//
// Created by Selim Mustafaev on 11.08.2023.
//

#ifndef NES_CPU_H
#define NES_CPU_H

#include <cstdint>
#include <vector>
#include <memory>

namespace nes {

    class System;

    enum CpuFlags: uint8_t {
        Carry               = (1 << 0),
        Zero                = (1 << 1),
        InterruptDisable    = (1 << 2),
        DecimalMode         = (1 << 3),
        Break               = (1 << 4),
        Unused              = (1 << 5),
        Overflow            = (1 << 6),
        Negative            = (1 << 7)
    };

    class Cpu {
    public:
        struct InstructionArgs {
            uint16_t address;
            uint8_t cycles;
        };

        struct Instruction {
            char name[4];
            void(Cpu::*process)(InstructionArgs);
            InstructionArgs(Cpu::*getAddress)();
            uint8_t cycles;
            bool variableCycles;
        };

        static constexpr uint16_t STACK_BASE = 0x0100;

    public:
        explicit Cpu(System* system);
        void reset();
        bool tick();
        void setFlag(CpuFlags flag, bool value);
        bool getFlag(CpuFlags flag) const;
        void setStartAddress(uint16_t address);
        void nmi();
        
#ifdef NES_LOGGING
        std::string state() const;
#endif

    private:
        size_t _ticks;
        System* _system;
        std::vector<Instruction> _instructions;

    private:
        // Registers
        uint8_t A;      // Accumulator
        uint8_t X;      // - Index registers
        uint8_t Y;      // /

        uint16_t PC;    // Program Counter
        uint8_t SP;     // Stack Pointer
        uint8_t flags;

    private:
        // Debug info
        uint8_t _currentOpcode;

    private:
        void branch(InstructionArgs args);

    private:
        InstructionArgs IMM();
        InstructionArgs ABSL();
        InstructionArgs IMPL();
        InstructionArgs REL();
        InstructionArgs ZP0();
        InstructionArgs IZX();
        InstructionArgs IZY();
        InstructionArgs IND();
        InstructionArgs ABX();
        InstructionArgs ABY();
        InstructionArgs ZPX();
        InstructionArgs ZPY();

    private:
        void LDA(InstructionArgs args);
        void LDX(InstructionArgs args);
        void LDY(InstructionArgs args);
        void STA(InstructionArgs args);
        void STX(InstructionArgs args);
        void CLC(InstructionArgs args);
        void ADC(InstructionArgs args);
        void SBC(InstructionArgs args);
        void DEY(InstructionArgs args);
        void BNE(InstructionArgs args);
        void NOP(InstructionArgs args);
        void SEI(InstructionArgs args);
        void CLD(InstructionArgs args);
        void TXS(InstructionArgs args);
        void BPL(InstructionArgs args);
        void JMP(InstructionArgs args);
        void JSR(InstructionArgs args);
        void SEC(InstructionArgs args);
        void BCS(InstructionArgs args);
        void BCC(InstructionArgs args);
        void BEQ(InstructionArgs args);
        void BIT(InstructionArgs args);
        void BVS(InstructionArgs args);
        void BVC(InstructionArgs args);
        void RTS(InstructionArgs args);
        void SED(InstructionArgs args);
        void PHP(InstructionArgs args);
        void PLA(InstructionArgs args);
        void AND(InstructionArgs args);
        void CMP(InstructionArgs args);
        void BMI(InstructionArgs args);
        void PHA(InstructionArgs args);
        void PLP(InstructionArgs args);
        void ORA(InstructionArgs args);
        void CLV(InstructionArgs args);
        void EOR(InstructionArgs args);
        void CPY(InstructionArgs args);
        void CPX(InstructionArgs args);
        void STY(InstructionArgs args);
        void INY(InstructionArgs args);
        void INX(InstructionArgs args);
        void DEX(InstructionArgs args);
        void TAY(InstructionArgs args);
        void TAX(InstructionArgs args);
        void TYA(InstructionArgs args);
        void TXA(InstructionArgs args);
        void TSX(InstructionArgs args);
        void BRK(InstructionArgs args);
        void RTI(InstructionArgs args);
        void LSR_ACC(InstructionArgs args);
        void LSR(InstructionArgs args);
        void ASL_ACC(InstructionArgs args);
        void ASL(InstructionArgs args);
        void ROR_ACC(InstructionArgs args);
        void ROR(InstructionArgs args);
        void ROL_ACC(InstructionArgs args);
        void ROL(InstructionArgs args);
        void INC(InstructionArgs args);
        void DEC(InstructionArgs args);
    };

}


#endif //NES_CPU_H