/*
    * 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.assertj.core.api.Assertions.assertThat;
  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.lang.reflect.UndeclaredThrowableException;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  
  import java.util.Map;
  import javax.xml.namespace.QName;
  import javax.xml.parsers.ParserConfigurationException;
  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.XPathExpression;
  import javax.xml.xpath.XPathExpressionException;
  
  import org.apache.commons.xml.secure.SecureSAXParserFactory;
  import org.apache.commons.xml.secure.SecureTransformerFactory;
  import org.apache.rat.report.xml.writer.XmlWriter;
  import org.apache.rat.utils.DefaultLog;
  import org.apache.rat.utils.StandardXmlFactory;
  import org.opentest4j.AssertionFailedError;
  import org.w3c.dom.Document;
  import org.w3c.dom.NamedNodeMap;
  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;
  
  /**
   * Utilities to help test XML documents.
   */
  public final class XmlUtils {
      /**
       * Private constructor, to prevent accidental instantiation.
       */
      private XmlUtils() {
          // Does nothing
      }
  
      /**
       * Construct a safe XML reader.
       * @return an XML reader.
       * @throws SAXException on SAX exception.
       * @throws ParserConfigurationException on parser configuration exception.
       */
      public static XMLReader newXMLReader() throws SAXException, ParserConfigurationException {
          return SecureSAXParserFactory.newNSInstance().newSAXParser().getXMLReader();
      }
  
      /**
       * Determines whether the document string is well-formed.
       * @param string the document string to check.
       * @return {@code true} if the document is well-formed, {@code false} otherwise.
       */
      public static boolean isWellFormedXml(final String string) {
          return isWellFormedXml(new InputSource(new StringReader(string)));
      }
  
      /**
       * Determines whether the document in the input stream is well-formed.
       * @param in the input stream containing the document.
       * @return {@code true} if the document is well-formed, {@code false} otherwise.
       */
      public static boolean isWellFormedXml(final InputStream in) {
         return isWellFormedXml(new InputSource(in));
     }
 
     /**
      * Determines whether the document in the input source is well-formed.
      * @param isource the input source containing the document.
      * @return {@code true} if the document is well-formed, {@code false} otherwise.
      */
     public static boolean isWellFormedXml(final InputSource isource) {
         try {
             newXMLReader().parse(isource);
             return true;
         } catch (SAXException e) {
             DefaultLog.getInstance().error(e.getMessage(), e);
             return false;
         } catch (IOException | ParserConfigurationException e) {
             throw new UndeclaredThrowableException(e);
         }
     }
 
     /**
      * Gets a Nodelist from an XPath string.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath the XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      * @return the NodeList of nodes that matches the XPath.
      * @throws XPathExpressionException on error.
      */
     public static NodeList getNodeList(Object source, XPath xPath, String xpath) throws XPathExpressionException {
         return (NodeList) xPath.compile(xpath).evaluate(source, XPathConstants.NODESET);
     }
 
     /**
      * Determines whether an XPath identified a node in the source.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath the XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      * @return {@code true} if the document contains the node identified by the XPath statement, {@code false} otherwise.
      * @throws XPathExpressionException on error.
      */
     public static boolean isPresent(Object source, XPath xPath, String xpath) throws XPathExpressionException {
         Object node = xPath.compile(xpath).evaluate(source, XPathConstants.NODE);
         return node != null;
     }
 
     /**
      * Gets a List of Nodes from an XPath string.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath the XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      * @return the list of nodes that match the XPath.
      * @throws XPathExpressionException on error.
      */
     public static List<Node> getNodes(Object source, XPath xPath, String xpath) throws XPathExpressionException {
         NodeList nodeList = (NodeList) xPath.compile(xpath).evaluate(source, XPathConstants.NODESET);
         List<Node> result = new ArrayList<>();
         for (int i = 0; i < nodeList.getLength(); i++) {
             result.add(nodeList.item(i));
         }
         return result;
     }
 
     /**
      * Gets a node identified by an XPath.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath the XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      * @return the identified Node.
      * @throws XPathExpressionException on error.
      * @throws AssertionFailedError if more than one node is found.
      */
     public static Node getNode(Object source, XPath xPath, String xpath) throws XPathExpressionException {
         NodeList nodeList = getNodeList(source, xPath, xpath);
         assertEquals(1, nodeList.getLength(), "Could not find exactly one " + xpath);
         return nodeList.item(0);
     }
 
     /**
      * Prints the specified NodeList as a string representation of its contents.
      * @param nodeList the Nodelist to print.
      * @return the string that contains the textual representation of the NodeList nodes.
      */
     public static String printNodeList(NodeList nodeList) {
         StringBuilder sb = new StringBuilder();
         for (int i = 0; i < nodeList.getLength(); i++) {
             Node n = nodeList.item(0);
             sb.append(n.getNodeName()).append(" ");
             NamedNodeMap nnm = n.getAttributes();
             for (int j = 0; j < nnm.getLength(); j++) {
                 Node a = nnm.item(j);
                 sb.append(a.getNodeName()).append("=").append(a.getNodeValue()).append(" ");
             }
             sb.append("\n");
         }
         return sb.toString();
     }
 
     /**
      * Reads an input stream into a document.
      * @param inputStream the input stream to read.
      * @return the Document.
      * @throws SAXException on sax Error
      * @throws IOException on IO Error
      */
     public static Document toDom(final InputStream inputStream)
             throws SAXException, IOException {
         return StandardXmlFactory.documentBuilder().parse(inputStream);
     }
 
     /**
      * Writes a boolean attribute to an XML writer.
      * @param writer the writer to write to.
      * @param name the name of the attribute.
      * @param booleanValue the boolean value.
      * @throws IOException on write error.
      */
     public static void writeAttribute(final XmlWriter writer, final String name, final boolean booleanValue)
             throws IOException {
         final String value = Boolean.toString(booleanValue);
         writer.attribute(name, value);
     }
 
     /**
      * Print the 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 = SecureTransformerFactory.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, StandardCharsets.UTF_8)));
         } catch (TransformerException e) {
             e.printStackTrace(new PrintStream(out));
         }
     }
 
     /**
      * Get an attribute from an XPath statement
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath the XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      * @param attribute attribute to retrieve from the node specified by the XPath statement.
      * @return the string value of the attribute.
      * @throws XPathExpressionException on error
      */
     public static String getAttribute(Object source, XPath xPath, String xpath, String attribute) throws XPathExpressionException {
         Node node = XmlUtils.getNode(source, xPath, xpath);
         NamedNodeMap attr = node.getAttributes();
         node = attr.getNamedItem(attribute);
         assertThat(node).as(attribute + " was not found").isNotNull();
         return node.getNodeValue();
     }
 
     public static Map<String, String> mapOf(String... parts) {
         Map<String, String> map = new HashMap<>();
         for (int i = 0; i < parts.length; i += 2) {
             map.put(parts[i], parts[i+1]);
         }
         return map;
     }
 
     /**
      * Assert that attributes are set on a node.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath the XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      * @param attributes a map of attribute names to values.
      * @throws XPathExpressionException on error.
      */
     public static void assertAttributes(Object source, XPath xPath, String xpath, Map<String, String> attributes) throws XPathExpressionException {
         Node node = XmlUtils.getNode(source, xPath, xpath);
         NamedNodeMap attr = node.getAttributes();
         for (Map.Entry<String, String> entry : attributes.entrySet()) {
             node = attr.getNamedItem(entry.getKey());
             assertThat(node).as(() -> entry.getKey() + " was not found on " + xpath).isNotNull();
             assertThat(node.getNodeValue()).as(() -> entry.getKey() + " on " + xpath).isEqualTo(entry.getValue());
         }
     }
 
     /**
      * Assert that an XPath is present in the document.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath the XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
     */
     public static void assertIsPresent(Object source, XPath xPath, String xpath) throws XPathExpressionException {
         assertThat(isPresent(source, xPath, xpath)).as("Presence of " + xpath).isTrue();
     }
 
     /**
      * Assert that an XPath is not present in the document.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath the XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      */
     public static void assertIsNotPresent(Object source, XPath xPath, String xpath) throws XPathExpressionException {
         assertThat(isPresent(source, xPath, xpath)).as("Non-presence of " + xpath).isFalse();
     }
 
     /**
      * Assert that a named XPath is present in the document.
      * @param identifier the name of the object.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath The XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      */
     public static void assertIsPresent(String identifier, Object source, XPath xPath, String xpath) throws XPathExpressionException {
         assertThat(isPresent(source, xPath, xpath)).as(identifier + ": Presence of " + xpath).isTrue();
     }
 
     /**
      * Assert that a named XPath is not present in the document.
      * @param identifier the name of the object.
      * @param source the context for the XPath statement to be evaluated in. See {@link XPathExpression#evaluate(Object, QName)}.
      * @param xPath The XPath object to compile the statement with.
      * @param xpath the XPath statement to compile.
      */
     public static void assertIsNotPresent(String identifier, Object source, XPath xPath, String xpath) throws XPathExpressionException {
         assertThat(isPresent(source, xPath, xpath)).as(identifier + ": Non-presence of " + xpath).isFalse();
     }
 }