/**
 * Copyright 2016 Nikita Koksharov
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.redisson.codec;

import java.io.IOException;

import org.redisson.client.codec.Codec;
import org.redisson.client.handler.State;
import org.redisson.client.protocol.Decoder;
import org.redisson.client.protocol.Encoder;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import net.jpountz.lz4.LZ4Compressor;
import net.jpountz.lz4.LZ4Factory;
import net.jpountz.lz4.LZ4SafeDecompressor;

/**
 * LZ4 compression codec.
 * Uses inner <code>Codec</code> to convert object to binary stream.
 * <code>FstCodec</code> used by default.
 *
 * https://github.com/jpountz/lz4-java
 *
 * @see org.redisson.codec.FstCodec
 *
 * @author Nikita Koksharov
 *
 */
public class LZ4Codec implements Codec {

    private final LZ4Factory factory = LZ4Factory.fastestInstance();

    private final Codec innerCodec;

    public LZ4Codec() {
        this(new FstCodec());
    }

    public LZ4Codec(Codec innerCodec) {
        this.innerCodec = innerCodec;
    }

    private final Decoder<Object> decoder = new Decoder<Object>() {
        @Override
        public Object decode(ByteBuf buf, State state) throws IOException {
            byte[] bytes = new byte[buf.readableBytes()];
            buf.readBytes(bytes);

            LZ4SafeDecompressor decompressor = factory.safeDecompressor();
            bytes = decompressor.decompress(bytes, bytes.length*3);
            ByteBuf bf = Unpooled.wrappedBuffer(bytes);
            try {
                return innerCodec.getValueDecoder().decode(bf, state);
            } finally {
                bf.release();
            }
        }
    };

    private final Encoder encoder = new Encoder() {

        @Override
        public byte[] encode(Object in) throws IOException {
            LZ4Compressor compressor = factory.fastCompressor();
            byte[] bytes = innerCodec.getValueEncoder().encode(in);
            return compressor.compress(bytes);
        }
    };

    @Override
    public Decoder<Object> getMapValueDecoder() {
        return getValueDecoder();
    }

    @Override
    public Encoder getMapValueEncoder() {
        return getValueEncoder();
    }

    @Override
    public Decoder<Object> getMapKeyDecoder() {
        return getValueDecoder();
    }

    @Override
    public Encoder getMapKeyEncoder() {
        return getValueEncoder();
    }

    @Override
    public Decoder<Object> getValueDecoder() {
        return decoder;
    }

    @Override
    public Encoder getValueEncoder() {
        return encoder;
    }

}