<?php
namespace local_treestudyplan;

require_once($CFG->libdir.'/externallib.php');

class studyplan {


    const TABLE = "local_treestudyplan";
    private static $STUDYPLAN_CACHE = [];


    private $r; // Holds database record
    private $id;
    private $aggregator;
    private $context = null; // Hold context object once retrieved
    private $linked_userids = null; // cache lookup of linked users (saves queries)

    public function getAggregator(){ 
        return $this->aggregator;
    }

    // Cache constructors to avoid multiple creation events in one session.
    public static function findById($id): self {
        if(!array_key_exists($id,self::$STUDYPLAN_CACHE)){
            self::$STUDYPLAN_CACHE[$id] = new self($id);
        } 
        return self::$STUDYPLAN_CACHE[$id];
    }

    private function __construct($id) {
        global $DB;
        $this->id = $id;
        $this->r = $DB->get_record(self::TABLE,['id' => $id]);

        $this->aggregator = aggregator::createOrDefault($this->r->aggregation, $this->r->aggregation_config);
    }

    public function id(){
        return $this->id;
    }

    public function shortname(){
        return $this->r->shortname;
    }

    public function slots(){
        return $this->r->slots;
    }

    public function name(){
        return $this->r->name;
    }

    public function startdate(){
        return new \DateTime($this->r->startdate);
    }

    /**
     * Return the context this studyplan is associated to
     */
    public function context(): \context{
        if(!isset($this->context)){
            try{
                $this->context = contextinfo::by_id($this->r->context_id)->context;
            }
            catch(\dml_missing_record_exception $x){
                throw new \InvalidArgumentException("Context {$this->r->context_id} not available"); // Just throw it up again. catch is included here to make sure we know it throws this exception
            }
        }
        return $this->context;
    }

    public function enddate(){
        if($this->r->enddate && strlen($this->r->enddate) > 0){
            return new \DateTime($this->r->enddate);
        }
        else{
            // return a date 100 years into the future
            return (new \DateTime($this->r->startdate))->add(new \DateInterval("P100Y"));
        }

    }

    public static function simple_structure($value=VALUE_REQUIRED){
        return new \external_single_structure([
            "id" => new \external_value(PARAM_INT, 'id of studyplan'),
            "name" => new \external_value(PARAM_TEXT, 'name of studyplan'),
            "shortname"=> new \external_value(PARAM_TEXT, 'shortname of studyplan'),
            "slots" => new \external_value(PARAM_INT, 'number of slots in studyplan'),
            "context_id" => new \external_value(PARAM_INT, 'context_id of studyplan'),
            "description"=> new \external_value(PARAM_TEXT, 'description of studyplan'),
            "startdate" => new \external_value(PARAM_TEXT, 'start date of studyplan'),
            "enddate" => new \external_value(PARAM_TEXT, 'end date of studyplan'),
            "aggregation" => new \external_value(PARAM_TEXT, 'selected aggregator'),
            "aggregation_config" => new \external_value(PARAM_TEXT, 'config string for aggregator'),
            "aggregation_info" => aggregator::basic_structure(),
        ],'Basic studyplan info',$value);
    }

    public function simple_model(){
        return [
            'id' => $this->r->id,
            'name' => $this->r->name,
            'shortname' => $this->r->shortname,
            'slots' => $this->r->slots,
            'context_id' => $this->context()->id,
            'description' => $this->r->description,
            'startdate' => $this->r->startdate,
            'enddate' => $this->r->enddate,
            "aggregation" => $this->r->aggregation,
            "aggregation_config" => $this->aggregator->config_string(),
            'aggregation_info' => $this->aggregator->basic_model(),
        ];
    }

    public static function editor_structure($value=VALUE_REQUIRED){
        return new \external_single_structure([
            "id" => new \external_value(PARAM_INT, 'id of studyplan'),
            "name" => new \external_value(PARAM_TEXT, 'name of studyplan'),
            "shortname"=> new \external_value(PARAM_TEXT, 'shortname of studyplan'),
            "description"=> new \external_value(PARAM_TEXT, 'description of studyplan'),
            "slots" => new \external_value(PARAM_INT, 'number of slots in studyplan'),
            "context_id" => new \external_value(PARAM_INT, 'context_id of studyplan'),
            "startdate" => new \external_value(PARAM_TEXT, 'start date of studyplan'),
            "enddate" => new \external_value(PARAM_TEXT, 'end date of studyplan'),
            "aggregation" => new \external_value(PARAM_TEXT, 'selected aggregator'),
            "aggregation_config" => new \external_value(PARAM_TEXT, 'config string for aggregator'),
            "aggregation_info" => aggregator::basic_structure(),
            /*"association" => new \external_single_structure([
                'cohorts' => new \external_multiple_structure(associationservice::cohort_structure()),
                'users' => new \external_multiple_structure(associationservice::user_structure()),
            ]),*/
            "studylines" => new \external_multiple_structure(studyline::editor_structure()),
            "advanced" => new \external_single_structure([
                "force_scales" => new \external_single_structure([
                    "scales" => new \external_multiple_structure(new \external_single_structure([
                            "id" => new \external_value(PARAM_INT, 'id of scale'),
                            "name" => new \external_value(PARAM_TEXT, 'name of scale'),
                        ])),
                    ],"Scale forcing on stuff", VALUE_OPTIONAL), 
                ],"Advanced features available", VALUE_OPTIONAL),
            ],'Studyplan full structure',$value);
    }

    public function editor_model(){
        global $DB;

        $model = [
            'id' => $this->r->id,
            'name' => $this->r->name,
            'shortname' => $this->r->shortname,
            'description' => $this->r->description,
            'slots' => $this->r->slots,
            'context_id' => $this->context()->id,
            'startdate' => $this->r->startdate,
            'enddate' => $this->r->enddate,
            "aggregation" => $this->r->aggregation,
            "aggregation_config" => $this->aggregator->config_string(),
            'aggregation_info' => $this->aggregator->basic_model(),
            /*'association' => [
                'cohorts' => associationservice::associated_cohorts($this->r->id), 
                'users' => associationservice::associated_users($this->r->id),
            ],*/            
            'studylines' => [],
        ];

        $children = studyline::find_studyplan_children($this);
        foreach($children as $c)
        {
            $model['studylines'][] = $c->editor_model();
        }

        if(has_capability('local/treestudyplan:forcescales', \context_system::instance())){
            
            if(!array_key_exists('advanced',$model)){
                // Create advanced node if it does not exist
                $model['advanced'] = [];
            }

            // get a list of available scales
            $scales = array_map( function($scale){
                return [ "id" => $scale->id, "name" => $scale->name,];
                }, \grade_scale::fetch_all(array('courseid'=>0)) ) ;

            $model['advanced']['force_scales'] = [
                'scales' => $scales,
            ];
        }


        return $model;
    }

    public static function add($fields){
        global $CFG, $DB;
 
        $addable = ['name','shortname','description','context_id','slots','startdate','enddate','aggregation','aggregation_config'];
        $info = ['enddate' => null ];
        foreach($addable as $f){
            if(array_key_exists($f,$fields)){
                $info[$f] = $fields[$f];
            }
        }
        $id = $DB->insert_record(self::TABLE, $info);
        return self::findById($id); // make sure the new studyplan is immediately cached
    }

    public function edit($fields){
        global $DB;
        $editable = ['name','shortname','description','context_id','slots','startdate','enddate','aggregation','aggregation_config'];
        $info = ['id' => $this->id,];
        foreach($editable as $f){
            if(array_key_exists($f,$fields)){
                $info[$f] = $fields[$f];
            }
        }
        $DB->update_record(self::TABLE, $info);
        //reload record after edit
        $this->r = $DB->get_record(self::TABLE,['id' => $this->id],"*",MUST_EXIST);
        
        //reload the context...
        $this->context = null; 
        $this->context();
        // reload aggregator
        $this->aggregator = aggregator::createOrDefault($this->r->aggregation, $this->r->aggregation_config); 
        return $this;
    }

    public function delete($force=false){
        global $DB;

        if($force){
            $children = studyline::find_studyplan_children($this);
            foreach($children as $c){
                $c->delete($force);
            }
        }

        if($DB->count_records('local_treestudyplan_line',['studyplan_id' => $this->id]) > 0){
            return success::fail('cannot delete studyplan that still has studylines');
        }
        else
        {
            $DB->delete_records('local_treestudyplan', ['id' => $this->id]);
            return success::success();
        }
    }

    public static function find_all($contextid=-1){
        global $DB, $USER;
        $list = [];

        if($contextid <= 0){
            $ids = $DB->get_fieldset_select(self::TABLE,"id","");
        }
        else{
            if($contextid == 1){
                $contextid = 1;
                $where = "context_id <= :contextid OR context_id IS NULL";
            } else {
                $where = "context_id = :contextid";
            }
            $ids = $DB->get_fieldset_select(self::TABLE,"id",$where,["contextid" => $contextid]);
        }
        
        foreach($ids as $id)
        {
            $list[] = studyplan::findById($id);
        }
        return $list;
    }

    public static function find_by_shortname($shortname, $contextid = 0): array{
        global $DB;
        $list = [];

        $where = "shortname = :shortname AND context_id = :contextid";
        if($contextid == 0){
            $where .= "OR context_id IS NULL";
        }
        $ids = $DB->get_fieldset_select(self::TABLE,"id",$where,["shortname"=>$shortname, "contextid" => $contextid]);
        foreach($ids as $id)
        {
            $list[] = studyplan::findById($id);
        }
        return $list;
    }

    public static function find_for_user($userid)
    {
        global $DB;

        $sql = "SELECT s.id FROM {local_treestudyplan} s 
                INNER JOIN {local_treestudyplan_cohort} j ON j.studyplan_id = s.id
                INNER JOIN {cohort_members} cm ON j.cohort_id = cm.cohortid
                WHERE cm.userid = :userid";
        $cohort_plan_ids = $DB->get_fieldset_sql($sql, ['userid' => $userid]);

        $sql = "SELECT s.id FROM {local_treestudyplan} s 
                INNER JOIN {local_treestudyplan_user} j ON j.studyplan_id = s.id
                WHERE j.user_id = :userid";
        $user_plan_ids = $DB->get_fieldset_sql($sql, ['userid' => $userid]);

        $plans = [];
        foreach($cohort_plan_ids as $id) {
            $plans[$id] = self::findById($id);
        }
        foreach($user_plan_ids as $id) {
            if(!array_key_exists($id,$plans)){
                $plans[$id] = self::findById($id);
            }
        }

        return $plans;

    }

    /**
     * Find The active studyplans where the specified user is a teacher
     * (Has the  mod/assign::grade capability in one of the linked courses)
     * TODO: OPTIMIZE THIS CHECK!!!
     */
    public static function find_teaching($userid){
        global $DB;
        $list = [];

        // First find all active study plans

        $sql = "SELECT s.id FROM {local_treestudyplan} s 
            WHERE startdate <= NOW() and enddate >= NOW()";
        $plan_ids = $DB->get_fieldset_sql($sql, []);

        foreach($plan_ids as $planid) {
            $sql = "SELECT i.course_id FROM mdl_local_treestudyplan_item i 
                    INNER JOIN mdl_local_treestudyplan_line l ON i.line_id = l.id 
                    WHERE l.studyplan_id = :plan_id AND i.course_id IS NOT NULL";
            $course_ids = $DB->get_fieldset_sql($sql, ["plan_id" => $planid]);

            $linked = false;
            foreach($course_ids as $cid){
                $coursecontext =  \context_course::instance($cid);
                if (is_enrolled($coursecontext, $userid, 'mod/assign:grade')){
                    $linked = true; 
                    break; // No need to search further
                }
            }

            if($linked)
            {
                $list[$planid] =  self::findById($planid);
            }

        }

        return $list;
    }


    static public function exist_for_user($userid)
    {
        global $DB;
        $count = 0;
        $sql = "SELECT s.* FROM {local_treestudyplan} s 
                INNER JOIN {local_treestudyplan_cohort} j ON j.studyplan_id = s.id
                INNER JOIN {cohort_members} cm ON j.cohort_id = cm.cohortid
                WHERE cm.userid = :userid";
        $count += $DB->count_records_sql($sql, ['userid' => $userid]);

        $sql = "SELECT s.* FROM {local_treestudyplan} s 
                INNER JOIN {local_treestudyplan_user} j ON j.studyplan_id = s.id
                WHERE j.user_id = :userid";
        $count += $DB->count_records_sql($sql, ['userid' => $userid]);

        return ($count > 0);
    }

    /** 
     * Retrieve the users linked to this studyplan.
     * @return array of User objects
     */
    public function find_linked_users(){
        global $DB;

        $users = [];

        $uids = $this->find_linked_userids();

        foreach($uids as $uid){
            $users[] = $DB->get_record("user",["id"=>$uid]);
        }

        return $users;
    }

     /** 
     * Retrieve the user id's of the users linked to this studyplan.
     * @return array of int (User Id)
     */
    public function find_linked_userids(): array {
        global $DB;

        if($this->linked_userids === null){
            $uids = [];
            // First get directly linked userids
            $sql = "SELECT j.user_id FROM {local_treestudyplan_user} j
                    WHERE j.studyplan_id  = :planid";
            $ulist = $DB->get_fieldset_sql($sql, ['planid' => $this->id]);

            $uids = array_merge($uids,$ulist);
            foreach($ulist as $uid){
                $users[] = $DB->get_record("user",["id"=>$uid]);
            }

            // Next het users linked though cohort
            $sql = "SELECT cm.userid FROM  {local_treestudyplan_cohort} j 
                    INNER JOIN {cohort_members} cm ON j.cohort_id = cm.cohortid
                    WHERE j.studyplan_id = :planid";
            $ulist = $DB->get_fieldset_sql($sql, ['planid' => $this->id]);

            $uids = array_merge($uids,$ulist);

            $this->linked_userids = array_unique($uids);
        }
        return $this->linked_userids;
    }

    /** Check if this studyplan is linked to a particular user
     * @param bool|stdClass $user The userid or user record of the user 
     */
    public function has_linked_user($user){
        if(is_int($user)){
            $userid = $user;
        } else {
            $userid = $user->id;
        }
        $uids = $this->find_linked_userids();
        if(in_array($userid,$uids)){
            return true;
        } else {
            return false;
        }
    }

    public static function user_structure($value=VALUE_REQUIRED){
        return new \external_single_structure([
            "id" => new \external_value(PARAM_INT, 'id of studyplan'),
            "name" => new \external_value(PARAM_TEXT, 'name of studyplan'),
            "shortname"=> new \external_value(PARAM_TEXT, 'shortname of studyplan'),
            "description"=> new \external_value(PARAM_TEXT, 'description of studyplan'),
            "slots" => new \external_value(PARAM_INT, 'number of slots in studyplan'),
            "startdate" => new \external_value(PARAM_TEXT, 'start date of studyplan'),
            "enddate" => new \external_value(PARAM_TEXT, 'end date of studyplan'),
            "studylines" => new \external_multiple_structure(studyline::user_structure()),
            "aggregation_info" => aggregator::basic_structure(),
        ],'Studyplan with user info',$value);

    }

    public function user_model($userid){

        $model = [
            'id' => $this->r->id,
            'name' => $this->r->name,
            'shortname' => $this->r->shortname,
            'description' => $this->r->description,
            'slots' => $this->r->slots,
            'startdate' => $this->r->startdate,
            'enddate' => $this->r->enddate,
            'studylines' => [],
            'aggregation_info' => $this->aggregator->basic_model(),
        ];

        $children = studyline::find_studyplan_children($this);
        foreach($children as $c)
        {
            $model['studylines'][] = $c->user_model($userid);
        }
        return $model;
    }

    public static function duplicate_plan($plan_id,$name,$shortname)
    {
        $ori = self::findById($plan_id);
        $new = $ori->duplicate($name,$shortname);
        return $new->simple_model();
    }

    public function duplicate($name,$shortname)
    {
        // First duplicate the studyplan structure
        $new =studyplan::add([
            'name' => $name,
            'shortname' => $shortname,
            'description' => $this->r->description,
            'slots' => $this->r->slots,
            'startdate' => $this->r->startdate,
            'enddate' => empty($this->r->enddate)?null:$this->r->enddate,
        ]);
        
        // next, copy the studylines

        $children = studyline::find_studyplan_children($this);
        $itemtranslation = [];
        $linetranslation = [];
        foreach($children as $c){
            $newchild = $c->duplicate($this,$itemtranslation);
            $linetranslation[$c->id()] = $newchild->id();
        }

        // now the itemtranslation array contains all of the old child id's as keys and all of the related new ids as values
        // (feature of the studyline::duplicate function)
        // use this to recreate the lines in the new plan
        foreach(array_keys($itemtranslation) as $item_id){
            // copy based on the outgoing connections of each item, to avoid duplicates
            $connections  = studyitemconnection::find_outgoing($item_id);
            foreach($connections as $conn){
                studyitemconnection::connect($itemtranslation[$conn->from_id],$itemtranslation[$conn->to_id]);
            }
        }
        return $new;
    }   

    public static function export_structure()
    {
        return new \external_single_structure([
            "format" => new \external_value(PARAM_TEXT, 'format of studyplan export'),
            "content"=> new \external_value(PARAM_TEXT, 'exported studyplan content'),
        ],'Exported studyplan');
    }

    public function export_plan()
    {
        $model = $this->export_model();
        $json = json_encode([
            "type"=>"studyplan",
            "version"=>1.0,
            "studyplan"=>$model
            ],\JSON_PRETTY_PRINT);
        return [ "format" => "application/json", "content" => $json];
    }

    public function export_plan_csv()
    {
        $model = $this->editor_model();
        
        $slots = intval($model["slots"]);
        // First line
        $csv = "\"Studyline[{$slots}]\"";
        for($i = 1; $i <= $slots; $i++){
            $csv .= ",\"P{$i}\"";
        }
        $csv .= "\r\n";
        // next, make one line per studyline
        foreach($model["studylines"] as $line){
            // determine how many fields are simultaneous in the line at maximum
            $maxlines = 1;
            for($i = 1; $i <= $slots; $i++){
                if(count($line["slots"]) > $i){
                    $ct = 0;
                    foreach($line["slots"][$i][studyline::SLOTSET_COMPETENCY] as $itm){
                        if($itm["type"] == "course"){
                            $ct += 1;
                        }
                    }
                    if($ct > $maxlines){
                        $maxlines = $ct;
                    }

                }
            }

            for($lct = 0; $lct < $maxlines; $lct++){
                $csv .= "\"{$line["name"]}\"";
                for($i = 1; $i <= $slots; $i++){
                    $filled = false;
                    if(count($line["slots"]) > $i){
                        $ct = 0;
                        foreach($line["slots"][$i][studyline::SLOTSET_COMPETENCY] as $itm){
                            if($itm["type"] == "course"){
                                if($ct == $lct){
                                    $csv .= ",\"";
                                    $csv .= $itm["course"]["fullname"];
                                    $csv .= "\r\n";
                                    $first = true;
                                    foreach($itm["course"]["grades"] as $g){
                                        if($g["selected"]){
                                            if($first){
                                                $first = false;
                                            }
                                            else{ 
                                                $csv .= "\r\n";
                                            }
                                            $csv .= "- ".str_replace('"', '\'', $g["name"]);
                                        }
                                    }
                                    $csv .= "\"";
                                    $filled = true;
                                    break;
                                }
                                $ct++;
                            }
                        }
                    } 
                    if(!$filled) {
                        $csv .= ",\"\"";
                    }
                }
                $csv .= "\r\n";
            }
        }

        return [ "format" => "text/csv", "content" => $csv];
    }

    public function export_studylines(){
        $model = $this->export_studylines_model();
        $json = json_encode([
            "type"=>"studylines",
            "version"=>1.0,
            "studylines"=>$model,
            ],\JSON_PRETTY_PRINT);
        return [ "format" => "application/json", "content" => $json];
    }

    public function export_model()
    {
        $model = [
            'name' => $this->r->name,
            'shortname' => $this->r->shortname,
            'description' => $this->r->description,
            'slots' => $this->r->slots,
            'startdate' => $this->r->startdate,
            'enddate' => $this->r->enddate,
            "aggregation" => $this->r->aggregation,
            "aggregation_config" => json_decode($this->aggregator->config_string()),
            'aggregation_info' => $this->aggregator->basic_model(),
            'studylines' => $this->export_studylines_model(),
        ];
        return $model;
    }

    public function export_studylines_model()
    {
        $children = studyline::find_studyplan_children($this);
        $lines = [];
        foreach($children as $c)
        {
            $lines[] = $c->export_model();
        }
        return $lines;
    }

    public static function import_studyplan($content,$format="application/json",$context_id=1)
    {
        if($format != "application/json") { return false;}
        
        $content = json_decode($content,true);
        if($content["type"] == "studyplan" && $content["version"] >= 1.0){
        
            // Make sure the aggregation_config is re-encoded as json text
            $content["studyplan"]["aggregation_config"] = json_encode($content["studyplan"]["aggregation_config"]);

            // And make sure the context_id is set to the 
            $content["studyplan"]["context_id"] = $context_id;
            $plan = self::add($content["studyplan"]);
            return $plan->import_studylines_model($content["studyplan"]["studylines"]);

        }
        else {
            error_log("Invalid format and type: {$content['type']} version {$content['version']}");
            return false;
        }
    }

    public function import_studylines($content,$format="application/json")
    {
        if($format != "application/json") { return false;}
        $content = json_decode($content,true);
        if($content["type"] == "studylines" && $content["version"] >= 1.0){
            return $this->import_studylines_model($content["studylines"]);
        }
        else if($content["type"] == "studyplan" && $content["version"] >= 1.0){
            return $this->import_studylines_model($content["studyplan"]["studylines"]);
        }
        else {
            return false;
        }
    }

    protected function find_studyline_by_shortname($shortname){
        $children = studyline::find_studyplan_children($this);
        foreach($children as $l){
            if($shortname == $l->shortname()){
                return $l;
            }
        }
        return null;
    }

    protected function import_studylines_model($model)
    {
        // First attempt to map each studyline model to an existing or new line
        $line_map = [];
        foreach($model as $ix => $linemodel){
            $line = $this->find_studyline_by_shortname($linemodel["shortname"]);
            if(empty($line)){
                $linemodel["studyplan_id"] = $this->id;
                $line = studyline::add($linemodel);
            } else {
                //$line->edit($linemodel); // Update the line with the settings from the imported file
            }
            $line_map[$ix] = $line;
        }

        // next, let each study line import the study items
        $itemtranslation = []; 
        $connections = [];
        foreach($model as $ix => $linemodel){
            $line_map[$ix]->import_studyitems($linemodel["slots"],$itemtranslation,$connections);
        }

        // Finally, create the links between the study items
        foreach($connections as $from => $dests){
            foreach($dests as $to){
                studyitemconnection::connect($from,$itemtranslation[$to]);
            }
        }
        return true;
    }

    /**
     * Mark the studyplan as changed regarding courses and associated cohorts
     */
    public function mark_csync_changed(){
        global $DB;
        $DB->update_record(self::TABLE, ['id' => $this->id,"csync_flag" => 1]);
        $this->r->csync_flag = 1; //manually set it in the cache, if something unexpected happened, an exception has already been thrown anyway
    }

    /**
     * Clear the csync mark
     */
    public function clear_csync_changed(){
        global $DB;
        $DB->update_record(self::TABLE, ['id' => $this->id,"csync_flag" => 0]);
        $this->r->csync_flag = 0; //manually set it in the cache, if something unexpected happened, an exception has already been thrown anyway
    }

    public function has_csync_changed(){
        return ($this->r->csync_flag > 0)?true:false;
    }

    /**
     * See if the specified course id is linked in this studyplan
     */
    public function course_linked($courseid){
        global $DB;

        $sql = "SELECT COUNT(i.id)
                FROM {local_treestudyplan}
                INNER JOIN {local_treestudyplan_line} l ON p.id = l.studyplan_id
                INNER JOIN {local_treestudyplan_item} i ON l.id = i.line_id
                WHERE p.id = :planid 
                   AND i.course_id = :courseid";
        $count = $DB->get_field_sql($sql,["courseid" => $courseid, "planid" => $this->id]);

        return ($count > 0)?true:false;
    }

    /**
     * List the course id is linked in this studyplan
     * Used for cohort enrolment cascading
     */
    public function get_linked_course_ids(){
        global $DB;

        $sql = "SELECT i.course_id
                FROM {local_treestudyplan} p
                INNER JOIN {local_treestudyplan_line} l ON p.id = l.studyplan_id
                INNER JOIN {local_treestudyplan_item} i ON l.id = i.line_id
                WHERE p.id = :studyplan_id AND i.type = :itemtype";
        $fields = $DB->get_fieldset_sql($sql,["studyplan_id" => $this->id,"itemtype" => studyitem::COURSE]);

        return $fields;
    }

    /**
     * List the cohort id's associated with this studyplan
     */
    public function get_linked_cohort_ids(){
		global $CFG, $DB;

        $sql = "SELECT DISTINCT j.cohort_id FROM {local_treestudyplan_cohort} j
                WHERE j.studyplan_id = :studyplan_id";
        $fields = $DB->get_fieldset_sql($sql, ['studyplan_id' => $this->id]);
        return $fields;
    }

    /**
     * List the user id's explicitly associated with this studyplan
     */
    public function get_linked_user_ids(){
		global $CFG, $DB;

        $sql = "SELECT DISTINCT j.user_id FROM {local_treestudyplan_user} j
                WHERE j.studyplan_id = :studyplan_id";
        $fields = $DB->get_fieldset_sql($sql, ['studyplan_id' => $this->id]);
        return $fields;
    }
    /**
     * See if the specified course id is linked in this studyplan
     */
    public function badge_linked($badgeid){
        global $DB;

        $sql = "SELECT COUNT(i.id)
                FROM {local_treestudyplan}
                INNER JOIN {local_treestudyplan_line} l ON p.id = l.studyplan_id
                INNER JOIN {local_treestudyplan_item} i ON l.id = i.line_id
                WHERE p.id = :planid 
                   AND i.badge_id = :badgeid";
        $count = $DB->get_field_sql($sql,["badgeid" => $badgeid, "planid" => $this->id]);

        return ($count > 0)?true:false;
    }


}