/*

  * Copyright (c) 2003-2011, Simon Brown

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   - Redistributions of source code must retain the above copyright

  *     notice, this list of conditions and the following disclaimer.

  *

  *   - Redistributions in binary form must reproduce the above copyright

  *     notice, this list of conditions and the following disclaimer in

  *     the documentation and/or other materials provided with the

  *     distribution.

  *

  *   - Neither the name of Pebble nor the names of its contributors may

  *     be used to endorse or promote products derived from this software

  *     without specific prior written permission.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

  * POSSIBILITY OF SUCH DAMAGE.

  */

 package net.sourceforge.pebble.decorator;

 import net.sourceforge.pebble.domain.BlogEntry;

 import net.sourceforge.pebble.domain.StaticPage;

 import net.sourceforge.pebble.util.StringUtils;

 import net.sourceforge.pebble.api.decorator.ContentDecoratorContext;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 /**

  * Escapes < and > tags in the excerpt/body of blog entries and

  * the body of static pages.

  * 

  * @author Simon Brown

  */

 public class EscapeMarkupDecorator extends ContentDecoratorSupport {

   private static final String ESCAPE_START_TAG = "<escape>";

   private static final String ESCAPE_END_TAG = "</escape>";

   /**

    * Decorates the specified blog entry.

    *

    * @param context   the context in which the decoration is running

    * @param blogEntry the blog entry to be decorated

    */

   public void decorate(ContentDecoratorContext context, BlogEntry blogEntry) {

     String escapedBody = escape(blogEntry.getBody());

     blogEntry.setBody(escapedBody);

     String escapedExcerpt = escape(blogEntry.getExcerpt());

     blogEntry.setExcerpt(escapedExcerpt);

   }

   /**

    * Decorates the specified static page.

    *

    * @param context    the context in which the decoration is running

    * @param staticPage the static page to be decorated

    */

   public void decorate(ContentDecoratorContext context, StaticPage staticPage) {

     String escapedBody = escape(staticPage.getBody());

     staticPage.setBody(escapedBody);

   }

   private String escape(String content) {

     // is there work to do?

     if (content == null || content.length() == 0) {

       return "";

     }

     // this pattern says "take the shortest match you can find where there are

     // one or more characters between escape tags"

     //  - the match is case insensitive and DOTALL means that newlines are

     //  - considered as a character match

     Pattern p = Pattern.compile(ESCAPE_START_TAG + ".+?" + ESCAPE_END_TAG,

         Pattern.CASE_INSENSITIVE | Pattern.DOTALL);

     Matcher m = p.matcher(content);

     // while there are blocks to be escaped

     while (m.find()) {

       int start = m.start();

       int end = m.end();

       // grab the text, strip off the escape tags and transform it

       String textToEscape = content.substring(start, end);

       textToEscape = textToEscape.substring(ESCAPE_START_TAG.length(), textToEscape.length() - ESCAPE_END_TAG.length());

       textToEscape = StringUtils.transformHTML(textToEscape);

       // now add it back into the original text

       content = content.substring(0, start) + textToEscape + content.substring(end, content.length());

       m = p.matcher(content);

     }

     return content;

   }

 }