<?php
/* For licensing terms, see /license.txt */
/**
 *
 *                             SCRIPT PURPOSE
 *
 * This script initializes and manages Chamilo session information. It
 * keeps available session information up to date.
 *
 * You can request a course id. It will check if the course Id requested is the
 * same as the current one. If it isn't it will update session information from
 * the database. You can also force the course reset if you want ($cidReset).
 *
 * All the course information is stored in the $_course array.
 *
 * You can request a group id. The script will check if the group id requested is the
 * same as the current one. If it isn't it will update session information from
 * the database. You can also force the course reset if you want ($gidReset).
 *
The course id is stored in $_cid session variable.
 * The group  id is stored in $_gid session variable.
 *
 *
 *                    VARIABLES AFFECTING THE SCRIPT BEHAVIOR
 *
 * string  $login
 * string  $password
 * boolean $logout
 *
 * string  $cidReq   : course id requested
 * boolean $cidReset : ask for a course Reset, if no $cidReq is provided in the
 *                     same time, all course informations is removed from the
 *                     current session
 *
 * int     $gidReq   : group Id requested
 * boolean $gidReset : ask for a group Reset, if no $gidReq is provided in the
 *                     same time, all group informations is removed from the
 *                     current session
 *
 *
 *                   VARIABLES SET AND RETURNED BY THE SCRIPT
 *
 * All the variables below are set and returned by this script.
 *
 * USER VARIABLES
 *
 * string    $_user ['firstName'   ]
 * string    $_user ['lastName'    ]
 * string    $_user ['mail'        ]
 * string    $_user ['lastLogin'   ]
 * string    $_user ['official_code']
 * string    $_user ['picture_uri'  ]
 * string    $_user['user_id']
 *
 * boolean $is_platformAdmin
 * boolean $is_allowedCreateCourse
 *
 * COURSE VARIABLES
 *
 * string  $_cid (the course id)
 *
 * int     $_course['id'          ] - auto-assigned integer
 * string  $_course['name'        ] - the title of the course
 * string  $_course['official_code']    - the visual / fake / official code
 * string  $_course['sysCode'     ]
 * string  $_course['path'        ]
 * string  $_course['dbName'      ]
 * string  $_course['dbNameGlu'   ]
 * string  $_course['titular'     ]
 * string  $_course['language'    ]
 * string  $_course['extLink'     ]['url' ]
 * string  $_course['extLink'     ]['name']
 * string  $_course['categoryCode']
 * string  $_course['categoryName']

 * boolean $is_courseMember
 * boolean $is_courseTutor
 * boolean $is_courseAdmin
 *
 *
 * GROUP VARIABLES
 *
 * int     $_gid (the group id)
 *
 *
 *                       IMPORTANT ADVICE FOR DEVELOPERS
 *
 * We strongly encourage developers to use a connection layer at the top of
 * their scripts rather than use these variables, as they are, inside the core
 * of their scripts. It will make code maintenance much easier.
 *
 *    Many if the functions you need you can already find in the
 *    main_api.lib.php
 *
 * We encourage you to use functions to access these global "kernel" variables.
 * You can add them to e.g. the main API library.
 *
 *
 *                               SCRIPT STRUCTURE
 *
 * 1. The script determines if there is an authentication attempt. This part
 * only chek if the login name and password are valid. Afterwards, it set the
 * $_user['user_id'] (user id) and the $uidReset flag. Other user informations are retrieved
 * later. It's also in this section that optional external authentication
 * devices step in.
 *
 * 2. The script determines what other session informations have to be set or
 * reset, setting correctly $cidReset (for course) and $gidReset (for group).
 *
 * 3. If needed, the script retrieves the other user informations (first name,
 * last name, ...) and stores them in session.
 *
 * 4. If needed, the script retrieves the course information and stores them
 * in session
 *
 * 5. The script initializes the user permission status and permission for the
 * course level
 *
 * 6. If needed, the script retrieves group informations an store them in
 * session.
 *
 * 7. The script initializes the user status and permission for the group level.
 *
 *    @package chamilo.include
*/
/*
        INIT SECTION
        variables should be initialised here
*/

require_once (api_get_path(LIBRARY_PATH).'course.lib.php');

// verified if exists the username and password in session current
if (isset($_SESSION['info_current_user'][1]) && isset($_SESSION['info_current_user'][2])) {
    require_once (api_get_path(LIBRARY_PATH).'usermanager.lib.php');
    require_once (api_get_path(LIBRARY_PATH).'legal.lib.php');
}
// parameters passed via GET
$logout = isset($_GET["logout"]) ? $_GET["logout"] : '';
$gidReq = isset($_GET["gidReq"]) ? Database::escape_string($_GET["gidReq"]) : '';

//this fixes some problems with generic functionalities like
//My Agenda & What's New icons linking to courses
// $cidReq can be set in the index.php file of a course-area
$cidReq = isset($cidReq) ? Database::escape_string($cidReq) : '';
// $cidReq can be set in URL-parameter
$cidReq = isset($_GET["cidReq"]) ? Database::escape_string($_GET["cidReq"]) : $cidReq;

$cidReset = isset($cidReset) ? Database::escape_string($cidReset) : '';

// $cidReset can be set in URL-parameter
$cidReset = (isset($_GET['cidReq']) && ((isset($_SESSION['_cid']) && $_GET['cidReq']!=$_SESSION['_cid']) || (!isset($_SESSION['_cid'])))) ? Database::escape_string($_GET["cidReq"]) : $cidReset;

// $cDir is a special url param sent by courses/.htaccess
$cDir = (!empty($_GET['cDir']) ? $_GET['cDir'] : null);

$gidReset = isset($gidReset) ? $gidReset : '';
// $gidReset can be set in URL-parameter

// parameters passed via POST
$login = isset($_POST["login"]) ? $_POST["login"] : '';

// passed through other means
//$cidReq -- passed from course folder index.php

/*
        MAIN CODE
*/

if (!empty($_SESSION['_user']['user_id']) && ! ($login || $logout)) {
    // uid is in session => login already done, continue with this value
    $_user['user_id'] = $_SESSION['_user']['user_id'];
} else {
    if (isset($_user['user_id'])) {
        unset($_user['user_id']);
    }

    //$_SESSION['info_current_user'][1] is user name
    //$_SESSION['info_current_user'][2] is current password encrypted
    //$_SESSION['update_term_and_condition'][1] is current user id, of user in session
    if (api_get_setting('allow_terms_conditions')=='true') {
        if (isset($_POST['login']) && isset($_POST['password']) && isset($_SESSION['update_term_and_condition'][1])) {

             $user_id=$_SESSION['update_term_and_condition'][1];    // user id
            // update the terms & conditions

            //verify type of terms and conditions
            $info_legal = explode(':',$_POST['legal_info']);
            $legal_type=LegalManager::get_type_of_terms_and_conditions($info_legal[0],$info_legal[1]);

            //is necessary verify check
            if ($legal_type==1) {
                if ((isset($_POST['legal_accept']) && $_POST['legal_accept']=='1')) {
                    $legal_option=true;
                } else {
                    $legal_option=false;

                }
            }
            //no is check option
            if ($legal_type==0) {
                $legal_option=true;
            }

            if (isset($_POST['legal_accept_type']) && $legal_option===true) {
                $cond_array = explode(':',$_POST['legal_accept_type']);
                if (!empty($cond_array[0]) && !empty($cond_array[1])){
                    $time = time();
                    $condition_to_save = intval($cond_array[0]).':'.intval($cond_array[1]).':'.$time;
                    UserManager::update_extra_field_value($user_id,'legal_accept',$condition_to_save);

                }
            }
        }
    }

    if ((isset($_POST['login']) && isset($_POST['password']))) {
        // $login && $password are given to log in
        $login = $_POST['login'];
        $password = $_POST['password'];

        //lookup the user in the main database
        $user_table = Database::get_main_table(TABLE_MAIN_USER);
        $sql = "SELECT user_id, username, password, auth_source, active, expiration_date
                FROM $user_table
                WHERE username = '".Database::escape_string($login)."'";
        $result = Database::query($sql);

        if (Database::num_rows($result) > 0) {
            $uData = Database::fetch_array($result);

            if ($uData['auth_source'] == PLATFORM_AUTH_SOURCE) {
                //the authentification of this user is managed by Chamilo itself
                $password = trim(stripslashes($password));
                // determine if the password needs to be encrypted before checking
                // $userPasswordCrypted is set in an external configuration file

                /*if ($userPasswordCrypted) {
                    $password = md5($password);
                } */
                if (api_get_setting('allow_terms_conditions')=='true') {
                    if (isset($_POST['password']) && isset($_SESSION['info_current_user'][2]) && $_POST['password']==$_SESSION['info_current_user'][2]) {
                        $password=$_POST['password'];
                    } else {
                           $password = api_get_encrypted_password($password);
                    }
                } else {
                    $password = api_get_encrypted_password($password);
                }
                if (api_get_setting('allow_terms_conditions')=='true') {
                   if ($password == $uData['password'] AND (trim($login) == $uData['username'])) {
                        $temp_user_id = $uData['user_id'];
                        $term_and_condition_status=api_check_term_condition($temp_user_id);//false or true
                        if ($term_and_condition_status===false) {
                            $_SESSION['update_term_and_condition']=array(true,$temp_user_id);
                            $_SESSION['info_current_user']=array(true,$login,$password);
                            header('Location: '.api_get_path(WEB_CODE_PATH).'auth/inscription.php');
                            exit;
                        } else {
                            unset($_SESSION['update_term_and_condition']);
                            unset($_SESSION['info_current_user']);
                        }

                    }
                }

               // Check the user's password
                if ($password == $uData['password'] AND (trim($login) == $uData['username'])) {
                    // Check if the account is active (not locked)
                    if ($uData['active']=='1') {
                        // Check if the expiration date has not been reached
                        if ($uData['expiration_date']>date('Y-m-d H:i:s') OR $uData['expiration_date']=='0000-00-00 00:00:00') {
                            global $_configuration;

                            if ($_configuration['multiple_access_urls']) {
                                $admin_table = Database::get_main_table(TABLE_MAIN_ADMIN);

                                //Check if user is an admin
                                $sql = "SELECT user_id FROM $admin_table
                                        WHERE user_id = '".intval($uData['user_id'])."' LIMIT 1";
                                $result = Database::query($sql);

                                $my_user_is_admin = false;
                                if (Database::num_rows($result) > 0) {
                                    $my_user_is_admin = true;
                                }

                                // This user is subscribed in these sites => $my_url_list
                                $my_url_list = api_get_access_url_from_user($uData['user_id']);

                                //Check the access_url configuration setting if the user is registered in the access_url_rel_user table
                                //Getting the current access_url_id of the platform
                                $current_access_url_id = api_get_current_access_url_id();

                                if ($my_user_is_admin === false) {

                                    if (is_array($my_url_list) && count($my_url_list)>0 ){
                                        // the user have the permissions to enter at this site
                                        if (in_array($current_access_url_id, $my_url_list)) {
                                            $_user['user_id'] = $uData['user_id'];
                                            api_session_register('_user');
                                            event_login();
                                        } else {
                                            $loginFailed = true;
                                            api_session_unregister('_uid');
                                            header('Location: '.api_get_path(WEB_PATH).'index.php?loginFailed=1&error=access_url_inactive');
                                            exit;
                                        }
                                    } else {
                                        $loginFailed = true;
                                        api_session_unregister('_uid');
                                        header('Location: '.api_get_path(WEB_PATH).'index.php?loginFailed=1&error=access_url_inactive');
                                        exit;
                                    }
                                } else { //Only admins of the "main" (first) Chamilo portal can login wherever they want
                                    //var_dump($current_access_url_id, $my_url_list); exit;
                                    if (in_array(1, $my_url_list)) { //Check if this admin have the access_url_id = 1 which means the principal
                                        $_user['user_id'] = $uData['user_id'];
                                        api_session_register('_user');
                                        event_login();
                                    } else {
                                        //This means a secondary admin wants to login so we check as he's a normal user
                                        if (in_array($current_access_url_id, $my_url_list)) {
                                            $_user['user_id'] = $uData['user_id'];
                                            api_session_register('_user');
                                            event_login();
                                        } else {
                                            $loginFailed = true;
                                            api_session_unregister('_uid');
                                            header('Location: '.api_get_path(WEB_PATH).'index.php?loginFailed=1&error=access_url_inactive');
                                            exit;
                                        }
                                    }
                                }
                            } else {
                                $_user['user_id'] = $uData['user_id'];
                                api_session_register('_user');
                                event_login();
                            }
                        } else {
                            $loginFailed = true;
                            api_session_unregister('_uid');
                            header('Location: '.api_get_path(WEB_PATH).'index.php?loginFailed=1&error=account_expired');
                            exit;
                        }
                    } else {
                        $loginFailed = true;
                        api_session_unregister('_uid');
                        header('Location: '.api_get_path(WEB_PATH).'index.php?loginFailed=1&error=account_inactive');
                        exit;
                    }
                } else {
                    // login failed: username or password incorrect
                    $loginFailed = true;
                    api_session_unregister('_uid');
                    header('Location: '.api_get_path(WEB_PATH).'index.php?loginFailed=1&error=user_password_incorrect');
                    exit;
                }

                if (isset($uData['creator_id']) && $_user['user_id'] != $uData['creator_id']) {
                    //first login for a not self registred
                    //e.g. registered by a teacher
                    //do nothing (code may be added later)
                }
            } elseif (!empty($extAuthSource[$uData['auth_source']]['login']) && file_exists($extAuthSource[$uData['auth_source']]['login'])) {
                 /*
                  * Process external authentication
                  * on the basis of the given login name
                  */
                 $loginFailed = true;  // Default initialisation. It could
                                       // change after the external authentication
                 $key = $uData['auth_source']; //'ldap','shibboleth'...
                /* >>>>>>>> External authentication modules <<<<<<<<< */
                // see configuration.php to define these
                include_once($extAuthSource[$key]['login']);
                /* >>>>>>>> External authentication modules <<<<<<<<< */
            } else { // no standard Chamilo login - try external authentification
                //huh... nothing to do... we shouldn't get here
                error_log('Chamilo Authentication file '. $extAuthSource[$uData['auth_source']]['login']. ' could not be found - this might prevent your system from doing the corresponding authentication process',0);
            }
            if (!empty($_SESSION['request_uri'])) {
                  $req = $_SESSION['request_uri'];
                  unset($_SESSION['request_uri']);
                  header('location: '.$req);
            } else {
                if (isset($param)) {
                    header('location: '.api_get_path(WEB_PATH).api_get_setting('page_after_login').$param);
                } else {
                    // here is the main redirect of a *normal* login page in Chamilo
                    header('location: '.api_get_path(WEB_PATH).api_get_setting('page_after_login'));
                }
            }
        } else {
            // login failed, Database::num_rows($result) <= 0
            $loginFailed = true;  // Default initialisation. It could
                                  // change after the external authentication

            /*
             * In this section:
             * there is no entry for the $login user in the Chamilo
             * database. This also means there is no auth_source for the user.
             * We let all external procedures attempt to add him/her
             * to the system.
             *
             * Process external login on the basis
             * of the authentication source list
             * provided by the configuration settings.
             * If the login succeeds, for going further,
             * Chamilo needs the $_user['user_id'] variable to be
             * set and registered in the session. It's the
             * responsability of the external login script
             * to provide this $_user['user_id'].
             */

            if (isset($extAuthSource) && is_array($extAuthSource)) {
                foreach($extAuthSource as $thisAuthSource) {
                    if (!empty($thisAuthSource['newUser']) && file_exists($thisAuthSource['newUser'])) {
                        include_once($thisAuthSource['newUser']);
                    } else {
                        error_log('Chamilo Authentication file '. $thisAuthSource['newUser']. ' could not be found - this might prevent your system from using the authentication process in the user creation process',0);
                    }
                }
            } //end if is_array($extAuthSource)
        } //end else login failed
    } elseif (api_get_setting('sso_authentication')==='true' &&  !in_array('webservices', explode('/', $_SERVER['REQUEST_URI']))) {
        /**
         * TODO:
         * - Work on a better validation for webservices paths. Current is very poor and exit
        */
        $subsso = api_get_setting('sso_authentication_subclass');
        require_once(api_get_path(SYS_CODE_PATH).'auth/sso/sso.class.php');
        if (!empty($subsso)) {
            require_once(api_get_path(SYS_CODE_PATH).'auth/sso/sso.'.$subsso.'.class.php');
            $subsso = 'sso'.$subsso;
            $osso = new $subsso(); //load the subclass
        } else {
            $osso = new sso();
        }
        if (isset($_SESSION['_user']['user_id'])) {
            if ($logout) {
                // Library needed by index.php
                include_once api_get_path(LIBRARY_PATH) . 'online.inc.php';
                include_once (api_get_path(LIBRARY_PATH).'course.lib.php');
                // Prevent index.php to redirect
                global $logout_no_redirect;
                $logout_no_redirect = TRUE;
                // Make custom redirect after logout
                online_logout();
                $osso->logout(); //redirects and exits
            }
        } elseif(!$logout) {
            // Handle cookie comming from Master Server
            if (!isset($_GET['sso_referer']) && !isset($_GET['loginFailed'])) {
                // Redirect to master server
                $osso->ask_master();
            } elseif (isset($_GET['sso_cookie'])) {
                $protocol = api_get_setting('sso_authentication_protocol');
                $master_url = api_get_setting('sso_authentication_domain').api_get_setting('sso_authentication_auth_uri');
                if (isset($_GET['sso_referer']) ? $_GET['sso_referer'] === $protocol.$master_url  : FALSE) {
                    //make all the process of checking 
                    //if the user exists (delegated to the sso class)
                    $osso->check_user();
                } else {
                    //Request comes from unknown source
                    $loginFailed = true;
                    api_session_unregister('_uid');
                    header('Location: '.api_get_path(WEB_PATH).'index.php?loginFailed=1&error=unrecognize_sso_origin');
                    exit;
                }
            }
        }//end logout
    } elseif (api_get_setting('openid_authentication')=='true') {
        if (!empty($_POST['openid_url'])) {
            include('main/auth/openid/login.php');
            openid_begin(trim($_POST['openid_url']),api_get_path(WEB_PATH).'index.php');
            //this last function should trigger a redirect, so we can die here safely
            die('Openid login redirection should be in progress');
        } elseif (!empty($_GET['openid_identity'])) {
            //it's usual for PHP to replace '.' (dot) by '_' (underscore) in URL parameters
            include('main/auth/openid/login.php');
            $res = openid_complete($_GET);
            if ($res['status'] == 'success') {
                $id1 = Database::escape_string($res['openid.identity']);
                //have another id with or without the final '/'
                $id2 = (substr($id1,-1,1)=='/'?substr($id1,0,-1):$id1.'/');
                //lookup the user in the main database
                $user_table = Database::get_main_table(TABLE_MAIN_USER);
                $sql = "SELECT user_id, username, password, auth_source, active, expiration_date
                        FROM $user_table
                        WHERE openid = '$id1'
                        OR openid = '$id2' ";
                $result = Database::query($sql);
                if ($result !== false) {
                    if (Database::num_rows($result)>0) {
                        //$row = Database::fetch_array($res);
                        $uData = Database::fetch_array($result);

                        if ($uData['auth_source'] == PLATFORM_AUTH_SOURCE) {
                            //the authentification of this user is managed by Chamilo itself

                            // check if the account is active (not locked)
                            if ($uData['active']=='1') {
                                // check if the expiration date has not been reached
                                if ($uData['expiration_date']>date('Y-m-d H:i:s') OR $uData['expiration_date']=='0000-00-00 00:00:00') {
                                    $_user['user_id'] = $uData['user_id'];
                                    api_session_register('_user');
                                    event_login();
                                } else {
                                    $loginFailed = true;
                                    api_session_unregister('_uid');
                                    header('Location: index.php?loginFailed=1&error=account_expired');
                                    exit;
                                }
                            } else {
                                $loginFailed = true;
                                api_session_unregister('_uid');
                                header('Location: index.php?loginFailed=1&error=account_inactive');
                                exit;
                            }
                            if (isset($uData['creator_id']) && $_user['user_id'] != $uData['creator_id']) {
                                //first login for a not self registred
                                //e.g. registered by a teacher
                                //do nothing (code may be added later)
                            }
                        }
                    } else {
                        //Redirect to the subscription form
                        header('Location: '.api_get_path(WEB_CODE_PATH).'auth/inscription.php?username='.$res['openid.sreg.nickname'].'&email='.$res['openid.sreg.email'].'&openid='.$res['openid.identity'].'&openid_msg=idnotfound');
                        //$loginFailed = true;
                    }
                } else {
                    $loginFailed = true;
                }
            } else {
                $loginFailed = true;
            }
        }
    }

    //    else {} => continue as anonymous user
    $uidReset = true;

    //    $cidReset = true;
    //    $gidReset = true;
} // end else

//Now check for anonymous user mode
if (isset($use_anonymous) && $use_anonymous) {
    //if anonymous mode is set, then try to set the current user as anonymous
    //if he doesn't have a login yet
    api_set_anonymous();
} else {
    //if anonymous mode is not set, then check if this user is anonymous. If it
    //is, clean it from being anonymous (make him a nobody :-))
    api_clear_anonymous();
}

// if there is a cDir parameter in the URL (coming from courses/.htaccess redirection)
if (!empty($cDir)) {
    require_once api_get_path(LIBRARY_PATH).'course.lib.php';
    $c = CourseManager::get_course_id_from_path($cDir);
    if ($c) { $cidReq = $c; }
}

// if the requested course is different from the course in session

if (!empty($cidReq) && (!isset($_SESSION['_cid']) or (isset($_SESSION['_cid']) && $cidReq != $_SESSION['_cid']))) {
    $cidReset = true;
    $gidReset = true;    // As groups depend from courses, group id is reset
}

// if the requested group is different from the group in session
$gid = isset($_SESSION['_gid'])?$_SESSION['_gid']:'';
if ($gidReq && $gidReq != $gid) {
    $gidReset = true;
}


/* USER INIT */

if (isset($uidReset) && $uidReset) {    // session data refresh requested
    $is_platformAdmin = false; $is_allowedCreateCourse = false;

    if (isset($_user['user_id']) && $_user['user_id']) // a uid is given (log in succeeded)
    {
        $user_table = Database::get_main_table(TABLE_MAIN_USER);
        $admin_table = Database::get_main_table(TABLE_MAIN_ADMIN);
       
        $sql = "SELECT user.*, a.user_id is_admin, UNIX_TIMESTAMP(login.login_date) login_date
                 FROM $user_table
                 LEFT JOIN $admin_table a
                 ON user.user_id = a.user_id
                 LEFT JOIN ".$_configuration['statistics_database'].".track_e_login login
                 ON user.user_id  = login.login_user_id
                 WHERE user.user_id = '".$_user['user_id']."'
                 ORDER BY login.login_date DESC LIMIT 1";    

        $result = Database::query($sql);

        if (Database::num_rows($result) > 0) {
            // Extracting the user data

            $uData = Database::fetch_array($result);

            $_user ['firstName']         = $uData ['firstname' ];
            $_user ['lastName' ]         = $uData ['lastname'  ];
            $_user ['mail'     ]         = $uData ['email'     ];
            $_user ['lastLogin']         = $uData ['login_date'];
            $_user ['official_code']    = $uData ['official_code'];
            $_user ['picture_uri']         = $uData ['picture_uri'];
            $_user ['user_id']             = $uData ['user_id'];
            $_user ['language']            = $uData ['language'];
            $_user ['auth_source']         = $uData ['auth_source'];
            $_user ['theme']            = $uData ['theme'];
            $_user ['status']            = $uData ['status'];

            $is_platformAdmin        = (bool) (! is_null( $uData['is_admin']));
            $is_allowedCreateCourse  = (bool) (($uData ['status'] == 1) or (api_get_setting('drhCourseManagerRights') and $uData['status'] == 4));

            api_session_register('_user');
        } else {
            header('location:'.api_get_path(WEB_PATH));
            //exit("WARNING UNDEFINED UID !! ");
        }
    } else { // no uid => logout or Anonymous
        api_session_unregister('_user');
        api_session_unregister('_uid');
    }

    api_session_register('is_platformAdmin');
    api_session_register('is_allowedCreateCourse');
} else { // continue with the previous values
    $_user = $_SESSION['_user'];
    $is_platformAdmin = $_SESSION['is_platformAdmin'];
    $is_allowedCreateCourse = $_SESSION['is_allowedCreateCourse'];
}

/*  COURSE INIT */

if (isset($cidReset) && $cidReset) { // course session data refresh requested or empty data
    
    if ($cidReq) {
        $course_table = Database::get_main_table(TABLE_MAIN_COURSE);
        $course_cat_table = Database::get_main_table(TABLE_MAIN_CATEGORY);
        $sql =  "SELECT course.*, course_category.code faCode, course_category.name faName
                 FROM $course_table
                 LEFT JOIN $course_cat_table
                 ON course.category_code = course_category.code
                 WHERE course.code = '$cidReq'";
        $result = Database::query($sql);

        if (Database::num_rows($result)>0) {
            $course_data = Database::fetch_array($result);
            //@TODO real_cid should be cid, for working with numeric course id
            $_real_cid                      = $course_data['id'];

            $_cid                           = $course_data['code'];
            $_course = array();
            $_course['real_id']             = $course_data['id'];
            $_course['id']                  = $course_data['code']; //auto-assigned integer
            $_course['code']                = $course_data['code']; 
            $_course['name']                = $course_data['title'];
            $_course['official_code']       = $course_data['visual_code']; // use in echo
            $_course['sysCode']             = $course_data['code']; // use as key in db
            $_course['path']                = $course_data['directory']; // use as key in path
            $_course['dbName']              = $course_data['db_name']; // use as key in db list
            $_course['db_name']             = $course_data['db_name']; // 
            $_course['dbNameGlu']           = $_configuration['table_prefix'] . $course_data['db_name'] . $_configuration['db_glue']; // use in all queries
            $_course['titular']             = $course_data['tutor_name'];
            $_course['language']            = $course_data['course_language'];
            $_course['extLink']['url' ]     = $course_data['department_url'];
            $_course['extLink']['name']     = $course_data['department_name'];
            $_course['categoryCode']        = $course_data['faCode'];
            $_course['categoryName']        = $course_data['faName'];
            $_course['visibility']          = $course_data['visibility'];
            $_course['subscribe_allowed']   = $course_data['subscribe'];
            $_course['unubscribe_allowed']  = $course_data['unsubscribe'];

            api_session_register('_cid');
            api_session_register('_course');
            //@TODO real_cid should be cid, for working with numeric course id
            api_session_register('_real_cid');

            // if a session id has been given in url, we store the session
            if (api_get_setting('use_session_mode')=='true') {
                // Database Table Definitions
                $tbl_session                 = Database::get_main_table(TABLE_MAIN_SESSION);
                $tbl_user                     = Database::get_main_table(TABLE_MAIN_USER);
                $tbl_session_course         = Database::get_main_table(TABLE_MAIN_SESSION_COURSE);
                $tbl_session_course_user     = Database::get_main_table(TABLE_MAIN_SESSION_COURSE_USER);

                if (!empty($_GET['id_session'])) {
                    $_SESSION['id_session'] = intval($_GET['id_session']);
                    $sql = 'SELECT name FROM '.$tbl_session . ' WHERE id="'.intval($_SESSION['id_session']) . '"';
                    $rs = Database::query($sql);
                    list($_SESSION['session_name']) = Database::fetch_array($rs);
                } else {
                    api_session_unregister('session_name');
                    api_session_unregister('id_session');
                }
            }

            if (!isset($_SESSION['login_as'])) {
                //We add a new record in the course tracking table
                $course_tracking_table = Database :: get_statistic_table(TABLE_STATISTIC_TRACK_E_COURSE_ACCESS);
                $time = api_get_datetime();
                $sql="INSERT INTO $course_tracking_table(course_code, user_id, login_course_date, logout_course_date, counter, session_id)" .
                     "VALUES('".$_course['sysCode']."', '".$_user['user_id']."', '$time', '$time', '1', '".api_get_session_id()."')";
                //error_log($sql);
                Database::query($sql);
            }
        } else {
            //exit("WARNING UNDEFINED CID !! ");
            header('location:'.api_get_path(WEB_PATH));
        }
    } else {
        api_session_unregister('_cid');
        api_session_unregister('_real_cid');
        api_session_unregister('_course');
        
        if (!empty($_SESSION)) {
                foreach($_SESSION as $key=>$session_item) {
                if (strpos($key,'lp_autolunch_') === false) {
                    continue;               
                } else {
                    if(isset($_SESSION[$key])) {
                        api_session_unregister($key);   
                    }
                }
            }   
        }             
        //Deleting session info 
        if (api_get_session_id()) {                
            api_session_unregister('id_session');
            api_session_unregister('session_name');
        }   
    }
} else { // continue with the previous values
    if (empty($_SESSION['_course']) OR empty($_SESSION['_cid'])) { //no previous values...
        $_cid         = -1;        //set default values that will be caracteristic of being unset
        $_course     = -1;
    } else {
        $_cid         = $_SESSION['_cid'   ];
           $_course    = $_SESSION['_course'];

           // these lines are usefull for tracking. Indeed we can have lost the id_session and not the cid.
           // Moreover, if we want to track a course with another session it can be usefull        
        if (!empty($_GET['id_session'])) {
            $tbl_session                 = Database::get_main_table(TABLE_MAIN_SESSION);
            $_SESSION['id_session']        = intval($_GET['id_session']);
            $sql = 'SELECT name FROM '.$tbl_session . ' WHERE id="'.intval($_SESSION['id_session']). '"';
            $rs = Database::query($sql);
            list($_SESSION['session_name']) = Database::fetch_array($rs);
        }

        if (!isset($_SESSION['login_as'])) {

            $course_tracking_table = Database :: get_statistic_table(TABLE_STATISTIC_TRACK_E_COURSE_ACCESS);
               if (isset($_configuration['session_lifetime'])) {
                   $session_lifetime    = $_configuration['session_lifetime'];
            } else {
                $session_lifetime    = 3600;
              }

            $course_code=$_course['sysCode'];
            $time = api_get_datetime();

            //We select the last record for the current course in the course tracking table
            // But only if the login date is < thant now + max_life_time
            
            $sql="SELECT course_access_id FROM $course_tracking_table
                  WHERE user_id=".intval($_user ['user_id'])."
                        AND course_code='$course_code' AND session_id = ".api_get_session_id()."
                        AND login_course_date > now() - INTERVAL $session_lifetime SECOND
                        ORDER BY login_course_date DESC LIMIT 0,1";
                $result=Database::query($sql);
                //error_log($sql);
            if (Database::num_rows($result)>0) {

                $i_course_access_id = Database::result($result,0,0);
                //We update the course tracking table
                $sql="UPDATE $course_tracking_table  SET logout_course_date = '$time', counter = counter+1 ".
                     "WHERE course_access_id=".intval($i_course_access_id)." AND session_id = ".api_get_session_id();
                //error_log($sql);
                Database::query($sql);
            } else {
                $sql="INSERT INTO $course_tracking_table (course_code, user_id, login_course_date, logout_course_date, counter, session_id)" .
                     "VALUES('".$course_code."', '".$_user['user_id']."', '$time', '$time', '1','".api_get_session_id()."')";
                //error_log($sql);
                Database::query($sql);
            }
            }
    }
}

/*  COURSE / USER REL. INIT */

if ((isset($uidReset) && $uidReset) || (isset($cidReset) && $cidReset)) { // session data refresh requested
    if (isset($_user['user_id']) && $_user['user_id'] && isset($_cid) && $_cid) { // have keys to search data
        if (api_get_setting('use_session_mode') != 'true') {

            $course_user_table = Database::get_main_table(TABLE_MAIN_COURSE_USER);
            $sql = "SELECT * FROM $course_user_table
                   WHERE user_id  = '".$_user['user_id']."' AND relation_type<>".COURSE_RELATION_TYPE_RRHH."
                   AND course_code = '$cidReq'";

            $result = Database::query($sql);

            if (Database::num_rows($result) > 0) { // this  user have a recorded state for this course
                $cuData = Database::fetch_array($result);

                $is_courseMember     = true;
                $is_courseTutor      = (bool) ($cuData['tutor_id' ] == 1 );
                $is_courseAdmin      = (bool) ($cuData['status'] == 1 );

                api_session_register('_courseUser');
            } else { // this user has no status related to this course
                $is_courseMember = false;
                $is_courseAdmin  = false;
                $is_courseTutor  = false;
            }

            $is_courseAdmin = (bool) ($is_courseAdmin || $is_platformAdmin);

        } else {

            $tbl_course_user = Database :: get_main_table(TABLE_MAIN_COURSE_USER);

             $sql = "SELECT * FROM ".$tbl_course_user."
               WHERE user_id  = '".$_user['user_id']."' AND relation_type<>".COURSE_RELATION_TYPE_RRHH."
               AND course_code = '$cidReq'";

            $result = Database::query($sql);

            if (Database::num_rows($result) > 0) { // this  user have a recorded state for this course
                $cuData = Database::fetch_array($result);

                $_courseUser['role'] = $cuData['role'  ];
                $is_courseMember     = true;
                $is_courseTutor      = (bool) ($cuData['tutor_id' ] == 1 );
                $is_courseAdmin      = (bool) ($cuData['status'] == 1 );

                api_session_register('_courseUser');
            }
            if (!isset($is_courseAdmin)) { // this user has no status related to this course
                // is it the session coach or the session admin ?

                $tbl_session = Database :: get_main_table(TABLE_MAIN_SESSION);
                $tbl_session_course = Database :: get_main_table(TABLE_MAIN_SESSION_COURSE);
                $tbl_session_course_user = Database :: get_main_table(TABLE_MAIN_SESSION_COURSE_USER);


                $sql = " SELECT session.id_coach, session_admin_id FROM $tbl_session session,$tbl_session_course_user session_rcru
                        WHERE session_rcru.id_session = session.id AND session_rcru.course_code = '$_cid' AND session_rcru.id_user='{$_user['user_id']}' AND session_rcru.status = 2";

                /*$sql = "SELECT session.id_coach, session_admin_id
                        FROM ".$tbl_session." as session
                        INNER JOIN ".$tbl_session_course_user."
                            ON session_rel_course.id_session = session.id
                            AND session_rel_course.course_code='$_cid'";
                */

                $result = Database::query($sql);
                $row = Database::store_result($result);

                if ($row[0]['id_coach']==$_user['user_id']) {
                    $_courseUser['role'] = 'Professor';
                    $is_courseMember     = true;
                    $is_courseTutor      = true;
                    $is_courseCoach      = true;
                    $is_sessionAdmin     = false;

                    if (api_get_setting('extend_rights_for_coach')=='true') {
                        $is_courseAdmin = true;
                    } else {
                        $is_courseAdmin = false;
                    }

                    api_session_register('_courseUser');
                } elseif ($row[0]['session_admin_id']==$_user['user_id']) {
                    $_courseUser['role'] = 'Professor';
                    $is_courseMember     = false;
                    $is_courseTutor      = false;
                    $is_courseAdmin      = false;
                    $is_courseCoach      = false;
                    $is_sessionAdmin     = true;
                } else {
                    // Check if the current user is the course coach
                    $sql = "SELECT 1
                            FROM ".$tbl_session_course_user."
                            WHERE course_code='$_cid'
                            AND id_user = '".$_user['user_id']."'
                            AND id_session = '".api_get_session_id()."'
                            AND status = 2";

                    $result = Database::query($sql);
                    if ($row = Database::fetch_array($result)) {
                        $_courseUser['role'] = 'Professor';
                        $is_courseMember     = true;
                        $is_courseTutor      = true;
                        $is_courseCoach      = true;
                        $is_sessionAdmin     = false;

                        if (api_get_setting('extend_rights_for_coach')=='true') {
                            $is_courseAdmin = true;
                        } else {
                            $is_courseAdmin = false;
                        }
                        api_session_register('_courseUser');
                    } else {
                        if (api_get_session_id() != 0) {
                            // Check if the user is a student is this session
                            $sql = "SELECT * FROM ".$tbl_session_course_user."
                                    WHERE id_user  = '".$_user['user_id']."'
                                    AND id_session = '".api_get_session_id()."'
                                    AND course_code = '$cidReq' AND status NOT IN(2)";
                            $result = Database::query($sql);
                            if (Database::num_rows($result) > 0) { // this  user have a recorded state for this course
                                while($row = Database::fetch_array($result)){
                                    $is_courseMember     = true;
                                    $is_courseTutor      = false;
                                    $is_courseAdmin      = false;
                                    $is_sessionAdmin     = false;
                                    api_session_register('_courseUser');
                                }
                            }
                        } else {
                            //unregister user
                            $is_courseMember     = false;
                            $is_courseTutor      = false;
                            $is_courseAdmin      = false;
                            $is_sessionAdmin     = false;
                            api_session_unregister('_courseUser');
                            //$_course['visibility'] = 0; this depends the
                        }

                    }
                }
            }
        }
    } else { // keys missing => not anymore in the course - user relation
        // course
        $is_courseMember = false;
        $is_courseAdmin  = false;
        $is_courseTutor  = false;
        $is_courseCoach  = false;
        $is_sessionAdmin     = false;
        api_session_unregister('_courseUser');
    }

    //DEPRECATED
    //$is_courseAllowed=($_cid && ($_course['visibility'] || $is_courseMember || $is_platformAdmin))?true:false;

    //NEW
    if (isset($_course)) {
        if ($_course['visibility'] == COURSE_VISIBILITY_OPEN_WORLD)
            $is_allowed_in_course = true;
        elseif ($_course['visibility'] == COURSE_VISIBILITY_OPEN_PLATFORM && isset($_user['user_id']) && !api_is_anonymous($_user['user_id']))
            $is_allowed_in_course = true;
        elseif ($_course['visibility'] == COURSE_VISIBILITY_REGISTERED && ($is_platformAdmin || $is_courseMember))
            $is_allowed_in_course = true;
        elseif ($_course['visibility'] == COURSE_VISIBILITY_CLOSED && ($is_platformAdmin || $is_courseAdmin))
            $is_allowed_in_course = true;
        else $is_allowed_in_course = false;
    }

    // requires testing!!!
    // check the session visibility
    if (!empty($is_allowed_in_course)) {        
        $my_session_id = api_get_session_id();
        //if I'm in a session
        //var_dump($is_platformAdmin, $is_courseTutor,api_is_coach());
        if ($my_session_id!=0)
            if (!$is_platformAdmin) {
                // admin and session coach are *not* affected to the invisible session mode
                // the coach is not affected because he can log in some days after the end date of a session
                $session_visibility = api_get_session_visibility($my_session_id);
                if ($session_visibility==SESSION_INVISIBLE)
                    $is_allowed_in_course =false;
            }

    }

    // save the states

    api_session_register('is_courseMember');
    api_session_register('is_courseAdmin');
    //api_session_register('is_courseAllowed'); //deprecated old permission var
    api_session_register('is_courseTutor');
    api_session_register('is_allowed_in_course'); //new permission var
    api_session_register('is_courseCoach');
    api_session_register('is_sessionAdmin');
} else { // continue with the previous values

    if (isset($_SESSION ['_courseUser'])) {
        $_courseUser          = $_SESSION ['_courseUser'];
    }

    $is_courseMember      = $_SESSION ['is_courseMember' ];
    $is_courseAdmin       = $_SESSION ['is_courseAdmin'  ];
    //$is_courseAllowed     = $_SESSION ['is_courseAllowed']; //deprecated
    $is_allowed_in_course = $_SESSION ['is_allowed_in_course'];
    $is_courseTutor       = $_SESSION ['is_courseTutor'  ];
    $is_courseCoach       = $_SESSION ['is_courseCoach'  ];
}

/*  GROUP INIT */

if ((isset($gidReset) && $gidReset) || (isset($cidReset) && $cidReset)) { // session data refresh requested
    if ($gidReq && $_cid ) { // have keys to search data
        $group_table = Database::get_course_table(TABLE_GROUP);
        $sql = "SELECT * FROM $group_table WHERE id = '$gidReq'";
        $result = Database::query($sql);
        if (Database::num_rows($result) > 0) { // This group has recorded status related to this course
            $gpData = Database::fetch_array($result);
            $_gid                   = $gpData ['id'             ];
            api_session_register('_gid');
        } else {
            exit("WARNING UNDEFINED GID !! ");
        }
    } elseif (isset($_SESSION['_gid']) or isset($_gid)) { // Keys missing => not anymore in the group - course relation
        api_session_unregister('_gid');
    }
} elseif (isset($_SESSION['_gid'])) { // continue with the previous values
    $_gid             = $_SESSION ['_gid'            ];
} else { //if no previous value, assign caracteristic undefined value
    $_gid = -1;
}
//set variable according to student_view_enabled choices
if (api_get_setting('student_view_enabled') == "true") {
    if (isset($_GET['isStudentView'])) {
        if ($_GET['isStudentView'] == 'true') {
            if (isset($_SESSION['studentview'])) {
                if (!empty($_SESSION['studentview'])) {
                    // switching to studentview
                    $_SESSION['studentview'] = 'studentview';
                }
            }
        } elseif ($_GET['isStudentView'] == 'false') {
            if (isset($_SESSION['studentview'])) {
                if (!empty($_SESSION['studentview'])) {
                    // switching to teacherview
                    $_SESSION['studentview'] = 'teacherview';
                }
            }
        }
    } elseif (!empty($_SESSION['studentview'])) {
        //all is fine, no change to that, obviously
    } elseif (empty($_SESSION['studentview'])) {
        // We are in teacherview here
        $_SESSION['studentview'] = 'teacherview';
    }
}

if (isset($_cid)) {
    $tbl_course = Database::get_main_table(TABLE_MAIN_COURSE);
    $time = api_get_datetime();
    $sql="UPDATE $tbl_course SET last_visit= '$time' WHERE code='$_cid'";
    Database::query($sql);
}