/*
  Copyright 2014 Larry Gritz and the other authors and contributors.
  All Rights Reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:
  * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
  * Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
  * Neither the name of the software's owners nor the names of its
    contributors may be used to endorse or promote products derived from
    this software without specific prior written permission.
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  (This is the Modified BSD License)
*/

extern "C" {  // ffmpeg is a C api
#include <cerrno>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57, 24, 0)
#    include <libavutil/imgutils.h>
#endif
}


#if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(55, 28, 1)
#    define av_frame_alloc avcodec_alloc_frame
//Ancient versions used av_freep
#    if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(54, 59, 100)
#        define av_frame_free av_freep
#    else
#        define av_frame_free avcodec_free_frame
#    endif
#endif

// PIX_FMT was renamed to AV_PIX_FMT on this version
#if LIBAVUTIL_VERSION_INT < AV_VERSION_INT(51, 74, 100)
#    define AVPixelFormat PixelFormat
#    define AV_PIX_FMT_RGB24 PIX_FMT_RGB24
#    define AV_PIX_FMT_RGB48 PIX_FMT_RGB48
#    define AV_PIX_FMT_YUVJ420P PIX_FMT_YUVJ420P
#    define AV_PIX_FMT_YUVJ422P PIX_FMT_YUVJ422P
#    define AV_PIX_FMT_YUVJ440P PIX_FMT_YUVJ440P
#    define AV_PIX_FMT_YUVJ444P PIX_FMT_YUVJ444P
#    define AV_PIX_FMT_YUV420P PIX_FMT_YUV420P
#    define AV_PIX_FMT_YUV422P PIX_FMT_YUV422P
#    define AV_PIX_FMT_YUV440P PIX_FMT_YUV440P
#    define AV_PIX_FMT_YUV444P PIX_FMT_YUV444P
#endif

// r_frame_rate deprecated in ffmpeg
// see ffmpeg commit #aba232c for details
#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(52, 42, 0)
#    define r_frame_rate avg_frame_rate
#endif

// Changes for ffmpeg 3.0
#define USE_FFMPEG_3_0 (LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57, 24, 0))

#if USE_FFMPEG_3_0
#    define av_free_packet av_packet_unref
#    define avpicture_get_size(fmt, w, h) av_image_get_buffer_size(fmt, w, h, 1)

inline int
avpicture_fill(AVPicture* picture, uint8_t* ptr, enum AVPixelFormat pix_fmt,
               int width, int height)
{
    AVFrame* frame = reinterpret_cast<AVFrame*>(picture);
    return av_image_fill_arrays(frame->data, frame->linesize, ptr, pix_fmt,
                                width, height, 1);
}
#endif

// Changes for ffmpeg 3.1
#define USE_FFMPEG_3_1 (LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57, 48, 101))

#if USE_FFMPEG_3_1
// AVStream::codec was changed to AVStream::codecpar
#    define stream_codec(ix) m_format_context->streams[(ix)]->codecpar
// avcodec_decode_video2 was deprecated.
// This now works by sending `avpkt` to the decoder, which buffers the
// decoded image in `avctx`. Then `avcodec_receive_frame` will copy the
// frame to `picture`.
inline int
receive_frame(AVCodecContext* avctx, AVFrame* picture, AVPacket* avpkt)
{
    int ret;

    ret = avcodec_send_packet(avctx, avpkt);

    if (ret < 0)
        return 0;

    ret = avcodec_receive_frame(avctx, picture);

    if (ret < 0)
        return 0;

    return 1;
}
#else
#    define stream_codec(ix) m_format_context->streams[(ix)]->codec
inline int
receive_frame(AVCodecContext* avctx, AVFrame* picture, AVPacket* avpkt)
{
    int ret;
    avcodec_decode_video2(avctx, picture, &ret, avpkt);
    return ret;
}
#endif


// Changes for ffmpeg 4.0
#define USE_FFMPEG_4_0 (LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(58, 18, 100))

#if (LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(56, 56, 100))
#    define CODEC_CAP_DELAY AV_CODEC_CAP_DELAY
#endif


#include <OpenImageIO/imageio.h>
#include <iostream>
#include <mutex>

OIIO_PLUGIN_NAMESPACE_BEGIN


class FFmpegInput final : public ImageInput {
public:
    FFmpegInput();
    virtual ~FFmpegInput();
    virtual const char* format_name(void) const override
    {
        return "FFmpeg movie";
    }
    virtual bool open(const std::string& name, ImageSpec& spec) override;
    virtual bool close(void) override;
    virtual int current_subimage(void) const override
    {
        lock_guard lock(m_mutex);
        return m_subimage;
    }
    virtual bool seek_subimage(int subimage, int miplevel) override;
    virtual bool read_native_scanline(int subimage, int miplevel, int y, int z,
                                      void* data) override;
    void read_frame(int pos);
#if 0
    const char *metadata (const char * key);
    bool has_metadata (const char * key);
#endif
    bool seek(int pos);
    double fps() const;
    int64_t time_stamp(int pos) const;

private:
    std::string m_filename;
    int m_subimage;
    int64_t m_nsubimages;
    AVFormatContext* m_format_context;
    AVCodecContext* m_codec_context;
    AVCodec* m_codec;
    AVFrame* m_frame;
    AVFrame* m_rgb_frame;
    size_t m_stride;
    AVPixelFormat m_dst_pix_format;
    SwsContext* m_sws_rgb_context;
    AVRational m_frame_rate;
    std::vector<uint8_t> m_rgb_buffer;
    std::vector<int> m_video_indexes;
    int m_video_stream;
    int64_t m_frames;
    int m_last_search_pos;
    int m_last_decoded_pos;
    bool m_offset_time;
    bool m_codec_cap_delay;
    bool m_read_frame;
    int64_t m_start_time;

    // init to initialize state
    void init(void)
    {
        m_filename.clear();
        m_format_context  = 0;
        m_codec_context   = 0;
        m_codec           = 0;
        m_frame           = 0;
        m_rgb_frame       = 0;
        m_sws_rgb_context = 0;
        m_stride          = 0;
        m_rgb_buffer.clear();
        m_video_indexes.clear();
        m_video_stream     = -1;
        m_frames           = 0;
        m_last_search_pos  = 0;
        m_last_decoded_pos = 0;
        m_offset_time      = true;
        m_read_frame       = false;
        m_codec_cap_delay  = false;
        m_subimage         = 0;
        m_start_time       = 0;
    }
};



// Obligatory material to make this a recognizeable imageio plugin
OIIO_PLUGIN_EXPORTS_BEGIN

OIIO_EXPORT int ffmpeg_imageio_version = OIIO_PLUGIN_VERSION;
OIIO_EXPORT const char*
ffmpeg_imageio_library_version()
{
    return "FFMpeg " LIBAVFORMAT_IDENT;
}
OIIO_EXPORT ImageInput*
ffmpeg_input_imageio_create()
{
    return new FFmpegInput;
}
// FFmpeg hints:
// AVI (Audio Video Interleaved)
// QuickTime / MOV
// raw MPEG-4 video
// MPEG-1 Systems / MPEG program stream
OIIO_EXPORT const char* ffmpeg_input_extensions[] = {
    "avi", "mov", "qt", "mp4", "m4a", "3gp", "3g2", "mj2", "m4v", "mpg", nullptr
};


OIIO_PLUGIN_EXPORTS_END



FFmpegInput::FFmpegInput() { init(); }



FFmpegInput::~FFmpegInput() { close(); }



bool
FFmpegInput::open(const std::string& name, ImageSpec& spec)
{
    // Temporary workaround: refuse to open a file whose name does not
    // indicate that it's a movie file. This avoids the problem that ffmpeg
    // is willing to open tiff and other files better handled by other
    // plugins. The better long-term solution is to replace av_register_all
    // with our own function that registers only the formats that we want
    // this reader to handle. At some point, we will institute that superior
    // approach, but in the mean time, this is a quick solution that 90%
    // does the job.
    bool valid_extension = false;
    for (int i = 0; ffmpeg_input_extensions[i]; ++i)
        if (Strutil::ends_with(name, ffmpeg_input_extensions[i])) {
            valid_extension = true;
            break;
        }
    if (!valid_extension) {
        error("\"%s\" could not open input", name);
        return false;
    }

    static std::once_flag init_flag;
    std::call_once(init_flag, av_register_all);
    const char* file_name = name.c_str();
    av_log_set_level(AV_LOG_FATAL);
    if (avformat_open_input(&m_format_context, file_name, NULL, NULL)
        != 0)  // avformat_open_input allocs format_context
    {
        error("\"%s\" could not open input", file_name);
        return false;
    }
    if (avformat_find_stream_info(m_format_context, NULL) < 0) {
        error("\"%s\" could not find stream info", file_name);
        return false;
    }
    m_video_stream = -1;
    for (unsigned int i = 0; i < m_format_context->nb_streams; i++) {
        if (stream_codec(i)->codec_type == AVMEDIA_TYPE_VIDEO) {
            if (m_video_stream < 0) {
                m_video_stream = i;
            }
            m_video_indexes.push_back(i);  // needed for later use
            break;
        }
    }
    if (m_video_stream == -1) {
        error("\"%s\" could not find a valid videostream", file_name);
        return false;
    }

    // codec context for videostream
#if USE_FFMPEG_3_1
    AVCodecParameters* par = stream_codec(m_video_stream);

    m_codec = avcodec_find_decoder(par->codec_id);
    if (!m_codec) {
        error("\"%s\" can't find decoder", file_name);
        return false;
    }

    m_codec_context = avcodec_alloc_context3(m_codec);
    if (!m_codec_context) {
        error("\"%s\" can't allocate decoder context", file_name);
        return false;
    }

    int ret;

    ret = avcodec_parameters_to_context(m_codec_context, par);
    if (ret < 0) {
        error("\"%s\" unsupported codec", file_name);
        return false;
    }
#else
    m_codec_context = stream_codec(m_video_stream);

    m_codec = avcodec_find_decoder(m_codec_context->codec_id);
    if (!m_codec) {
        error("\"%s\" unsupported codec", file_name);
        return false;
    }
#endif

    if (avcodec_open2(m_codec_context, m_codec, NULL) < 0) {
        error("\"%s\" could not open codec", file_name);
        return false;
    }
    if (!strcmp(m_codec_context->codec->name, "mjpeg")
        || !strcmp(m_codec_context->codec->name, "dvvideo")) {
        m_offset_time = false;
    }
    m_codec_cap_delay = (bool)(m_codec_context->codec->capabilities
                               & CODEC_CAP_DELAY);

    AVStream* stream = m_format_context->streams[m_video_stream];
    if (stream->r_frame_rate.num != 0 && stream->r_frame_rate.den != 0) {
        m_frame_rate = stream->r_frame_rate;
    }

    m_frames     = stream->nb_frames;
    m_start_time = stream->start_time;
    if (!m_frames) {
        seek(0);
        AVPacket pkt;
        av_init_packet(&pkt);
        av_read_frame(m_format_context, &pkt);
        int64_t first_pts = pkt.pts;
        int64_t max_pts   = 0;
        av_free_packet(&pkt);  //because seek(int) uses m_format_context
        seek(1 << 29);
        av_init_packet(&pkt);  //Is this needed?
        while (stream && av_read_frame(m_format_context, &pkt) >= 0) {
            int64_t current_pts = static_cast<int64_t>(
                av_q2d(stream->time_base) * (pkt.pts - first_pts) * fps());
            if (current_pts > max_pts) {
                max_pts = current_pts + 1;
            }
            av_free_packet(&pkt);  //Always free before format_context usage
        }
        m_frames = max_pts;
    }
    m_frame     = av_frame_alloc();
    m_rgb_frame = av_frame_alloc();

    AVPixelFormat src_pix_format;
    switch (m_codec_context->pix_fmt) {  // deprecation warning for YUV formats
    case AV_PIX_FMT_YUVJ420P: src_pix_format = AV_PIX_FMT_YUV420P; break;
    case AV_PIX_FMT_YUVJ422P: src_pix_format = AV_PIX_FMT_YUV422P; break;
    case AV_PIX_FMT_YUVJ444P: src_pix_format = AV_PIX_FMT_YUV444P; break;
    case AV_PIX_FMT_YUVJ440P: src_pix_format = AV_PIX_FMT_YUV440P; break;
    default: src_pix_format = m_codec_context->pix_fmt; break;
    }

    m_spec = ImageSpec(m_codec_context->width, m_codec_context->height, 3);

    switch (src_pix_format) {
    // support for 10-bit and 12-bit pix_fmts
    case AV_PIX_FMT_YUV420P10BE:
    case AV_PIX_FMT_YUV420P10LE:
    case AV_PIX_FMT_YUV422P10BE:
    case AV_PIX_FMT_YUV422P10LE:
    case AV_PIX_FMT_YUV444P10BE:
    case AV_PIX_FMT_YUV444P10LE:
    case AV_PIX_FMT_YUV420P12BE:
    case AV_PIX_FMT_YUV420P12LE:
    case AV_PIX_FMT_YUV422P12BE:
    case AV_PIX_FMT_YUV422P12LE:
    case AV_PIX_FMT_YUV444P12BE:
    case AV_PIX_FMT_YUV444P12LE:
        m_spec.set_format(TypeDesc::UINT16);
        m_dst_pix_format = AV_PIX_FMT_RGB48;
        m_stride         = (size_t)(m_spec.width * 3 * 2);
        break;
    default:
        m_spec.set_format(TypeDesc::UINT8);
        m_dst_pix_format = AV_PIX_FMT_RGB24;
        m_stride         = (size_t)(m_spec.width * 3);
        break;
    }

    m_rgb_buffer.resize(avpicture_get_size(m_dst_pix_format,
                                           m_codec_context->width,
                                           m_codec_context->height),
                        0);

    m_sws_rgb_context
        = sws_getContext(m_codec_context->width, m_codec_context->height,
                         src_pix_format, m_codec_context->width,
                         m_codec_context->height, m_dst_pix_format, SWS_AREA,
                         NULL, NULL, NULL);

    AVDictionaryEntry* tag = NULL;
    while ((tag = av_dict_get(m_format_context->metadata, "", tag,
                              AV_DICT_IGNORE_SUFFIX))) {
        m_spec.attribute(tag->key, tag->value);
    }
    int rat[2] = { m_frame_rate.num, m_frame_rate.den };
    m_spec.attribute("FramesPerSecond", TypeRational, &rat);
    m_spec.attribute("oiio:Movie", true);
    m_spec.attribute("oiio:BitsPerSample",
                     m_codec_context->bits_per_raw_sample);
    m_nsubimages = m_frames;
    spec         = m_spec;
    return true;
}



bool
FFmpegInput::seek_subimage(int subimage, int miplevel)
{
    if (subimage < 0 || subimage >= m_nsubimages || miplevel > 0) {
        return false;
    }
    if (subimage == m_subimage) {
        return true;
    }
    m_subimage   = subimage;
    m_read_frame = false;
    return true;
}



bool
FFmpegInput::read_native_scanline(int subimage, int miplevel, int y, int z,
                                  void* data)
{
    lock_guard lock(m_mutex);
    if (!seek_subimage(subimage, miplevel))
        return false;
    if (!m_read_frame) {
        read_frame(m_subimage);
    }
    memcpy(data, m_rgb_frame->data[0] + y * m_rgb_frame->linesize[0], m_stride);
    return true;
}



bool
FFmpegInput::close(void)
{
    if (m_codec_context)
        avcodec_close(m_codec_context);
    if (m_format_context)
        avformat_close_input(&m_format_context);
    av_free(m_format_context);  // will free m_codec and m_codec_context
    av_frame_free(&m_frame);    // free after close input
    av_frame_free(&m_rgb_frame);
    sws_freeContext(m_sws_rgb_context);
    init();
    return true;
}



void
FFmpegInput::read_frame(int frame)
{
    if (m_last_decoded_pos + 1 != frame) {
        seek(frame);
    }
    AVPacket pkt;
    int finished = 0;
    int ret      = 0;
    while ((ret = av_read_frame(m_format_context, &pkt)) == 0
           || m_codec_cap_delay) {
        if (pkt.stream_index == m_video_stream) {
            if (ret < 0 && m_codec_cap_delay) {
                pkt.data = NULL;
                pkt.size = 0;
            }

            finished = receive_frame(m_codec_context, m_frame, &pkt);

            double pts = 0;
            if (static_cast<int64_t>(m_frame->pkt_pts)
                != int64_t(AV_NOPTS_VALUE)) {
                pts = av_q2d(
                          m_format_context->streams[m_video_stream]->time_base)
                      * m_frame->pkt_pts;
            }

            int current_frame = int((pts - m_start_time) * fps() + 0.5f);  //???
            //current_frame =   m_frame->display_picture_number;
            m_last_search_pos = current_frame;

            if (current_frame == frame && finished) {
                avpicture_fill(reinterpret_cast<AVPicture*>(m_rgb_frame),
                               &m_rgb_buffer[0], m_dst_pix_format,
                               m_codec_context->width, m_codec_context->height);
                sws_scale(m_sws_rgb_context,
                          static_cast<uint8_t const* const*>(m_frame->data),
                          m_frame->linesize, 0, m_codec_context->height,
                          m_rgb_frame->data, m_rgb_frame->linesize);
                m_last_decoded_pos = current_frame;
                av_free_packet(&pkt);
                break;
            }
        }
        av_free_packet(&pkt);
    }
    m_read_frame = true;
}



#if 0
const char *
FFmpegInput::metadata (const char * key)
{
    AVDictionaryEntry * entry = av_dict_get (m_format_context->metadata, key, NULL, 0);
    return entry ? av_strdup(entry->value) : NULL;
    // FIXME -- that looks suspiciously like a memory leak
}



bool
FFmpegInput::has_metadata (const char * key)
{
    return av_dict_get (m_format_context->metadata, key, NULL, 0); // is there a better to check exists?
}
#endif



bool
FFmpegInput::seek(int frame)
{
    int64_t offset = time_stamp(frame);
    int flags      = AVSEEK_FLAG_BACKWARD;
    avcodec_flush_buffers(m_codec_context);
    av_seek_frame(m_format_context, -1, offset, flags);
    return true;
}



int64_t
FFmpegInput::time_stamp(int frame) const
{
    int64_t timestamp = static_cast<int64_t>(
        (static_cast<double>(frame)
         / (fps()
            * av_q2d(m_format_context->streams[m_video_stream]->time_base))));
    if (static_cast<int64_t>(m_format_context->start_time)
        != int64_t(AV_NOPTS_VALUE)) {
        timestamp += static_cast<int64_t>(
            static_cast<double>(m_format_context->start_time) * AV_TIME_BASE
            / av_q2d(m_format_context->streams[m_video_stream]->time_base));
    }
    return timestamp;
}



double
FFmpegInput::fps() const
{
    if (m_frame_rate.den) {
        return av_q2d(m_frame_rate);
    }
    return 1.0f;
}

OIIO_PLUGIN_NAMESPACE_END