<?php

    /**
     * @author David J. Malan <malan@harvard.edu>
     * @link https://manual.cs50.net/CS50_Library
     * @package CS50
     * @version 0.12
     *
     * Creative Commons Attribution-ShareAlike 3.0 Unported Licence
     * http://creativecommons.org/licenses/by-sa/3.0/
     */

    // require extensions for Janrain OpenID libary
    if (!extension_loaded("curl"))
    	trigger_error("CS50 Library requires curl extension module", E_USER_ERROR);
    if (!extension_loaded("dom") && !extension_loaded("domxml"))
    	trigger_error("CS50 Library requires dom or domxml extension module", E_USER_ERROR);
    if (!extension_loaded("bcmath") && !extension_loaded("gmp"))
    	trigger_error("CS50 Library requires bcmath or gmp extension module", E_USER_ERROR);

    // CS50
    class CS50
    {
        /**
         * Returns URL to which user can be directed for 
         * authentication via CS50 ID.
         *
         * @param directory   path to directory in which to store state
         * @param trust_root  URL that CS50 ID should prompt user to trust
         * @param return_to   URL to which CS50 ID should return user
         * @param fields      Simple Registration fields to request from CS50 ID
         * @param attributes  Attribute Exchange attributes to request from CS50 ID
         *
         * @return URL for CS50 ID
         */
        static function getLoginUrl($directory, $trust_root, $return_to, $fields = array("email", "fullname"), $attributes = array())
        {
            // ignore Janrain's use of deprecated functions
            $error_reporting = error_reporting();
            error_reporting($error_reporting ^ E_DEPRECATED);

            // require Janrain OpenID libary
            $include_path = get_include_path();
            set_include_path($include_path . PATH_SEPARATOR . dirname(__FILE__) . "/share/openid-php-openid-2.2.2");
            require_once("Auth/OpenID/AX.php");
            require_once("Auth/OpenID/Consumer.php");
            require_once("Auth/OpenID/FileStore.php");
            require_once("Auth/OpenID/SReg.php");

            // ensure $_SESSION exists for Yadis
            @session_start();

            // prepare request
            $consumer = new Auth_OpenID_Consumer(new Auth_OpenID_FileStore($directory));
            $auth_request = $consumer->begin("https://id.cs50.net/");

            // request Simple Registration fields
            if (is_array($fields) && count($fields) > 0)
            {
                $sreg_request = Auth_OpenID_SRegRequest::build(null, $fields);
                $auth_request->addExtension($sreg_request);
            }

            // request Attribute Exchange attributes
            if (is_array($attributes) && count($attributes) > 0)
            {
                $ax_request = new Auth_OpenID_AX_FetchRequest();
                foreach ($attributes as $attribute)
                    $ax_request->add(Auth_OpenID_AX_AttrInfo::make($attribute, 1, false));
                $auth_request->addExtension($ax_request);
            }

            // generate URL for redirection
            $redirect_url = $auth_request->redirectURL($trust_root, $return_to);

            // restore error_reporting
            error_reporting($error_reporting);

            // restore include_path
            set_include_path($include_path);

            // return URL unless error
            if (Auth_OpenID::isFailure($redirect_url))
            {
                trigger_error($redirect_url->message);
                return false;
            }
            else
                return $redirect_url;
        }
 
        /**
         * Iff user was authenticated (at URL returned by getLoginUrl),
         * returns associative array that WILL contain user's Harvard email
         * address (mail) and that MAY contain user's name (displayName).
         *
         * @param directory  path to directory in which to store state
         * @param return_to  URL to which CS50 ID returned user
         *
         * @return user as associative array
         */
        static function getUser($directory, $return_to)
        {
            // ignore Janrain's use of deprecated functions
            $error_reporting = error_reporting();
            error_reporting($error_reporting ^ E_DEPRECATED);

            // require Janrain OpenID libary
            $include_path = get_include_path();
            set_include_path($include_path . PATH_SEPARATOR . dirname(__FILE__) . "/share/openid-php-openid-2.2.2");
            require_once("Auth/OpenID/AX.php");
            require_once("Auth/OpenID/Consumer.php");
            require_once("Auth/OpenID/FileStore.php");
            require_once("Auth/OpenID/SReg.php");

            // ensure $_SESSION exists for Yadis
            @session_start();

            // get response
            $consumer = new Auth_OpenID_Consumer(new Auth_OpenID_FileStore($directory));
            $response = $consumer->complete($return_to);
            if ($response->status == Auth_OpenID_SUCCESS)
            {
                // get user's identity
                $user = array("identity" => $response->identity_url);

                // get Simple Registration fields, if any
                if ($sreg_resp = Auth_OpenID_SRegResponse::fromSuccessResponse($response))
                    $user = array_merge($user, $sreg_resp->contents());

                // get Attribute Exchange attributes, if any
                if ($ax_resp = Auth_OpenID_AX_FetchResponse::fromSuccessResponse($response))
                    $user = array_merge($user, $ax_resp->data);

                // return user
                return $user;
            }
            else
                return false;
        }
    }

?>