MDL-58227 mod_feedback: Delete duplicated completions records

This commit also fixes the way the previous completion record was
fetched to avoid the creation of new duplicates.

mod/feedback/classes/completion.php

@@ -517,7 +517,7 @@ class mod_feedback_completion extends mod_feedback_structure {
      */
     protected function find_last_completed() {
         global $USER, $DB;
-        if (isloggedin() || isguestuser()) {
+        if (!isloggedin() || isguestuser()) {
             // Not possible to retrieve completed feedback for guests.
             return false;
         }

mod/feedback/db/upgrade.php

@@ -149,5 +149,31 @@ function xmldb_feedback_upgrade($oldversion) {
     // Automatically generated Moodle v3.2.0 release upgrade line.
     // Put any upgrade step following this.
 
+    if ($oldversion < 2016120501) {
+
+        // Delete duplicated records in feedback_completed. We just keep the last record of completion.
+        // Related values in feedback_value won't be deleted (they won't be used and can be kept there as a backup).
+        $sql = "SELECT MAX(id) as maxid, userid, feedback, courseid
+                  FROM {feedback_completed}
+                 WHERE userid <> 0
+              GROUP BY userid, feedback, courseid
+                HAVING COUNT(id) > 1";
+
+        if ($duplicatedrows = $DB->get_recordset_sql($sql)) {
+            foreach ($duplicatedrows as $row) {
+                $DB->delete_records_select('feedback_completed', 'userid = ? AND feedback = ? AND courseid = ? AND id <> ?', array(
+                    $row->userid,
+                    $row->feedback,
+                    $row->courseid,
+                    $row->maxid,
+                ));
+            }
+        }
+        $duplicatedrows->close();
+
+        // Feedback savepoint reached.
+        upgrade_mod_savepoint(true, 2016120501, 'feedback');
+    }
+
     return true;
 }

mod/feedback/version.php

@@ -24,7 +24,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2016120500;       // The current module version (Date: YYYYMMDDXX)
+$plugin->version   = 2016120501;       // The current module version (Date: YYYYMMDDXX)
 $plugin->requires  = 2016112900;    // Requires this Moodle version
 $plugin->component = 'mod_feedback';   // Full name of the plugin (used for diagnostics)
 $plugin->cron      = 0;