const (
	ProtocolVersion30 = (3 << 16) | 0 //lint:ignore SA4016 x
	ProtocolVersion32 = (3 << 16) | 2 // PostgreSQL ≥18.
	CancelRequestCode = (1234 << 16) | 5678
	NegotiateSSLCode  = (1234 << 16) | 5679
	NegotiateGSSCode  = (1234 << 16) | 5680
)

const (
	Bind                = RequestCode('B')
	Close               = RequestCode('C')
	Describe            = RequestCode('D')
	Execute             = RequestCode('E')
	FunctionCall        = RequestCode('F')
	Flush               = RequestCode('H')
	Parse               = RequestCode('P')
	Query               = RequestCode('Q')
	Sync                = RequestCode('S')
	Terminate           = RequestCode('X')
	CopyFail            = RequestCode('f')
	GSSResponse         = RequestCode('p')
	PasswordMessage     = RequestCode('p')
	SASLInitialResponse = RequestCode('p')
	SASLResponse        = RequestCode('p')
	CopyDoneRequest     = RequestCode('c')
	CopyDataRequest     = RequestCode('d')
)

const (
	ParseComplete            = ResponseCode('1')
	BindComplete             = ResponseCode('2')
	CloseComplete            = ResponseCode('3')
	NotificationResponse     = ResponseCode('A')
	CommandComplete          = ResponseCode('C')
	DataRow                  = ResponseCode('D')
	ErrorResponse            = ResponseCode('E')
	CopyInResponse           = ResponseCode('G')
	CopyOutResponse          = ResponseCode('H')
	EmptyQueryResponse       = ResponseCode('I')
	BackendKeyData           = ResponseCode('K')
	NoticeResponse           = ResponseCode('N')
	AuthenticationRequest    = ResponseCode('R')
	ParameterStatus          = ResponseCode('S')
	RowDescription           = ResponseCode('T')
	FunctionCallResponse     = ResponseCode('V')
	CopyBothResponse         = ResponseCode('W')
	ReadyForQuery            = ResponseCode('Z')
	NoData                   = ResponseCode('n')
	PortalSuspended          = ResponseCode('s')
	ParameterDescription     = ResponseCode('t')
	NegotiateProtocolVersion = ResponseCode('v')
	CopyDoneResponse         = ResponseCode('c')
	CopyDataResponse         = ResponseCode('d')
)

const (
	AuthReqOk       = AuthCode(0) // User is authenticated
	AuthReqKrb4     = AuthCode(1) // Kerberos V4. Not supported any more.
	AuthReqKrb5     = AuthCode(2) // Kerberos V5. Not supported any more.
	AuthReqPassword = AuthCode(3) // Password
	AuthReqCrypt    = AuthCode(4) // crypt password. Not supported any more.
	AuthReqMD5      = AuthCode(5) // md5 password

	AuthReqGSS      = AuthCode(7)  // GSSAPI without wrap()
	AuthReqGSSCont  = AuthCode(8)  // Continue GSS exchanges
	AuthReqSSPI     = AuthCode(9)  // SSPI negotiate without wrap()
	AuthReqSASL     = AuthCode(10) // Begin SASL authentication
	AuthReqSASLCont = AuthCode(11) // Continue SASL authentication
	AuthReqSASLFin  = AuthCode(12) // Final SASL message
)

const (
	MaxErrlen = 30_000 // https://github.com/postgres/postgres/blob/c6a10a89f/src/interfaces/libpq/fe-connect.c#L4067
)

const MaxUint32 = math.MaxUint32

type AuthCode int32

type RequestCode byte

type ResponseCode byte