/*
 * 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.logging.log4j.core.appender;

import org.apache.logging.log4j.core.AbstractLifeCycle;
import org.apache.logging.log4j.core.Appender;
import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.net.AbstractSocketManager;
import org.apache.logging.log4j.core.net.Advertiser;
import org.apache.logging.log4j.core.net.DatagramSocketManager;
import org.apache.logging.log4j.core.net.Protocol;
import org.apache.logging.log4j.core.net.SocketOptions;
import org.apache.logging.log4j.core.net.SslSocketManager;
import org.apache.logging.log4j.core.net.TcpSocketManager;
import org.apache.logging.log4j.core.net.ssl.SslConfiguration;
import org.apache.logging.log4j.plugins.Plugin;
import org.apache.logging.log4j.plugins.PluginAliases;
import org.apache.logging.log4j.plugins.PluginBuilderAttribute;
import org.apache.logging.log4j.plugins.PluginElement;
import org.apache.logging.log4j.plugins.PluginFactory;
import org.apache.logging.log4j.plugins.validation.constraints.ValidHost;
import org.apache.logging.log4j.plugins.validation.constraints.ValidPort;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

/**
 * An Appender that delivers events over socket connections. Supports both TCP and UDP.
 */
@Plugin(name = "Socket", category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = true)
public class SocketAppender extends AbstractOutputStreamAppender<AbstractSocketManager> {

    /**
     * Subclasses can extend this abstract Builder.
     * <h1>Defaults</h1>
     * <ul>
     * <li>host: "localhost"</li>
     * <li>protocol: "TCP"</li>
     * </ul>
     * <h1>Changes</h1>
     * <ul>
     * <li>Removed deprecated "delayMillis", use "reconnectionDelayMillis".</li>
     * <li>Removed deprecated "reconnectionDelay", use "reconnectionDelayMillis".</li>
     * </ul>
     * 
     * @param <B>
     *            The type to build.
     */
    public static abstract class AbstractBuilder<B extends AbstractBuilder<B>> extends AbstractOutputStreamAppender.Builder<B> {

        @PluginBuilderAttribute
        private boolean advertise;

        @PluginBuilderAttribute
        private int connectTimeoutMillis;

        @PluginBuilderAttribute
        @ValidHost
        private String host = "localhost";

        @PluginBuilderAttribute
        private boolean immediateFail = true;

        @PluginBuilderAttribute
        @ValidPort
        private int port;

        @PluginBuilderAttribute
        private Protocol protocol = Protocol.TCP;

        @PluginBuilderAttribute
        @PluginAliases({ "reconnectDelay", "reconnectionDelay", "delayMillis", "reconnectionDelayMillis" })
        private int reconnectDelayMillis;
        
        @PluginElement("SocketOptions")
        private SocketOptions socketOptions;
        
        @PluginElement("SslConfiguration")
        @PluginAliases({ "SslConfig" })
        private SslConfiguration sslConfiguration;

        public boolean getAdvertise() {
            return advertise;
        }

        public int getConnectTimeoutMillis() {
            return connectTimeoutMillis;
        }

        public String getHost() {
            return host;
        }

        public int getPort() {
            return port;
        }

        public Protocol getProtocol() {
            return protocol;
        }

        public SslConfiguration getSslConfiguration() {
            return sslConfiguration;
        }

        public boolean getImmediateFail() {
            return immediateFail;
        }

        public B setAdvertise(final boolean advertise) {
            this.advertise = advertise;
            return asBuilder();
        }

        public B setConnectTimeoutMillis(final int connectTimeoutMillis) {
            this.connectTimeoutMillis = connectTimeoutMillis;
            return asBuilder();
        }

        public B setHost(final String host) {
            this.host = host;
            return asBuilder();
        }

        public B setImmediateFail(final boolean immediateFail) {
            this.immediateFail = immediateFail;
            return asBuilder();
        }

        public B setPort(final int port) {
            this.port = port;
            return asBuilder();
        }

        public B setProtocol(final Protocol protocol) {
            this.protocol = protocol;
            return asBuilder();
        }

        public B setReconnectDelayMillis(final int reconnectDelayMillis) {
            this.reconnectDelayMillis = reconnectDelayMillis;
            return asBuilder();
        }

        public B setSocketOptions(final SocketOptions socketOptions) {
            this.socketOptions = socketOptions;
            return asBuilder();
        }

        public B setSslConfiguration(final SslConfiguration sslConfiguration) {
            this.sslConfiguration = sslConfiguration;
            return asBuilder();
        }

        public int getReconnectDelayMillis() {
            return reconnectDelayMillis;
        }

        public SocketOptions getSocketOptions() {
            return socketOptions;
        }

    }
    
    /**
     * Builds a SocketAppender.
     * <ul> 
     * <li>Removed deprecated "delayMillis", use "reconnectionDelayMillis".</li>
     * <li>Removed deprecated "reconnectionDelay", use "reconnectionDelayMillis".</li>
     * </ul> 
     */
    public static class Builder extends AbstractBuilder<Builder>
            implements org.apache.logging.log4j.plugins.util.Builder<SocketAppender> {

        @SuppressWarnings("resource")
        @Override
        public SocketAppender build() {
            boolean immediateFlush = isImmediateFlush();
            final boolean bufferedIo = isBufferedIo();
            final Layout<? extends Serializable> layout = getLayout();
            if (layout == null) {
                AbstractLifeCycle.LOGGER.error("No layout provided for SocketAppender");
                return null;
            }

            final String name = getName();
            if (name == null) {
                AbstractLifeCycle.LOGGER.error("No name provided for SocketAppender");
                return null;
            }

            final Protocol protocol = getProtocol();
            final Protocol actualProtocol = protocol != null ? protocol : Protocol.TCP;
            if (actualProtocol == Protocol.UDP) {
                immediateFlush = true;
            }

            final AbstractSocketManager manager = SocketAppender.createSocketManager(name, actualProtocol, getHost(), getPort(),
                    getConnectTimeoutMillis(), getSslConfiguration(), getReconnectDelayMillis(), getImmediateFail(), layout, getBufferSize(), getSocketOptions());

            return new SocketAppender(name, layout, getFilter(), manager, isIgnoreExceptions(),
                    !bufferedIo || immediateFlush, getAdvertise() ? getConfiguration().getAdvertiser() : null);
        }
    }
    
    @PluginFactory
    public static Builder newBuilder() {
        return new Builder();
    }

    private final Object advertisement;
    private final Advertiser advertiser;

    protected SocketAppender(final String name, final Layout<? extends Serializable> layout, final Filter filter,
            final AbstractSocketManager manager, final boolean ignoreExceptions, final boolean immediateFlush,
            final Advertiser advertiser) {
        super(name, layout, filter, ignoreExceptions, immediateFlush, null, manager);
        if (advertiser != null) {
            final Map<String, String> configuration = new HashMap<>(layout.getContentFormat());
            configuration.putAll(manager.getContentFormat());
            configuration.put("contentType", layout.getContentType());
            configuration.put("name", name);
            this.advertisement = advertiser.advertise(configuration);
        } else {
            this.advertisement = null;
        }
        this.advertiser = advertiser;
    }

    @Override
    public boolean stop(final long timeout, final TimeUnit timeUnit) {
        setStopping();
        super.stop(timeout, timeUnit, false);
        if (this.advertiser != null) {
            this.advertiser.unadvertise(this.advertisement);
        }
        setStopped();
        return true;
    }

    /**
     * Creates an AbstractSocketManager for TCP, UDP, and SSL.
     *
     * @throws IllegalArgumentException
     *             if the protocol cannot be handled.
     */
    protected static AbstractSocketManager createSocketManager(final String name, Protocol protocol, final String host,
            final int port, final int connectTimeoutMillis, final SslConfiguration sslConfig,
            final int reconnectDelayMillis, final boolean immediateFail, final Layout<? extends Serializable> layout,
            final int bufferSize, final SocketOptions socketOptions) {
        if (protocol == Protocol.TCP && sslConfig != null) {
            // Upgrade TCP to SSL if an SSL config is specified.
            protocol = Protocol.SSL;
        }
        if (protocol != Protocol.SSL && sslConfig != null) {
            LOGGER.info("Appender {} ignoring SSL configuration for {} protocol", name, protocol);
        }
        switch (protocol) {
        case TCP:
            return TcpSocketManager.getSocketManager(host, port, connectTimeoutMillis, reconnectDelayMillis,
                    immediateFail, layout, bufferSize, socketOptions);
        case UDP:
            return DatagramSocketManager.getSocketManager(host, port, layout, bufferSize);
        case SSL:
            return SslSocketManager.getSocketManager(sslConfig, host, port, connectTimeoutMillis, reconnectDelayMillis,
                    immediateFail, layout, bufferSize, socketOptions);
        default:
            throw new IllegalArgumentException(protocol.toString());
        }
    }

    @Override
    protected void directEncodeEvent(final LogEvent event) {
        // Disable garbage-free logging for now:
        // problem with UDP: 8K buffer size means that largish messages get broken up into chunks
        writeByteArrayToManager(event); // revert to classic (non-garbage free) logging
    }
}