/*

 * Copyright (c) 2016, 2017, 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.

 *

 * 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.

 */

import java.io.*;

import java.nio.ByteBuffer;

/**

 * OutputStream. Incoming window updates handled by the main connection

 * reader thread.

 */

@SuppressWarnings({"rawtypes","unchecked"})

class BodyOutputStream extends OutputStream {

    final static byte[] EMPTY_BARRAY = new byte[0];

    final int streamid;

    int window;

    volatile boolean closed;

    boolean goodToGo = false; // not allowed to send until headers sent

    final Http2TestServerConnection conn;

    final Queue outputQ;

    BodyOutputStream(int streamid, int initialWindow, Http2TestServerConnection conn) {

        this.window = initialWindow;

        this.streamid = streamid;

        this.conn = conn;

        this.outputQ = conn.outputQ;

        conn.registerStreamWindowUpdater(streamid, this::updateWindow);

    }

    // called from connection reader thread as all incoming window

    // updates are handled there.

    synchronized void updateWindow(int update) {

        window += update;

        notifyAll();

    }

    void waitForWindow(int demand) throws InterruptedException {

        // first wait for the connection window

        conn.obtainConnectionWindow(demand);

        // now wait for the stream window

        synchronized (this) {

            while (demand > 0) {

                int n = Math.min(demand, window);

                demand -= n;

                window -= n;

                if (demand > 0) {

                    wait();

                }

            }

        }

    }

    void goodToGo() {

        goodToGo = true;

    }

    @Override

    public void write(byte[] buf, int offset, int len) throws IOException {

        if (closed) {

            throw new IOException("closed");

        }

        if (!goodToGo) {

            throw new IllegalStateException("sendResponseHeaders must be called first");

        }

        try {

            int max = conn.getMaxFrameSize();

            while (len > 0) {

                int n = len > max ? max : len;

                waitForWindow(n);

                send(buf, offset, n, 0);

                offset += n;

                len -= n;

            }

        } catch (InterruptedException ex) {

            throw new IOException(ex);

        }

    }

    private void send(byte[] buf, int offset, int len, int flags) throws IOException {

        ByteBuffer buffer = ByteBuffer.allocate(len);

        buffer.put(buf, offset, len);

        buffer.flip();

        assert streamid != 0;

        DataFrame df = new DataFrame(streamid, flags, buffer);

        outputQ.put(df);

    }

    byte[] one = new byte[1];

    @Override

    public void write(int b) throws IOException {

        one[0] = (byte) b;

        write(one, 0, 1);

    }

    void closeInternal() {

        closed = true;

    }

    @Override

    public void close() {

        if (closed) return;

        synchronized (this) {

            if (closed) return;

            closed = true;

        }

        try {

            send(EMPTY_BARRAY, 0, 0, DataFrame.END_STREAM);

        } catch (IOException ex) {

            System.err.println("TestServer: OutputStream.close exception: " + ex);

            ex.printStackTrace();

        }

    }

}