<?php
/**
 * This is a PHP library that handles calling reCAPTCHA.
 *
 * @copyright Copyright (c) 2015, Google Inc.
 * @link      http://www.google.com/recaptcha
 *
 * 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.
 */

namespace ReCaptcha\RequestMethod;

use ReCaptcha\RequestMethod;
use ReCaptcha\RequestParameters;

/**
 * Sends a POST request to the reCAPTCHA service, but makes use of fsockopen()
 * instead of get_file_contents(). This is to account for people who may be on
 * servers where allow_url_open is disabled.
 */
class SocketPost implements RequestMethod {

	/**
	 * reCAPTCHA service host.
	 *
	 * @const string
	 */
	const RECAPTCHA_HOST = 'www.google.com';

	/**
	 * @const string reCAPTCHA service path
	 */
	const SITE_VERIFY_PATH = '/recaptcha/api/siteverify';

	/**
	 * @const string Bad request error
	 */
	const BAD_REQUEST = '{"success": false, "error-codes": ["invalid-request"]}';

	/**
	 * @const string Bad response error
	 */
	const BAD_RESPONSE = '{"success": false, "error-codes": ["invalid-response"]}';

	/**
	 * Socket to the reCAPTCHA service
	 *
	 * @var Socket
	 */
	private $socket;

	/**
	 * Constructor
	 *
	 * @param \ReCaptcha\RequestMethod\Socket $socket optional socket, injectable for testing
	 */
	public function __construct( Socket $socket = null ) {
		if ( ! is_null( $socket ) ) {
			$this->socket = $socket;
		} else {
			$this->socket = new Socket();
		}
	}

	/**
	 * Submit the POST request with the specified parameters.
	 *
	 * @param RequestParameters $params Request parameters
	 * @return string Body of the reCAPTCHA response
	 */
	public function submit( RequestParameters $params ) {
		$errno  = 0;
		$errstr = '';

		if ( false === $this->socket->fsockopen( 'ssl://' . self::RECAPTCHA_HOST, 443, $errno, $errstr, 30 ) ) {
			return self::BAD_REQUEST;
		}

		$content = $params->toQueryString();

		$request  = 'POST ' . self::SITE_VERIFY_PATH . " HTTP/1.1\r\n";
		$request .= 'Host: ' . self::RECAPTCHA_HOST . "\r\n";
		$request .= "Content-Type: application/x-www-form-urlencoded\r\n";
		$request .= 'Content-length: ' . strlen( $content ) . "\r\n";
		$request .= "Connection: close\r\n\r\n";
		$request .= $content . "\r\n\r\n";

		$this->socket->fwrite( $request );
		$response = '';

		while ( ! $this->socket->feof() ) {
			$response .= $this->socket->fgets( 4096 );
		}

		$this->socket->fclose();

		if ( 0 !== strpos( $response, 'HTTP/1.1 200 OK' ) ) {
			return self::BAD_RESPONSE;
		}

		$parts = preg_split( "#\n\s*\n#Uis", $response );

		return $parts[1];
	}
}
