From c19c872cffe19dfd26cfbf041797acfc0800111f Mon Sep 17 00:00:00 2001
From: Olaoluwa Osuntokun <laolu32@gmail.com>
Date: Fri, 29 Jun 2018 16:03:46 -0700
Subject: [PATCH] lnd: update invoiceRegistry to match new switch requirements

---
 invoiceregistry.go | 24 ++++++++++++++++++------
 rpcserver.go       |  2 +-
 witness_beacon.go  |  2 +-
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/invoiceregistry.go b/invoiceregistry.go
index 58fb0515..186089c3 100644
--- a/invoiceregistry.go
+++ b/invoiceregistry.go
@@ -9,6 +9,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/lightningnetwork/lnd/zpay32"
 	"github.com/roasbeef/btcd/chaincfg/chainhash"
 	"github.com/roasbeef/btcutil"
 )
@@ -95,10 +96,14 @@ func (i *invoiceRegistry) AddInvoice(invoice *channeldb.Invoice) error {
 	//go i.notifyClients(invoice, false)
 }
 
-// lookupInvoice looks up an invoice by its payment hash (R-Hash), if found
-// then we're able to pull the funds pending within an HTLC.
+// LookupInvoice looks up an invoice by its payment hash (R-Hash), if found
+// then we're able to pull the funds pending within an HTLC. We'll also return
+// what the expected min final CLTV delta is, pre-parsed from the payment
+// request. This may be used by callers to determine if an HTLC is well formed
+// according to the cltv delta.
+//
 // TODO(roasbeef): ignore if settled?
-func (i *invoiceRegistry) LookupInvoice(rHash chainhash.Hash) (channeldb.Invoice, error) {
+func (i *invoiceRegistry) LookupInvoice(rHash chainhash.Hash) (channeldb.Invoice, uint32, error) {
 	// First check the in-memory debug invoice index to see if this is an
 	// existing invoice added for debugging.
 	i.RLock()
@@ -107,17 +112,24 @@ func (i *invoiceRegistry) LookupInvoice(rHash chainhash.Hash) (channeldb.Invoice
 
 	// If found, then simply return the invoice directly.
 	if ok {
-		return *invoice, nil
+		return *invoice, 0, nil
 	}
 
 	// Otherwise, we'll check the database to see if there's an existing
 	// matching invoice.
 	invoice, err := i.cdb.LookupInvoice(rHash)
 	if err != nil {
-		return channeldb.Invoice{}, err
+		return channeldb.Invoice{}, 0, err
 	}
 
-	return *invoice, nil
+	payReq, err := zpay32.Decode(
+		string(invoice.PaymentRequest), activeNetParams.Params,
+	)
+	if err != nil {
+		return channeldb.Invoice{}, 0, err
+	}
+
+	return *invoice, uint32(payReq.MinFinalCLTVExpiry()), nil
 }
 
 // SettleInvoice attempts to mark an invoice as settled. If the invoice is a
diff --git a/rpcserver.go b/rpcserver.go
index 3f7e92f4..99de1e34 100644
--- a/rpcserver.go
+++ b/rpcserver.go
@@ -2799,7 +2799,7 @@ func (r *rpcServer) LookupInvoice(ctx context.Context,
 
 	rpcsLog.Tracef("[lookupinvoice] searching for invoice %x", payHash[:])
 
-	invoice, err := r.server.invoices.LookupInvoice(payHash)
+	invoice, _, err := r.server.invoices.LookupInvoice(payHash)
 	if err != nil {
 		return nil, err
 	}
diff --git a/witness_beacon.go b/witness_beacon.go
index cb0d63cd..842321b7 100644
--- a/witness_beacon.go
+++ b/witness_beacon.go
@@ -73,7 +73,7 @@ func (p *preimageBeacon) LookupPreimage(payHash []byte) ([]byte, bool) {
 	// the preimage as it's on that we created ourselves.
 	var invoiceKey chainhash.Hash
 	copy(invoiceKey[:], payHash)
-	invoice, err := p.invoices.LookupInvoice(invoiceKey)
+	invoice, _, err := p.invoices.LookupInvoice(invoiceKey)
 	switch {
 	case err == channeldb.ErrInvoiceNotFound:
 		// If we get this error, then it simply means that this invoice