/*

 * Copyright (c) 2015, 2018, 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

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 */

import java.io.IOException;

import java.lang.System.Logger.Level;

import java.net.InetSocketAddress;

import java.nio.ByteBuffer;

import java.nio.channels.SocketChannel;

import java.util.concurrent.CompletableFuture;

import java.util.function.Function;

import java.net.http.HttpHeaders;

import static java.net.http.HttpResponse.BodyHandler.discard;

/**

 * A plain text socket tunnel through a proxy. Uses "CONNECT" but does not

 * encrypt. Used by WebSocket, as well as HTTP over SSL + Proxy.

 * Wrapped in SSLTunnelConnection or AsyncSSLTunnelConnection for encryption.

 */

final class PlainTunnelingConnection extends HttpConnection {

    final PlainHttpConnection delegate;

    final HttpHeaders proxyHeaders;

    final InetSocketAddress proxyAddr;

    private volatile boolean connected;

    protected PlainTunnelingConnection(InetSocketAddress addr,

                                       InetSocketAddress proxy,

                                       HttpClientImpl client,

                                       HttpHeaders proxyHeaders) {

        super(addr, client);

        this.proxyAddr = proxy;

        this.proxyHeaders = proxyHeaders;

        delegate = new PlainHttpConnection(proxy, client);

    }

    @Override

    public CompletableFuture<Void> connectAsync() {

        debug.log(Level.DEBUG, "Connecting plain connection");

        return delegate.connectAsync()

            .thenCompose((Void v) -> {

                debug.log(Level.DEBUG, "sending HTTP/1.1 CONNECT");

                HttpClientImpl client = client();

                assert client != null;

                HttpRequestImpl req = new HttpRequestImpl("CONNECT", address, proxyHeaders);

                MultiExchange<Void> mulEx = new MultiExchange<>(null, req,

                        client, discard(), null, null);

                Exchange<Void> connectExchange = new Exchange<>(req, mulEx);

                return connectExchange

                        .responseAsyncImpl(delegate)

                        .thenCompose((Response resp) -> {

                            CompletableFuture<Void> cf = new MinimalFuture<>();

                            debug.log(Level.DEBUG, "got response: %d", resp.statusCode());

                            if (resp.statusCode() == 407) {

                                return connectExchange.ignoreBody().handle((r,t) -> {

                                    // close delegate after reading body: we won't

                                    // be reusing that connection anyway.

                                    delegate.close();

                                    ProxyAuthenticationRequired authenticationRequired =

                                            new ProxyAuthenticationRequired(resp);

                                    cf.completeExceptionally(authenticationRequired);

                                    return cf;

                                }).thenCompose(Function.identity());

                            } else if (resp.statusCode() != 200) {

                                delegate.close();

                                cf.completeExceptionally(new IOException(

                                        "Tunnel failed, got: "+ resp.statusCode()));

                            } else {

                                // get the initial/remaining bytes

                                ByteBuffer b = ((Http1Exchange<?>)connectExchange.exchImpl).drainLeftOverBytes();

                                int remaining = b.remaining();

                                assert remaining == 0: "Unexpected remaining: " + remaining;

                                connected = true;

                                cf.complete(null);

                            }

                            return cf;

                        });

            });

    }

    @Override

    boolean isTunnel() { return true; }

    @Override

    HttpPublisher publisher() { return delegate.publisher(); }

    @Override

    boolean connected() {

        return connected;

    }

    @Override

    SocketChannel channel() {

        return delegate.channel();

    }

    @Override

    FlowTube getConnectionFlow() {

        return delegate.getConnectionFlow();

    }

    @Override

    ConnectionPool.CacheKey cacheKey() {

        return new ConnectionPool.CacheKey(null, proxyAddr);

    }

    @Override

    public void close() {

        delegate.close();

        connected = false;

    }

    @Override

    void shutdownInput() throws IOException {

        delegate.shutdownInput();

    }

    @Override

    void shutdownOutput() throws IOException {

        delegate.shutdownOutput();

    }

    @Override

    boolean isSecure() {

        return false;

    }

    @Override

    boolean isProxied() {

        return true;

    }

    // Support for WebSocket/RawChannelImpl which unfortunately

    // still depends on synchronous read/writes.

    // It should be removed when RawChannelImpl moves to using asynchronous APIs.

    @Override

    DetachedConnectionChannel detachChannel() {

        return delegate.detachChannel();

    }

}