jidaikobo-shibata/a11yc

<?php
/**
 * * A11yc\Validate\Check\EmptyLinkElement
 *
 * @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 EmptyLinkElement extends Validate
{
    /**
     * empty_link_element
     *
     * @param String $url
     * @return Void
     */
    public static function check($url)
    {
        Validate\Set::log($url, 'empty_link_element', self::$unspec, 1);
        $str = Element\Get::ignoredHtml($url);

        $ms = Element\Get::elementsByRe($str, 'ignores', 'anchors_and_values');
        if ( ! $ms[1]) return;

        foreach ($ms[0] as $k => $m)
        {
            if (strpos($m, 'href') === false) continue;
            if (substr($m, 0, 5) === '<area') continue;

            // img's alt
            $text = Element\Get\Each::textFromElement($ms[2][$k]);

            // aria-labelledby
            if (empty($text))
            {
                $text = self::getAriaLabelledby($ms[0][$k], $str, $text);
            }

            // aria-label
            if (empty($text))
            {
                $text = self::getAriaLabel($ms[0][$k], $text);
            }

            Validate\Set::errorAndLog(
                empty($text),
                $url,
                'empty_link_element',
                $k,
                $ms[0][$k],
                $ms[0][$k]
            );
        }
        static::addErrorToHtml($url, 'empty_link_element', static::$error_ids[$url], 'ignores');
    }

    /**
     * getAriaLabelledby
     *
     * @param String $eles
     * @param String $str
     * @param String|Bool $text
     * @return String
     */
    private static function getAriaLabelledby($eles, $str, $text = '')
    {
        $text = is_bool($text) ? '' : $text;

        if (strpos($eles, 'aria-labelledby') !== false)
        {
            $eleses = explode('>', $eles);
            foreach ($eleses as $ele)
            {
                if (strpos($ele, 'aria-labelledby') === false) continue;
                $attrs = Element\Get::attributes($ele.">");
                $ids = Arr::get($attrs, 'aria-labelledby');
                if (empty($ids)) continue; // error but not indicate by here.

                foreach (explode(' ', $ids) as $id)
                {
                    $eachele = Element\Get::elementById($str, $id);
                    $text.= Element\Get\Each::textFromElement($eachele);
                }
            }
        }
        return $text;
    }

    /**
     * getAriaLabel

     sample1:
     <a href="http://example.com" aria-label="foo">
        <span class="fa fa-twitter" aria-label="bar">
            <span aria-label="baz"></span>
        </span>
     </a>

     result:
     sample1 + NVDA: reads "foo". speak from the outside.

     *
     * @param String $eles
     * @param String|Bool $text
     * @return String
     */
    private static function getAriaLabel($eles, $text = '')
    {
        $text = is_bool($text) ? '' : $text;

        if (strpos($eles, 'aria-label') !== false)
        {
            $eleses = explode('>', $eles);
            foreach ($eleses as $ele)
            {
                if (strpos($ele, 'aria-label') === false) continue;
                if ( ! empty($text)) continue;
                $attrs = Element\Get::attributes($ele.">");
                $text.= Arr::get($attrs, 'aria-label', '');
            }
        }

        return $text;
    }
}