<?php // $Id$
/**
 * File in which the grader_report class is defined.
 * @package gradebook
 */

require_once($CFG->dirroot . '/grade/report/lib.php');
require_once($CFG->libdir.'/tablelib.php');

/**
 * Class providing an API for the grader report building and displaying.
 * @uses grade_report
 * @package gradebook
 */
class grade_report_grader extends grade_report {
    /**
     * The final grades.
     * @var array $finalgrades
     */
    var $finalgrades;

    /**
     * The grade items.
     * @var array $items
     */
    var $items;

    /**
     * Array of errors for bulk grades updating.
     * @var array $gradeserror
     */
    var $gradeserror = array();

//// SQL-RELATED

    /**
     * The id of the grade_item by which this report will be sorted.
     * @var int $sortitemid
     */
    var $sortitemid;

    /**
     * Sortorder used in the SQL selections.
     * @var int $sortorder
     */
    var $sortorder;

    /**
     * An SQL fragment affecting the search for users.
     * @var string $userselect
     */
    var $userselect;

    /**
     * Constructor. Sets local copies of user preferences and initialises grade_tree.
     * @param int $courseid
     * @param object $gpr grade plugin return tracking object
     * @param string $context
     * @param int $page The current page being viewed (when report is paged)
     * @param int $sortitemid The id of the grade_item by which to sort the table
     */
    function grade_report_grader($courseid, $gpr, $context, $page=null, $sortitemid=null) {
        global $CFG;
        parent::grade_report($courseid, $gpr, $context, $page);

        $this->sortitemid = $sortitemid;

        // base url for sorting by first/last name
        $this->baseurl = 'index.php?id='.$this->courseid.'&amp;perpage='.$this->get_pref('studentsperpage')
                        .'&amp;page='.$this->page;
        //
        $this->pbarurl = 'index.php?id='.$this->courseid.'&amp;perpage='.$this->get_pref('studentsperpage');

        // Setup groups if requested
        if ($this->get_pref('showgroups')) {
            $this->setup_groups();
        }

        $this->setup_sortitemid();
    }

    /**
     * Processes the data sent by the form (grades and feedbacks).
     * @var array $data
     * @return bool Success or Failure (array of errors).
     */
    function process_data($data) {

        if (!has_capability('moodle/grade:override', $this->context)) {
            return false;
        }

        // always initialize all arrays
        $queue = array();
        foreach ($data as $varname => $postedvalue) {

            $needsupdate = false;
            $note = false; // TODO implement note??

            // skip, not a grade nor feedback
            if (strpos($varname, 'grade') === 0) {
                $data_type = 'grade';
            } else if (strpos($varname, 'feedback') === 0) {
                $data_type = 'feedback';
            } else {
                continue;
            }

            $gradeinfo = explode("_", $varname);
            $userid = clean_param($gradeinfo[1], PARAM_INT);
            $itemid = clean_param($gradeinfo[2], PARAM_INT);

            $oldvalue = $data->{'old'.$varname};

            // was change requested?
            if ($oldvalue == $postedvalue) {
                continue;
            }

            if (!$grade_item = grade_item::fetch(array('id'=>$itemid, 'courseid'=>$this->courseid))) { // we must verify course id here!
                error('Incorrect grade item id');
            }

            // Pre-process grade
            if ($data_type == 'grade') {
                $feedback = false;
                $feedbackformat = false;
                if ($grade_item->gradetype == GRADE_TYPE_SCALE) {
                    if ($postedvalue == -1) { // -1 means no grade
                        $finalgrade = null;
                    } else {
                        $finalgrade = $postedvalue;
                    }
                } else {
                    $trimmed = trim($postedvalue);
                    if (empty($trimmed)) { // empty string means no grade
                        $finalgrade = null;
                    } else {
                        $finalgrade = $this->format_grade($postedvalue);
                    }
                }

            } else if ($data_type == 'feedback') {
                $finalgrade = false;
                $trimmed = trim($postedvalue);
                if (empty($trimmed)) {
                     $feedback = NULL;
                } else {
                     $feedback = stripslashes($postedvalue);
                }
            }

            $grade_item->update_final_grade($userid, $finalgrade, 'gradebook', $note, $feedback);
        }

        return true;
    }


    /**
     * Setting the sort order, this depends on last state
     * all this should be in the new table class that we might need to use
     * for displaying grades.
     */
    function setup_sortitemid() {

        global $SESSION;

        if ($this->sortitemid) {
            if (!isset($SESSION->gradeuserreport->sort)) {
                $this->sortorder = $SESSION->gradeuserreport->sort = 'ASC';
            } else {
                // this is the first sort, i.e. by last name
                if (!isset($SESSION->gradeuserreport->sortitemid)) {
                    $this->sortorder = $SESSION->gradeuserreport->sort = 'ASC';
                } else if ($SESSION->gradeuserreport->sortitemid == $this->sortitemid) {
                    // same as last sort
                    if ($SESSION->gradeuserreport->sort == 'ASC') {
                        $this->sortorder = $SESSION->gradeuserreport->sort = 'DESC';
                    } else {
                        $this->sortorder = $SESSION->gradeuserreport->sort = 'ASC';
                    }
                } else {
                    $this->sortorder = $SESSION->gradeuserreport->sort = 'ASC';
                }
            }
            $SESSION->gradeuserreport->sortitemid = $this->sortitemid;
        } else {
            // not requesting sort, use last setting (for paging)

            if (isset($SESSION->gradeuserreport->sortitemid)) {
                $this->sortitemid = $SESSION->gradeuserreport->sortitemid;
            }
            if (isset($SESSION->gradeuserreport->sort)) {
                $this->sortorder = $SESSION->gradeuserreport->sort;
            } else {
                $this->sortorder = 'ASC';
            }
        }
    }

    /**
     * pulls out the userids of the users to be display, and sort them
     * the right outer join is needed because potentially, it is possible not
     * to have the corresponding entry in grade_grades table for some users
     * this is check for user roles because there could be some users with grades
     * but not supposed to be displayed
     */
    function load_users() {
        global $CFG;

        if (is_numeric($this->sortitemid)) {
            $sql = "SELECT u.id, u.firstname, u.lastname
                    FROM {$CFG->prefix}grade_grades g RIGHT OUTER JOIN
                         {$CFG->prefix}user u ON (u.id = g.userid AND g.itemid = $this->sortitemid)
                         LEFT JOIN {$CFG->prefix}role_assignments ra ON u.id = ra.userid
                         $this->groupsql
                    WHERE ra.roleid in ($this->gradebookroles)
                         $this->groupwheresql
                    AND ra.contextid ".get_related_contexts_string($this->context)."
                    ORDER BY g.finalgrade $this->sortorder";
            $this->users = get_records_sql($sql, $this->get_pref('studentsperpage') * $this->page,
                                $this->get_pref('studentsperpage'));
        } else {
            // default sort
            // get users sorted by lastname
            $this->users = get_role_users(@implode(',', $CFG->gradebookroles), $this->context, false,
                                'u.id, u.firstname, u.lastname', 'u.'.$this->sortitemid .' '. $this->sortorder,
                                false, $this->page * $this->get_pref('studentsperpage'), $this->get_pref('studentsperpage'),
                                $this->currentgroup);
            // need to cut users down by groups

        }

        if (empty($this->users)) {
            $this->userselect = '';
            $this->users = array();
        } else {
            $this->userselect = 'AND g.userid in ('.implode(',', array_keys($this->users)).')';
        }

        return $this->users;
    }

    /**
     * Fetches and returns a count of all the users that will be shown on this page.
     * @return int Count of users
     */
    function get_numusers() {
        global $CFG;

        $countsql = "SELECT COUNT(DISTINCT u.id)
                    FROM {$CFG->prefix}grade_grades g RIGHT OUTER JOIN
                         {$CFG->prefix}user u ON (u.id = g.userid AND g.itemid = $this->sortitemid)
                         LEFT JOIN {$CFG->prefix}role_assignments ra ON u.id = ra.userid
                         $this->groupsql
                    WHERE ra.roleid in ($this->gradebookroles)
                         $this->groupwheresql
                    AND ra.contextid ".get_related_contexts_string($this->context);
        return count_records_sql($countsql);
    }

    /**
     * we supply the userids in this query, and get all the grades
     * pulls out all the grades, this does not need to worry about paging
     */
    function load_final_grades() {
        global $CFG;

        // please note that we must fetch all grade_grades fields if we want to contruct grade_grade object from it!
        $sql = "SELECT g.*, gt.feedback, gt.feedbackformat, gi.grademin, gi.grademax
                  FROM {$CFG->prefix}grade_items gi,
                       {$CFG->prefix}grade_grades g
                       LEFT JOIN {$CFG->prefix}grade_grades_text gt ON g.id = gt.gradeid
                 WHERE g.itemid = gi.id AND gi.courseid = $this->courseid $this->userselect";

        if ($grades = get_records_sql($sql)) {
            foreach ($grades as $grade) {
                $this->finalgrades[$grade->userid][$grade->itemid] = $grade;
            }
        }
    }

    /**
     * Builds and returns a div with on/off toggles.
     * @return string HTML code
     */
    function get_toggles_html() {
        global $USER;
        $html = '<div id="grade-report-toggles">';
        if ($USER->gradeediting[$this->courseid]) {
            if (has_capability('moodle/grade:manage', $this->context) or has_capability('moodle/grade:hide', $this->context)) {
                $html .= $this->print_toggle('eyecons', true);
            }
            if (has_capability('moodle/grade:manage', $this->context)
             or has_capability('moodle/grade:lock', $this->context)
             or has_capability('moodle/grade:unlock', $this->context)) {
                $html .= $this->print_toggle('locks', true);
            }
            if (has_capability('moodle/grade:manage', $this->context)) {
                $html .= $this->print_toggle('calculations', true);
            }
        }

        $html .= $this->print_toggle('averages', true);
        $html .= $this->print_toggle('groups', true);
        $html .= $this->print_toggle('ranges', true);
        $html .= '</div>';
        return $html;
    }

    /**
    * Shortcut function for printing the grader report toggles.
    * @param string $type The type of toggle
    * @param bool $return Whether to return the HTML string rather than printing it
    * @return void
    */
    function print_toggle($type, $return=false) {
        global $CFG;

        $icons = array('eyecons' => 'hide',
                       'calculations' => 'calc',
                       'locks' => 'lock',
                       'averages' => 'sigma');

        $pref_name = 'grade_report_show' . $type;
        $show_pref = get_user_preferences($pref_name, $CFG->$pref_name);

        $strshow = $this->get_lang_string('show' . $type, 'grades');
        $strhide = $this->get_lang_string('hide' . $type, 'grades');

        $show_hide = 'show';
        $toggle_action = 1;

        if ($show_pref) {
            $show_hide = 'hide';
            $toggle_action = 0;
        }

        if (array_key_exists($type, $icons)) {
            $image_name = $icons[$type];
        } else {
            $image_name = $type;
        }

        $string = ${'str' . $show_hide};

        $img = '<img src="'.$CFG->pixpath.'/t/'.$image_name.'.gif" class="iconsmall" alt="'
                      .$string.'" title="'.$string.'" />'. "\n";

        $retval = '<div class="gradertoggle">' . $img . '<a href="' . $this->baseurl . "&amp;toggle=$toggle_action&amp;toggle_type=$type\">"
             . $string . '</a></div>';

        if ($return) {
            return $retval;
        } else {
            echo $retval;
        }
    }

    /**
     * Builds and returns the HTML code for the headers.
     * @return string $headerhtml
     */
    function get_headerhtml() {
        global $CFG, $USER;

        $strsortasc   = $this->get_lang_string('sortasc', 'grades');
        $strsortdesc  = $this->get_lang_string('sortdesc', 'grades');
        $strfirstname = $this->get_lang_string('firstname');
        $strlastname  = $this->get_lang_string('lastname');

        if ($this->sortitemid === 'lastname') {
            if ($this->sortorder == 'ASC') {
                $lastarrow = print_arrow('up', $strsortasc, true);
            } else {
                $lastarrow = print_arrow('down', $strsortdesc, true);
            }
        } else {
            $lastarrow = '';
        }

        if ($this->sortitemid === 'firstname') {
            if ($this->sortorder == 'ASC') {
                $firstarrow = print_arrow('up', $strsortasc, true);
            } else {
                $firstarrow = print_arrow('down', $strsortdesc, true);
            }
        } else {
            $firstarrow = '';
        }
        // Prepare Table Headers
        $headerhtml = '';

        $numrows = count($this->gtree->levels);

        $columns_to_unset = array();

        foreach ($this->gtree->levels as $key=>$row) {
            if ($key == 0) {
                // do not display course grade category
                // continue;
            }

            $headerhtml .= '<tr class="heading">';

            if ($key == $numrows - 1) {
                $headerhtml .= '<th class="user"><a href="'.$this->baseurl.'&amp;sortitemid=firstname">' . $strfirstname . '</a> ' //TODO: localize
                            . $firstarrow. '/ <a href="'.$this->baseurl.'&amp;sortitemid=lastname">' . $strlastname . '</a>'. $lastarrow .'</th>';
            } else {
                $headerhtml .= '<td class="topleft">&nbsp;</td>';
            }

            foreach ($row as $columnkey => $element) {
                $eid    = $element['eid'];
                $object = $element['object'];
                $type   = $element['type'];
                $categorystate = @$element['categorystate'];

                if (!empty($element['colspan'])) {
                    $colspan = 'colspan="'.$element['colspan'].'"';
                } else {
                    $colspan = '';
                }

                if (!empty($element['depth'])) {
                    $catlevel = ' catlevel'.$element['depth'];
                } else {
                    $catlevel = '';
                }

// Element is a filler
                if ($type == 'filler' or $type == 'fillerfirst' or $type == 'fillerlast') {
                    $headerhtml .= '<th class="'.$type.$catlevel.'" '.$colspan.'>&nbsp;</th>';
                }
// Element is a category
                else if ($type == 'category' && !in_array($eid, $columns_to_unset)) {
                    $headerhtml .= '<th class="category'.$catlevel.'" '.$colspan.'>'.$element['object']->get_name();

                    // Print icons
                    if ($USER->gradeediting[$this->courseid]) {
                        $headerhtml .= $this->get_icons($element);
                    }

                    $headerhtml .= '</th>';
                }
// Element is a grade_item
                elseif (!in_array($eid, $columns_to_unset)) {
                    if ($element['object']->id == $this->sortitemid) {
                        if ($this->sortorder == 'ASC') {
                            $arrow = print_arrow('up', $strsortasc, true);
                        } else {
                            $arrow = print_arrow('down', $strsortdesc, true);
                        }
                    } else {
                        $arrow = '';
                    }

                    $dimmed = '';
                    if ($element['object']->is_hidden()) {
                        $dimmed = ' dimmed_text ';
                    }

                    if ($object->itemtype == 'mod') {
                        $icon = '<img src="'.$CFG->modpixpath.'/'.$object->itemmodule.'/icon.gif" class="icon" alt="'
                              .$this->get_lang_string('modulename', $object->itemmodule).'"/>';
                    } else if ($object->itemtype == 'manual') {
                        //TODO: add manual grading icon
                        $icon = '<img src="'.$CFG->pixpath.'/t/edit.gif" class="icon" alt="'.$this->get_lang_string('manualgrade', 'grades')
                              .'"/>';
                    }


                    $headerhtml .= '<th class="'.$type.$catlevel.$dimmed.'"><a href="'.$this->baseurl.'&amp;sortitemid='
                              . $element['object']->id .'">'. $element['object']->get_name()
                              . '</a>' . $arrow;

                    $headerhtml .= $this->get_icons($element) . '</th>';

                    $this->items[$element['object']->sortorder] =& $element['object'];
                }

            }

            $headerhtml .= '</tr>';
        }
        return $headerhtml;
    }

    /**
     * Builds and return the HTML rows of the table (grades headed by student).
     * @return string HTML
     */
    function get_studentshtml() {
        global $CFG, $USER;
        $studentshtml = '';
        $strfeedback = $this->get_lang_string("feedback");
        $gradetabindex = 1;
        $showuserimage = $this->get_pref('showuserimage');
        $numusers = count($this->users);

        // Preload scale objects for items with a scaleid
        $scales_list = '';
        $tabindices = array();
        foreach ($this->items as $item) {
            if (!empty($item->scaleid)) {
                $scales_list .= "$item->scaleid,";
            }
            $tabindices[$item->id]['grade'] = $gradetabindex;
            $tabindices[$item->id]['feedback'] = $gradetabindex + $numusers;
            $gradetabindex += $numusers * 2;
        }
        $scales_array = array();

        if (!empty($scales_list)) {
            $scales_list = substr($scales_list, 0, -1);
            $scales_array = get_records_list('scale', 'id', $scales_list);
        }

        foreach ($this->users as $userid => $user) {
            // Student name and link
            $user_pic = null;
            if ($showuserimage) {
                $user_pic = '<div class="userpic">' . print_user_picture($user->id, $this->courseid, true, 0, true) . '</div>';
            }

            $studentshtml .= '<tr><th class="user">' . $user_pic . '<a href="' . $CFG->wwwroot . '/user/view.php?id='
                          . $user->id . '">' . fullname($user) . '</a></th>';

            foreach ($this->items as $itemid=>$item) {
                // Get the decimal points preference for this item
                $decimalpoints = $this->get_pref('decimalpoints', $item->id);

                if (isset($this->finalgrades[$userid][$item->id])) {
                    $gradeval = $this->finalgrades[$userid][$item->id]->finalgrade;

                    $grade = new grade_grade($this->finalgrades[$userid][$item->id], false);
                    $grade->feedback = stripslashes_safe($this->finalgrades[$userid][$item->id]->feedback);
                    $grade->feedbackformat = $this->finalgrades[$userid][$item->id]->feedbackformat;

                } else {
                    $gradeval = null;
                    $grade = new grade_grade(array('userid'=>$userid, 'itemid'=>$item->id), false);
                    $grade->feedback = '';
                }

                $grade->courseid = $this->courseid;
                $grade->grade_item =& $this->items[$itemid]; // this speedsup is_hidden() and other grade_grade methods

                // emulate grade element
                $element = array('eid'=>'g'.$grade->id, 'object'=>$grade, 'type'=>'grade');

                if ($grade->is_overridden()) {
                    $studentshtml .= '<td class="overridden">';
                } else {
                    $studentshtml .= '<td>';
                }

                if ($grade->is_excluded()) {
                    $studentshtml .= get_string('excluded', 'grades'); // TODO: improve visual representation of excluded grades
                }

                // Do not show any icons if no grade (no record in DB to match)
                // TODO: change edit/hide/etc. links to use itemid and userid to allow creating of new grade objects
                if (!$item->needsupdate and !empty($grade->id) and $USER->gradeediting[$this->courseid]) {
                    $studentshtml .= $this->get_icons($element);
                }

                // if in editting mode, we need to print either a text box
                // or a drop down (for scales)
                // grades in item of type grade category or course are not directly editable
                if ($item->needsupdate) {
                    $studentshtml .= '<span class="gradingerror">'.get_string('error').'</span>';

                } else if ($USER->gradeediting[$this->courseid]) {
                    // We need to retrieve each grade_grade object from DB in order to
                    // know if they are hidden/locked

                    if ($item->scaleid && !empty($scales_array[$item->scaleid])) {
                        $scale = $scales_array[$item->scaleid];

                        $scales = explode(",", $scale->scale);
                        // reindex because scale is off 1
                        $i = 0;
                        foreach ($scales as $scaleoption) {
                            $i++;
                            $scaleopt[$i] = $scaleoption;
                        }

                        if ($this->get_pref('quickgrading') and $grade->is_editable()) {
                            $studentshtml .= '<input type="hidden" name="oldgrade_'.$userid.'_'
                                          .$item->id.'" value="'.$gradeval.'"/>';
                            $studentshtml .= choose_from_menu($scaleopt, 'grade_'.$userid.'_'.$item->id,
                                                              $gradeval, $this->get_lang_string('nograde'), '', '-1',
                                                              true, false, $tabindices[$item->id]['grade']);
                        } elseif(!empty($scale)) {
                            $scales = explode(",", $scale->scale);

                            // invalid grade if gradeval < 1
                            if ((int) $gradeval < 1) {
                                $studentshtml .= '-';
                            } else {
                                $studentshtml .= $scales[$gradeval-1];
                            }
                        } else {
                            // no such scale, throw error?
                        }

                    } else if ($item->gradetype != GRADE_TYPE_TEXT) { // Value type
                        if ($this->get_pref('quickgrading') and $grade->is_editable()) {
                            $value = $this->get_grade_clean($gradeval, $decimalpoints);
                            $studentshtml .= '<input type="hidden" name="oldgrade_'.$userid.'_'.$item->id.'" value="'.$value.'" />';
                            $studentshtml .= '<input size="6" tabindex="' . $tabindices[$item->id]['grade'] . '" type="text" name="grade_'
                                          .$userid.'_' .$item->id.'" value="'.$value.'" />';
                        } else {
                            $studentshtml .= $this->get_grade_clean($gradeval, $decimalpoints);
                        }
                    }


                    // If quickfeedback is on, print an input element
                    if ($this->get_pref('quickfeedback') and $grade->is_editable()) {
                        if ($this->get_pref('quickgrading')) {
                            $studentshtml .= '<br />';
                        }
                        $studentshtml .= '<input type="hidden" name="oldfeedback_'
                                      .$userid.'_'.$item->id.'" value="' . s($grade->feedback) . '" />';
                        $studentshtml .= '<input tabindex="' . $tabindices[$item->id]['feedback'] . '" size="6" type="text" name="feedback_'
                                      .$userid.'_'.$item->id.'" value="' . s($grade->feedback) . '" />';
                    }

                } else {
                    // Percentage format if specified by user (check each item for a set preference)
                    $gradedisplaytype = $this->get_pref('gradedisplaytype', $item->id);

                    $percentsign = '';
                    $grademin = $item->grademin;
                    $grademax = $item->grademax;

                    if ($gradedisplaytype == GRADE_REPORT_GRADE_DISPLAY_TYPE_PERCENTAGE) {
                        if (!is_null($gradeval)) {
                            $gradeval = grade_grade::standardise_score($gradeval, $grademin, $grademax, 0, 100);
                        }
                        $percentsign = '%';
                    }

                    // If feedback present, surround grade with feedback tooltip
                    if (!empty($grade->feedback)) {
                        if ($grade->feedbackformat == 1) {
                            $overlib = "return overlib('" . s(ltrim($grade->feedback)) . "', FULLHTML);";
                        } else {
                            $overlib = "return overlib('" . ($grade->feedback) . "', CAPTION, '$strfeedback');";
                        }

                        $studentshtml .= '<span onmouseover="' . $overlib . '" onmouseout="return nd();">';
                    }

                    if ($item->needsupdate) {
                        $studentshtml .= '<span class="gradingerror">'.get_string('error').'</span>';

                    } else if ($gradedisplaytype == GRADE_REPORT_GRADE_DISPLAY_TYPE_LETTER) {
                        $letters = grade_report::get_grade_letters();
                        if (!is_null($gradeval)) {
                            $studentshtml .= grade_grade::get_letter($letters, $gradeval, $grademin, $grademax);
                        }
                    } else if ($item->scaleid && !empty($scales_array[$item->scaleid])
                                && $gradedisplaytype == GRADE_REPORT_GRADE_DISPLAY_TYPE_REAL) {
                        $scale = $scales_array[$item->scaleid];
                        $scales = explode(",", $scale->scale);

                        // invalid grade if gradeval < 1
                        if ((int) $gradeval < 1) {
                            $studentshtml .= '-';
                        } else {
                            $studentshtml .= $scales[$gradeval-1];
                        }
                    } else {
                        if (is_null($gradeval)) {
                            $studentshtml .= '-';
                        } else {
                            $studentshtml .=  $this->get_grade_clean($gradeval, $decimalpoints). $percentsign;
                        }
                    }
                    if (!empty($grade->feedback)) {
                        $studentshtml .= '</span>';
                    }
                }

                if (!empty($this->gradeserror[$item->id][$userid])) {
                    $studentshtml .= $this->gradeserror[$item->id][$userid];
                }

                $studentshtml .=  '</td>' . "\n";
            }
            $studentshtml .= '</tr>';
        }
        return $studentshtml;
    }

    /**
     * Builds and return the HTML row of column totals.
     * @param  bool $grouponly Whether to return only group averages or all averages.
     * @return string HTML
     */
    function get_avghtml($grouponly=false) {
        global $CFG, $USER;

        $averagesdisplaytype   = $this->get_pref('averagesdisplaytype');
        $averagesdecimalpoints = $this->get_pref('averagesdecimalpoints');
        $meanselection = $this->get_pref('meanselection');
        $avghtml = '';

        if ($grouponly) {
            $straverage = get_string('groupavg', 'grades');
            $showaverages = $this->currentgroup && $this->get_pref('showgroups');
            $groupsql = $this->groupsql;
            $groupwheresql = $this->groupwheresql;
        } else {
            $straverage = get_string('average', 'grades');
            $showaverages = $this->get_pref('showaverages');
            $groupsql = null;
            $groupwheresql = null;
        }

        if ($meanselection == GRADE_AGGREGATE_MEAN_GRADED) {
            // non empty grades
            $meanstr = "AND NOT g.finalgrade IS NULL";
        } else {
            $meanstr = "";
        }
        if ($showaverages) {

            /** SQL for finding the SUM grades of all visible users ($CFG->gradebookroles) or group sum*/
            // do not sum -1 (no grade), treat as 0 for now
            $SQL = "SELECT g.itemid, SUM(g.finalgrade) as sum, COUNT(DISTINCT(u.id)) as count
                FROM {$CFG->prefix}grade_items gi LEFT JOIN
                     {$CFG->prefix}grade_grades g ON gi.id = g.itemid RIGHT OUTER JOIN
                     {$CFG->prefix}user u ON u.id = g.userid LEFT JOIN
                     {$CFG->prefix}role_assignments ra ON u.id = ra.userid
                     $groupsql
                WHERE gi.courseid = $this->courseid
                     $groupwheresql
                AND ra.roleid in ($this->gradebookroles)
                AND ra.contextid ".get_related_contexts_string($this->context)."
                $meanstr
                GROUP BY g.itemid";

            $sum_array = array();
            $count_array = array();
            $sums = get_records_sql($SQL);

            foreach ($sums as $itemid => $csum) {
                $sum_array[$itemid] = $csum->sum;
                $count_array[$itemid] = $csum->count;
            }

            $avghtml = '<tr><th>'.$straverage.'</th>';
            foreach ($this->items as $item) {
                $decimalpoints = $this->get_pref('decimalpoints', $item->id);
                // Determine which display type to use for this average
                $gradedisplaytype = $this->get_pref('gradedisplaytype', $item->id);
                if ($USER->gradeediting[$this->courseid]) {
                    $displaytype = GRADE_REPORT_GRADE_DISPLAY_TYPE_REAL;
                } elseif ($averagesdisplaytype == GRADE_REPORT_PREFERENCE_INHERIT) { // Inherit specific column or general preference
                    $displaytype = $gradedisplaytype;
                } else { // General preference overrides specific column display type
                    $displaytype = $averagesdisplaytype;
                }

                if ($averagesdecimalpoints != GRADE_REPORT_PREFERENCE_INHERIT) {
                    $decimalpoints = $averagesdecimalpoints;
                }

                if (empty($count_array[$item->id]) || !isset($sum_array[$item->id])) {
                    $avghtml .= '<td>-</td>';
                } else {
                    $sum = $sum_array[$item->id];

                    if ($item->scaleid) {
                        if ($grouponly) {
                            $finalsum = $sum_array[$item->id];
                            $finalavg = $finalsum/$count_array[$item->id];
                        } else {
                            $finalavg = $sum/$count_array[$item->id];
                        }

                        $scaleval = round($this->get_grade_clean($finalavg, $decimalpoints));
                        $scale_object = new grade_scale(array('id' => $item->scaleid), false);
                        $gradehtml = $scale_object->get_nearest_item($scaleval);
                        $rawvalue = $scaleval;
                    } else {
                        $gradeval = $this->get_grade_clean($sum/$count_array[$item->id], $decimalpoints);

                        $gradehtml = round($gradeval, $decimalpoints);
                        $rawvalue = $gradeval;
                    }

                    if ($displaytype == GRADE_REPORT_GRADE_DISPLAY_TYPE_PERCENTAGE) {
                        $gradeval = grade_grade::standardise_score($rawvalue, $item->grademin, $item->grademax, 0, 100);
                        $gradehtml = round($gradeval, $decimalpoints) . '%';
                    } elseif ($displaytype == GRADE_REPORT_GRADE_DISPLAY_TYPE_LETTER) {
                        $letters = grade_report::get_grade_letters();
                        $gradehtml = grade_grade::get_letter($letters, $gradeval, $item->grademin, $item->grademax);
                    }

                    $avghtml .= '<td>'.$gradehtml.'</td>';
                }
            }
            $avghtml .= '</tr>';
        }
        return $avghtml;
    }

    /**
     * Builds and return the HTML row of ranges for each column (i.e. range).
     * @return string HTML
     */
    function get_rangehtml() {
        global $USER;

        $scalehtml = '';
        if ($this->get_pref('showranges')) {
            $rangesdisplaytype = $this->get_pref('rangesdisplaytype');
            $rangesdecimalpoints = $this->get_pref('rangesdecimalpoints');
            $scalehtml = '<tr><th class="range">'.$this->get_lang_string('range','grades').'</th>';

            foreach ($this->items as $item) {
                $decimalpoints = $this->get_pref('decimalpoints', $item->id);
                // Determine which display type to use for this range
                $gradedisplaytype = $this->get_pref('gradedisplaytype', $item->id);

                if ($USER->gradeediting[$this->courseid]) {
                    $displaytype = GRADE_REPORT_GRADE_DISPLAY_TYPE_REAL;
                } elseif ($rangesdisplaytype == GRADE_REPORT_PREFERENCE_INHERIT) { // Inherit specific column or general preference
                    $displaytype = $gradedisplaytype;
                } else { // General preference overrides specific column display type
                    $displaytype = $rangesdisplaytype;
                }

                if ($rangesdecimalpoints != GRADE_REPORT_PREFERENCE_INHERIT) {
                    $decimalpoints = $rangesdecimalpoints;
                }

                if ($displaytype == GRADE_REPORT_GRADE_DISPLAY_TYPE_REAL) {
                    $grademin = $this->get_grade_clean($item->grademin, $decimalpoints);
                    $grademax = $this->get_grade_clean($item->grademax, $decimalpoints);
                } elseif ($displaytype == GRADE_REPORT_GRADE_DISPLAY_TYPE_PERCENTAGE) {
                    $grademin = 0;
                    $grademax = 100;
                } elseif ($displaytype == GRADE_REPORT_GRADE_DISPLAY_TYPE_LETTER) {
                    $letters = grade_report::get_grade_letters();
                    $grademin = end($letters);
                    $grademax = reset($letters);
                }

                $scalehtml .= '<th class="range">'. $grademin.'-'. $grademax.'</th>';
            }
            $scalehtml .= '</tr>';
        }
        return $scalehtml;
    }

    /**
     * Given a grade_category, grade_item or grade_grade, this function
     * figures out the state of the object and builds then returns a div
     * with the icons needed for the grader report.
     *
     * @param object $object
     * @return string HTML
     */
    function get_icons($element) {
        global $CFG, $USER;

        if (!$USER->gradeediting[$this->courseid]) {
            return '<div class="grade_icons" />';
        }

        // Init all icons
        $edit_icon             = $this->gtree->get_edit_icon($element, $this->gpr);
        $edit_calculation_icon = '';
        $show_hide_icon        = '';
        $contract_expand_icon  = '';
        $lock_unlock_icon      = '';

        if ($this->get_pref('showcalculations')) {
            $edit_calculation_icon = $this->gtree->get_calculation_icon($element, $this->gpr);
        }

        if ($this->get_pref('showeyecons')) {
           $show_hide_icon = $this->gtree->get_hiding_icon($element, $this->gpr);
        }

        if ($this->get_pref('showlocks')) {
            $lock_unlock_icon = $this->gtree->get_locking_icon($element, $this->gpr);
        }

        // If object is a category, display expand/contract icon
        if ($element['type'] == 'category' && $this->get_pref('aggregationview', $element['object']->id) == GRADE_REPORT_AGGREGATION_VIEW_COMPACT) {
            // Load language strings
            $strswitch_minus = $this->get_lang_string('contract', 'grades');
            $strswitch_plus  = $this->get_lang_string('expand', 'grades');
            $expand_contract = 'switch_minus'; // Default: expanded

            $state = get_user_preferences('grade_report_categorystate' . $element['object']->id, GRADE_CATEGORY_EXPANDED);

            if ($state == GRADE_CATEGORY_CONTRACTED) {
                $expand_contract = 'switch_plus';
            }
            $contract_expand_icon = '<a href="index.php?target=' . $element['eid']
                              . "&amp;action=$expand_contract" . $this->gtree->commonvars . "\">\n"
                              . '<img src="'.$CFG->pixpath.'/t/'.$expand_contract.'.gif" class="iconsmall" alt="'
                              . ${'str' . $expand_contract}.'" title="'.${'str' . $expand_contract}.'" /></a>'. "\n";
        }

        return '<div class="grade_icons">'.$edit_icon.$edit_calculation_icon.$show_hide_icon.$lock_unlock_icon.$contract_expand_icon.'</div>';
    }

    /**
     * Processes a single action against a category, grade_item or grade.
     * @param string $target eid ({type}{id}, e.g. c4 for category4)
     * @param string $action Which action to take (edit, delete etc...)
     * @return
     */
    function process_action($target, $action) {
        $targettype = substr($target, 0, 1);
        $targetid = substr($target, 1);
        switch ($action) {
            case 'switch_minus':
                set_user_preference('grade_report_categorystate' . $targetid, GRADE_CATEGORY_CONTRACTED);
                break;
            case 'switch_plus':
                set_user_preference('grade_report_categorystate' . $targetid, GRADE_CATEGORY_EXPANDED);
                break;
            default:
                break;
        }

        return true;
    }
}
?>