/**
  * Renders the chart
  * @param IUser $logged_user
  * @return string
  */
 function render(IUser $logged_user)
 {
     $db_result = DB::execute("SELECT milestone_id, COUNT(*) as count FROM " . TABLE_PREFIX . "project_objects WHERE project_id = ? AND type='Task' AND state >= ? AND visibility >= ? GROUP BY milestone_id", $this->project->getId(), STATE_VISIBLE, $logged_user->getMinVisibility());
     $array_result = $db_result instanceof DBResult ? $db_result->toArrayIndexedBy('milestone_id') : false;
     if (is_foreachable($array_result)) {
         $pie_chart = new PieChart('400px', '400px', 'milestone_eta_report_pie_chart_placeholder');
         $this->serie_array = array();
         $this->milestones = array();
         // Set data for the rest
         foreach ($array_result as $serie_data) {
             $point = new ChartPoint('1', $serie_data['count']);
             $serie = new ChartSerie($point);
             if (intval($serie_data['milestone_id'])) {
                 $milestone = new RemediaMilestone(intval($serie_data['milestone_id']));
                 $label = PieChart::makeShortForPieChart($milestone->getName());
                 $this->milestones[] = $milestone;
             } else {
                 $label = lang('No Milestone');
             }
             //if
             $serie->setOption('label', $label);
             $this->serie_array[] = $serie;
         }
         //foreach
         $pie_chart->addSeries($this->serie_array);
         return $pie_chart->render();
     } else {
         return '<p class="empty_slate">' . lang('There are no milestones in this project.') . '</p>';
     }
     //if
 }