MDL-71163 core: support relative dates in activity dates

AMOS BEGIN
 CPY [relativedatessubmissionduedateafter,mod_assign],[relativedatessubmissionduedateafter,core_course]
 CPY [relativedatessubmissionduedatebefore,mod_assign],[relativedatessubmissionduedatebefore,core_course]
AMOS END

course/classes/output/activity_information.php

@@ -80,12 +80,35 @@ class activity_information implements renderable, templatable {
 
         $data->cmid = $this->cminfo->id;
         $data->activityname = $this->cminfo->name;
-        $data->activitydates = $this->activitydates;
+        $this->build_dates_data($data);
         $data->hasdates = !empty($this->activitydates);
 
         return $data;
     }
 
+    /**
+     * Builds the dates data for export.
+     *
+     * @param stdClass $data
+     */
+    protected function build_dates_data(stdClass $data): void {
+        foreach ($this->activitydates as $date) {
+            if (empty($date['relativeto'])) {
+                $date['datestring'] = userdate($date['timestamp'], get_string('strftimedatetime', 'core_langconfig'));
+            } else {
+                $diffstr = get_time_interval_string($date['timestamp'], $date['relativeto']);
+                if ($date['timestamp'] >= $date['relativeto']) {
+                    $date['datestring'] = get_string('relativedatessubmissionduedateafter', 'core_course',
+                        ['datediffstr' => $diffstr]);
+                } else {
+                    $date['datestring'] = get_string('relativedatessubmissionduedatebefore', 'core_course',
+                        ['datediffstr' => $diffstr]);
+                }
+            }
+            $data->activitydates[] = $date;
+        }
+    }
+
     /**
      * Builds the completion data for export.
      *

course/templates/activity_date.mustache

@@ -22,9 +22,9 @@
     Example context (json):
     {
         "label": "Opens:",
-        "timestamp": 1293876000
+        "datestring": "6 April 2021, 6:46 PM"
     }
 }}
 <div>
-    <strong>{{label}}</strong> {{#userdate}} {{timestamp}}, {{#str}} strftimedatetime, core_langconfig {{/str}} {{/userdate}}
+    <strong>{{label}}</strong> {{datestring}}
 </div>

lang/en/course.php

@@ -97,6 +97,8 @@ $string['privacy:metadata:completionsummary'] = 'The course contains completion
 $string['privacy:metadata:favouritessummary'] = 'The course contains information relating to the course being starred by the user.';
 $string['recommend'] = 'Recommend';
 $string['recommendcheckbox'] = 'Recommend activity: {$a}';
+$string['relativedatessubmissionduedateafter'] = '{$a->datediffstr} after course start';
+$string['relativedatessubmissionduedatebefore'] = '{$a->datediffstr} before course start';
 $string['searchactivitiesbyname'] = 'Search for activities by name';
 $string['searchresults'] = 'Search results: {$a}';
 $string['submitsearch'] = 'Submit search';

mod/assign/classes/dates.php

@@ -42,6 +42,14 @@ class dates extends activity_dates {
      * @return array
      */
     protected function get_dates(): array {
+        global $CFG;
+
+        require_once($CFG->dirroot . '/mod/assign/locallib.php');
+
+        $course = get_course($this->cm->course);
+        $context = \context_module::instance($this->cm->id);
+        $assign = new \assign($context, $this->cm, $course);
+
         $timeopen = $this->cm->customdata['allowsubmissionsfromdate'] ?? null;
         $timedue = $this->cm->customdata['duedate'] ?? null;
         $now = time();
@@ -49,17 +57,25 @@ class dates extends activity_dates {
 
         if ($timeopen) {
             $openlabelid = $timeopen > $now ? 'activitydate:submissionsopen' : 'activitydate:submissionsopened';
-            $dates[] = [
+            $date = [
                 'label' => get_string($openlabelid, 'mod_assign'),
                 'timestamp' => (int) $timeopen,
             ];
+            if ($course->relativedatesmode && $assign->can_view_grades()) {
+                $date['relativeto'] = $course->startdate;
+            }
+            $dates[] = $date;
         }
 
         if ($timedue) {
-            $dates[] = [
+            $date = [
                 'label' => get_string('activitydate:submissionsdue', 'mod_assign'),
                 'timestamp' => (int) $timedue,
             ];
+            if ($course->relativedatesmode && $assign->can_view_grades()) {
+                $date['relativeto'] = $course->startdate;
+            }
+            $dates[] = $date;
         }
 
         return $dates;

mod/assign/lang/en/assign.php

@@ -450,8 +450,6 @@ $string['quickgradingresult'] = 'Quick grading';
 $string['quickgradingchangessaved'] = 'The grade changes were saved';
 $string['quickgrading_help'] = 'Quick grading allows you to assign grades (and outcomes) directly in the submissions table. Quick grading is not compatible with advanced grading and is not recommended when there are multiple markers.';
 $string['relativedatessubmissiontimeleft'] = 'Calculated for each student';
-$string['relativedatessubmissionduedateafter'] = '{$a->datediffstr} after course start';
-$string['relativedatessubmissionduedatebefore'] = '{$a->datediffstr} before course start';
 $string['removeallgroupoverrides'] = 'Delete all group overrides';
 $string['removealluseroverrides'] = 'Delete all user overrides';
 $string['reopenuntilpassincompatiblewithblindmarking'] = 'Reopen until pass option is incompatible with anonymous submissions, because the grades are not released to the gradebook until the student identities are revealed.';
@@ -640,3 +638,7 @@ $string['nolatesubmissions'] = 'No late submissions accepted. ';
 $string['nosubmissionsacceptedafter'] = 'No submissions accepted after ';
 $string['notsubmittedyet'] = 'Not submitted yet';
 $string['submissionsnotgraded'] = 'Submissions not graded: {$a}';
+
+// Deprecated since Moodle 3.11.
+$string['relativedatessubmissionduedateafter'] = '{$a->datediffstr} after course start';
+$string['relativedatessubmissionduedatebefore'] = '{$a->datediffstr} before course start';

mod/assign/lang/en/deprecated.txt

@@ -3,4 +3,6 @@ mysubmission,mod_assign
 nolatesubmissions,mod_assign
 nosubmissionsacceptedafter,mod_assign
 notsubmittedyet,mod_assign
+relativedatessubmissionduedateafter,mod_assign
+relativedatessubmissionduedatebefore,mod_assign
 submissionsnotgraded,mod_assign

mod/assign/lib.php

@@ -572,6 +572,16 @@ function mod_assign_cm_info_dynamic(cm_info $cm) {
         }
     }
 
+    // Calculate relative dates. The assignment module calculates relative date only for duedate.
+    // A user or group override always has higher priority over any relative date calculation.
+    if (empty($override->duedate) && !empty($cm->customdata['duedate'])) {
+        $course = get_course($cm->course);
+        $usercoursedates = course_get_course_dates_for_user_id($course, $USER->id);
+        if ($usercoursedates['start']) {
+            $override->duedate = $cm->customdata['duedate'] + $usercoursedates['startoffset'];
+        }
+    }
+
     // Populate some other values that can be used in calendar or on dashboard.
     if (!is_null($override->allowsubmissionsfromdate)) {
         $cm->override_customdata('allowsubmissionsfromdate', $override->allowsubmissionsfromdate);

mod/assign/renderer.php

@@ -342,10 +342,10 @@ class mod_assign_renderer extends plugin_renderer_base {
                 // Returns a formatted string, in the format '10d 10h 45m'.
                 $diffstr = get_time_interval_string($duedate, $summary->coursestartdate);
                 if ($duedate >= $summary->coursestartdate) {
-                    $cell2content = get_string('relativedatessubmissionduedateafter', 'mod_assign',
+                    $cell2content = get_string('relativedatessubmissionduedateafter', 'core_course',
                         ['datediffstr' => $diffstr]);
                 } else {
-                    $cell2content = get_string('relativedatessubmissionduedatebefore', 'mod_assign',
+                    $cell2content = get_string('relativedatessubmissionduedatebefore', 'core_course',
                         ['datediffstr' => $diffstr]);
                 }
             } else {

mod/assign/tests/behat/relative_dates.feature

@@ -35,6 +35,29 @@ I should be able to create an assignment with a due date relative to the course
     And I follow "Test assignment name"
     And I should not see "Assignment is overdue by:" in the "Time remaining" "table_row"
 
+  Scenario: As a student the due date I see for submitting my assignment is relative to my course start date
+    Given the following config values are set as admin:
+      | enablecourserelativedates | 1 |
+    And the following "courses" exist:
+    # A course with start date set to 1 Jan 2021.
+      | fullname | shortname  | category  | groupmode | relativedatesmode | startdate   |
+      | Course 1 | C1         | 0         | 1         | 1                 | 1609459200  |
+    And the following "users" exist:
+      | username | firstname  | lastname  | email                 |
+      | student1 | Student    | 1         | student1@example.com  |
+    And the following "course enrolments" exist:
+    # User's enrolment starts from 5 Jan 2021.
+      | user      | course  | role    | timestart   |
+      | student1  | C1      | student | 1609804800  |
+    And the following "activities" exist:
+    # The assignment's due date is 3 Jan 2021.
+      | activity  | name                  | intro                       | course  | idnumber  | assignsubmission_onlinetext_enabled | duedate     |
+      | assign    | Test assignment name  | Test assignment description | C1      | assign0   | 1                                   | 1609632000  |
+    When I log in as "student1"
+    And I am on "Course 1" course homepage
+    And I follow "Test assignment name"
+    Then the activity date in "Test assignment name" should contain "Due: 7 January 2021, 8:00 AM"
+
   Scenario: As a teacher, I should see the relative dates when reviewing assignment submissions
     Given the following config values are set as admin:
       | enablecourserelativedates | 1 |