#include "ffmpegvideopuller.h"

#include <QDebug>
#include <chrono>
#include <thread>

FFmpegVideoPuller::FFmpegVideoPuller(QObject* parent)
    : QObject(parent)
{
    // av_register_all();
    avformat_network_init();
}

FFmpegVideoPuller::~FFmpegVideoPuller()
{
    stop();
}

bool FFmpegVideoPuller::open(const QString& url, int videoBufferSec, int audioBufferSec)
{
    m_url = url;
    // 打开流
    if (avformat_open_input(&m_fmtCtx, url.toStdString().c_str(), nullptr, nullptr) < 0)
        return false;
    if (avformat_find_stream_info(m_fmtCtx, nullptr) < 0)
        return false;

    // 查找视频流
    for (unsigned i = 0; i < m_fmtCtx->nb_streams; ++i) {
        if (m_fmtCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO
            && m_videoStreamIdx == -1) {
            m_videoStreamIdx = i;
        }
        if (m_fmtCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO
            && m_audioStreamIdx == -1) {
            m_audioStreamIdx = i;
        }
    }
    if (m_videoStreamIdx == -1)
        return false;

    // 打开视频解码器
    const AVCodec* vcodec = avcodec_find_decoder(
        m_fmtCtx->streams[m_videoStreamIdx]->codecpar->codec_id);
    m_videoCodecCtx = avcodec_alloc_context3(vcodec);
    avcodec_parameters_to_context(m_videoCodecCtx, m_fmtCtx->streams[m_videoStreamIdx]->codecpar);
    avcodec_open2(m_videoCodecCtx, vcodec, nullptr);

    // 打开音频解码器
    if (m_audioStreamIdx != -1) {
        const AVCodec* acodec = avcodec_find_decoder(
            m_fmtCtx->streams[m_audioStreamIdx]->codecpar->codec_id);
        m_audioCodecCtx = avcodec_alloc_context3(acodec);
        avcodec_parameters_to_context(m_audioCodecCtx,
                                      m_fmtCtx->streams[m_audioStreamIdx]->codecpar);
        avcodec_open2(m_audioCodecCtx, acodec, nullptr);
    }

    // 计算缓冲区大小
    int videoFps = 25;
    AVRational fr = m_fmtCtx->streams[m_videoStreamIdx]->avg_frame_rate;
    if (fr.num && fr.den)
        videoFps = int(av_q2d(fr));
    int videoBufferSize = videoBufferSec * videoFps;
    int audioBufferSize = audioBufferSec * 50; // 假设每秒50帧

    // 创建缓冲区
    m_videoBuffer = new RingBuffer<AVFrame*>(videoBufferSize);
    m_audioBuffer = new RingBuffer<AVFrame*>(audioBufferSize);
    m_videoBuffer->setDeleter([](AVFrame*& f) { av_frame_free(&f); });
    m_audioBuffer->setDeleter([](AVFrame*& f) { av_frame_free(&f); });

    m_videoPlayIndex = 0;
    m_audioPlayIndex = 0;
    m_currentPts = 0.0;

    // 获取总时长
    if (m_fmtCtx->duration > 0) {
        m_totalDuration = m_fmtCtx->duration / (double)AV_TIME_BASE;
    } else {
        m_totalDuration = -1.0;
    }

    return true;
}

void FFmpegVideoPuller::setSpeed(float speed)
{
    std::lock_guard<std::mutex> lock(m_speedMutex);
    m_speed = speed;
}

float FFmpegVideoPuller::getSpeed() const
{
    std::lock_guard<std::mutex> lock(m_speedMutex);
    return m_speed;
}

void FFmpegVideoPuller::start()
{
    if (m_running)
        return;
    m_running = true;

    // 初始化PTS
    m_videoPts = 0.0;
    m_audioPts = 0.0;

    // 解码线程
    m_decodeThread = QThread::create([this]() { this->decodeLoop(); });
    m_decodeThread->start();

    // 视频播放线程
    m_videoPlayThread = QThread::create([this]() { this->videoPlayLoop(); });
    m_videoPlayThread->start();

    // 音频播放线程
    m_audioPlayThread = QThread::create([this]() { this->audioPlayLoop(); });
    m_audioPlayThread->start();
}

void FFmpegVideoPuller::stop()
{
    m_running = false;
    if (m_decodeThread) {
        m_decodeThread->quit();
        m_decodeThread->wait();
        delete m_decodeThread;
        m_decodeThread = nullptr;
    }
    if (m_videoPlayThread) {
        m_videoPlayThread->quit();
        m_videoPlayThread->wait();
        delete m_videoPlayThread;
        m_videoPlayThread = nullptr;
    }
    if (m_audioPlayThread) {
        m_audioPlayThread->quit();
        m_audioPlayThread->wait();
        delete m_audioPlayThread;
        m_audioPlayThread = nullptr;
    }
    // 释放缓冲区
    if (m_videoBuffer) {
        m_videoBuffer->clear();
        delete m_videoBuffer;
        m_videoBuffer = nullptr;
    }
    if (m_audioBuffer) {
        m_audioBuffer->clear();
        delete m_audioBuffer;
        m_audioBuffer = nullptr;
    }
    // 释放FFmpeg资源
    if (m_videoCodecCtx)
        avcodec_free_context(&m_videoCodecCtx);
    if (m_audioCodecCtx)
        avcodec_free_context(&m_audioCodecCtx);
    if (m_fmtCtx)
        avformat_close_input(&m_fmtCtx);
}

void FFmpegVideoPuller::decodeLoop()
{
    AVPacket* pkt = av_packet_alloc();
    AVFrame* frame = av_frame_alloc();

    while (m_running) {
        if (av_read_frame(m_fmtCtx, pkt) < 0) {
            std::this_thread::sleep_for(std::chrono::milliseconds(10));
            continue;
        }
        if (pkt->stream_index == m_videoStreamIdx) {
            avcodec_send_packet(m_videoCodecCtx, pkt);
            while (avcodec_receive_frame(m_videoCodecCtx, frame) == 0) {
                double pts = frame->best_effort_timestamp
                             * av_q2d(m_fmtCtx->streams[m_videoStreamIdx]->time_base);
                m_videoBuffer->push(av_frame_clone(frame), pts);
            }
        } else if (pkt->stream_index == m_audioStreamIdx) {
            avcodec_send_packet(m_audioCodecCtx, pkt);
            while (avcodec_receive_frame(m_audioCodecCtx, frame) == 0) {
                double pts = frame->best_effort_timestamp
                             * av_q2d(m_fmtCtx->streams[m_audioStreamIdx]->time_base);
                //qDebug() << "解码到音频帧, pts=" << pts << " nb_samples=" << frame->nb_samples;
                m_audioBuffer->push(av_frame_clone(frame), pts);
            }
        }
        av_packet_unref(pkt);
    }
    av_frame_free(&frame);
    av_packet_free(&pkt);
}

void FFmpegVideoPuller::videoPlayLoop()
{
    // 如果没有视频流，直接返回
    if (m_videoStreamIdx == -1) {
        return;
    }

    while (m_running) {
        AVFrame* vFrame = getCurrentVideoFrame();
        if (!vFrame) {
            std::this_thread::sleep_for(std::chrono::milliseconds(5));
            continue;
        }
        
        double vPts = vFrame->best_effort_timestamp
                      * av_q2d(m_fmtCtx->streams[m_videoStreamIdx]->time_base);
        
        // 更新视频PTS
        m_videoPts = vPts;
        
        // 渲染视频帧
        if (m_videoRenderCallback) {
            m_videoRenderCallback(vFrame);
        }

        // 控制倍速
        AVRational fr = m_fmtCtx->streams[m_videoStreamIdx]->avg_frame_rate;
        double frame_delay = 1.0 / (fr.num ? av_q2d(fr) : 25.0);
        float speed = getSpeed();
        int delay = int(frame_delay * 1000 / speed);
        
        // 如果只有视频没有音频，直接按照视频帧率播放
        if (m_audioStreamIdx == -1) {
            if (delay > 0) {
                std::this_thread::sleep_for(std::chrono::milliseconds(delay));
            }
        } else {
            // 有音频时，需要考虑音视频同步
            double aPts = m_audioPts.load();
            
            // 如果视频比音频快太多，等待音频追上
            if (vPts > aPts + 0.1) {
                std::this_thread::sleep_for(std::chrono::milliseconds(10));
                continue; // 不前进到下一帧，等待音频追上
            }
            
            // 正常播放速度控制
            if (delay > 0) {
                std::this_thread::sleep_for(std::chrono::milliseconds(delay));
            }
        }
        
        // 前进到下一帧
        nextVideoFrame();
        
        // 更新当前pts（用于进度显示）
        {
            std::lock_guard<std::mutex> lock(m_ptsMutex);
            m_currentPts = vPts;
        }
    }
}

void FFmpegVideoPuller::audioPlayLoop()
{
    // 如果没有音频流，直接返回
    if (m_audioStreamIdx == -1) {
        return;
    }
    
    while (m_running) {
        // 获取当前音频帧
        AVFrame* aFrame = getCurrentAudioFrame();
        if (!aFrame) {
            std::this_thread::sleep_for(std::chrono::milliseconds(5));
            continue;
        }
        
        // 计算音频PTS
        double aPts = aFrame->best_effort_timestamp
                      * av_q2d(m_fmtCtx->streams[m_audioStreamIdx]->time_base);
        
        // 更新音频PTS
        m_audioPts = aPts;
        
        // 如果只有音频没有视频，直接播放音频
        if (m_videoStreamIdx == -1) {
            // 播放音频帧
            if (m_audioPlayCallback) {
                m_audioPlayCallback(aFrame);
            }
            
            // 更新当前pts（用于进度显示）
            {
                std::lock_guard<std::mutex> lock(m_ptsMutex);
                m_currentPts = aPts;
            }
            
            // 前进到下一帧
            nextAudioFrame();
            
            // 控制音频播放速度
            float speed = getSpeed();
            int samples = aFrame->nb_samples;
            int sample_rate = aFrame->sample_rate;
            double frame_duration = samples / (double)sample_rate;
            int delay = int(frame_duration * 1000 / speed);
            if (delay > 0) {
                std::this_thread::sleep_for(std::chrono::milliseconds(delay));
            }
            
            continue; // 继续下一帧处理
        }
        
        // 有视频时，需要考虑音视频同步
        double vPts = m_videoPts.load();
        
        // 如果音频PTS超前于视频PTS太多，等待视频追上
        if (aPts > vPts + 0.1) {
            std::this_thread::sleep_for(std::chrono::milliseconds(5));
            continue; // 不前进到下一帧，等待视频追上
        }
        
        // 如果音频比视频慢太多，可能需要跳过一些音频帧来追赶视频
        if (aPts < vPts - 0.2) {
            // 跳过当前音频帧，直接前进
            nextAudioFrame();
            continue;
        }
        
        // 播放音频帧
        if (m_audioPlayCallback) {
            m_audioPlayCallback(aFrame);
        }
        
        // 前进到下一帧
        nextAudioFrame();
        
        // 控制音频播放速度，与视频保持一致
        float speed = getSpeed();
        if (speed != 1.0f) {
            // 根据倍速调整音频播放间隔
            int samples = aFrame->nb_samples;
            int sample_rate = aFrame->sample_rate;
            double frame_duration = samples / (double)sample_rate;
            int delay = int(frame_duration * 1000 / speed);
            if (delay > 0) {
                std::this_thread::sleep_for(std::chrono::milliseconds(delay));
            }
        }
    }
}

// 进度相关
double FFmpegVideoPuller::getFirstPts() const
{
    return m_videoBuffer ? m_videoBuffer->firstPts() : 0.0;
}
double FFmpegVideoPuller::getLastPts() const
{
    return m_videoBuffer ? m_videoBuffer->lastPts() : 0.0;
}
double FFmpegVideoPuller::getCurrentPts() const
{
    std::lock_guard<std::mutex> lock(m_ptsMutex);
    return m_currentPts;
}
void FFmpegVideoPuller::seekToPts(double pts)
{
    // 停止线程
    m_running = false;
    if (m_decodeThread) { m_decodeThread->quit(); m_decodeThread->wait(); delete m_decodeThread; m_decodeThread = nullptr; }
    if (m_videoPlayThread) { m_videoPlayThread->quit(); m_videoPlayThread->wait(); delete m_videoPlayThread; m_videoPlayThread = nullptr; }
    if (m_audioPlayThread) { m_audioPlayThread->quit(); m_audioPlayThread->wait(); delete m_audioPlayThread; m_audioPlayThread = nullptr; }
    
    // 清空缓冲区
    if (m_videoBuffer) m_videoBuffer->clear();
    if (m_audioBuffer) m_audioBuffer->clear();
    
    // FFmpeg seek
    int64_t seek_target = pts / av_q2d(m_fmtCtx->streams[m_videoStreamIdx]->time_base);
    av_seek_frame(m_fmtCtx, m_videoStreamIdx, seek_target, AVSEEK_FLAG_BACKWARD);
    avcodec_flush_buffers(m_videoCodecCtx);
    if (m_audioCodecCtx) avcodec_flush_buffers(m_audioCodecCtx);
    
    // 重置索引
    m_videoPlayIndex = 0;
    m_audioPlayIndex = 0;
    
    // 重置PTS
    m_videoPts = pts;
    m_audioPts = pts;
    m_currentPts = pts;
    
    // 重新启动线程
    m_running = true;
    m_decodeThread = QThread::create([this]() { this->decodeLoop(); });
    m_decodeThread->start();
    m_videoPlayThread = QThread::create([this]() { this->videoPlayLoop(); });
    m_videoPlayThread->start();
    m_audioPlayThread = QThread::create([this]() { this->audioPlayLoop(); });
    m_audioPlayThread->start();
}

// 取帧接口
AVFrame* FFmpegVideoPuller::getCurrentVideoFrame()
{
    if (!m_videoBuffer)
        return nullptr;
    return m_videoBuffer->get(m_videoPlayIndex);
}
AVFrame* FFmpegVideoPuller::getCurrentAudioFrame()
{
    if (!m_audioBuffer)
        return nullptr;
    return m_audioBuffer->get(m_audioPlayIndex);
}
void FFmpegVideoPuller::nextVideoFrame()
{
    ++m_videoPlayIndex;
    if (m_videoBuffer && m_videoPlayIndex >= m_videoBuffer->size())
        m_videoPlayIndex = m_videoBuffer->size() - 1;
}
void FFmpegVideoPuller::nextAudioFrame()
{
    ++m_audioPlayIndex;
    if (m_audioBuffer && m_audioPlayIndex >= m_audioBuffer->size())
        m_audioPlayIndex = m_audioBuffer->size() - 1;
}
size_t FFmpegVideoPuller::videoBufferSize() const
{
    return m_videoBuffer ? m_videoBuffer->size() : 0;
}
size_t FFmpegVideoPuller::audioBufferSize() const
{
    return m_audioBuffer ? m_audioBuffer->size() : 0;
}