From 4da4738a2d3a271e2b9ba6be066f1c38a82de5f7 Mon Sep 17 00:00:00 2001
From: Joost Jager <joost.jager@gmail.com>
Date: Tue, 23 Jun 2020 11:42:12 +0200
Subject: [PATCH] loopdb: persist htlc tx hash

---
 loopdb/store.go      | 31 ++++++++++++++++++++++++++++++-
 loopdb/store_test.go |  9 ++++++++-
 loopdb/swapstate.go  |  8 +++++++-
 3 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/loopdb/store.go b/loopdb/store.go
index 1099ffe..1d48904 100644
--- a/loopdb/store.go
+++ b/loopdb/store.go
@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/coreos/bbolt"
 	"github.com/lightningnetwork/lnd/lntypes"
 )
@@ -48,6 +49,9 @@ var (
 	// basicStateKey contains the serialized basic swap state.
 	basicStateKey = []byte{0}
 
+	// htlcTxHashKey contains the confirmed htlc tx id.
+	htlcTxHashKey = []byte{1}
+
 	// contractKey is the key that stores the serialized swap contract. It
 	// is nested within the sub-bucket for each active swap.
 	//
@@ -284,6 +288,16 @@ func deserializeUpdates(swapBucket *bbolt.Bucket) ([]*LoopEvent, error) {
 			return err
 		}
 
+		// Deserialize htlc tx hash if this updates contains one.
+		htlcTxHashBytes := updateBucket.Get(htlcTxHashKey)
+		if htlcTxHashBytes != nil {
+			htlcTxHash, err := chainhash.NewHash(htlcTxHashBytes)
+			if err != nil {
+				return err
+			}
+			event.HtlcTxHash = htlcTxHash
+		}
+
 		updates = append(updates, event)
 		return nil
 	})
@@ -518,7 +532,22 @@ func (s *boltSwapStore) updateLoop(bucketKey []byte, hash lntypes.Hash,
 			return err
 		}
 
-		return nextUpdateBucket.Put(basicStateKey, updateValue)
+		err = nextUpdateBucket.Put(basicStateKey, updateValue)
+		if err != nil {
+			return err
+		}
+
+		// Write the htlc tx hash if available.
+		if state.HtlcTxHash != nil {
+			err := nextUpdateBucket.Put(
+				htlcTxHashKey, state.HtlcTxHash[:],
+			)
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
 	})
 }
 
diff --git a/loopdb/store_test.go b/loopdb/store_test.go
index 799a1d4..d373876 100644
--- a/loopdb/store_test.go
+++ b/loopdb/store_test.go
@@ -10,10 +10,12 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/coreos/bbolt"
 	"github.com/lightninglabs/loop/test"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/routing/route"
+	"github.com/stretchr/testify/require"
 )
 
 var (
@@ -130,6 +132,10 @@ func testLoopOutStore(t *testing.T, pendingSwap *LoopOutContract) {
 				expectedState, swaps[0].State(),
 			)
 		}
+
+		if expectedState == StatePreimageRevealed {
+			require.NotNil(t, swaps[0].State().HtlcTxHash)
+		}
 	}
 
 	hash := pendingSwap.Preimage.Hash()
@@ -152,7 +158,8 @@ func testLoopOutStore(t *testing.T, pendingSwap *LoopOutContract) {
 	err = store.UpdateLoopOut(
 		hash, testTime,
 		SwapStateData{
-			State: StatePreimageRevealed,
+			State:      StatePreimageRevealed,
+			HtlcTxHash: &chainhash.Hash{1, 6, 2},
 		},
 	)
 	if err != nil {
diff --git a/loopdb/swapstate.go b/loopdb/swapstate.go
index c463966..1227f16 100644
--- a/loopdb/swapstate.go
+++ b/loopdb/swapstate.go
@@ -1,6 +1,9 @@
 package loopdb
 
-import "github.com/btcsuite/btcutil"
+import (
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcutil"
+)
 
 // SwapState indicates the current state of a swap. This enumeration is the
 // union of loop in and loop out states. A single type is used for both swap
@@ -147,4 +150,7 @@ type SwapStateData struct {
 
 	// Cost are the accrued (final) costs so far.
 	Cost SwapCost
+
+	// HtlcTxHash is the tx id of the confirmed htlc.
+	HtlcTxHash *chainhash.Hash
 }