<?php
require_once("$CFG->dirroot/enrol/enrol.class.php");

// The following flags are set in the configuration
// $CFG->enrol_flatfilelocation:       where is the file we are looking for?
// $CFG->enrol_allowinternal:          allow internal enrolment in courses
// $CFG->enrol_emailstudents:          send email to students when they are enrolled in a course
// $CFG->enrol_emailteachers:          send email to teachers when they are enrolled in a course
// $CFG->enrol_emailadmins:            email the log from the cron job to the admin


class enrolment_plugin extends enrolment_base {

    var $log;    

/// Override the base print_entry() function
function print_entry($course) {
    global $CFG;

    if (! empty($CFG->enrol_allowinternal) ) {
        parent::print_entry($course);
    } else {
        print_header();
        notice(get_string("enrolmentnointernal"), $CFG->wwwroot);
    }
}


/// Override the base check_entry() function
function check_entry($form, $course) {
    global $CFG;

    if (! empty($CFG->enrol_allowinternal) ) {
        parent::check_entry($form, $course);
    }
}


/// Override the base config_form() function
function config_form($frm) {
    global $CFG;
    include ("$CFG->dirroot/enrol/flatfile/config.html");    
}


/// Override the base process_config() function
function process_config($config) {

    if (!isset($config->enrol_flatfilelocation)) {
        $config->enrol_flatfilelocation = '';
    }
    set_config('enrol_flatfilelocation', $config->enrol_flatfilelocation);

    if (!isset($config->enrol_mailstudents)) {
        $config->enrol_mailstudents = '';
    }
    set_config('enrol_mailstudents', $config->enrol_mailstudents);

    if (!isset($config->enrol_mailteachers)) {
        $config->enrol_mailteachers = '';
    }
    set_config('enrol_mailteachers', $config->enrol_mailteachers);

    if (!isset($config->enrol_mailadmins)) {
        $config->enrol_mailadmins = '';
    }
    set_config('enrol_mailadmins', $config->enrol_mailadmins);

    if (!isset($config->enrol_allowinternal)) {
        $config->enrol_allowinternal = '';
    }
    set_config('enrol_allowinternal', $config->enrol_allowinternal);
    
    return true;

}

/**
* Override the base cron() function to read in a file
*
* Comma separated file assumed to have four or six fields per line:
*   operation, role, idnumber(user), idnumber(course) [, starttime, endtime]
* where:
*   operation        = add | del
*   role             = student | teacher | teacheredit
*   idnumber(user)   = idnumber in the user table NB not id
*   idnumber(course) = idnumber in the course table NB not id
*   starttime        = start time (in seconds since epoch) - optional
*   endtime          = end time (in seconds since epoch) - optional
*/
    function cron() {
        global $CFG;

        /// call the base class
        parent::cron();

        if (empty($CFG->enrol_flatfilelocation)) {
            $filename = "$CFG->dataroot/1/enrolments.txt";  // Default location
        } else {
            $filename = $CFG->enrol_flatfilelocation;
        }

        if ( file_exists($filename) ) {
            
            $this->log  = userdate(time()) . "\n";
            $this->log .= "Flatfile enrol cron found file: $filename\n\n";

            if (($fh = fopen($filename, "r")) != false) {
            
                $line = 0;
                while (!feof($fh)) {
                
                    $line++;
                    $fields = explode( ",", str_replace( "\r", "", fgets($fh) ) );


                /// If a line is incorrectly formatted ie does not have 4 comma separated fields then ignore it
                    if (count($fields) != 4 and count($fields) !=6) {
                        if ( count($fields) > 1 or strlen($fields[0]) > 1) { // no error for blank lines
                            $this->log .= "$line: Line incorrectly formatted - ignoring\n";
                        }
                        continue;
                    }
                    

                    $fields[0] = trim(strtolower($fields[0]));
                    $fields[1] = trim(strtolower($fields[1]));
                    $fields[2] = trim($fields[2]);
                    $fields[3] = trim($fields[3]);
                    
                    $this->log .= "$line: $fields[0] $fields[1] $fields[2] $fields[3] ";
                    
                    if (!empty($fields[5])) {
                        $fields[4] = (int)trim($fields[4]);
                        $fields[5] = (int)trim($fields[5]);
                        $this->log .= "$fields[4] $fields[5]";
                    } else {
                        $fields[4] = 0;
                        $fields[5] = 0;
                    } 

                    $this->log .= ":";


                /// check correct formatting of operation field
                    if ($fields[0] != "add" and $fields[0] != "del") {
                        $this->log .= "Unknown operation in field 1 - ignoring line\n";
                        continue;
                    }


                /// check correct formatting of role field
                    if ($fields[1] != "student" and $fields[1] != "teacher" and $fields[1] != "teacheredit") {
                        $this->log .= "Unknown role in field2 - ignoring line\n";
                        continue;
                    }


                    if (! $user = get_record("user", "idnumber", $fields[2]) ) {
                        $this->log .= "Unknown user idnumber in field 3 - ignoring line\n";
                        continue;
                    }


                    if (! $course = get_record("course", "idnumber", $fields[3]) ) {
                        $this->log .= "Unknown course idnumber in field 4 - ignoring line\n";
                        continue;
                    }

                    if ($fields[4] > $fields[5]) {
                        $this->log .= "Start time was later than end time - ignoring line\n";
                        continue;
                    }


                    unset($elog);
                    switch ($fields[1]) {
                        case "student":
                            if ($fields[0] == "add") {
                                if (! enrol_student($user->id, $course->id, $fields[4], $fields[5])) {
                                    $elog = "Error enrolling in course\n";
                                }
                            } else {
                                if (! unenrol_student($user->id, $course->id)) {
                                    $elog = "Error unenrolling from course\n";
                                }
                            }
                            break;

                        case "teacher":
                            if ($fields[0] == "add") {
                                if (! add_teacher($user->id, $course->id, 0, '', $fields[4], $fields[5])) {
                                    $elog = "Error adding teacher to course\n";
                                }
                            } else {
                                if (! remove_teacher($user->id, $course->id)) {
                                    $elog = "Error removing teacher from course\n";
                                }
                            }
                            break;

                        case "teacheredit":
                            if ($fields[0] == "add") {
                                if (! add_teacher($user->id, $course->id, 1, '', $fields[4], $fields[5])) {
                                    $elog = "Error adding teacher to course\n";
                                }
                            } else {
                                if (! remove_teacher($user->id, $course->id)) {
                                    $elog = "Error removing teacher from course\n";
                                }
                            }
                            break;

                        default: // should never get here as checks made above for correct values of $fields[1]

                    } // end of switch


                    if ( empty($elog) and ($fields[0] == "add") ) {
   
                        if ($fields[1] == "student") {
                            if (! $teacher = get_teacher($course->id)) {
                                $teacher = get_admin();
                            }
                        } else {
                            $teacher = get_admin();
                        }

                        if (!empty($CFG->enrol_mailstudents)) {
                            $a->coursename = "$course->fullname";
                            $a->profileurl = "$CFG->wwwroot/user/view.php?id=$user->id&amp;course=$course->id";
                            email_to_user($user, $teacher, get_string("enrolmentnew", '', $course->shortname), 
                                          get_string('welcometocoursetext', '', $a));
                        }

                        if (!empty($CFG->enrol_mailteachers)) {
                            $a->course = "$course->fullname";
                            $a->user = fullname($user);
                            email_to_user($teacher, $user, get_string("enrolmentnew", '', $course->shortname), 
                                          get_string('enrolmentnewuser', '', $a));
                        }
                    }


                    if (empty($elog)) {
                        $elog = "OK\n";
                    }
                    $this->log .= $elog;

                } // end of while loop

            fclose($fh);
            } // end of if(file_open)

            if(! @unlink($filename)) {
                email_to_user(get_admin(), get_admin(), get_string("filelockedmailsubject", "enrol_flatfile"), get_string("filelockedmail", "enrol_flatfile", $filename));
                $this->log .= "Error unlinking file $filename\n";
            }

            if (!empty($CFG->enrol_mailadmins)) {
                email_to_user(get_admin(), get_admin(), "Flatfile Enrolment Log", $this->log);
            }

        } // end of if(file_exists)

    } // end of function

} // end of class

?>