#pragma once
#include <QWidget>
#include <QImage>
#include <QLabel>
#include <QPushButton>
#include <QComboBox>
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QThread>
#include <QTimer>

#include "v4l2worker.h"

// VideoWidget shows a live preview of a V4L2 capture device.
// It lives in the right-side panel, below the Tag Monitor.
// Features:
//   - Device selector (auto-enumerates /dev/video*)
//   - Start / Stop capture
//   - Freeze-frame toggle
//   - Screenshot (saves current frame as PNG/JPG)
//   - Frame is scaled to fit the widget while keeping aspect ratio
class VideoWidget : public QWidget
{
    Q_OBJECT

public:
    explicit VideoWidget(QWidget *parent = nullptr);
    ~VideoWidget();

public:
    // Called by MainWindow::closeEvent to guarantee orderly shutdown before
    // widget destruction. Safe to call multiple times.
    void shutdown();

public slots:
    void onNewFrame(const QImage &frame);

private slots:
    void onStartStop();
    void onFreeze(bool frozen);
    void onScreenshot();
    void refreshDeviceList();

protected:
    void paintEvent(QPaintEvent *event) override;
    void resizeEvent(QResizeEvent *event) override;

private:
    void setupUi();
    void startCapture();
    void stopCapture();
    void updateScaled();

    // Worker
    QThread     *m_thread = nullptr;
    V4l2Worker  *m_worker = nullptr;

    // Current frame
    QImage  m_frame;
    QImage  m_scaled;
    bool    m_frozen       = false;
    bool    m_running      = false;
    bool    m_shutdownDone = false;

    // UI
    QComboBox   *m_deviceCombo  = nullptr;
    QPushButton *m_startBtn     = nullptr;
    QPushButton *m_freezeBtn    = nullptr;
    QPushButton *m_screenshotBtn= nullptr;
    QLabel      *m_infoLabel    = nullptr;
};