package tv.pluto.grpc.utils;

import com.google.protobuf.AbstractMessage.Builder;
import com.google.protobuf.Message;
import com.google.protobuf.MessageOrBuilder;
import com.google.protobuf.util.JsonFormat;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;

/** Generic ProtoJsonUtil to be used to serialize and deserialize Proto to json */
public final class ProtoJsonUtil {

  /**
   * Makes a Json from a given message or builder
   *
   * @param messageOrBuilder is the instance
   * @return The string representation
   * @throws IOException if any error occurs
   */
  public static String toJson(MessageOrBuilder messageOrBuilder) throws IOException {
    return JsonFormat.printer().print(messageOrBuilder);
  }

  /**
   * Makes a new instance of message based on the json and the class
   *
   * @param <T> is the class type
   * @param json is the json instance
   * @param clazz is the class instance
   * @return An instance of T based on the json values
   * @throws IOException if any error occurs
   */
  @SuppressWarnings({"unchecked", "rawtypes"})
  public static <T extends Message> T fromJson(String json, Class<T> clazz) throws IOException {
    Builder builder;
    try {
      // Since we are dealing with a Message type, we can call newBuilder()
      builder = (Builder) clazz.getMethod("newBuilder").invoke(null);

    } catch (IllegalAccessException
        | IllegalArgumentException
        | InvocationTargetException
        | NoSuchMethodException
        | SecurityException e) {
      return null;
    }

    // The instance is placed into the builder values
    JsonFormat.parser().ignoringUnknownFields().merge(json, builder);

    // the instance will be from the build
    return (T) builder.build();
  }
}