#ifndef WD2793_HH

#define WD2793_HH

#include "RawTrack.hh"

#include "DynamicClock.hh"

#include "EmuTime.hh"

#include "Schedulable.hh"

#include "serialize_meta.hh"

#include "CRC16.hh"

namespace openmsx {

class Scheduler;

class DiskDrive;

class MSXCliComm;

class WD2793 final : public Schedulable

{

public:

	WD2793(Scheduler& scheduler, DiskDrive& drive, MSXCliComm& cliComm,

	       EmuTime time, bool isWD1770);

	void reset(EmuTime time);

	[[nodiscard]] uint8_t getStatusReg(EmuTime time);

	[[nodiscard]] uint8_t getTrackReg (EmuTime time) const;

	[[nodiscard]] uint8_t getSectorReg(EmuTime time) const;

	[[nodiscard]] uint8_t getDataReg  (EmuTime time);

	[[nodiscard]] uint8_t peekStatusReg(EmuTime time) const;

	[[nodiscard]] uint8_t peekTrackReg (EmuTime time) const;

	[[nodiscard]] uint8_t peekSectorReg(EmuTime time) const;

	[[nodiscard]] uint8_t peekDataReg  (EmuTime time) const;

	void setCommandReg(uint8_t value, EmuTime time);

	void setTrackReg  (uint8_t value, EmuTime time);

	void setSectorReg (uint8_t value, EmuTime time);

	void setDataReg   (uint8_t value, EmuTime time);

	[[nodiscard]] bool getIRQ (EmuTime time) const;

	[[nodiscard]] bool getDTRQ(EmuTime time) const;

	[[nodiscard]] bool peekIRQ (EmuTime time) const;

	[[nodiscard]] bool peekDTRQ(EmuTime time) const;

	template<typename Archive>

	void serialize(Archive& ar, unsigned version);

	// public for serialize

	enum class FSM : uint8_t {

		NONE,

		SEEK,

		TYPE2_LOADED,

		TYPE2_NOT_FOUND,

		TYPE2_ROTATED,

		CHECK_WRITE,

		PRE_WRITE_SECTOR,

		WRITE_SECTOR,

		POST_WRITE_SECTOR,

		TYPE3_LOADED,

		TYPE3_ROTATED,

		WRITE_TRACK,

		READ_TRACK,

		IDX_IRQ

	};

private:

	void executeUntil(EmuTime time) override;

	void startType1Cmd(EmuTime time);

	void seek(EmuTime time);

	void step(EmuTime time);

	void seekNext(EmuTime time);

	void endType1Cmd(EmuTime time);

	void startType2Cmd   (EmuTime time);

	void type2Loaded     (EmuTime time);

	void type2Search     (EmuTime time);

	void type2NotFound   (EmuTime time);

	void type2Rotated    (EmuTime time);

	void startReadSector (EmuTime time);

	void startWriteSector(EmuTime time);

	void checkStartWrite (EmuTime time);

	void preWriteSector  (EmuTime time);

	void writeSectorData (EmuTime time);

	void postWriteSector (EmuTime time);

	void startType3Cmd   (EmuTime time);

	void type3Loaded     (EmuTime time);

	void type3Rotated    (EmuTime time);

	void readAddressCmd  (EmuTime time);

	void readTrackCmd    (EmuTime time);

	void startWriteTrack (EmuTime time);

	void writeTrackData  (EmuTime time);

	void startType4Cmd(EmuTime time);

	void endCmd(EmuTime time);

	void setDrqRate(unsigned trackLength);

	[[nodiscard]] bool isReady() const;

	void schedule(FSM state, EmuTime time);

private:

	DiskDrive& drive;

	MSXCliComm& cliComm;

	// DRQ is high iff current time is past this time.

	//  This clock ticks at the 'byte-rate' of the current track,

	//  typically '6250 bytes/rotation * 5 rotations/second'.

	DynamicClock drqTime{EmuTime::infinity()};

	// INTRQ is high iff current time is past this time.

	EmuTime irqTime = EmuTime::infinity();

	EmuTime pulse5 = EmuTime::infinity(); // time at which the 5th index pulse will be received

	// HLD/HLT timing

	// 1) now < hldTime   (typically: hldTime == EmuTime::infinity)

	//     ==> HLD=false, WD2793 did not request head to be loaded

	// 2) hldTime <= now < hldTime + LOAD

	//     ==> HLD=true, HLT=false, head loading is in progress

	// 3) hldTime + LOAD <= now < hldTime + LOAD + IDLE

	//     ==> HLD=true, HLT=true, head is loaded

	// 4) hldTime + LOAD + IDLE <= now

	//     ==> HLD=false, idle for 15 revolutions HLD made deactive again

	// Note: is all MSX machines I've checked so far, WD2793 pins

	//  - HLD (pin 28) is unconnected

	//  - HLT (pin 40) is connected to +5V

	// This means there is no head-load delay, or IOW as soon as the WD2793

	// requests to load the disk head, the drive responds with "ok, done".

	// So 'LOAD' is zero, and phase 2) doesn't exist. Therefor the current

	// implementation mostly ignores 'LOAD'.

	EmuTime hldTime = EmuTime::infinity(); // HLD=false

	RawTrack::Sector sectorInfo;

	int dataCurrent   = 0; // which byte in track is next to be read/write

	int dataAvailable = 0; // how many bytes left to read/write

	CRC16 crc;

	FSM fsmState;

	uint8_t statusReg;

	uint8_t commandReg = 0;

	uint8_t sectorReg;

	uint8_t trackReg;

	uint8_t dataReg;

	uint8_t dataOutReg = 0;

	bool directionIn;

	bool immediateIRQ;

	bool lastWasA1 = false;

	bool dataRegWritten = false;

	bool lastWasCRC = false;

	const bool isWD1770;

};

SERIALIZE_CLASS_VERSION(WD2793, 12);

} // namespace openmsx

#endif