Fix #196 Thanks to @antonio-c-mariani for this code.

classes/page_with_filter_controls.php

@@ -154,6 +154,7 @@ class mod_attendance_page_with_filter_controls {
                 $this->enddate = time();
                 break;
             case ATT_VIEW_ALL:
+            case ATT_VIEW_NOTPRESENT:
                 $this->startdate = 0;
                 $this->enddate = 0;
                 break;

classes/structure.php

@@ -96,6 +96,10 @@ class mod_attendance_structure {
     /** @var array of sessionid. */
     private $sessioninfo = array();
 
+    /** @var float number [0..1], the threshold for student to be shown at low grade report */
+    private $lowgradethreshold;
+
+
     /**
      * Initializes the attendance API instance using the data from DB
      *
@@ -1271,4 +1275,24 @@ class mod_attendance_structure {
         }
         return;
     }
+
+    /**
+     * Gets the lowgrade threshold to use.
+     *
+     */
+    public function get_lowgrade_threshold() {
+        if (!isset($this->lowgradethreshold)) {
+            $this->lowgradethreshold = 1;
+
+            if ($this->grade > 0) {
+                $gradeitem = grade_item::fetch(array('courseid' => $this->course->id, 'itemtype' => 'mod',
+                    'itemmodule' => 'attendance', 'iteminstance' => $this->id));
+                if ($gradeitem->gradepass > 0 && $gradeitem->grademax != $gradeitem->grademin) {
+                    $this->lowgradethreshold = ($gradeitem->gradepass - $gradeitem->grademin) / ($gradeitem->grademax - $gradeitem->grademin);
+                }
+            }
+        }
+
+        return $this->lowgradethreshold;
+    }
 }

lang/en/attendance.php

@@ -247,7 +247,7 @@ $string['invalidsessionendtime'] = 'The end time must be greater than start time
 $string['invalidstatus'] = 'You have selected an invalid status, please try again';
 $string['iptimemissing'] = 'Invalid minutes to release';
 $string['jumpto'] = 'Jump to';
-$string['lowgrade'] = 'Low grade';
+$string['below'] = 'Below {$a}%';
 $string['maxpossible'] = 'Maximum possible';
 $string['maxpossible_help'] = 'Shows the score each user can reach if they receive the maximum points in each session not yet taken (past and future):
     <ul>

renderables.php

@@ -548,11 +548,6 @@ class attendance_report_data implements renderable {
      * @param mod_attendance_structure $att
      */
     public function  __construct(mod_attendance_structure $att) {
-        $currenttime = time();
-        if ($att->pageparams->view == ATT_VIEW_NOTPRESENT) {
-            $att->pageparams->enddate = $currenttime;
-        }
-
         $this->pageparams = $att->pageparams;
 
         $this->users = $att->get_users($att->pageparams->group, $att->pageparams->page);
@@ -582,8 +577,9 @@ class attendance_report_data implements renderable {
         foreach ($this->users as $key => $user) {
             $usersummary = $this->summary->get_taken_sessions_summary_for($user->id);
             if ($att->pageparams->view != ATT_VIEW_NOTPRESENT ||
-                    $usersummary->takensessionspoints < $usersummary->takensessionsmaxpoints ||
-                    $usersummary->takensessionsmaxpoints == 0) {
+                attendance_calc_fraction($usersummary->takensessionspoints, $usersummary->takensessionsmaxpoints) <
+                $att->get_lowgrade_threshold()) {
+
                 $this->usersgroups[$user->id] = groups_get_all_groups($att->course->id, $user->id);
 
                 $this->sessionslog[$user->id] = $att->get_user_filtered_sessions_log($user->id);

renderer.php

@@ -206,7 +206,8 @@ class mod_attendance_renderer extends plugin_renderer_base {
         $views[ATT_VIEW_WEEKS] = get_string('weeks', 'attendance');
         $views[ATT_VIEW_DAYS] = get_string('days', 'attendance');
         if ($fcontrols->reportcontrol  && $fcontrols->att->grade > 0) {
-            $views[ATT_VIEW_NOTPRESENT] = get_string('lowgrade', 'attendance');
+            $a = $fcontrols->att->get_lowgrade_threshold() * 100;
+            $views[ATT_VIEW_NOTPRESENT] = get_string('below', 'attendance', $a);
         }
         if ($fcontrols->reportcontrol) {
             $views[ATT_VIEW_SUMMARY] = get_string('summary', 'attendance');

tests/behat/attendance_mod.feature

@@ -78,7 +78,7 @@ Feature: Teachers and Students can record session attendance
     And I click on "Get these logs" "button"
     Then "Attendance taken by student" "link" should exist
 
-  Scenario: Teachers can view low grade report and send a message
+  Scenario: Teachers can view below % report and send a message
     Given I log in as "teacher1"
     And I am on "Course 1" course homepage
     And I follow "Attendance"
@@ -88,7 +88,7 @@ Feature: Teachers and Students can record session attendance
       | id_sestime_endhour   | 02 |
     And I click on "id_submitbutton" "button"
     And I follow "Report"
-    And I follow "Low grade"
+    And I follow "Below"
     And I set the field "cb_selector" to "1"
     And I click on "Send a message" "button"
     And I should see "Message body"