#ifndef MOUSEEVENTSPY_H
#define MOUSEEVENTSPY_H

#include <QObject>
#include <QEvent>

/**
 * @brief Catches all mouse events and reports them via signal.
 *
 * Based on
 * https://stackoverflow.com/questions/46173105/how-can-i-reset-a-timer-every-time-i-receive-a-touch-event-from-a-qml-page
 */
class MouseEventSpy : public QObject
{
    Q_OBJECT

protected:
    explicit MouseEventSpy(QObject *parent = nullptr) : QObject(parent) { /* nothing */ }

signals:
    void mouseEventDetected();

public:
    /**
     * @brief Create instance if necessary.
     *
     * If no instance has been created yet, create new instance and install it as event filter
     * in QGuiApplication.
     *
     * @see MouseEventSpy::instance()
     */
    static void init();
    /**
     * @brief Implements the singleton pattern.
     * @return Instance of MouseEventSpy
     *
     * If no instance has been created yet, create new instance and install it as event filter
     * in QGuiApplication.
     */
    static MouseEventSpy* instance();

protected:
    /**
     * @brief Expand QObject::eventFilter to react to MouseEvents.
     *
     * Restart timer each time a mouse event is detected.
     */
    bool eventFilter(QObject* watched, QEvent* event);

private:
    /**
     * @brief Checks whether the event type is a mouse event.
     * @param t Event type
     * @return Returns whether the event type is a mouse event.
     */
    bool isMouseEvent(QEvent::Type t);

};

#endif // MOUSEEVENTSPY_H