contractcourt

type ArbChannel interface {
	// ForceCloseChan should force close the contract that this attendant
	// is watching over. We'll use this when we decide that we need to go
	// to chain. It should in addition tell the switch to remove the
	// corresponding link, such that we won't accept any new updates. The
	// returned summary contains all items needed to eventually resolve all
	// outputs on chain.
	ForceCloseChan() (*lnwallet.LocalForceCloseSummary, error)

	// NewAnchorResolutions returns the anchor resolutions for currently
	// valid commitment transactions.
	NewAnchorResolutions() (*lnwallet.AnchorResolutions, error)
}

type ArbitratorLog interface {

	// CurrentState returns the current state of the ChannelArbitrator. It
	// takes an optional database transaction, which will be used if it is
	// non-nil, otherwise the lookup will be done in its own transaction.
	CurrentState(tx kvdb.RTx) (ArbitratorState, error)

	// CommitState persists, the current state of the chain attendant.
	CommitState(ArbitratorState) error

	// InsertUnresolvedContracts inserts a set of unresolved contracts into
	// the log. The log will then persistently store each contract until
	// they've been swapped out, or resolved. It takes a set of report which
	// should be written to disk if as well if it is non-nil.
	InsertUnresolvedContracts(reports []*channeldb.ResolverReport,
		resolvers ...ContractResolver) error

	// FetchUnresolvedContracts returns all unresolved contracts that have
	// been previously written to the log.
	FetchUnresolvedContracts() ([]ContractResolver, error)

	// SwapContract performs an atomic swap of the old contract for the new
	// contract. This method is used when after a contract has been fully
	// resolved, it produces another contract that needs to be resolved.
	SwapContract(old ContractResolver, new ContractResolver) error

	// ResolveContract marks a contract as fully resolved. Once a contract
	// has been fully resolved, it is deleted from persistent storage.
	ResolveContract(ContractResolver) error

	// LogContractResolutions stores a complete contract resolution for the
	// contract under watch. This method will be called once the
	// ChannelArbitrator either force closes a channel, or detects that the
	// remote party has broadcast their commitment on chain.
	LogContractResolutions(*ContractResolutions) error

	// FetchContractResolutions fetches the set of previously stored
	// contract resolutions from persistent storage.
	FetchContractResolutions() (*ContractResolutions, error)

	// InsertConfirmedCommitSet stores the known set of active HTLCs at the
	// time channel closure. We'll use this to reconstruct our set of chain
	// actions anew based on the confirmed and pending commitment state.
	InsertConfirmedCommitSet(c *CommitSet) error

	// FetchConfirmedCommitSet fetches the known confirmed active HTLC set
	// from the database. It takes an optional database transaction, which
	// will be used if it is non-nil, otherwise the lookup will be done in
	// its own transaction.
	FetchConfirmedCommitSet(tx kvdb.RTx) (*CommitSet, error)

	// FetchChainActions attempts to fetch the set of previously stored
	// chain actions. We'll use this upon restart to properly advance our
	// state machine forward.
	//
	// NOTE: This method only exists in order to be able to serve nodes had
	// channels in the process of closing before the CommitSet struct was
	// introduced.
	FetchChainActions() (ChainActionMap, error)

	// WipeHistory is to be called ONLY once *all* contracts have been
	// fully resolved, and the channel closure if finalized. This method
	// will delete all on-disk state within the persistent log.
	WipeHistory() error
}

type ArbitratorState uint8

type BreachArbiter struct {
	sync.Mutex
	// contains filtered or unexported fields
}

type BreachCloseInfo struct {
	*BreachResolution
	*lnwallet.AnchorResolution

	// CommitHash is the hash of the commitment transaction.
	CommitHash chainhash.Hash

	// CommitSet is the set of known valid commitments at the time the
	// breach occurred on-chain.
	CommitSet CommitSet

	// CloseSummary gives the recipient of the BreachCloseInfo information
	// to mark the channel closed in the database.
	CloseSummary channeldb.ChannelCloseSummary
}

type BreachConfig struct {
	// CloseLink allows the breach arbiter to shutdown any channel links for
	// which it detects a breach, ensuring now further activity will
	// continue across the link. The method accepts link's channel point and
	// a close type to be included in the channel close summary.
	CloseLink func(*wire.OutPoint, ChannelCloseType)

	// DB provides access to the user's channels, allowing the breach
	// arbiter to determine the current state of a user's channels, and how
	// it should respond to channel closure.
	DB *channeldb.ChannelStateDB

	// Estimator is used by the breach arbiter to determine an appropriate
	// fee level when generating, signing, and broadcasting sweep
	// transactions.
	Estimator chainfee.Estimator

	// GenSweepScript generates the receiving scripts for swept outputs.
	GenSweepScript func() ([]byte, error)

	// Notifier provides a publish/subscribe interface for event driven
	// notifications regarding the confirmation of txids.
	Notifier chainntnfs.ChainNotifier

	// PublishTransaction facilitates the process of broadcasting a
	// transaction to the network.
	PublishTransaction func(*wire.MsgTx, string) error

	// ContractBreaches is a channel where the BreachArbiter will receive
	// notifications in the event of a contract breach being observed. A
	// ContractBreachEvent must be ACKed by the BreachArbiter, such that
	// the sending subsystem knows that the event is properly handed off.
	ContractBreaches <-chan *ContractBreachEvent

	// Signer is used by the breach arbiter to generate sweep transactions,
	// which move coins from previously open channels back to the user's
	// wallet.
	Signer input.Signer

	// Store is a persistent resource that maintains information regarding
	// breached channels. This is used in conjunction with DB to recover
	// from crashes, restarts, or other failures.
	Store RetributionStorer
}

type BreachResolution struct {
	FundingOutPoint wire.OutPoint
}

type ChainAction uint8

type ChainActionMap map[ChainAction][]channeldb.HTLC

type ChainArbitrator struct {
	sync.Mutex
	// contains filtered or unexported fields
}

type ChainArbitratorConfig struct {
	// ChainHash is the chain that this arbitrator is to operate within.
	ChainHash chainhash.Hash

	// IncomingBroadcastDelta is the delta that we'll use to decide when to
	// broadcast our commitment transaction if we have incoming htlcs. This
	// value should be set based on our current fee estimation of the
	// commitment transaction. We use this to determine when we should
	// broadcast instead of just the HTLC timeout, as we want to ensure
	// that the commitment transaction is already confirmed, by the time the
	// HTLC expires. Otherwise we may end up not settling the htlc on-chain
	// because the other party managed to time it out.
	IncomingBroadcastDelta uint32

	// OutgoingBroadcastDelta is the delta that we'll use to decide when to
	// broadcast our commitment transaction if there are active outgoing
	// htlcs. This value can be lower than the incoming broadcast delta.
	OutgoingBroadcastDelta uint32

	// NewSweepAddr is a function that returns a new address under control
	// by the wallet. We'll use this to sweep any no-delay outputs as a
	// result of unilateral channel closes.
	//
	// NOTE: This SHOULD return a p2wkh script.
	NewSweepAddr func() ([]byte, error)

	// PublishTx reliably broadcasts a transaction to the network. Once
	// this function exits without an error, then they transaction MUST
	// continually be rebroadcast if needed.
	PublishTx func(*wire.MsgTx, string) error

	// DeliverResolutionMsg is a function that will append an outgoing
	// message to the "out box" for a ChannelLink. This is used to cancel
	// backwards any HTLC's that are either dust, we're timing out, or
	// settling on-chain to the incoming link.
	DeliverResolutionMsg func(...ResolutionMsg) error

	// MarkLinkInactive is a function closure that the ChainArbitrator will
	// use to mark that active HTLC's shouldn't be attempted to be routed
	// over a particular channel. This function will be called in that a
	// ChannelArbitrator decides that it needs to go to chain in order to
	// resolve contracts.
	//
	// TODO(roasbeef): rename, routing based
	MarkLinkInactive func(wire.OutPoint) error

	// ContractBreach is a function closure that the ChainArbitrator will
	// use to notify the breachArbiter about a contract breach. It should
	// only return a non-nil error when the breachArbiter has preserved
	// the necessary breach info for this channel point. Once the breach
	// resolution is persisted in the channel arbitrator, it will be safe
	// to mark the channel closed.
	ContractBreach func(wire.OutPoint, *lnwallet.BreachRetribution) error

	// IsOurAddress is a function that returns true if the passed address
	// is known to the underlying wallet. Otherwise, false should be
	// returned.
	IsOurAddress func(btcutil.Address) bool

	// IncubateOutput sends either an incoming HTLC, an outgoing HTLC, or
	// both to the utxo nursery. Once this function returns, the nursery
	// should have safely persisted the outputs to disk, and should start
	// the process of incubation. This is used when a resolver wishes to
	// pass off the output to the nursery as we're only waiting on an
	// absolute/relative item block.
	IncubateOutputs func(wire.OutPoint, *lnwallet.OutgoingHtlcResolution,
		*lnwallet.IncomingHtlcResolution, uint32) error

	// PreimageDB is a global store of all known pre-images. We'll use this
	// to decide if we should broadcast a commitment transaction to claim
	// an HTLC on-chain.
	PreimageDB WitnessBeacon

	// Notifier is an instance of a chain notifier we'll use to watch for
	// certain on-chain events.
	Notifier chainntnfs.ChainNotifier

	// Mempool is the a mempool watcher that allows us to watch for events
	// happened in mempool.
	Mempool chainntnfs.MempoolWatcher

	// Signer is a signer backed by the active lnd node. This should be
	// capable of producing a signature as specified by a valid
	// SignDescriptor.
	Signer input.Signer

	// FeeEstimator will be used to return fee estimates.
	FeeEstimator chainfee.Estimator

	// ChainIO allows us to query the state of the current main chain.
	ChainIO lnwallet.BlockChainIO

	// DisableChannel disables a channel, resulting in it not being able to
	// forward payments.
	DisableChannel func(wire.OutPoint) error

	// Sweeper allows resolvers to sweep their final outputs.
	Sweeper UtxoSweeper

	// Registry is the invoice database that is used by resolvers to lookup
	// preimages and settle invoices.
	Registry Registry

	// NotifyClosedChannel is a function closure that the ChainArbitrator
	// will use to notify the ChannelNotifier about a newly closed channel.
	NotifyClosedChannel func(wire.OutPoint)

	// NotifyFullyResolvedChannel is a function closure that the
	// ChainArbitrator will use to notify the ChannelNotifier about a newly
	// resolved channel. The main difference to NotifyClosedChannel is that
	// in case of a local force close the NotifyClosedChannel is called when
	// the published commitment transaction confirms while
	// NotifyFullyResolvedChannel is only called when the channel is fully
	// resolved (which includes sweeping any time locked funds).
	NotifyFullyResolvedChannel func(point wire.OutPoint)

	// OnionProcessor is used to decode onion payloads for on-chain
	// resolution.
	OnionProcessor OnionProcessor

	// PaymentsExpirationGracePeriod indicates a time window we let the
	// other node to cancel an outgoing htlc that our node has initiated and
	// has timed out.
	PaymentsExpirationGracePeriod time.Duration

	// IsForwardedHTLC checks for a given htlc, identified by channel id and
	// htlcIndex, if it is a forwarded one.
	IsForwardedHTLC func(chanID lnwire.ShortChannelID, htlcIndex uint64) bool

	// Clock is the clock implementation that ChannelArbitrator uses.
	// It is useful for testing.
	Clock clock.Clock

	// SubscribeBreachComplete is used by the breachResolver to register a
	// subscription that notifies when the breach resolution process is
	// complete.
	SubscribeBreachComplete func(op *wire.OutPoint, c chan struct{}) (
		bool, error)

	// PutFinalHtlcOutcome stores the final outcome of an htlc in the
	// database.
	PutFinalHtlcOutcome func(chanId lnwire.ShortChannelID,
		htlcId uint64, settled bool) error

	// HtlcNotifier is an interface that htlc events are sent to.
	HtlcNotifier HtlcNotifier
}

type ChainEventSubscription struct {
	// ChanPoint is that channel that chain events will be dispatched for.
	ChanPoint wire.OutPoint

	// RemoteUnilateralClosure is a channel that will be sent upon in the
	// event that the remote party's commitment transaction is confirmed.
	RemoteUnilateralClosure chan *RemoteUnilateralCloseInfo

	// LocalUnilateralClosure is a channel that will be sent upon in the
	// event that our commitment transaction is confirmed.
	LocalUnilateralClosure chan *LocalUnilateralCloseInfo

	// CooperativeClosure is a signal that will be sent upon once a
	// cooperative channel closure has been detected confirmed.
	CooperativeClosure chan *CooperativeCloseInfo

	// ContractBreach is a channel that will be sent upon if we detect a
	// contract breach. The struct sent across the channel contains all the
	// material required to bring the cheating channel peer to justice.
	ContractBreach chan *BreachCloseInfo

	// Cancel cancels the subscription to the event stream for a particular
	// channel. This method should be called once the caller no longer needs to
	// be notified of any on-chain events for a particular channel.
	Cancel func()
}

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

type ChannelArbitratorConfig struct {
	// ChanPoint is the channel point that uniquely identifies this
	// channel.
	ChanPoint wire.OutPoint

	// Channel is the full channel data structure. For legacy channels, this
	// field may not always be set after a restart.
	Channel ArbChannel

	// ShortChanID describes the exact location of the channel within the
	// chain. We'll use this to address any messages that we need to send
	// to the switch during contract resolution.
	ShortChanID lnwire.ShortChannelID

	// 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 *ChainEventSubscription

	// MarkCommitmentBroadcasted should mark the channel as the commitment
	// being broadcast, and we are waiting for the commitment to confirm.
	MarkCommitmentBroadcasted func(*wire.MsgTx, bool) error

	// MarkChannelClosed marks the channel closed in the database, with the
	// passed close summary. After this method successfully returns we can
	// no longer expect to receive chain events for this channel, and must
	// be able to recover from a failure without getting the close event
	// again. It takes an optional channel status which will update the
	// channel status in the record that we keep of historical channels.
	MarkChannelClosed func(*channeldb.ChannelCloseSummary,
		...channeldb.ChannelStatus) error

	// IsPendingClose is a boolean indicating whether the channel is marked
	// as pending close in the database.
	IsPendingClose bool

	// ClosingHeight is the height at which the channel was closed. Note
	// that this value is only valid if IsPendingClose is true.
	ClosingHeight uint32

	// CloseType is the type of the close event in case IsPendingClose is
	// true. Otherwise this value is unset.
	CloseType channeldb.ClosureType

	// MarkChannelResolved is a function closure that serves to mark a
	// channel as "fully resolved". A channel itself can be considered
	// fully resolved once all active contracts have individually been
	// fully resolved.
	//
	// TODO(roasbeef): need RPC's to combine for pendingchannels RPC
	MarkChannelResolved func() error

	// PutResolverReport records a resolver report for the channel. If the
	// transaction provided is nil, the function should write the report
	// in a new transaction.
	PutResolverReport func(tx kvdb.RwTx,
		report *channeldb.ResolverReport) error

	// FetchHistoricalChannel retrieves the historical state of a channel.
	// This is mostly used to supplement the ContractResolvers with
	// additional information required for proper contract resolution.
	FetchHistoricalChannel func() (*channeldb.OpenChannel, error)

	ChainArbitratorConfig
}

type ChannelCloseType uint8

type CommitSet struct {
	// ConfCommitKey if non-nil, identifies the commitment that was
	// confirmed in the chain.
	ConfCommitKey *HtlcSetKey

	// HtlcSets stores the set of all known active HTLC for each active
	// commitment at the time of channel closure.
	HtlcSets map[HtlcSetKey][]channeldb.HTLC
}

type ContractBreachEvent struct {
	// ChanPoint is the channel point of the breached channel.
	ChanPoint wire.OutPoint

	// ProcessACK is an closure that should be called with a nil error iff
	// the breach retribution info is safely stored in the retribution
	// store. In case storing the information to the store fails, a non-nil
	// error should be used. When this closure returns, it means that the
	// contract court has marked the channel pending close in the DB, and
	// it is safe for the BreachArbiter to carry on its duty.
	ProcessACK func(error)

	// BreachRetribution is the information needed to act on this contract
	// breach.
	BreachRetribution *lnwallet.BreachRetribution
}

type ContractMaturityReport struct {
	// limboBalance is the total number of frozen coins within this
	// contract.
	LimboBalance btcutil.Amount

	// recoveredBalance is the total value that has been successfully swept
	// back to the user's wallet.
	RecoveredBalance btcutil.Amount

	// htlcs records a maturity report for each htlc output in this channel.
	Htlcs []HtlcMaturityReport
}

type ContractReport struct {
	// Outpoint is the final output that will be swept back to the wallet.
	Outpoint wire.OutPoint

	// Type indicates the type of the reported output.
	Type ReportOutputType

	// Amount is the final value that will be swept in back to the wallet.
	Amount btcutil.Amount

	// MaturityHeight is the absolute block height that this output will
	// mature at.
	MaturityHeight uint32

	// Stage indicates whether the htlc is in the CLTV-timeout stage (1) or
	// the CSV-delay stage (2). A stage 1 htlc's maturity height will be set
	// to its expiry height, while a stage 2 htlc's maturity height will be
	// set to its confirmation height plus the maturity requirement.
	Stage uint32

	// LimboBalance is the total number of frozen coins within this
	// contract.
	LimboBalance btcutil.Amount

	// RecoveredBalance is the total value that has been successfully swept
	// back to the user's wallet.
	RecoveredBalance btcutil.Amount
}

type ContractResolutions struct {
	// CommitHash is the txid of the commitment transaction.
	CommitHash chainhash.Hash

	// CommitResolution contains all data required to fully resolve a
	// commitment output.
	CommitResolution *lnwallet.CommitOutputResolution

	// HtlcResolutions contains all data required to fully resolve any
	// incoming+outgoing HTLC's present within the commitment transaction.
	HtlcResolutions lnwallet.HtlcResolutions

	// AnchorResolution contains the data required to sweep the anchor
	// output. If the channel type doesn't include anchors, the value of
	// this field will be nil.
	AnchorResolution *lnwallet.AnchorResolution

	// BreachResolution contains the data required to manage the lifecycle
	// of a breach in the ChannelArbitrator.
	BreachResolution *BreachResolution
}

type ContractResolver interface {
	// ResolverKey returns an identifier which should be globally unique
	// for this particular resolver within the chain the original contract
	// resides within.
	ResolverKey() []byte

	// Resolve instructs the contract resolver to resolve the output
	// on-chain. Once the output has been *fully* resolved, the function
	// should return immediately with a nil ContractResolver value for the
	// first return value.  In the case that the contract requires further
	// resolution, then another resolve is returned.
	//
	// NOTE: This function MUST be run as a goroutine.
	Resolve() (ContractResolver, error)

	// SupplementState allows the user of a ContractResolver to supplement
	// it with state required for the proper resolution of a contract.
	SupplementState(*channeldb.OpenChannel)

	// IsResolved returns true if the stored state in the resolve is fully
	// resolved. In this case the target output can be forgotten.
	IsResolved() bool

	// Encode writes an encoded version of the ContractResolver into the
	// passed Writer.
	Encode(w io.Writer) error

	// Stop signals the resolver to cancel any current resolution
	// processes, and suspend.
	Stop()
}

type ContractSignals struct {
	// ShortChanID is the up to date short channel ID for a contract. This
	// can change either if when the contract was added it didn't yet have
	// a stable identifier, or in the case of a reorg.
	ShortChanID lnwire.ShortChannelID
}

type ContractUpdate struct {
	// HtlcKey identifies which commitment the HTLCs below are present on.
	HtlcKey HtlcSetKey

	// Htlcs are the of active HTLCs on the commitment identified by the
	// above HtlcKey.
	Htlcs []channeldb.HTLC
}

type CooperativeCloseInfo struct {
	*channeldb.ChannelCloseSummary
}

type HtlcMaturityReport struct {
	// Outpoint is the final output that will be swept back to the wallet.
	Outpoint wire.OutPoint

	// Amount is the final value that will be swept in back to the wallet.
	Amount btcutil.Amount

	// MaturityHeight is the absolute block height that this output will
	// mature at.
	MaturityHeight uint32

	// Stage indicates whether the htlc is in the CLTV-timeout stage (1) or
	// the CSV-delay stage (2). A stage 1 htlc's maturity height will be set
	// to its expiry height, while a stage 2 htlc's maturity height will be
	// set to its confirmation height plus the maturity requirement.
	Stage uint32
}

type HtlcNotifier interface {
	// NotifyFinalHtlcEvent notifies the HtlcNotifier that the final outcome
	// for an htlc has been determined.
	NotifyFinalHtlcEvent(key models.CircuitKey,
		info channeldb.FinalHtlcInfo)
}

type HtlcSetKey struct {
	// IsRemote denotes if the HTLCs are on the remote commitment
	// transaction.
	IsRemote bool

	// IsPending denotes if the commitment transaction that HTLCS are on
	// are pending (the higher of two unrevoked commitments).
	IsPending bool
}

type LocalUnilateralCloseInfo struct {
	*chainntnfs.SpendDetail
	*lnwallet.LocalForceCloseSummary
	*channeldb.ChannelCloseSummary

	// CommitSet is the set of known valid commitments at the time the
	// remote party's commitment hit the chain.
	CommitSet CommitSet
}

type NurseryConfig struct {
	// ChainIO is used by the utxo nursery to determine the current block
	// height, which drives the incubation of the nursery's outputs.
	ChainIO lnwallet.BlockChainIO

	// ConfDepth is the number of blocks the nursery store waits before
	// determining outputs in the chain as confirmed.
	ConfDepth uint32

	// FetchClosedChannels provides access to a user's channels, such that
	// they can be marked fully closed after incubation has concluded.
	FetchClosedChannels func(pendingOnly bool) (
		[]*channeldb.ChannelCloseSummary, error)

	// FetchClosedChannel provides access to the close summary to extract a
	// height hint from.
	FetchClosedChannel func(chanID *wire.OutPoint) (
		*channeldb.ChannelCloseSummary, error)

	// Notifier provides the utxo nursery the ability to subscribe to
	// transaction confirmation events, which advance outputs through their
	// persistence state transitions.
	Notifier chainntnfs.ChainNotifier

	// PublishTransaction facilitates the process of broadcasting a signed
	// transaction to the appropriate network.
	PublishTransaction func(*wire.MsgTx, string) error

	// Store provides access to and modification of the persistent state
	// maintained about the utxo nursery's incubating outputs.
	Store NurseryStorer

	// Sweep sweeps an input back to the wallet.
	SweepInput func(input.Input, sweep.Params) (chan sweep.Result, error)
}

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

type NurseryStorer interface {
	// Incubate registers a set of CSV delayed outputs (incoming HTLC's on
	// our commitment transaction, or a commitment output), and a slice of
	// outgoing htlc outputs to be swept back into the user's wallet. The
	// event is persisted to disk, such that the nursery can resume the
	// incubation process after a potential crash.
	Incubate([]kidOutput, []babyOutput) error

	// CribToKinder atomically moves a babyOutput in the crib bucket to the
	// kindergarten bucket. Baby outputs are outgoing HTLC's which require
	// us to go to the second-layer to claim. The now mature kidOutput
	// contained in the babyOutput will be stored as it waits out the
	// kidOutput's CSV delay.
	CribToKinder(*babyOutput) error

	// PreschoolToKinder atomically moves a kidOutput from the preschool
	// bucket to the kindergarten bucket. This transition should be executed
	// after receiving confirmation of the preschool output. Incoming HTLC's
	// we need to go to the second-layer to claim, and also our commitment
	// outputs fall into this class.
	//
	// An additional parameter specifies the last graduated height. This is
	// used in case of late registration. It schedules the output for sweep
	// at the next epoch even though it has already expired earlier.
	PreschoolToKinder(kid *kidOutput, lastGradHeight uint32) error

	// GraduateKinder atomically moves an output at the provided height into
	// the graduated status. This involves removing the kindergarten entries
	// from both the height and channel indexes. The height bucket will be
	// opportunistically pruned from the height index as outputs are
	// removed.
	GraduateKinder(height uint32, output *kidOutput) error

	// FetchPreschools returns a list of all outputs currently stored in
	// the preschool bucket.
	FetchPreschools() ([]kidOutput, error)

	// FetchClass returns a list of kindergarten and crib outputs whose
	// timelocks expire at the given height.
	FetchClass(height uint32) ([]kidOutput, []babyOutput, error)

	// HeightsBelowOrEqual returns the lowest non-empty heights in the
	// height index, that exist at or below the provided upper bound.
	HeightsBelowOrEqual(height uint32) ([]uint32, error)

	// ForChanOutputs iterates over all outputs being incubated for a
	// particular channel point. This method accepts a callback that allows
	// the caller to process each key-value pair. The key will be a prefixed
	// outpoint, and the value will be the serialized bytes for an output,
	// whose type should be inferred from the key's prefix.
	ForChanOutputs(*wire.OutPoint, func([]byte, []byte) error, func()) error

	// ListChannels returns all channels the nursery is currently tracking.
	ListChannels() ([]wire.OutPoint, error)

	// IsMatureChannel determines the whether or not all of the outputs in a
	// particular channel bucket have been marked as graduated.
	IsMatureChannel(*wire.OutPoint) (bool, error)

	// RemoveChannel channel erases all entries from the channel bucket for
	// the provided channel point, this method should only be called if
	// IsMatureChannel indicates the channel is ready for removal.
	RemoveChannel(*wire.OutPoint) error
}

type OnionProcessor interface {
	// ReconstructHopIterator attempts to decode a valid sphinx packet from
	// the passed io.Reader instance.
	ReconstructHopIterator(r io.Reader, rHash []byte) (hop.Iterator, error)
}

type Registry 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.
	NotifyExitHopHtlc(payHash lntypes.Hash, paidAmount lnwire.MilliSatoshi,
		expiry uint32, currentHeight int32,
		circuitKey models.CircuitKey, hodlChan chan<- interface{},
		payload invoices.Payload) (invoices.HtlcResolution, error)

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

type RemoteUnilateralCloseInfo struct {
	*lnwallet.UnilateralCloseSummary

	// CommitSet is the set of known valid commitments at the time the
	// remote party's commitment hit the chain.
	CommitSet CommitSet
}

type ReportOutputType uint8

type ResolutionMsg struct {
	// SourceChan identifies the channel that this message is being sent
	// from. This is the channel's short channel ID.
	SourceChan lnwire.ShortChannelID

	// HtlcIndex is the index of the contract within the original
	// commitment trace.
	HtlcIndex uint64

	// Failure will be non-nil if the incoming contract should be canceled
	// all together. This can happen if the outgoing contract was dust, if
	// if the outgoing HTLC timed out.
	Failure lnwire.FailureMessage

	// PreImage will be non-nil if the incoming contract can successfully
	// be redeemed. This can happen if we learn of the preimage from the
	// outgoing HTLC on-chain.
	PreImage *[32]byte
}

type ResolverConfig struct {
	// ChannelArbitratorConfig contains all the interfaces and closures
	// required for the resolver to interact with outside sub-systems.
	ChannelArbitratorConfig

	// Checkpoint allows a resolver to check point its state. This function
	// should write the state of the resolver to persistent storage, and
	// return a non-nil error upon success. It takes a resolver report,
	// which contains information about the outcome and should be written
	// to disk if non-nil.
	Checkpoint func(ContractResolver, ...*channeldb.ResolverReport) error
}

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

type RetributionStorer interface {
	// Add persists the retributionInfo to disk, using the information's
	// chanPoint as the key. This method should overwrite any existing
	// entries found under the same key, and an error should be raised if
	// the addition fails.
	Add(retInfo *retributionInfo) error

	// IsBreached queries the retribution store to see if the breach arbiter
	// is aware of any breaches for the provided channel point.
	IsBreached(chanPoint *wire.OutPoint) (bool, error)

	// Remove deletes the retributionInfo from disk, if any exists, under
	// the given key. An error should be re raised if the removal fails.
	Remove(key *wire.OutPoint) error

	// ForAll iterates over the existing on-disk contents and applies a
	// chosen, read-only callback to each. This method should ensure that it
	// immediately propagate any errors generated by the callback.
	ForAll(cb func(*retributionInfo) error, reset func()) error
}

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

type UtxoSweeper interface {
	// SweepInput sweeps inputs back into the wallet.
	SweepInput(input input.Input, params sweep.Params) (chan sweep.Result,
		error)

	// CreateSweepTx accepts a list of inputs and signs and generates a txn
	// that spends from them. This method also makes an accurate fee
	// estimate before generating the required witnesses.
	CreateSweepTx(inputs []input.Input, feePref sweep.FeePreference,
		currentBlockHeight uint32) (*wire.MsgTx, error)

	// RelayFeePerKW returns the minimum fee rate required for transactions
	// to be relayed.
	RelayFeePerKW() chainfee.SatPerKWeight

	// UpdateParams allows updating the sweep parameters of a pending input
	// in the UtxoSweeper. This function can be used to provide an updated
	// fee preference that will be used for a new sweep transaction of the
	// input that will act as a replacement transaction (RBF) of the
	// original sweeping transaction, if any.
	UpdateParams(input wire.OutPoint, params sweep.ParamsUpdate) (
		chan sweep.Result, error)
}

type WitnessBeacon interface {
	// SubscribeUpdates returns a channel that will be sent upon *each* time
	// a new preimage is discovered.
	SubscribeUpdates(chanID lnwire.ShortChannelID, htlc *channeldb.HTLC,
		payload *hop.Payload,
		nextHopOnionBlob []byte) (*WitnessSubscription, error)

	// LookupPreImage attempts to lookup a preimage in the global cache.
	// True is returned for the second argument if the preimage is found.
	LookupPreimage(payhash lntypes.Hash) (lntypes.Preimage, bool)

	// AddPreimages adds a batch of newly discovered preimages to the global
	// cache, and also signals any subscribers of the newly discovered
	// witness.
	AddPreimages(preimages ...lntypes.Preimage) error
}

type WitnessSubscription struct {
	// WitnessUpdates is a channel that newly discovered witnesses will be
	// sent over.
	//
	// TODO(roasbeef): couple with WitnessType?
	WitnessUpdates <-chan lntypes.Preimage

	// CancelSubscription is a function closure that should be used by a
	// client to cancel the subscription once they are no longer interested
	// in receiving new updates.
	CancelSubscription func()
}