/***
    * Copyright 2003-2004 Fabrizio Giustina.
    * 
    * 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.maven.xhtml;
  
  import java.io.File;
  import java.io.IOException;
  
  import org.apache.tools.ant.Project;
  import org.dom4j.Element;
  import org.dom4j.io.XMLWriter;
  import org.dom4j.tree.DefaultElement;
  import org.xml.sax.EntityResolver;
  import org.xml.sax.ErrorHandler;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXParseException;
  
  /***
   * ValidatorHandler.
   * @author fgiust
   * @version $Revision: 1.4 $ ($Author: fgiust $)
   */
  class ValidatorHandler implements ErrorHandler, EntityResolver
  {
  
      /***
       * number of errors found in the current file.
       */
      private int errorsFound;
  
      /***
       * out.
       */
      private XMLWriter out;
  
      /***
       * real EntityResolver for DTDs
       */
      private EntityResolver chainedEntityResolver;
  
      /***
       * @return Returns the chainedEntityResolver.
       */
      public EntityResolver getChainedEntityResolver()
      {
          return this.chainedEntityResolver;
      }
  
      /***
       * @param chainedEntityResolver The chainedEntityResolver to set.
       */
      public void setChainedEntityResolver(EntityResolver chainedEntityResolver)
      {
          this.chainedEntityResolver = chainedEntityResolver;
      }
  
      /***
       * set XMLWriter for output.
       * @param writer XMLWriter
       */
      public void setOut(XMLWriter writer)
      {
          this.out = writer;
      }
  
      /***
       * init the validation handler: set up current file and reset errors number.
       * @param file File currently validated
       */
      public void init(File file)
      {
          this.errorsFound = 0;
      }
  
      /***
       * how many errors happened during last parsing?
       * @return int number of errors
       */
      public int getErrors()
      {
          return this.errorsFound;
      }
  
      /***
       * an error occurred: increment errors count and log exception message.
       * @param exception SAXParseException
      */
     public void error(SAXParseException exception)
     {
         this.errorsFound++;
         doLog(exception, Project.MSG_ERR);
     }
 
     /***
      * a fatal error occurred: redirect to error().
      * @param exception SAXParseException
      */
     public final void fatalError(SAXParseException exception)
     {
         error(exception);
     }
 
     /***
      * a warning occurred: redirect to error().
      * @param exception SAXParseException
      */
     public final void warning(SAXParseException exception)
     {
         error(exception);
     }
 
     /***
      * log event to output.
      * @param e SAXParseException
      * @param logLevel int
      */
     private void doLog(SAXParseException e, int logLevel)
     {
         Element error = new DefaultElement("error");
         error.addAttribute("line", "" + e.getLineNumber());
         error.addAttribute("col", "" + e.getColumnNumber());
         error.addAttribute("position", e.getLineNumber() + ":" + e.getColumnNumber());
         error.addAttribute("level", "" + logLevel);
 
         String message = e.getMessage();
         // check for invalid sequence ]]> and encode to be sure not to break the build
         int endCdata;
         while (message != null && (endCdata = message.indexOf("]]>")) > -1)
         {
             message = message.substring(0, endCdata) + "] ] >" + message.substring(endCdata + 3, message.length());
         }
 
         error.addCDATA(message);
         writeToLog(error);
     }
 
     /***
      * this method is not used to resolve entities, but to log dtd in files.
      * @param publicId public ID in dtd
      * @param systemId system ID in dtd
      * @return always null
      * @throws SAXException generated by chained EntityResolver
      * @throws IOException generated by chained EntityResolver
      */
     public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException
     {
         // log dtd info (not entities)
         if (systemId.indexOf(".dtd") != -1)
         {
             // "-//W3C//DTD XHTML 1.0 Transitional//EN"
             String name = publicId;
 
             if (name != null)
             {
                 int start = name.indexOf("-//W3C//DTD ");
                 int end = name.lastIndexOf("//EN");
 
                 if (start != -1 && end > (start + 12))
                 {
                     // DTD "friendly" name
                     name = name.substring(start + 12, end);
                 }
 
             }
 
             // write a "dtd" element to output
             Element dtd = new DefaultElement("dtd");
             dtd.addAttribute("publicId", publicId);
             dtd.addAttribute("systemId", systemId);
             dtd.addAttribute("display", name);
             writeToLog(dtd);
         }
 
         return chainedEntityResolver.resolveEntity(publicId, systemId);
     }
 
     /***
      * write an element to the xml log file.
      * @param element Element to write
      */
     private void writeToLog(Element element)
     {
         try
         {
             this.out.write(element);
         }
         catch (IOException e)
         {
             // ignore
         }
     }
 }