#ifndef FANCYKNOB_H
#define FANCYKNOB_H

#include <nanogui/widget.h>

NAMESPACE_BEGIN(nanogui)

class NANOGUI_EXPORT FancyKnob : public Widget {
public:
    FancyKnob(Widget* parent, int rad = 80);

    float value() const { return m_value; }
    void set_value(float value)
    {
        if (value != m_value)
            m_value = value;
    }

    float min_default() const { return m_default; }
    void set_default(float value) { m_default = value; }

    float min_value() const { return m_min_val; }
    void set_min_value(float value);

    float max_value() const { return m_max_val; }
    void set_max_value(float value);

    float increment() const { return m_increment; }
    void set_increment(float value) { m_increment = value; }

    float scroll_speed() const { return m_scroll_speed; }
    void set_scroll_speed(float value);

    const Color& gauge_color() const { return m_gauge_color; }
    void set_gauge_color(const Color& color);

    std::function<void(float)> callback() const { return m_callback; }
    void set_callback(const std::function<void(float)>& callback) { m_callback = callback; }

    virtual Vector2i preferred_size(NVGcontext* ctx) const override;
    virtual bool mouse_enter_event(const Vector2i& p, bool enter);
    virtual bool mouse_drag_event(const Vector2i& p, const Vector2i& rel, int button, int modifiers) override;
    virtual bool mouse_button_event(const Vector2i& p, int button, bool down, int modifiers) override;
    virtual bool scroll_event(const Vector2i& p, const Vector2f& rel) override;
    virtual bool keyboard_event(int key, int scancode, int action, int modifiers);
    virtual void draw(NVGcontext* ctx) override;

protected:
    bool adjust_value(float value, float incr);

private:
    static const float m_pi;

    // colors
    Color
        m_gauge_color,
        m_gauge_bg_color,
        m_knob_color_1,
        m_knob_color_2,
        m_outline_color_1,
        m_outline_color_2;

    // sizes, value and range
    float
        m_value,
        m_min_val,
        m_max_val,
        m_default,
        m_increment,
        m_scroll_speed,
        m_scroll_increment,
        m_drag_increment,
        /* value gauge width as ratio of knob radius */
        m_gauge_width,
        /* value indicator line length as ratio of knob radius */
        m_indicator_size;

    // behaviour
    bool m_fine_mode = false;
    std::function<void(float)> m_callback;
};

NAMESPACE_END(nanogui)

#endif // FANCYKNOB_H