jidaikobo-shibata/a11yc

<?php
/**
 * * A11yc\Validate\Check\AppropriateHeadingDescending
 *
 * @package    part of A11yc
 * @author     Jidaikobo Inc.
 * @license    The MIT License (MIT)
 * @copyright  Jidaikobo Inc.
 * @link       http://www.jidaikobo.com
 */
namespace A11yc\Validate\Check;

use A11yc\Element;
use A11yc\Validate;

class AppropriateHeadingDescending extends Validate
{
    /**
     * appropriate heading descending
     *
     * @param String $url
     * @return Void
     */
    public static function check($url)
    {
        Validate\Set::log($url, 'appropriate_heading_descending', self::$unspec, 1);
        $str = Element\Get::ignoredHtml($url);

        $secs = preg_split("/\<(h[^\>?]+?)\>(.+?)\<\/h\d/", $str, -1, PREG_SPLIT_DELIM_CAPTURE);
        if ( ! $secs[0])
        {
            Validate\Set::log($url, 'appropriate_heading_descending', self::$unspec, 4);
            return;
        }

        // get first appeared heading
        $prev = 1;
        foreach ($secs as $sec)
        {
            if (isset($sec[1]) && is_numeric($sec[1]))
            {
                $prev = $sec[1];
                break;
            }
        }

        foreach ($secs as $k => $v)
        {
            if ($v[0] != 'h' || ! is_numeric($v[1])) continue; // skip non heading
            $current_level = $v[1];
            $tstr = '<'.$v.'>';

            if ($current_level - $prev >= 2)
            {
                $str = isset($secs[$k + 1]) ? $secs[$k + 1] : $v[1];
                Validate\Set::error($url, 'appropriate_heading_descending', $k, $tstr, $str);
            }
            else
            {
                Validate\Set::log($url, 'appropriate_heading_descending', $tstr, 2);
            }
            $prev = $current_level;
        }

        static::addErrorToHtml($url, 'appropriate_heading_descending', static::$error_ids[$url], 'ignores');
    }
}