<?php

/**
 * nbbc parser
 * 
 * PHP version 5
 * 
 * @category  JFusion
 * @package   Models
 * @author    reCAPTCHA <webmaster@jfusion.org>
 * @copyright 2008 reCAPTCHA. All rights reserved.
 * @license   http://www.gnu.org/copyleft/gpl.html GNU/GPL
 * @link      http://www.jfusion.org
 */

/*
* This is a PHP library that handles calling reCAPTCHA.
*    - Documentation and latest version
*          http://recaptcha.net/plugins/php/
*    - Get a reCAPTCHA API Key
*          http://recaptcha.net/api/getkey
*    - Discussion group
*          http://groups.google.com/group/recaptcha
*
* Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
* AUTHORS:
*   Mike Crawford
*   Ben Maurer
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/**
 * The reCAPTCHA server URL's
 */
define("RECAPTCHA_API_SERVER", "http://api.recaptcha.net");
define("RECAPTCHA_API_SECURE_SERVER", "https://api-secure.recaptcha.net");
define("RECAPTCHA_VERIFY_SERVER", "api-verify.recaptcha.net");
/**
 * Encodes the given data into a query string format
 * @param $data - array of string elements to be encoded
 * @return string - encoded request
 */
function _recaptcha_qsencode($data) {
    $req = '';
    foreach ($data as $key => $value) $req.= $key . '=' . urlencode(stripslashes($value)) . '&';
    // Cut the last '&'
    $req = substr($req, 0, strlen($req) - 1);
    return $req;
}
/**
 * Submits an HTTP POST to a reCAPTCHA server
 * @param string $host
 * @param string $path
 * @param array $data
 * @param int port
 * @return array response
 */
function _recaptcha_http_post($host, $path, $data, $port = 80) {
    $req = _recaptcha_qsencode($data);
    $http_request = "POST $path HTTP/1.0\r\n";
    $http_request.= "Host: $host\r\n";
    $http_request.= "Content-Type: application/x-www-form-urlencoded;\r\n";
    $http_request.= "Content-Length: " . strlen($req) . "\r\n";
    $http_request.= "User-Agent: reCAPTCHA/PHP\r\n";
    $http_request.= "\r\n";
    $http_request.= $req;
    $response = '';
    if (false == ($fs = @fsockopen($host, $port, $errno, $errstr, 10))) {
        die('Could not open socket');
    }
    fwrite($fs, $http_request);
    while (!feof($fs)) $response.= fgets($fs, 1160); // One TCP-IP packet
    fclose($fs);
    $response = explode("\r\n\r\n", $response, 2);
    return $response;
}
/**
 * Gets the challenge HTML (javascript and non-javascript version).
 * This is called from the browser, and the resulting reCAPTCHA HTML widget
 * is embedded within the HTML form it was called from.
 * @param string $pubkey A public key for reCAPTCHA
 * @param string $error The error given by reCAPTCHA (optional, default is null)
 * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
 * @return string - The HTML to be embedded in the user's form.
 */
function recaptcha_get_html($pubkey, $error = null, $use_ssl = false) {
    if ($pubkey == null || $pubkey == '') {
        die("To use reCAPTCHA you must get an API key from <a href='http://recaptcha.net/api/getkey'>http://recaptcha.net/api/getkey</a>");
    }
    if ($use_ssl) {
        $server = RECAPTCHA_API_SECURE_SERVER;
    } else {
        $server = RECAPTCHA_API_SERVER;
    }
    $errorpart = '';
    if ($error) {
        $errorpart = '&amp;error=' . $error;
    }
    return '<script type="text/javascript" src="' . $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>

    <noscript>
          <iframe src="' . $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
          <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
          <input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
    </noscript>';
}
/**
 * A ReCaptchaResponse is returned from recaptcha_check_answer()
 * 
 * @category  JFusion
 * @package   Models
 * @author    reCAPTCHA <webmaster@jfusion.org>
 * @copyright 2008 reCAPTCHA. All rights reserved.
 * @license   http://www.gnu.org/copyleft/gpl.html GNU/GPL
 * @link      http://www.jfusion.org
 */
class ReCaptchaResponse {
    var $is_valid;
    var $error;
}
/**
 * Calls an HTTP POST function to verify if the user's guess was correct
 * @param string $privkey
 * @param string $remoteip
 * @param string $challenge
 * @param string $response
 * @param array $extra_params an array of extra variables to post to the server
 * @return ReCaptchaResponse
 */
function recaptcha_check_answer($privkey, $remoteip, $challenge, $response, $extra_params = array()) {
    if ($privkey == null || $privkey == '') {
        die("To use reCAPTCHA you must get an API key from <a href='http://recaptcha.net/api/getkey'>http://recaptcha.net/api/getkey</a>");
    }
    if ($remoteip == null || $remoteip == '') {
        die("For security reasons, you must pass the remote ip to reCAPTCHA");
    }
    //discard spam submissions
    if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
        $recaptcha_response = new ReCaptchaResponse();
        $recaptcha_response->is_valid = false;
        $recaptcha_response->error = 'incorrect-captcha-sol';
        return $recaptcha_response;
    }
    $response = _recaptcha_http_post(RECAPTCHA_VERIFY_SERVER, "/verify", array('privatekey' => $privkey, 'remoteip' => $remoteip, 'challenge' => $challenge, 'response' => $response) + $extra_params);
    $answers = explode("\n", $response[1]);
    $recaptcha_response = new ReCaptchaResponse();
    if (trim($answers[0]) == 'true') {
        $recaptcha_response->is_valid = true;
    } else {
        $recaptcha_response->is_valid = false;
        $recaptcha_response->error = $answers[1];
    }
    return $recaptcha_response;
}
/**
 * gets a URL where the user can sign up for reCAPTCHA. If your application
 * has a configuration page where you enter a key, you should provide a link
 * using this function.
 * @param string $domain The domain where the page is hosted
 * @param string $appname The name of your application
 *
 * @return string
 */
function recaptcha_get_signup_url($domain = null, $appname = null) {
    return "http://recaptcha.net/api/getkey?" . _recaptcha_qsencode(array('domain' => $domain, 'app' => $appname));
}

/**
 * @param $val
 * @return string
 */
function _recaptcha_aes_pad($val) {
    $block_size = 16;
    $numpad = $block_size - (strlen($val) % $block_size);
    return str_pad($val, strlen($val) + $numpad, chr($numpad));
}

/**
 * Mailhide related code
 *
 * @param $val
 * @param $ky
 * @return string
 */
function _recaptcha_aes_encrypt($val, $ky) {
    if (!function_exists("mcrypt_encrypt")) {
        die("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
    }
    $mode = MCRYPT_MODE_CBC;
    $enc = MCRYPT_RIJNDAEL_128;
    $val = _recaptcha_aes_pad($val);
    return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
}

/**
 * @param $x
 * @return string
 */
function _recaptcha_mailhide_urlbase64($x) {
    return strtr(base64_encode($x), '+/', '-_');
}
/**
 * gets the reCAPTCHA Mailhide url for a given email, public key and private key
 *
 * @param $pubkey
 * @param $privkey
 * @param $email
 * @return string
 */
function recaptcha_mailhide_url($pubkey, $privkey, $email) {
    if ($pubkey == '' || $pubkey == null || $privkey == "" || $privkey == null) {
        die("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " . "you can do so at <a href='http://mailhide.recaptcha.net/apikey'>http://mailhide.recaptcha.net/apikey</a>");
    }
    $ky = pack('H*', $privkey);
    $cryptmail = _recaptcha_aes_encrypt($email, $ky);
    return "http://mailhide.recaptcha.net/d?k=" . $pubkey . "&c=" . _recaptcha_mailhide_urlbase64($cryptmail);
}
/**
 * gets the parts of the email to expose to the user.
 * eg, given johndoe@example,com return ["john", "example.com"].
 * the email is then displayed as john...@example.com
 *
 * @param string $email
 *
 * @return array
 */
function _recaptcha_mailhide_email_parts($email) {
    $arr = preg_split("/@/", $email);
    if (strlen($arr[0]) <= 4) {
        $arr[0] = substr($arr[0], 0, 1);
    } else if (strlen($arr[0]) <= 6) {
        $arr[0] = substr($arr[0], 0, 3);
    } else {
        $arr[0] = substr($arr[0], 0, 4);
    }
    return $arr;
}
/**
 * Gets html to display an email address given a public an private key.
 * to get a key, go to:
 *
 * http://mailhide.recaptcha.net/apikey
 *
 * @param string $pubkey
 * @param string $privkey
 * @param string $email
 *
 * @return string
 */
function recaptcha_mailhide_html($pubkey, $privkey, $email) {
    $emailparts = _recaptcha_mailhide_email_parts($email);
    $url = recaptcha_mailhide_url($pubkey, $privkey, $email);
    return htmlentities($emailparts[0]) . "<a href='" . htmlentities($url) . "' onclick=\"window.open('" . htmlentities($url) . "', '', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,height=300'); return false;\" title=\"Reveal this e-mail address\">...</a>@" . htmlentities($emailparts[1]);
}