/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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 org.apache.dubbo.remoting.transport.netty4;

import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.logger.ErrorTypeAwareLogger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.remoting.ChannelHandler;
import org.apache.dubbo.remoting.Codec;
import org.apache.dubbo.remoting.Codec2;
import org.apache.dubbo.remoting.Constants;
import org.apache.dubbo.remoting.RemotingException;
import org.apache.dubbo.remoting.buffer.ChannelBuffer;
import org.apache.dubbo.remoting.exchange.Request;
import org.apache.dubbo.remoting.exchange.Response;
import org.apache.dubbo.remoting.transport.AbstractChannel;
import org.apache.dubbo.remoting.transport.codec.CodecAdapter;
import org.apache.dubbo.remoting.utils.PayloadDropper;
import org.apache.dubbo.rpc.model.FrameworkModel;

import java.net.InetSocketAddress;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicBoolean;

import io.netty.buffer.ByteBuf;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.handler.codec.EncoderException;
import io.netty.util.ReferenceCountUtil;

import static org.apache.dubbo.common.constants.CommonConstants.DEFAULT_ENCODE_IN_IO_THREAD;
import static org.apache.dubbo.common.constants.CommonConstants.DEFAULT_TIMEOUT;
import static org.apache.dubbo.common.constants.CommonConstants.ENCODE_IN_IO_THREAD_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.TIMEOUT_KEY;
import static org.apache.dubbo.common.constants.LoggerCodeConstants.TRANSPORT_FAILED_CLOSE;
import static org.apache.dubbo.rpc.model.ScopeModelUtil.getFrameworkModel;

/**
 * NettyChannel maintains the cache of channel.
 */
final class NettyChannel extends AbstractChannel {

    private static final ErrorTypeAwareLogger logger = LoggerFactory.getErrorTypeAwareLogger(NettyChannel.class);
    /**
     * the cache for netty channel and dubbo channel
     */
    private static final ConcurrentMap<Channel, NettyChannel> CHANNEL_MAP = new ConcurrentHashMap<>();
    /**
     * netty channel
     */
    private final Channel channel;

    private final Map<String, Object> attributes = new ConcurrentHashMap<>();

    private final AtomicBoolean active = new AtomicBoolean(false);

    private final Netty4BatchWriteQueue writeQueue;

    private Codec2 codec;

    private final boolean encodeInIOThread;

    /**
     * The constructor of NettyChannel.
     * It is private so NettyChannel usually create by {@link NettyChannel#getOrAddChannel(Channel, URL, ChannelHandler)}
     *
     * @param channel netty channel
     * @param url
     * @param handler dubbo handler that contain netty handler
     */
    private NettyChannel(Channel channel, URL url, ChannelHandler handler) {
        super(url, handler);
        if (channel == null) {
            throw new IllegalArgumentException("netty channel == null;");
        }
        this.channel = channel;
        this.writeQueue = Netty4BatchWriteQueue.createWriteQueue(channel);
        this.codec = getChannelCodec(url);
        this.encodeInIOThread = getUrl().getParameter(ENCODE_IN_IO_THREAD_KEY, DEFAULT_ENCODE_IN_IO_THREAD);
    }

    /**
     * Get dubbo channel by netty channel through channel cache.
     * Put netty channel into it if dubbo channel don't exist in the cache.
     *
     * @param ch      netty channel
     * @param url
     * @param handler dubbo handler that contain netty's handler
     * @return
     */
    static NettyChannel getOrAddChannel(Channel ch, URL url, ChannelHandler handler) {
        if (ch == null) {
            return null;
        }
        NettyChannel ret = CHANNEL_MAP.get(ch);
        if (ret == null) {
            NettyChannel nettyChannel = new NettyChannel(ch, url, handler);
            if (ch.isActive()) {
                nettyChannel.markActive(true);
                ret = CHANNEL_MAP.putIfAbsent(ch, nettyChannel);
            }
            if (ret == null) {
                ret = nettyChannel;
            }
        } else {
            ret.markActive(true);
        }
        return ret;
    }

    /**
     * Remove the inactive channel.
     *
     * @param ch netty channel
     */
    static void removeChannelIfDisconnected(Channel ch) {
        if (ch != null && !ch.isActive()) {
            NettyChannel nettyChannel = CHANNEL_MAP.remove(ch);
            if (nettyChannel != null) {
                nettyChannel.markActive(false);
            }
        }
    }

    static void removeChannel(Channel ch) {
        if (ch != null) {
            NettyChannel nettyChannel = CHANNEL_MAP.remove(ch);
            if (nettyChannel != null) {
                nettyChannel.markActive(false);
            }
        }
    }

    @Override
    public InetSocketAddress getLocalAddress() {
        return (InetSocketAddress) channel.localAddress();
    }

    @Override
    public InetSocketAddress getRemoteAddress() {
        return (InetSocketAddress) channel.remoteAddress();
    }

    @Override
    public boolean isConnected() {
        return !isClosed() && active.get();
    }

    public boolean isActive() {
        return active.get();
    }

    public void markActive(boolean isActive) {
        active.set(isActive);
    }

    /**
     * Send message by netty and whether to wait the completion of the send.
     *
     * @param message message that need send.
     * @param sent    whether to ack async-sent
     * @throws RemotingException throw RemotingException if wait until timeout or any exception thrown by method body that surrounded by try-catch.
     */
    @Override
    public void send(Object message, boolean sent) throws RemotingException {
        // whether the channel is closed
        super.send(message, sent);

        boolean success = true;
        int timeout = 0;
        ByteBuf buf = null;
        try {
            Object outputMessage = message;
            if (!encodeInIOThread) {
                buf = channel.alloc().buffer();
                ChannelBuffer buffer = new NettyBackedChannelBuffer(buf);
                codec.encode(this, buffer, message);
                outputMessage = buf;
            }
            ChannelFuture future = writeQueue.enqueue(outputMessage).addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    if (!(message instanceof Request)) {
                        return;
                    }
                    ChannelHandler handler = getChannelHandler();
                    if (future.isSuccess()) {
                        handler.sent(NettyChannel.this, message);
                    } else {
                        Throwable t = future.cause();
                        if (t == null) {
                            return;
                        }
                        Response response = buildErrorResponse((Request) message, t);
                        handler.received(NettyChannel.this, response);
                    }
                }
            });

            if (sent) {
                // wait timeout ms
                timeout = getUrl().getPositiveParameter(TIMEOUT_KEY, DEFAULT_TIMEOUT);
                success = future.await(timeout);
            }
            Throwable cause = future.cause();
            if (cause != null) {
                throw cause;
            }
        } catch (Throwable e) {
            removeChannelIfDisconnected(channel);
            if (buf != null) {
                // Release the ByteBuf if an exception occurs
                ReferenceCountUtil.safeRelease(buf);
            }
            throw new RemotingException(
                    this,
                    "Failed to send message " + PayloadDropper.getRequestWithoutData(message) + " to "
                            + getRemoteAddress() + ", cause: " + e.getMessage(),
                    e);
        }
        if (!success) {
            throw new RemotingException(
                    this,
                    "Failed to send message " + PayloadDropper.getRequestWithoutData(message) + " to "
                            + getRemoteAddress() + "in timeout(" + timeout + "ms) limit");
        }
    }

    @Override
    public void close() {
        try {
            super.close();
        } catch (Exception e) {
            logger.warn(TRANSPORT_FAILED_CLOSE, "", "", e.getMessage(), e);
        }
        try {
            removeChannelIfDisconnected(channel);
        } catch (Exception e) {
            logger.warn(TRANSPORT_FAILED_CLOSE, "", "", e.getMessage(), e);
        }
        try {
            attributes.clear();
        } catch (Exception e) {
            logger.warn(TRANSPORT_FAILED_CLOSE, "", "", e.getMessage(), e);
        }
        try {
            if (logger.isInfoEnabled()) {
                logger.info("Close netty channel " + channel);
            }
            channel.close();
        } catch (Exception e) {
            logger.warn(TRANSPORT_FAILED_CLOSE, "", "", e.getMessage(), e);
        }
    }

    @Override
    public boolean hasAttribute(String key) {
        return attributes.containsKey(key);
    }

    @Override
    public Object getAttribute(String key) {
        return attributes.get(key);
    }

    @Override
    public void setAttribute(String key, Object value) {
        // The null value is not allowed in the ConcurrentHashMap.
        if (value == null) {
            attributes.remove(key);
        } else {
            attributes.put(key, value);
        }
    }

    @Override
    public void removeAttribute(String key) {
        attributes.remove(key);
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((channel == null) ? 0 : channel.hashCode());
        return result;
    }

    @Override
    protected void setUrl(URL url) {
        super.setUrl(url);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }

        // FIXME: a hack to make org.apache.dubbo.remoting.exchange.support.DefaultFuture.closeChannel work
        if (obj instanceof NettyClient) {
            NettyClient client = (NettyClient) obj;
            return channel.equals(client.getNettyChannel());
        }

        if (getClass() != obj.getClass()) {
            return false;
        }
        NettyChannel other = (NettyChannel) obj;
        if (channel == null) {
            if (other.channel != null) {
                return false;
            }
        } else if (!channel.equals(other.channel)) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "NettyChannel [channel=" + channel + "]";
    }

    public Channel getNioChannel() {
        return channel;
    }

    /**
     * build a bad request's response
     *
     * @param request the request
     * @param t       the throwable. In most cases, serialization fails.
     * @return the response
     */
    private static Response buildErrorResponse(Request request, Throwable t) {
        Response response = new Response(request.getId(), request.getVersion());
        if (t instanceof EncoderException) {
            response.setStatus(Response.SERIALIZATION_ERROR);
        } else {
            response.setStatus(Response.BAD_REQUEST);
        }
        response.setErrorMessage(StringUtils.toString(t));
        return response;
    }

    private static Codec2 getChannelCodec(URL url) {
        String codecName = url.getParameter(Constants.CODEC_KEY);
        if (StringUtils.isEmpty(codecName)) {
            // codec extension name must stay the same with protocol name
            codecName = url.getProtocol();
        }
        FrameworkModel frameworkModel = getFrameworkModel(url.getScopeModel());
        if (frameworkModel.getExtensionLoader(Codec2.class).hasExtension(codecName)) {
            return frameworkModel.getExtensionLoader(Codec2.class).getExtension(codecName);
        } else if (frameworkModel.getExtensionLoader(Codec.class).hasExtension(codecName)) {
            return new CodecAdapter(
                    frameworkModel.getExtensionLoader(Codec.class).getExtension(codecName));
        } else {
            return frameworkModel.getExtensionLoader(Codec2.class).getExtension("default");
        }
    }

    public void setCodec(Codec2 codec) {
        this.codec = codec;
    }
}
