/*************************************************************************/
/*  scroll_bar.h                                                         */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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/*************************************************************************/

#ifndef SCROLL_BAR_H
#define SCROLL_BAR_H

#include "scene/gui/range.h"

class ScrollBar : public Range {
	GDCLASS(ScrollBar, Range);

	enum HighlightStatus {
		HIGHLIGHT_NONE,
		HIGHLIGHT_DECR,
		HIGHLIGHT_RANGE,
		HIGHLIGHT_INCR,
	};

	static bool focus_by_default;

	Orientation orientation;
	Size2 size;
	float custom_step = -1.0;

	HighlightStatus highlight = HIGHLIGHT_NONE;

	bool incr_active = false;
	bool decr_active = false;

	struct Drag {
		bool active = false;
		float pos_at_click = 0.0;
		float value_at_click = 0.0;
	} drag;

	double get_grabber_size() const;
	double get_grabber_min_size() const;
	double get_area_size() const;
	double get_area_offset() const;
	double get_grabber_offset() const;

	static void set_can_focus_by_default(bool p_can_focus);

	Node *drag_node = nullptr;
	NodePath drag_node_path;
	bool drag_node_enabled = true;

	Vector2 drag_node_speed = Vector2();
	Vector2 drag_node_accum;
	Vector2 drag_node_from;
	Vector2 last_drag_node_accum;
	float last_drag_node_time = 0.0;
	float time_since_motion = 0.0;
	bool drag_node_touching = false;
	bool drag_node_touching_deaccel = false;
	bool click_handled = false;

	bool scrolling = false;
	double target_scroll = 0.0;
	bool smooth_scroll_enabled = false;

	void _drag_node_exit();
	void _drag_node_input(const Ref<InputEvent> &p_input);

	virtual void gui_input(const Ref<InputEvent> &p_event) override;

protected:
	void _notification(int p_what);

	static void _bind_methods();

public:
	void set_custom_step(float p_custom_step);
	float get_custom_step() const;

	void set_drag_node(const NodePath &p_path);
	NodePath get_drag_node() const;
	void set_drag_node_enabled(bool p_enable);

	void set_smooth_scroll_enabled(bool p_enable);
	bool is_smooth_scroll_enabled() const;

	virtual Size2 get_minimum_size() const override;
	ScrollBar(Orientation p_orientation = VERTICAL);
	~ScrollBar();
};

class HScrollBar : public ScrollBar {
	GDCLASS(HScrollBar, ScrollBar);

public:
	HScrollBar() :
			ScrollBar(HORIZONTAL) { set_v_size_flags(0); }
};

class VScrollBar : public ScrollBar {
	GDCLASS(VScrollBar, ScrollBar);

public:
	VScrollBar() :
			ScrollBar(VERTICAL) { set_h_size_flags(0); }
};

#endif