#pragma once
#include <QObject>
#include <QImage>
#include <QString>
#include <atomic>
#include <thread>

class V4l2Worker : public QObject
{
    Q_OBJECT

public:
    explicit V4l2Worker(QObject *parent = nullptr);
    ~V4l2Worker();

public slots:
    void startCapture(const QString &device, int width = 1920, int height = 1080);
    void stopCapture();

signals:
    void newFrame(const QImage &frame);
    void captureStarted(const QString &device, int width, int height, const QString &format);
    void captureStopped();
    void errorOccurred(const QString &message);

private:
    void stop();           // joins m_captureThread, closes device – safe from any thread
    void captureLoop();    // runs inside m_captureThread
    bool openDevice(const QString &device, int width, int height);
    void closeDevice();
    bool initMmap();
    void freeMmap();
    QImage convertToImage(const void *data, size_t size, int width, int height);
    QImage yuyv2Rgb(const uchar *src, int width, int height);
    QImage nv122Rgb(const uchar *src, int width, int height);

    int           m_fd       = -1;
    int           m_width    = 1920;
    int           m_height   = 1080;
    uint32_t      m_pixFmt   = 0;

    static constexpr int MMAP_BUFFERS = 4;
    struct MmapBuffer { void *start = nullptr; size_t length = 0; };
    MmapBuffer    m_buffers[MMAP_BUFFERS];
    int           m_nBuffers = 0;

    std::atomic<bool> m_running{false};
    std::thread       m_captureThread;   // dedicated capture thread – not the Qt event thread
};