moodle_local_treestudyplan/classes/enrolcohortsync.php

<?php
namespace local_treestudyplan;
require_once($CFG->libdir.'/externallib.php');

use \local_treestudyplan\studyplan;

class enrolcohortsync {
    private const METHOD = "cohort";
    private $studyplan;

    function __construct($studyplan){
        $this->studyplan = $studyplan;
        $this->studyplanid = $studyplan->id();
    }

    static private function array_remove_value(&$array,$value){
        while (($key = array_search($value, $array)) !== false) {
            unset($array[$key]);
        }
    }

    function sync(){
        global $DB;
        // TODO: Determine if it would be better to add a database table of our own to store references between studyplan and cohort sync enrolment
        // instead of using customtext4 for this


        if(get_config("local_treestudyplan","csync_enable")){
            $enrol = enrol_get_plugin(self::METHOD);
            // Find the courses that need to be synced to the associated cohorts
            $courseids = $this->studyplan->get_linked_course_ids();

            // And find the cohorts that are linked to this studyplan.
            $cohortids = $this->studyplan->get_linked_cohort_ids();

            // Next, for each course that is linked:
            foreach($courseids as $courseid){
                $course = get_course($courseid);
                // first create any nonexistent links
                foreach($cohortids as $cohortid){
                    $cohort = $DB->get_record('cohort',['id'=>$cohortid]);


                    $instanceparams = [
                        'courseid' => $courseid,
                        'customint1' => $cohortid,
                        'enrol' => self::METHOD,
                        'roleid' => get_config("local_treestudyplan","csync_roleid"),
                    ];

                    $instancenewparams = [
                        'customint1' => $cohortid,
                        'enrol' => self::METHOD,
                        'roleid' => get_config("local_treestudyplan","csync_roleid"),
                    ];


                    // Create group: 

                    // 1:   check if a link exists
                    //      If not, make it (maybe use some of the custom text to list the studyplans involved)
                    if ($instance = $DB->get_record('enrol', $instanceparams)) {
                        // it already exists
                        // check if this studyplan is already referenced in customtext4 in json format
                        if(empty($instance->customtext4)){
                            // Cohort sync was already done, but without studyplan info
                            // make sure we add a "manual" link to the plan list
                            $plans = ["manual"];
                        }
                        else{
                            $plans = json_decode($instance->customtext4);
                        }
                        if(!$in_array($this->studyplanid ,$plans)){
                            // if not, add it to the reference
                            $plans[] = $this->studyplanid;
                            $enrol->update_instance($instance,["customtext4"=>json_encode($plans)]);
                        }

                    } else {
                        // If method members should be added to a group, create it or get its ID.

                        if (get_config("local_treestudyplan","csync_creategroup")) {
                            // Make or get new new cohort group - but only on creating of instances
                            $groupname = $cohort->name." ".strtolower(get_string('defaultgroupname', 'core'));
                            // and make sure the 
                            $instancenewparams['customint2'] = uploadenrolmentmethods_get_group($courseid, $groupname);
                        }
                        
                        if ($instanceid = $enrol->add_instance($course, $instancenewparams)) {
                            // also record the (as of yet only) studyplans id requiring this association
                            // in the customtext4 field in json format
                            $enrol->update_instance($instance,["customtext4"=>json_encode([$this->studyplanid])]);
                            
                            // Successfully added a valid new instance, so now instantiate it.
                            // First synchronise the enrolment.
                            $cohorttrace = new null_progress_trace();
                            enrol_cohort_sync($cohorttrace, $cohortid);
                            $cohorttrace->finished();
    
                        } else {
                            // Instance not added for some reason, so report an error somewhere
                            // (or not)
                        }
                    } 
                }

                // 2:   Check if there are cohort links for this studyplan in this course that should be removed
                //      A: Check if there are cohort links that are no longer related to this studyplan
                //      B: Check if these links are valid through another studyplan...
                //      If no one uses the link anymore, deactivate it...
                // INFO: This does not remove the sync from courses that are unlinked from a studplan. But maybe we do not want that anyway
                //       since it is generally a good idea to keep student access to courses available 

                if(get_config("local_treestudyplan","csync_autoremove")){
                    // Only try the autoremove if the option is enabled

                    // find all cohort syncs for this course
                    $searchparams = [
                        'courseid' => $courseid,
                        'enrol' => self::METHOD,
                        'roleid' => get_config("local_treestudyplan","csync_roleid"),
                    ];

                    $records = $DB->get_records("enrol",$searchparams);
                    foreach($records as $instance){
                        if(!empty($instance->customtext4)){ // only check the records that have studyplan information in the customtext4 field
                            // first check if the cohort is not one of the cohort id's we have associated
                            if(!in_array($instance->customint1,$cohortids)){
                                // So it may or may not need to be removed
                                $plans = json_decode($instance->customtext4);
                                if($plans !== null && is_array($plans)){
                                    //if a valid array is not returned, better leave it be, we don't want to mess with it
                                    // otherwise, check if we should remove it
                                    if(in_array($this->studyplanid,$plans)){
                                        //if this plan was referenced before
                                        // first remove the link
                                        self::array_remove_value($plans,$this->studyplanid);
                                        if(count($plans) == 0){
                                            // delete the sync if there are no studyplan references left
                                            $enrol->delete_instance($instance);
                                        } else {
                                            // otherwise just update the references so this studyplan is no longer linked
                                            $enrol->update_instance($instance,["customtext4"=>json_encode($plans)]);
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}