/*************************************************************************/
/*  visual_script.h                                                      */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
/*                                                                       */
/* 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 VISUAL_SCRIPT_H
#define VISUAL_SCRIPT_H

#include "core/debugger/engine_debugger.h"
#include "core/debugger/script_debugger.h"
#include "core/doc_data.h"
#include "core/object/script_language.h"
#include "core/os/thread.h"

class VisualScriptInstance;
class VisualScriptNodeInstance;
class VisualScript;

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

	friend class VisualScript;

	Ref<VisualScript> script_used;

	Array default_input_values;
	bool breakpoint = false;

	void _set_default_input_values(Array p_values);
	Array _get_default_input_values() const;

	void validate_input_default_values();

protected:
	void ports_changed_notify();
	static void _bind_methods();

public:
	Ref<VisualScript> get_visual_script() const;

	virtual int get_output_sequence_port_count() const = 0;
	virtual bool has_input_sequence_port() const = 0;

	virtual String get_output_sequence_port_text(int p_port) const = 0;

	virtual bool has_mixed_input_and_sequence_ports() const { return false; }

	virtual int get_input_value_port_count() const = 0;
	virtual int get_output_value_port_count() const = 0;

	virtual PropertyInfo get_input_value_port_info(int p_idx) const = 0;
	virtual PropertyInfo get_output_value_port_info(int p_idx) const = 0;

	void set_default_input_value(int p_port, const Variant &p_value);
	Variant get_default_input_value(int p_port) const;

	virtual String get_caption() const = 0;
	virtual String get_text() const;
	virtual String get_category() const = 0;

	// Used by editor, this is not really saved.
	void set_breakpoint(bool p_breakpoint);
	bool is_breakpoint() const;

	virtual VisualScriptNodeInstance *instantiate(VisualScriptInstance *p_instance) = 0;

	struct TypeGuess {
		Variant::Type type = Variant::NIL;
		StringName gdclass;
		Ref<Script> script;
	};

	virtual TypeGuess guess_output_type(TypeGuess *p_inputs, int p_output) const;

	VisualScriptNode();
};

class VisualScriptNodeInstance {
	friend class VisualScriptInstance;
	friend class VisualScriptLanguage; // For debugger.

	enum { // Input argument addressing.
		INPUT_SHIFT = 1 << 24,
		INPUT_MASK = INPUT_SHIFT - 1,
		INPUT_DEFAULT_VALUE_BIT = INPUT_SHIFT, // from unassigned input port, using default value (edited by user)
	};

	int id = 0;
	int sequence_index = 0;
	VisualScriptNodeInstance **sequence_outputs = nullptr;
	int sequence_output_count = 0;
	Vector<VisualScriptNodeInstance *> dependencies;
	int *input_ports = nullptr;
	int input_port_count = 0;
	int *output_ports = nullptr;
	int output_port_count = 0;
	int working_mem_idx = 0;
	int pass_idx = 0;

	VisualScriptNode *base = nullptr;

public:
	enum StartMode {
		START_MODE_BEGIN_SEQUENCE,
		START_MODE_CONTINUE_SEQUENCE,
		START_MODE_RESUME_YIELD
	};

	enum {
		STEP_SHIFT = 1 << 24,
		STEP_MASK = STEP_SHIFT - 1,
		STEP_FLAG_PUSH_STACK_BIT = STEP_SHIFT, // push bit to stack
		STEP_FLAG_GO_BACK_BIT = STEP_SHIFT << 1, // go back to previous node
		STEP_NO_ADVANCE_BIT = STEP_SHIFT << 2, // do not advance past this node
		STEP_EXIT_FUNCTION_BIT = STEP_SHIFT << 3, // return from function
		STEP_YIELD_BIT = STEP_SHIFT << 4, // yield (will find VisualScriptFunctionState state in first working memory)

		FLOW_STACK_PUSHED_BIT = 1 << 30, // in flow stack, means bit was pushed (must go back here if end of sequence)
		FLOW_STACK_MASK = FLOW_STACK_PUSHED_BIT - 1

	};

	_FORCE_INLINE_ int get_input_port_count() const { return input_port_count; }
	_FORCE_INLINE_ int get_output_port_count() const { return output_port_count; }
	_FORCE_INLINE_ int get_sequence_output_count() const { return sequence_output_count; }

	_FORCE_INLINE_ int get_id() const { return id; }

	virtual int get_working_memory_size() const { return 0; }

	virtual int step(const Variant **p_inputs, Variant **p_outputs, StartMode p_start_mode, Variant *p_working_mem, Callable::CallError &r_error, String &r_error_str) = 0; // Do a step, return which sequence port to go out.

	Ref<VisualScriptNode> get_base_node() { return Ref<VisualScriptNode>(base); }

	VisualScriptNodeInstance();
	virtual ~VisualScriptNodeInstance();
};

class VisualScript : public Script {
	GDCLASS(VisualScript, Script);

	RES_BASE_EXTENSION("vs");

public:
	struct SequenceConnection {
		union {
			struct {
				uint64_t from_node : 24;
				uint64_t from_output : 16;
				uint64_t to_node : 24;
			};
			uint64_t id = 0;
		};

		bool operator<(const SequenceConnection &p_connection) const {
			return id < p_connection.id;
		}
	};

	struct DataConnection {
		union {
			struct {
				uint64_t from_node : 24;
				uint64_t from_port : 8;
				uint64_t to_node : 24;
				uint64_t to_port : 8;
			};
			uint64_t id = 0;
		};

		bool operator<(const DataConnection &p_connection) const {
			return id < p_connection.id;
		}
	};

private:
	friend class VisualScriptInstance;

	StringName base_type;
	struct Argument {
		String name;
		Variant::Type type = Variant::Type::NIL;
	};

	struct NodeData {
		Point2 pos;
		Ref<VisualScriptNode> node;
	};

	HashMap<int, NodeData> nodes; // Can be a sparse map.

	Set<SequenceConnection> sequence_connections;
	Set<DataConnection> data_connections;

	Vector2 scroll;

	struct Function {
		int func_id;
		Function() { func_id = -1; }
	};

	struct Variable {
		PropertyInfo info;
		Variant default_value;
		bool _export = false;
		// Add getter & setter options here.
	};

	HashMap<StringName, Function> functions;
	HashMap<StringName, Variable> variables;
	Map<StringName, Vector<Argument>> custom_signals;
	Vector<Multiplayer::RPCConfig> rpc_functions;

	Map<Object *, VisualScriptInstance *> instances;

	bool is_tool_script;

#ifdef TOOLS_ENABLED
	Set<PlaceHolderScriptInstance *> placeholders;
	// void _update_placeholder(PlaceHolderScriptInstance *p_placeholder);
	virtual void _placeholder_erased(PlaceHolderScriptInstance *p_placeholder) override;
	void _update_placeholders();
#endif

	void _set_variable_info(const StringName &p_name, const Dictionary &p_info);
	Dictionary _get_variable_info(const StringName &p_name) const;

	void _set_data(const Dictionary &p_data);
	Dictionary _get_data() const;

protected:
	void _node_ports_changed(int p_id);
	static void _bind_methods();

public:
	bool inherits_script(const Ref<Script> &p_script) const override;

	void set_scroll(const Vector2 &p_scroll);
	Vector2 get_scroll() const;

	void add_function(const StringName &p_name, int p_func_node_id);
	bool has_function(const StringName &p_name) const;
	void remove_function(const StringName &p_name);
	void rename_function(const StringName &p_name, const StringName &p_new_name);
	void get_function_list(List<StringName> *r_functions) const;
	int get_function_node_id(const StringName &p_name) const;
	void set_tool_enabled(bool p_enabled);

	void add_node(int p_id, const Ref<VisualScriptNode> &p_node, const Point2 &p_pos = Point2());
	void remove_node(int p_id);
	bool has_node(int p_id) const;
	Ref<VisualScriptNode> get_node(int p_id) const;
	void set_node_position(int p_id, const Point2 &p_pos);
	Point2 get_node_position(int p_id) const;
	void get_node_list(List<int> *r_nodes) const;

	void sequence_connect(int p_from_node, int p_from_output, int p_to_node);
	void sequence_disconnect(int p_from_node, int p_from_output, int p_to_node);
	bool has_sequence_connection(int p_from_node, int p_from_output, int p_to_node) const;
	void get_sequence_connection_list(List<SequenceConnection> *r_connection) const;
	Set<int> get_output_sequence_ports_connected(int from_node);

	void data_connect(int p_from_node, int p_from_port, int p_to_node, int p_to_port);
	void data_disconnect(int p_from_node, int p_from_port, int p_to_node, int p_to_port);
	bool has_data_connection(int p_from_node, int p_from_port, int p_to_node, int p_to_port) const;
	void get_data_connection_list(List<DataConnection> *r_connection) const;

	bool is_input_value_port_connected(int p_node, int p_port) const;
	bool get_input_value_port_connection_source(int p_node, int p_port, int *r_node, int *r_port) const;

	void add_variable(const StringName &p_name, const Variant &p_default_value = Variant(), bool p_export = false);
	bool has_variable(const StringName &p_name) const;
	void remove_variable(const StringName &p_name);
	void set_variable_default_value(const StringName &p_name, const Variant &p_value);
	Variant get_variable_default_value(const StringName &p_name) const;
	void set_variable_info(const StringName &p_name, const PropertyInfo &p_info);
	PropertyInfo get_variable_info(const StringName &p_name) const;
	void set_variable_export(const StringName &p_name, bool p_export);
	bool get_variable_export(const StringName &p_name) const;
	void get_variable_list(List<StringName> *r_variables) const;
	void rename_variable(const StringName &p_name, const StringName &p_new_name);

	void add_custom_signal(const StringName &p_name);
	bool has_custom_signal(const StringName &p_name) const;
	void custom_signal_add_argument(const StringName &p_func, Variant::Type p_type, const String &p_name, int p_index = -1);
	void custom_signal_set_argument_type(const StringName &p_func, int p_argidx, Variant::Type p_type);
	Variant::Type custom_signal_get_argument_type(const StringName &p_func, int p_argidx) const;
	void custom_signal_set_argument_name(const StringName &p_func, int p_argidx, const String &p_name);
	String custom_signal_get_argument_name(const StringName &p_func, int p_argidx) const;
	void custom_signal_remove_argument(const StringName &p_func, int p_argidx);
	int custom_signal_get_argument_count(const StringName &p_func) const;
	void custom_signal_swap_argument(const StringName &p_func, int p_argidx, int p_with_argidx);
	void remove_custom_signal(const StringName &p_name);
	void rename_custom_signal(const StringName &p_name, const StringName &p_new_name);
	Set<int> get_output_sequence_ports_connected(const String &edited_func, int from_node);

	void get_custom_signal_list(List<StringName> *r_custom_signals) const;

	int get_available_id() const;

	void set_instance_base_type(const StringName &p_type);

	virtual bool can_instantiate() const override;

	virtual Ref<Script> get_base_script() const override;
	virtual StringName get_instance_base_type() const override;
	virtual ScriptInstance *instance_create(Object *p_this) override;
	virtual bool instance_has(const Object *p_this) const override;

	virtual bool has_source_code() const override;
	virtual String get_source_code() const override;
	virtual void set_source_code(const String &p_code) override;
	virtual Error reload(bool p_keep_state = false) override;

#ifdef TOOLS_ENABLED
	virtual const Vector<DocData::ClassDoc> &get_documentation() const override {
		static Vector<DocData::ClassDoc> docs;
		return docs;
	}
#endif // TOOLS_ENABLED

	virtual bool is_tool() const override;
	virtual bool is_valid() const override;

	virtual ScriptLanguage *get_language() const override;

	virtual bool has_script_signal(const StringName &p_signal) const override;
	virtual void get_script_signal_list(List<MethodInfo> *r_signals) const override;

	virtual bool get_property_default_value(const StringName &p_property, Variant &r_value) const override;
	virtual void get_script_method_list(List<MethodInfo> *p_list) const override;

	virtual bool has_method(const StringName &p_method) const override;
	virtual MethodInfo get_method_info(const StringName &p_method) const override;

	virtual void get_script_property_list(List<PropertyInfo> *p_list) const override;

	virtual int get_member_line(const StringName &p_member) const override;

	virtual const Vector<Multiplayer::RPCConfig> get_rpc_methods() const override;

#ifdef TOOLS_ENABLED
	virtual bool are_subnodes_edited() const;
#endif

	VisualScript();
	~VisualScript();
};

class VisualScriptInstance : public ScriptInstance {
	Object *owner = nullptr;
	Ref<VisualScript> script;

	Map<StringName, Variant> variables; // Using variable path, not script.
	Map<int, VisualScriptNodeInstance *> instances;

	struct Function {
		int node = 0;
		int max_stack = 0;
		int trash_pos = 0;
		int flow_stack_size = 0;
		int pass_stack_size = 0;
		int node_count = 0;
		int argument_count = 0;
	};

	Map<StringName, Function> functions;

	Vector<Variant> default_values;
	int max_input_args = 0;
	int max_output_args = 0;

	StringName source;

	void _dependency_step(VisualScriptNodeInstance *node, int p_pass, int *pass_stack, const Variant **input_args, Variant **output_args, Variant *variant_stack, Callable::CallError &r_error, String &error_str, VisualScriptNodeInstance **r_error_node);
	Variant _call_internal(const StringName &p_method, void *p_stack, int p_stack_size, VisualScriptNodeInstance *p_node, int p_flow_stack_pos, int p_pass, bool p_resuming_yield, Callable::CallError &r_error);

	friend class VisualScriptFunctionState; // For yield.
	friend class VisualScriptLanguage; // For debugger.
public:
	virtual bool set(const StringName &p_name, const Variant &p_value);
	virtual bool get(const StringName &p_name, Variant &r_ret) const;
	virtual void get_property_list(List<PropertyInfo> *p_properties) const;
	virtual Variant::Type get_property_type(const StringName &p_name, bool *r_is_valid = nullptr) const;

	virtual void get_method_list(List<MethodInfo> *p_list) const;
	virtual bool has_method(const StringName &p_method) const;
	virtual Variant call(const StringName &p_method, const Variant **p_args, int p_argcount, Callable::CallError &r_error);
	virtual void notification(int p_notification);
	String to_string(bool *r_valid);

	bool set_variable(const StringName &p_variable, const Variant &p_value) {
		Map<StringName, Variant>::Element *E = variables.find(p_variable);
		if (!E) {
			return false;
		}

		E->get() = p_value;
		return true;
	}

	bool get_variable(const StringName &p_variable, Variant *r_variable) const {
		const Map<StringName, Variant>::Element *E = variables.find(p_variable);
		if (!E) {
			return false;
		}

		*r_variable = E->get();
		return true;
	}

	virtual Ref<Script> get_script() const;

	_FORCE_INLINE_ VisualScript *get_script_ptr() { return script.ptr(); }
	_FORCE_INLINE_ Object *get_owner_ptr() { return owner; }

	void create(const Ref<VisualScript> &p_script, Object *p_owner);

	virtual ScriptLanguage *get_language();

	virtual const Vector<Multiplayer::RPCConfig> get_rpc_methods() const;

	VisualScriptInstance();
	~VisualScriptInstance();
};

class VisualScriptFunctionState : public RefCounted {
	GDCLASS(VisualScriptFunctionState, RefCounted);
	friend class VisualScriptInstance;

	ObjectID instance_id;
	ObjectID script_id;
	VisualScriptInstance *instance = nullptr;
	StringName function;
	Vector<uint8_t> stack;
	int working_mem_index = 0;
	int variant_stack_size = 0;
	VisualScriptNodeInstance *node = nullptr;
	int flow_stack_pos = 0;
	int pass = 0;

	Variant _signal_callback(const Variant **p_args, int p_argcount, Callable::CallError &r_error);

protected:
	static void _bind_methods();

public:
	void connect_to_signal(Object *p_obj, const String &p_signal, Array p_binds);
	bool is_valid() const;
	Variant resume(Array p_args);
	VisualScriptFunctionState();
	~VisualScriptFunctionState();
};

typedef Ref<VisualScriptNode> (*VisualScriptNodeRegisterFunc)(const String &p_type);

class VisualScriptLanguage : public ScriptLanguage {
	Map<String, VisualScriptNodeRegisterFunc> register_funcs;

	struct CallLevel {
		Variant *stack = nullptr;
		Variant **work_mem = nullptr;
		const StringName *function = nullptr;
		VisualScriptInstance *instance = nullptr;
		int *current_id = nullptr;
	};

	int _debug_parse_err_node = -1;
	String _debug_parse_err_file = "";
	String _debug_error;
	int _debug_call_stack_pos = 0;
	int _debug_max_call_stack;
	CallLevel *_call_stack;

public:
	StringName notification = "_notification";
	StringName _get_output_port_unsequenced;
	StringName _step = "_step";
	StringName _subcall = "_subcall";

	static VisualScriptLanguage *singleton;

	Mutex lock;

	bool debug_break(const String &p_error, bool p_allow_continue = true);
	bool debug_break_parse(const String &p_file, int p_node, const String &p_error);

	_FORCE_INLINE_ void enter_function(VisualScriptInstance *p_instance, const StringName *p_function, Variant *p_stack, Variant **p_work_mem, int *current_id) {
		if (Thread::get_main_id() != Thread::get_caller_id()) {
			return; // No support for other threads than main for now.
		}

		if (EngineDebugger::get_script_debugger()->get_lines_left() > 0 && EngineDebugger::get_script_debugger()->get_depth() >= 0) {
			EngineDebugger::get_script_debugger()->set_depth(EngineDebugger::get_script_debugger()->get_depth() + 1);
		}

		if (_debug_call_stack_pos >= _debug_max_call_stack) {
			// Stack overflow.
			_debug_error = "Stack Overflow (Stack Size: " + itos(_debug_max_call_stack) + ")";
			EngineDebugger::get_script_debugger()->debug(this);
			return;
		}

		_call_stack[_debug_call_stack_pos].stack = p_stack;
		_call_stack[_debug_call_stack_pos].instance = p_instance;
		_call_stack[_debug_call_stack_pos].function = p_function;
		_call_stack[_debug_call_stack_pos].work_mem = p_work_mem;
		_call_stack[_debug_call_stack_pos].current_id = current_id;
		_debug_call_stack_pos++;
	}

	_FORCE_INLINE_ void exit_function() {
		if (Thread::get_main_id() != Thread::get_caller_id()) {
			return; // No support for other threads than main for now.
		}

		if (EngineDebugger::get_script_debugger()->get_lines_left() > 0 && EngineDebugger::get_script_debugger()->get_depth() >= 0) {
			EngineDebugger::get_script_debugger()->set_depth(EngineDebugger::get_script_debugger()->get_depth() - 1);
		}

		if (_debug_call_stack_pos == 0) {
			_debug_error = "Stack Underflow (Engine Bug)";
			EngineDebugger::get_script_debugger()->debug(this);
			return;
		}

		_debug_call_stack_pos--;
	}

	//////////////////////////////////////

	virtual String get_name() const;

	/* LANGUAGE FUNCTIONS */
	virtual void init();
	virtual String get_type() const;
	virtual String get_extension() const;
	virtual Error execute_file(const String &p_path);
	virtual void finish();

	/* EDITOR FUNCTIONS */
	virtual void get_reserved_words(List<String> *p_words) const;
	virtual bool is_control_flow_keyword(String p_keyword) const;
	virtual void get_comment_delimiters(List<String> *p_delimiters) const;
	virtual void get_string_delimiters(List<String> *p_delimiters) const;
	virtual Ref<Script> get_template(const String &p_class_name, const String &p_base_class_name) const;
	virtual bool is_using_templates();
	virtual void make_template(const String &p_class_name, const String &p_base_class_name, Ref<Script> &p_script);
	virtual bool validate(const String &p_script, const String &p_path = "", List<String> *r_functions = nullptr, List<ScriptLanguage::ScriptError> *r_errors = nullptr, List<ScriptLanguage::Warning> *r_warnings = nullptr, Set<int> *r_safe_lines = nullptr) const;
	virtual Script *create_script() const;
	virtual bool has_named_classes() const;
	virtual bool supports_builtin_mode() const;
	virtual int find_function(const String &p_function, const String &p_code) const;
	virtual String make_function(const String &p_class, const String &p_name, const PackedStringArray &p_args) const;
	virtual void auto_indent_code(String &p_code, int p_from_line, int p_to_line) const;
	virtual void add_global_constant(const StringName &p_variable, const Variant &p_value);

	/* DEBUGGER FUNCTIONS */

	virtual String debug_get_error() const;
	virtual int debug_get_stack_level_count() const;
	virtual int debug_get_stack_level_line(int p_level) const;
	virtual String debug_get_stack_level_function(int p_level) const;
	virtual String debug_get_stack_level_source(int p_level) const;
	virtual void debug_get_stack_level_locals(int p_level, List<String> *p_locals, List<Variant> *p_values, int p_max_subitems = -1, int p_max_depth = -1);
	virtual void debug_get_stack_level_members(int p_level, List<String> *p_members, List<Variant> *p_values, int p_max_subitems = -1, int p_max_depth = -1);
	virtual void debug_get_globals(List<String> *p_locals, List<Variant> *p_values, int p_max_subitems = -1, int p_max_depth = -1);
	virtual String debug_parse_stack_level_expression(int p_level, const String &p_expression, int p_max_subitems = -1, int p_max_depth = -1);

	virtual void reload_all_scripts();
	virtual void reload_tool_script(const Ref<Script> &p_script, bool p_soft_reload);
	/* LOADER FUNCTIONS */

	virtual void get_recognized_extensions(List<String> *p_extensions) const;
	virtual void get_public_functions(List<MethodInfo> *p_functions) const;
	virtual void get_public_constants(List<Pair<String, Variant>> *p_constants) const;

	virtual void profiling_start();
	virtual void profiling_stop();

	virtual int profiling_get_accumulated_data(ProfilingInfo *p_info_arr, int p_info_max);
	virtual int profiling_get_frame_data(ProfilingInfo *p_info_arr, int p_info_max);

	void add_register_func(const String &p_name, VisualScriptNodeRegisterFunc p_func);
	void remove_register_func(const String &p_name);
	Ref<VisualScriptNode> create_node_from_name(const String &p_name);
	void get_registered_node_names(List<String> *r_names);

	VisualScriptLanguage();
	~VisualScriptLanguage();
};

// Aid for registering.
template <class T>
static Ref<VisualScriptNode> create_node_generic(const String &p_name) {
	Ref<T> node;
	node.instantiate();
	return node;
}

#endif // VISUAL_SCRIPT_H