extern "C"
{
  #include "lib/libavcodec/avcodec.h"
  #include "lib/libavformat/avformat.h"
  #include "lib/libavutil/avutil.h"
  #include "lib/libavutil/imgutils.h"
  #include "lib/libswscale/swscale.h"
  #include "lib/libswresample/swresample.h"
  #include "lib/libavutil/opt.h"
  //#include "libavutil/samplefmt.h"
}
#pragma comment(lib, "avcodec.lib")
#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "swscale.lib")
#pragma comment(lib, "swresample.lib")

#include <vector>
#include <deque>

#include "stuff.h"
#include "OpenALSoundProvider.h"

#include "MediaPlayer.h"
using namespace Media;




class MemoryStream
{
  public:
    inline MemoryStream(void *data, size_t data_size)
    {
      this->data_size = data_size;
      this->data = data;
      this->current_pos = 0;
    }
    inline MemoryStream()
    {
      this->data_size = 0;
      this->data = nullptr;
      this->current_pos = 0;
    }

    inline ~MemoryStream()
    {
      if (data)
        delete [] data;
    }

    inline size_t Write(void *buffer, size_t num_bytes)
    {
      if (!data)
      {
        data_size = 32 + num_bytes;
        data = new char[data_size];
        current_pos = 0;
      }
      else if (current_pos + num_bytes >= data_size)
      {
        int  new_data_size = data_size + num_bytes + data_size / 8 + 4;
        auto new_data = new char[new_data_size];

        memcpy(new_data, data, data_size);
        delete [] data;
        
        data_size = new_data_size;
        data = new_data;
      }
      memcpy((char *)data + current_pos, buffer, num_bytes);
      current_pos += num_bytes;
      return num_bytes;
    }

    inline size_t Read(void *buffer, size_t num_bytes)
    {
      size_t read_size = min(num_bytes, data_size - current_pos);
      if (read_size)
      {
        memcpy(buffer, (char *)data + current_pos, read_size);
        current_pos += read_size;
      }
      return read_size;
    }

    inline void Reset()
    {
      current_pos = 0;
    }
    inline void SeekToEnd()
    {
      current_pos = data_size;
    }

    inline size_t Unwind(size_t bytes)
    {
      if (bytes > current_pos)
        current_pos = 0;
      else
        current_pos -= bytes;
      return current_pos;
    }
    
    inline size_t Rewind(size_t bytes)
    {
      if (current_pos + bytes >= data_size)
        current_pos = data_size;
      else
        current_pos += bytes;
      return current_pos;
    }

    inline size_t  Size() const    {return data_size;}
    inline size_t  Current() const {return current_pos;}
    inline void   *Ptr() const     {return data;}

  private:
    void   *data;
    size_t  data_size;
    size_t  current_pos;
};




OpenALSoundProvider *provider = nullptr;



static int av_num_bytes_per_sample(AVSampleFormat sample_fmt)
{
  switch (sample_fmt)
  {
    case AV_SAMPLE_FMT_U8:
    case AV_SAMPLE_FMT_U8P:
      return 1;
          
    case AV_SAMPLE_FMT_S16:
    case AV_SAMPLE_FMT_S16P:
      return 2;

    case AV_SAMPLE_FMT_S32:
    case AV_SAMPLE_FMT_S32P:
    case AV_SAMPLE_FMT_FLT:
    case AV_SAMPLE_FMT_FLTP:
      return 4;

    case AV_SAMPLE_FMT_DBL:
    case AV_SAMPLE_FMT_DBLP:
      return 8;

    default:
    case AV_SAMPLE_FMT_NONE:
      Error("Invalid av sample format: %u", sample_fmt);
  }
  return 0;
}



struct AVStreamWrapper
{
  inline AVStreamWrapper()
  {
    this->type = AVMEDIA_TYPE_UNKNOWN;
    this->stream_idx = -1;
    this->stream = nullptr;
    this->dec = nullptr;
    this->dec_ctx = nullptr;
  }

  inline void Release()
  {
    type = AVMEDIA_TYPE_UNKNOWN;
    stream_idx = -1;
    stream = nullptr;
    dec = nullptr;
    if (dec_ctx)
    {
      avcodec_close(dec_ctx);
      dec_ctx = nullptr;
    }
  }

  AVMediaType      type;
  int              stream_idx;
  AVStream        *stream;
  AVCodec         *dec;
  AVCodecContext  *dec_ctx;
};

struct AVAudioStream: public AVStreamWrapper
{
  inline AVAudioStream():
    AVStreamWrapper()
  {
    this->bytes_per_sample = 0;
    this->bytes_per_second = 0;
  }

  int bytes_per_sample;
  int bytes_per_second;
};

struct AVVideoStream: public AVStreamWrapper
{
  inline AVVideoStream():
    AVStreamWrapper()
  {
    this->frames_per_second = 0.0;
  }

  double frames_per_second;
};

static bool av_open_stream(AVFormatContext *format_ctx, AVMediaType type, AVStreamWrapper *out_stream)
{
  int stream_idx = av_find_best_stream(format_ctx, type, -1, -1, nullptr, 0);
  if (stream_idx >= 0)
  {
    auto stream = format_ctx->streams[stream_idx];
    auto dec_ctx = stream->codec;
    auto dec = avcodec_find_decoder(dec_ctx->codec_id);
    if (dec)
    {
      if (avcodec_open2(dec_ctx, dec, nullptr) >= 0)
      {
        out_stream->type = type;
        out_stream->stream_idx = stream_idx;
        out_stream->stream = stream;
        out_stream->dec = dec;
        out_stream->dec_ctx = dec_ctx;
        return true;
      }
    }
  }
  return false;
}

static bool av_open_audio_stream(AVFormatContext *format_ctx, AVAudioStream *out_stream)
{
  if (!av_open_stream(format_ctx, AVMEDIA_TYPE_AUDIO, out_stream))
    return Error("Audio stream not found"), false;
  
  // we support only 2-channel audio for now
  if (out_stream->dec_ctx->channels != 2)
  {
    out_stream->Release();
    return Error("Unsupported number of channels: %u", out_stream->dec_ctx->channels), false;
  }
  
  out_stream->bytes_per_sample = av_num_bytes_per_sample(out_stream->dec_ctx->sample_fmt);
  out_stream->bytes_per_second = out_stream->dec_ctx->channels * out_stream->dec_ctx->sample_rate * out_stream->bytes_per_sample;

  return true;
}

static bool av_open_video_stream(AVFormatContext *format_ctx, AVVideoStream *out_stream)
{
  if (!av_open_stream(format_ctx, AVMEDIA_TYPE_VIDEO, out_stream))
    return Error("Video stream not found"), false;

  out_stream->frames_per_second = (double)out_stream->dec_ctx->time_base.den / (double)out_stream->dec_ctx->time_base.num;
  return true;
}



void InterleaveAudioData(MemoryStream *stream, AVSampleFormat src_format, int num_channels, int num_samples, uint8_t **channels)
{
  unsigned int bytes_per_sample;
  switch (src_format)
  {
    case AV_SAMPLE_FMT_U8:
    case AV_SAMPLE_FMT_U8P:
      __debugbreak();

    case AV_SAMPLE_FMT_S16:
      bytes_per_sample = sizeof(__int16);
      stream->Write(channels[0], num_channels * num_samples * bytes_per_sample);
    break;

    case AV_SAMPLE_FMT_S16P:
    {
      bytes_per_sample = sizeof(__int16);
      for (int i = 0; i < num_samples; ++i)
        for (int j = 0; j < num_channels; ++j)
          stream->Write(channels[j] + i * bytes_per_sample, bytes_per_sample);
    }
    break;

    case AV_SAMPLE_FMT_FLT:
    {
      SwrContext *converter = swr_alloc();
      av_opt_set_int(converter, "in_channel_layout",    av_get_default_channel_layout(2), 0);
      //av_opt_set_int(converter, "in_sample_rate",       sample_ra, 0);
      av_opt_set_sample_fmt(converter, "in_sample_fmt", AV_SAMPLE_FMT_FLT, 0);

      av_opt_set_int(converter, "out_channel_layout",    av_get_default_channel_layout(2), 0);
      //av_opt_set_int(converter, "out_sample_rate",       dst_sample_rate, 0);
      av_opt_set_sample_fmt(converter, "out_sample_fmt", AV_SAMPLE_FMT_S16, 0);

      if (swr_init(converter) < 0)
      {
        __debugbreak();
        swr_free(&converter);
        return;
      }

      uint8_t **dst_channels;
      int       dst_linesize[8];
      //int dst_nb_channels = av_get_channel_layout_nb_channels(dst_channel_layout);
      if (av_samples_alloc_array_and_samples(&dst_channels, dst_linesize, 2, num_channels * num_samples, AV_SAMPLE_FMT_S16, 0) < 0)
      {
        __debugbreak();
        swr_free(&converter);
        return;
      }

      if (swr_convert(converter, dst_channels, num_channels * num_samples, (const uint8_t **)channels, num_channels * num_samples) >= 0)
        stream->Write(dst_channels[0], num_channels * num_samples * sizeof(__int16));
      else
        __debugbreak();

      av_free(dst_channels[0]);
      swr_free(&converter);
    }
    break;

    default:
      __debugbreak();
      //if (Resample(next_frame->avframe, next_frame->avframe->channel_layout, next_frame->avframe->sample_rate,
      //                                            av_get_default_channel_layout(2),    next_frame->avframe->sample_rate, AV_SAMPLE_FMT_S16P, resampled_data))
  }
}



bool DecodeAudioFrame(AVCodecContext *dec_ctx, AVPacket *avpacket, AVFrame *avframe, MemoryStream *out_audio_data, int *out_num_audio_samples)
{
  volatile int decoded = false;
  do
  {
    if (avcodec_decode_audio4(dec_ctx, avframe, (int *)&decoded, avpacket) < 0)
    {
      log("Cannot decode audio frame\n");
      return false;
    }

    if (!decoded)
      log("Cannot decode audio frame in one piece\n");
  } while (!decoded);

  switch (dec_ctx->codec_id)
  {
    case AV_CODEC_ID_BINKAUDIO_RDFT:
    {//pts	samples		dpts
     //    0	960
     //17280	960		17280    18x960
     //18240	960		960       1x960
     //20160	960		1920      2x960
     //21120	960		960       1x960
     //23040	960		1920      2x960
      static int bink_next_pts = 0;

        // there's a gap in the sound - fill empty samples in
      if (bink_next_pts < avpacket->pts)
      {
        short silence[1024];
        memset(silence, 0, sizeof(silence));

        int samples_to_fill = /*dec_ctx->channels * */(avpacket->pts - bink_next_pts);
        while (samples_to_fill > 0)
        {
          int samples_to_fill_this_step = samples_to_fill >= 1024 ? 1024 : samples_to_fill;
          out_audio_data->Write(silence, samples_to_fill_this_step  * sizeof(short));

          samples_to_fill -= samples_to_fill_this_step;
        }
      }

      bink_next_pts = avpacket->pts + /*dec_ctx->channels * */avframe->nb_samples;
    }
    break;
                /*
      case AV_CODEC_ID_SMACKAUDIO:
      {
        static int smack_debug_next_audio_time = 0;
        if (smack_debug_next_audio_time != packet->pts)
        {
          Error("There's a gap in the sound before frame %u\n", num_audio_frames);
          __debugbreak(); // there's a gap in the sound
        }

        int num_actual_data_channels = 0;
        switch (dec_ctx->sample_fmt)
        {
          case AV_SAMPLE_FMT_U8:
          case AV_SAMPLE_FMT_S16:
          case AV_SAMPLE_FMT_S32:
          case AV_SAMPLE_FMT_FLT:
          case AV_SAMPLE_FMT_DBL:
            num_actual_data_channels = 1;
          break;

          case AV_SAMPLE_FMT_U8P:
          case AV_SAMPLE_FMT_S16P:
          case AV_SAMPLE_FMT_S32P:
          case AV_SAMPLE_FMT_FLTP:
          case AV_SAMPLE_FMT_DBLP:
            num_actual_data_channels = dec_ctx->channels;
          break;

          default:
          case AV_SAMPLE_FMT_NONE:
          case AV_SAMPLE_FMT_NB:
            __debugbreak();
        }

        smack_debug_next_audio_time += dec_ctx->channels * frame->nb_samples * bytes_per_sample;
        Assert(frame->avframe->linesize[0] == audio.dec_ctx->channels * frame->avframe->nb_samples * audio.bytes_per_sample / num_actual_data_channels,
               "Smack audio size mismatch in frame %u in %s\n", audio_num_read_frames, movie_filename);

        frame->play_time = (double)frame->avpacket->pts / (double)audio.bytes_per_second;
      }
      break;

                case AV_CODEC_ID_MP3:
                {
                  static int mp3_samples_decoded_so_far = 0;
                  static int mp3_prev_samples_count = frame->avframe->nb_samples; // mp3 seems to always feed same amount of samples
                  frame->play_time = (double)mp3_samples_decoded_so_far / (double)audio.dec_ctx->sample_rate;

                  mp3_samples_decoded_so_far += frame->avframe->nb_samples;
                  Assert(mp3_prev_samples_count == frame->avframe->nb_samples,
                          "MP3 audio have variable sample count in frame %u in %s\n", audio_num_read_frames, movie_filename);
                }
                break;

                default:
                {
                  __debugbreak();
                  double samples_per_second = (double)audio.dec_ctx->time_base.den / (double)audio.dec_ctx->time_base.num;
                  double play_length = frame->avframe->nb_samples / samples_per_second;
                  frame->play_time = (double)frame->avpacket->pts / samples_per_second;
                }
                break;*/
  }

  if (!avframe->channel_layout)
  {
    log("Audio channel layout not specified, rolling back to default\n");
    avframe->channel_layout = av_get_default_channel_layout(dec_ctx->channels);
  }

  *out_num_audio_samples = dec_ctx->channels * avframe->nb_samples;
  InterleaveAudioData(out_audio_data, dec_ctx->sample_fmt,
                      dec_ctx->channels, avframe->nb_samples, avframe->data);
  return true;
}


bool LoadAudioTrack(AVFormatContext *format_ctx, AVCodecContext *dec_ctx, int audio_stream_idx, MemoryStream *out_audio_stream, int *out_num_audio_frames, int *out_num_audio_samples)
{
  out_audio_stream->Reset();

  AVFrame  *frame = avcodec_alloc_frame();
  AVPacket *packet = new AVPacket;
  av_init_packet(packet);

  int num_audio_frames = 0;
  int num_audio_samples = 0;
  while (av_read_frame(format_ctx, packet) >= 0)
  {
    if (packet->stream_index != audio_stream_idx)
    {
      //log("Suspicious stream id %u in %s", packet->stream_index, filenamea);
      continue;
    }

    int num_samples_decoded;
    DecodeAudioFrame(dec_ctx, packet, frame, out_audio_stream, &num_samples_decoded);

    num_audio_samples += num_samples_decoded;
    num_audio_frames++;
  }
  *out_num_audio_frames = num_audio_frames;
  *out_num_audio_samples = num_audio_samples;

  avcodec_free_frame(&frame);
  delete packet;

  return true;
}


class Track: public Media::ITrack
{
  public:
    inline Track()
    {
      this->format_ctx = nullptr;
      this->audio_num_samples = 0;
    }

    void Release()
    {
      ReleaseAvcodec();
    }

    void ReleaseAvcodec()
    {
      audio.Release();
      if (format_ctx)
      {
        av_close_input_file(format_ctx);
        format_ctx = nullptr;
      }
    }

    bool Load(const wchar_t *filename)
    {
      char filenamea[1024];
      sprintf(filenamea, "%S", filename);

      if (avformat_open_input(&format_ctx, filenamea, nullptr, nullptr) >= 0)
      {
        if (avformat_find_stream_info(format_ctx, nullptr) >= 0)
        {
          av_dump_format(format_ctx, 0, filenamea, 0);

          if (!av_open_audio_stream(format_ctx, &audio))
          {
            Error("Cannot open strack: %s", filenamea);
            return Release(), false;
          }
          
          MemoryStream audio_plain_data;
          int          num_audio_frames;
          int          num_audio_samples;
          if (LoadAudioTrack(format_ctx, audio.dec_ctx, audio.stream_idx, &audio_plain_data, &num_audio_frames, &num_audio_samples))
          {
            /*#ifdef _DEBUG
              char debug_filename[1024];
              sprintf(debug_filename, "%s.wav", filenamea);
              FILE *wav = fopen(debug_filename, "w+b");

              extern void write_wav_header(FILE *wav, int channel_count = 2, int sample_rate = 22050, int bytes_per_sample = 2);
              write_wav_header(wav, audio.dec_ctx->channels, audio.dec_ctx->sample_rate, audio.bytes_per_sample);

              fwrite(audio_plain_data.Ptr(), audio_plain_data.Current(), 1, wav);
            
              extern void fix_wav_header(FILE *wav, int wav_bytes_in_stream);
              fix_wav_header(wav, audio_plain_data.Current());
            #endif*/

            device_buffer = provider->CreateTrack16(audio.dec_ctx->channels, audio.dec_ctx->sample_rate, 2, num_audio_samples, audio_plain_data.Ptr());

            ReleaseAvcodec();
            return true;
          }
        }
        Release();
      }
      return false;
    }

    virtual void Play(bool loop)
    {
      provider->PlayTrack16(device_buffer, loop);
    }


  protected:
    AVFormatContext *format_ctx;
    AVAudioStream    audio;
    int              audio_num_samples;

    OpenALSoundProvider::TrackBuffer *device_buffer;
};



class Movie: public Media::IMovie
{
  public:
    inline Movie()
    {
      this->movie_filename[0] = 0;
      this->width = 0;
      this->height = 0;
      this->format_ctx = nullptr;
      this->end_of_file = false;
      this->playback_time = 0.0;

      this->num_audio_frames = 0;
      this->num_audio_samples = 0;

      this->last_resampled_frame_num = -1;
      memset(last_resampled_frame_data, 0, sizeof(last_resampled_frame_data));
      memset(last_resampled_frame_linesize, 0, sizeof(last_resampled_frame_linesize));
    }


    inline void Release()
    {
      ReleaseAVCodec();
    }

    inline void ReleaseAVCodec()
    {
      audio.Release();
      video.Release();
      if (format_ctx)
      {
        av_close_input_file(format_ctx);
        format_ctx = nullptr;
      }
    }

    bool Load(const wchar_t *filename, int dst_width, int dst_height, int cache_ms)
    {
      char filenamea[1024];
      sprintf(filenamea, "%S", filename);
      sprintf(movie_filename, "%S", filename);

      width = dst_width;
      height = dst_height;
      if (avformat_open_input(&format_ctx, filenamea, nullptr, nullptr) >= 0)
      {
        if (avformat_find_stream_info(format_ctx, nullptr) >= 0)
        {
          av_dump_format(format_ctx, 0, filenamea, 0);

          if (!av_open_audio_stream(format_ctx, &audio))
          {
            Error("Cannot open audio stream: %s", filenamea);
            return Release(), false;
          }
          
          if (!av_open_video_stream(format_ctx, &video))
          {
            Error("Cannot open video stream: %s", filenamea);
            return Release(), false;
          }
          
          decoding_packet = new AVPacket;
          av_init_packet(decoding_packet);
      
          decoding_frame = avcodec_alloc_frame();

          audio_data_in_device = provider->CreateStreamingTrack16(audio.dec_ctx->channels, audio.dec_ctx->sample_rate, 2);

          return true;
        }
      }
      return false;
    }

    virtual void Play()
    {
    }

    virtual void GetNextFrame(double dt, void *dst_surface)
    {
      playback_time += dt;

      AVPacket *avpacket = decoding_packet;
      AVFrame *avframe = decoding_frame;
      avcodec_get_frame_defaults(avframe);

      int desired_frame_number = floor(playback_time * video.dec_ctx->time_base.den / video.dec_ctx->time_base.num + 0.5);
      if (last_resampled_frame_num == desired_frame_number)
      {
        memcpy(dst_surface, last_resampled_frame_data[0], height * last_resampled_frame_linesize[0]);
        return;
      }

      volatile int decoded = false;
      do
      {
        if (av_read_frame(format_ctx, avpacket) < 0)
        {
          // probably movie is finished
          __debugbreak();
        }

        // audio packet - queue into playing
        if (avpacket->stream_index == audio.stream_idx)
        {
          MemoryStream audio_data;
          if (DecodeAudioFrame(audio.dec_ctx, avpacket, avframe, &audio_data, &num_audio_samples))
            provider->Stream16(audio_data_in_device, num_audio_samples, audio_data.Ptr());
        }
        // video packet - decode & maybe show
        else if (avpacket->stream_index == video.stream_idx)
        {
          do
          {
            if (avcodec_decode_video2(video.dec_ctx, avframe, (int *)&decoded, avpacket) < 0)
              __debugbreak();
          } while (!decoded);
        }

      } while (avpacket->stream_index != video.stream_idx ||
               avpacket->pts != desired_frame_number);

      if (decoded)
      {
        if (last_resampled_frame_data[0])
          av_freep(&last_resampled_frame_data[0]);

        AVPixelFormat  rescaled_format = AV_PIX_FMT_RGB32;
        uint8_t       *rescaled_data[4] = {nullptr, nullptr, nullptr, nullptr};
        int            rescaled_linesize[4] = {0, 0, 0, 0};
        if (av_image_alloc(rescaled_data, rescaled_linesize, width, height, rescaled_format, 1) >= 0)
        {
          SwsContext *converter = sws_getContext(avframe->width, avframe->height, (AVPixelFormat)avframe->format,
                                                 width, height, rescaled_format,
                                                 SWS_BICUBIC, nullptr, nullptr, nullptr);
          sws_scale(converter, avframe->data, avframe->linesize, 0, avframe->height, rescaled_data, rescaled_linesize);
          sws_freeContext(converter);

          memcpy(dst_surface, rescaled_data[0], height * rescaled_linesize[0]);

          last_resampled_frame_num = desired_frame_number;
          memcpy(last_resampled_frame_data, rescaled_data, sizeof(rescaled_data));
          memcpy(last_resampled_frame_linesize, rescaled_linesize, sizeof(rescaled_linesize));
        }
      }
      else
        memset(dst_surface, 0, width * height * 4);
    }

  protected:
    char             movie_filename[256];
    int              width;
    int              height;
    AVFormatContext *format_ctx;
    double           playback_time;
    bool             end_of_file;

    AVPacket        *decoding_packet;
    AVFrame         *decoding_frame;

    AVAudioStream   audio;
    int             num_audio_frames;
    int             num_audio_samples;
    OpenALSoundProvider::StreamingTrackBuffer *audio_data_in_device;

    AVVideoStream   video;
    int             last_resampled_frame_num;
    uint8_t        *last_resampled_frame_data[4];
    int             last_resampled_frame_linesize[4];
};


ITrack *Player::LoadTrack(const wchar_t *filename)
{
  auto track = new Track;
  if (!track->Load(filename))
  {
    delete track;
    track = nullptr;
  }
  return track;
}


IMovie *Player::LoadMovie(const wchar_t *filename, int width, int height, int cache_ms)
{
  auto movie = new Movie;
  if (!movie->Load(filename, width, height, cache_ms))
  {
    delete movie;
    movie = nullptr;
  }
  return movie;
}






void av_logger(void *, int, const char *format, va_list args)
{
  va_list va;
  va_start(va, format);
  char msg[256];
  vsprintf(msg, format, va);
  va_end(va);

  log("av: %s", msg);
}

Player::Player()
{
  static int libavcodec_initialized = false;

  if (!libavcodec_initialized)
  {
    av_log_set_callback(av_logger);
    avcodec_register_all();
    av_register_all();

    libavcodec_initialized = true;
  }

  if (!provider)
  {
    provider = new OpenALSoundProvider;
    provider->Initialize();
  }
}

Player::~Player()
{
}