#pragma once

#include <cstdint>
#include <string>
#include <array>
#include <functional>

#include "Memory.h"
#include "Processor.h"
#include "ProcessorType.h"
#include "AddressingMode.h"
#include "Signal.h"

namespace EightBit {
	class MOS6502 : public Processor {
	public:
		enum StatusBits {
			NF = 0x80,	// Negative
			VF = 0x40,  // Overflow
			RF = 0x20,  // reserved
			BF = 0x10,  // Brk
			DF = 0x08,	// D (use BCD for arithmetic)
			IF = 0x04,	// I (IRQ disable)
			ZF = 0x02,	// Zero
			CF = 0x01,	// Carry
		};

		typedef std::function<void()> instruction_t;

		struct Instruction {
			instruction_t vector = nullptr;
			int count = 0;
			AddressingMode mode = AddressingMode::Illegal;
			std::string display = "";
		};

		MOS6502(Memory& memory, ProcessorType level);

		Signal<MOS6502> ExecutingInstruction;
		Signal<MOS6502> ExecutedInstruction;

		ProcessorType getLevel() const { return level; }

		uint8_t& X() { return x; }
		uint8_t& Y() { return y; }
		uint8_t& A() { return a; }
		uint8_t& S() { return s; }
		uint8_t& P() { return p; }

		const Instruction& getInstruction(uint8_t code) const {
			return instructions[code];
		}

		virtual void initialise();

		virtual int step();

		virtual void Reset();

		virtual void TriggerIRQ();
		virtual void TriggerNMI();

		void GetWord(register16_t& output);
		void GetWord(uint16_t offset, register16_t& output);

		uint8_t GetByte() { return m_memory.read(); }
		uint8_t GetByte(uint16_t offset) { return m_memory.read(offset); }

		void SetByte(uint8_t value) { m_memory.write(value); }
		void SetByte(uint16_t offset, uint8_t value) { m_memory.write(offset, value); }

	protected:
		virtual void Interrupt(uint16_t vector);

		virtual int Execute(uint8_t cell);

		void ___();

	private:
		static Instruction INS(instruction_t method, int cycles, AddressingMode addressing, std::string display);

		void Install6502Instructions();
		void Install65sc02Instructions();
		void Install65c02Instructions();

		void InstallInstructionSet(const std::array<Instruction, 0x100>& basis);
		void OverlayInstructionSet(const std::array<Instruction, 0x100>& overlay);
		void OverlayInstructionSet(const std::array<Instruction, 0x100>& overlay, bool includeIllegal);

		void UpdateZeroFlag(uint8_t datum) { clearFlag(P(), ZF, datum); }
		void UpdateNegativeFlag(uint8_t datum) { setFlag(P(), NF, datum & NF); }
		
		void UpdateZeroNegativeFlags(uint8_t datum) {
			UpdateZeroFlag(datum);
			UpdateNegativeFlag(datum);
		}

		void PushByte(uint8_t value);
		uint8_t PopByte();
		void PushWord(register16_t value);
		void PopWord(register16_t& output);

		uint8_t FetchByte();
		void FetchWord(register16_t& output);

#pragma region 6502 addressing modes

#pragma region Addresses

		void Address_Absolute() {
			FetchWord(m_memptr);
		}

		void Address_ZeroPage() {
			m_memptr.low = FetchByte();
			m_memptr.high = 0;
		}

		void Address_ZeroPageIndirect() {
			Address_ZeroPage();
			m_memory.ADDRESS() = m_memptr;
			GetWord(m_memptr);
		}

		void Address_Indirect() {
			Address_Absolute();
			m_memory.ADDRESS() = m_memptr;
			GetWord(m_memptr);
		}

		void Address_IndirectX() {
			Address_Absolute();
			m_memory.ADDRESS().word = m_memptr.word + X();
			GetWord(m_memptr);
		}

		void Address_ZeroPageX() {
			Address_ZeroPage();
			m_memptr.low += X();
		}

		void Address_ZeroPageY() {
			Address_ZeroPage();
			m_memptr.low += Y();
		}

		void Address_AbsoluteX() {
			Address_Absolute();
			m_memptr.word += X();
		}

		void Address_AbsoluteY() {
			Address_Absolute();
			m_memptr.word += Y();
		}

		void Address_IndexedIndirectX() {
			Address_ZeroPageX();
			m_memory.ADDRESS() = m_memptr;
			GetWord(m_memptr);
		}

		void Address_IndirectIndexedY() {
			Address_ZeroPageIndirect();
			m_memptr.word += Y();
		}

#pragma endregion Addresses

#pragma region References

		uint8_t& AM_A() {
			return A();
		}

		uint8_t& AM_X() {
			return X();
		}

		uint8_t& AM_Y() {
			return Y();
		}

		uint8_t& AM_Immediate() {
			FetchByte();
			return m_memory.reference();
		}

		uint8_t& AM_Absolute() {
			Address_Absolute();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

		uint8_t& AM_ZeroPage() {
			Address_ZeroPage();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

		uint8_t& AM_ZeroPageIndirect() {
			Address_ZeroPageIndirect();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

		uint8_t& AM_AbsoluteX() {
			Address_AbsoluteX();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

		uint8_t& AM_AbsoluteY() {
			Address_AbsoluteY();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

		uint8_t& AM_ZeroPageX() {
			Address_ZeroPageX();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

		uint8_t& AM_ZeroPageY() {
			Address_ZeroPageY();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

		uint8_t& AM_IndexedIndirectX() {
			Address_IndexedIndirectX();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

		uint8_t& AM_IndirectIndexedY() {
			Address_IndirectIndexedY();
			m_memory.ADDRESS() = m_memptr;
			return m_memory.reference();
		}

#pragma endregion References

#pragma endregion 6502 addressing modes

		void DEC(uint8_t& output);

		void ROR(uint8_t& output);

		void LSR(uint8_t& output);

		void BIT(uint8_t data);

		void TSB(uint8_t& output);
		void TRB(uint8_t& output);

		void INC(uint8_t& output);

		void ROL(uint8_t& output);

		void ASL(uint8_t& output);

		void ORA(uint8_t data);

		void AND(uint8_t data);

		void SBC(uint8_t data);
		void SBC_b(uint8_t data);
		void SBC_d(uint8_t data);

		void EOR(uint8_t data);

		void CPX(uint8_t data);
		void CPY(uint8_t data);
		void CMP(uint8_t data);
		void CMP(uint8_t first, uint8_t second);

		void LDA(uint8_t data);
		void LDY(uint8_t data);
		void LDX(uint8_t data);

		void ADC(uint8_t data);
		void ADC_b(uint8_t data);
		void ADC_d(uint8_t data);

		void RMB(uint8_t& output, uint8_t flag);
		void SMB(uint8_t& output, uint8_t flag);

		void Branch(int8_t displacement);
		void Branch();
		void Branch(bool flag);
		void BitBranch_Clear(uint8_t check);
		void BitBranch_Set(uint8_t check);

		void NOP_imp();
		void NOP2_imp();
		void NOP3_imp();

		void ORA_xind();
		void ORA_zp();
		void ORA_imm();
		void ORA_abs();
		void ORA_absx();
		void ORA_absy();
		void ORA_zpx();
		void ORA_indy();
		void ORA_zpind();

		void AND_zpx();
		void AND_indy();
		void AND_zp();
		void AND_absx();
		void AND_absy();
		void AND_imm();
		void AND_xind();
		void AND_abs();
		void AND_zpind();

		void EOR_absx();
		void EOR_absy();
		void EOR_zpx();
		void EOR_indy();
		void EOR_abs();
		void EOR_imm();
		void EOR_zp();
		void EOR_xind();
		void EOR_zpind();

		void LDA_absx();
		void LDA_absy();
		void LDA_zpx();
		void LDA_indy();
		void LDA_abs();
		void LDA_imm();
		void LDA_zp();
		void LDA_xind();
		void LDA_zpind();

		void LDX_imm();
		void LDX_zp();
		void LDX_abs();
		void LDX_zpy();
		void LDX_absy();

		void LDY_imm();
		void LDY_zp();
		void LDY_abs();
		void LDY_zpx();
		void LDY_absx();

		void CMP_absx();
		void CMP_absy();
		void CMP_zpx();
		void CMP_indy();
		void CMP_abs();
		void CMP_imm();
		void CMP_zp();
		void CMP_xind();
		void CMP_zpind();

		void CPX_abs();
		void CPX_zp();
		void CPX_imm();

		void CPY_imm();
		void CPY_zp();
		void CPY_abs();

		void ADC_zp();
		void ADC_xind();
		void ADC_imm();
		void ADC_abs();
		void ADC_zpx();
		void ADC_indy();
		void ADC_absx();
		void ADC_absy();
		void ADC_zpind();

		void SBC_xind();
		void SBC_zp();
		void SBC_imm();
		void SBC_abs();
		void SBC_zpx();
		void SBC_indy();
		void SBC_absx();
		void SBC_absy();
		void SBC_zpind();

		void BIT_imm();
		void BIT_zp();
		void BIT_zpx();
		void BIT_abs();
		void BIT_absx();

		void DEC_a();
		void DEC_absx();
		void DEC_zpx();
		void DEC_abs();
		void DEC_zp();

		void DEX_imp();
		void DEY_imp();

		void INC_a();
		void INC_zp();
		void INC_absx();
		void INC_zpx();
		void INC_abs();

		void INX_imp();
		void INY_imp();

		void STX_zpy();
		void STX_abs();
		void STX_zp();

		void STY_zpx();
		void STY_abs();
		void STY_zp();

		void STA_absx();
		void STA_absy();
		void STA_zpx();
		void STA_indy();
		void STA_abs();
		void STA_zp();
		void STA_xind();
		void STA_zpind();

		void STZ_zp();
		void STZ_zpx();
		void STZ_abs();
		void STZ_absx();

		void TSX_imp();
		void TAX_imp();
		void TAY_imp();
		void TXS_imp();
		void TYA_imp();
		void TXA_imp();

		void PHP_imp();
		void PLP_imp();
		void PLA_imp();
		void PHA_imp();
		void PHX_imp();
		void PHY_imp();
		void PLX_imp();
		void PLY_imp();

		void ASL_a();
		void ASL_zp();
		void ASL_abs();
		void ASL_absx();
		void ASL_zpx();

		void LSR_absx();
		void LSR_zpx();
		void LSR_abs();
		void LSR_a();
		void LSR_zp();

		void ROL_absx();
		void ROL_zpx();
		void ROL_abs();
		void ROL_a();
		void ROL_zp();

		void ROR_absx();
		void ROR_zpx();
		void ROR_abs();
		void ROR_a();
		void ROR_zp();

		void TSB_zp();
		void TSB_abs();

		void TRB_zp();
		void TRB_abs();

		void RMB0_zp();
		void RMB1_zp();
		void RMB2_zp();
		void RMB3_zp();
		void RMB4_zp();
		void RMB5_zp();
		void RMB6_zp();
		void RMB7_zp();

		void SMB0_zp();
		void SMB1_zp();
		void SMB2_zp();
		void SMB3_zp();
		void SMB4_zp();
		void SMB5_zp();
		void SMB6_zp();
		void SMB7_zp();

		void JSR_abs();
		void RTI_imp();
		void RTS_imp();
		void JMP_abs();
		void JMP_ind();
		void JMP_absxind();
		void BRK_imp();

		void WAI_imp();
		void STP_imp();

		void SED_imp();
		void CLD_imp();
		void CLV_imp();
		void SEI_imp();
		void CLI_imp();
		void CLC_imp();
		void SEC_imp();

		void BMI_rel();
		void BPL_rel();
		void BVC_rel();
		void BVS_rel();
		void BCC_rel();
		void BCS_rel();
		void BNE_rel();
		void BEQ_rel();
		void BRA_rel();

		void BBR0_zprel();
		void BBR1_zprel();
		void BBR2_zprel();
		void BBR3_zprel();
		void BBR4_zprel();
		void BBR5_zprel();
		void BBR6_zprel();
		void BBR7_zprel();

		void BBS0_zprel();
		void BBS1_zprel();
		void BBS2_zprel();
		void BBS3_zprel();
		void BBS4_zprel();
		void BBS5_zprel();
		void BBS6_zprel();
		void BBS7_zprel();

		const uint16_t PageOne = 0x100;
		const uint16_t IRQvector = 0xfffe;
		const uint16_t RSTvector = 0xfffc;
		const uint16_t NMIvector = 0xfffa;

		uint8_t x;		// index register X
		uint8_t y;		// index register Y
		uint8_t a;		// accumulator
		uint8_t s;		// stack pointer
		uint8_t p;		// processor status

		register16_t m_memptr;

		std::array<Instruction, 0x100> instructions;

		ProcessorType level;

		std::array<Instruction, 0x100> overlay6502;
		std::array<Instruction, 0x100> overlay65sc02;
		std::array<Instruction, 0x100> overlay65c02;
	};
}