/*
 * 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
 * questions.
 */

package jdk.internal.net.http;

import jdk.internal.net.http.common.Utils;
import jdk.internal.net.http.websocket.RawChannel;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SocketChannel;
import java.util.function.Supplier;

/*
 * Each RawChannel corresponds to a TCP connection (SocketChannel) but is
 * connected to a Selector and an ExecutorService for invoking the send and
 * receive callbacks. Also includes SSL processing.
 */
final class RawChannelImpl implements RawChannel {

    private final HttpClientImpl client;
    private final HttpConnection.DetachedConnectionChannel detachedChannel;
    private final Object         initialLock = new Object();
    private Supplier<ByteBuffer> initial;

    RawChannelImpl(HttpClientImpl client,
                   HttpConnection connection,
                   Supplier<ByteBuffer> initial)
            throws IOException
    {
        this.client = client;
        this.detachedChannel = connection.detachChannel();
        this.initial = initial;

        SocketChannel chan = connection.channel();
        client.cancelRegistration(chan);
        // Constructing a RawChannel is supposed to have a "hand over"
        // semantics, in other words if construction fails, the channel won't be
        // needed by anyone, in which case someone still needs to close it
        try {
            chan.configureBlocking(false);
        } catch (IOException e) {
            try {
                chan.close();
            } catch (IOException e1) {
                e.addSuppressed(e1);
            } finally {
                detachedChannel.close();
            }
            throw e;
        }
    }

    private class NonBlockingRawAsyncEvent extends AsyncEvent {

        private final RawEvent re;

        NonBlockingRawAsyncEvent(RawEvent re) {
            // !BLOCKING & !REPEATING
            this.re = re;
        }

        @Override
        public SelectableChannel channel() {
            return detachedChannel.channel();
        }

        @Override
        public int interestOps() {
            return re.interestOps();
        }

        @Override
        public void handle() {
            re.handle();
        }

        @Override
        public void abort(IOException ioe) { }
    }

    @Override
    public void registerEvent(RawEvent event) throws IOException {
        client.registerEvent(new NonBlockingRawAsyncEvent(event));
    }

    @Override
    public ByteBuffer read() throws IOException {
        assert !detachedChannel.channel().isBlocking();
        // connection.read() will no longer be available.
        return detachedChannel.read();
    }

    @Override
    public ByteBuffer initialByteBuffer() {
        synchronized (initialLock) {
            if (initial == null) {
                throw new IllegalStateException();
            }
            ByteBuffer ref = initial.get();
            ref = ref.hasRemaining() ? Utils.copy(ref)
                    : Utils.EMPTY_BYTEBUFFER;
            initial = null;
            return ref;
        }
    }

    @Override
    public long write(ByteBuffer[] src, int offset, int len) throws IOException {
        // this makes the whitebox driver test fail.
        return detachedChannel.write(src, offset, len);
    }

    @Override
    public void shutdownInput() throws IOException {
        detachedChannel.shutdownInput();
    }

    @Override
    public void shutdownOutput() throws IOException {
        detachedChannel.shutdownOutput();
    }

    @Override
    public void close() {
        detachedChannel.close();
    }

    @Override
    public String toString() {
        return super.toString() + "(" + detachedChannel.toString() + ")";
    }
}