/*
 * 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.net;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Serializable;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.UnknownHostException;

import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.appender.ManagerFactory;
import org.apache.logging.log4j.core.net.ssl.SslConfiguration;
import org.apache.logging.log4j.util.Strings;

/**
 *
 */
public class SslSocketManager extends TcpSocketManager {
    public static final int DEFAULT_PORT = 6514;
    private static final SslSocketManagerFactory FACTORY = new SslSocketManagerFactory();
    private final SslConfiguration sslConfig;

    /**
     *
     *
     * @param name          The unique name of this connection.
     * @param os            The OutputStream.
     * @param sock          The Socket.
     * @param inetAddress          The Internet address of the host.
     * @param host          The name of the host.
     * @param port          The port number on the host.
     * @param connectTimeoutMillis the connect timeout in milliseconds.
     * @param delay         Reconnection interval.
     * @param immediateFail
     * @param layout        The Layout.
     * @param bufferSize The buffer size.
     */
    public SslSocketManager(final String name, final OutputStream os, final Socket sock,
            final SslConfiguration sslConfig, final InetAddress inetAddress, final String host, final int port,
            final int connectTimeoutMillis, final int delay, final boolean immediateFail,
            final Layout<? extends Serializable> layout, final int bufferSize) {
        super(name, os, sock, inetAddress, host, port, connectTimeoutMillis, delay, immediateFail, layout, bufferSize);
        this.sslConfig = sslConfig;
    }

    private static class SslFactoryData {
        protected SslConfiguration sslConfiguration;
        private final String host;
        private final int port;
        private final int connectTimeoutMillis;
        private final int delayMillis;
        private final boolean immediateFail;
        private final Layout<? extends Serializable> layout;
        private final int bufferSize;

        public SslFactoryData(final SslConfiguration sslConfiguration, final String host, final int port,
                final int connectTimeoutMillis, final int delayMillis, final boolean immediateFail,
                final Layout<? extends Serializable> layout, final int bufferSize) {
            this.host = host;
            this.port = port;
            this.connectTimeoutMillis = connectTimeoutMillis;
            this.delayMillis = delayMillis;
            this.immediateFail = immediateFail;
            this.layout = layout;
            this.sslConfiguration = sslConfiguration;
            this.bufferSize = bufferSize;
        }
    }

    public static SslSocketManager getSocketManager(final SslConfiguration sslConfig, final String host, int port,
            final int connectTimeoutMillis, int reconnectDelayMillis, final boolean immediateFail,
            final Layout<? extends Serializable> layout, final int bufferSize) {
        if (Strings.isEmpty(host)) {
            throw new IllegalArgumentException("A host name is required");
        }
        if (port <= 0) {
            port = DEFAULT_PORT;
        }
        if (reconnectDelayMillis == 0) {
            reconnectDelayMillis = DEFAULT_RECONNECTION_DELAY_MILLIS;
        }
        return (SslSocketManager) getManager("TLS:" + host + ':' + port, new SslFactoryData(sslConfig, host, port,
                connectTimeoutMillis, reconnectDelayMillis, immediateFail, layout, bufferSize), FACTORY);
    }

    @Override
    protected Socket createSocket(final String host, final int port) throws IOException {
        final SSLSocketFactory socketFactory = createSslSocketFactory(sslConfig);
        final InetSocketAddress address = new InetSocketAddress(host, port);
        final Socket newSocket = socketFactory.createSocket();
        newSocket.connect(address, getConnectTimeoutMillis());
        return newSocket;
    }

    private static SSLSocketFactory createSslSocketFactory(final SslConfiguration sslConf) {
        SSLSocketFactory socketFactory;

        if (sslConf != null) {
            socketFactory = sslConf.getSslSocketFactory();
        } else {
            socketFactory = (SSLSocketFactory) SSLSocketFactory.getDefault();
        }

        return socketFactory;
    }


    private static class SslSocketManagerFactory implements ManagerFactory<SslSocketManager, SslFactoryData> {

        private static class TlsSocketManagerFactoryException extends Exception {

            private static final long serialVersionUID = 1L;
        }

        @Override
        public SslSocketManager createManager(final String name, final SslFactoryData data) {
            InetAddress inetAddress = null;
            OutputStream os = null;
            Socket socket = null;

            try {
                inetAddress = resolveAddress(data.host);
                socket = createSocket(data);
                os = socket.getOutputStream();
                checkDelay(data.delayMillis, os);
            }
            catch (final IOException e) {
                LOGGER.error("SslSocketManager ({})", name, e);
                os = new ByteArrayOutputStream();
            }
            catch (final TlsSocketManagerFactoryException e) {
                LOGGER.catching(Level.DEBUG, e);
                return null;
            }
            return new SslSocketManager(name, os, socket, data.sslConfiguration, inetAddress, data.host, data.port, 0,
                    data.delayMillis, data.immediateFail, data.layout, data.bufferSize);
        }

        private InetAddress resolveAddress(final String hostName) throws TlsSocketManagerFactoryException {
            InetAddress address;

            try {
                address = InetAddress.getByName(hostName);
            } catch (final UnknownHostException ex) {
                LOGGER.error("Could not find address of {}", hostName, ex);
                throw new TlsSocketManagerFactoryException();
            }

            return address;
        }

        private void checkDelay(final int delay, final OutputStream os) throws TlsSocketManagerFactoryException {
            if (delay == 0 && os == null) {
                throw new TlsSocketManagerFactoryException();
            }
        }

        private Socket createSocket(final SslFactoryData data) throws IOException {
            SSLSocketFactory socketFactory;
            SSLSocket socket;

            socketFactory = createSslSocketFactory(data.sslConfiguration);
            socket = (SSLSocket) socketFactory.createSocket(data.host, data.port);
            return socket;
        }
    }
}
