/*
    * 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.myfaces.tobago.util;
  
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  import org.xml.sax.EntityResolver;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.parsers.ParserConfigurationException;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.StringReader;
  import java.util.Properties;
  
  public final class XmlUtils {
  
    public static String escape(final String s) {
      return escape(s, true);
    }
  
    public static String escape(final String s, final boolean isAttributeValue) {
      if (null == s) {
        return "";
      }
      int len = s.length();
      StringBuilder buffer = new StringBuilder(len);
      for (int i = 0; i < len; i++) {
        appendEntityRef(buffer, s.charAt(i), isAttributeValue);
      }
      return buffer.toString();
    }
  
    public static String escape(final char[] chars, final int offset, final int length, final boolean isAttributeValue) {
      if (null == chars) {
        return "";
      }
      StringBuilder buffer = new StringBuilder(length);
      for (int i = offset; i < length; i++) {
        appendEntityRef(buffer, chars[i], isAttributeValue);
      }
      return buffer.toString();
    }
  
    private static void appendEntityRef(final StringBuilder buffer, final char ch,
        final boolean isAttributeValue) {
      // Encode special XML characters into the equivalent character references.
      // These five are defined by default for all XML documents.
      switch (ch) {
        case '<':
          buffer.append("&lt;");
          break;
        case '&':
          buffer.append("&amp;");
          break;
        case '"': // need inside attributes values
          if (isAttributeValue) {
            buffer.append("&quot;");
          } else {
            buffer.append(ch);
          }
          break;
        case '\'': // need inside attributes values
          if (isAttributeValue) {
            buffer.append("&apos;");
          } else {
            buffer.append(ch);
          }
          break;
        case '>': // optional
          buffer.append("&gt;");
          break;
        default:
          buffer.append(ch);
      }
    }
  
   /** @deprecated */
   @Deprecated
   public static void load(final Properties properties, final InputStream stream)
       throws IOException {
     Document document;
     try {
       document = createDocument(stream);
     } catch (SAXException e) {
       throw new RuntimeException("Invalid properties format", e);
     }
     Element propertiesElement = (Element) document.getChildNodes().item(
         document.getChildNodes().getLength() - 1);
     importProperties(properties, propertiesElement);
   }
 
   private static Document createDocument(final InputStream stream)
       throws SAXException, IOException {
     DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
     factory.setIgnoringElementContentWhitespace(true);
     factory.setValidating(false);
     factory.setCoalescing(true);
     factory.setIgnoringComments(true);
     try {
       DocumentBuilder builder = factory.newDocumentBuilder();
       builder.setEntityResolver(new Resolver());
       InputSource source = new InputSource(stream);
       return builder.parse(source);
     } catch (ParserConfigurationException e) {
       throw new Error(e);
     }
   }
 
   static void importProperties(final Properties properties, final Element propertiesElement) {
     NodeList entries = propertiesElement.getChildNodes();
     int numEntries = entries.getLength();
     int start = numEntries > 0
         && entries.item(0).getNodeName().equals("comment") ? 1 : 0;
     for (int i = start; i < numEntries; i++) {
       Node child = entries.item(i);
       if (child instanceof Element) {
         Element entry = (Element) child;
         if (entry.hasAttribute("key")) {
           Node node = entry.getFirstChild();
           String value = (node == null) ? "" : node.getNodeValue();
           properties.setProperty(entry.getAttribute("key"), value);
         }
       }
     }
   }
 
   private static class Resolver implements EntityResolver {
 
     public InputSource resolveEntity(final String publicId, final String systemId)
         throws SAXException {
       String dtd = "<!ELEMENT properties (comment?, entry*)>"
           + "<!ATTLIST properties version CDATA #FIXED '1.0'>"
           + "<!ELEMENT comment (#PCDATA)>"
           + "<!ELEMENT entry (#PCDATA)>"
           + "<!ATTLIST entry key CDATA #REQUIRED>";
       InputSource inputSource = new InputSource(new StringReader(dtd));
       inputSource.setSystemId("http://java.sun.com/dtd/properties.dtd");
       return inputSource;
     }
   }
 
 }