/**************************************************************************/
/*  scroll_container.h                                                    */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
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/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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/* Permission is hereby granted, free of charge, to any person obtaining  */
/* a copy of this software and associated documentation files (the        */
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/* without limitation the rights to use, copy, modify, merge, publish,    */
/* distribute, sublicense, and/or sell copies of the Software, and to     */
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/**************************************************************************/

#pragma once

#include "scene/gui/container.h"
#include "scene/gui/scroll_bar.h"

class PanelContainer;
class TextureRect;

class ScrollContainer : public Container {
	GDCLASS(ScrollContainer, Container);

public:
	enum ScrollMode {
		SCROLL_MODE_DISABLED = 0,
		SCROLL_MODE_AUTO,
		SCROLL_MODE_SHOW_ALWAYS,
		SCROLL_MODE_SHOW_NEVER,
		SCROLL_MODE_RESERVE,
		SCROLL_MODE_MAXIMIZE_FIRST,
	};

	enum ScrollHintMode {
		SCROLL_HINT_MODE_DISABLED,
		SCROLL_HINT_MODE_ALL,
		SCROLL_HINT_MODE_TOP_AND_LEFT,
		SCROLL_HINT_MODE_BOTTOM_AND_RIGHT,
	};

private:
	HScrollBar *h_scroll = nullptr;
	VScrollBar *v_scroll = nullptr;
	PanelContainer *focus_panel = nullptr;

	mutable Size2 largest_child_min_size; // The largest one among the min sizes of all available child controls.

	void _update_scrollbars();

	Vector2 drag_speed;
	Vector2 drag_accum;
	Vector2 drag_from;
	Vector2 last_drag_accum;
	float time_since_motion = 0.0f;
	bool drag_touching = false;
	bool drag_touching_deaccel = false;
	bool beyond_deadzone = false;
	bool scroll_on_drag_hover = false;

	TextureRect *scroll_hint_top_left = nullptr;
	TextureRect *scroll_hint_bottom_right = nullptr;

	ScrollMode horizontal_scroll_mode = SCROLL_MODE_AUTO;
	ScrollMode vertical_scroll_mode = SCROLL_MODE_AUTO;

	void _update_scroll_hints();

	int deadzone = 0;
	bool follow_focus = false;
	int scroll_border = 20;
	int scroll_speed = 12;
	bool scroll_horizontal_by_default = false;

	ScrollHintMode scroll_hint_mode = SCROLL_HINT_MODE_DISABLED;
	bool tile_scroll_hint = false;

	struct ThemeCache {
		Ref<StyleBox> panel_style;
		Ref<StyleBox> focus_style;

		Ref<Texture2D> scroll_hint_vertical;
		Ref<Texture2D> scroll_hint_horizontal;

		Color scroll_hint_vertical_color;
		Color scroll_hint_horizontal_color;

		int scrollbar_h_separation = 0;
		int scrollbar_v_separation = 0;
	} theme_cache;

	void _cancel_drag();

	bool _is_h_scroll_visible() const;
	bool _is_v_scroll_visible() const;

	Rect2 _get_margins() const;

	bool draw_focus_border = false;
	bool focus_border_is_drawn = false;
	bool child_has_focus();

	Size2 _get_minimum_size(bool p_use_desired_sizes) const;

protected:
	Size2 get_minimum_size() const override;
	Size2 get_desired_size() const override;
	Size2 get_inner_combined_maximum_size() const override;

	void _gui_focus_changed(Control *p_control);
	void _reposition_children();

	void _notification(int p_what);
	static void _bind_methods();

	bool _updating_scrollbars = false;
	void _update_scrollbar_position();
	void _scroll_moved(float);

	void _accessibility_action_scroll_set(const Variant &p_data);
	void _accessibility_action_scroll_up(const Variant &p_data);
	void _accessibility_action_scroll_down(const Variant &p_data);
	void _accessibility_action_scroll_left(const Variant &p_data);
	void _accessibility_action_scroll_right(const Variant &p_data);

public:
	virtual void gui_input(const Ref<InputEvent> &p_gui_input) override;

	void set_h_scroll(int p_pos);
	int get_h_scroll() const;

	void set_v_scroll(int p_pos);
	int get_v_scroll() const;

	void set_horizontal_custom_step(float p_custom_step);
	float get_horizontal_custom_step() const;

	void set_vertical_custom_step(float p_custom_step);
	float get_vertical_custom_step() const;

	void set_horizontal_scroll_mode(ScrollMode p_mode);
	ScrollMode get_horizontal_scroll_mode() const;

	void set_vertical_scroll_mode(ScrollMode p_mode);
	ScrollMode get_vertical_scroll_mode() const;

	void set_scroll_horizontal_by_default(bool p_enable);
	bool is_scroll_horizontal_by_default() const;

	void set_deadzone(int p_deadzone);
	int get_deadzone() const;

	void set_scroll_hint_mode(ScrollHintMode p_mode);
	ScrollHintMode get_scroll_hint_mode() const;

	void set_tile_scroll_hint(bool p_enable);
	bool is_scroll_hint_tiled();

	bool is_following_focus() const;
	void set_follow_focus(bool p_follow);

	void set_scroll_on_drag_hover(bool p_scroll);

	HScrollBar *get_h_scroll_bar();
	VScrollBar *get_v_scroll_bar();
	void ensure_control_visible(Control *p_control);

	PackedStringArray get_configuration_warnings() const override;

	void set_draw_focus_border(bool p_draw);
	bool get_draw_focus_border();

	ScrollContainer();
};

VARIANT_ENUM_CAST(ScrollContainer::ScrollMode);
VARIANT_ENUM_CAST(ScrollContainer::ScrollHintMode);
