htlcswitch

type ChanClose struct {
	// CloseType is a variable which signals the type of channel closure the
	// peer should execute.
	CloseType contractcourt.ChannelCloseType

	// ChanPoint represent the id of the channel which should be closed.
	ChanPoint *wire.OutPoint

	// TargetFeePerKw is the ideal fee that was specified by the caller.
	// This value is only utilized if the closure type is CloseRegular.
	// This will be the starting offered fee when the fee negotiation
	// process for the cooperative closure transaction kicks off.
	TargetFeePerKw chainfee.SatPerKWeight

	// MaxFee is the highest fee the caller is willing to pay.
	//
	// NOTE: This field is only respected if the caller is the initiator of
	// the channel.
	MaxFee chainfee.SatPerKWeight

	// DeliveryScript is an optional delivery script to pay funds out to.
	DeliveryScript lnwire.DeliveryAddress

	// Updates is used by request creator to receive the notifications about
	// execution of the close channel request.
	Updates chan interface{}

	// Err is used by request creator to receive request execution error.
	Err chan error
}

type ChannelLink interface {

	// Embed the ChannelUpdateHandler interface.
	ChannelUpdateHandler

	// IsUnadvertised returns true if the underlying channel is
	// unadvertised.
	IsUnadvertised() bool

	// ChannelPoint returns the channel outpoint for the channel link.
	ChannelPoint() *wire.OutPoint

	// ShortChanID returns the short channel ID for the channel link. The
	// short channel ID encodes the exact location in the main chain that
	// the original funding output can be found.
	ShortChanID() lnwire.ShortChannelID

	// UpdateShortChanID updates the short channel ID for a link. This may
	// be required in the event that a link is created before the short
	// chan ID for it is known, or a re-org occurs, and the funding
	// transaction changes location within the chain.
	UpdateShortChanID() (lnwire.ShortChannelID, error)

	// UpdateForwardingPolicy updates the forwarding policy for the target
	// ChannelLink. Once updated, the link will use the new forwarding
	// policy to govern if it an incoming HTLC should be forwarded or not.
	UpdateForwardingPolicy(models.ForwardingPolicy)

	// CheckHtlcForward should return a nil error if the passed HTLC details
	// satisfy the current forwarding policy fo the target link. Otherwise,
	// a LinkError with a valid protocol failure message should be returned
	// in order to signal to the source of the HTLC, the policy consistency
	// issue.
	CheckHtlcForward(payHash [32]byte, incomingAmt lnwire.MilliSatoshi,
		amtToForward lnwire.MilliSatoshi,
		incomingTimeout, outgoingTimeout uint32,
		heightNow uint32, scid lnwire.ShortChannelID) *LinkError

	// CheckHtlcTransit should return a nil error if the passed HTLC details
	// satisfy the current channel policy.  Otherwise, a LinkError with a
	// valid protocol failure message should be returned in order to signal
	// the violation. This call is intended to be used for locally initiated
	// payments for which there is no corresponding incoming htlc.
	CheckHtlcTransit(payHash [32]byte, amt lnwire.MilliSatoshi,
		timeout uint32, heightNow uint32) *LinkError

	// Stats return the statistics of channel link. Number of updates,
	// total sent/received milli-satoshis.
	Stats() (uint64, lnwire.MilliSatoshi, lnwire.MilliSatoshi)

	// Peer returns the representation of remote peer with which we have
	// the channel link opened.
	Peer() lnpeer.Peer

	// AttachMailBox delivers an active MailBox to the link. The MailBox may
	// have buffered messages.
	AttachMailBox(MailBox)

	// Start/Stop are used to initiate the start/stop of the channel link
	// functioning.
	Start() error
	Stop()
	// contains filtered or unexported methods
}

type ChannelLinkConfig struct {
	// FwrdingPolicy is the initial forwarding policy to be used when
	// deciding whether to forwarding incoming HTLC's or not. This value
	// can be updated with subsequent calls to UpdateForwardingPolicy
	// targeted at a given ChannelLink concrete interface implementation.
	FwrdingPolicy models.ForwardingPolicy

	// Circuits provides restricted access to the switch's circuit map,
	// allowing the link to open and close circuits.
	Circuits CircuitModifier

	// Switch provides a reference to the HTLC switch, we only use this in
	// testing to access circuit operations not typically exposed by the
	// CircuitModifier.
	//
	// TODO(conner): remove after refactoring htlcswitch testing framework.
	Switch *Switch

	// BestHeight returns the best known height.
	BestHeight func() uint32

	// ForwardPackets attempts to forward the batch of htlcs through the
	// switch. The function returns and error in case it fails to send one or
	// more packets. The link's quit signal should be provided to allow
	// cancellation of forwarding during link shutdown.
	ForwardPackets func(chan struct{}, bool, ...*htlcPacket) error

	// DecodeHopIterators facilitates batched decoding of HTLC Sphinx onion
	// blobs, which are then used to inform how to forward an HTLC.
	//
	// NOTE: This function assumes the same set of readers and preimages
	// are always presented for the same identifier.
	DecodeHopIterators func([]byte, []hop.DecodeHopIteratorRequest) (
		[]hop.DecodeHopIteratorResponse, error)

	// ExtractErrorEncrypter function is responsible for decoding HTLC
	// Sphinx onion blob, and creating onion failure obfuscator.
	ExtractErrorEncrypter hop.ErrorEncrypterExtracter

	// FetchLastChannelUpdate retrieves the latest routing policy for a
	// target channel. This channel will typically be the outgoing channel
	// specified when we receive an incoming HTLC.  This will be used to
	// provide payment senders our latest policy when sending encrypted
	// error messages.
	FetchLastChannelUpdate func(lnwire.ShortChannelID) (*lnwire.ChannelUpdate, error)

	// Peer is a lightning network node with which we have the channel link
	// opened.
	Peer lnpeer.Peer

	// Registry is a sub-system which responsible for managing the invoices
	// in thread-safe manner.
	Registry InvoiceDatabase

	// PreimageCache is a global witness beacon that houses any new
	// preimages discovered by other links. We'll use this to add new
	// witnesses that we discover which will notify any sub-systems
	// subscribed to new events.
	PreimageCache contractcourt.WitnessBeacon

	// OnChannelFailure is a function closure that we'll call if the
	// channel failed for some reason. Depending on the severity of the
	// error, the closure potentially must force close this channel and
	// disconnect the peer.
	//
	// NOTE: The method must return in order for the ChannelLink to be able
	// to shut down properly.
	OnChannelFailure func(lnwire.ChannelID, lnwire.ShortChannelID,
		LinkFailureError)

	// UpdateContractSignals is a function closure that we'll use to update
	// outside sub-systems with this channel's latest ShortChannelID.
	UpdateContractSignals func(*contractcourt.ContractSignals) error

	// NotifyContractUpdate is a function closure that we'll use to update
	// the contractcourt and more specifically the ChannelArbitrator of the
	// latest channel state.
	NotifyContractUpdate func(*contractcourt.ContractUpdate) error

	// ChainEvents is an active subscription to the chain watcher for this
	// channel to be notified of any on-chain activity related to this
	// channel.
	ChainEvents *contractcourt.ChainEventSubscription

	// FeeEstimator is an instance of a live fee estimator which will be
	// used to dynamically regulate the current fee of the commitment
	// transaction to ensure timely confirmation.
	FeeEstimator chainfee.Estimator

	// hodl.Mask is a bitvector composed of hodl.Flags, specifying breakpoints
	// for HTLC forwarding internal to the switch.
	//
	// NOTE: This should only be used for testing.
	HodlMask hodl.Mask

	// SyncStates is used to indicate that we need send the channel
	// reestablishment message to the remote peer. It should be done if our
	// clients have been restarted, or remote peer have been reconnected.
	SyncStates bool

	// BatchTicker is the ticker that determines the interval that we'll
	// use to check the batch to see if there're any updates we should
	// flush out. By batching updates into a single commit, we attempt to
	// increase throughput by maximizing the number of updates coalesced
	// into a single commit.
	BatchTicker ticker.Ticker

	// FwdPkgGCTicker is the ticker determining the frequency at which
	// garbage collection of forwarding packages occurs. We use a
	// time-based approach, as opposed to block epochs, as to not hinder
	// syncing.
	FwdPkgGCTicker ticker.Ticker

	// PendingCommitTicker is a ticker that allows the link to determine if
	// a locally initiated commitment dance gets stuck waiting for the
	// remote party to revoke.
	PendingCommitTicker ticker.Ticker

	// BatchSize is the max size of a batch of updates done to the link
	// before we do a state update.
	BatchSize uint32

	// UnsafeReplay will cause a link to replay the adds in its latest
	// commitment txn after the link is restarted. This should only be used
	// in testing, it is here to ensure the sphinx replay detection on the
	// receiving node is persistent.
	UnsafeReplay bool

	// MinFeeUpdateTimeout represents the minimum interval in which a link
	// will propose to update its commitment fee rate. A random timeout will
	// be selected between this and MaxFeeUpdateTimeout.
	MinFeeUpdateTimeout time.Duration

	// MaxFeeUpdateTimeout represents the maximum interval in which a link
	// will propose to update its commitment fee rate. A random timeout will
	// be selected between this and MinFeeUpdateTimeout.
	MaxFeeUpdateTimeout time.Duration

	// OutgoingCltvRejectDelta defines the number of blocks before expiry of
	// an htlc where we don't offer an htlc anymore. This should be at least
	// the outgoing broadcast delta, because in any case we don't want to
	// risk offering an htlc that triggers channel closure.
	OutgoingCltvRejectDelta uint32

	// TowerClient is an optional engine that manages the signing,
	// encrypting, and uploading of justice transactions to the daemon's
	// configured set of watchtowers for legacy channels.
	TowerClient TowerClient

	// MaxOutgoingCltvExpiry is the maximum outgoing timelock that the link
	// should accept for a forwarded HTLC. The value is relative to the
	// current block height.
	MaxOutgoingCltvExpiry uint32

	// MaxFeeAllocation is the highest allocation we'll allow a channel's
	// commitment fee to be of its balance. This only applies to the
	// initiator of the channel.
	MaxFeeAllocation float64

	// MaxAnchorsCommitFeeRate is the max commitment fee rate we'll use as
	// the initiator for channels of the anchor type.
	MaxAnchorsCommitFeeRate chainfee.SatPerKWeight

	// NotifyActiveLink allows the link to tell the ChannelNotifier when a
	// link is first started.
	NotifyActiveLink func(wire.OutPoint)

	// NotifyActiveChannel allows the link to tell the ChannelNotifier when
	// channels becomes active.
	NotifyActiveChannel func(wire.OutPoint)

	// NotifyInactiveChannel allows the switch to tell the ChannelNotifier
	// when channels become inactive.
	NotifyInactiveChannel func(wire.OutPoint)

	// NotifyInactiveLinkEvent allows the switch to tell the
	// ChannelNotifier when a channel link become inactive.
	NotifyInactiveLinkEvent func(wire.OutPoint)

	// HtlcNotifier is an instance of a htlcNotifier which we will pipe htlc
	// events through.
	HtlcNotifier htlcNotifier

	// FailAliasUpdate is a function used to fail an HTLC for an
	// option_scid_alias channel.
	FailAliasUpdate func(sid lnwire.ShortChannelID,
		incoming bool) *lnwire.ChannelUpdate

	// GetAliases is used by the link and switch to fetch the set of
	// aliases for a given link.
	GetAliases func(base lnwire.ShortChannelID) []lnwire.ShortChannelID
}

type ChannelUpdateHandler interface {
	// HandleChannelUpdate handles the htlc requests as settle/add/fail
	// which sent to us from remote peer we have a channel with.
	//
	// NOTE: This function MUST be non-blocking (or block as little as
	// possible).
	HandleChannelUpdate(lnwire.Message)

	// ChanID returns the channel ID for the channel link. The channel ID
	// is a more compact representation of a channel's full outpoint.
	ChanID() lnwire.ChannelID

	// Bandwidth returns the amount of milli-satoshis which current link
	// might pass through channel link. The value returned from this method
	// represents the up to date available flow through the channel. This
	// takes into account any forwarded but un-cleared HTLC's, and any
	// HTLC's which have been set to the over flow queue.
	Bandwidth() lnwire.MilliSatoshi

	// EligibleToForward returns a bool indicating if the channel is able
	// to actively accept requests to forward HTLC's. A channel may be
	// active, but not able to forward HTLC's if it hasn't yet finalized
	// the pre-channel operation protocol with the remote peer. The switch
	// will use this function in forwarding decisions accordingly.
	EligibleToForward() bool

	// MayAddOutgoingHtlc returns an error if we may not add an outgoing
	// htlc to the channel, taking the amount of the htlc to add as a
	// parameter.
	MayAddOutgoingHtlc(lnwire.MilliSatoshi) error

	// ShutdownIfChannelClean shuts the link down if the channel state is
	// clean. This can be used with dynamic commitment negotiation or coop
	// close negotiation which require a clean channel state.
	ShutdownIfChannelClean() error
}

type CircuitFwdActions struct {
	// Adds is the subsequence of circuits that were successfully committed
	// in the circuit map.
	Adds []*PaymentCircuit

	// Drops is the subsequence of circuits for which no action should be
	// done.
	Drops []*PaymentCircuit

	// Fails is the subsequence of circuits that should be failed back by
	// the calling link.
	Fails []*PaymentCircuit
}

type CircuitKey = models.CircuitKey

type CircuitLookup interface {
	// LookupCircuit queries the circuit map for the circuit identified by
	// inKey.
	LookupCircuit(inKey CircuitKey) *PaymentCircuit

	// LookupOpenCircuit queries the circuit map for a circuit identified
	// by its outgoing circuit key.
	LookupOpenCircuit(outKey CircuitKey) *PaymentCircuit
}

type CircuitMap interface {
	CircuitModifier

	CircuitLookup

	// CommitCircuits attempts to add the given circuits to the circuit
	// map. The list of circuits is split into three distinct
	// sub-sequences, corresponding to adds, drops, and fails. Adds should
	// be forwarded to the switch, while fails should be failed back
	// locally within the calling link.
	CommitCircuits(circuit ...*PaymentCircuit) (*CircuitFwdActions, error)

	// CloseCircuit marks the circuit identified by `outKey` as closing
	// in-memory, which prevents duplicate settles/fails from completing an
	// open circuit twice.
	CloseCircuit(outKey CircuitKey) (*PaymentCircuit, error)

	// FailCircuit is used by locally failed HTLCs to mark the circuit
	// identified by `inKey` as closing in-memory, which prevents duplicate
	// settles/fails from being accepted for the same circuit.
	FailCircuit(inKey CircuitKey) (*PaymentCircuit, error)

	// LookupByPaymentHash queries the circuit map and returns all open
	// circuits that use the given payment hash.
	LookupByPaymentHash(hash [32]byte) []*PaymentCircuit

	// NumPending returns the total number of active circuits added by
	// CommitCircuits.
	NumPending() int

	// NumOpen returns the number of circuits with HTLCs that have been
	// forwarded via an outgoing link.
	NumOpen() int
}

type CircuitMapConfig struct {
	// DB provides the persistent storage engine for the circuit map.
	DB kvdb.Backend

	// FetchAllOpenChannels is a function that fetches all currently open
	// channels from the channel database.
	FetchAllOpenChannels func() ([]*channeldb.OpenChannel, error)

	// FetchClosedChannels is a function that fetches all closed channels
	// from the channel database.
	FetchClosedChannels func(
		pendingOnly bool) ([]*channeldb.ChannelCloseSummary, error)

	// ExtractErrorEncrypter derives the shared secret used to encrypt
	// errors from the obfuscator's ephemeral public key.
	ExtractErrorEncrypter hop.ErrorEncrypterExtracter

	// CheckResolutionMsg checks whether a given resolution message exists
	// for the passed CircuitKey.
	CheckResolutionMsg func(outKey *CircuitKey) error
}

type CircuitModifier interface {
	// OpenCircuits preemptively records a batch keystones that will mark
	// currently pending circuits as open. These changes can be rolled back
	// on restart if the outgoing Adds do not make it into a commitment
	// txn.
	OpenCircuits(...Keystone) error

	// TrimOpenCircuits removes a channel's open channels with htlc indexes
	// above `start`.
	TrimOpenCircuits(chanID lnwire.ShortChannelID, start uint64) error

	// DeleteCircuits removes the incoming circuit key to remove all
	// persistent references to a circuit. Returns a ErrUnknownCircuit if
	// any of the incoming keys are not known.
	DeleteCircuits(inKeys ...CircuitKey) error
}

type ClearTextError interface {
	error

	// WireMessage extracts a valid wire failure message from an internal
	// error which may contain additional metadata (which should not be
	// exposed to the network). This value may be nil in the case where
	// an unknown wire error is returned by one of our peers.
	WireMessage() lnwire.FailureMessage
}

type Config struct {
	// FwdingLog is an interface that will be used by the switch to log
	// forwarding events. A forwarding event happens each time a payment
	// circuit is successfully completed. So when we forward an HTLC, and a
	// settle is eventually received.
	FwdingLog ForwardingLog

	// LocalChannelClose kicks-off the workflow to execute a cooperative or
	// forced unilateral closure of the channel initiated by a local
	// subsystem.
	LocalChannelClose func(pubKey []byte, request *ChanClose)

	// DB is the database backend that will be used to back the switch's
	// persistent circuit map.
	DB kvdb.Backend

	// FetchAllOpenChannels is a function that fetches all currently open
	// channels from the channel database.
	FetchAllOpenChannels func() ([]*channeldb.OpenChannel, error)

	// FetchAllChannels is a function that fetches all pending open, open,
	// and waiting close channels from the database.
	FetchAllChannels func() ([]*channeldb.OpenChannel, error)

	// FetchClosedChannels is a function that fetches all closed channels
	// from the channel database.
	FetchClosedChannels func(
		pendingOnly bool) ([]*channeldb.ChannelCloseSummary, error)

	// SwitchPackager provides access to the forwarding packages of all
	// active channels. This gives the switch the ability to read arbitrary
	// forwarding packages, and ack settles and fails contained within them.
	SwitchPackager channeldb.FwdOperator

	// ExtractErrorEncrypter is an interface allowing switch to reextract
	// error encrypters stored in the circuit map on restarts, since they
	// are not stored directly within the database.
	ExtractErrorEncrypter hop.ErrorEncrypterExtracter

	// FetchLastChannelUpdate retrieves the latest routing policy for a
	// target channel. This channel will typically be the outgoing channel
	// specified when we receive an incoming HTLC.  This will be used to
	// provide payment senders our latest policy when sending encrypted
	// error messages.
	FetchLastChannelUpdate func(lnwire.ShortChannelID) (*lnwire.ChannelUpdate, error)

	// Notifier is an instance of a chain notifier that we'll use to signal
	// the switch when a new block has arrived.
	Notifier chainntnfs.ChainNotifier

	// HtlcNotifier is an instance of a htlcNotifier which we will pipe htlc
	// events through.
	HtlcNotifier htlcNotifier

	// FwdEventTicker is a signal that instructs the htlcswitch to flush any
	// pending forwarding events.
	FwdEventTicker ticker.Ticker

	// LogEventTicker is a signal instructing the htlcswitch to log
	// aggregate stats about it's forwarding during the last interval.
	LogEventTicker ticker.Ticker

	// AckEventTicker is a signal instructing the htlcswitch to ack any settle
	// fails in forwarding packages.
	AckEventTicker ticker.Ticker

	// AllowCircularRoute is true if the user has configured their node to
	// allow forwards that arrive and depart our node over the same channel.
	AllowCircularRoute bool

	// RejectHTLC is a flag that instructs the htlcswitch to reject any
	// HTLCs that are not from the source hop.
	RejectHTLC bool

	// Clock is a time source for the switch.
	Clock clock.Clock

	// MailboxDeliveryTimeout is the interval after which Adds will be
	// cancelled if they have not been yet been delivered to a link. The
	// computed deadline will expiry this long after the Adds are added to
	// a mailbox via AddPacket.
	MailboxDeliveryTimeout time.Duration

	// DustThreshold is the threshold in milli-satoshis after which we'll
	// fail incoming or outgoing dust payments for a particular channel.
	DustThreshold lnwire.MilliSatoshi

	// SignAliasUpdate is used when sending FailureMessages backwards for
	// option_scid_alias channels. This avoids a potential privacy leak by
	// replacing the public, confirmed SCID with the alias in the
	// ChannelUpdate.
	SignAliasUpdate func(u *lnwire.ChannelUpdate) (*ecdsa.Signature,
		error)

	// IsAlias returns whether or not a given SCID is an alias.
	IsAlias func(scid lnwire.ShortChannelID) bool
}

type DecayedLog struct {
	// contains filtered or unexported fields
}

type ErrorDecrypter interface {
	// DecryptError peels off each layer of onion encryption from the first
	// hop, to the source of the error. A fully populated
	// lnwire.FailureMessage is returned along with the source of the
	// error.
	DecryptError(lnwire.OpaqueReason) (*ForwardingError, error)
}

type FailureDetail interface {
	// FailureString returns the string representation of a failure
	// detail.
	FailureString() string
}

type FinalHtlcEvent struct {
	CircuitKey

	Settled bool

	// Offchain is indicating whether the htlc was resolved off-chain.
	Offchain bool

	// Timestamp is the time when this htlc was settled.
	Timestamp time.Time
}

type ForwardInterceptor func(InterceptedPacket) error

type ForwardingError struct {
	// FailureSourceIdx is the index of the node that sent the failure. With
	// this information, the dispatcher of a payment can modify their set of
	// candidate routes in response to the type of failure extracted. Index
	// zero is the self node.
	FailureSourceIdx int
	// contains filtered or unexported fields
}

type ForwardingEvent struct {
	// HtlcKey uniquely identifies the htlc, and can be used to match the
	// forwarding event with subsequent settle/fail events.
	HtlcKey

	// HtlcInfo contains details about the htlc.
	HtlcInfo

	// HtlcEventType classifies the event as part of a local send or
	// receive, or as part of a forward.
	HtlcEventType

	// Timestamp is the time when this htlc was forwarded.
	Timestamp time.Time
}

type ForwardingFailEvent struct {
	// HtlcKey uniquely identifies the htlc, and can be used to match the
	// htlc with its corresponding forwarding event.
	HtlcKey

	// HtlcEventType classifies the event as part of a local send or
	// receive, or as part of a forward.
	HtlcEventType

	// Timestamp is the time when the forwarding failure was received.
	Timestamp time.Time
}

type ForwardingLog interface {
	// AddForwardingEvents is a method that should write out the set of
	// forwarding events in a batch to persistent storage. Outside
	// sub-systems can then query the contents of the log for analysis,
	// visualizations, etc.
	AddForwardingEvents([]channeldb.ForwardingEvent) error
}

type FwdAction int

type FwdResolution struct {
	// Key is the incoming circuit key of the htlc.
	Key models.CircuitKey

	// Action is the action to take on the intercepted htlc.
	Action FwdAction

	// Preimage is the preimage that is to be used for settling if Action is
	// FwdActionSettle.
	Preimage lntypes.Preimage

	// FailureMessage is the encrypted failure message that is to be passed
	// back to the sender if action is FwdActionFail.
	FailureMessage []byte

	// FailureCode is the failure code that is to be passed back to the
	// sender if action is FwdActionFail.
	FailureCode lnwire.FailCode
}

type HtlcEventType int

type HtlcInfo struct {
	// IncomingTimelock is the time lock of the htlc on our incoming
	// channel.
	IncomingTimeLock uint32

	// OutgoingTimelock is the time lock the htlc on our outgoing channel.
	OutgoingTimeLock uint32

	// IncomingAmt is the amount of the htlc on our incoming channel.
	IncomingAmt lnwire.MilliSatoshi

	// OutgoingAmt is the amount of the htlc on our outgoing channel.
	OutgoingAmt lnwire.MilliSatoshi
}

type HtlcKey struct {
	// IncomingCircuit is the channel an htlc id of the incoming htlc.
	IncomingCircuit models.CircuitKey

	// OutgoingCircuit is the channel and htlc id of the outgoing htlc.
	OutgoingCircuit models.CircuitKey
}

type HtlcNotifier struct {
	// contains filtered or unexported fields
}

type InterceptableHtlcForwarder interface {
	// SetInterceptor sets a ForwardInterceptor.
	SetInterceptor(interceptor ForwardInterceptor)

	// Resolve resolves an intercepted packet.
	Resolve(res *FwdResolution) error
}

type InterceptableSwitch struct {
	// contains filtered or unexported fields
}

type InterceptableSwitchConfig struct {
	// Switch is a reference to the actual switch implementation that
	// packets get sent to on resume.
	Switch *Switch

	// Notifier is an instance of a chain notifier that we'll use to signal
	// the switch when a new block has arrived.
	Notifier chainntnfs.ChainNotifier

	// CltvRejectDelta defines the number of blocks before the expiry of the
	// htlc where we auto-fail an intercepted htlc to prevent channel
	// force-closure.
	CltvRejectDelta uint32

	// CltvInterceptDelta defines the number of blocks before the expiry of
	// the htlc where we don't intercept anymore. This value must be greater
	// than CltvRejectDelta, because we don't want to offer htlcs to the
	// interceptor client for which there is no time left to resolve them
	// anymore.
	CltvInterceptDelta uint32

	// RequireInterceptor indicates whether processing should block if no
	// interceptor is connected.
	RequireInterceptor bool
}

type InterceptedForward interface {
	// Packet returns the intercepted packet.
	Packet() InterceptedPacket

	// Resume notifies the intention to resume an existing hold forward. This
	// basically means the caller wants to resume with the default behavior for
	// this htlc which usually means forward it.
	Resume() error

	// Settle notifies the intention to settle an existing hold
	// forward with a given preimage.
	Settle(lntypes.Preimage) error

	// Fail notifies the intention to fail an existing hold forward with an
	// encrypted failure reason.
	Fail(reason []byte) error

	// FailWithCode notifies the intention to fail an existing hold forward
	// with the specified failure code.
	FailWithCode(code lnwire.FailCode) error
}

type InterceptedPacket struct {
	// IncomingCircuit contains the incoming channel and htlc id of the
	// packet.
	IncomingCircuit models.CircuitKey

	// OutgoingChanID is the destination channel for this packet.
	OutgoingChanID lnwire.ShortChannelID

	// Hash is the payment hash of the htlc.
	Hash lntypes.Hash

	// OutgoingExpiry is the absolute block height at which the outgoing
	// htlc expires.
	OutgoingExpiry uint32

	// OutgoingAmount is the amount to forward.
	OutgoingAmount lnwire.MilliSatoshi

	// IncomingExpiry is the absolute block height at which the incoming
	// htlc expires.
	IncomingExpiry uint32

	// IncomingAmount is the amount of the accepted htlc.
	IncomingAmount lnwire.MilliSatoshi

	// CustomRecords are user-defined records in the custom type range that
	// were included in the payload.
	CustomRecords record.CustomSet

	// OnionBlob is the onion packet for the next hop
	OnionBlob [lnwire.OnionPacketSize]byte

	// AutoFailHeight is the block height at which this intercept will be
	// failed back automatically.
	AutoFailHeight int32
}

type InvoiceDatabase interface {
	// LookupInvoice attempts to look up an invoice according to its 32
	// byte payment hash.
	LookupInvoice(lntypes.Hash) (invoices.Invoice, error)

	// NotifyExitHopHtlc attempts to mark an invoice as settled. If the
	// invoice is a debug invoice, then this method is a noop as debug
	// invoices are never fully settled. The return value describes how the
	// htlc should be resolved. If the htlc cannot be resolved immediately,
	// the resolution is sent on the passed in hodlChan later. The eob
	// field passes the entire onion hop payload into the invoice registry
	// for decoding purposes.
	NotifyExitHopHtlc(payHash lntypes.Hash, paidAmount lnwire.MilliSatoshi,
		expiry uint32, currentHeight int32,
		circuitKey models.CircuitKey, hodlChan chan<- interface{},
		payload invoices.Payload) (invoices.HtlcResolution, error)

	// CancelInvoice attempts to cancel the invoice corresponding to the
	// passed payment hash.
	CancelInvoice(payHash lntypes.Hash) error

	// SettleHodlInvoice settles a hold invoice.
	SettleHodlInvoice(preimage lntypes.Preimage) error

	// HodlUnsubscribeAll unsubscribes from all htlc resolutions.
	HodlUnsubscribeAll(subscriber chan<- interface{})
}

type Keystone struct {
	InKey  CircuitKey
	OutKey CircuitKey
}

type LinkError struct {

	// FailureDetail enriches the wire error with additional information.
	FailureDetail
	// contains filtered or unexported fields
}

type LinkFailEvent struct {
	// HtlcKey uniquely identifies the htlc.
	HtlcKey

	// HtlcInfo contains details about the htlc.
	HtlcInfo

	// HtlcEventType classifies the event as part of a local send or
	// receive, or as part of a forward.
	HtlcEventType

	// LinkError is the reason that we failed the htlc.
	LinkError *LinkError

	// Incoming is true if the htlc was failed on an incoming link.
	// If it failed on the outgoing link, it is false.
	Incoming bool

	// Timestamp is the time when the link failure occurred.
	Timestamp time.Time
}

type LinkFailureAction uint8

type LinkFailureError struct {

	// FailureAction describes what we should do to fail the channel.
	FailureAction LinkFailureAction

	// PermanentFailure indicates whether this failure is permanent, and
	// the channel should not be attempted loaded again.
	PermanentFailure bool

	// Warning denotes if this is a non-terminal error that doesn't warrant
	// failing the channel all together.
	Warning bool

	// SendData is a byte slice that will be sent to the peer. If nil a
	// generic error will be sent.
	SendData []byte
	// contains filtered or unexported fields
}

type MailBox interface {
	// AddMessage appends a new message to the end of the message queue.
	AddMessage(msg lnwire.Message) error

	// AddPacket appends a new message to the end of the packet queue.
	AddPacket(pkt *htlcPacket) error

	// HasPacket queries the packets for a circuit key, this is used to drop
	// packets bound for the switch that already have a queued response.
	HasPacket(CircuitKey) bool

	// AckPacket removes a packet from the mailboxes in-memory replay
	// buffer. This will prevent a packet from being delivered after a link
	// restarts if the switch has remained online. The returned boolean
	// indicates whether or not a packet with the passed incoming circuit
	// key was removed.
	AckPacket(CircuitKey) bool

	// FailAdd fails an UpdateAddHTLC that exists within the mailbox,
	// removing it from the in-memory replay buffer. This will prevent the
	// packet from being delivered after the link restarts if the switch has
	// remained online. The generated LinkError will show an
	// OutgoingFailureDownstreamHtlcAdd FailureDetail.
	FailAdd(pkt *htlcPacket)

	// MessageOutBox returns a channel that any new messages ready for
	// delivery will be sent on.
	MessageOutBox() chan lnwire.Message

	// PacketOutBox returns a channel that any new packets ready for
	// delivery will be sent on.
	PacketOutBox() chan *htlcPacket

	// Clears any pending wire messages from the inbox.
	ResetMessages() error

	// Reset the packet head to point at the first element in the list.
	ResetPackets() error

	// SetDustClosure takes in a closure that is used to evaluate whether
	// mailbox HTLC's are dust.
	SetDustClosure(isDust dustClosure)

	// SetFeeRate sets the feerate to be used when evaluating dust.
	SetFeeRate(feerate chainfee.SatPerKWeight)

	// DustPackets returns the dust sum for Adds in the mailbox for the
	// local and remote commitments.
	DustPackets() (lnwire.MilliSatoshi, lnwire.MilliSatoshi)

	// Start starts the mailbox and any goroutines it needs to operate
	// properly.
	Start()

	// Stop signals the mailbox and its goroutines for a graceful shutdown.
	Stop()
}

type OnionErrorDecrypter interface {
	// DecryptError attempts to decrypt the passed encrypted error response.
	// The onion failure is encrypted in backward manner, starting from the
	// node where error have occurred. As a result, in order to decrypt the
	// error we need get all shared secret and apply decryption in the
	// reverse order.
	DecryptError(encryptedData []byte) (*sphinx.DecryptedError, error)
}

type OutgoingFailure int

type PaymentCircuit struct {
	// AddRef is the forward reference of the Add update in the incoming
	// link's forwarding package. This value is set on the htlcPacket of the
	// returned settle/fail so that it can be removed from disk.
	AddRef channeldb.AddRef

	// Incoming is the circuit key identifying the incoming channel and htlc
	// index from which this ADD originates.
	Incoming CircuitKey

	// Outgoing is the circuit key identifying the outgoing channel, and the
	// HTLC index that was used to forward the ADD. It will be nil if this
	// circuit's keystone has not been set.
	Outgoing *CircuitKey

	// PaymentHash used as unique identifier of payment.
	PaymentHash [32]byte

	// IncomingAmount is the value of the HTLC from the incoming link.
	IncomingAmount lnwire.MilliSatoshi

	// OutgoingAmount specifies the value of the HTLC leaving the switch,
	// either as a payment or forwarded amount.
	OutgoingAmount lnwire.MilliSatoshi

	// ErrorEncrypter is used to re-encrypt the onion failure before
	// sending it back to the originator of the payment.
	ErrorEncrypter hop.ErrorEncrypter

	// LoadedFromDisk is set true for any circuits loaded after the circuit
	// map is reloaded from disk.
	//
	// NOTE: This value is determined implicitly during a restart. It is not
	// persisted, and should never be set outside the circuit map.
	LoadedFromDisk bool
}

type PaymentResult struct {
	// Preimage is set by the switch in case a sent HTLC was settled.
	Preimage [32]byte

	// Error is non-nil in case a HTLC send failed, and the HTLC is now
	// irrevocably canceled. If the payment failed during forwarding, this
	// error will be a *ForwardingError.
	Error error
}

type Sequencer interface {
	// NextID returns a unique sequence number for each invocation.
	NextID() (uint64, error)
}

type SettleEvent struct {
	// HtlcKey uniquely identifies the htlc, and can be used to match
	// forwards with their corresponding forwarding event.
	HtlcKey

	// Preimage that was released for settling the htlc.
	Preimage lntypes.Preimage

	// HtlcEventType classifies the event as part of a local send or
	// receive, or as part of a forward.
	HtlcEventType

	// Timestamp is the time when this htlc was settled.
	Timestamp time.Time
}

type SphinxErrorDecrypter struct {
	OnionErrorDecrypter
}

type Switch struct {
	// contains filtered or unexported fields
}

type TowerClient interface {
	// RegisterChannel persistently initializes any channel-dependent
	// parameters within the client. This should be called during link
	// startup to ensure that the client is able to support the link during
	// operation.
	RegisterChannel(lnwire.ChannelID) error

	// BackupState initiates a request to back up a particular revoked
	// state. If the method returns nil, the backup is guaranteed to be
	// successful unless the justice transaction would create dust outputs
	// when trying to abide by the negotiated policy.
	BackupState(chanID *lnwire.ChannelID, stateNum uint64) error
}

type UnknownEncrypterType hop.EncrypterType