feat: UserCreateRequest model & validation

src/main/java/eu/ztsh/wymiana/validation/AdultValidator.java

@@ -0,0 +1,42 @@
+package eu.ztsh.wymiana.validation;
+
+import jakarta.validation.ConstraintValidator;
+import jakarta.validation.ConstraintValidatorContext;
+
+import java.time.LocalDate;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+import java.util.Arrays;
+import java.util.Objects;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+public class AdultValidator implements ConstraintValidator<Adult, String> {
+
+    private final Pattern pattern = Pattern.compile("\\d{11}");
+    private final DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyyMMdd");
+
+    @Override
+    public boolean isValid(String value, ConstraintValidatorContext context) {
+        if (!pattern.matcher(value).matches()) {
+            return false;
+        }
+        var datePart = Arrays.stream(value.substring(0, 6).split("")).map(Integer::parseInt).toArray(Integer[]::new);
+        final String prefix;
+        if (datePart[2] > 1) {
+            datePart[2] = (datePart[2] - 2);
+            prefix = "20";
+        } else {
+            prefix = "19";
+        }
+        var dateStamp = prefix.concat(Arrays.stream(datePart).map(Objects::toString).collect(Collectors.joining()));
+        try {
+            return LocalDate.parse(dateStamp, dtf)
+                .plusYears(18)
+                .isBefore(LocalDate.now(context.getClockProvider().getClock()));
+        } catch (DateTimeParseException exception) {
+            return false;
+        }
+    }
+
+}