/*
Copyright 2017-2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License"). 
You may not use this file except in compliance with the License. 
A copy of the License is located at

   http://aws.amazon.com/apache2.0/

or in the "license" file accompanying this file. 
This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and limitations under the License.
*/
package com.amazonaws.kinesisvideo.parser.utilities;

import com.amazonaws.kinesisvideo.parser.mkv.Frame;
import com.amazonaws.kinesisvideo.parser.mkv.FrameProcessException;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.jcodec.codecs.h264.H264Decoder;
import org.jcodec.codecs.h264.mp4.AvcCBox;
import org.jcodec.common.model.ColorSpace;
import org.jcodec.common.model.Picture;
import org.jcodec.scale.AWTUtil;
import org.jcodec.scale.Transform;
import org.jcodec.scale.Yuv420jToRgb;

import java.awt.image.BufferedImage;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Optional;

import static org.jcodec.codecs.h264.H264Utils.splitMOVPacket;

/**
 * H264 Frame Decoder class which uses JCodec decoder to decode frames.
 */
@Slf4j
public class H264FrameDecoder implements FrameVisitor.FrameProcessor  {

    private final H264Decoder decoder = new H264Decoder();
    private final Transform transform = new Yuv420jToRgb();

    @Getter
    private int frameCount;

    private byte[] codecPrivateData;

    @Override
    public void process(final Frame frame, final MkvTrackMetadata trackMetadata,
                        final Optional<FragmentMetadata> fragmentMetadata) throws FrameProcessException {
        decodeH264Frame(frame, trackMetadata);
    }

    public BufferedImage decodeH264Frame(final Frame frame, final MkvTrackMetadata trackMetadata) {
        final ByteBuffer frameBuffer = frame.getFrameData();
        final int pixelWidth = trackMetadata.getPixelWidth().get().intValue();
        final int pixelHeight = trackMetadata.getPixelHeight().get().intValue();
        codecPrivateData = trackMetadata.getCodecPrivateData().array();
        log.debug("Decoding frames ... ");
        // Read the bytes that appear to comprise the header
        // See: https://www.matroska.org/technical/specs/index.html#simpleblock_structure

        final Picture rgb = Picture.create(pixelWidth, pixelHeight, ColorSpace.RGB);
        final BufferedImage bufferedImage = new BufferedImage(pixelWidth, pixelHeight, BufferedImage.TYPE_3BYTE_BGR);
        final AvcCBox avcC = AvcCBox.parseAvcCBox(ByteBuffer.wrap(codecPrivateData));

        decoder.addSps(avcC.getSpsList());
        decoder.addPps(avcC.getPpsList());

        final Picture buf = Picture.create(pixelWidth + ((16 - (pixelWidth % 16)) % 16),
                pixelHeight + ((16 - (pixelHeight % 16)) % 16), ColorSpace.YUV420J);
        final List<ByteBuffer> byteBuffers = splitMOVPacket(frameBuffer, avcC);
        final Picture pic = decoder.decodeFrameFromNals(byteBuffers, buf.getData());

        if (pic != null) {
            // Work around for color issues in JCodec
            // https://github.com/jcodec/jcodec/issues/59
            // https://github.com/jcodec/jcodec/issues/192
            final byte[][] dataTemp = new byte[3][pic.getData().length];
            dataTemp[0] = pic.getPlaneData(0);
            dataTemp[1] = pic.getPlaneData(2);
            dataTemp[2] = pic.getPlaneData(1);

            final Picture tmpBuf = Picture.createPicture(pixelWidth, pixelHeight, dataTemp, ColorSpace.YUV420J);
            transform.transform(tmpBuf, rgb);
            AWTUtil.toBufferedImage(rgb, bufferedImage);
            frameCount++;
        }
        return bufferedImage;
    }

    public ByteBuffer getCodecPrivateData() {
        return ByteBuffer.wrap(codecPrivateData);
    }
}