<?php

namespace WPForms\Vendor;

/**
 * Validates the HTML attribute style, otherwise known as CSS.
 * @note We don't implement the whole CSS specification, so it might be
 *       difficult to reuse this component in the context of validating
 *       actual stylesheet declarations.
 * @note If we were really serious about validating the CSS, we would
 *       tokenize the styles and then parse the tokens. Obviously, we
 *       are not doing that. Doing that could seriously harm performance,
 *       but would make these components a lot more viable for a CSS
 *       filtering solution.
 */
class HTMLPurifier_AttrDef_CSS extends HTMLPurifier_AttrDef
{
    /**
     * @param string $css
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($css, $config, $context)
    {
        $css = $this->parseCDATA($css);
        $definition = $config->getCSSDefinition();
        $allow_duplicates = $config->get("CSS.AllowDuplicates");
        $universal_attrdef = new HTMLPurifier_AttrDef_Enum(array('initial', 'inherit', 'unset'));
        // According to the CSS2.1 spec, the places where a
        // non-delimiting semicolon can appear are in strings
        // escape sequences.   So here is some dumb hack to
        // handle quotes.
        $len = \strlen($css);
        $accum = "";
        $declarations = array();
        $quoted = \false;
        for ($i = 0; $i < $len; $i++) {
            $c = \strcspn($css, ";'\"", $i);
            $accum .= \substr($css, $i, $c);
            $i += $c;
            if ($i == $len) {
                break;
            }
            $d = $css[$i];
            if ($quoted) {
                $accum .= $d;
                if ($d == $quoted) {
                    $quoted = \false;
                }
            } else {
                if ($d == ";") {
                    $declarations[] = $accum;
                    $accum = "";
                } else {
                    $accum .= $d;
                    $quoted = $d;
                }
            }
        }
        if ($accum != "") {
            $declarations[] = $accum;
        }
        $propvalues = array();
        $new_declarations = '';
        /**
         * Name of the current CSS property being validated.
         */
        $property = \false;
        $context->register('CurrentCSSProperty', $property);
        foreach ($declarations as $declaration) {
            if (!$declaration) {
                continue;
            }
            if (!\strpos($declaration, ':')) {
                continue;
            }
            list($property, $value) = \explode(':', $declaration, 2);
            $property = \trim($property);
            $value = \trim($value);
            $ok = \false;
            do {
                if (isset($definition->info[$property])) {
                    $ok = \true;
                    break;
                }
                if (\ctype_lower($property)) {
                    break;
                }
                $property = \strtolower($property);
                if (isset($definition->info[$property])) {
                    $ok = \true;
                    break;
                }
            } while (0);
            if (!$ok) {
                continue;
            }
            $result = $universal_attrdef->validate($value, $config, $context);
            if ($result === \false) {
                $result = $definition->info[$property]->validate($value, $config, $context);
            }
            if ($result === \false) {
                continue;
            }
            if ($allow_duplicates) {
                $new_declarations .= "{$property}:{$result};";
            } else {
                $propvalues[$property] = $result;
            }
        }
        $context->destroy('CurrentCSSProperty');
        // procedure does not write the new CSS simultaneously, so it's
        // slightly inefficient, but it's the only way of getting rid of
        // duplicates. Perhaps config to optimize it, but not now.
        foreach ($propvalues as $prop => $value) {
            $new_declarations .= "{$prop}:{$value};";
        }
        return $new_declarations ? $new_declarations : \false;
    }
}
// vim: et sw=4 sts=4
