/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.frontend.xeditor;
  
  import java.io.IOException;
  import java.util.Map;
  
  import javax.xml.transform.TransformerFactory;
  
  import org.jdom2.Document;
  import org.jdom2.Element;
  import org.jdom2.JDOMException;
  import org.jdom2.Text;
  import org.jdom2.filter.Filters;
  import org.mycore.common.MCRClassTools;
  import org.mycore.common.config.MCRConfiguration2;
  import org.mycore.common.content.MCRContent;
  import org.mycore.common.content.MCRJDOMContent;
  import org.mycore.common.content.transformer.MCRContentTransformer;
  import org.mycore.common.content.transformer.MCRXSL2XMLTransformer;
  import org.mycore.common.xml.MCRXMLFunctions;
  import org.xml.sax.SAXException;
  
  /**
   * PostProcessor for MyCoRe editor framework
   * that allows execution of XSLT stylesheets after an editor is closed
   * 
   * &lt;xed:post-processor class="org.mycore.frontend.xeditor.MCRPostProcessorXSL" 
   *      xsl="editor/ir_xeditor2mods.xsl" transformer="saxon" /&gt;
   * 
   * You can specify with param xsl the stylesheet, which should be processed and 
   * you can specify with parm transformer the XSLStylesheetProcessor ('xalan' or 'saxon').
   * If no transformer is specified the default transformer will be used
   * (property: MCR.LayoutService.TransformerFactoryClass).
   */
  public class MCRPostProcessorXSL implements MCRXEditorPostProcessor {
  
      private String transformer;
  
      private String stylesheet;
  
      public Document process(Document xml) throws IOException, JDOMException, SAXException {
          if (stylesheet == null) {
              return xml.clone();
          }
  
          Class<? extends TransformerFactory> factoryClass = null;
          try {
              if ("xalan".equals(transformer)) {
                  factoryClass = MCRClassTools
                      .forName("org.apache.xalan.processor.TransformerFactoryImpl");
              }
              if ("saxon".equals(transformer)) {
                  factoryClass = MCRClassTools
                      .forName("net.sf.saxon.TransformerFactoryImpl");
              }
          } catch (ClassNotFoundException e) {
              //do nothing, use default
          }
  
          if (factoryClass == null) {
              factoryClass = MCRConfiguration2
                  .<TransformerFactory>getClass("MCR.LayoutService.TransformerFactoryClass").orElseThrow();
          }
  
          MCRContent source = new MCRJDOMContent(xml);
          MCRContent transformed = MCRXSL2XMLTransformer.getInstance(factoryClass, "xsl/" + stylesheet).transform(source);
          MCRContent normalized = new MCRNormalizeUnicodeTransformer().transform(transformed);
          return normalized.asXML();
      }
  
      @Override
      public void setAttributes(Map<String, String> attributeMap) {
          this.stylesheet = attributeMap.get("xsl");
          if (attributeMap.containsKey("transformer")) {
              this.transformer = attributeMap.get("transformer");
          }
      }
  
      public void setStylesheet(String stylesheet) {
          this.stylesheet = stylesheet;
      }
  }
 
 class MCRNormalizeUnicodeTransformer extends MCRContentTransformer {
 
     public MCRJDOMContent transform(MCRContent source) throws IOException {
         try {
             Element root = source.asXML().getRootElement().clone();
             for (Text text : root.getDescendants(Filters.text())) {
                 text.setText(MCRXMLFunctions.normalizeUnicode(text.getText()));
             }
             return new MCRJDOMContent(root);
         } catch (JDOMException | SAXException ex) {
             throw new IOException(ex);
         }
     }
 }