package org.rundeck.api.parser;
   
   import org.apache.commons.lang.StringUtils;
   import org.dom4j.Node;
   
   /**
    * BaseXpathParser is ...
    *
    * @author Greg Schueler <greg@simplifyops.com>
   * @since 2014-04-04
   */
  public abstract class BaseXpathParser<T> implements XmlNodeParser<T> {
      private String xpath;
  
      public BaseXpathParser() {
      }
  
      public BaseXpathParser(String xpath) {
  
          this.xpath = xpath;
      }
  
      public abstract T parse(Node node);
  
      @Override
      public final T parseXmlNode(Node node) {
          return parse(selectNode(node));
      }
  
      /**
       * Select appropriate node based on xpath, will automatically look for "result" top-level element and alter xpath if
       * necessary
       *
       * @param node
       *
       * @return
       */
      private Node selectNode(final Node node) {
          return selectNodeAndUnwrap(node, xpath);
      }
  
      /**
       * Select appropriate node based on xpath, will automatically look for "result" top-level element and alter xpath if
       * necessary
       * @param node
       * @param xpath
       * @return
       */
      public static Node selectNodeAndUnwrap(final Node node, final String xpath) {
          String useXpath = unwrapXpath(node, xpath);
  
          if (StringUtils.isNotEmpty(useXpath)) {
              return node.selectSingleNode(useXpath);
          } else {
              return node;
          }
      }
  
      /**
       * @param node
       * @param xpath
       * @return appropriate xpath to use based on whether node has a 'result' root element
       */
      public static String unwrapXpath(final Node node, final String xpath) {
          boolean rootResult = node.getName() == null && "result".equals(node.getDocument().getRootElement().getName());
          boolean isEmpty = StringUtils.isEmpty(xpath);
          String useXpath = xpath;
          if (isEmpty) {
              if (rootResult) {
                  useXpath = "result/*";
              }
          } else if (rootResult) {
              if (!useXpath.startsWith("result") &&!useXpath.startsWith("/result") && !useXpath.startsWith("//")) {
                  useXpath = "result/" + xpath;
              }
          } else if (useXpath.startsWith("result") ) {
              //starts with result/... but no result element
              useXpath = xpath.substring("result".length());
          }else if (useXpath.startsWith("/result")) {
              //starts with /result/... but no result element
              useXpath = xpath.substring("/result".length());
          }
          return useXpath;
      }
  }