/*
 * 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/**
 * 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
 */

/*package*/ class HttpConnectSocketImpl extends PlainSocketImpl {

    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<Void>() {
                    public Void run() {
                        httpField.setAccessible(true);
                        serverSocketField.setAccessible(true);
                        return null;
                }
            });
        } catch (ReflectiveOperationException x) {
            throw new InternalError("Should not reach here", x);
        }
    }

    HttpConnectSocketImpl(String server, int port) {
        this.server = server;
        this.port = port;
    }

    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
        AbstractPlainSocketImpl psi = (AbstractPlainSocketImpl) httpSocket.impl;
        this.getSocket().impl = psi;

        // 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) {
                psi.setOption(entry.getKey(), entry.getValue());
            }
        } 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<Socket>() {
                    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.setReadTimeout(this.timeout);
        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();
    }

    @Override
    protected int getLocalPort() {
        if (socket != null)
            return super.getLocalPort();
        if (external_address != null)
            return external_address.getPort();
        else
            return super.getLocalPort();
    }
}