General help

okay let's start with a short piece of code.

$lowerboundaries = new stdClass();
$lowerboundaries=  array_fill_keys($letters,null);
$higherboundaries=new stdClass();
$higherboundaries=array_fill_keys($letters,null);
$i=1;
foreach ($letters as $letter){
    $lowerboundary = new stdClass();$higherboundary =new stdClass();
    $lowerboundary->value=0;$higherboundary->value=0;
    $lowerboundary->value='grp_gradeboundaries_lower['.$i.']';$higherboundary->value='grp_gradeboundaries_higher['.$i.']';

    $lowerboundaries[$letter]=$lowerboundary;

    $higherboundaries[$letter]=$higherboundary;
$i++;
}

$grader = new grade_report_gradedist($course->id, $gpr, $context, $letters,$higherboundaries,$lowerboundaries);

This is the code i am using in ajax_handler and doubts to be wrong on inserting array values. If it is okay I pass the values to

$grader = new grade_report_gradedist($course->id, $gpr, $context, $letters,$higherboundaries,$lowerboundaries);

and in lib.php:

class grade_report_gradedist extends grade_report_grader {
    private $letters;
    private $higherboundaries;
    private $lowerboundaries;
    
    public function __construct($courseid, $gpr, $context, $letters,$higherboundaries,$lowerboundaries, $page=null, $sortitemid=null) {
        parent::__construct($courseid, $gpr, $context, $page, $sortitemid);

        $this->letters = $letters;
        $this->lowerboundaries= new stdClass();
        $this->lowerboundaries=$lowerboundaries;
        $this->higherboundaries=new stdClass();
        $this->higherboundaries=$higherboundaries;
    }

I think it will be also fine.. after this in lib.php i do have functions

public function load_distribution($letters, $gradeitem=0, $groupid=0, $groupingid=0) {
        global $CFG, $DB;

        $this->load_users();
        $selectedusers = array();
        if ($groupingid == 0) {
            if ($groupid == 0) { // Tackle all users.
                $selectedusers = $this->users;
            } else { // Tackle the users of a single group.
                $groupusers = groups_get_members($groupid);
                $selectedusers = array_intersect_key($groupusers, $this->users);
            }
        } else { // Tackle the users of the groups of a grouping.
            $groupsusers = groups_get_grouping_members($groupingid);
            $selectedusers = array_intersect_key($groupsusers, $this->users);
        }

        $userids = array_keys($selectedusers);

        $sql = "SELECT g.*, gi.grademax, gi.grademin
                  FROM {grade_items} gi,
                       {grade_grades} g
                WHERE g.itemid = gi.id AND gi.courseid = :courseid
                AND g.itemid = :gradeitem";
        $params = array('gradeitem' => $gradeitem, 'courseid' => $this->courseid);

        //krsort($this->letters); // Just to be sure.

        $total = 0;
        $count = 0;

        $return = new stdClass();
        $return->distribution = array_fill_keys($this->letters, null);
        $return->coverage = array(0, 0);

        foreach ($this->letters as $letter) {
            $gradedist = new stdClass();
            $gradedist->count       = 0;
            $return->distribution[$letter] = $gradedist;
        }

        if ($grades = $DB->get_records_sql($sql, $params)) {
            foreach ($grades as $grade) {
                if (in_array($grade->userid, $userids) && array_key_exists($grade->itemid, $this->gtree->get_items())) {
                    // Some items may not be present!!
                    if (is_null($grade->finalgrade)) {
                        continue;
                    }
                    $total++;

                    // Calculate gradeletter.
                    $letter = $this->get_gradeletter($letters, $grade);

                    if (array_key_exists($letter, $return->distribution)) {
                        $return->distribution[$letter]->count++;
                        $count++;
                    }
                  
                }
            }
        }
        $return->coverage = array($total - $count, $total, ($total > 0) ? round(($total - $count) * 100 / $total, 2) : 0);
        return $return;
    }

    public function get_gradeletter($letters, $grade) {
        if (is_null($grade->finalgrade) || !$gradeitem = grade_item::fetch(array('id' => $grade->itemid))) {
            return '-';
        }

        // Map to range.
        $gradeint = $gradeitem->grademax - $gradeitem->grademin;
                     $value=$grade->finalgrade;
        // Calculate gradeletter.
        $value = bounded_number(0, $value, $gradeitem->grademax); // Just in case.
        foreach ($this->letters as $letter) {
           
            if (($value <=$this->higherboudaries[$letter]->value)&&($value >= $this->lowerboundaries[$letter]->value)) {
                return format_string($letter);
            }
            else{return '-';}
        }
    }

Now , if it is fine i will post another doubt in the code.