/*

 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.net;

import java.io.IOException;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.util.HashMap;

import java.util.Map;

import java.util.Set;

/**

 * Basic SocketImpl that relies on the internal HTTP protocol handler

 * implementation to perform the HTTP tunneling and authentication. The

 * sockets impl is swapped out and replaced with the socket from the HTTP

 * handler after the tunnel is successfully setup.

 *

 * @since 1.8

 */

    private static final String httpURLClazzStr =

                                  "sun.net.www.protocol.http.HttpURLConnection";

    private static final String netClientClazzStr = "sun.net.NetworkClient";

    private static final String doTunnelingStr = "doTunneling";

    private static final Field httpField;

    private static final Field serverSocketField;

    private static final Method doTunneling;

    private final String server;

    private InetSocketAddress external_address;

    private HashMap<Integer, Object> optionsMap = new HashMap<>();

    static  {

        try {

            Class<?> httpClazz = Class.forName(httpURLClazzStr, true, null);

            httpField = httpClazz.getDeclaredField("http");

            doTunneling = httpClazz.getDeclaredMethod(doTunnelingStr);

            Class<?> netClientClazz = Class.forName(netClientClazzStr, true, null);

            serverSocketField = netClientClazz.getDeclaredField("serverSocket");

            java.security.AccessController.doPrivileged(

                new java.security.PrivilegedAction<>() {

                    public Void run() {

                        httpField.setAccessible(true);

                        serverSocketField.setAccessible(true);

                        return null;

                }

            });

        } catch (ReflectiveOperationException x) {

            throw new InternalError("Should not reach here", x);

        }

    }

    HttpConnectSocketImpl(Proxy proxy) {

        SocketAddress a = proxy.address();

        if ( !(a instanceof InetSocketAddress) )

            throw new IllegalArgumentException("Unsupported address type");

        InetSocketAddress ad = (InetSocketAddress) a;

        server = ad.getHostString();

        port = ad.getPort();

    }

    @Override

    protected void connect(SocketAddress endpoint, int timeout)

        throws IOException

    {

        if (endpoint == null || !(endpoint instanceof InetSocketAddress))

            throw new IllegalArgumentException("Unsupported address type");

        final InetSocketAddress epoint = (InetSocketAddress)endpoint;

        final String destHost = epoint.isUnresolved() ? epoint.getHostName()

                                                      : epoint.getAddress().getHostAddress();

        final int destPort = epoint.getPort();

        SecurityManager security = System.getSecurityManager();

        if (security != null)

            security.checkConnect(destHost, destPort);

        // Connect to the HTTP proxy server

        String urlString = "http://" + destHost + ":" + destPort;

        Socket httpSocket = privilegedDoTunnel(urlString, timeout);

        // Success!

        external_address = epoint;

        // close the original socket impl and release its descriptor

        close();

        // update the Sockets impl to the impl from the http Socket

        // best effort is made to try and reset options previously set

        Set<Map.Entry<Integer,Object>> options = optionsMap.entrySet();

        try {

            for(Map.Entry<Integer,Object> entry : options) {

            }

        } catch (IOException x) {  /* gulp! */  }

    }

    @Override

    public void setOption(int opt, Object val) throws SocketException {

        super.setOption(opt, val);

        if (external_address != null)

            return;  // we're connected, just return

        // store options so that they can be re-applied to the impl after connect

        optionsMap.put(opt, val);

    }

    private Socket privilegedDoTunnel(final String urlString,

                                      final int timeout)

        throws IOException

    {

        try {

            return java.security.AccessController.doPrivileged(

                new java.security.PrivilegedExceptionAction<>() {

                    public Socket run() throws IOException {

                        return doTunnel(urlString, timeout);

                }

            });

        } catch (java.security.PrivilegedActionException pae) {

            throw (IOException) pae.getException();

        }

    }

    private Socket doTunnel(String urlString, int connectTimeout)

        throws IOException

    {

        Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(server, port));

        URL destURL = new URL(urlString);

        HttpURLConnection conn = (HttpURLConnection) destURL.openConnection(proxy);

        conn.setConnectTimeout(connectTimeout);

        conn.connect();

        doTunneling(conn);

        try {

            Object httpClient = httpField.get(conn);

            return (Socket) serverSocketField.get(httpClient);

        } catch (IllegalAccessException x) {

            throw new InternalError("Should not reach here", x);

        }

    }

    private void doTunneling(HttpURLConnection conn) {

        try {

            doTunneling.invoke(conn);

        } catch (ReflectiveOperationException x) {

            throw new InternalError("Should not reach here", x);

        }

    }

    @Override

    protected InetAddress getInetAddress() {

        if (external_address != null)

            return external_address.getAddress();

        else

            return super.getInetAddress();

    }

    @Override

    protected int getPort() {

        if (external_address != null)

            return external_address.getPort();

        else

            return super.getPort();

    }

}