From bea0ffdf81f2697eb0c2b9d84462edb62085fa5a Mon Sep 17 00:00:00 2001
From: yyforyongyu <yy2452@columbia.edu>
Date: Wed, 26 Jul 2023 10:48:00 +0200
Subject: [PATCH] chainfee: add new unit `SatPerVByte`

---
 lnwallet/chainfee/rates.go      | 18 ++++++++++++++++++
 lnwallet/chainfee/rates_test.go | 22 ++++++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 lnwallet/chainfee/rates_test.go

diff --git a/lnwallet/chainfee/rates.go b/lnwallet/chainfee/rates.go
index f9b606f74..34da55374 100644
--- a/lnwallet/chainfee/rates.go
+++ b/lnwallet/chainfee/rates.go
@@ -18,6 +18,24 @@ const (
 	AbsoluteFeePerKwFloor SatPerKWeight = 250
 )
 
+// SatPerVByte represents a fee rate in sat/vbyte.
+type SatPerVByte btcutil.Amount
+
+// FeePerKWeight converts the current fee rate from sat/vb to sat/kw.
+func (s SatPerVByte) FeePerKWeight() SatPerKWeight {
+	return SatPerKWeight(s * 1000 / blockchain.WitnessScaleFactor)
+}
+
+// FeePerKVByte converts the current fee rate from sat/vb to sat/kvb.
+func (s SatPerVByte) FeePerKVByte() SatPerKVByte {
+	return SatPerKVByte(s * 1000)
+}
+
+// String returns a human-readable string of the fee rate.
+func (s SatPerVByte) String() string {
+	return fmt.Sprintf("%v sat/vb", int64(s))
+}
+
 // SatPerKVByte represents a fee rate in sat/kb.
 type SatPerKVByte btcutil.Amount
 
diff --git a/lnwallet/chainfee/rates_test.go b/lnwallet/chainfee/rates_test.go
new file mode 100644
index 000000000..11aa35adf
--- /dev/null
+++ b/lnwallet/chainfee/rates_test.go
@@ -0,0 +1,22 @@
+package chainfee
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestSatPerVByteConversion checks that the conversion from sat/vb to either
+// sat/kw or sat/kvb is correct.
+func TestSatPerVByteConversion(t *testing.T) {
+	t.Parallel()
+
+	// Create a test fee rate of 1 sat/vb.
+	rate := SatPerVByte(1)
+
+	// 1 sat/vb should be equal to 1000 sat/kvb.
+	require.Equal(t, SatPerKVByte(1000), rate.FeePerKVByte())
+
+	// 1 sat/vb should be equal to 250 sat/kw.
+	require.Equal(t, SatPerKWeight(250), rate.FeePerKWeight())
+}