/*
 * Licensed to Crate under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.  Crate 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.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial
 * agreement.
 */

package io.crate.http.netty;

import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.inject.Singleton;
import org.elasticsearch.common.network.NetworkService;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.util.BigArrays;
import org.elasticsearch.http.netty3.Netty3HttpServerTransport;
import org.elasticsearch.threadpool.ThreadPool;
import org.jboss.netty.channel.*;

import java.util.concurrent.CopyOnWriteArrayList;
import java.util.function.Supplier;


@Singleton
public class CrateNettyHttpServerTransport extends Netty3HttpServerTransport {

    /**
     * A data structure for items that can be added to the channel pipeline of the HTTP transport.
     */
    public static class ChannelPipelineItem {

        final String base;
        final String name;
        final Supplier<ChannelUpstreamHandler> handlerFactory;

        /**
         * @param base              the name of the existing handler in the pipeline before/after which the new handler should be added
         * @param name              the name of the new handler that should be added to the pipeline
         * @param handlerFactory    a supplier that provides a new instance of the handler
         */
        public ChannelPipelineItem(String base, String name, Supplier<ChannelUpstreamHandler> handlerFactory) {
            this.base = base;
            this.name = name;
            this.handlerFactory = handlerFactory;
        }
    }

    private CopyOnWriteArrayList<ChannelPipelineItem> addBeforeList = new CopyOnWriteArrayList<>();
    private CopyOnWriteArrayList<ChannelPipelineItem> addAfterList = new CopyOnWriteArrayList<>();

    @Inject
    public CrateNettyHttpServerTransport(Settings settings,
                                         NetworkService networkService,
                                         BigArrays bigArrays,
                                         ThreadPool threadPool) {
        super(settings, networkService, bigArrays, threadPool);
    }

    @Override
    public ChannelPipelineFactory configureServerChannelPipelineFactory() {
        return new CrateHttpChannelPipelineFactory(this, detailedErrorsEnabled, threadPool);
    }

    public void addBefore(ChannelPipelineItem item) {
        addBeforeList.add(item);
    }

    public void addAfter(ChannelPipelineItem item) {
        addAfterList.add(item);
    }

    protected class CrateHttpChannelPipelineFactory extends HttpChannelPipelineFactory {

        CrateHttpChannelPipelineFactory(CrateNettyHttpServerTransport transport,
                                               boolean detailedErrorsEnabled,
                                               ThreadPool threadPool) {
            super(transport, detailedErrorsEnabled, threadPool.getThreadContext());
        }

        @Override
        public ChannelPipeline getPipeline() throws Exception {
            ChannelPipeline pipeline = super.getPipeline();
            for (ChannelPipelineItem item : addBeforeList) {
                pipeline.addBefore(item.base, item.name, item.handlerFactory.get());
            }
            for (ChannelPipelineItem item : addAfterList) {
                pipeline.addAfter(item.base, item.name, item.handlerFactory.get());
            }
            return pipeline;
        }
    }
}