<?php
/**
 * @package dompdf
 * @link    http://dompdf.github.com/
 * @author  Benj Carson <benjcarson@digitaljunkies.ca>
 * @author  Fabien Ménager <fabien.menager@gmail.com>
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 */

/**
 * Reflows pages
 *
 * @access private
 * @package dompdf
 */
class Page_Frame_Reflower extends Frame_Reflower {

  /**
   * Cache of the callbacks array
   * 
   * @var array
   */
  private $_callbacks;
  
  /**
   * Cache of the canvas
   *
   * @var Canvas
   */
  private $_canvas;

  function __construct(Page_Frame_Decorator $frame) { parent::__construct($frame); }
  
  function apply_page_style(Frame $frame, $page_number){
    $style = $frame->get_style();
    $page_styles = $style->get_stylesheet()->get_page_styles();
    
    // http://www.w3.org/TR/CSS21/page.html#page-selectors
    if ( count($page_styles) > 1 ) {
      $odd   = $page_number % 2 == 1;
      $first = $page_number == 1;
      
      $style = clone $page_styles["base"];
    
      // FIXME RTL
      if ( $odd && isset($page_styles[":right"]) ) {
        $style->merge($page_styles[":right"]);
      }
      
      if ( $odd && isset($page_styles[":odd"]) ) {
        $style->merge($page_styles[":odd"]);
      }
  
      // FIXME RTL
      if ( !$odd && isset($page_styles[":left"]) ) {
        $style->merge($page_styles[":left"]);
      }
  
      if ( !$odd && isset($page_styles[":even"]) ) {
        $style->merge($page_styles[":even"]);
      }
      
      if ( $first && isset($page_styles[":first"]) ) {
        $style->merge($page_styles[":first"]);
      }
      
      $frame->set_style($style);
    }
  }
  
  //........................................................................

  /**
   * Paged layout:
   * http://www.w3.org/TR/CSS21/page.html
   */
  function reflow(Block_Frame_Decorator $block = null) {
    $fixed_children = array();
    $prev_child = null;
    $child = $this->_frame->get_first_child();
    $current_page = 0;
    
    while ($child) {
      $this->apply_page_style($this->_frame, $current_page + 1);
      
      $style = $this->_frame->get_style();
  
      // Pages are only concerned with margins
      $cb = $this->_frame->get_containing_block();
      $left   = $style->length_in_pt($style->margin_left,   $cb["w"]);
      $right  = $style->length_in_pt($style->margin_right,  $cb["w"]);
      $top    = $style->length_in_pt($style->margin_top,    $cb["h"]);
      $bottom = $style->length_in_pt($style->margin_bottom, $cb["h"]);
      
      $content_x = $cb["x"] + $left;
      $content_y = $cb["y"] + $top;
      $content_width = $cb["w"] - $left - $right;
      $content_height = $cb["h"] - $top - $bottom;
      
      // Only if it's the first page, we save the nodes with a fixed position
      if ($current_page == 0) {
        $children = $child->get_children();
        foreach ($children as $onechild) {
          if ($onechild->get_style()->position === "fixed") {
            $fixed_children[] = $onechild->deep_copy();
          }
        }
        $fixed_children = array_reverse($fixed_children);
      }
      
      $child->set_containing_block($content_x, $content_y, $content_width, $content_height);
      
      // Check for begin reflow callback
      $this->_check_callbacks("begin_page_reflow", $child);
    
      //Insert a copy of each node which have a fixed position
      if ($current_page >= 1) {
        foreach ($fixed_children as $fixed_child) {
          $child->insert_child_before($fixed_child->deep_copy(), $child->get_first_child());
        }
      }
      
      $child->reflow();
      $next_child = $child->get_next_sibling();
      
      // Check for begin render callback
      $this->_check_callbacks("begin_page_render", $child);
      
      // Render the page
      $this->_frame->get_renderer()->render($child);
      
      // Check for end render callback
      $this->_check_callbacks("end_page_render", $child);
      
      if ( $next_child ) {
        $this->_frame->next_page();
      }

      // Wait to dispose of all frames on the previous page
      // so callback will have access to them
      if ( $prev_child ) {
        $prev_child->dispose(true);
      }
      $prev_child = $child;
      $child = $next_child;
      $current_page++;
    }

    // Dispose of previous page if it still exists
    if ( $prev_child ) {
      $prev_child->dispose(true);
    }
  }  
  
  //........................................................................
  
  /**
   * Check for callbacks that need to be performed when a given event
   * gets triggered on a page
   *
   * @param string $event the type of event
   * @param Frame $frame the frame that event is triggered on
   */
  protected function _check_callbacks($event, $frame) {
    if (!isset($this->_callbacks)) {
      $dompdf = $this->_frame->get_dompdf();
      $this->_callbacks = $dompdf->get_callbacks();
      $this->_canvas = $dompdf->get_canvas();
    }
    
    if (is_array($this->_callbacks) && isset($this->_callbacks[$event])) {
      $info = array(0 => $this->_canvas, "canvas" => $this->_canvas,
                    1 => $frame, "frame" => $frame);
      $fs = $this->_callbacks[$event];
      foreach ($fs as $f) {
        if (is_callable($f)) {
          if (is_array($f)) {
            $f[0]->$f[1]($info);
          } else {
            $f($info);
          }
        }
      }
    }
  }  
}
