Allow also negative offsets

Author: vmcj

webapp/src/Controller/Jury/ContestController.php

@@ -956,15 +956,19 @@ private function checkTimezones(FormInterface $form): ?Response
         foreach (['Activate', 'Deactivate', 'Start', 'End', 'Freeze', 'Unfreeze'] as $timeString) {
             $tmpValue = $formData->{'get' . $timeString . 'timeString'}();
             if ($tmpValue !== '' && !is_null($tmpValue)) {
+                // Check if absolute time
                 if (preg_match("/\d{2}-\d{2}-\d{2}.*/", $tmpValue) === 1) {
                     $chr = $tmpValue[10]; // The separator between date & time
                     $fields = explode($chr, $tmpValue);
                     // First field is the time, 2nd/3th might be timezone or offset
                     $tmpValue = substr(str_replace($fields[0], '', $tmpValue), 1); // Also remove the separator
+                    // Case with a timezone
                     if (str_contains($tmpValue, ' ')) {
                         $fields = explode(' ', $tmpValue);
                     } elseif (str_contains($tmpValue, '+')) {
                         $fields = explode('+', $tmpValue);
+                    } elseif (str_contains($tmpValue, '-')) {
+                        $fields = explode('-', $tmpValue);
                     } elseif (substr($tmpValue, -1) === 'Z') {
                         $timeZones[] = 'UTC';
                         continue;