package yamux

const (
	// protoVersion is the only version we support
	protoVersion = 0
)

const (
	// Data is used for data frames. They are followed
	// by length bytes worth of payload.
	typeData uint8 = iota

	// WindowUpdate is used to change the window of
	// a given stream. The length indicates the delta
	// update to the window.
	typeWindowUpdate

	// Ping is sent as a keep-alive or to measure
	// the RTT. The StreamID and Length value are echoed
	// back in the response.
	typePing

	// GoAway is sent to terminate a session. The StreamID
	// should be 0 and the length is an error code.
	typeGoAway
)

const (
	// SYN is sent to signal a new stream. May
	// be sent with a data payload
	flagSYN uint8 = 1 << iota

	// ACK is sent to acknowledge a new stream. May
	// be sent with a data payload
	flagACK

	// FIN is sent to half-close the given stream.
	// May be sent with a data payload.
	flagFIN

	// RST is used to hard close a given stream.
	flagRST

	// LZW is used to indicate that the payload is
	// compressed with the LZW algorithm
	flagLZW
)

const (
	// initialSessionWindow is the initial session window size
	initialSessionWindow = 2 * 1024 * 1024

	// initialStreamWindow is the initial stream window size
	initialStreamWindow = 256 * 1024
)

const (
	// goAwayNormal is sent on a normal termination
	goAwayNormal uint32 = iota

	// goAwayProtoErr sent on a protocol error
	goAwayProtoErr

	// goAwayInternalErr sent on an internal error
	goAwayInternalErr
)