/**************************************************************************/
/*  animation_tree.h                                                      */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
/*                        https://godotengine.org                         */
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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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#ifndef ANIMATION_TREE_H
#define ANIMATION_TREE_H

#include "animation_player.h"
#include "scene/3d/node_3d.h"
#include "scene/3d/skeleton_3d.h"
#include "scene/resources/animation.h"
#include "scene/resources/audio_stream_polyphonic.h"

#define HUGE_LENGTH 31540000 // 31540000 seconds mean 1 year... is it too long? It must be longer than any Animation length and Transition xfade time to prevent time inversion.

class AnimationNodeBlendTree;
class AnimationNodeStartState;
class AnimationNodeEndState;
class AnimationPlayer;
class AnimationTree;

class AnimationNode : public Resource {
	GDCLASS(AnimationNode, Resource);

public:
	enum FilterAction {
		FILTER_IGNORE,
		FILTER_PASS,
		FILTER_STOP,
		FILTER_BLEND
	};

	struct Input {
		String name;
	};

	Vector<Input> inputs;

	friend class AnimationTree;

	struct AnimationState {
		Ref<Animation> animation;
		double time = 0.0;
		double delta = 0.0;
		Vector<real_t> track_blends;
		real_t blend = 0.0;
		bool seeked = false;
		bool is_external_seeking = false;
		Animation::LoopedFlag looped_flag = Animation::LOOPED_FLAG_NONE;
	};

	struct State {
		int track_count = 0;
		HashMap<NodePath, int> track_map;
		List<AnimationState> animation_states;
		bool valid = false;
		AnimationPlayer *player = nullptr;
		AnimationTree *tree = nullptr;
		String invalid_reasons;
		uint64_t last_pass = 0;
	};

	Vector<real_t> blends;
	State *state = nullptr;

	bool is_testing = false;

	double _pre_process(const StringName &p_base_path, AnimationNode *p_parent, State *p_state, double p_time, bool p_seek, bool p_is_external_seeking, const Vector<StringName> &p_connections, bool p_test_only = false);

	//all this is temporary
	StringName base_path;
	Vector<StringName> connections;
	AnimationNode *parent = nullptr;

	HashMap<NodePath, bool> filter;
	bool filter_enabled = false;

	bool closable = false;

	Array _get_filters() const;
	void _set_filters(const Array &p_filters);
	friend class AnimationNodeBlendTree;
	double _blend_node(const StringName &p_subpath, const Vector<StringName> &p_connections, AnimationNode *p_new_parent, Ref<AnimationNode> p_node, double p_time, bool p_seek, bool p_is_external_seeking, real_t p_blend, FilterAction p_filter = FILTER_IGNORE, bool p_sync = true, real_t *r_max = nullptr, bool p_test_only = false);

protected:
	virtual double _process(double p_time, bool p_seek, bool p_is_external_seeking, bool p_test_only = false);
	double process(double p_time, bool p_seek, bool p_is_external_seeking, bool p_test_only = false);

	void blend_animation(const StringName &p_animation, double p_time, double p_delta, bool p_seeked, bool p_is_external_seeking, real_t p_blend, Animation::LoopedFlag p_looped_flag = Animation::LOOPED_FLAG_NONE);
	double blend_node(const StringName &p_sub_path, Ref<AnimationNode> p_node, double p_time, bool p_seek, bool p_is_external_seeking, real_t p_blend, FilterAction p_filter = FILTER_IGNORE, bool p_sync = true, bool p_test_only = false);
	double blend_input(int p_input, double p_time, bool p_seek, bool p_is_external_seeking, real_t p_blend, FilterAction p_filter = FILTER_IGNORE, bool p_sync = true, bool p_test_only = false);

	void make_invalid(const String &p_reason);
	AnimationTree *get_animation_tree() const;

	static void _bind_methods();

	void _validate_property(PropertyInfo &p_property) const;

	GDVIRTUAL0RC(Dictionary, _get_child_nodes)
	GDVIRTUAL0RC(Array, _get_parameter_list)
	GDVIRTUAL1RC(Ref<AnimationNode>, _get_child_by_name, StringName)
	GDVIRTUAL1RC(Variant, _get_parameter_default_value, StringName)
	GDVIRTUAL1RC(bool, _is_parameter_read_only, StringName)
	GDVIRTUAL4RC(double, _process, double, bool, bool, bool)
	GDVIRTUAL0RC(String, _get_caption)
	GDVIRTUAL0RC(bool, _has_filter)

public:
	virtual void get_parameter_list(List<PropertyInfo> *r_list) const;
	virtual Variant get_parameter_default_value(const StringName &p_parameter) const;
	virtual bool is_parameter_read_only(const StringName &p_parameter) const;

	void set_parameter(const StringName &p_name, const Variant &p_value);
	Variant get_parameter(const StringName &p_name) const;

	struct ChildNode {
		StringName name;
		Ref<AnimationNode> node;
	};

	virtual void get_child_nodes(List<ChildNode> *r_child_nodes);

	virtual String get_caption() const;

	virtual bool add_input(const String &p_name);
	virtual void remove_input(int p_index);
	virtual bool set_input_name(int p_input, const String &p_name);
	virtual String get_input_name(int p_input) const;
	int get_input_count() const;
	int find_input(const String &p_name) const;

	void set_filter_path(const NodePath &p_path, bool p_enable);
	bool is_path_filtered(const NodePath &p_path) const;

	void set_filter_enabled(bool p_enable);
	bool is_filter_enabled() const;

	void set_closable(bool p_closable);
	bool is_closable() const;

	virtual bool has_filter() const;

	virtual Ref<AnimationNode> get_child_by_name(const StringName &p_name) const;
	Ref<AnimationNode> find_node_by_path(const String &p_name) const;

	AnimationNode();
};

VARIANT_ENUM_CAST(AnimationNode::FilterAction)

//root node does not allow inputs
class AnimationRootNode : public AnimationNode {
	GDCLASS(AnimationRootNode, AnimationNode);

protected:
	virtual void _tree_changed();
	virtual void _animation_node_renamed(const ObjectID &p_oid, const String &p_old_name, const String &p_new_name);
	virtual void _animation_node_removed(const ObjectID &p_oid, const StringName &p_node);

public:
	AnimationRootNode() {}
};

class AnimationNodeStartState : public AnimationRootNode {
	GDCLASS(AnimationNodeStartState, AnimationRootNode);
};

class AnimationNodeEndState : public AnimationRootNode {
	GDCLASS(AnimationNodeEndState, AnimationRootNode);
};

class AnimationTree : public Node {
	GDCLASS(AnimationTree, Node);

	void _call_object(Object *p_object, const StringName &p_method, const Vector<Variant> &p_params, bool p_deferred);

public:
	enum AnimationProcessCallback {
		ANIMATION_PROCESS_PHYSICS,
		ANIMATION_PROCESS_IDLE,
		ANIMATION_PROCESS_MANUAL,
	};

private:
	struct TrackCache {
		bool root_motion = false;
		uint64_t setup_pass = 0;
		Animation::TrackType type = Animation::TrackType::TYPE_ANIMATION;
		Object *object = nullptr;
		ObjectID object_id;

		TrackCache() {
		}
		virtual ~TrackCache() {}
	};

	struct TrackCacheTransform : public TrackCache {
#ifndef _3D_DISABLED
		Node3D *node_3d = nullptr;
		Skeleton3D *skeleton = nullptr;
#endif // _3D_DISABLED
		int bone_idx = -1;
		bool loc_used = false;
		bool rot_used = false;
		bool scale_used = false;
		Vector3 init_loc = Vector3(0, 0, 0);
		Quaternion init_rot = Quaternion(0, 0, 0, 1);
		Vector3 init_scale = Vector3(1, 1, 1);
		Vector3 loc;
		Quaternion rot;
		Vector3 scale;

		TrackCacheTransform() {
			type = Animation::TYPE_POSITION_3D;
		}
	};

	struct RootMotionCache {
		Vector3 loc = Vector3(0, 0, 0);
		Quaternion rot = Quaternion(0, 0, 0, 1);
		Vector3 scale = Vector3(1, 1, 1);
	};

	struct TrackCacheBlendShape : public TrackCache {
		MeshInstance3D *mesh_3d = nullptr;
		float init_value = 0;
		float value = 0;
		int shape_index = -1;
		TrackCacheBlendShape() { type = Animation::TYPE_BLEND_SHAPE; }
	};

	struct TrackCacheValue : public TrackCache {
		Variant init_value;
		Variant value;
		Vector<StringName> subpath;
		bool is_discrete = false;
		bool is_using_angle = false;
		TrackCacheValue() { type = Animation::TYPE_VALUE; }
	};

	struct TrackCacheMethod : public TrackCache {
		TrackCacheMethod() { type = Animation::TYPE_METHOD; }
	};

	struct TrackCacheBezier : public TrackCache {
		real_t init_value = 0.0;
		real_t value = 0.0;
		Vector<StringName> subpath;
		TrackCacheBezier() {
			type = Animation::TYPE_BEZIER;
		}
	};

	// Audio stream information for each audio stream placed on the track.
	struct PlayingAudioStreamInfo {
		AudioStreamPlaybackPolyphonic::ID index = -1; // ID retrieved from AudioStreamPlaybackPolyphonic.
		double start = 0.0;
		double len = 0.0;
	};

	// Audio track information for mixng and ending.
	struct PlayingAudioTrackInfo {
		HashMap<int, PlayingAudioStreamInfo> stream_info;
		double length = 0.0;
		double time = 0.0;
		real_t volume = 0.0;
		bool loop = false;
		bool backward = false;
		bool use_blend = false;
	};

	struct TrackCacheAudio : public TrackCache {
		Ref<AudioStreamPolyphonic> audio_stream;
		Ref<AudioStreamPlaybackPolyphonic> audio_stream_playback;
		HashMap<ObjectID, PlayingAudioTrackInfo> playing_streams; // Key is Animation resource ObjectID.

		TrackCacheAudio() {
			type = Animation::TYPE_AUDIO;
		}
	};

	struct TrackCacheAnimation : public TrackCache {
		bool playing = false;

		TrackCacheAnimation() {
			type = Animation::TYPE_ANIMATION;
		}
	};

	RootMotionCache root_motion_cache;
	HashMap<NodePath, TrackCache *> track_cache;
	HashSet<TrackCache *> playing_caches;
	Vector<Node *> playing_audio_stream_players;

	Ref<AnimationNode> root;
	NodePath advance_expression_base_node = NodePath(String("."));

	AnimationProcessCallback process_callback = ANIMATION_PROCESS_IDLE;
	bool active = false;
	NodePath animation_player;
	int audio_max_polyphony = 32;

	AnimationNode::State state;
	bool cache_valid = false;
	void _node_removed(Node *p_node);

	void _setup_animation_player();
	void _animation_player_changed();
	void _clear_caches();
	void _clear_playing_caches();
	void _clear_audio_streams();
	bool _update_caches(AnimationPlayer *player);
	void _process_graph(double p_delta);

	uint64_t setup_pass = 1;
	uint64_t process_pass = 1;

	bool started = true;

	NodePath root_motion_track;
	Vector3 root_motion_position = Vector3(0, 0, 0);
	Quaternion root_motion_rotation = Quaternion(0, 0, 0, 1);
	Vector3 root_motion_scale = Vector3(0, 0, 0);
	Vector3 root_motion_position_accumulator = Vector3(0, 0, 0);
	Quaternion root_motion_rotation_accumulator = Quaternion(0, 0, 0, 1);
	Vector3 root_motion_scale_accumulator = Vector3(1, 1, 1);

	friend class AnimationNode;
	bool properties_dirty = true;
	void _tree_changed();
	void _animation_node_renamed(const ObjectID &p_oid, const String &p_old_name, const String &p_new_name);
	void _animation_node_removed(const ObjectID &p_oid, const StringName &p_node);
	void _update_properties();
	List<PropertyInfo> properties;
	HashMap<StringName, HashMap<StringName, StringName>> property_parent_map;
	HashMap<ObjectID, StringName> property_reference_map;
	HashMap<StringName, Pair<Variant, bool>> property_map; // Property value and read-only flag.

	struct Activity {
		uint64_t last_pass = 0;
		real_t activity = 0.0;
	};

	HashMap<StringName, Vector<Activity>> input_activity_map;
	HashMap<StringName, Vector<Activity> *> input_activity_map_get;

	void _update_properties_for_node(const String &p_base_path, Ref<AnimationNode> node);

	ObjectID last_animation_player;

protected:
	bool _set(const StringName &p_name, const Variant &p_value);
	bool _get(const StringName &p_name, Variant &r_ret) const;
	void _get_property_list(List<PropertyInfo> *p_list) const;

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

	GDVIRTUAL5RC(Variant, _post_process_key_value, Ref<Animation>, int, Variant, Object *, int);
	Variant post_process_key_value(const Ref<Animation> &p_anim, int p_track, Variant p_value, const Object *p_object, int p_object_idx = -1);
	virtual Variant _post_process_key_value(const Ref<Animation> &p_anim, int p_track, Variant p_value, const Object *p_object, int p_object_idx = -1);

public:
	void set_tree_root(const Ref<AnimationNode> &p_root);
	Ref<AnimationNode> get_tree_root() const;

	void set_active(bool p_active);
	bool is_active() const;

	void set_process_callback(AnimationProcessCallback p_mode);
	AnimationProcessCallback get_process_callback() const;

	void set_animation_player(const NodePath &p_player);
	NodePath get_animation_player() const;

	void set_advance_expression_base_node(const NodePath &p_advance_expression_base_node);
	NodePath get_advance_expression_base_node() const;

	void set_audio_max_polyphony(int p_audio_max_polyphony);
	int get_audio_max_polyphony() const;

	PackedStringArray get_configuration_warnings() const override;

	bool is_state_invalid() const;
	String get_invalid_state_reason() const;

	void set_root_motion_track(const NodePath &p_track);
	NodePath get_root_motion_track() const;

	Vector3 get_root_motion_position() const;
	Quaternion get_root_motion_rotation() const;
	Vector3 get_root_motion_scale() const;

	Vector3 get_root_motion_position_accumulator() const;
	Quaternion get_root_motion_rotation_accumulator() const;
	Vector3 get_root_motion_scale_accumulator() const;

	real_t get_connection_activity(const StringName &p_path, int p_connection) const;
	void advance(double p_time);

	uint64_t get_last_process_pass() const;
	AnimationTree();
	~AnimationTree();
};

VARIANT_ENUM_CAST(AnimationTree::AnimationProcessCallback)

#endif // ANIMATION_TREE_H