cnct: store full htlc struct inside resolver

This change prepares for accessing the onion blob from a resolver.

contractcourt/htlc_timeout_resolver.go

@@ -41,29 +41,22 @@ type htlcTimeoutResolver struct {
 	// TODO(roasbeef): wrap above into definite resolution embedding?
 	broadcastHeight uint32
 
-	// htlcIndex is the index of this HTLC within the trace of the
-	// additional commitment state machine.
-	htlcIndex uint64
-
-	// htlcAmt is the original amount of the htlc, not taking into
-	// account any fees that may have to be paid if it goes on chain.
-	htlcAmt lnwire.MilliSatoshi
+	// htlc contains information on the htlc that we are resolving on-chain.
+	htlc channeldb.HTLC
 
 	contractResolverKit
 }
 
 // newTimeoutResolver instantiates a new timeout htlc resolver.
 func newTimeoutResolver(res lnwallet.OutgoingHtlcResolution,
-	broadcastHeight uint32, htlcIndex uint64,
-	htlcAmt lnwire.MilliSatoshi,
+	broadcastHeight uint32, htlc channeldb.HTLC,
 	resCfg ResolverConfig) *htlcTimeoutResolver {
 
 	return &htlcTimeoutResolver{
 		contractResolverKit: *newContractResolverKit(resCfg),
 		htlcResolution:      res,
 		broadcastHeight:     broadcastHeight,
-		htlcIndex:           htlcIndex,
-		htlcAmt:             htlcAmt,
+		htlc:                htlc,
 	}
 }
 
@@ -158,7 +151,7 @@ func (h *htlcTimeoutResolver) claimCleanUp(
 	// resolved, then exit.
 	if err := h.DeliverResolutionMsg(ResolutionMsg{
 		SourceChan: h.ShortChanID,
-		HtlcIndex:  h.htlcIndex,
+		HtlcIndex:  h.htlc.HtlcIndex,
 		PreImage:   &pre,
 	}); err != nil {
 		return nil, err
@@ -353,7 +346,7 @@ func (h *htlcTimeoutResolver) Resolve() (ContractResolver, error) {
 	failureMsg := &lnwire.FailPermanentChannelFailure{}
 	if err := h.DeliverResolutionMsg(ResolutionMsg{
 		SourceChan: h.ShortChanID,
-		HtlcIndex:  h.htlcIndex,
+		HtlcIndex:  h.htlc.HtlcIndex,
 		Failure:    failureMsg,
 	}); err != nil {
 		return nil, err
@@ -415,7 +408,7 @@ func (h *htlcTimeoutResolver) Encode(w io.Writer) error {
 		return err
 	}
 
-	if err := binary.Write(w, endian, h.htlcIndex); err != nil {
+	if err := binary.Write(w, endian, h.htlc.HtlcIndex); err != nil {
 		return err
 	}
 
@@ -450,7 +443,7 @@ func newTimeoutResolverFromReader(r io.Reader, resCfg ResolverConfig) (
 		return nil, err
 	}
 
-	if err := binary.Read(r, endian, &h.htlcIndex); err != nil {
+	if err := binary.Read(r, endian, &h.htlc.HtlcIndex); err != nil {
 		return nil, err
 	}
 
@@ -462,7 +455,7 @@ func newTimeoutResolverFromReader(r io.Reader, resCfg ResolverConfig) (
 //
 // NOTE: Part of the htlcContractResolver interface.
 func (h *htlcTimeoutResolver) Supplement(htlc channeldb.HTLC) {
-	h.htlcAmt = htlc.Amt
+	h.htlc = htlc
 }
 
 // HtlcPoint returns the htlc's outpoint on the commitment tx.