package org.warp.jcwdb;

import java.io.ByteArrayOutputStream;

import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.io.Output;

import net.openhft.hashing.LongHashFunction;

public class DBGenericObjectParser extends DBTypeParserImpl<Object> implements DBTypedObjectParser<Object> {
	private static final LongHashFunction hashFunction = net.openhft.hashing.LongHashFunction.xx();
	private static final Kryo kryo = new Kryo();
	static {
		kryo.setRegistrationRequired(false);
	}
	
	private static final DBReader<Object> defaultReader = (i, size) -> {
		return kryo.readClassAndObject(i);
	};
	
	public DBReader<Object> getReader() {
		return defaultReader;
	}
	
	public DBDataOutput<Object> getWriter(final Object value) {
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		Output tmpO = new Output(baos);
		kryo.writeClassAndObject(tmpO, value);
		tmpO.flush();
		final byte[] bytes = baos.toByteArray();
		final long hash = hashFunction.hashBytes(bytes);
		tmpO.close();
		return DBDataOutput.create((o) -> {
			o.write(bytes);
		}, DBStandardTypes.GENERIC_OBJECT, bytes.length, hash);
	}

	@Override
	public long calculateHash(Object value) {
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		Output tmpO = new Output(baos);
		kryo.writeClassAndObject(tmpO, value);
		tmpO.flush();
		final byte[] bytes = baos.toByteArray();
		final long hash = hashFunction.hashBytes(bytes);
		tmpO.close();
		return hash;
	}


	@Override
	public <U> void registerClass(Class<U> clazz, int id) {
		if (id >= Integer.MAX_VALUE - 100) {
			throw new IndexOutOfBoundsException();
		}
		kryo.register(clazz, id + 100);
	}
}