/*
    * 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.
   */
  package org.apache.maven.plugins.shade.resource;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.StringReader;
  import java.util.Iterator;
  import java.util.List;
  import java.util.jar.JarEntry;
  import java.util.jar.JarOutputStream;
  
  import org.apache.maven.plugins.shade.relocation.Relocator;
  import org.jdom2.Attribute;
  import org.jdom2.Content;
  import org.jdom2.Document;
  import org.jdom2.Element;
  import org.jdom2.JDOMException;
  import org.jdom2.input.SAXBuilder;
  import org.jdom2.output.Format;
  import org.jdom2.output.XMLOutputter;
  import org.xml.sax.EntityResolver;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  
  /**
   * Appends multiple occurrences of some XML file.
   */
  public class XmlAppendingTransformer extends AbstractCompatibilityTransformer {
      public static final String XSI_NS = "http://www.w3.org/2001/XMLSchema-instance";
  
      boolean ignoreDtd = true;
  
      String resource;
  
      Document doc;
  
      private long time = Long.MIN_VALUE;
  
      @Override
      public boolean canTransformResource(String r) {
          return resource != null && resource.equalsIgnoreCase(r);
      }
  
      @Override
      public void processResource(String resource, InputStream is, List<Relocator> relocators, long time)
              throws IOException {
          Document r;
          try {
              SAXBuilder builder = new SAXBuilder(false);
              builder.setExpandEntities(false);
              if (ignoreDtd) {
                  builder.setEntityResolver(new EntityResolver() {
                      @Override
                      public InputSource resolveEntity(String publicId, String systemId)
                              throws SAXException, IOException {
                          return new InputSource(new StringReader(""));
                      }
                  });
              }
              r = builder.build(is);
          } catch (JDOMException e) {
              throw new RuntimeException("Error processing resource " + resource + ": " + e.getMessage(), e);
          }
  
          if (doc == null) {
              doc = r;
          } else {
              Element root = r.getRootElement();
  
              for (Iterator<Attribute> itr = root.getAttributes().iterator(); itr.hasNext(); ) {
                  Attribute a = itr.next();
                  itr.remove();
  
                  Element mergedEl = doc.getRootElement();
                  Attribute mergedAtt = mergedEl.getAttribute(a.getName(), a.getNamespace());
                  if (mergedAtt == null) {
                      mergedEl.setAttribute(a);
                  }
              }
  
              for (Iterator<Element> itr = root.getChildren().iterator(); itr.hasNext(); ) {
                  Content n = itr.next();
                 itr.remove();
 
                 doc.getRootElement().addContent(n);
             }
         }
 
         if (time > this.time) {
             this.time = time;
         }
     }
 
     @Override
     public boolean hasTransformedResource() {
         return doc != null;
     }
 
     @Override
     public void modifyOutputStream(JarOutputStream jos) throws IOException {
         JarEntry jarEntry = new JarEntry(resource);
         jarEntry.setTime(time);
         jos.putNextEntry(jarEntry);
 
         new XMLOutputter(Format.getPrettyFormat()).output(doc, jos);
 
         doc = null;
     }
 }