C:/xampp/htdocs/moodle/lib/grade/grade_category.php

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<?php

// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
defined('MOODLE_INTERNAL') || die();

require_once('grade_object.php');

class grade_category extends grade_object {
    public $table = 'grade_categories';

    public $required_fields = array('id', 'courseid', 'parent', 'depth', 'path', 'fullname', 'aggregation',
                                 'keephigh', 'droplow', 'aggregateonlygraded', 'aggregateoutcomes',
                                 'aggregatesubcats', 'timecreated', 'timemodified', 'hidden');

    public $courseid;

    public $parent;

    public $parent_category;

    public $depth = 0;

    public $path;

    public $fullname;

    public $aggregation = GRADE_AGGREGATE_MEAN;

    public $keephigh = 0;

    public $droplow = 0;

    public $aggregateonlygraded = 0;

    public $aggregateoutcomes = 0;

    public $aggregatesubcats = 0;

    public $children;

    public $all_children;

    public $grade_item;

    public $sortorder;

    public $forceable = array('aggregation', 'keephigh', 'droplow', 'aggregateonlygraded', 'aggregateoutcomes', 'aggregatesubcats');

    public $coefstring = null;

    public static function build_path($grade_category) {
        global $DB;

        if (empty($grade_category->parent)) {
            return '/'.$grade_category->id.'/';

        } else {
            $parent = $DB->get_record('grade_categories', array('id' => $grade_category->parent));
            return grade_category::build_path($parent).$grade_category->id.'/';
        }
    }

    public static function fetch($params) {
        return grade_object::fetch_helper('grade_categories', 'grade_category', $params);
    }

    public static function fetch_all($params) {
        return grade_object::fetch_all_helper('grade_categories', 'grade_category', $params);
    }

    public function update($source=null) {
        // load the grade item or create a new one
        $this->load_grade_item();

        // force recalculation of path;
        if (empty($this->path)) {
            $this->path  = grade_category::build_path($this);
            $this->depth = substr_count($this->path, '/') - 1;
            $updatechildren = true;

        } else {
            $updatechildren = false;
        }

        $this->apply_forced_settings();

        // these are exclusive
        if ($this->droplow > 0) {
            $this->keephigh = 0;

        } else if ($this->keephigh > 0) {
            $this->droplow = 0;
        }

        // Recalculate grades if needed
        if ($this->qualifies_for_regrading()) {
            $this->force_regrading();
        }

        $this->timemodified = time();

        $result = parent::update($source);

        // now update paths in all child categories
        if ($result and $updatechildren) {

            if ($children = grade_category::fetch_all(array('parent'=>$this->id))) {

                foreach ($children as $child) {
                    $child->path  = null;
                    $child->depth = 0;
                    $child->update($source);
                }
            }
        }

        return $result;
    }

    public function delete($source=null) {
        $grade_item = $this->load_grade_item();

        if ($this->is_course_category()) {

            if ($categories = grade_category::fetch_all(array('courseid'=>$this->courseid))) {

                foreach ($categories as $category) {

                    if ($category->id == $this->id) {
                        continue; // do not delete course category yet
                    }
                    $category->delete($source);
                }
            }

            if ($items = grade_item::fetch_all(array('courseid'=>$this->courseid))) {

                foreach ($items as $item) {

                    if ($item->id == $grade_item->id) {
                        continue; // do not delete course item yet
                    }
                    $item->delete($source);
                }
            }

        } else {
            $this->force_regrading();

            $parent = $this->load_parent_category();

            // Update children's categoryid/parent field first
            if ($children = grade_item::fetch_all(array('categoryid'=>$this->id))) {
                foreach ($children as $child) {
                    $child->set_parent($parent->id);
                }
            }

            if ($children = grade_category::fetch_all(array('parent'=>$this->id))) {
                foreach ($children as $child) {
                    $child->set_parent($parent->id);
                }
            }
        }

        // first delete the attached grade item and grades
        $grade_item->delete($source);

        // delete category itself
        return parent::delete($source);
    }

    public function insert($source=null) {

        if (empty($this->courseid)) {
            print_error('cannotinsertgrade');
        }

        if (empty($this->parent)) {
            $course_category = grade_category::fetch_course_category($this->courseid);
            $this->parent = $course_category->id;
        }

        $this->path = null;

        $this->timecreated = $this->timemodified = time();

        if (!parent::insert($source)) {
            debugging("Could not insert this category: " . print_r($this, true));
            return false;
        }

        $this->force_regrading();

        // build path and depth
        $this->update($source);

        return $this->id;
    }

    public function insert_course_category($courseid) {
        $this->courseid    = $courseid;
        $this->fullname    = '?';
        $this->path        = null;
        $this->parent      = null;
        $this->aggregation = GRADE_AGGREGATE_WEIGHTED_MEAN2;

        $this->apply_default_settings();
        $this->apply_forced_settings();

        $this->timecreated = $this->timemodified = time();

        if (!parent::insert('system')) {
            debugging("Could not insert this category: " . print_r($this, true));
            return false;
        }

        // build path and depth
        $this->update('system');

        return $this->id;
    }

    public function qualifies_for_regrading() {
        if (empty($this->id)) {
            debugging("Can not regrade non existing category");
            return false;
        }

        $db_item = grade_category::fetch(array('id'=>$this->id));

        $aggregationdiff = $db_item->aggregation         != $this->aggregation;
        $keephighdiff    = $db_item->keephigh            != $this->keephigh;
        $droplowdiff     = $db_item->droplow             != $this->droplow;
        $aggonlygrddiff  = $db_item->aggregateonlygraded != $this->aggregateonlygraded;
        $aggoutcomesdiff = $db_item->aggregateoutcomes   != $this->aggregateoutcomes;
        $aggsubcatsdiff  = $db_item->aggregatesubcats    != $this->aggregatesubcats;

        return ($aggregationdiff || $keephighdiff || $droplowdiff || $aggonlygrddiff || $aggoutcomesdiff || $aggsubcatsdiff);
    }

    public function force_regrading() {
        $grade_item = $this->load_grade_item();
        $grade_item->force_regrading();
    }

    public function generate_grades($userid=null) {
        global $CFG, $DB;

        $this->load_grade_item();

        if ($this->grade_item->is_locked()) {
            return true; // no need to recalculate locked items
        }

        // find grade items of immediate children (category or grade items) and force site settings
        $depends_on = $this->grade_item->depends_on();

        if (empty($depends_on)) {
            $items = false;

        } else {
            list($usql, $params) = $DB->get_in_or_equal($depends_on);
            $sql = "SELECT *
                      FROM {grade_items}
                     WHERE id $usql";
            $items = $DB->get_records_sql($sql, $params);
        }

        // needed mostly for SUM agg type
        $this->auto_update_max($items);

        $grade_inst = new grade_grade();
        $fields = 'g.'.implode(',g.', $grade_inst->required_fields);

        // where to look for final grades - include grade of this item too, we will store the results there
        $gis = array_merge($depends_on, array($this->grade_item->id));
        list($usql, $params) = $DB->get_in_or_equal($gis);

        if ($userid) {
            $usersql = "AND g.userid=?";
            $params[] = $userid;

        } else {
            $usersql = "";
        }

        $sql = "SELECT $fields
                  FROM {grade_grades} g, {grade_items} gi
                 WHERE gi.id = g.itemid AND gi.id $usql $usersql
              ORDER BY g.userid";

        // group the results by userid and aggregate the grades for this user
        $rs = $DB->get_recordset_sql($sql, $params);
        if ($rs->valid()) {
            $prevuser = 0;
            $grade_values = array();
            $excluded     = array();
            $oldgrade     = null;

            foreach ($rs as $used) {

                if ($used->userid != $prevuser) {
                    $this->aggregate_grades($prevuser, $items, $grade_values, $oldgrade, $excluded);
                    $prevuser = $used->userid;
                    $grade_values = array();
                    $excluded     = array();
                    $oldgrade     = null;
                }
                $grade_values[$used->itemid] = $used->finalgrade;

                if ($used->excluded) {
                    $excluded[] = $used->itemid;
                }

                if ($this->grade_item->id == $used->itemid) {
                    $oldgrade = $used;
                }
            }
            $this->aggregate_grades($prevuser, $items, $grade_values, $oldgrade, $excluded);//the last one
        }
        $rs->close();

        return true;
    }

    private function aggregate_grades($userid, $items, $grade_values, $oldgrade, $excluded) {
        global $CFG;
        if (empty($userid)) {
            //ignore first call
            return;
        }

        if ($oldgrade) {
            $oldfinalgrade = $oldgrade->finalgrade;
            $grade = new grade_grade($oldgrade, false);
            $grade->grade_item =& $this->grade_item;

        } else {
            // insert final grade - it will be needed later anyway
            $grade = new grade_grade(array('itemid'=>$this->grade_item->id, 'userid'=>$userid), false);
            $grade->grade_item =& $this->grade_item;
            $grade->insert('system');
            $oldfinalgrade = null;
        }

        // no need to recalculate locked or overridden grades
        if ($grade->is_locked() or $grade->is_overridden()) {
            return;
        }

        // can not use own final category grade in calculation
        unset($grade_values[$this->grade_item->id]);


        // sum is a special aggregation types - it adjusts the min max, does not use relative values
        if ($this->aggregation == GRADE_AGGREGATE_SUM) {
            $this->sum_grades($grade, $oldfinalgrade, $items, $grade_values, $excluded);
            return;
        }

        // if no grades calculation possible or grading not allowed clear final grade
        if (empty($grade_values) or empty($items) or ($this->grade_item->gradetype != GRADE_TYPE_VALUE and $this->grade_item->gradetype != GRADE_TYPE_SCALE)) {
            $grade->finalgrade = null;

            if (!is_null($oldfinalgrade)) {
                $grade->update('aggregation');
            }
            return;
        }

        // normalize the grades first - all will have value 0...1
        // ungraded items are not used in aggregation
        foreach ($grade_values as $itemid=>$v) {

            if (is_null($v)) {
                // null means no grade
                unset($grade_values[$itemid]);
                continue;

            } else if (in_array($itemid, $excluded)) {
                unset($grade_values[$itemid]);
                continue;
            }
            $grade_values[$itemid] = grade_grade::standardise_score($v, $items[$itemid]->grademin, $items[$itemid]->grademax, 0, 1);
        }

        // use min grade if grade missing for these types
        if (!$this->aggregateonlygraded) {

            foreach ($items as $itemid=>$value) {

                if (!isset($grade_values[$itemid]) and !in_array($itemid, $excluded)) {
                    $grade_values[$itemid] = 0;
                }
            }
        }

        // limit and sort
        $this->apply_limit_rules($grade_values, $items);
        asort($grade_values, SORT_NUMERIC);

        // let's see we have still enough grades to do any statistics
        if (count($grade_values) == 0) {
            // not enough attempts yet
            $grade->finalgrade = null;

            if (!is_null($oldfinalgrade)) {
                $grade->update('aggregation');
            }
            return;
        }

        // do the maths
        $agg_grade = $this->aggregate_values($grade_values, $items);

        // recalculate the grade back to requested range
        $finalgrade = grade_grade::standardise_score($agg_grade, 0, 1, $this->grade_item->grademin, $this->grade_item->grademax);

        $grade->finalgrade = $this->grade_item->bounded_grade($finalgrade);

        // update in db if changed
        if (grade_floats_different($grade->finalgrade, $oldfinalgrade)) {
            $grade->update('aggregation');
        }

        return;
    }

    public function aggregate_values($grade_values, $items) {
        switch ($this->aggregation) {

            case GRADE_AGGREGATE_MEDIAN: // Middle point value in the set: ignores frequencies
                $num = count($grade_values);
                $grades = array_values($grade_values);

                if ($num % 2 == 0) {
                    $agg_grade = ($grades[intval($num/2)-1] + $grades[intval($num/2)]) / 2;

                } else {
                    $agg_grade = $grades[intval(($num/2)-0.5)];
                }
                break;

            case GRADE_AGGREGATE_MIN:
                $agg_grade = reset($grade_values);
                break;

            case GRADE_AGGREGATE_MAX:
                $agg_grade = array_pop($grade_values);
                break;

            case GRADE_AGGREGATE_MODE:       // the most common value, average used if multimode
                // array_count_values only counts INT and STRING, so if grades are floats we must convert them to string
                $converted_grade_values = array();

                foreach ($grade_values as $k => $gv) {

                    if (!is_int($gv) && !is_string($gv)) {
                        $converted_grade_values[$k] = (string) $gv;

                    } else {
                        $converted_grade_values[$k] = $gv;
                    }
                }

                $freq = array_count_values($converted_grade_values);
                arsort($freq);                      // sort by frequency keeping keys
                $top = reset($freq);               // highest frequency count
                $modes = array_keys($freq, $top);  // search for all modes (have the same highest count)
                rsort($modes, SORT_NUMERIC);       // get highest mode
                $agg_grade = reset($modes);
                break;

            case GRADE_AGGREGATE_WEIGHTED_MEAN: // Weighted average of all existing final grades, weight specified in coef
                $weightsum = 0;
                $sum       = 0;

                foreach ($grade_values as $itemid=>$grade_value) {

                    if ($items[$itemid]->aggregationcoef <= 0) {
                        continue;
                    }
                    $weightsum += $items[$itemid]->aggregationcoef;
                    $sum       += $items[$itemid]->aggregationcoef * $grade_value;
                }

                if ($weightsum == 0) {
                    $agg_grade = null;

                } else {
                    $agg_grade = $sum / $weightsum;
                }
                break;

            case GRADE_AGGREGATE_WEIGHTED_MEAN2:
                // Weighted average of all existing final grades with optional extra credit flag,
                // weight is the range of grade (usually grademax)
                $weightsum = 0;
                $sum       = null;

                foreach ($grade_values as $itemid=>$grade_value) {
                    $weight = $items[$itemid]->grademax - $items[$itemid]->grademin;

                    if ($weight <= 0) {
                        continue;
                    }

                    if ($items[$itemid]->aggregationcoef == 0) {
                        $weightsum += $weight;
                    }
                    $sum += $weight * $grade_value;
                }

                if ($weightsum == 0) {
                    $agg_grade = $sum; // only extra credits

                } else {
                    $agg_grade = $sum / $weightsum;
                }
                break;

            case GRADE_AGGREGATE_EXTRACREDIT_MEAN: // special average
                $num = 0;
                $sum = null;

                foreach ($grade_values as $itemid=>$grade_value) {

                    if ($items[$itemid]->aggregationcoef == 0) {
                        $num += 1;
                        $sum += $grade_value;

                    } else if ($items[$itemid]->aggregationcoef > 0) {
                        $sum += $items[$itemid]->aggregationcoef * $grade_value;
                    }
                }

                if ($num == 0) {
                    $agg_grade = $sum; // only extra credits or wrong coefs

                } else {
                    $agg_grade = $sum / $num;
                }
                break;

            case GRADE_AGGREGATE_MEAN:    // Arithmetic average of all grade items (if ungraded aggregated, NULL counted as minimum)
            default:
                $num = count($grade_values);
                $sum = array_sum($grade_values);
                $agg_grade = $sum / $num;
                break;
        }

        return $agg_grade;
    }

    private function auto_update_max($items) {
        if ($this->aggregation != GRADE_AGGREGATE_SUM) {
            // not needed at all
            return;
        }

        if (!$items) {

            if ($this->grade_item->grademax != 0 or $this->grade_item->gradetype != GRADE_TYPE_VALUE) {
                $this->grade_item->grademax  = 0;
                $this->grade_item->grademin  = 0;
                $this->grade_item->gradetype = GRADE_TYPE_VALUE;
                $this->grade_item->update('aggregation');
            }
            return;
        }

        //find max grade possible
        $maxes = array();

        foreach ($items as $item) {

            if ($item->aggregationcoef > 0) {
                // extra credit from this activity - does not affect total
                continue;
            }

            if ($item->gradetype == GRADE_TYPE_VALUE) {
                $maxes[$item->id] = $item->grademax;

            } else if ($item->gradetype == GRADE_TYPE_SCALE) {
                $maxes[$item->id] = $item->grademax; // 0 = nograde, 1 = first scale item, 2 = second scale item
            }
        }
        // apply droplow and keephigh
        $this->apply_limit_rules($maxes, $items);
        $max = array_sum($maxes);

        // update db if anything changed
        if ($this->grade_item->grademax != $max or $this->grade_item->grademin != 0 or $this->grade_item->gradetype != GRADE_TYPE_VALUE) {
            $this->grade_item->grademax  = $max;
            $this->grade_item->grademin  = 0;
            $this->grade_item->gradetype = GRADE_TYPE_VALUE;
            $this->grade_item->update('aggregation');
        }
    }

    private function sum_grades(&$grade, $oldfinalgrade, $items, $grade_values, $excluded) {
        if (empty($items)) {
            return null;
        }

        // ungraded and excluded items are not used in aggregation
        foreach ($grade_values as $itemid=>$v) {

            if (is_null($v)) {
                unset($grade_values[$itemid]);

            } else if (in_array($itemid, $excluded)) {
                unset($grade_values[$itemid]);
            }
        }

        // use 0 if grade missing, droplow used and aggregating all items
        if (!$this->aggregateonlygraded and !empty($this->droplow)) {

            foreach ($items as $itemid=>$value) {

                if (!isset($grade_values[$itemid]) and !in_array($itemid, $excluded)) {
                    $grade_values[$itemid] = 0;
                }
            }
        }

        $this->apply_limit_rules($grade_values, $items);

        $sum = array_sum($grade_values);
        $grade->finalgrade = $this->grade_item->bounded_grade($sum);

        // update in db if changed
        if (grade_floats_different($grade->finalgrade, $oldfinalgrade)) {
            $grade->update('aggregation');
        }

        return;
    }

    public function apply_limit_rules(&$grade_values, $items) {
        $extraused = $this->is_extracredit_used();

        if (!empty($this->droplow)) {
            asort($grade_values, SORT_NUMERIC);
            $dropped = 0;

            foreach ($grade_values as $itemid=>$value) {

                if ($dropped < $this->droplow) {

                    if ($extraused and $items[$itemid]->aggregationcoef > 0) {
                        // no drop low for extra credits

                    } else {
                        unset($grade_values[$itemid]);
                        $dropped++;
                    }

                } else {
                    // we have dropped enough
                    break;
                }
            }

        } else if (!empty($this->keephigh)) {
            arsort($grade_values, SORT_NUMERIC);
            $kept = 0;

            foreach ($grade_values as $itemid=>$value) {

                if ($extraused and $items[$itemid]->aggregationcoef > 0) {
                    // we keep all extra credits

                } else if ($kept < $this->keephigh) {
                    $kept++;

                } else {
                    unset($grade_values[$itemid]);
                }
            }
        }
    }

    function is_extracredit_used() {
        return ($this->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN2
             or $this->aggregation == GRADE_AGGREGATE_EXTRACREDIT_MEAN
             or $this->aggregation == GRADE_AGGREGATE_SUM);
    }

    public function is_aggregationcoef_used() {
        return ($this->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN
             or $this->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN2
             or $this->aggregation == GRADE_AGGREGATE_EXTRACREDIT_MEAN
             or $this->aggregation == GRADE_AGGREGATE_SUM);

    }

    public function get_coefstring($first=true) {
        if (!is_null($this->coefstring)) {
            return $this->coefstring;
        }

        $overriding_coefstring = null;

        // Stop recursing upwards if this category aggregates subcats or has no parent
        if (!$first && !$this->aggregatesubcats) {

            if ($parent_category = $this->load_parent_category()) {
                return $parent_category->get_coefstring(false);

            } else {
                return null;
            }

        } else if ($first) {

            if (!$this->aggregatesubcats) {

                if ($parent_category = $this->load_parent_category()) {
                    $overriding_coefstring = $parent_category->get_coefstring(false);
                }
            }
        }

        // If an overriding coefstring has trickled down from one of the parent categories, return it. Otherwise, return self.
        if (!is_null($overriding_coefstring)) {
            return $overriding_coefstring;
        }

        // No parent category is overriding this category's aggregation, return its string
        if ($this->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN) {
            $this->coefstring = 'aggregationcoefweight';

        } else if ($this->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN2) {
            $this->coefstring = 'aggregationcoefextrasum';

        } else if ($this->aggregation == GRADE_AGGREGATE_EXTRACREDIT_MEAN) {
            $this->coefstring = 'aggregationcoefextraweight';

        } else if ($this->aggregation == GRADE_AGGREGATE_SUM) {
            $this->coefstring = 'aggregationcoefextrasum';

        } else {
            $this->coefstring = 'aggregationcoef';
        }
        return $this->coefstring;
    }

    public static function fetch_course_tree($courseid, $include_category_items=false) {
        $course_category = grade_category::fetch_course_category($courseid);
        $category_array = array('object'=>$course_category, 'type'=>'category', 'depth'=>1,
                                'children'=>$course_category->get_children($include_category_items));

        $course_category->sortorder = $course_category->get_sortorder();
        return grade_category::_fetch_course_tree_recursion($category_array, $course_category->get_sortorder());
    }

    static private function _fetch_course_tree_recursion($category_array, &$sortorder) {
        // update the sortorder in db if needed
        //NOTE: This leads to us resetting sort orders every time the categories and items page is viewed :(
        //if ($category_array['object']->sortorder != $sortorder) {
            //$category_array['object']->set_sortorder($sortorder);
        //}

        if (isset($category_array['object']->gradetype) && $category_array['object']->gradetype==GRADE_TYPE_NONE) {
            return null;
        }

        // store the grade_item or grade_category instance with extra info
        $result = array('object'=>$category_array['object'], 'type'=>$category_array['type'], 'depth'=>$category_array['depth']);

        // reuse final grades if there
        if (array_key_exists('finalgrades', $category_array)) {
            $result['finalgrades'] = $category_array['finalgrades'];
        }

        // recursively resort children
        if (!empty($category_array['children'])) {
            $result['children'] = array();
            //process the category item first
            $child = null;

            foreach ($category_array['children'] as $oldorder=>$child_array) {

                if ($child_array['type'] == 'courseitem' or $child_array['type'] == 'categoryitem') {
                    $child = grade_category::_fetch_course_tree_recursion($child_array, $sortorder);
                    if (!empty($child)) {
                        $result['children'][$sortorder] = $child;
                    }
                }
            }

            foreach ($category_array['children'] as $oldorder=>$child_array) {

                if ($child_array['type'] != 'courseitem' and $child_array['type'] != 'categoryitem') {
                    $child = grade_category::_fetch_course_tree_recursion($child_array, $sortorder);
                    if (!empty($child)) {
                        $result['children'][++$sortorder] = $child;
                    }
                }
            }
        }

        return $result;
    }

    public function get_children($include_category_items=false) {
        global $DB;

        // This function must be as fast as possible ;-)
        // fetch all course grade items and categories into memory - we do not expect hundreds of these in course
        // we have to limit the number of queries though, because it will be used often in grade reports

        $cats  = $DB->get_records('grade_categories', array('courseid' => $this->courseid));
        $items = $DB->get_records('grade_items', array('courseid' => $this->courseid));

        // init children array first
        foreach ($cats as $catid=>$cat) {
            $cats[$catid]->children = array();
        }

        //first attach items to cats and add category sortorder
        foreach ($items as $item) {

            if ($item->itemtype == 'course' or $item->itemtype == 'category') {
                $cats[$item->iteminstance]->sortorder = $item->sortorder;

                if (!$include_category_items) {
                    continue;
                }
                $categoryid = $item->iteminstance;

            } else {
                $categoryid = $item->categoryid;
            }

            // prevent problems with duplicate sortorders in db
            $sortorder = $item->sortorder;

            while (array_key_exists($sortorder, $cats[$categoryid]->children)) {
                //debugging("$sortorder exists in item loop");
                $sortorder++;
            }

            $cats[$categoryid]->children[$sortorder] = $item;

        }

        // now find the requested category and connect categories as children
        $category = false;

        foreach ($cats as $catid=>$cat) {

            if (empty($cat->parent)) {

                if ($cat->path !== '/'.$cat->id.'/') {
                    $grade_category = new grade_category($cat, false);
                    $grade_category->path  = '/'.$cat->id.'/';
                    $grade_category->depth = 1;
                    $grade_category->update('system');
                    return $this->get_children($include_category_items);
                }

            } else {

                if (empty($cat->path) or !preg_match('|/'.$cat->parent.'/'.$cat->id.'/$|', $cat->path)) {
                    //fix paths and depts
                    static $recursioncounter = 0; // prevents infinite recursion
                    $recursioncounter++;

                    if ($recursioncounter < 5) {
                        // fix paths and depths!
                        $grade_category = new grade_category($cat, false);
                        $grade_category->depth = 0;
                        $grade_category->path  = null;
                        $grade_category->update('system');
                        return $this->get_children($include_category_items);
                    }
                }
                // prevent problems with duplicate sortorders in db
                $sortorder = $cat->sortorder;

                while (array_key_exists($sortorder, $cats[$cat->parent]->children)) {
                    //debugging("$sortorder exists in cat loop");
                    $sortorder++;
                }

                $cats[$cat->parent]->children[$sortorder] = &$cats[$catid];
            }

            if ($catid == $this->id) {
                $category = &$cats[$catid];
            }
        }

        unset($items); // not needed
        unset($cats); // not needed

        $children_array = grade_category::_get_children_recursion($category);

        ksort($children_array);

        return $children_array;

    }

    private static function _get_children_recursion($category) {

        $children_array = array();
        foreach ($category->children as $sortorder=>$child) {

            if (array_key_exists('itemtype', $child)) {
                $grade_item = new grade_item($child, false);

                if (in_array($grade_item->itemtype, array('course', 'category'))) {
                    $type  = $grade_item->itemtype.'item';
                    $depth = $category->depth;

                } else {
                    $type  = 'item';
                    $depth = $category->depth; // we use this to set the same colour
                }
                $children_array[$sortorder] = array('object'=>$grade_item, 'type'=>$type, 'depth'=>$depth);

            } else {
                $children = grade_category::_get_children_recursion($child);
                $grade_category = new grade_category($child, false);

                if (empty($children)) {
                    $children = array();
                }
                $children_array[$sortorder] = array('object'=>$grade_category, 'type'=>'category', 'depth'=>$grade_category->depth, 'children'=>$children);
            }
        }

        // sort the array
        ksort($children_array);

        return $children_array;
    }

    public function load_grade_item() {
        if (empty($this->grade_item)) {
            $this->grade_item = $this->get_grade_item();
        }
        return $this->grade_item;
    }

    public function get_grade_item() {
        if (empty($this->id)) {
            debugging("Attempt to obtain a grade_category's associated grade_item without the category's ID being set.");
            return false;
        }

        if (empty($this->parent)) {
            $params = array('courseid'=>$this->courseid, 'itemtype'=>'course', 'iteminstance'=>$this->id);

        } else {
            $params = array('courseid'=>$this->courseid, 'itemtype'=>'category', 'iteminstance'=>$this->id);
        }

        if (!$grade_items = grade_item::fetch_all($params)) {
            // create a new one
            $grade_item = new grade_item($params, false);
            $grade_item->gradetype = GRADE_TYPE_VALUE;
            $grade_item->insert('system');

        } else if (count($grade_items) == 1) {
            // found existing one
            $grade_item = reset($grade_items);

        } else {
            debugging("Found more than one grade_item attached to category id:".$this->id);
            // return first one
            $grade_item = reset($grade_items);
        }

        return $grade_item;
    }

    public function load_parent_category() {
        if (empty($this->parent_category) && !empty($this->parent)) {
            $this->parent_category = $this->get_parent_category();
        }
        return $this->parent_category;
    }

    public function get_parent_category() {
        if (!empty($this->parent)) {
            $parent_category = new grade_category(array('id' => $this->parent));
            return $parent_category;
        } else {
            return null;
        }
    }

    public function get_name() {
        global $DB;
        // For a course category, we return the course name if the fullname is set to '?' in the DB (empty in the category edit form)
        if (empty($this->parent) && $this->fullname == '?') {
            $course = $DB->get_record('course', array('id'=> $this->courseid));
            return format_string($course->fullname);

        } else {
            return $this->fullname;
        }
    }

    public function set_parent($parentid, $source=null) {
        if ($this->parent == $parentid) {
            return true;
        }

        if ($parentid == $this->id) {
            print_error('cannotassignselfasparent');
        }

        if (empty($this->parent) and $this->is_course_category()) {
            print_error('cannothaveparentcate');
        }

        // find parent and check course id
        if (!$parent_category = grade_category::fetch(array('id'=>$parentid, 'courseid'=>$this->courseid))) {
            return false;
        }

        $this->force_regrading();

        // set new parent category
        $this->parent          = $parent_category->id;
        $this->parent_category =& $parent_category;
        $this->path            = null;       // remove old path and depth - will be recalculated in update()
        $this->depth           = 0;          // remove old path and depth - will be recalculated in update()
        $this->update($source);

        return $this->update($source);
    }

    public function get_final($userid=null) {
        $this->load_grade_item();
        return $this->grade_item->get_final($userid);
    }

    public function get_sortorder() {
        $this->load_grade_item();
        return $this->grade_item->get_sortorder();
    }

    public function get_idnumber() {
        $this->load_grade_item();
        return $this->grade_item->get_idnumber();
    }

    public function set_sortorder($sortorder) {
        $this->load_grade_item();
        $this->grade_item->set_sortorder($sortorder);
    }

    public function move_after_sortorder($sortorder) {
        $this->load_grade_item();
        $this->grade_item->move_after_sortorder($sortorder);
    }

    public function is_course_category() {
        $this->load_grade_item();
        return $this->grade_item->is_course_item();
    }

    public static function fetch_course_category($courseid) {
        if (empty($courseid)) {
            debugging('Missing course id!');
            return false;
        }

        // course category has no parent
        if ($course_category = grade_category::fetch(array('courseid'=>$courseid, 'parent'=>null))) {
            return $course_category;
        }

        // create a new one
        $course_category = new grade_category();
        $course_category->insert_course_category($courseid);

        return $course_category;
    }

    public function is_editable() {
        return true;
    }

    public function is_locked() {
        $this->load_grade_item();
        return $this->grade_item->is_locked();
    }

    public function set_locked($lockedstate, $cascade=false, $refresh=true) {
        $this->load_grade_item();

        $result = $this->grade_item->set_locked($lockedstate, $cascade, true);

        if ($cascade) {
            //process all children - items and categories
            if ($children = grade_item::fetch_all(array('categoryid'=>$this->id))) {

                foreach ($children as $child) {
                    $child->set_locked($lockedstate, true, false);

                    if (empty($lockedstate) and $refresh) {
                        //refresh when unlocking
                        $child->refresh_grades();
                    }
                }
            }

            if ($children = grade_category::fetch_all(array('parent'=>$this->id))) {

                foreach ($children as $child) {
                    $child->set_locked($lockedstate, true, true);
                }
            }
        }

        return $result;
    }

    public static function set_properties(&$instance, $params) {
        global $DB;

        parent::set_properties($instance, $params);

        //if they've changed aggregation type we made need to do some fiddling to provide appropriate defaults
        if (!empty($params->aggregation)) {

            //weight and extra credit share a column :( Would like a default of 1 for weight and 0 for extra credit
            //Flip from the default of 0 to 1 (or vice versa) if ALL items in the category are still set to the old default.
            if ($params->aggregation==GRADE_AGGREGATE_WEIGHTED_MEAN || $params->aggregation==GRADE_AGGREGATE_EXTRACREDIT_MEAN) {
                $sql = $defaultaggregationcoef = null;

                if ($params->aggregation==GRADE_AGGREGATE_WEIGHTED_MEAN) {
                    //if all items in this category have aggregation coefficient of 0 we can change it to 1 ie evenly weighted
                    $sql = "select count(id) from {grade_items} where categoryid=:categoryid and aggregationcoef!=0";
                    $defaultaggregationcoef = 1;
                } else if ($params->aggregation==GRADE_AGGREGATE_EXTRACREDIT_MEAN) {
                    //if all items in this category have aggregation coefficient of 1 we can change it to 0 ie no extra credit
                    $sql = "select count(id) from {grade_items} where categoryid=:categoryid and aggregationcoef!=1";
                    $defaultaggregationcoef = 0;
                }

                $params = array('categoryid'=>$instance->id);
                $count = $DB->count_records_sql($sql, $params);
                if ($count===0) { //category is either empty or all items are set to a default value so we can switch defaults
                    $params['aggregationcoef'] = $defaultaggregationcoef;
                    $DB->execute("update {grade_items} set aggregationcoef=:aggregationcoef where categoryid=:categoryid",$params);
                }
            }
        }
    }

    public function set_hidden($hidden, $cascade=false) {
        $this->load_grade_item();
        //this hides the associated grade item (the course total)
        $this->grade_item->set_hidden($hidden, $cascade);
        //this hides the category itself and everything it contains
        parent::set_hidden($hidden, $cascade);

        if ($cascade) {

            if ($children = grade_item::fetch_all(array('categoryid'=>$this->id))) {

                foreach ($children as $child) {
                    $child->set_hidden($hidden, $cascade);
                }
            }

            if ($children = grade_category::fetch_all(array('parent'=>$this->id))) {

                foreach ($children as $child) {
                    $child->set_hidden($hidden, $cascade);
                }
            }
        }

        //if marking category visible make sure parent category is visible MDL-21367
        if( !$hidden ) {
            $category_array = grade_category::fetch_all(array('id'=>$this->parent));
            if ($category_array && array_key_exists($this->parent, $category_array)) {
                $category = $category_array[$this->parent];
                //call set_hidden on the category regardless of whether it is hidden as its parent might be hidden
                //if($category->is_hidden()) {
                    $category->set_hidden($hidden, false);
                //}
            }
        }
    }

    public function apply_default_settings() {
        global $CFG;

        foreach ($this->forceable as $property) {

            if (isset($CFG->{"grade_$property"})) {

                if ($CFG->{"grade_$property"} == -1) {
                    continue; //temporary bc before version bump
                }
                $this->$property = $CFG->{"grade_$property"};
            }
        }
    }

    public function apply_forced_settings() {
        global $CFG;

        $updated = false;

        foreach ($this->forceable as $property) {

            if (isset($CFG->{"grade_$property"}) and isset($CFG->{"grade_{$property}_flag"}) and
                                                    ((int) $CFG->{"grade_{$property}_flag"} & 1)) {

                if ($CFG->{"grade_$property"} == -1) {
                    continue; //temporary bc before version bump
                }
                $this->$property = $CFG->{"grade_$property"};
                $updated = true;
            }
        }

        return $updated;
    }

    public static function updated_forced_settings() {
        global $CFG, $DB;
        $params = array(1, 'course', 'category');
        $sql = "UPDATE {grade_items} SET needsupdate=? WHERE itemtype=? or itemtype=?";
        $DB->execute($sql, $params);
    }
}