<?php
/**
 * CAPTCHA for Image mode
 *
 * Based on DuGris' SecurityImage
 *
 * You may not change or alter any portion of this comment or credits
 * of supporting developers from this source code or any supporting source code
 * which is considered copyrighted (c) material of the original comment or credit authors.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * @copyright       (c) 2000-2016 XOOPS Project (www.xoops.org)
 * @license             GNU GPL 2 (https://www.gnu.org/licenses/gpl-2.0.html)
 * @package             class
 * @subpackage          CAPTCHA
 * @since               2.3.0
 * @author              Taiwen Jiang <phppp@users.sourceforge.net>
 */
defined('XOOPS_ROOT_PATH') || exit('Restricted access');

/**
 * Class XoopsCaptchaImage
 */
class XoopsCaptchaImage extends XoopsCaptchaMethod
{
    /**
     * XoopsCaptchaImage::isActive()
     *
     * @return bool
     */
    public function isActive()
    {
        if (!extension_loaded('gd')) {
            trigger_error('GD library is not loaded', E_USER_WARNING);

            return false;
        } else {
            $required_functions = array(
                'imagecreatetruecolor',
                'imagecolorallocate',
                'imagefilledrectangle',
                'imagejpeg',
                'imagedestroy',
                'imageftbbox');
            foreach ($required_functions as $func) {
                if (!function_exists($func)) {
                    trigger_error('Function ' . $func . ' is not defined', E_USER_WARNING);

                    return false;
                }
            }
        }

        return true;
    }

    /**
     * XoopsCaptchaImage::render()
     *
     * @return string|void
     */
    public function render()
    {
        $js    = "<script type='text/javascript'>
                function xoops_captcha_refresh(imgId)
                {
                    xoopsGetElementById(imgId).src = '" . XOOPS_URL . "/class/captcha/image/scripts/image.php?refresh='+Math.random();
                }
                </script>";
        $image = $this->loadImage();
        $image .= "<br><a href=\"javascript: xoops_captcha_refresh('" . $this->config['name'] . "')\">" . _CAPTCHA_REFRESH . '</a>';
        $input = '<input type="text" name="' . $this->config['name'] . '" id="' . $this->config['name'] . '" size="' . $this->config['num_chars'] . '" maxlength="' . $this->config['num_chars'] . '" value="" />';
        $rule  = _CAPTCHA_RULE_IMAGE;
        $rule .= '<br>' . (empty($this->config['casesensitive']) ? _CAPTCHA_RULE_CASEINSENSITIVE : _CAPTCHA_RULE_CASESENSITIVE);
        if (!empty($this->config['maxattempts'])) {
            $rule .= '<br>' . sprintf(_CAPTCHA_MAXATTEMPTS, $this->config['maxattempts']);
        }

        return $js . $image . '<br><br>' . $input . '<br>' . $rule;
    }

    /**
     * XoopsCaptchaImage::loadImage()
     *
     * @return string
     */
    public function loadImage()
    {
        return '<img id="' . $this->config['name'] . '" src="' . XOOPS_URL . '/class/captcha/image/scripts/image.php" onclick=\'this.src="' . XOOPS_URL . '/class/captcha/image/scripts/image.php?refresh="+Math.random()' . '\' style="cursor: pointer; vertical-align: middle;" alt="" />';
    }
}
