<?php
/*
 * 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
 */
/* old URLs
define("RSC_RECAPTCHA_API_SERVER", "http://api.recaptcha.net");
define("RSC_RECAPTCHA_API_SECURE_SERVER", "https://api-secure.recaptcha.net");
define("RSC_RECAPTCHA_VERIFY_SERVER", "api-verify.recaptcha.net");
*/

define("RSFE_RECAPTCHA_API_SERVER", "http://www.google.com/recaptcha/api");
define("RSFE_RECAPTCHA_API_SECURE_SERVER", "https://www.google.com/recaptcha/api");
define("RSFE_RECAPTCHA_VERIFY_SERVER", "www.google.com");

class JReCAPTCHA
{
	/**
	 * Encodes the given data into a query string format
	 * @param $data - array of string elements to be encoded
	 * @return string - encoded request
	 */
	public static function qsencode ($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 $data
	 * @param int port
	 * @return array response
	 */
	public static function post($host, $path, $data, $port = 80)
	{
		$req = JReCAPTCHA::qsencode ($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, $errstr, 10) ) ) {
			throw new Exception('RSFeedback! ReCAPTCHA: Could not open socket. Please check that your server can connect to '.$host,404);
			return false;
		}

		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.
	 */
	public static function getHTML ($error = null, $use_ssl = false)
	{
		$rsfeedbackConfig = RSFeedbackHelper::getConfig();
		$pubkey = $rsfeedbackConfig->rec_public;

		if ($pubkey == null || $pubkey == '') {
			return "To use reCAPTCHA you must get an API key from <a href='http://recaptcha.net/api/getkey'>http://recaptcha.net/api/getkey</a>";
		}
		
		$return = ' <script type="text/javascript">var RecaptchaOptions = { theme : \''.$rsfeedbackConfig->rec_themes.'\' };</script>';
		
		$jconfig = new JConfig();
		$use_ssl = isset($jconfig->force_ssl) && $jconfig->force_ssl == 2;
		if ($use_ssl)
			$server = RSFE_RECAPTCHA_API_SECURE_SERVER;
		else
			$server = RSFE_RECAPTCHA_API_SERVER;

			$errorpart = "";
			if ($error) {
			   $errorpart = "&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>';
		
		return $return;
	}

	/**
	  * 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 $extra_params an array of extra variables to post to the server
	  * @return ReCaptchaResponse
	  */
	public static function checkAnswer ($privkey, $remoteip, $challenge, $response, $extra_params = array())
	{
		if ($privkey == null || $privkey == '') {
			throw new Exception('To use reCAPTCHA you must get an API key from <a href="http://recaptcha.net/api/getkey">http://recaptcha.net/api/getkey</a>', 404);
			return false;
		}

		if ($remoteip == null || $remoteip == '') {
			throw new Exception('For security reasons, you must pass the remote IP to reCAPTCHA. We could not detect your IP.', 404);
			return false;
		}
		
			//discard spam submissions
			if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
					$recaptcha_response = new JReCAPTCHAResponse();
					$recaptcha_response->is_valid = false;
					$recaptcha_response->error = 'incorrect-captcha-sol';
					return $recaptcha_response;
			}

			$response = JReCAPTCHA::post (RSFE_RECAPTCHA_VERIFY_SERVER, "/recaptcha/api/verify",
											  array (
													 'privatekey' => $privkey,
													 'remoteip' => $remoteip,
													 'challenge' => $challenge,
													 'response' => $response
													 ) + $extra_params
											  );

			$answers = explode ("\n", $response [1]);
			$recaptcha_response = new JReCAPTCHAResponse();

			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 $appname The name of your application
	 */
	public static function get_signup_url ($domain = null, $appname = null) {
		return "http://recaptcha.net/api/getkey?" .  JReCAPTCHA::qsencode (array ('domain' => $domain, 'app' => $appname));
	}
}

/**
 * A JReCAPTCHAResponse is returned from recaptcha_check_answer()
 */
class JReCAPTCHAResponse
{
	var $is_valid;
	var $error;
}