Fix validation logic and make code more readable

cmd/web/handlers.go

@@ -68,11 +68,19 @@ func isRequestValid(r *createElectionRequestWithValidator) bool {
 	r.CheckField(validator.After(r.ExpiresAt, time.Now()), "expiresAt", "must expire in a future date")
 	r.CheckField(validator.GreaterThan(len(r.Choices), 1), "choices", "there must be more than 1 choice")
 
+	if r.AreVotersKnown {
 		r.CheckField(
-		!(r.AreVotersKnown && r.MaxVoters < 1),
+			validator.GreaterThan(r.MaxVoters, 0),
 			"maxVoters",
 			"must be greater than 0 when voters are known",
 		)
+	} else {
+		r.CheckField(
+			validator.GreaterThanOrEquals(r.MaxVoters, 0),
+			"maxVoters",
+			"must be a positive number",
+		)
+	}
 
 	return r.Valid()
 }

internal/validator/validator.go

@@ -60,6 +60,10 @@ func GreaterThan(value int, n int) bool {
 	return value > n
 }
 
+func GreaterThanOrEquals(value int, n int) bool {
+	return value >= n
+}
+
 func After(value time.Time, n time.Time) bool {
 	return value.After(n)
 }