/**************************************************************************/
/*  curve_editor_plugin.h                                                 */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
/*                        https://godotengine.org                         */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
/*                                                                        */
/* Permission is hereby granted, free of charge, to any person obtaining  */
/* a copy of this software and associated documentation files (the        */
/* "Software"), to deal in the Software without restriction, including    */
/* without limitation the rights to use, copy, modify, merge, publish,    */
/* distribute, sublicense, and/or sell copies of the Software, and to     */
/* permit persons to whom the Software is furnished to do so, subject to  */
/* the following conditions:                                              */
/*                                                                        */
/* The above copyright notice and this permission notice shall be         */
/* included in all copies or substantial portions of the Software.        */
/*                                                                        */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
/**************************************************************************/

#ifndef CURVE_EDITOR_PLUGIN_H
#define CURVE_EDITOR_PLUGIN_H

#include "editor/editor_inspector.h"
#include "editor/editor_plugin.h"
#include "editor/editor_resource_preview.h"
#include "scene/resources/curve.h"

class PopupMenu;

// Edits a y(x) curve
class CurveEditor : public Control {
	GDCLASS(CurveEditor, Control);

public:
	CurveEditor();

	Size2 get_minimum_size() const override;

	void set_curve(Ref<Curve> curve);

	enum PresetID {
		PRESET_FLAT0 = 0,
		PRESET_FLAT1,
		PRESET_LINEAR,
		PRESET_EASE_IN,
		PRESET_EASE_OUT,
		PRESET_SMOOTHSTEP,
		PRESET_COUNT
	};

	enum ContextAction {
		CONTEXT_ADD_POINT = 0,
		CONTEXT_REMOVE_POINT,
		CONTEXT_LINEAR,
		CONTEXT_LEFT_LINEAR,
		CONTEXT_RIGHT_LINEAR
	};

	enum TangentIndex {
		TANGENT_NONE = -1,
		TANGENT_LEFT = 0,
		TANGENT_RIGHT = 1
	};

protected:
	void _notification(int p_what);

private:
	virtual void gui_input(const Ref<InputEvent> &p_event) override;
	void on_preset_item_selected(int preset_id);
	void _curve_changed();
	void on_context_menu_item_selected(int action_id);

	void open_context_menu(Vector2 pos);
	int get_point_at(Vector2 pos) const;
	TangentIndex get_tangent_at(Vector2 pos) const;
	void add_point(Vector2 pos);
	void remove_point(int index);
	void toggle_linear(TangentIndex tangent = TANGENT_NONE);
	void set_selected_point(int index);
	void set_hover_point_index(int index);
	void update_view_transform();

	Vector2 get_tangent_view_pos(int i, TangentIndex tangent) const;
	Vector2 get_view_pos(Vector2 world_pos) const;
	Vector2 get_world_pos(Vector2 view_pos) const;

	void _draw();

private:
	Transform2D _world_to_view;

	Ref<Curve> _curve_ref;
	PopupMenu *_context_menu = nullptr;
	PopupMenu *_presets_menu = nullptr;

	Array _undo_data;
	bool _has_undo_data;

	Vector2 _context_click_pos;
	int _selected_point;
	int _hover_point;
	TangentIndex _selected_tangent;
	bool _dragging;

	// Constant
	float _hover_radius;
	float _tangents_length;
	float _gizmo_handle_scale = 1.0;
};

class EditorInspectorPluginCurve : public EditorInspectorPlugin {
	GDCLASS(EditorInspectorPluginCurve, EditorInspectorPlugin);

public:
	virtual bool can_handle(Object *p_object) override;
	virtual void parse_begin(Object *p_object) override;
};

class CurveEditorPlugin : public EditorPlugin {
	GDCLASS(CurveEditorPlugin, EditorPlugin);

public:
	CurveEditorPlugin();

	virtual String get_name() const override { return "Curve"; }
};

class CurvePreviewGenerator : public EditorResourcePreviewGenerator {
	GDCLASS(CurvePreviewGenerator, EditorResourcePreviewGenerator);

public:
	virtual bool handles(const String &p_type) const override;
	virtual Ref<Texture2D> generate(const Ref<Resource> &p_from, const Size2 &p_size) const override;
};

#endif // CURVE_EDITOR_PLUGIN_H