 <?php
 
 /**
  * File in which the grade_report_stats class is defined.
  */
  
require_once($CFG->dirroot . '/grade/report/lib.php');
require_once($CFG->libdir.'/tablelib.php');
require_once($CFG->dirroot . '/grade/report/stats/statistics/load.php');

/**
 * Class providing the API for the stats report, including harvesters,
 * reports, and adaptor methods for turing grades in to statistics.
 * @uses grade_report
 * @package gradebook
 */
class grade_report_stats extends grade_report {
    /**
     * Capability to view hidden items.
     * TODO: Add a check for hidden items and grades.
     * @var boolean $canviewhidden
     */
    private $canviewhidden;
    
    /**
     * Categories to be displayed based on report setting.
     * @var array $collapsed
     */
    private $collapsed;
    
    /**
     * Grade objects of users in the course
     * @var array $grades
     */
    private $grades;
    
    /**
     * Array of users final grades affter filtered based on
     * settings.
     * @var array $finalgrades
     */
    private $finalgrades;
    
    /**
     * The value returned from each statistic.
     * @var array $reportedstats
     */
    private $reportedstats;
    
    /**
     * The html of the report to output.
     * @var string $html
     */     
    public $html;
    
    /**
     * The table class used to make the html of the report.
     * @var object $table
     */     
     private $table;

    /**
     * Constructor. Initialises grade_tree, sets up group, baseurl
     * and pbarurl.
     * @param int $courseid the coures id for the report
     * @param object $gpr grade plugin tracking object
     * @context string $context
     */
    public function __construct($courseid, $gpr, $context) {
        global $CFG;
        parent::__construct($courseid, $gpr, $context, null);

        $this->canviewhidden = has_capability('moodle/grade:viewhidden', get_context_instance(CONTEXT_COURSE, $this->course->id));
        
        /// Set categories to be displayed.
        if($this->get_pref('stats', 'aggregationview') == GRADE_REPORT_PREFERENCE_DEFAULT || $this->get_pref('stats', 'aggregationview') == GRADE_REPORT_AGGREGATION_VIEW_FULL) {
            $this->collapsed = array('aggregatesonly' => array(), 'gradesonly' => array());
        } elseif($this->get_pref('stats', 'aggregationview') == GRADE_REPORT_AGGREGATION_VIEW_AGGREGATES_ONLY) {
            $this->collapsed = array('aggregatesonly' => array());
        } elseif($this->get_pref('stats', 'aggregationview') == GRADE_REPORT_AGGREGATION_VIEW_GRADES_ONLY) {
            $this->collapsed = array('gradesonly' => array());
        } else {
            $this->collapsed = array('aggregatesonly' => array(), 'gradesonly' => array());
        }
    
        /// Set up urls
        $this->baseurl = 'index.php?id=' . $this->courseid;
        $this->pbarurl = 'index.php?id=' . $this->courseid;

        /// Set the position of the aggregation categorie based on pref
        $switch = $this->get_pref('stats', 'aggregationposition');
        if ($switch == '' && isset($CFG->grade_aggregationposition)) {
            $switch = grade_get_setting($this->courseid, 'aggregationposition', $CFG->grade_aggregationposition);
        }
    
        /// Build grade tree
        $this->gtree = new grade_tree($this->courseid, false, $switch);

        /// Set up Groups
        if ($this->get_pref('stats', 'showgroups') || is_null($this->get_pref('stats', 'showgroups'))) {
            if(is_callable(array($this, 'setup_groups'))) {
                $this->setup_groups();
            } else {
                $this->local_setup_groups();
            }
        }
    }

    public function process_data($data){}
    public function process_action($target, $action){}

    private function local_setup_groups() {
        global $CFG;

        /// find out current groups mode
        $this->group_selector = groups_print_course_menu($this->course, $this->pbarurl, true);
        $this->currentgroup = groups_get_course_group($this->course);

        if ($this->currentgroup) {
            $this->groupsql = " LEFT JOIN {groups_members} gm ON gm.userid = u.id ";
            $this->groupwheresql = " AND gm.groupid = ? ";
            $this->groupwheresql_params = array($this->currentgroup);
        }
    }

    /**
     * Based on load user function from grader report.
     * Pulls out the userids of the users to be used in the stats.
     * @return array array of user ids to use in stats
     */
    public function load_users() {
        global $CFG, $DB;
        
        if(isset($DB) && !is_null($DB)) {
            $params = array();
            list($usql, $gbr_params) = $DB->get_in_or_equal(explode(',', $this->gradebookroles));
        
            $sql = "SELECT u.id
                    FROM {user} u
                        JOIN {role_assignments} ra ON u.id = ra.userid
                        $this->groupsql
                    WHERE ra.roleid $usql
                        $this->groupwheresql
                        AND ra.contextid ".get_related_contexts_string($this->context);
        
            $params = array_merge($gbr_params, $this->groupwheresql_params);
            $this->users = $DB->get_records_sql($sql, $params);
        } else {
            $sql = "SELECT u.id, u.firstname, u.lastname, u.imagealt, u.picture, u.idnumber
                      FROM {$CFG->prefix}user u
                           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);
        
            $this->users = get_records_sql($sql);
        }

        if (empty($this->users)) {
            $this->userselect = '';
            $this->users = array();
        } else {
            if(isset($DB) && !is_null($DB)) {
                list($usql, $params) = $DB->get_in_or_equal(array_keys($this->users));
                $this->userselect = "AND g.userid $usql";
                $this->userselect_params = $params;
            }else{
                $this->userselect = 'AND g.userid in ('.implode(',', array_keys($this->users)).')';
            }
        }
        
        return $this->users;
    }
    
    /**
     * Encode an array of stat's data in to a stirng so it can
     * be put in the get part of a url.
     * @param arrray $array array of data to encode
     * @param object $item grade_item to use to fromat stats
     * @param object $stat stats object to use to format stats
     * @return string encoded string
     */
    private function encode_array($array, $item, $stat) {
        $string = '';
    
        /// Encode each elment by puting a delimiter and base64 encoding it.
        foreach($array as $id=>$data) {
            $string .= addslashes(grade_format_gradevalue($data, $item, true, $stat->displaytype, $stat->decimals)) . '"'; 
        }
        return strtr(base64_encode($string), '+/=', '-_,');
    }

    /**
     * Harvest the grades from the data base and build the finalgrades array.
     * Filters out hidden, locked and null grades based on users settings.
     * Partly based on grader reports load_final_grades function.
     */
    public function harvest_data() {
        global $CFG, $DB;

        if(isset($DB) && !is_null($DB)) {
            $params = array_merge(array($this->courseid), $this->userselect_params);
            
            /// please note that we must fetch all grade_grades fields if we want to contruct grade_grade object from it!
            $sql = "SELECT g.*
                  FROM {grade_items} gi,
                       {grade_grades} g
                 WHERE g.itemid = gi.id AND gi.courseid = ? {$this->userselect}";
            
            $grades = $DB->get_records_sql($sql, $params);
        } else {
            /// please note that we must fetch all grade_grades fields if we want to contruct grade_grade object from it!
            $sql = "SELECT g.*
                  FROM {$CFG->prefix}grade_items gi,
                       {$CFG->prefix}grade_grades g
                 WHERE g.itemid = gi.id AND gi.courseid = {$this->courseid} {$this->userselect}";
            
            $grades = get_records_sql($sql);
        }
        
        $userids = array_keys($this->users);

        if ($grades) {
            foreach ($grades as $graderec) {
                if (in_array($graderec->userid, $userids) and array_key_exists($graderec->itemid, $this->gtree->items)) { // some items may not be present!!
                    $this->grades[$graderec->itemid][$graderec->userid] = new grade_grade($graderec, false);
                    $this->grades[$graderec->itemid][$graderec->userid]->grade_item =& $this->gtree->items[$graderec->itemid]; // db caching
                }
            }
        }

        /// prefil grades that do not exist yet
        foreach ($userids as $userid) {
            foreach ($this->gtree->items as $itemid=>$unused) {
                if (!isset($this->grades[$itemid][$userid])) {
                    $this->grades[$itemid][$userid] = new grade_grade();
                    $this->grades[$itemid][$userid]->itemid = $itemid;
                    $this->grades[$itemid][$userid]->userid = $userid;
                    $this->grades[$itemid][$userid]->grade_item =& $this->gtree->items[$itemid]; // db caching
                }
            }
        }

        $this->finalgrades = array();

        /// Build finalgrades array and filliter out unwanted grades.
        foreach ($this->gtree->items as $id=>$item) {
            if(($item->gradetype == GRADE_TYPE_SCALE &&  ($this->get_pref('stats', 'showscaleitems') || is_null($this->get_pref('stats', 'showscaleitems')))) 
                || ($item->gradetype == GRADE_TYPE_VALUE &&  ($this->get_pref('stats', 'showvalueitems') || is_null($this->get_pref('stats', 'showvalueitems'))))) {             
                    $this->finalgrades[$id] = array();
                    $i = 0;
                    
                    if(isset($this->grades[$id]) && !is_null($this->grades[$id])) {
                        foreach ($this->grades[$id] as $grade) {
                            if( (($grade->is_hidden() && ($this->get_pref('stats', 'usehidden') || is_null($this->get_pref('stats', 'usehidden')))) || !$grade->is_hidden())
                                && (($grade->is_locked() && ($this->get_pref('stats', 'uselocked') || is_null($this->get_pref('stats', 'uselocked')))) || !$grade->is_locked())) {
                                    if($this->get_pref('stats', 'incompleasmin') && is_null($grade->finalgrade)) {
                                        $this->finalgrades[$id][$i] = $item->grademin;
                                        $i++;
                                    } elseif(!is_null($grade->finalgrade)) {
                                        $this->finalgrades[$id][$i] = $grade->finalgrade;
                                        $i++;
                                    }
                            }               
                        }
                    }
                }
        }
    }

    /**
     * Runs grades for each item threw the report functions 
     * of each stats class in $stats and stores the values in
     * reportedstats.
     * TODO: Do not report on hidden items if the user can not see them.
     */
    public function report_data() {
        global $stats;
        $this->reportedstats = array();

        foreach($stats as $name=>$stat) {
            if($this->get_pref('stats', $name) || is_null($this->get_pref('stats', $name))) {
                $this->reportedstats[$name] = array();

                foreach($this->finalgrades as $itemid=>$item) {
                    sort($item);
                    if(count($item) > 0) {
                        $this->reportedstats[$name][$itemid] = $stat->report_data($item, $this->gtree->items[$itemid]);
                    } else {
                        $this->reportedstats[$name][$itemid] = null;
                    }
                }
            }
        }
    }

    /**
     * Take the reported data and adapt it in to HTML to output.
     * HTML is stored in html.
     * TODO: Deal with tables growing to wide.
     * TODO: Make it look nice.
     */
    public function adapt_data() {
        global $stats;
    
        /// Set up table arrays
        $tablecolumns = array('statistic');
        $tableheaders = array($this->get_lang_string('statistic', 'gradereport_stats'));
        
        /// Set up range column and number of grades column
        $ranges = array('<strong>' . $this->get_lang_string('range', 'gradereport_stats') . '</strong>');
        $numgrades = array('<strong>' . $this->get_lang_string('num_grades', 'gradereport_stats') . '</strong>');
    
        /// Loop threw items and build arrays
        foreach($this->finalgrades as $itemid=>$item) {
            array_push($tablecolumns, $itemid);
            array_push($tableheaders,  $this->gtree->items[$itemid]->get_name());
            array_push($ranges, '<strong>' . grade_format_gradevalue($this->gtree->items[$itemid]->grademin, $this->gtree->items[$itemid], true) . '-' . grade_format_gradevalue($this->gtree->items[$itemid]->grademax, $this->gtree->items[$itemid], true) . '<strong>' );
            array_push($numgrades, count($item));
        }
    
        /// Set up flexible table
        $this->table = new flexible_table('grade-report-stats-' . $this->courseid);
        $this->table->define_columns($tablecolumns);
        $this->table->define_headers($tableheaders);
        $this->table->define_baseurl($this->baseurl);
        $this->table->collapsible(true);
        $this->table->set_attribute('cellspacing', '1');
        $this->table->set_attribute('id', 'stats-grade');
        $this->table->set_attribute('class', 'grade-report-stats gradestable flexible');
        $this->table->setup();

        /// If ranges are being shown add them to the table
        if ($this->get_pref('stats', 'showranges')){
            $this->table->add_data($ranges);
            $this->table->add_separator();
        }

        /// Loop threw all the reported data and format it in to cells
        /// If stat retured an array of values display the elements or 
        /// make a link to a popup with the data in it.
        foreach($this->reportedstats as $name=>$data) {
            $row = array('<strong>' . $stats[$name]->name . '</strong>');

            foreach($data as $itemid=>$stat) {
                if(!is_array($stat)) {
                    array_push($row, grade_format_gradevalue($stat, $this->gtree->items[$itemid], true, $stats[$name]->displaytype, $stats[$name]->decimals));
                } else {
                    $statstring = "";
           
                    for($i = 0; $i < 2; $i++) {
                        if($i >= count($stat)) {
                            break;
                        }
                        $statstring .= grade_format_gradevalue($stat[$i], $this->gtree->items[$itemid], true, $stats[$name]->displaytype, $stats[$name]->decimals) . ', ';
                    }
               
                    if($i < count($stat)) {
                        $statstring = "<a href=\"#\" onClick=\"javascript:window.open('arrayview.php?data={$this->encode_array($stat, $this->gtree->items[$itemid], $stats[$name])}','{$this->get_lang_string('moredata', 'gradereport_stats')}','width=300,height=500,menubar=no,status=no,location=no,directories=no,toolbar=no,scrollbars=yes');\">". $statstring . '....</a>';  
                    } else {
                        $statstring = substr($statstring, 0, strlen($statstring) - 2);
                    }
                    array_push($row, $statstring);
                }
            }
            $this->table->add_data($row);
        }
    
        /// If the number of grades is being shown add it to the table.
        if ($this->get_pref('stats', 'shownumgrades')){
            $this->table->add_separator();
            $this->table->add_data($numgrades);
        }
    
        /// Build html
        ob_start();
            if($this->currentgroup == 0) {
                echo '<strong>Group:</strong> All participants';
            } else {
                echo '<strong>Group:</strong> ' . groups_get_group_name($this->currentgroup);
            }
            $this->table->print_html();
        $this->html = ob_get_clean();
    }

    /**
     * Builds HTML for toggles on top of report.
     * Based on grader report  get_toggles_html
     * @return string html code for toggles.
     */
    public function get_toggles_html() {
        global $CFG, $USER;

        $html = '<div id="stats-report-toggles" style="vertical-align: text-top; text-align: center;">';
        $html .= $this->print_toggle('numgrades', true);
        $html .= $this->print_toggle('groups', true);
        $html .= $this->print_toggle('ranges', true);
        $html .= '</div>';
        
        return $html;
    }
    
    /**
     * Builds HTML for each individual toggle.
     * Based on grader report print_toggle
     * @param string $type The toggle type.
     * @param bool $return Wheather ro return the HTML or print it.
     */
    private function print_toggle($type, $return=false) {
        global $CFG;

        $icons = array('eyecons' => 't/hide.gif',
                       'numgrades' => 't/grades.gif',
                       'calculations' => 't/calc.gif',
                       'locks' => 't/lock.gif',
                       'averages' => 't/mean.gif',
                       'nooutcomes' => 't/outcomes.gif');

        $pref_name = 'grade_report_statsshow' . $type;

        if (array_key_exists($pref_name, $CFG)) {
            $show_pref = get_user_preferences($pref_name, $CFG->$pref_name);
        } else {
            $show_pref = get_user_preferences($pref_name);
        }

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

        $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 {
            $image_name = "t/$type.gif";
        }

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

        $img = '<img src="'.$CFG->pixpath.'/'.$image_name.'" class="iconsmall" alt="'
                      .$string.'" title="'.$string.'" />'. "\n";

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

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