Return all valid sections on bad request

src/main/java/nouritsu/types/Section.java

@@ -10,12 +10,20 @@ public enum Section {
   PASTA,
   RICE,
   MEAT,
+  FISH,
   DAIRY,
-  HYGIENE;
+  HYGIENE,
+  BEVERAGES;
 
   public static Either<String, Section> tryParse(String catName) {
     return Stream.of(Section.values())
       .find(c -> c.name().equalsIgnoreCase(catName))
       .toEither("Category “%s” not found".formatted(catName));
   }
+
+  public static String valuesAsString() {
+    return Stream.of(Section.values())
+      .map(Section::name)
+      .mkString("\nValid values are: ", ", ", "");
+  }
 }

src/main/java/nouritsu/types/ShoppingItem.java

@@ -4,6 +4,8 @@ import io.vavr.control.Either;
 
 public record ShoppingItem(String name, Section section) {
   public static Either<Resp, ShoppingItem> tryParse(String name, String category) {
-    return Section.tryParse(category).map(c -> new ShoppingItem(name, c));
+    return Section.tryParse(category)
+      .map(c -> new ShoppingItem(name, c))
+      .mapLeft(msg -> Resp.BAD_REQUEST.apply(msg + Section.valuesAsString()));
   }
 }

src/main/java/nouritsu/types/Store.java

@@ -10,7 +10,7 @@ import io.vavr.control.Either;
 public record Store(String name, Seq<Section>sections) {
   public static Either<Resp, Store> tryParse(String name, String sections) {
     return Either.traverse(List.of(sections.split(",")), Section::tryParse)
-      .mapLeft(errors -> Resp.BAD_REQUEST.apply(errors.mkString("\n")))
+      .mapLeft(errors -> Resp.BAD_REQUEST.apply(errors.mkString("\n") + Section.valuesAsString()))
       .map(secs -> new Store(name, secs));
   }
 }