package com.ankurm.jackson3.part2modernjava;

import com.fasterxml.jackson.annotation.JsonInclude;
import tools.jackson.databind.json.JsonMapper;

import java.util.Optional;

/**
 * Post: Jackson with Records, Optionals, Sealed Classes
 *       https://ankurm.com/jackson-java-records-optionals/
 * Section: "Jackson with Optional<T>"
 *
 * Jackson 3 handles Optional natively. There is no jackson-datatype-jdk8
 * dependency in the pom and no registerModule(new Jdk8Module()) call — those are
 * Jackson 2 requirements, and the Jdk8Module class does not exist under
 * tools.jackson at all.
 */
public class C02OptionalFields {

    public record CustomerProfile(String customerName, Optional<String> middleName) { }

    /** NON_ABSENT is the inclusion value that understands Optional.empty(). */
    @JsonInclude(JsonInclude.Include.NON_ABSENT)
    public record CompactProfile(String customerName, Optional<String> middleName) { }

    public static void main(String[] args) {
        JsonMapper mapper = JsonMapper.builder().build();

        // Present value: the Optional is unwrapped, not wrapped in {"present":true}.
        System.out.println("present : "
                + mapper.writeValueAsString(new CustomerProfile("Alice", Optional.of("Marie"))));

        // Empty Optional: serialises as null by default.
        System.out.println("empty   : "
                + mapper.writeValueAsString(new CustomerProfile("Bob", Optional.empty())));

        // NON_ABSENT omits the property entirely instead of writing null.
        System.out.println("absent  : "
                + mapper.writeValueAsString(new CompactProfile("Bob", Optional.empty())));

        // Deserialise back.
        String json = "{\"customerName\":\"Alice\",\"middleName\":\"Marie\"}";
        CustomerProfile restored = mapper.readValue(json, CustomerProfile.class);
        System.out.println("isPresent: " + restored.middleName().isPresent());

        // A missing property deserialises to Optional.empty(), never to null.
        CustomerProfile missing = mapper.readValue("{\"customerName\":\"Carol\"}", CustomerProfile.class);
        System.out.println("missing -> " + missing.middleName() + " (null? "
                + (missing.middleName() == null) + ")");
    }
}