/*

 * Copyright (c) 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.

 *

 * 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

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 */

import java.io.IOException;

import java.nio.ByteBuffer;

import java.util.ArrayList;

import java.util.List;

import org.testng.Assert;

import org.testng.annotations.Test;

import static java.lang.System.out;

import static java.nio.charset.StandardCharsets.UTF_8;

import static org.testng.Assert.*;

public class FramesDecoderTest {

    abstract class TestFrameProcessor implements FramesDecoder.FrameProcessor {

        protected volatile int count;

        public int numberOfFramesDecoded() { return count; }

    }

    /**

     * Verifies that a ByteBuffer containing more that one frame, destined

     * to be returned to the user's subscriber, i.e. a data frame, does not

     * inadvertently expose the following frame ( between its limit and

     * capacity ).

     */

    @Test

    public void decodeDataFrameFollowedByAnother() throws Exception {

        // input frames for to the decoder

        List<ByteBuffer> data1 = List.of(ByteBuffer.wrap("XXXX".getBytes(UTF_8)));

        DataFrame dataFrame1 = new DataFrame(1, 0, data1);

        List<ByteBuffer> data2 = List.of(ByteBuffer.wrap("YYYY".getBytes(UTF_8)));

        DataFrame dataFrame2 = new DataFrame(1, 0, data2);

        List<ByteBuffer> buffers = new ArrayList<>();

        FramesEncoder encoder = new FramesEncoder();

        buffers.addAll(encoder.encodeFrame(dataFrame1));

        buffers.addAll(encoder.encodeFrame(dataFrame2));

        ByteBuffer combined = ByteBuffer.allocate(1024);

        buffers.stream().forEach(combined::put);

        combined.flip();

        TestFrameProcessor testFrameProcessor = new TestFrameProcessor() {

            @Override

            public void processFrame(Http2Frame frame) throws IOException {

                assertTrue(frame instanceof DataFrame);

                DataFrame dataFrame = (DataFrame) frame;

                List<ByteBuffer> list = dataFrame.getData();

                assertEquals(list.size(), 1);

                ByteBuffer data = list.get(0);

                byte[] bytes = new byte[data.remaining()];

                data.get(bytes);

                if (count == 0) {

                    assertEquals(new String(bytes, UTF_8), "XXXX");

                    out.println("First data received:" + data);

                    assertEquals(data.position(), data.limit());  // since bytes read

                    assertEquals(data.limit(), data.capacity());

                } else {

                    assertEquals(new String(bytes, UTF_8), "YYYY");

                    out.println("Second data received:" + data);

                }

                count++;

            }

        };

        FramesDecoder decoder = new FramesDecoder(testFrameProcessor);

        out.println("Sending " + combined + " to decoder: ");

        decoder.decode(combined);

        Assert.assertEquals(testFrameProcessor.numberOfFramesDecoded(), 2);

    }

    /**

     * Verifies that a ByteBuffer containing ONLY data one frame, destined

     * to be returned to the user's subscriber, does not restrict the capacity.

     * The complete buffer ( all its capacity ), since no longer used by the

     * HTTP Client, should be returned to the user.

     */

    @Test

    public void decodeDataFrameEnsureNotCapped() throws Exception {

        // input frames for to the decoder

        List<ByteBuffer> data1 = List.of(ByteBuffer.wrap("XXXX".getBytes(UTF_8)));

        DataFrame dataFrame1 = new DataFrame(1, 0, data1);

        List<ByteBuffer> buffers = new ArrayList<>();

        FramesEncoder encoder = new FramesEncoder();

        buffers.addAll(encoder.encodeFrame(dataFrame1));

        ByteBuffer combined = ByteBuffer.allocate(1024);

        buffers.stream().forEach(combined::put);

        combined.flip();

        TestFrameProcessor testFrameProcessor = new TestFrameProcessor() {

            @Override

            public void processFrame(Http2Frame frame) throws IOException {

                assertTrue(frame instanceof DataFrame);

                DataFrame dataFrame = (DataFrame) frame;

                List<ByteBuffer> list = dataFrame.getData();

                assertEquals(list.size(), 1);

                ByteBuffer data = list.get(0);

                byte[] bytes = new byte[data.remaining()];

                data.get(bytes);

                assertEquals(new String(bytes, UTF_8), "XXXX");

                out.println("First data received:" + data);

                assertEquals(data.position(), data.limit());  // since bytes read

                //assertNotEquals(data.limit(), data.capacity());

                assertEquals(data.capacity(), 1024 - 9 /*frame header*/);

                count++;

            }

        };

        FramesDecoder decoder = new FramesDecoder(testFrameProcessor);

        out.println("Sending " + combined + " to decoder: ");

        decoder.decode(combined);

        Assert.assertEquals(testFrameProcessor.numberOfFramesDecoded(), 1);

    }

}