/*
    * Copyright 2012 smartics, Kronseder & Reiner GmbH
    *
    * Licensed 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 de.smartics.ci.config.hudson;
  
  import static de.smartics.ci.config.utils.JDomUtils.calcXPath;
  
  import org.jdom.Element;
  import org.jdom.JDOMException;
  import org.jdom.Text;
  import org.jdom.xpath.XPath;
  
  /**
   * Definition of XML elements of a Hudson configuration.
   */
  public enum HudsonConfigElement
  {
    // ****************************** Enumeration *******************************
  
    /**
     * Identifies the <code>entry</code> XML element.
     */
    ENTRY("entry")
    {
      @Override
      public Element findElementWithin(final Element rootElement,
          final Element element, final Element targetRootElement)
        throws JDOMException
      {
        final XPath xpath = XPath.newInstance("string/text()");
        final Text entryIdText = (Text) xpath.selectSingleNode(element);
        if (entryIdText == null)
        {
          return null;
        }
  
        final String id = entryIdText.getTextTrim();
        final String xPathString =
            "/maven2-moduleset/project-properties/entry/string[text()='" + id
                + "']";
        final XPath xPath = XPath.newInstance(xPathString);
        final Object object = xPath.selectSingleNode(targetRootElement);
        if (object != null)
        {
          final Element parent = ((Element) object).getParentElement();
          return parent;
        }
        return null;
      }
    };
  
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The name of the XML element this enum element identifies.
     */
    private final String name;
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     *
     * @param name the name of the XML element this enum element identifies.
     */
    private HudsonConfigElement(final String name)
    {
      this.name = name;
    }
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    // --- get&set --------------------------------------------------------------
  
    /**
     * Returns the name of the XML element this enum element identifies.
     *
     * @return the name of the XML element this enum element identifies.
     */
    public String getName()
    {
     return name;
   }
 
   // --- business -------------------------------------------------------------
 
   /**
    * Returns the element for the given name.
    *
    * @param elementName the name of the request element.
    * @return the requested element.
    * @throws IllegalArgumentException if the {@code elementName} does not match
    *           a known element name.
    */
   public static HudsonConfigElement valueFor(final String elementName)
     throws IllegalArgumentException
   {
     for (final HudsonConfigElement element : values())
     {
       if (element.name.equals(elementName))
       {
         return element;
       }
     }
 
     throw new IllegalArgumentException("Cannot find element for name '"
                                        + elementName + "'.");
   }
 
   /**
    * Finds the element within the target root element.
    * <p>
    * {@code rootElement} is analog to {@code targetRootElement}. This method
    * finds the analog element of {@code element} within the target document.
    * </p>
    *
    * @param rootElement the root element to the element.
    * @param element the element relative to the {@code rootElement}.
    * @param targetRootElement the root element within which the element
    *          specified by {@code element} is requested. This root element is
    *          the root element of the target document.
    * @return the analog element of {@code element} within
    *         {@code targetRootElement}.
    * @throws JDOMException on any problem accessing any element information.
    */
   public static Element findElement(final Element rootElement,
       final Element element, final Element targetRootElement)
     throws JDOMException
   {
     final String elementName = element.getName();
     try
     {
       final HudsonConfigElement config = valueFor(elementName);
       return config.findElementWithin(rootElement, element, targetRootElement);
     }
     catch (final IllegalArgumentException e)
     {
       return defaultFindElement(rootElement, element, targetRootElement);
     }
   }
 
   private static Element defaultFindElement(final Element rootElement,
       final Element element, final Element targetRootElement)
     throws JDOMException
   {
     final String path = calcXPath(rootElement, element);
     final XPath xPath = XPath.newInstance(path);
     final Object object = xPath.selectSingleNode(targetRootElement);
     return (Element) object;
   }
 
   abstract Element findElementWithin(final Element rootElement,
       final Element element, final Element targetRootElement)
     throws JDOMException;
 
   // --- object basics --------------------------------------------------------
 
 }