TT#69063 - Fix stuck timeset event list

* Add validation for 'By week day number'
	   field because if set incorrectly, JS
	   would fail to parse it and the events
	   list would get stuck

Change-Id: Iac3ef0635e3728af9b900e68cc21ad0de60d0da9

lib/NGCP/Panel/Form/TimeSet/EventAdvanced.pm

@@ -691,6 +691,18 @@ sub custom_set_values {
     return $fif;
 }
 
+sub validate_byday {
+    my ($self, $field) = @_;
+
+    if (my $weekdaynumber = $field->field('weekdaynumber')) {
+        unless ($weekdaynumber->value =~ /^([+-]?\d)(MO|TU|WE|TH|FR|SA|SO)$/) {
+            $weekdaynumber->add_error($weekdaynumber->label . ' should be like (\+|-)?\d*(MO|TU|WE|TH|FR|SA|SO) (e.g. 5FR)');
+            return 0;
+        }
+    }
+    return 1;
+}
+
 1;
 
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