congestion

type ReceiveStats struct {
	// The total number of received DATA packets, including retransmitted packets.
	Pkt  uint64
	Byte uint64

	// The total number of unique original, retransmitted or recovered by the packet filter DATA packets, received in time.
	PktUnique  uint64
	ByteUnique uint64

	// The total number of SRT DATA packets detected as presently missing (either reordered or lost).
	PktLoss  uint64
	ByteLoss uint64

	// The total number of SRT DATA packets that were actually lost, i.e. not delivered.
	PktLost uint64

	// The total number of retransmitted packets registered at the receiver side.
	PktRetrans  uint64
	ByteRetrans uint64

	// The number of packets received but ignored due to having arrived too late.
	PktBelated  uint64
	ByteBelated uint64

	// The toal number of packets that arrived out of order, but still in time.
	PktLate  uint64
	ByteLate uint64

	// The total number of dropped DATA packets and, as a result, not delivered to the upstream application. This includes packets
	// that arrived too late, already received, or already ACKed.
	PktDrop  uint64
	ByteDrop uint64

	// instantaneous
	PktBuf  uint64
	ByteBuf uint64
	MsBuf   uint64

	BytePayload uint64

	MbpsEstimatedRecvBandwidth float64
	MbpsEstimatedLinkCapacity  float64

	PktLossRate float64
}

type Receiver interface {
	// Stats returns receiver statistics.
	Stats() ReceiveStats

	// PacketRate returns the current packets and bytes per second, and the capacity of the link.
	PacketRate() (pps, bps, capacity float64)

	// Flush flushes all queued packages.
	Flush()

	// Push pushes a recieved packet to the receiver queue.
	Push(pkt packet.Packet)

	// Tick gets called from a connection in order to proceed with queued packets. The provided value for
	// now is corresponds to the timestamps in the queued packets. Those timestamps are the microseconds
	// since the start of the connection.
	Tick(now uint64)

	// SetNAKInterval sets the interval between two periodic NAK messages to the sender in microseconds.
	SetNAKInterval(nakInterval uint64)
}

type SendStats struct {
	Pkt  uint64 // Sent packets in total
	Byte uint64 // Sent bytes in total

	PktUnique  uint64
	ByteUnique uint64

	PktLoss  uint64
	ByteLoss uint64

	PktRetrans  uint64
	ByteRetrans uint64

	UsSndDuration uint64 // microseconds

	PktDrop  uint64
	ByteDrop uint64

	// instantaneous
	PktBuf  uint64
	ByteBuf uint64
	MsBuf   uint64

	PktFlightSize uint64

	UsPktSndPeriod float64 // microseconds
	BytePayload    uint64

	MbpsEstimatedInputBandwidth float64
	MbpsEstimatedSentBandwidth  float64

	PktLossRate float64
}

type Sender interface {
	// Stats returns sender statistics.
	Stats() SendStats

	// Flush flushes all queued packages.
	Flush()

	// Push pushes a packet to be send on the sender queue.
	Push(p packet.Packet)

	// Tick gets called from a connection in order to proceed with the queued packets. The provided value for
	// now is corresponds to the timestamps in the queued packets. Those timestamps are the microseconds
	// since the start of the connection.
	Tick(now uint64)

	// ACK gets called when a sequence number has been confirmed from a receiver.
	ACK(sequenceNumber circular.Number)

	// NAK get called when packets with the listed sequence number should be resend.
	NAK(sequenceNumbers []circular.Number)

	// SetDropThreshold sets the threshold in microseconds for when to drop too late packages from the queue.
	SetDropThreshold(threshold uint64)
}