package us.codecraft.webmagic.selector;
   
   import org.jsoup.nodes.Document;
   import org.jsoup.nodes.Element;
   
   import java.util.ArrayList;
   import java.util.List;
   import java.util.ListIterator;
   
  /**
   * @author code4crafer@gmail.com
   */
  public class HtmlNode extends AbstractSelectable {
  
      private final List<Element> elements;
  
      public HtmlNode(List<Element> elements) {
          this.elements = elements;
      }
  
      public HtmlNode() {
          elements = null;
      }
  
      protected List<Element> getElements() {
          return elements;
      }
  
      public Selectable smartContent() {
          SmartContentSelector smartContentSelector = Selectors.smartContent();
          return select(smartContentSelector, getSourceTexts());
      }
  
      @Override
      public Selectable links() {
          return selectElements(new LinksSelector());
      }
  
      @Override
      public Selectable xpath(String xpath) {
          XpathSelector xpathSelector = Selectors.xpath(xpath);
          return selectElements(xpathSelector);
      }
  
      @Override
      public Selectable selectList(Selector selector) {
          if (selector instanceof BaseElementSelector) {
             return selectElements((BaseElementSelector) selector);
          }
          return selectList(selector, getSourceTexts());
      }
  
      @Override
      public Selectable select(Selector selector) {
          return selectList(selector);
      }
  
      /**
       * select elements
       *
       * @param elementSelector elementSelector
       * @return result
       */
      protected Selectable selectElements(BaseElementSelector elementSelector) {
          ListIterator<Element> elementIterator = getElements().listIterator();
          if (!elementSelector.hasAttribute()) {
              List<Element> resultElements = new ArrayList<Element>();
              while (elementIterator.hasNext()) {
                  Element element = checkElementAndConvert(elementIterator);
                  List<Element> selectElements = elementSelector.selectElements(element);
                  resultElements.addAll(selectElements);
              }
              return new HtmlNode(resultElements);
          } else {
              // has attribute, consider as plaintext
              List<String> resultStrings = new ArrayList<String>();
              while (elementIterator.hasNext()) {
                  Element element = checkElementAndConvert(elementIterator);
                  List<String> selectList = elementSelector.selectList(element);
                  resultStrings.addAll(selectList);
              }
              return new PlainText(resultStrings);
  
          }
      }
  
      /**
       * Only document can be select
       * See: https://github.com/code4craft/webmagic/issues/113
       *
       * @param elementIterator elementIterator
       * @return element element
       */
      private Element checkElementAndConvert(ListIterator<Element> elementIterator) {
          Element element = elementIterator.next();
          if (!(element instanceof Document)) {
              Document root = new Document(element.ownerDocument().baseUri());
              Element clone = element.clone();
              root.appendChild(clone);
             elementIterator.set(root);
             return root;
         }
         return element;
     }
 
     @Override
     public Selectable $(String selector) {
         CssSelector cssSelector = Selectors.$(selector);
         return selectElements(cssSelector);
     }
 
     @Override
     public Selectable $(String selector, String attrName) {
         CssSelector cssSelector = Selectors.$(selector, attrName);
         return selectElements(cssSelector);
     }
 
     @Override
     public List<Selectable> nodes() {
         List<Selectable> selectables = new ArrayList<Selectable>();
         for (Element element : getElements()) {
             List<Element> childElements = new ArrayList<Element>(1);
             childElements.add(element);
             selectables.add(new HtmlNode(childElements));
         }
         return selectables;
     }
 
     @Override
     protected List<String> getSourceTexts() {
         List<String> sourceTexts = new ArrayList<String>(getElements().size());
         for (Element element : getElements()) {
             sourceTexts.add(element.toString());
         }
         return sourceTexts;
     }
 }