/*
    * Copyright 2012 DTO Labs, Inc. (http://dtolabs.com)
    * 
    * 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.
   *
   */
  
  /*
  * PagedResultParser.java
  * 
  * User: Greg Schueler <a href="mailto:greg@dtosolutions.com">greg@dtosolutions.com</a>
  * Created: 9/28/12 10:37 AM
  * 
  */
  package org.rundeck.api.parser;
  
  import org.dom4j.Element;
  import org.dom4j.Node;
  import org.rundeck.api.RundeckApiException;
  import org.rundeck.api.util.PagedResults;
  
  import java.util.*;
  
  
  /**
   * PagedResultParser extracts paging data from an xpath node, and includes the List result from a ListParser
   *
   * @author Greg Schueler <a href="mailto:greg@dtosolutions.com">greg@dtosolutions.com</a>
   */
  public class PagedResultParser<T> implements XmlNodeParser<PagedResults<T>> {
      ListParser<T> itemParser;
      private String xpath;
  
      /**
       * Create a PagedResultParser
       *
       * @param itemParser the list parser
       * @param xpath      xpath for list container containing paging attributes
       */
      public PagedResultParser(ListParser<T> itemParser, String xpath) {
          this.itemParser = itemParser;
          this.xpath = xpath;
      }
  
      @Override
      public PagedResults<T> parseXmlNode(Node node) {
          Node pagedNodeContainer = BaseXpathParser.selectNodeAndUnwrap(node, xpath);
          if(null==pagedNodeContainer) {
              throw new RundeckApiException("XML content did not match XPATH expression: " + xpath);
          }
          Element el = (Element) pagedNodeContainer;
          final int max = integerAttribute(el, "max", -1);
          final int offset = integerAttribute(el, "offset", -1);
          final int total = integerAttribute(el, "total", -1);
          final int count = integerAttribute(el, "count", -1);
  
          final List<T> ts = itemParser.parseXmlNode(pagedNodeContainer);
  
  
          return new PagedResults<T>() {
              @Override
              public int getMax() {
                  return max;
              }
  
              @Override
              public int getOffset() {
                  return offset;
              }
  
              @Override
              public int getTotal() {
                  return total;
              }
  
              @Override
              public List<T> getResults() {
                  return ts;
              }
  
              @Override
              public int getCount() {
                  return count;
              }
  
              @Override
              public Iterator<T> iterator() {
                  return ts.iterator();
              }
         };
     }
 
     /**
      * Return an integer value of an attribute of an element, or a default value if it is not found or not an integer.
      *
      * @param el        the element
      * @param attribute attribute name
      * @param defValue  default value to return
      */
     private int integerAttribute(Element el, final String attribute, final int defValue) {
         int parseMax = defValue;
         try {
             final String max1 = null != el.attribute(attribute) ? el.attribute(attribute).getStringValue() : null;
             parseMax = null != max1 ? Integer.parseInt(max1) : defValue;
         } catch (NumberFormatException e) {
         }
         return parseMax;
     }
 
     public String getXpath() {
         return xpath;
     }
 }