#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <stdarg.h>

#include "libavformat/avformat.h"

static AVFormatContext* g_pContainer;

static AVOutputFormat* g_pFormat;

static AVStream* g_pAStream;

static AVStream* g_pVStream;

static AVFrame* g_pAFrame;

static AVFrame* g_pVFrame;

static AVCodec* g_pACodec;

static AVCodec* g_pVCodec;

static AVCodecContext* g_pAudio;

static AVCodecContext* g_pVideo;

static int g_Width, g_Height;

static int g_Frequency, g_Channels;

static int g_VQuality, g_AQuality;

static AVRational g_Framerate;

static const char* g_pPreset;

static FILE* g_pSoundFile;

static int16_t* g_pSamples;

static int g_NumSamples;

/*

Initially I wrote code for latest ffmpeg, but on Linux (Ubuntu)

only older version is available from repository. That's why you see here

all of this #if LIBAVCODEC_VERSION_MAJOR < 54.

Actually, it may be possible to remove code for newer version

and use only code for older version.

*/

#if LIBAVCODEC_VERSION_MAJOR < 54

#define OUTBUFFER_SIZE 200000

static uint8_t g_OutBuffer[OUTBUFFER_SIZE];

#endif

// pointer to function from hwengine (uUtils.pas)

static void (*AddFileLogRaw)(const char* pString);

static void FatalError(const char* pFmt, ...)

{

    const char Buffer[1024];

    va_list VaArgs;

    va_start(VaArgs, pFmt);

    vsnprintf(Buffer, 1024, pFmt, VaArgs);

    va_end(VaArgs);

    AddFileLogRaw("Error in av-wrapper: ");

    AddFileLogRaw(Buffer);

    AddFileLogRaw("\n");

    exit(1);

}

// Function to be called from libav for logging.

// Note: libav can call LogCallback from different threads

// (there is mutex in AddFileLogRaw).

static void LogCallback(void* p, int Level, const char* pFmt, va_list VaArgs)

{

    const char Buffer[1024];

    vsnprintf(Buffer, 1024, pFmt, VaArgs);

    AddFileLogRaw(Buffer);

}

static void Log(const char* pFmt, ...)

{

    const char Buffer[1024];

    va_list VaArgs;

    va_start(VaArgs, pFmt);

    vsnprintf(Buffer, 1024, pFmt, VaArgs);

    va_end(VaArgs);

    AddFileLogRaw(Buffer);

}

static void AddAudioStream()

{

    g_pAStream = avformat_new_stream(g_pContainer, g_pACodec);

#else

    g_pAStream = av_new_stream(g_pContainer, 1);

#endif

    if(!g_pAStream)

        FatalError("Could not allocate audio stream");

    g_pAStream->id = 1;

    g_pAudio = g_pAStream->codec;

    avcodec_get_context_defaults3(g_pAudio, g_pACodec);

    g_pAudio->codec_id = g_pACodec->id;

    // put parameters

    g_pAudio->sample_fmt = AV_SAMPLE_FMT_S16;

    g_pAudio->sample_rate = g_Frequency;

    g_pAudio->channels = g_Channels;

    // set quality

    if (g_AQuality > 100)

        g_pAudio->bit_rate = g_AQuality;

    else

    {

        g_pAudio->flags |= CODEC_FLAG_QSCALE;

        g_pAudio->global_quality = g_AQuality*FF_QP2LAMBDA;

    }

    // some formats want stream headers to be separate

    if (g_pFormat->flags & AVFMT_GLOBALHEADER)

        g_pAudio->flags |= CODEC_FLAG_GLOBAL_HEADER;

    // open it

    if (avcodec_open2(g_pAudio, g_pACodec, NULL) < 0)

        FatalError("Could not open audio codec %s", g_pACodec->long_name);

#if LIBAVCODEC_VERSION_MAJOR >= 54

    if (g_pACodec->capabilities & CODEC_CAP_VARIABLE_FRAME_SIZE)

#else

    if (g_pAudio->frame_size == 0)

#endif

        g_NumSamples = 4096;

    else

        g_NumSamples = g_pAudio->frame_size;

    g_pSamples = (int16_t*)av_malloc(g_NumSamples*g_Channels*sizeof(int16_t));

    g_pAFrame = avcodec_alloc_frame();

    if (!g_pAFrame)

        FatalError("Could not allocate frame");

}

// returns non-zero if there is more sound

static int WriteAudioFrame()

{

    if (!g_pAStream)

        return 0;

    AVPacket Packet = { 0 };

    av_init_packet(&Packet);

    int NumSamples = fread(g_pSamples, 2*g_Channels, g_NumSamples, g_pSoundFile);

#if LIBAVCODEC_VERSION_MAJOR >= 54

    AVFrame* pFrame = NULL;

    if (NumSamples > 0)

    {

        g_pAFrame->nb_samples = NumSamples;

        avcodec_fill_audio_frame(g_pAFrame, g_Channels, AV_SAMPLE_FMT_S16,

                                 (uint8_t*)g_pSamples, NumSamples*2*g_Channels, 1);

        pFrame = g_pAFrame;

    }

    // when NumSamples == 0 we still need to call encode_audio2 to flush

    int got_packet;

    if (avcodec_encode_audio2(g_pAudio, &Packet, pFrame, &got_packet) != 0)

        FatalError("avcodec_encode_audio2 failed");

    if (!got_packet)

        return 0;

#else

    if (NumSamples == 0)

        return 0;

    int BufferSize = OUTBUFFER_SIZE;

    if (g_pAudio->frame_size == 0)

        BufferSize = NumSamples*g_Channels*2;

    Packet.size = avcodec_encode_audio(g_pAudio, g_OutBuffer, BufferSize, g_pSamples);

    if (Packet.size == 0)

        return 1;

    if (g_pAudio->coded_frame && g_pAudio->coded_frame->pts != AV_NOPTS_VALUE)

        Packet.pts = av_rescale_q(g_pAudio->coded_frame->pts, g_pAudio->time_base, g_pAStream->time_base);

    Packet.flags |= AV_PKT_FLAG_KEY;

    Packet.data = g_OutBuffer;

#endif

    // Write the compressed frame to the media file.

    Packet.stream_index = g_pAStream->index;

    if (av_interleaved_write_frame(g_pContainer, &Packet) != 0) 

        FatalError("Error while writing audio frame");

    return 1;

}

// add a video output stream

static void AddVideoStream()

{

    g_pVStream = avformat_new_stream(g_pContainer, g_pVCodec);

#else

    g_pVStream = av_new_stream(g_pContainer, 0);

#endif

    if (!g_pVStream)

        FatalError("Could not allocate video stream");

    g_pVideo = g_pVStream->codec;

    avcodec_get_context_defaults3(g_pVideo, g_pVCodec);

    g_pVideo->codec_id = g_pVCodec->id;

    // put parameters

    // resolution must be a multiple of two

    g_pVideo->width = g_Width;

    g_pVideo->height = g_Height;

    /* time base: this is the fundamental unit of time (in seconds) in terms

       of which frame timestamps are represented. for fixed-fps content,

       timebase should be 1/framerate and timestamp increments should be

       identically 1. */

    g_pVideo->time_base.den = g_Framerate.num;

    g_pVideo->time_base.num = g_Framerate.den;

    //g_pVideo->gop_size = 12; /* emit one intra frame every twelve frames at most */

    g_pVideo->pix_fmt = PIX_FMT_YUV420P;

    // set quality

    if (g_VQuality > 100)

        g_pVideo->bit_rate = g_VQuality;

    else

    {

        g_pVideo->flags |= CODEC_FLAG_QSCALE;

        g_pVideo->global_quality = g_VQuality*FF_QP2LAMBDA;

    }

    AVDictionary* pDict = NULL;

    if (strcmp(g_pVCodec->name, "libx264") == 0)

        av_dict_set(&pDict, "preset", g_pPreset, 0);

    // some formats want stream headers to be separate

    if (g_pFormat->flags & AVFMT_GLOBALHEADER)

        g_pVideo->flags |= CODEC_FLAG_GLOBAL_HEADER;

    // open the codec

    if (avcodec_open2(g_pVideo, g_pVCodec, &pDict) < 0)

        FatalError("Could not open video codec %s", g_pVCodec->long_name);

    g_pVFrame = avcodec_alloc_frame();

    if (!g_pVFrame)

        FatalError("Could not allocate frame");

    g_pVFrame->linesize[0] = g_Width;

    g_pVFrame->linesize[1] = g_Width/2;

    g_pVFrame->linesize[2] = g_Width/2;

    g_pVFrame->linesize[3] = 0;

}

static int WriteFrame( AVFrame* pFrame )

{

    double AudioTime, VideoTime;

    // write interleaved audio frame

    if (g_pAStream)

    {

        VideoTime = (double)g_pVStream->pts.val*g_pVStream->time_base.num/g_pVStream->time_base.den;

        do

            AudioTime = (double)g_pAStream->pts.val*g_pAStream->time_base.num/g_pAStream->time_base.den;

        while (AudioTime < VideoTime && WriteAudioFrame());

    }

    if (!g_pVStream)

        return 0;

    AVPacket Packet;

    av_init_packet(&Packet);

    Packet.data = NULL;

    Packet.size = 0;

    g_pVFrame->pts++;

    if (g_pFormat->flags & AVFMT_RAWPICTURE)

    {

        /* raw video case. The API will change slightly in the near

           future for that. */

        Packet.flags |= AV_PKT_FLAG_KEY;

        Packet.stream_index = g_pVStream->index;

        Packet.data = (uint8_t*)pFrame;

        Packet.size = sizeof(AVPicture);

        if (av_interleaved_write_frame(g_pContainer, &Packet) != 0)

            FatalError("Error while writing video frame");

        return 0;

    }

    else

    {

#if LIBAVCODEC_VERSION_MAJOR >= 54

        int got_packet;

        if (avcodec_encode_video2(g_pVideo, &Packet, pFrame, &got_packet) < 0)

            FatalError("avcodec_encode_video2 failed");

        if (!got_packet)

            return 0;

        if (Packet.pts != AV_NOPTS_VALUE)

            Packet.pts = av_rescale_q(Packet.pts, g_pVideo->time_base, g_pVStream->time_base);

        if (Packet.dts != AV_NOPTS_VALUE)

            Packet.dts = av_rescale_q(Packet.dts, g_pVideo->time_base, g_pVStream->time_base);

#else 

        Packet.size = avcodec_encode_video(g_pVideo, g_OutBuffer, OUTBUFFER_SIZE, pFrame);

        if (Packet.size < 0)

            FatalError("avcodec_encode_video failed");

        if (Packet.size == 0)

            return 0;

        if( g_pVideo->coded_frame->pts != AV_NOPTS_VALUE)

            Packet.pts = av_rescale_q(g_pVideo->coded_frame->pts, g_pVideo->time_base, g_pVStream->time_base);

        if( g_pVideo->coded_frame->key_frame )

            Packet.flags |= AV_PKT_FLAG_KEY;

        Packet.data = g_OutBuffer;

#endif

        // write the compressed frame in the media file

        Packet.stream_index = g_pVStream->index;

        if (av_interleaved_write_frame(g_pContainer, &Packet) != 0)

            FatalError("Error while writing video frame");

        return 1;

    }

}

void AVWrapper_WriteFrame(uint8_t* pY, uint8_t* pCb, uint8_t* pCr)

{

    g_pVFrame->data[0] = pY;

    g_pVFrame->data[1] = pCb;

    g_pVFrame->data[2] = pCr;

    WriteFrame(g_pVFrame);

}

void AVWrapper_Init(

         void (*pAddFileLogRaw)(const char*),

         const char* pFilename,

         const char* pSoundFile,

         const char* pFormatName,

         const char* pVCodecName,

         const char* pACodecName,

         const char* pVPreset,

         int Width, int Height,

         int FramerateNum, int FramerateDen,

         int Frequency, int Channels,

         int VQuality, int AQuality)

{    

    AddFileLogRaw = pAddFileLogRaw;

    av_log_set_callback( &LogCallback );

    g_Width = Width;

    g_Height = Height;

    g_Framerate.num = FramerateNum;

    g_Framerate.den = FramerateDen;

    g_Frequency = Frequency;

    g_Channels = Channels;

    g_VQuality = VQuality;

    g_AQuality = AQuality;

    g_pPreset = pVPreset;

    // initialize libav and register all codecs and formats

    av_register_all();

    // find format

    g_pFormat = av_guess_format(pFormatName, NULL, NULL);

    if (!g_pFormat)

        FatalError("Format \"%s\" was not found", pFormatName);

    // allocate the output media context

    g_pContainer = avformat_alloc_context();

    if (!g_pContainer)

        FatalError("Could not allocate output context");

    g_pContainer->oformat = g_pFormat;

    // append extesnion to filename

    // find codecs

    g_pVCodec = avcodec_find_encoder_by_name(pVCodecName);

    g_pACodec = avcodec_find_encoder_by_name(pACodecName);

    // add audio and video stream to container

    g_pVStream = NULL;

    g_pAStream = NULL;

    if (g_pVCodec)

        AddVideoStream();

    else

        Log("Video codec \"%s\" was not found; video will be ignored.\n", pVCodecName);

    if (g_pACodec)

        AddAudioStream();

    else

        Log("Audio codec \"%s\" was not found; audio will be ignored.\n", pACodecName);

    if (!g_pAStream && !g_pVStream)

        FatalError("No video, no audio, aborting...");

    if (g_pAStream)

    {

        g_pSoundFile = fopen(pSoundFile, "rb");

        if (!g_pSoundFile)

            FatalError("Could not open %s", pSoundFile);

    }

    // write format info to log

    av_dump_format(g_pContainer, 0, g_pContainer->filename, 1);

    // open the output file, if needed

    if (!(g_pFormat->flags & AVFMT_NOFILE))

    {

        if (avio_open(&g_pContainer->pb, g_pContainer->filename, AVIO_FLAG_WRITE) < 0)

            FatalError("Could not open output file (%s)", pFilename);

    }

    // write the stream header, if any

    avformat_write_header(g_pContainer, NULL);

    g_pVFrame->pts = -1;

}

void AVWrapper_Close()

{

    // output buffered frames

    if (g_pVCodec->capabilities & CODEC_CAP_DELAY)

        while( WriteFrame(NULL) );

    // output any remaining audio

    while( WriteAudioFrame() );

    // write the trailer, if any.

    av_write_trailer(g_pContainer);

    // close the output file

    if (!(g_pFormat->flags & AVFMT_NOFILE))

        avio_close(g_pContainer->pb);

    // free everything

    if (g_pVStream)

    {

        avcodec_close(g_pVideo);

        av_free(g_pVideo);

        av_free(g_pVStream);

        av_free(g_pVFrame);

    }

    if (g_pAStream)

    {

        avcodec_close(g_pAudio);

        av_free(g_pAudio);

        av_free(g_pAStream);

        av_free(g_pAFrame);

        av_free(g_pSamples);

        fclose(g_pSoundFile);

    }

    av_free(g_pContainer);

}