/* SPDX-License-Identifier: MIT */

#ifndef RGBDS_ASM_RPN_H
#define RGBDS_ASM_RPN_H

#include <stdint.h>
#include <string>
#include <vector>

#include "linkdefs.hpp"

struct Symbol;

struct Expression {
	int32_t val = 0;       // If the expression's value is known, it's here
	std::string reason{};  // Why the expression is not known, if it isn't
	bool isKnown = true;   // Whether the expression's value is known at assembly time
	bool isSymbol = false; // Whether the expression represents a symbol suitable for const diffing
	std::vector<uint8_t> rpn{}; // Bytes serializing the RPN expression
	uint32_t rpnPatchSize = 0;  // Size the expression will take in the object file

	Expression() = default;
	Expression(Expression &&) = default;
#ifdef _MSC_VER
	// MSVC and WinFlexBison won't build without this...
	Expression(Expression const &) = default;
#endif

	Expression &operator=(Expression &&) = default;

	int32_t getConstVal() const;
	Symbol const *symbolOf() const;
	bool isDiffConstant(Symbol const *symName) const;

	void makeNumber(uint32_t value);
	void makeSymbol(std::string const &symName);
	void makeBankSymbol(std::string const &symName);
	void makeBankSection(std::string const &sectName);
	void makeSizeOfSection(std::string const &sectName);
	void makeStartOfSection(std::string const &sectName);
	void makeSizeOfSectionType(SectionType type);
	void makeStartOfSectionType(SectionType type);
	void makeHigh();
	void makeLow();
	void makeNeg();
	void makeNot();
	void makeLogicNot();
	void makeBinaryOp(RPNCommand op, Expression &&src1, Expression const &src2);

	void makeCheckHRAM();
	void makeCheckRST();

	void checkNBit(uint8_t n) const;

private:
	void clear();
	uint8_t *reserveSpace(uint32_t size);
	uint8_t *reserveSpace(uint32_t size, uint32_t patchSize);

	// Makes an expression "not known", also setting its error message
	template<typename... Ts>
	void makeUnknown(Ts... parts) {
		isKnown = false;
		reason.clear();
		(reason.append(parts), ...);
	}
};

#endif // RGBDS_ASM_RPN_H