jidaikobo-shibata/a11yc

<?php
/**
 * * A11yc\Validate\Check\NotLabelButTitle
 *
 * @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 NotLabelButTitle extends Validate
{
    /**
     * not_label_but_title
     *
     * @return  bool
     */
    public static function check($url)
    {
        Validate\Set::log($url, 'not_label_but_title', self::$unspec, 1);
        $str = Element\Get::ignoredHtml($url);
        $ms = Element\Get::elementsByRe($str, 'ignores', 'tags');
        if ( ! $ms[0]) return;

        // labels_eles
        list($eles, $fors) = self::setLabelAndElement($ms);

        // no form elements
        if (empty($eles))
        {
            Validate\Set::log($url, 'not_label_but_title', self::$unspec, 4);
            return;
        }

        // find "id" which make pair with existing "for" attribute
        $del_eles = self::setDeleteElement($eles, $fors);

        // find valid "label"s
        $del_fors = self::setDeleteFor($eles, $del_eles);

        // first elimination - delete valid pairs
        foreach ($del_eles as $k)
        {
            unset($eles[$k]);
        }
        foreach ($del_fors as $k)
        {
            unset($eles[$k]);
        }

        // after here, tacit labels or labelless items remain. I hope so...
        // check tacit labels
        $del_eles = self::setSecondaryDeleteElement($str, $eles);

        // second elimination - tacit label
        foreach ($del_eles as $k)
        {
            unset($eles[$k]);
        }

        // after here, remained labels are meanless.
        // check title attribute
        foreach ($eles as $k => $ele)
        {
            if ($ele['tag_name'] == 'label') continue;

            // empty or titleless
            $title = trim(mb_convert_kana($ele['title'], 's'));
            Validate\Set::errorAndLog(
                empty($title),
                $url,
                'not_label_but_title',
                $k,
                $ele['tag'],
                $ele['tag']
            );
        }
        static::addErrorToHtml($url, 'not_label_but_title', static::$error_ids[$url], 'ignores');
    }

    /**
     * set label and element
     *
     * @param Array $ms
     * @return Array
     */
    private static function setLabelAndElement($ms)
    {
        $eles = array();
        $fors = array();

        foreach ($ms[1] as $k => $m)
        {
            if ( ! in_array($m, array('label', 'input', 'textarea', 'select'))) continue;

            $attrs = Element\Get::attributes($ms[0][$k]);
            if ($m == 'label')
            {
                $eles[$k]['tag'] = $ms[0][$k];
                $eles[$k]['tag_name'] = $ms[1][$k];
                $for = isset($attrs['for']) ? $attrs['for'] : '';
                $eles[$k]['for'] = $for;
                if ($for) $fors[] = $for;
            }
            elseif (in_array($m, array('textarea', 'select')))
            {
                $eles[$k]['tag'] = $ms[0][$k];
                $eles[$k]['tag_name'] = $ms[1][$k];
                $eles[$k]['title'] = isset($attrs['title']) ? $attrs['title'] : '';
                $eles[$k]['id'] = isset($attrs['id']) ? $attrs['id'] : '';
            }
            elseif ($m == 'input')
            {
                // typeless means text
                $attrs['type'] = isset($attrs['type']) ? $attrs['type'] : 'text';

                // target attributes
                if (in_array($attrs['type'], array('text', 'checkbox', 'radio', 'file', 'password')))
                {
                    $eles[$k]['tag'] = $ms[0][$k];
                    $eles[$k]['tag_name'] = $ms[1][$k];
                    $eles[$k]['title'] = isset($attrs['title']) ? $attrs['title'] : '';
                    $eles[$k]['id'] = isset($attrs['id']) ? $attrs['id'] : '';
                }
            }
        }
        return array($eles, $fors);
    }

    /**
     * set delete element
     *
     * @param Array $eles
     * @param Array $fors
     * @return Array
     */
    private static function setDeleteElement($eles, $fors)
    {
        $del_eles = array();
        foreach ($fors as $for)
        {
            foreach ($eles as $k => $ele)
            {
                // pick up target ids
                if (isset($ele['id']) && $ele['id'] == $for)
                {
                    // id must be unique
                    if (array_key_exists($for, $del_eles)) continue;
                    $del_eles[$for] = $k;
                }
            }
        }
        return $del_eles;
    }

    /**
     * set delete for
     *
     * @param Array $eles
     * @param Array $del_eles
     * @return Array
     */
    private static function setDeleteFor($eles, $del_eles)
    {
        $del_fors = array();
        foreach (array_keys($del_eles) as $id)
        {
            foreach ($eles as $k => $ele)
            {
                // pick up target fors
                if (isset($ele['for']) && $ele['for'] == $id)
                {
                    // for must NOT be unique
                    $del_fors[] = $k;
                }
            }
        }
        return $del_fors;
    }

    /**
     * set secondary delete element
     *
     * @param String $str
     * @param Array $eles
     * @return Array
     */
    private static function setSecondaryDeleteElement($str, $eles)
    {
        $del_eles = array();
        $pattern = '/\<label[^\>]*?\>.*?\<\/label\>/is';
        preg_match_all($pattern, $str, $mms);

        if ($mms[0])
        {
            foreach ($mms[0] as $m)
            {
                $prev = '';
                foreach ($eles as $k => $ele)
                {
                    if ($ele['tag_name'] == 'label')
                    {
                        $prev = $k;
                    }
                    elseif (strpos($m, $ele['tag']) !== false)
                    {
                        $del_eles[] = $prev;
                        $del_eles[] = $k;
                    }
                }
            }
        }
        return $del_eles;
    }
}