Extract relativeTime string parsing for readability

This makes it easier to read that we properly escape the `+` and the
overall Regex is easier to verify.

Author: vmcj

webapp/src/Validator/Constraints/TimeStringValidator.php

@@ -10,6 +10,7 @@ class TimeStringValidator extends ConstraintValidator
 {
     public function validate(mixed $value, Constraint $constraint): void
     {
+        $relativeRegex = "\d+:\d\d(:\d\d(\.\d{1,6})?)?";
         if (!$constraint instanceof TimeString) {
             throw new UnexpectedTypeException($constraint, TimeString::class);
         }
@@ -24,8 +25,8 @@ public function validate(mixed $value, Constraint $constraint): void
 
         if ($constraint->allowRelative) {
             $regex   = $constraint->relativeIsPositive ?
-                "/^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{1,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}|\+\d+:\d\d(:\d\d(\.\d{1,6})?)?)$/" :
-                "/^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{1,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}|-\d+:\d\d(:\d\d(\.\d{1,6})?)?)$/";
+                "/^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{2,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}|\+" . $relativeRegex . ")$/" :
+                "/^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{1,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}|-"  . $relativeRegex . ")$/";
             $message = $constraint->absoluteRelativeMessage;
         } else {
             $regex   = "/^\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{1,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}$/";