#ifndef SCENE_MAIN_LOOP_H
#define SCENE_MAIN_LOOP_H

/*  scene_tree.h                                                         */


#include "core/containers/self_list.h"
#include "core/io/multiplayer_api.h"
#include "core/os/main_loop.h"
#include "core/os/thread_safe.h"

class PackedScene;
class Node;
class SceneTreeTween;
class ShortCut;
class Viewport;
class Material;
class Mesh;
class ArrayMesh;

class SceneTreeTimer : public Reference {
	GDCLASS(SceneTreeTimer, Reference);

	float time_left;
	bool process_pause;
	bool ignore_time_scale = false;

protected:
	static void _bind_methods();

public:
	void set_time_left(float p_time);
	float get_time_left() const;

	void set_pause_mode_process(bool p_pause_mode_process);
	bool is_pause_mode_process();

	void set_ignore_time_scale(bool p_ignore);
	bool is_ignore_time_scale();

	void release_connections();

	SceneTreeTimer();
};

class SceneTree : public MainLoop {
	_THREAD_SAFE_CLASS_

	GDCLASS(SceneTree, MainLoop);

public:
	typedef void (*IdleCallback)();

	enum StretchMode {

		STRETCH_MODE_DISABLED,
		STRETCH_MODE_2D,
		STRETCH_MODE_VIEWPORT,
	};

	enum StretchAspect {

		STRETCH_ASPECT_IGNORE,
		STRETCH_ASPECT_KEEP,
		STRETCH_ASPECT_KEEP_WIDTH,
		STRETCH_ASPECT_KEEP_HEIGHT,
		STRETCH_ASPECT_EXPAND,
	};

private:
	struct Group {
		Vector<Node *> nodes;
		//uint64_t last_tree_version;
		bool changed;
		Group() { changed = false; };
	};

	Viewport *root;

	uint64_t tree_version;
	float physics_process_time;
	float idle_process_time;
	bool accept_quit;
	bool quit_on_go_back;

#ifdef DEBUG_ENABLED
	bool debug_collisions_hint;
	bool debug_navigation_hint;
	bool debug_paths_hint;
#endif
	bool pause;
	int root_lock;

	RBMap<StringName, Group> group_map;
	bool _quit;
	bool initialized;
	bool input_handled;

	Size2 last_screen_size;
	StringName tree_changed_name;
	StringName node_added_name;
	StringName node_removed_name;
	StringName node_renamed_name;

	bool use_font_oversampling;
	int64_t current_frame;
	int64_t current_event;
	int node_count;
	struct UGCall {
		StringName group;
		StringName call;

		bool operator<(const UGCall &p_with) const { return group == p_with.group ? call < p_with.call : group < p_with.group; }
	};

	//safety for when a node is deleted while a group is being called
	int call_lock;
	RBSet<Node *> call_skip; //skip erased nodes

	StretchMode stretch_mode;
	StretchAspect stretch_aspect;
	Size2i stretch_min;
	real_t stretch_scale;

	void _update_font_oversampling(float p_ratio);
	void _update_root_rect();

	struct DeleteQueueElement {
		ObjectID id;
		int32_t child_list_id;
	};
	LocalVector<DeleteQueueElement> delete_queue;

	RBMap<UGCall, Vector<Variant>> unique_group_calls;
	bool ugc_locked;
	void _flush_ugc();

	_FORCE_INLINE_ void _update_group_order(Group &g, bool p_use_priority = false);

	Array _get_nodes_in_group(const StringName &p_group);

	Node *current_scene;

	Color debug_collisions_color;
	Color debug_collision_contact_color;
	Color debug_paths_color;
	float debug_paths_width = 1.0f;
	Ref<ArrayMesh> debug_contact_mesh;
	Ref<Material> debug_paths_material;
	Ref<Material> collision_material;
	int collision_debug_contacts;

	void _change_scene(Node *p_to);
	//void _call_group(uint32_t p_call_flags,const StringName& p_group,const StringName& p_function,const Variant& p_arg1,const Variant& p_arg2);

	List<Ref<SceneTreeTimer>> timers;
	List<Ref<SceneTreeTween>> tweens;

	///network///

	Ref<MultiplayerAPI> multiplayer;
	bool multiplayer_poll;

	void _network_peer_connected(int p_id);
	void _network_peer_disconnected(int p_id);

	void _connected_to_server();
	void _connection_failed();
	void _server_disconnected();

	static SceneTree *singleton;
	friend class Node;

	void tree_changed();
	void node_added(Node *p_node);
	void node_removed(Node *p_node);
	void node_renamed(Node *p_node);
	void process_tweens(float p_delta, bool p_physics_frame);

	Group *add_to_group(const StringName &p_group, Node *p_node);
	void remove_from_group(const StringName &p_group, Node *p_node);
	void make_group_changed(const StringName &p_group);

	void _notify_group_pause(const StringName &p_group, int p_notification);
	Variant _call_group_flags(const Variant **p_args, int p_argcount, Variant::CallError &r_error);
	Variant _call_group(const Variant **p_args, int p_argcount, Variant::CallError &r_error);

	enum CallInputType {
		CALL_INPUT_TYPE_INPUT,
		CALL_INPUT_TYPE_SHORTCUT_INPUT,
		CALL_INPUT_TYPE_UNHANDLED_INPUT,
		CALL_INPUT_TYPE_UNHANDLED_KEY_INPUT,
	};

	void _call_input_pause(const StringName &p_group, const CallInputType p_call_type, const Ref<InputEvent> &p_input);

	void _flush_delete_queue();
	//optimization
	friend class CanvasItem;
	friend class Viewport;

	SelfList<Node>::List xform_change_list;

	Ref<ShortCut> debugger_stop_shortcut;

	enum {
		MAX_IDLE_CALLBACKS = 256
	};

	static IdleCallback idle_callbacks[MAX_IDLE_CALLBACKS];
	static int idle_callback_count;
	void _call_idle_callbacks();

protected:
	void _notification(int p_notification);
	static void _bind_methods();

public:
	enum {
		NOTIFICATION_TRANSFORM_CHANGED = 2000
	};

	enum GroupCallFlags {
		GROUP_CALL_DEFAULT = 0,
		GROUP_CALL_REVERSE = 1,
		GROUP_CALL_REALTIME = 2,
		GROUP_CALL_UNIQUE = 4,
		GROUP_CALL_MULTILEVEL = 8,
	};

	_FORCE_INLINE_ Viewport *get_root() const {
		return root;
	}

	void call_group_flags(uint32_t p_call_flags, const StringName &p_group, const StringName &p_function, VARIANT_ARG_LIST);
	void notify_group_flags(uint32_t p_call_flags, const StringName &p_group, int p_notification);
	void set_group_flags(uint32_t p_call_flags, const StringName &p_group, const String &p_name, const Variant &p_value);

	void call_group(const StringName &p_group, const StringName &p_function, VARIANT_ARG_LIST);
	void notify_group(const StringName &p_group, int p_notification);
	void set_group(const StringName &p_group, const String &p_name, const Variant &p_value);

	void flush_transform_notifications();

	virtual void input_text(const String &p_text);
	virtual void input_event(const Ref<InputEvent> &p_event);
	virtual void init();

	virtual void iteration_prepare();
	virtual bool iteration(float p_time);
	virtual void iteration_end();
	virtual bool idle(float p_time);

	virtual void finish();

	bool is_auto_accept_quit() const;
	void set_auto_accept_quit(bool p_enable);
	bool is_quit_on_go_back() const;
	void set_quit_on_go_back(bool p_enable);

	void quit(int p_exit_code = -1);

	void set_input_as_handled();
	bool is_input_handled();
	_FORCE_INLINE_ float get_physics_process_time() const {
		return physics_process_time;
	}
	_FORCE_INLINE_ float get_idle_process_time() const {
		return idle_process_time;
	}

	void set_pause(bool p_enabled);
	bool is_paused() const;

#ifdef DEBUG_ENABLED
	void set_debug_collisions_hint(bool p_enabled);
	bool is_debugging_collisions_hint() const;

	void set_debug_navigation_hint(bool p_enabled);
	bool is_debugging_navigation_hint() const;

	void set_debug_paths_hint(bool p_enabled);
	bool is_debugging_paths_hint() const;
#else
	void set_debug_collisions_hint(bool p_enabled) {}
	bool is_debugging_collisions_hint() const {
		return false;
	}

	void set_debug_navigation_hint(bool p_enabled) {}
	bool is_debugging_navigation_hint() const {
		return false;
	}

	void set_debug_paths_hint(bool p_enabled) {}
	bool is_debugging_paths_hint() const {
		return false;
	}
#endif

	void set_debug_collisions_color(const Color &p_color);
	Color get_debug_collisions_color() const;

	void set_debug_collision_contact_color(const Color &p_color);
	Color get_debug_collision_contact_color() const;

	void set_debug_paths_color(const Color &p_color);
	Color get_debug_paths_color() const;

	void set_debug_paths_width(float p_width);
	float get_debug_paths_width() const;

	Ref<Material> get_debug_paths_material();
	Ref<Material> get_debug_collision_material();
	Ref<ArrayMesh> get_debug_contact_mesh();

	int get_collision_debug_contact_count() {
		return collision_debug_contacts;
	}

	int64_t get_frame() const;
	int64_t get_event_count() const;

	int get_node_count() const;

	void queue_delete(Object *p_object);

	void get_nodes_in_group(const StringName &p_group, List<Node *> *p_list);
	Node *get_first_node_in_group(const StringName &p_group);
	bool has_group(const StringName &p_identifier) const;

	void set_screen_stretch(StretchMode p_mode, StretchAspect p_aspect, const Size2 &p_minsize, real_t p_scale = 1.0);

	void set_use_font_oversampling(bool p_oversampling);
	bool is_using_font_oversampling() const;

	//void change_scene(const String& p_path);
	//Node *get_loaded_scene();

	void set_current_scene(Node *p_scene);
	Node *get_current_scene() const;
	Error change_scene(const String &p_path);
	Error change_scene_to(const Ref<PackedScene> &p_scene);
	Error reload_current_scene();

	Ref<SceneTreeTimer> create_timer(float p_delay_sec, bool p_process_pause = true);
	Ref<SceneTreeTween> create_tween();
	Array get_processed_tweens();

	//used by Main::start, don't use otherwise
	void add_current_scene(Node *p_current);

	static SceneTree *get_singleton() {
		return singleton;
	}

	void drop_files(const Vector<String> &p_files, int p_from_screen = 0);
	void global_menu_action(const Variant &p_id, const Variant &p_meta);
	void get_argument_options(const StringName &p_function, int p_idx, List<String> *r_options, const String &quote_style) const;

	//network API

	Ref<MultiplayerAPI> get_multiplayer() const;
	void set_multiplayer_poll_enabled(bool p_enabled);
	bool is_multiplayer_poll_enabled() const;
	void set_multiplayer(Ref<MultiplayerAPI> p_multiplayer);
	void set_network_peer(const Ref<NetworkedMultiplayerPeer> &p_network_peer);
	Ref<NetworkedMultiplayerPeer> get_network_peer() const;
	bool is_network_server() const;
	bool has_network_peer() const;
	int get_network_unique_id() const;
	Vector<int> get_network_connected_peers() const;
	int get_rpc_sender_id() const;

	void set_refuse_new_network_connections(bool p_refuse);
	bool is_refusing_new_network_connections() const;

	static void add_idle_callback(IdleCallback p_callback);
	SceneTree();
	~SceneTree();
};

VARIANT_ENUM_CAST(SceneTree::StretchMode);
VARIANT_ENUM_CAST(SceneTree::StretchAspect);
VARIANT_ENUM_CAST(SceneTree::GroupCallFlags);

#endif