/*
    * Copyright 2000-2001,2004 The Apache Software Foundation.
    * 
    * 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.apache.jetspeed.util.rewriter;
  
  
  // java.io
  import java.io.Reader;
  
  // java.net
  import java.net.MalformedURLException;
  
  // this makes it dependent on Swing...need an abstraction WTP
  import javax.swing.text.html.HTML;
  import javax.swing.text.MutableAttributeSet;
  
  /***
   *
   * Sample of extending HTML Rewriter for your specific needs
   *
   *
   * @author <a href="mailto:taylor@apache.org">David Sean Taylor</a>
   * @version $Id: SampleRewriter.java,v 1.5 2004/02/23 03:18:59 jford Exp $
   */
  
  public class SampleRewriter extends HTMLRewriter
  {
      private boolean debug = false;
      private String basePortalURL;
      private String fullPortalURL;
      private String sampleURL;
  
      private String sessionID = "NONE";
      private String formID = "NONE";
      private boolean sampleEndFlag = false;
  
      public String getSessionID()
      {
          return sessionID;
      }
  
      public String getFormID()
      {
          return formID;
      }
  
      public boolean getSampleEndFlag()
      {
          return sampleEndFlag;
      }
  
      /*
       * Basic constructor for creating a Sample Rewriter.
       *
       * @param basePortalURL Base Portal URL
       * @param fullPortalURL  Full Portal URL with path parameters and query strings (sessionid)
       * @param sampleURL  The sample URL.
       *
       */
      public SampleRewriter(String basePortalURL, String fullPortalURL, String sampleURL )
      {
          this.basePortalURL = basePortalURL;
          this.fullPortalURL = fullPortalURL;
          this.sampleURL = sampleURL;
      }
  
      /*
       * Entry point into rewriting HTML content.
       *
       * Reads stream from proxied host, runs configured HTML parser against that stream,
       * rewriting relevant links, and writes the parsed stream back to the client.
       *
       * @param input the HTML input stream.
       * @param baseURL the base URL of the target host.
       * @return the rewritten HTML output stream.
       *
       * @exception MalformedURLException a servlet exception.
       */
  
      public String rewrite(Reader input, String baseURL)
                                 throws MalformedURLException
      {
          String rewrittenHTML = "";
          this.basePortalURL = baseURL;
  
          HTMLParserAdaptor parser = new SwingParserAdaptor(this);
         rewrittenHTML = parser.run(input);
 
         return rewrittenHTML;
     }
 
     /*
      * <p>
      * This callback is called by the HTMLParserAdaptor implementation to write
      * back all rewritten URLs to point to the proxy server. The MMS implementation
      * writes specifically for network element ids and relative paths to MMS
      * resources.
      * </p>
      * <p>
      * Given the targetURL, rewrites the link as a link back to the proxy server.
      * </p>
      *
      * Example format:
      *
      *   http://proxyserver/proxy?neid=id?nepath=path
      *
      * @param targetURL the URL to be rewritten back to the proxy server.
      * @param baseURL the base URL of the target host.
      * @param proxyURL the base URL of the proxy server.
      * @return the rewritten URL to the proxy server.
      *
      * @exception MalformedURLException a servlet exception.
      */
     public String generateNewUrl(String targetURL, HTML.Tag tag, HTML.Attribute attribute)
     {
         if (debug)
             System.out.println("[rewriter] Tag: " + tag.toString() + "  Attribute: " + attribute.toString() + "  targetURL: " + targetURL + "  target = " + fullPortalURL + "]");
 
         // The only URL we want to re-write is ACTION attribute of the <FORM> tag.
         // Ignore all others
         if (tag == HTML.Tag.FORM && attribute == HTML.Attribute.ACTION) {
 
             // Strip the session Id value out of the ACTION attribute value
             int sessionLocation = targetURL.indexOf( "?sessionId" );
             if (sessionLocation > -1) {
                 int equalsLocation = targetURL.indexOf( "=", sessionLocation );
                 if (equalsLocation > -1) {
                     int ampLocation = targetURL.indexOf( "&", equalsLocation );
                     if (ampLocation > -1) {
                         sessionID = targetURL.substring( equalsLocation + 1, ampLocation );
                     } else {
                         sessionID = targetURL.substring( equalsLocation + 1 );
                     }
                 }
             }
 
             if (sampleEndFlag) {
                 // The sample session is being terminated, make the form action return to the portal home page
                 return basePortalURL;
             } else {
                 // Make the form action run the same portal page
                 return fullPortalURL;
             }
         }
 
         // This is a tag that we do not wish to re-write, return it's own value unmodified
         return targetURL;
     }
 
     /*
      * Returns true if all rewritten URLs should be sent back to the proxy server.
      *
      * @return true if all URLs are rewritten back to proxy server.
      */
     public boolean proxyAllTags()
     {
         return true;
     }
 
     /*
      * Start Tag Events
      */
     public String exitStartTagEvent(HTML.Tag tag, MutableAttributeSet attrs)
     {
         if (tag == HTML.Tag.FORM)
         {
             String inputTag = "<input type='hidden' name='sessionId' value='" + sessionID + "'/>";
             return inputTag;
         }
         return null;
     }
 
     /*
      * Simple Tag Events
      */
 
     public boolean enterSimpleTagEvent(HTML.Tag tag, MutableAttributeSet attrs)
     {
         if (tag == HTML.Tag.META)
         {
             Object o = attrs.getAttribute(HTML.Attribute.NAME);
             if (o != null)
             {
                 String s = o.toString();
                 if (s.equalsIgnoreCase("SampleEnd"))
                 {
                     sampleEndFlag = true;
                 }
             }
         }
         return true;
     }
 
 
     /*
      * Convert Tag Events
      */
 
     public void convertTagEvent(HTML.Tag tag, MutableAttributeSet attrs)
     {
         if (tag == HTML.Tag.FORM) {
            // All forms from sample will have the same form NAME.
            // Jetspeed will add its own FORM depending on the type of portlet
            // being used.  So if you have multiple forms, any Javascript will
            // have to know which form to reference.
            attrs.addAttribute("NAME","SampleForm");
         }
 
         // INPUT Tag
         if (tag == HTML.Tag.INPUT)
         {
             Object o = attrs.getAttribute(HTML.Attribute.NAME);
             if (o != null)
             {
                 String s = o.toString();
                 if (s.equalsIgnoreCase("FormID"))
                 {
                     o = attrs.getAttribute(HTML.Attribute.VALUE);
                     if (o != null)
                     {
                         formID = o.toString();
                     }
                 }
             }
         }
 
     }
 
 }