/*
 * 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.activemq.artemis.utils;

import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.List;

import org.apache.activemq.artemis.core.client.ActiveMQClientLogger;
import org.apache.activemq.artemis.core.client.ActiveMQClientMessageBundle;
import org.jboss.logging.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
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;

public final class XMLUtil {

   private static final Logger logger = Logger.getLogger(XMLUtil.class);

   private XMLUtil() {
      // Utility class
   }

   public static String CONSIDER_OS_ENV_PROP = "org.apache.activemq.artemis.utils.considerOsEnv";
   private static final boolean considerOsEnv;
   static {
      considerOsEnv = Boolean.parseBoolean(System.getProperty(CONSIDER_OS_ENV_PROP, "true"));
   }

   public static Element streamToElement(InputStream inputStream) throws Exception {
      try (Reader reader = new InputStreamReader(inputStream)) {
         return XMLUtil.readerToElement(reader);
      }
   }

   public static Element stringToElement(final String s) throws Exception {
      return XMLUtil.readerToElement(new StringReader(s));
   }

   public static Element urlToElement(final URL url) throws Exception {
      return XMLUtil.streamToElement(url.openStream());
   }

   public static String readerToString(final Reader r) throws Exception {
      // Read into string
      StringBuilder buff = new StringBuilder();
      int c;
      while ((c = r.read()) != -1) {
         buff.append((char) c);
      }
      return buff.toString();
   }

   public static Element readerToElement(final Reader r) throws Exception {
      DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
      factory.setNamespaceAware(true);
      factory.setXIncludeAware(true);
      DocumentBuilder parser = factory.newDocumentBuilder();
      Document doc = replaceSystemPropsInXml(parser.parse(new InputSource(new StringReader(replaceSystemPropsInString(readerToString(r))))));
      return doc.getDocumentElement();
   }

   public static String elementToString(final Node n) {

      String name = n.getNodeName();

      short type = n.getNodeType();

      if (Node.CDATA_SECTION_NODE == type) {
         return "<![CDATA[" + n.getNodeValue() + "]]>";
      }

      if (name.startsWith("#")) {
         return "";
      }

      StringBuffer sb = new StringBuffer();
      sb.append('<').append(name);

      NamedNodeMap attrs = n.getAttributes();
      if (attrs != null) {
         for (int i = 0; i < attrs.getLength(); i++) {
            Node attr = attrs.item(i);
            sb.append(' ').append(attr.getNodeName()).append("=\"").append(attr.getNodeValue()).append("\"");
         }
      }

      String textContent;
      NodeList children = n.getChildNodes();

      if (children.getLength() == 0) {
         if ((textContent = XMLUtil.getTextContent(n)) != null && !"".equals(textContent)) {
            sb.append(textContent).append("</").append(name).append('>');
         } else {
            sb.append("/>").append('\n');
         }
      } else {
         sb.append('>').append('\n');
         boolean hasValidChildren = false;
         for (int i = 0; i < children.getLength(); i++) {
            String childToString = XMLUtil.elementToString(children.item(i));
            if (!"".equals(childToString)) {
               sb.append(childToString);
               hasValidChildren = true;
            }
         }

         if (!hasValidChildren && (textContent = XMLUtil.getTextContent(n)) != null) {
            sb.append(textContent);
         }

         sb.append("</").append(name).append('>');
      }

      return sb.toString();
   }

   /**
    * Note: if the content is another element or set of elements, it returns a string representation
    * of the hierarchy.
    */
   public static String getTextContent(final Node n) {
      if (n.hasChildNodes()) {
         StringBuffer sb = new StringBuffer();
         NodeList nl = n.getChildNodes();
         for (int i = 0; i < nl.getLength(); i++) {
            sb.append(XMLUtil.elementToString(nl.item(i)));
            if (i < nl.getLength() - 1) {
               sb.append('\n');
            }
         }

         String s = sb.toString();
         if (s.length() != 0) {
            return s;
         }
      }

      return n.getTextContent();
   }

   public static void assertEquivalent(final Node node, final Node node2) {
      if (node == null) {
         throw ActiveMQClientMessageBundle.BUNDLE.firstNodeNull();
      }

      if (node2 == null) {
         throw ActiveMQClientMessageBundle.BUNDLE.secondNodeNull();
      }

      if (!node.getNodeName().equals(node2.getNodeName())) {
         throw ActiveMQClientMessageBundle.BUNDLE.nodeHaveDifferentNames();
      }

      int attrCount = 0;
      NamedNodeMap attrs = node.getAttributes();
      if (attrs != null) {
         attrCount = attrs.getLength();
      }

      int attrCount2 = 0;
      NamedNodeMap attrs2 = node2.getAttributes();
      if (attrs2 != null) {
         attrCount2 = attrs2.getLength();
      }

      if (attrCount != attrCount2) {
         throw ActiveMQClientMessageBundle.BUNDLE.nodeHaveDifferentAttNumber();
      }

   outer:
      for (int i = 0; i < attrCount; i++) {
         Node n = attrs.item(i);
         String name = n.getNodeName();
         String value = n.getNodeValue();

         for (int j = 0; j < attrCount; j++) {
            Node n2 = attrs2.item(j);
            String name2 = n2.getNodeName();
            String value2 = n2.getNodeValue();

            if (name.equals(name2) && value.equals(value2)) {
               continue outer;
            }
         }
         throw ActiveMQClientMessageBundle.BUNDLE.attsDontMatch(name, value);
      }

      boolean hasChildren = node.hasChildNodes();

      if (hasChildren != node2.hasChildNodes()) {
         throw ActiveMQClientMessageBundle.BUNDLE.oneNodeHasChildren();
      }

      if (hasChildren) {
         NodeList nl = node.getChildNodes();
         NodeList nl2 = node2.getChildNodes();

         short[] toFilter = new short[]{Node.TEXT_NODE, Node.ATTRIBUTE_NODE, Node.COMMENT_NODE};
         List<Node> nodes = XMLUtil.filter(nl, toFilter);
         List<Node> nodes2 = XMLUtil.filter(nl2, toFilter);

         int length = nodes.size();

         if (length != nodes2.size()) {
            throw ActiveMQClientMessageBundle.BUNDLE.nodeHasDifferentChildNumber();
         }

         for (int i = 0; i < length; i++) {
            Node n = nodes.get(i);
            Node n2 = nodes2.get(i);
            XMLUtil.assertEquivalent(n, n2);
         }
      }
   }

   public static String stripCDATA(String s) {
      s = s.trim();
      if (s.startsWith("<![CDATA[")) {
         s = s.substring(9);
         int i = s.indexOf("]]>");
         if (i == -1) {
            throw new IllegalStateException("argument starts with <![CDATA[ but cannot find pairing ]]>");
         }
         s = s.substring(0, i);
      }
      return s;
   }

   public static String replaceSystemPropsInString(String xml) {
      while (xml.contains("${")) {
         int start = xml.indexOf("${");
         int end = xml.indexOf("}", start) + 1;

         if (start < 0 || end <= 0) {
            break;
         }

         String subString = xml.substring(start, end);
         String prop = subString.substring(2, subString.length() - 1).trim();
         String val = "";

         if (prop.contains(":")) {
            String[] parts = prop.split(":", 2);
            prop = parts[0].trim();
            val = parts[1].trim();
         }

         String sysProp = System.getProperty(prop);
         if (sysProp == null && considerOsEnv) {
            sysProp = System.getenv(prop);
         }
         if (sysProp == null) {
            sysProp = val;
         }
         // interesting choice to replace with val == "" with no match!
         logger.debug("replacing " + subString + " with " + sysProp);
         xml = xml.replace(subString, sysProp);
      }

      return xml;
   }

   public static Document replaceSystemPropsInXml(Document doc) {
      NodeList nodeList = doc.getElementsByTagName("*");
      for (int i = 0, len = nodeList.getLength(); i < len; i++) {
         Node node = nodeList.item(i);
         if (node != null && node.getNodeType() == Node.ELEMENT_NODE) {
            if (node.hasAttributes()) {
               NamedNodeMap attributes = node.getAttributes();
               for (int j = 0; j < attributes.getLength(); j++) {
                  Node attribute = attributes.item(j);
                  attribute.setTextContent(XMLUtil.replaceSystemPropsInString(attribute.getTextContent()));
               }
            }
            if (node.hasChildNodes()) {
               NodeList children = node.getChildNodes();
               for (int j = 0; j < children.getLength(); j++) {
                  String value = children.item(j).getNodeValue();
                  if (value != null) {
                     children.item(j).setNodeValue(XMLUtil.replaceSystemPropsInString(value));
                  }
               }
            }
         }
      }

      return doc;
   }

   public static long parseLong(final Node elem) {
      String value = elem.getTextContent().trim();

      try {
         return Long.parseLong(value);
      } catch (NumberFormatException e) {
         throw ActiveMQClientMessageBundle.BUNDLE.mustBeLong(elem, value);
      }
   }

   public static int parseInt(final Node elem) {
      String value = elem.getTextContent().trim();

      return parseInt(elem, value);
   }

   public static int parseInt(Node elem, String value) {
      try {
         return Integer.parseInt(value);
      } catch (NumberFormatException e) {
         throw ActiveMQClientMessageBundle.BUNDLE.mustBeInteger(elem, value);
      }
   }

   public static boolean parseBoolean(final Node elem) {
      String value = elem.getTextContent().trim();

      try {
         return Boolean.parseBoolean(value);
      } catch (NumberFormatException e) {
         throw ActiveMQClientMessageBundle.BUNDLE.mustBeBoolean(elem, value);
      }
   }

   public static double parseDouble(final Node elem) {
      String value = elem.getTextContent().trim();

      try {
         return Double.parseDouble(value);
      } catch (NumberFormatException e) {
         throw ActiveMQClientMessageBundle.BUNDLE.mustBeDouble(elem, value);
      }
   }

   public static void validate(final Node node, final String schemaFile) throws Exception {
      SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);

      Schema schema = factory.newSchema(new URL(findResource(schemaFile).toURI().toASCIIString()));
      Validator validator = schema.newValidator();

      // validate the DOM tree
      try {
         validator.validate(new DOMSource(node));
      } catch (SAXException e) {
         ActiveMQClientLogger.LOGGER.errorOnXMLTransformInvalidConf(e);

         throw new IllegalStateException("Invalid configuration", e);
      }
   }

   private static List<Node> filter(final NodeList nl, final short[] typesToFilter) {
      List<Node> nodes = new ArrayList<>();

   outer:
      for (int i = 0; i < nl.getLength(); i++) {
         Node n = nl.item(i);
         short type = n.getNodeType();
         for (short typeToFilter : typesToFilter) {
            if (typeToFilter == type) {
               continue outer;
            }
         }
         nodes.add(n);
      }
      return nodes;
   }

   public static URL findResource(final String resourceName) {
      return AccessController.doPrivileged(new PrivilegedAction<URL>() {
         @Override
         public URL run() {
            return ClassloadingUtil.findResource(resourceName);
         }
      });
   }

}
