<?php

require_once 'HTMLPurifier/AttrDef.php';
require_once 'HTMLPurifier/AttrDef/CSS/Color.php'; // for %Core.ColorKeywords

/**
 * Validates a color according to the HTML spec.
 */
class HTMLPurifier_AttrDef_HTML_Color extends HTMLPurifier_AttrDef
{
    
    function validate($string, $config, &$context) {
        
        static $colors = null;
        if ($colors === null) $colors = $config->get('Core', 'ColorKeywords');
        
        $string = trim($string);
        
        if (empty($string)) return false;
        if (isset($colors[$string])) return $colors[$string];
        if ($string[0] === '#') $hex = substr($string, 1);
        else $hex = $string;
        
        $length = strlen($hex);
        if ($length !== 3 && $length !== 6) return false;
        if (!ctype_xdigit($hex)) return false;
        if ($length === 3) $hex = $hex[0].$hex[0].$hex[1].$hex[1].$hex[2].$hex[2];
        
        return "#$hex";
        
    }
    
}

