#ifndef YMF262_HH
#define YMF262_HH

#include "ResampledSoundDevice.hh"

#include "EmuTimer.hh"

#include "EmuTime.hh"
#include "FixedPoint.hh"
#include "IRQHelper.hh"
#include "SimpleDebuggable.hh"
#include "serialize_meta.hh"

#include <array>
#include <cstdint>
#include <memory>
#include <span>
#include <string>

namespace openmsx {

class DeviceConfig;

class YMF262 final : private ResampledSoundDevice, private EmuTimerCallback
{
public:
	// sin-wave entries
	static constexpr int SIN_BITS = 10;
	static constexpr int SIN_LEN  = 1 << SIN_BITS;
	static constexpr int SIN_MASK = SIN_LEN - 1;

public:
	YMF262(const std::string& name, const DeviceConfig& config,
	       bool isYMF278);
	~YMF262();

	void reset(EmuTime time);
	void writeReg   (unsigned r, uint8_t v, EmuTime time);
	void writeReg512(unsigned r, uint8_t v, EmuTime time);
	[[nodiscard]] uint8_t readReg(unsigned reg) const;
	[[nodiscard]] uint8_t peekReg(unsigned reg) const;
	[[nodiscard]] uint8_t readStatus();
	[[nodiscard]] uint8_t peekStatus() const;

	void setMixLevel(uint8_t x, EmuTime time);

	template<typename Archive>
	void serialize(Archive& ar, unsigned version);

public:
	/** 16.16 fixed point type for frequency calculations */
	using FreqIndex = FixedPoint<16>;

	enum class EnvelopeState : uint8_t {
		ATTACK, DECAY, SUSTAIN, RELEASE, OFF
	};

private:
	class Channel;

	class Slot {
	public:
		Slot();
		[[nodiscard]] int op_calc(unsigned phase, unsigned lfo_am) const;
		void FM_KEYON(uint8_t key_set);
		void FM_KEYOFF(uint8_t key_clr);
		void advanceEnvelopeGenerator(unsigned egCnt);
		void advancePhaseGenerator(const Channel& ch, unsigned lfo_pm);
		void update_ar_dr();
		void update_rr();
		void calc_fc(const Channel& ch);

		/** Sets the amount of feedback [0..7]
		 */
		void setFeedbackShift(uint8_t value) {
			fb_shift = value ? 9 - value : 0;
		}

		template<typename Archive>
		void serialize(Archive& ar, unsigned version);

		// Phase Generator
		FreqIndex Cnt{0};  // frequency counter
		FreqIndex Incr{0}; // frequency counter step
		int* connect{nullptr}; // slot output pointer
		std::array<int, 2> op1_out{0, 0}; // slot1 output for feedback

		// Envelope Generator
		unsigned TL{0};  // total level: TL << 2
		unsigned TLL{0}; // adjusted now TL
		int volume{0};   // envelope counter
		int sl{0};       // sustain level: sl_tab[SL]

		std::span<const unsigned, SIN_LEN> waveTable; // waveform select

		EnvelopeState state{EnvelopeState::OFF}; // EG: phase type
		unsigned eg_m_ar{0};  // (attack state)
		unsigned eg_m_dr{0};  // (decay state)
		unsigned eg_m_rr{0};  // (release state)
		uint8_t eg_sh_ar{0};  // (attack state)
		uint8_t eg_sel_ar{0}; // (attack state)
		uint8_t eg_sh_dr{0};  // (decay state)
		uint8_t eg_sel_dr{0}; // (decay state)
		uint8_t eg_sh_rr{0};  // (release state)
		uint8_t eg_sel_rr{0}; // (release state)

		uint8_t key{0}; // 0 = KEY OFF, >0 = KEY ON

		uint8_t fb_shift{0}; // PG: feedback shift value
		bool CON{false};     // PG: connection (algorithm) type
		bool eg_type{false}; // EG: percussive/non-percussive mode

		// LFO
		uint8_t AMmask{0}; // LFO Amplitude Modulation enable mask
		bool vib{false};   // LFO Phase Modulation enable flag (active high)

		uint8_t ar{0};	// attack rate: AR<<2
		uint8_t dr{0};	// decay rate:  DR<<2
		uint8_t rr{0};	// release rate:RR<<2
		uint8_t KSR{0};	// key scale rate
		uint8_t ksl{0};	// key scale level
		uint8_t ksr{0};	// key scale rate: kcode>>KSR
		uint8_t mul{0};	// multiple: mul_tab[ML]
	};

	class Channel {
	public:
		void chan_calc(unsigned lfo_am);
		void chan_calc_ext(unsigned lfo_am);

		template<typename Archive>
		void serialize(Archive& ar, unsigned version);

		std::array<Slot, 2> slot;

		int block_fnum{0};    // block+fnum
		FreqIndex fc{0};      // Freq. Increment base
		unsigned ksl_base{0}; // KeyScaleLevel Base step
		uint8_t kcode{0};     // key code (for key scaling)

		// there are 12 2-operator channels which can be combined in pairs
		// to form six 4-operator channel, they are:
		//  0 and 3,
		//  1 and 4,
		//  2 and 5,
		//  9 and 12,
		//  10 and 13,
		//  11 and 14
		bool extended{false}; // set if this channel forms up a 4op channel with
		                      // another channel (only used by first of pair of
		                      // channels, ie 0,1,2 and 9,10,11)
	};

	// SoundDevice
	[[nodiscard]] float getAmplificationFactorImpl() const override;
	void generateChannels(std::span<float*> bufs, unsigned num) override;

	void callback(uint8_t flag) override;

	void writeRegDirect(unsigned r, uint8_t v, EmuTime time);
	void init_tables();
	void setStatus(uint8_t flag);
	void resetStatus(uint8_t flag);
	void changeStatusMask(uint8_t flag);
	void advance();

	[[nodiscard]] unsigned genPhaseHighHat();
	[[nodiscard]] unsigned genPhaseSnare();
	[[nodiscard]] unsigned genPhaseCymbal();

	void chan_calc_rhythm(unsigned lfo_am);
	void set_mul(unsigned sl, uint8_t v);
	void set_ksl_tl(unsigned sl, uint8_t v);
	void set_ar_dr(unsigned sl, uint8_t v);
	void set_sl_rr(unsigned sl, uint8_t v);
	[[nodiscard]] bool checkMuteHelper() const;

	[[nodiscard]] bool isExtended(unsigned ch) const;
	[[nodiscard]] Channel& getFirstOfPair(unsigned ch);
	[[nodiscard]] Channel& getSecondOfPair(unsigned ch);

	struct Debuggable final : SimpleDebuggable {
		Debuggable(MSXMotherBoard& motherBoard, const std::string& name);
		[[nodiscard]] uint8_t read(unsigned address) override;
		void write(unsigned address, uint8_t value, EmuTime time) override;
	} debuggable;

	// Bitmask for register 0x04
	static constexpr int R04_ST1       = 0x01; // Timer1 Start
	static constexpr int R04_ST2       = 0x02; // Timer2 Start
	static constexpr int R04_MASK_T2   = 0x20; // Mask Timer2 flag
	static constexpr int R04_MASK_T1   = 0x40; // Mask Timer1 flag
	static constexpr int R04_IRQ_RESET = 0x80; // IRQ RESET

	// Bitmask for status register
	static constexpr int STATUS_T2      = R04_MASK_T2;
	static constexpr int STATUS_T1      = R04_MASK_T1;
	// Timers (see EmuTimer class for details about timing)
	const std::unique_ptr<EmuTimer> timer1; //  80.8us OPL4  ( 80.5us OPL3)
	const std::unique_ptr<EmuTimer> timer2; // 323.1us OPL4  (321.8us OPL3)

	IRQHelper irq;

	std::array<int, 18> chanOut = {};      // 18 channels

	std::array<uint8_t, 512> reg = {};
	std::array<Channel, 18> channel;  // OPL3 chips have 18 channels

	std::array<int, 18 * 4> pan; // channels output masks 4 per channel
	                             //    0xffffffff = enable
	unsigned eg_cnt{0};          // global envelope generator counter
	unsigned noise_rng{1};       // 23 bit noise shift register

	// LFO
	using LFOAMIndex = FixedPoint< 6>;
	using LFOPMIndex = FixedPoint<10>;
	LFOAMIndex lfo_am_cnt{0};
	LFOPMIndex lfo_pm_cnt{0};
	bool lfo_am_depth{false};
	uint8_t lfo_pm_depth_range{0};

	uint8_t rhythm{0};		// Rhythm mode
	bool nts{false};			// NTS (note select)
	bool OPL3_mode{false};		// OPL3 extension enable flag

	uint8_t status{0};		// status flag
	uint8_t status2{0};
	uint8_t statusMask{0};		// status mask

	bool alreadySignaledNEW2{false};
	const bool isYMF278;		// true iff this is actually a YMF278
					// ATM only used for NEW2 bit
};
SERIALIZE_CLASS_VERSION(YMF262, 2);

} // namespace openmsx

#endif