<?php
  /**
   * DOMPDF - PHP5 HTML to PDF renderer
   *
   * File: $RCSfile: frame_tree.cls.php,v $
   * Created on: 2004-06-02
   *
   * Copyright (c) 2004 - Benj Carson <benjcarson@digitaljunkies.ca>
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public License
   * along with this library in the file LICENSE.LGPL; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   * 02111-1307 USA
   *
   * Alternatively, you may distribute this software under the terms of the
   * PHP License, version 3.0 or later.  A copy of this license should have
   * been distributed with this file in the file LICENSE.PHP .  If this is not
   * the case, you can obtain a copy at http://www.php.net/license/3_0.txt.
   *
   * The latest version of DOMPDF might be available at:
   * http://www.dompdf.com/
   *
   * @link http://www.dompdf.com/
   * @copyright 2004 Benj Carson
   * @author Benj Carson <benjcarson@digitaljunkies.ca>
   * @package dompdf
  
   */
  
  /* $Id: frame_tree.cls.php 332 2010-11-27 14:06:34Z fabien.menager $ */
  
  /**
   * Represents an entire document as a tree of frames
   *
   * The Frame_Tree consists of {@link Frame} objects each tied to specific
   * DomNode objects in a specific DomDocument.  The Frame_Tree has the same
   * structure as the DomDocument, but adds additional capabalities for
   * styling and layout.
   *
   * @package dompdf
   * @access protected
   */
  class Frame_Tree {
      
    /**
     * Tags to ignore while parsing the tree
     *
     * @var array
     */
    static protected $_HIDDEN_TAGS = array("area", "base", "basefont", "head", "style",
                                           "meta", "title", "colgroup",
                                           "noembed", "noscript", "param", "#comment");  
    /**
     * The main DomDocument
     *
     * @see http://ca2.php.net/manual/en/ref.dom.php
     * @var DomDocument
     */
    protected $_dom;
  
    /**
     * The root node of the FrameTree.
     *
     * @var Frame
     */
    protected $_root;
  
    /**
     * Subtrees of absolutely positioned elements
     *
     * @var array of Frames
     */
    protected $_absolute_frames;
  
    /**
     * A mapping of {@link Frame} objects to DomNode objects
     *
     * @var array
     */
    protected $_registry;
    
  
    /**
     * Class constructor
     *
     * @param DomDocument $dom the main DomDocument object representing the current html document
     */
    function __construct(DomDocument $dom) {
      $this->_dom = $dom;
      $this->_root = null;
      $this->_registry = array();
    }
    
    function __destruct() {
      clear_object($this);
    }
  
    /**
     * Returns the DomDocument object representing the curent html document
     *
     * @return DomDocument
     */
    function get_dom() { return $this->_dom; }
  
    /**
     * Returns the root frame of the tree
     *
     * @return Frame
     */
    function get_root() { return $this->_root; }
  
    /**
     * Returns a specific frame given its id
     *
     * @param string $id
     * @return Frame
     */
    function get_frame($id) { return isset($this->_registry[$id]) ? $this->_registry[$id] : null; }
  
    /**
     * Returns a post-order iterator for all frames in the tree
     *
     * @return FrameTreeList
     */
    function get_frames() { return new FrameTreeList($this->_root); }
        
    /**
     * Builds the tree
     */
    function build_tree() {
      $html = $this->_dom->getElementsByTagName("html")->item(0);
      if ( is_null($html) )
        $html = $this->_dom->firstChild;
  
      if ( is_null($html) )
        throw new DOMPDF_Exception("Requested HTML document contains no data.");
  
      $this->_root = $this->_build_tree_r($html);
  
    }
  
    /**
     * Recursively adds {@link Frame} objects to the tree
     *
     * Recursively build a tree of Frame objects based on a dom tree.
     * No layout information is calculated at this time, although the
     * tree may be adjusted (i.e. nodes and frames for generated content
     * and images may be created).
     *
     * @param DomNode $node the current DomNode being considered
     * @return Frame
     */
    protected function _build_tree_r(DomNode $node) {
      
      $frame = new Frame($node);
      $id = $frame->get_id();
      $this->_registry[ $id ] = $frame;
      
      if ( !$node->hasChildNodes() )
        return $frame;
  
      // Fixes 'cannot access undefined property for object with
      // overloaded access', fix by Stefan radulian
      // <stefan.radulian@symbion.at>    
      //foreach ($node->childNodes as $child) {
  
      // Store the children in an array so that the tree can be modified
      $children = array();
      for ($i = 0; $i < $node->childNodes->length; $i++)
        $children[] = $node->childNodes->item($i);
  
      foreach ($children as $child) {
        $node_name = mb_strtolower($child->nodeName);
        
        // Skip non-displaying nodes
        if ( in_array($node_name, self::$_HIDDEN_TAGS) )  {
          if ( $node_name !== "head" &&
               $node_name !== "style" ) 
            $child->parentNode->removeChild($child);
          continue;
        }
  
        // Skip empty text nodes
        if ( $node_name === "#text" && $child->nodeValue == "" ) {
          $child->parentNode->removeChild($child);
          continue;
        }
  
        // Skip empty image nodes
        if ( $node_name === "img" && $child->getAttribute("src") == "" ) {
          $child->parentNode->removeChild($child);
          continue;
        }
        
        $frame->append_child($this->_build_tree_r($child), false);
      }
      
      return $frame;
    }
    
    public function insert_node(DOMNode $node, DOMNode $new_node, $pos) {
      if ($pos === "after" || !$node->firstChild)
        $node->appendChild($new_node);
      else 
        $node->insertBefore($new_node, $node->firstChild);
      
      $this->_build_tree_r($new_node);
      
      $frame_id = $new_node->getAttribute("frame_id");
      $frame = $this->get_frame($frame_id);
      
      $parent_id = $node->getAttribute("frame_id");
      $parent = $this->get_frame($parent_id);
      
      if ($pos === "before")
        $parent->prepend_child($frame, false);
      else 
        $parent->append_child($frame, false);
    }
  }