean hasMoreElements() {
                  if (next != null) {
                      return true;
                 }
                 while (pos < names.length) {
                     if (values[pos] != null) {
                         next = names[pos++];
                         return true;
                     }
                     pos++;
                 }
                 while (parentEnumeration.hasMoreElements()) {
                     String name = (String) parentEnumeration.nextElement();
                     if (!isAttributeOverridden(name)) {
                         next = name;
                         return true;
                     }
                 }
                 return false;
             }
 
             @Override
             public String nextElement() {
                 if (next != null) {
                     String value = next;
                     next = null;
                     return value;
                 }
                 while (pos < names.length) {
                     if (values[pos] != null) {
                         return names[pos++];
                     }
                     pos++;
                 }
                 while (parentEnumeration.hasMoreElements()) {
                     String name = (String) parentEnumeration.nextElement();
                     if (!isAttributeOverridden(name)) {
                         return name;
                     }
                 }
                 throw new NoSuchElementException();
             }
         };
     }
 
     @Override
     public void setAttribute(String name, Object o) {
         if (enabled && isAttributeOverridden(name)) {
             return;
         }
         super.setAttribute(name, o);
     }
 
     @Override
     public void removeAttribute(String name) {
         if (enabled && isAttributeOverridden(name)) {
             return;
         }
         super.removeAttribute(name);
     }
 
     private boolean isAttributeOverridden(String name) {
         if (name.startsWith(commonPrefix)) {
             for (String overriddenName : names) {
                 if (name.equals(overriddenName)) {
                     return true;
                 }
             }
         }
         return false;
     }
 }