MDL-25982 Workshop: users from the same group may be excluded from allocation in visible group mode

If the Workshop is in the visible group mode, members of the same group
can be now optionally excluded from random allocation for a given user.

mod/workshop/allocation/random/lang/en/workshopallocation_random.php

@@ -32,6 +32,7 @@ $string['allocationsettings'] = 'Allocation settings';
 $string['assessmentdeleteddetail'] = 'Assessment deallocated: <strong>{$a->reviewername}</strong> is no longer reviewer of <strong>{$a->authorname}</strong>';
 $string['assesswosubmission'] = 'Participants can assess without having submitted anything';
 $string['confignumofreviews'] = 'Default number of submissions to be randomly allocated';
+$string['excludesamegroup'] = 'Prevent reviews by peers from the same group';
 $string['noallocationtoadd'] = 'No allocations to add';
 $string['nogroupusers'] = '<p>Warning: If the workshop is in \'visible groups\' mode or \'separate groups\' mode, then users MUST be part of at least one group to have peer-assessments allocated to them by this tool. Non-grouped users can still be given new self-assessments or have existing assessments removed.</p>
 <p>These users are currently not in a group: {$a}</p>';

mod/workshop/allocation/random/lib.php

@@ -76,6 +76,7 @@ class workshop_random_allocator implements workshop_allocator {
             $o                  = array();      // list of output messages
             $numofreviews       = required_param('numofreviews', PARAM_INT);
             $numper             = required_param('numper', PARAM_INT);
+            $excludesamegroup   = optional_param('excludesamegroup', false, PARAM_BOOL);
             $removecurrent      = optional_param('removecurrent', false, PARAM_BOOL);
             $assesswosubmission = optional_param('assesswosubmission', false, PARAM_BOOL);
             $addselfassessment  = optional_param('addselfassessment', false, PARAM_BOOL);
@@ -96,7 +97,11 @@ class workshop_random_allocator implements workshop_allocator {
                 } else {
                     $curassessments = $assessments;
                 }
-                $randomallocations  = $this->random_allocation($authors, $reviewers, $curassessments, $numofreviews, $numper, $o);
+                $options                     = array();
+                $options['numofreviews']     = $numofreviews;
+                $options['numper']           = $numper;
+                $options['excludesamegroup'] = $excludesamegroup;
+                $randomallocations  = $this->random_allocation($authors, $reviewers, $curassessments, $o, $options);
                 $newallocations     = array_merge($newallocations, $randomallocations);
                 $o[] = 'ok::' . get_string('numofrandomlyallocatedsubmissions', 'workshopallocation_random', count($randomallocations));
                 unset($randomallocations);
@@ -398,19 +403,27 @@ class workshop_random_allocator implements workshop_allocator {
      * is to connect each "circle" (circles are representing either authors or reviewers) with a required
      * number of "squares" (the other type than circles are).
      *
+     * The passed $options array must provide keys:
+     *      (int)numofreviews - number of reviews to be allocated to each circle
+     *      (int)numper - what user type the circles represent.
+     *      (bool)excludesamegroup - whether to prevent peer submissions from the same group in visible group mode
+     *
      * @param array    $authors      structure of grouped authors
      * @param resource $reviewers    structure of grouped reviewers
      * @param array    $assessments  currently assigned assessments to be kept
-     * @param mixed    $numofreviews number of reviews to be allocated to each circle
-     * @param mixed    $numper       what user type the circles represent
      * @param array    $o            reference to an array of log messages
+     * @param array    $options      allocation options
      * @return array                 array of (reviewerid => authorid) pairs
      */
-    protected function random_allocation($authors, $reviewers, $assessments, $numofreviews, $numper, &$o) {
+    protected function random_allocation($authors, $reviewers, $assessments, &$o, array $options) {
         if (empty($authors) || empty($reviewers)) {
             // nothing to be done
             return array();
         }
+
+        $numofreviews = $options['numofreviews'];
+        $numper       = $options['numper'];
+
         if (self::USERTYPE_AUTHOR == $numper) {
             // circles are authors, squares are reviewers
             $o[] = 'info::Trying to allocate ' . $numofreviews . ' review(s) per author'; // todo translate
@@ -514,6 +527,16 @@ class workshop_random_allocator implements workshop_allocator {
                         } elseif (VISIBLEGROUPS == $gmode) {
                             $trygroups = array_diff_key($squaregroupsworkload, array(0 => null));   // all but [0]
                             $trygroups = array_diff_key($trygroups, array_flip($failedgroups));     // without previous failures
+                            if ($options['excludesamegroup']) {
+                                // exclude groups the circle is member of
+                                $excludegroups = array();
+                                foreach (array_diff_key($allcircles, array(0 => null)) as $exgroupid => $exgroupmembers) {
+                                    if (array_key_exists($circleid, $exgroupmembers)) {
+                                        $excludegroups[$exgroupid] = null;
+                                    }
+                                }
+                                $trygroups = array_diff_key($trygroups, $excludegroups);
+                            }
                             $targetgroup = $this->get_element_with_lowest_workload($trygroups);
                         }
                         if ($targetgroup === false) {

mod/workshop/allocation/random/settings_form.php

@@ -74,6 +74,14 @@ class workshop_random_allocator_form extends moodleform {
         $mform->setDefault('numper', workshop_random_allocator::USERTYPE_AUTHOR);
         $mform->addGroup($grpnumofreviews, 'grpnumofreviews', get_string('numofreviews', 'workshopallocation_random'),
                 array(' '), false);
+
+        if (VISIBLEGROUPS == $gmode) {
+            $mform->addElement('checkbox', 'excludesamegroup', get_string('excludesamegroup', 'workshopallocation_random'));
+            $mform->setDefault('excludesamegroup', 0);
+        } else {
+            $mform->addElement('hidden', 'excludesamegroup', 0);
+        }
+
         $mform->addElement('checkbox', 'removecurrent', get_string('removecurrentallocations', 'workshopallocation_random'));
         $mform->setDefault('removecurrent', 0);