package com.ilmlf.clientconnection;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.PrettyPrinter;
import com.fasterxml.jackson.core.util.DefaultIndenter;
import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
import com.fasterxml.jackson.core.util.Separators;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

import java.io.UncheckedIOException;

public final class Snapshot {
  private static final ObjectMapper objectMapper = buildObjectMapper();
  private static final PrettyPrinter pp = buildDefaultPrettyPrinter();

  /**
   * Workaround for an incompatibility between latest Jackson and json-snapshot libs.
   * <p>
   * Intended to replace {@code io.github.jsonSnapshot.SnapshotMatcher#defaultJsonFunction}
   *
   * @see <a href="https://github.com/json-snapshot/json-snapshot.github.io/issues/27">Issue in json-snapshot project</a>
   */
  public static String asJsonString(Object object) {
    try {
      return objectMapper.writer(pp).writeValueAsString(object);
    } catch (JsonProcessingException e) {
      throw new UncheckedIOException(e);
    }
  }

  /**
   * Unmodified copy of {@code io.github.jsonSnapshot.SnapshotMatcher#buildObjectMapper}
   */
  private static ObjectMapper buildObjectMapper() {
    ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.configure(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS, true);
    objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

    objectMapper.setVisibility(
        objectMapper
            .getSerializationConfig()
            .getDefaultVisibilityChecker()
            .withFieldVisibility(JsonAutoDetect.Visibility.ANY)
            .withGetterVisibility(JsonAutoDetect.Visibility.NONE)
            .withSetterVisibility(JsonAutoDetect.Visibility.NONE)
            .withCreatorVisibility(JsonAutoDetect.Visibility.NONE));
    return objectMapper;
  }

  /**
   * Modified copy of {@code io.github.jsonSnapshot.SnapshotMatcher#buildDefaultPrettyPrinter}
   */
  private static PrettyPrinter buildDefaultPrettyPrinter() {
    DefaultPrettyPrinter pp =
        new DefaultPrettyPrinter("") {
          @Override
          public DefaultPrettyPrinter createInstance() {
            return this;
          }

          @Override
          public DefaultPrettyPrinter withSeparators(Separators separators) {
            this._separators = separators;
            this._objectFieldValueSeparatorWithSpaces =
                separators.getObjectFieldValueSeparator() + " ";
            return this;
          }
        };
    DefaultPrettyPrinter.Indenter lfOnlyIndenter = new DefaultIndenter("  ", "\n");
    pp.indentArraysWith(lfOnlyIndenter);
    pp.indentObjectsWith(lfOnlyIndenter);
    return pp;
  }
}