// FFmpegDecoder.cpp
#include "FFmpegDecoder.h"

FFmpegDecoder::FFmpegDecoder(QObject* parent) :
    QThread(parent),
    videoLabel(nullptr),
    abort(false),
    restart(false),
    formatContext(nullptr),
    codecContext(nullptr),
    frame(nullptr),
    packet(nullptr),
    swsContext(nullptr),
    videoStreamIndex(-1)            // 初始化成员变量
{
    av_log_set_level(AV_LOG_QUIET); // 设置日志级别为安静模式
    avformat_network_init();        // 初始化网络
}

FFmpegDecoder::~FFmpegDecoder()
{
    mutex.lock();
    abort = true;
    condition.wakeOne();
    mutex.unlock();
    wait();
    if (codecContext) {
        avcodec_free_context(&codecContext);
    }
    if (frame) {
        av_frame_free(&frame);
    }
    if (packet) {
        av_packet_free(&packet);
    }
    if (swsContext) {
        sws_freeContext(swsContext);
    }
    if (formatContext) {
        avformat_close_input(&formatContext);
    }
    avformat_network_deinit(); // 反初始化网络
}

void FFmpegDecoder::initialize()
{
    // 初始化FFmpeg库
    avformat_network_init();
}

void FFmpegDecoder::decodeFile(const QString& filePath, QLabel* videoLabel)
{
    QMutexLocker locker(&mutex);
    this->filePath = filePath;
    this->videoLabel = videoLabel;
    if (!isRunning()) {
        //start(LowPriority); 
        start(NormalPriority);
    }
    restart = true;
    condition.wakeOne();
}

void FFmpegDecoder::run()
{
    QFile file(filePath);
    qint64 fileSize = 0;

    for (;;) {
        mutex.lock();
        while (!restart && !abort) {
            condition.wait(&mutex);
        }
        if (abort) {
            mutex.unlock();
            break;
        }
        restart = false;
        QLabel* currentVideoLabel = videoLabel;
        QSize labelSize = currentVideoLabel->size();
        mutex.unlock();
        qDebug() << "Video label size: Width =" << labelSize.width() << ", Height =" << labelSize.height();

        if (!file.open(QIODevice::ReadOnly)) {
            qWarning() << "Failed to open file:" << filePath;
            continue;
        }
        // 从上次处理的位置开始读取
        file.seek(fileSize); 

        formatContext = nullptr;
        codecContext = nullptr;
        frame = nullptr;
        packet = nullptr;

        // 通过 FFmpeg 初始化格式上下文和解码器
        if (avformat_open_input(&formatContext, filePath.toStdString().c_str(), nullptr, nullptr) != 0) {
            qWarning() << "Failed to open file with FFmpeg:" << filePath;
            file.close();
            continue;
        }

        if (avformat_find_stream_info(formatContext, nullptr) < 0) {
            qWarning() << "Failed to retrieve stream info";
            avformat_close_input(&formatContext);
            file.close();
            continue;
        }

        videoStreamIndex = -1;
        for (unsigned int i = 0; i < formatContext->nb_streams; ++i) {
            if (formatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
                videoStreamIndex = i;
                break;
            }
        }
        if (videoStreamIndex == -1) {
            qWarning() << "No video stream found";
            avformat_close_input(&formatContext);
            file.close();
            continue;
        }

        AVCodecParameters* codecParameters = formatContext->streams[videoStreamIndex]->codecpar;
        const AVCodec* codec = avcodec_find_decoder(codecParameters->codec_id);
        if (!codec) {
            qWarning() << "Unsupported codec";
            avformat_close_input(&formatContext);
            file.close();
            continue;
        }

        codecContext = avcodec_alloc_context3(codec);
        if (!codecContext) {
            qWarning() << "Failed to allocate codec context";
            avformat_close_input(&formatContext);
            file.close();
            continue;
        }

        if (avcodec_parameters_to_context(codecContext, codecParameters) < 0) {
            qWarning() << "Failed to copy codec parameters to context";
            avcodec_free_context(&codecContext);
            avformat_close_input(&formatContext);
            file.close();
            continue;
        }

        if (avcodec_open2(codecContext, codec, nullptr) < 0) {
            qWarning() << "Failed to open codec";
            avcodec_free_context(&codecContext);
            avformat_close_input(&formatContext);
            file.close();
            continue;
        }

        frame = av_frame_alloc();
        packet = av_packet_alloc();

        // 主解码循环
        while (!abort) {
            qint64 currentFileSize = file.size();
            if (currentFileSize > fileSize) {
                fileSize = currentFileSize;
                file.seek(fileSize); // 设置文件读取位置到末尾

                // 读取并处理数据包
                while (av_read_frame(formatContext, packet) >= 0) {
                    if (packet->stream_index == videoStreamIndex) {
                        int ret = avcodec_send_packet(codecContext, packet);
                        if (ret < 0) {
                            qWarning() << "Error sending packet for decoding";
                            av_packet_unref(packet);
                            continue;
                        }
                        while (ret >= 0) {
                            ret = avcodec_receive_frame(codecContext, frame);
                            if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
                                qWarning() << "----------- break";
                                av_packet_unref(packet);
                                continue;
                                //break;
                            }
                            else if (ret < 0) {
                                qWarning() << "Error during decoding";
                                break;
                            }

                            /*mutex.lock();
                            QSize labelSize = currentVideoLabel->size();
                            mutex.unlock();*/
                            //qDebug() << "Video label size: Width =" << labelSize.width() << ", Height =" << labelSize.height();
                            QImage img = avFrameToQImage(frame);
                            QImage scaledImage = img.scaled(labelSize, Qt::KeepAspectRatio, Qt::SmoothTransformation);
                            currentVideoLabel->setPixmap(QPixmap::fromImage(scaledImage));
                            //currentVideoLabel->setPixmap(QPixmap::fromImage(img));
                            QThread::msleep(10);  // Simulate 25 FPS frame rate
                        }
                    }
                    av_packet_unref(packet);
                }
            }

            mutex.lock();
            if (restart) {
                restart = false;
                mutex.unlock();
                break;
            }
            mutex.unlock();
        }

        avcodec_free_context(&codecContext);
        avformat_close_input(&formatContext);
        av_frame_free(&frame);
        av_packet_free(&packet);
        file.close();
        sws_freeContext(swsContext);

        mutex.lock();
        if (!restart) {
            condition.wait(&mutex);
        }
        mutex.unlock();
    }
}


QImage FFmpegDecoder::avFrameToQImage(AVFrame* frame)
{
    int width = frame->width;
    int height = frame->height;
    AVPixelFormat pixFmt = (AVPixelFormat)frame->format;

    SwsContext* swsCtx = sws_getContext(width, height, pixFmt, width, height, AV_PIX_FMT_RGB24, SWS_BILINEAR, nullptr, nullptr, nullptr);
    if (!swsCtx) {
        qWarning() << "Failed to initialize the conversion context";
        return QImage();
    }

    QImage img(width, height, QImage::Format_RGB888);
    uint8_t* dest[4] = { img.bits(), nullptr, nullptr, nullptr };
    int destLinesize[4] = { img.bytesPerLine(), 0, 0, 0 };

    sws_scale(swsCtx, frame->data, frame->linesize, 0, height, dest, destLinesize);
    sws_freeContext(swsCtx);

    return img;
}