//指定文件的编码为UTF-8
#pragma execution_character_set("utf-8")

#include "ReverseDecodThread.h"

ReverseDecodThread::ReverseDecodThread()
{
    qDebug() << "FFMPEG版本信息:" << av_version_info();
}

ReverseDecodThread::~ReverseDecodThread()
{

}


/*
功能: 设置媒体文件
*/
int ReverseDecodThread::set_VideoFile(QString media)
{
    //打开媒体文件
    QByteArray array=media.toUtf8();
    strncpy(m_MediaFile, array.data(), sizeof(m_MediaFile));
    m_run = 1;
    return 1;
}


void ReverseDecodThread::SetSate(int run)
{
	m_run = run;
}

int ReverseDecodThread::GetSate()
{
	return m_run;
}


//跳转视频帧
void ReverseDecodThread::SetSeekPos(qint64 pos)
{
	is_CurrentSeekPos = 1;
    m_n64CurrentSeekPos = pos;
    m_run=1;  //运行状态

    //获取系统本地时间
    play_base_time=QDateTime::currentMSecsSinceEpoch();
}


void ReverseDecodThread::PausePlay()
{
	m_run = 2;
}

void ReverseDecodThread::StopPlay()
{
	m_run = 0;
}

void ReverseDecodThread::LogSend(QString text)
{
	//qDebug() << text;
}


//线程执行起点
void ReverseDecodThread::run()
{
    LogSend("开始播放视频.\n");
    StartPlay();
}


//播放视频
int ReverseDecodThread::StartPlay()
{
    format_ctx = avformat_alloc_context();
    if (!format_ctx) {
        LogSend(tr("初始化失败 无法打开视频文件: %1").arg(m_MediaFile));
        return -1;
    }
    //1.打开多媒体流,并且获取一些信息
    if(avformat_open_input(&format_ctx, m_MediaFile, nullptr, nullptr) != 0)
    {
         LogSend(tr("无法打开视频文件: %1").arg(m_MediaFile));
         return -1;
    }

    //2. 读取媒体文件的数据包以获取流信息
    if(avformat_find_stream_info(format_ctx, nullptr) < 0)
    {
        LogSend(tr("无法获取流信息.\n"));
        return -1;
    }
//    context = avcodec_alloc_context3(codec)

    AVCodecContext* avctx = avcodec_alloc_context3(NULL);
    if (nullptr == avctx) {
        return -1;
    }

    st_index[AVMEDIA_TYPE_VIDEO] = av_find_best_stream(format_ctx, AVMEDIA_TYPE_VIDEO, st_index[AVMEDIA_TYPE_VIDEO], -1, NULL, 0);
    st_index[AVMEDIA_TYPE_AUDIO] = av_find_best_stream(format_ctx, AVMEDIA_TYPE_AUDIO,
        st_index[AVMEDIA_TYPE_AUDIO],
        st_index[AVMEDIA_TYPE_VIDEO],
        NULL, 0);

    //3.打印视频的信息
    LogSend(tr("视频中流的数量: %1\n").arg(format_ctx->nb_streams));
    for(int i = 0; i < format_ctx->nb_streams; ++i)
    {
        const AVStream* stream = format_ctx->streams[i];
        
        if(stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
        {
            int ret = avcodec_parameters_to_context(avctx, stream->codecpar);
            if (ret < 0) {
                return -1;
            }
            //查找解码器
            const AVCodec *video_pCodec=avcodec_find_decoder(avctx->codec_id);
            //打开解码器
            if(avcodec_open2(avctx, video_pCodec,nullptr)!=0)
            {
                  LogSend(tr("解码器打开失败.\n"));
                  return -1;
            }
            video_stream_index = i;
            bool flag = false;
            if (video_width != stream->codecpar->width) {
                video_width = stream->codecpar->width;
                flag = true;
            }

            if (video_height != stream->codecpar->height) {
                video_height = stream->codecpar->height;
                flag = true;
            }

            if (flag) {
                emit VideoSizeChanged(video_width, video_height);
            }
            

            LogSend(tr("视频帧的尺寸(以像素为单位): (宽X高)%1x%2 像素格式: %3\n").arg(
                stream->codecpar->width).arg(stream->codecpar->height).arg(stream->codecpar->format));
        }
    }

    if (video_stream_index == -1)
    {
         LogSend("没有检测到视频流.\n");
         return -1;
    }

    AVRational frameRate = format_ctx->streams[video_stream_index]->avg_frame_rate;

    /*设置视频转码器*/
    SRC_VIDEO_pFrame = av_frame_alloc();
    RGB24_pFrame = av_frame_alloc();// 存放解码后YUV数据的缓冲区

    //将解码后的YUV数据转换成RGB24
    img_convert_ctx = sws_getContext(video_width, video_height,
        avctx->pix_fmt,video_width, video_height,
        AV_PIX_FMT_RGBA, SWS_BICUBIC, nullptr, nullptr, nullptr);

    //计算RGB图像所占字节大小
    int numBytes= av_image_get_buffer_size(AV_PIX_FMT_RGBA,video_width,video_height, 1);

    //申请空间存放RGB图像数据
    out_buffer_rgb = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));

    // avpicture_fill函数将ptr指向的数据填充到picture内,但并没有拷贝,只是将picture结构内的data指针指向了ptr的数据
    /*avpicture_fill((AVPicture *) RGB24_pFrame, out_buffer_rgb, AV_PIX_FMT_RGB24,
            video_width, video_height);*/
    av_image_fill_arrays(RGB24_pFrame->data, RGB24_pFrame->linesize, out_buffer_rgb, AV_PIX_FMT_RGBA,
        video_width, video_height, 1);

    qDebug()<<"format_ctx->duration:"<<format_ctx->duration;

    //获取系统本地时间
    play_base_time=QDateTime::currentMSecsSinceEpoch();
   // m_run = 1;
    //表示视频加载成功
    while(m_run)
    {
        if(m_run == 2)
        {
            msleep(100); //暂停播放
			continue;
        }

		if (is_CurrentSeekPos)
		{
			is_CurrentSeekPos = 0;
            //偏移到指定位置再开始解码    AVSEEK_FLAG_BACKWARD 向后找最近的关键帧
            av_seek_frame(format_ctx, -1, m_n64CurrentSeekPos* AV_TIME_BASE, AVSEEK_FLAG_BACKWARD);
            qDebug()<<"跳转的位置:"<<m_n64CurrentSeekPos;
		}

        double video_clock;
        AVPacket pkt;

        //1. 读取一帧数据
        if(av_read_frame(format_ctx, &pkt) < 0)
        {
            m_run=2; //设置为暂停状态
          //  qDebug()<<"数据读取完毕.";
            continue;
        }

        if(pkt.stream_index == video_stream_index)
        {
            //当前时间
           video_clock = av_q2d(format_ctx->streams[video_stream_index]->time_base) * pkt.pts;

       //    qDebug()<<"pkt.pts:"<<pkt.pts<<"video_clock:"<<video_clock;


           //解码视频 frame
           //2. 发送视频帧
            if (avcodec_send_packet(avctx,&pkt) != 0)
            {
                av_packet_unref(&pkt);//不成功就释放这个pkt
                continue;
            }

            //3. 接受后对视频帧进行解码
            if (avcodec_receive_frame(avctx, SRC_VIDEO_pFrame) != 0)
            {
                av_packet_unref(&pkt);//不成功就释放这个pkt
                continue;
            }

            //4. 转格式
           sws_scale(img_convert_ctx,
                   (uint8_t const **) SRC_VIDEO_pFrame->data,
                   SRC_VIDEO_pFrame->linesize, 0, video_height, RGB24_pFrame->data,
                   RGB24_pFrame->linesize);


    
           //5. 加载图片数据
           QImage image(out_buffer_rgb,video_width,video_height,QImage::Format_RGBA8888);

           //通知界面更新
           VideoDataOutput(image.copy());

           //时间信号
           sig_getCurrentTime(video_clock, format_ctx->duration *1.0 / AV_TIME_BASE);

           QThread::msleep(40);
        }
               //释放包
           av_packet_unref(&pkt);

    }

    LogSend("视频音频解码播放器的线程退出成功.\n");

    if(SRC_VIDEO_pFrame) av_frame_free(&SRC_VIDEO_pFrame);
    if(RGB24_pFrame) av_frame_free(&RGB24_pFrame);
    if(img_convert_ctx)sws_freeContext(img_convert_ctx);
    if(out_buffer_rgb)av_free(out_buffer_rgb);

    SRC_VIDEO_pFrame=nullptr;
    RGB24_pFrame=nullptr;
    img_convert_ctx=nullptr;
    out_buffer_rgb=nullptr;

    if(format_ctx)
    {
        avcodec_free_context(&avctx);
        avformat_close_input(&format_ctx);//释放解封装器的空间，以防空间被快速消耗完
        avformat_free_context(format_ctx);
    }

    return 0;
}