package com.ankurm.jackson3.part0setup;

import tools.jackson.core.JsonParser;
import tools.jackson.core.JsonToken;
import tools.jackson.databind.JsonNode;
import tools.jackson.databind.json.JsonMapper;

/**
 * Post: Jackson 101 — https://ankurm.com/jackson-java-tutorial/
 * Section: "Jackson's Three Processing Models"
 *
 * The same payload read three ways, so the trade-off is concrete rather than a table.
 */
public class A03ThreeProcessingModels {

    public record Order(Long orderId, String status) { }

    private static final String JSON = "{\"orderId\":1001,\"status\":\"SHIPPED\"}";

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

        // 1. DATA BINDING — the right answer roughly 95% of the time.
        Order bound = mapper.readValue(JSON, Order.class);
        System.out.println("1. data binding : " + bound);

        // 2. TREE MODEL — schema not known at compile time; navigate a JsonNode.
        JsonNode tree = mapper.readTree(JSON);
        System.out.println("2. tree model   : orderId=" + tree.path("orderId").asInt()
                + " status=" + tree.path("status").asString());

        // 3. STREAMING — token by token, constant memory, no document ever built.
        StringBuilder streamed = new StringBuilder();
        try (JsonParser parser = mapper.createParser(JSON)) {
            while (parser.nextToken() != null) {
                if (parser.currentToken() == JsonToken.PROPERTY_NAME) {
                    String field = parser.currentName();
                    parser.nextToken();                       // advance to the value
                    streamed.append(field).append('=').append(parser.getString()).append(' ');
                }
            }
        }
        System.out.println("3. streaming    : " + streamed.toString().trim());
    }
}