package org.apache.maven.doxia.linkcheck.validation;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.

  */

 import java.io.File;

 import java.io.IOException;

 import java.io.Reader;

 import java.util.Locale;

 import org.apache.maven.doxia.linkcheck.model.LinkcheckFileResult;

 import org.codehaus.plexus.util.IOUtil;

 import org.codehaus.plexus.util.ReaderFactory;

 import org.codehaus.plexus.util.StringUtils;

 import org.codehaus.plexus.util.WriterFactory;

 /**

  * A link validator solely for files on the local filesystem.

  *

  * @author <a href="mailto:bwalding@apache.org">Ben Walding</a>

  * @author <a href="mailto:aheritier@apache.org">Arnaud Heritier</a>

  * @version $Id: FileLinkValidator.java 1030039 2010-11-02 13:33:03Z ltheussl $

  */

 public final class FileLinkValidator

     implements LinkValidator

 {

     private String encoding;

     /**

      * @param encoding the encoding file used. If empty, using UTF-8.

      */

     public FileLinkValidator( String encoding )

     {

         if ( StringUtils.isEmpty( encoding ) )

         {

             encoding = WriterFactory.UTF_8;

         }

         this.encoding = encoding;

     }

     /** {@inheritDoc} */

     public LinkValidationResult validateLink( LinkValidationItem lvi )

     {

         File f = getFile( lvi );

         if ( f.exists() )

         {

             return new LinkValidationResult( LinkcheckFileResult.VALID_LEVEL, false, "" );

         }

         return new LinkValidationResult( LinkcheckFileResult.ERROR_LEVEL, false, "doesn't exist." );

     }

     /** {@inheritDoc} */

     public Object getResourceKey( LinkValidationItem lvi )

     {

         String link = lvi.getLink();

         // If we find an http(s) link or a mail link, it's not good

         // links starting with "/" should have a base URL pre-pended and be handled by OnlineHTTPLinkValidator.

         if ( link.toLowerCase( Locale.ENGLISH ).startsWith( "http://" )

             || link.toLowerCase( Locale.ENGLISH ).startsWith( "https://" ) || link.indexOf( '@' ) != -1

             || link.startsWith( "/" ) )

         {

             return null;

         }

         return getFile( lvi ).getAbsolutePath();

     }

     // ----------------------------------------------------------------------

     // Private methods

     // ----------------------------------------------------------------------

     /**

      * Returns the link of the given LinkValidationItem as a File.

      *

      * @param lvi The LinkValidationItem.

      * @return File the link as a File.

      */

     private File getFile( LinkValidationItem lvi )

     {

         String link = lvi.getLink();

         if ( link.indexOf( '#' ) != -1 )

         {

             String anchor = link.substring( link.indexOf( '#' ) + 1 );

             link = link.substring( 0, link.indexOf( '#' ) );

             // If the link was just #fred or similar, then the file is the file it came from

             if ( link.trim().length() == 0 ) // in the same file

             {

                 // the anchor exists?

                 String content = read( lvi.getSource(), encoding );

                 if ( Anchors.matchesAnchor( content, anchor ) )

                 {

                     return lvi.getSource();

                 }

                 // return an invalid file

                 return new File( lvi.getLink() );

             }

             // the anchor exists?

             String content = read( new File( lvi.getSource().getParentFile(), link ), encoding );

             if ( Anchors.matchesAnchor( content, anchor ) )

             {

                 return new File( lvi.getSource().getParentFile(), link );

             }

             // return an invalid file

             return new File( lvi.getLink() );

         }

         if ( link.indexOf( '?' ) != -1 )

         {

             link = link.substring( 0, link.indexOf( '?' ) );

             // If the link was just ?param=something or similar, then the file is the file it came from

             // XXX: Theoretically we could even validate the anchor tag?

             if ( link.trim().length() == 0 )

             {

                 return lvi.getSource();

             }

         }

         return new File( lvi.getSource().getParentFile(), link );

     }

     /**

      * @param f not null

      * @param encoding the encoding file used

      * @return the content of the file or null if an error occurred.

      */

     private static String read( File f, String encoding )

     {

         Reader reader = null;

         try

         {

             reader = ReaderFactory.newReader( f, encoding );

             return IOUtil.toString( reader );

         }

         catch ( IOException e )

         {

             // nop;

         }

         finally

         {

             IOUtil.close( reader );

         }

         return null;

     }

 }