/*
 * Copyright 2013 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.handler.codec.memcache.binary;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.CombinedChannelDuplexHandler;
import io.netty.handler.codec.PrematureChannelClosureException;
import io.netty.handler.codec.memcache.LastMemcacheContent;
import io.netty.util.internal.UnstableApi;

import java.util.List;
import java.util.concurrent.atomic.AtomicLong;

The client codec that combines the proper encoder and decoder.
 Use this codec if you want to implement a memcache client that speaks the binary protocol. It combines both the BinaryMemcacheResponseDecoder and the BinaryMemcacheRequestEncoder. 

Optionally, it counts the number of outstanding responses and raises an exception if - on connection
close - the list is not 0 (this is turned off by default). You can also define a chunk size for the
content, which defaults to 8192. This chunk size is the maximum, so if smaller chunks arrive they
will be passed up the pipeline and not queued up to the chunk size.
/**
 * The client codec that combines the proper encoder and decoder.
 * <p/>
 * Use this codec if you want to implement a memcache client that speaks the binary protocol. It
 * combines both the {@link BinaryMemcacheResponseDecoder} and the {@link BinaryMemcacheRequestEncoder}.
 * <p/>
 * Optionally, it counts the number of outstanding responses and raises an exception if - on connection
 * close - the list is not 0 (this is turned off by default). You can also define a chunk size for the
 * content, which defaults to 8192. This chunk size is the maximum, so if smaller chunks arrive they
 * will be passed up the pipeline and not queued up to the chunk size.
 */
@UnstableApi
public final class BinaryMemcacheClientCodec extends
        CombinedChannelDuplexHandler<BinaryMemcacheResponseDecoder, BinaryMemcacheRequestEncoder> {

    private final boolean failOnMissingResponse;
    private final AtomicLong requestResponseCounter = new AtomicLong();

    
Create a new BinaryMemcacheClientCodec with the default settings applied. /**
     * Create a new {@link BinaryMemcacheClientCodec} with the default settings applied.
     */
    public BinaryMemcacheClientCodec() {
        this(AbstractBinaryMemcacheDecoder.DEFAULT_MAX_CHUNK_SIZE);
    }

    
Create a new BinaryMemcacheClientCodec and set a custom chunk size. 
Params:
decodeChunkSize – the maximum chunk size./**
     * Create a new {@link BinaryMemcacheClientCodec} and set a custom chunk size.
     *
     * @param decodeChunkSize the maximum chunk size.
     */
    public BinaryMemcacheClientCodec(int decodeChunkSize) {
        this(decodeChunkSize, false);
    }

    
Create a new BinaryMemcacheClientCodec with custom settings. 
Params:
decodeChunkSize –       the maximum chunk size.
failOnMissingResponse – report if after close there are outstanding requests./**
     * Create a new {@link BinaryMemcacheClientCodec} with custom settings.
     *
     * @param decodeChunkSize       the maximum chunk size.
     * @param failOnMissingResponse report if after close there are outstanding requests.
     */
    public BinaryMemcacheClientCodec(int decodeChunkSize, boolean failOnMissingResponse) {
        this.failOnMissingResponse = failOnMissingResponse;
        init(new Decoder(decodeChunkSize), new Encoder());
    }

    private final class Encoder extends BinaryMemcacheRequestEncoder {

        @Override
        protected void encode(ChannelHandlerContext ctx, Object msg, List<Object> out) throws Exception {
            super.encode(ctx, msg, out);

            if (failOnMissingResponse && msg instanceof LastMemcacheContent) {
                requestResponseCounter.incrementAndGet();
            }
        }
    }

    private final class Decoder extends BinaryMemcacheResponseDecoder {

        Decoder(int chunkSize) {
            super(chunkSize);
        }

        @Override
        protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
            int oldSize = out.size();
            super.decode(ctx, in, out);

            if (failOnMissingResponse) {
                final int size = out.size();
                for (int i = oldSize; i < size; i ++) {
                    Object msg = out.get(i);
                    if (msg instanceof LastMemcacheContent) {
                        requestResponseCounter.decrementAndGet();
                    }
                }
            }
        }

        @Override
        public void channelInactive(ChannelHandlerContext ctx) throws Exception {
            super.channelInactive(ctx);

            if (failOnMissingResponse) {
                long missingResponses = requestResponseCounter.get();
                if (missingResponses > 0) {
                    ctx.fireExceptionCaught(new PrematureChannelClosureException(
                        "channel gone inactive with " + missingResponses +
                            " missing response(s)"));
                }
            }
        }
    }
}