MDL-60129 mod_book: added reset tags functionality

mod/book/lib.php

@@ -164,10 +164,44 @@ function book_print_recent_activity($course, $viewfullnames, $timestart) {
  * @return array status array
  */
 function book_reset_userdata($data) {
+    global $DB;
     // Any changes to the list of dates that needs to be rolled should be same during course restore and course reset.
     // See MDL-9367.
 
-    return array();
+    $status = [];
+
+    if (!empty($data->reset_book_tags)) {
+        // Loop through the books and remove the tags from the chapters.
+        if ($books = $DB->get_records('book', array('course' => $data->courseid))) {
+            foreach ($books as $book) {
+                if (!$cm = get_coursemodule_from_instance('book', $book->id)) {
+                    continue;
+                }
+
+                $context = context_module::instance($cm->id);
+                core_tag_tag::delete_instances('mod_book', null, $context->id);
+            }
+        }
+
+
+        $status[] = [
+            'component' => get_string('modulenameplural', 'book'),
+            'item' => get_string('tagsdeleted', 'book'),
+            'error' => false
+        ];
+    }
+
+    return $status;
+}
+
+/**
+ * The elements to add the course reset form.
+ *
+ * @param moodleform $mform
+ */
+function book_reset_course_form_definition(&$mform) {
+    $mform->addElement('header', 'bookheader', get_string('modulenameplural', 'book'));
+    $mform->addElement('checkbox', 'reset_book_tags', get_string('removeallbooktags', 'book'));
 }
 
 /**