<?php

/**
 * Decorator which enables !important to be used in CSS values.
 */
class HTMLPurifier_AttrDef_CSS_ImportantDecorator extends HTMLPurifier_AttrDef
{
    protected $def, $allow;
    
    /**
     * @param $def Definition to wrap
     * @param $allow Whether or not to allow !important
     */
    public function __construct($def, $allow = false) {
        $this->def = $def;
        $this->allow = $allow;
    }
    /**
     * Intercepts and removes !important if necessary
     */
    public function validate($string, $config, $context) {
        // test for ! and important tokens
        $string = trim($string);
        $is_important = false;
        // :TODO: optimization: test directly for !important and ! important
        if (strlen($string) >= 9 && substr($string, -9) === 'important') {
            $temp = rtrim(substr($string, 0, -9));
            // use a temp, because we might want to restore important
            if (strlen($temp) >= 1 && substr($temp, -1) === '!') {
                $string = rtrim(substr($temp, 0, -1));
                $is_important = true;
            }
        }
        $string = $this->def->validate($string, $config, $context);
        if ($this->allow && $is_important) $string .= ' !important';
        return $string;
    }
}
