package org.apache.maven.doxia.linkcheck;

 /*

  * 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 java.util.Set;

 import java.util.TreeSet;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 import org.codehaus.plexus.util.IOUtil;

 import org.codehaus.plexus.util.ReaderFactory;

 /**

  * Link matcher. Reads the contents of a file and tries to match the following:

  * <pre>

  * <a href="".../>

  * <link href="".../>

  * <img src="".../>

  * <script src="".../>

  * </pre>

  *

  * @author <a href="mailto:mac@apache.org">Ignacio G. Mac Dowell </a>

  * @version $Id: LinkMatcher.java 800044 2009-08-02 12:28:50Z vsiveton $

  */

 class LinkMatcher

 {

     /** Regexp for link matching. */

     private static final Pattern MATCH_PATTERN =

         Pattern.compile( "<(?>link|a|img|script)[^>]*?(?>href|src)\\s*?=\\s*?[\\\"'](.*?)[\\\"'][^>]*?",

                          Pattern.CASE_INSENSITIVE );

     /** No need to create a new object each time a file is processed. Just clear it. */

     private static final Set LINK_LIST = new TreeSet();

     private LinkMatcher()

     {

         // nop

     }

     /**

      * Reads a file and returns its contents without any XML comments.

      *

      * @param file the file we are reading

      * @param encoding the encoding file used

      * @return a StringBuffer with file's contents.

      * @throws IOException if something goes wrong.

      * @see ReaderFactory#newReader(File, String)

      * @see IOUtil#toString(Reader)

      */

     private static String toString( File file, String encoding )

         throws IOException

     {

         String content;

         Reader reader = null;

         try

         {

             reader = ReaderFactory.newReader( file, encoding );

             content = IOUtil.toString( reader );

         }

         finally

         {

             IOUtil.close( reader );

         }

         // some link could be in comments, remove them

         return content.replaceAll( "(?s)<!--.*?-->", "" );

     }

     /**

      * Performs the actual matching.

      *

      * @param file the file to check

      * @param encoding the encoding file used

      * @return a set with all links to check

      * @throws IOException if something goes wrong

      */

     static Set match( File file, String encoding )

         throws IOException

     {

         LINK_LIST.clear();

         final Matcher m = MATCH_PATTERN.matcher( toString( file, encoding ) );

         String link;

         while ( m.find() )

         {

             link = m.group( 1 ).trim();

             if ( link.length() < 1 )

             {

                 continue;

             }

             else if ( link.toLowerCase( Locale.ENGLISH ).indexOf( "javascript" ) != -1 )

             {

                 continue;

             }

             // TODO: Review dead code and delete if not needed

             // else if (link.toLowerCase( Locale.ENGLISH ).indexOf("mailto:") != -1) {

             // continue;

             // }

             LINK_LIST.add( link );

         }

         return LINK_LIST;

     }

 }