/*************************************************************************/
/*  visual_script_expression.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 VISUALSCRIPTEXPRESSION_H
#define VISUALSCRIPTEXPRESSION_H

#include "visual_script.h"
#include "visual_script_builtin_funcs.h"

class VisualScriptExpression : public VisualScriptNode {
	GDCLASS(VisualScriptExpression, VisualScriptNode);
	friend class VisualScriptNodeInstanceExpression;

	struct Input {
		Variant::Type type = Variant::NIL;
		String name;
	};

	Vector<Input> inputs;
	Variant::Type output_type = Variant::NIL;

	String expression;

	bool sequenced = false;
	int str_ofs = 0;
	bool expression_dirty = true;

	bool _compile_expression();

	enum TokenType {
		TK_CURLY_BRACKET_OPEN,
		TK_CURLY_BRACKET_CLOSE,
		TK_BRACKET_OPEN,
		TK_BRACKET_CLOSE,
		TK_PARENTHESIS_OPEN,
		TK_PARENTHESIS_CLOSE,
		TK_IDENTIFIER,
		TK_BUILTIN_FUNC,
		TK_SELF,
		TK_CONSTANT,
		TK_BASIC_TYPE,
		TK_COLON,
		TK_COMMA,
		TK_PERIOD,
		TK_OP_IN,
		TK_OP_EQUAL,
		TK_OP_NOT_EQUAL,
		TK_OP_LESS,
		TK_OP_LESS_EQUAL,
		TK_OP_GREATER,
		TK_OP_GREATER_EQUAL,
		TK_OP_AND,
		TK_OP_OR,
		TK_OP_NOT,
		TK_OP_ADD,
		TK_OP_SUB,
		TK_OP_MUL,
		TK_OP_DIV,
		TK_OP_MOD,
		TK_OP_SHIFT_LEFT,
		TK_OP_SHIFT_RIGHT,
		TK_OP_BIT_AND,
		TK_OP_BIT_OR,
		TK_OP_BIT_XOR,
		TK_OP_BIT_INVERT,
		TK_EOF,
		TK_ERROR,
		TK_MAX
	};

	static const char *token_name[TK_MAX];
	struct Token {
		TokenType type;
		Variant value;
	};

	void _set_error(const String &p_err) {
		if (error_set) {
			return;
		}
		error_str = p_err;
		error_set = true;
	}

	Error _get_token(Token &r_token);

	String error_str;
	bool error_set = true;

	struct ENode {
		enum Type {
			TYPE_INPUT,
			TYPE_CONSTANT,
			TYPE_SELF,
			TYPE_OPERATOR,
			TYPE_INDEX,
			TYPE_NAMED_INDEX,
			TYPE_ARRAY,
			TYPE_DICTIONARY,
			TYPE_CONSTRUCTOR,
			TYPE_BUILTIN_FUNC,
			TYPE_CALL
		};

		ENode *next = nullptr;

		Type type = Type::TYPE_SELF;

		virtual ~ENode() {
			if (next) {
				memdelete(next);
			}
		}
	};

	struct Expression {
		bool is_op = false;
		union {
			Variant::Operator op;
			ENode *node = nullptr;
		};
	};

	ENode *_parse_expression();

	struct InputNode : public ENode {
		int index = 0;
		InputNode() {
			type = TYPE_INPUT;
		}
	};

	struct ConstantNode : public ENode {
		Variant value;
		ConstantNode() {
			type = TYPE_CONSTANT;
		}
	};

	struct OperatorNode : public ENode {
		Variant::Operator op = Variant::Operator::OP_ADD;

		ENode *nodes[2] = { nullptr, nullptr };

		OperatorNode() {
			type = TYPE_OPERATOR;
		}
	};

	struct SelfNode : public ENode {
		SelfNode() {
			type = TYPE_SELF;
		}
	};

	struct IndexNode : public ENode {
		ENode *base = nullptr;
		ENode *index = nullptr;

		IndexNode() {
			type = TYPE_INDEX;
		}
	};

	struct NamedIndexNode : public ENode {
		ENode *base = nullptr;
		StringName name;

		NamedIndexNode() {
			type = TYPE_NAMED_INDEX;
		}
	};

	struct ConstructorNode : public ENode {
		Variant::Type data_type = Variant::Type::NIL;
		Vector<ENode *> arguments;

		ConstructorNode() {
			type = TYPE_CONSTRUCTOR;
		}
	};

	struct CallNode : public ENode {
		ENode *base = nullptr;
		StringName method;
		Vector<ENode *> arguments;

		CallNode() {
			type = TYPE_CALL;
		}
	};

	struct ArrayNode : public ENode {
		Vector<ENode *> array;
		ArrayNode() {
			type = TYPE_ARRAY;
		}
	};

	struct DictionaryNode : public ENode {
		Vector<ENode *> dict;
		DictionaryNode() {
			type = TYPE_DICTIONARY;
		}
	};

	struct BuiltinFuncNode : public ENode {
		VisualScriptBuiltinFunc::BuiltinFunc func = VisualScriptBuiltinFunc::BuiltinFunc::BYTES_TO_VAR;
		Vector<ENode *> arguments;
		BuiltinFuncNode() {
			type = TYPE_BUILTIN_FUNC;
		}
	};

	template <class T>
	T *alloc_node() {
		T *node = memnew(T);
		node->next = nodes;
		nodes = node;
		return node;
	}

	ENode *root = nullptr;
	ENode *nodes = nullptr;

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;

public:
	virtual void reset_state() override;

	virtual int get_output_sequence_port_count() const override;
	virtual bool has_input_sequence_port() const override;

	virtual String get_output_sequence_port_text(int p_port) const override;

	virtual int get_input_value_port_count() const override;
	virtual int get_output_value_port_count() const override;

	virtual PropertyInfo get_input_value_port_info(int p_idx) const override;
	virtual PropertyInfo get_output_value_port_info(int p_idx) const override;

	virtual String get_caption() const override;
	virtual String get_text() const override;
	virtual String get_category() const override { return "operators"; }

	virtual VisualScriptNodeInstance *instantiate(VisualScriptInstance *p_instance) override;

	VisualScriptExpression();
	~VisualScriptExpression();
};

void register_visual_script_expression_node();

#endif // VISUALSCRIPTEXPRESSION_H