<?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
 */

namespace Dompdf\Positioner;

use Dompdf\FrameDecorator\AbstractFrameDecorator;

/**
 * Positions fixely positioned frames
 */
class Fixed extends AbstractPositioner
{

    function __construct(AbstractFrameDecorator $frame)
    {
        parent::__construct($frame);
    }

    function position()
    {

        $frame = $this->_frame;
        $style = $frame->get_original_style();
        $root = $frame->get_root();
        $initialcb = $root->get_containing_block();
        $initialcb_style = $root->get_style();

        $p = $frame->find_block_parent();
        if ($p) {
            $p->add_line();
        }

        // Compute the margins of the @page style
        $margin_top = $initialcb_style->length_in_pt($initialcb_style->margin_top, $initialcb["h"]);
        $margin_right = $initialcb_style->length_in_pt($initialcb_style->margin_right, $initialcb["w"]);
        $margin_bottom = $initialcb_style->length_in_pt($initialcb_style->margin_bottom, $initialcb["h"]);
        $margin_left = $initialcb_style->length_in_pt($initialcb_style->margin_left, $initialcb["w"]);

        // The needed computed style of the element
        $height = $style->length_in_pt($style->height, $initialcb["h"]);
        $width = $style->length_in_pt($style->width, $initialcb["w"]);

        $top = $style->length_in_pt($style->top, $initialcb["h"]);
        $right = $style->length_in_pt($style->right, $initialcb["w"]);
        $bottom = $style->length_in_pt($style->bottom, $initialcb["h"]);
        $left = $style->length_in_pt($style->left, $initialcb["w"]);

        $y = $margin_top;
        if (isset($top)) {
            $y = $top + $margin_top;
            if ($top === "auto") {
                $y = $margin_top;
                if (isset($bottom) && $bottom !== "auto") {
                    $y = $initialcb["h"] - $bottom - $margin_bottom;
                    $margin_height = $this->_frame->get_margin_height();
                    if ($margin_height !== "auto") {
                        $y -= $margin_height;
                    } else {
                        $y -= $height;
                    }
                }
            }
        }

        $x = $margin_left;
        if (isset($left)) {
            $x = $left + $margin_left;
            if ($left === "auto") {
                $x = $margin_left;
                if (isset($right) && $right !== "auto") {
                    $x = $initialcb["w"] - $right - $margin_right;
                    $margin_width = $this->_frame->get_margin_width();
                    if ($margin_width !== "auto") {
                        $x -= $margin_width;
                    } else {
                        $x -= $width;
                    }
                }
            }
        }

        $frame->set_position($x, $y);

        $children = $frame->get_children();
        foreach ($children as $child) {
            $child->set_position($x, $y);
        }
    }
}