/*
    * 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.rat.testhelpers;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.PrintStream;
  import java.io.StringReader;
  import java.io.UnsupportedEncodingException;
  import java.lang.reflect.UndeclaredThrowableException;
  
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.parsers.FactoryConfigurationError;
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.parsers.SAXParserFactory;
  import javax.xml.transform.OutputKeys;
  import javax.xml.transform.Transformer;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.TransformerFactory;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.transform.stream.StreamResult;
  import javax.xml.xpath.XPath;
  import javax.xml.xpath.XPathConstants;
  import javax.xml.xpath.XPathExpressionException;
  
  import org.apache.rat.license.ILicenseFamily;
  import org.apache.rat.report.xml.writer.IXmlWriter;
  import org.w3c.dom.Document;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  import org.xml.sax.XMLReader;
  
  public final class XmlUtils {
      /**
       * Private constructor, to prevent accidental instantiation.
       */
      private XmlUtils() {
          // Does nothing
      }
  
      public static final boolean isWellFormedXml(final String string) throws Exception {
          return isWellFormedXml(new InputSource(new StringReader(string)));
      }
  
      public static final XMLReader newXMLReader() throws SAXException, ParserConfigurationException {
          final SAXParserFactory spf = SAXParserFactory.newInstance();
          spf.setValidating(false);
          spf.setNamespaceAware(true);
          return spf.newSAXParser().getXMLReader();
      }
  
      public static final boolean isWellFormedXml(final InputSource isource) {
          try {
              newXMLReader().parse(isource);
              return true;
          } catch (SAXException e) {
              e.printStackTrace();
              return false;
          } catch (IOException | ParserConfigurationException e) {
              throw new UndeclaredThrowableException(e);
          }
      }
  
      /**
       * Finds a node via xpath on the document. And then checks family, approval and
       * type of elements of the node.
       * 
       * @param doc The document to check/
       * @param xpath the XPath instance to use.
       * @param resource the xpath statement to locate the node.
       * @param family the expected family for the node (may be null)
       * @param approval the expected approval value (may be null)
       * @param type the type of resource located.
       * @return The node that was located
       * @throws Exception on XPath error.
       */
     public static Node checkNode(Document doc, XPath xpath, String resource, String family, String approval,
             String type) throws Exception {
         Node root = getNode(doc, xpath, String.format("/rat-report/resource[@name='%s']", resource));
         if (family != null) {
             getNode(root, xpath, String.format("header-type[@name='%s']", ILicenseFamily.makeCategory(family)));
             getNode(root, xpath, "license-family[@name]");
             if (family.equals("?????")) {
                 getNode(root, xpath, "header-sample");
             }
         }
         if (approval != null) {
             getNode(root, xpath, String.format("license-approval[@name='%s']", approval));
         }
         getNode(root, xpath, String.format("type[@name='%s']", type));
         return root;
     }
 
     public static Node getNode(Object source, XPath xPath, String xpath) throws XPathExpressionException {
         NodeList nodeList = (NodeList) xPath.compile(xpath).evaluate(source, XPathConstants.NODESET);
         assertEquals(1, nodeList.getLength(), "Could not find " + xpath);
         return nodeList.item(0);
     }
 
     public static final boolean isWellFormedXml(final InputStream in) throws Exception {
         return isWellFormedXml(new InputSource(in));
     }
 
     public static final Document toDom(final InputStream in)
             throws SAXException, IOException, ParserConfigurationException, FactoryConfigurationError {
         final DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
         Document result;
         result = builder.parse(in);
         return result;
     }
 
     public static final void writeAttribute(final IXmlWriter writer, final String name, final boolean booleanValue)
             throws IOException {
         final String value = Boolean.toString(booleanValue);
         writer.attribute(name, value);
     }
 
     /**
      * Print the and XML document to the output stream
      * 
      * @param out the OutputStream to print the document to.
      * @param document The XML DOM document to print
      */
     public static void printDocument(OutputStream out, Document document) {
         TransformerFactory tf = TransformerFactory.newInstance();
         Transformer transformer;
         try {
             transformer = tf.newTransformer();
 
             transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
             transformer.setOutputProperty(OutputKeys.METHOD, "xml");
             transformer.setOutputProperty(OutputKeys.INDENT, "yes");
             transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
             transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
 
             transformer.transform(new DOMSource(document), new StreamResult(new OutputStreamWriter(out, "UTF-8")));
         } catch (TransformerException | UnsupportedEncodingException e) {
             e.printStackTrace(new PrintStream(out));
         }
     }
 
 }