From 683093cf9e166043f17ff53767cdfafa09b01ab5 Mon Sep 17 00:00:00 2001
From: Boris Nagaev <bnagaev@gmail.com>
Date: Mon, 22 Apr 2024 13:54:06 -0300
Subject: [PATCH] l402: migration of lsat.token* files

This is needed to preserve old identifiers of nodes that have ever paid
for a Loop or Pool token.
---
 l402/store.go      | 31 ++++++++++++++++++++
 l402/store_test.go | 71 +++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/l402/store.go b/l402/store.go
index ac7d0c1..c7e3c07 100644
--- a/l402/store.go
+++ b/l402/store.go
@@ -69,6 +69,37 @@ func NewFileStore(storeDir string) (*FileStore, error) {
 		}
 	}
 
+	// If token file and pending token file exist under old names and
+	// do not exist under current names, rename them.
+	renames := []struct {
+		oldName, newName string
+	}{
+		{
+			oldName: "lsat.token",
+			newName: storeFileName,
+		},
+		{
+			oldName: "lsat.token.pending",
+			newName: storeFileNamePending,
+		},
+	}
+	for _, rename := range renames {
+		oldPath := filepath.Join(storeDir, rename.oldName)
+		newPath := filepath.Join(storeDir, rename.newName)
+		if _, err := os.Stat(newPath); !errors.Is(err, os.ErrNotExist) {
+			// New file already exists, skipping.
+			continue
+		}
+		if _, err := os.Stat(oldPath); err != nil {
+			// Failed to stat old file, skipping.
+			continue
+		}
+		if err := os.Rename(oldPath, newPath); err != nil {
+			return nil, fmt.Errorf("failed to rename %s to %s: %w",
+				oldPath, newPath, err)
+		}
+	}
+
 	return &FileStore{
 		fileName:        filepath.Join(storeDir, storeFileName),
 		fileNamePending: filepath.Join(storeDir, storeFileNamePending),
diff --git a/l402/store_test.go b/l402/store_test.go
index c62cc6d..2e95a7f 100644
--- a/l402/store_test.go
+++ b/l402/store_test.go
@@ -6,9 +6,10 @@ import (
 	"testing"
 
 	"github.com/lightningnetwork/lnd/lntypes"
+	"github.com/stretchr/testify/require"
 )
 
-// TestStore tests the basic functionality of the file based store.
+// TestFileStore tests the basic functionality of the file based store.
 func TestFileStore(t *testing.T) {
 	t.Parallel()
 
@@ -128,3 +129,71 @@ func TestFileStore(t *testing.T) {
 			errNoReplace)
 	}
 }
+
+// TestFileStorePendingMigration tests migration from lsat.token.pending
+// to l402.token.pending.
+func TestFileStorePendingMigration(t *testing.T) {
+	t.Parallel()
+
+	tempDirName := t.TempDir()
+
+	pendingToken := &Token{
+		Preimage: zeroPreimage,
+		baseMac:  makeMac(),
+	}
+
+	store, err := NewFileStore(tempDirName)
+	require.NoError(t, err)
+
+	// Write a pending token.
+	require.NoError(t, store.StoreToken(pendingToken))
+
+	// Rename file on disk to lsat.token.pending to emulate
+	// a pre-migration state.
+	newPath := filepath.Join(tempDirName, storeFileNamePending)
+	oldPath := filepath.Join(tempDirName, "lsat.token.pending")
+	require.NoError(t, os.Rename(newPath, oldPath))
+
+	// Open the same directory again.
+	store1, err := NewFileStore(tempDirName)
+	require.NoError(t, err)
+
+	// Read the token and compare its value.
+	token, err := store1.CurrentToken()
+	require.NoError(t, err)
+	require.Equal(t, pendingToken.baseMac, token.baseMac)
+}
+
+// TestFileStoreMigration tests migration from lsat.token to l402.token.
+func TestFileStoreMigration(t *testing.T) {
+	t.Parallel()
+
+	tempDirName := t.TempDir()
+
+	paidPreimage := lntypes.Preimage{1, 2, 3, 4, 5}
+	paidToken := &Token{
+		Preimage: paidPreimage,
+		baseMac:  makeMac(),
+	}
+
+	store, err := NewFileStore(tempDirName)
+	require.NoError(t, err)
+
+	// Write a token.
+	require.NoError(t, store.StoreToken(paidToken))
+
+	// Rename file on disk to lsat.token.pending to emulate
+	// a pre-migration state.
+	newPath := filepath.Join(tempDirName, storeFileName)
+	oldPath := filepath.Join(tempDirName, "lsat.token")
+	require.NoError(t, os.Rename(newPath, oldPath))
+
+	// Open the same directory again.
+	store1, err := NewFileStore(tempDirName)
+	require.NoError(t, err)
+
+	// Read the token and compare its value.
+	token, err := store1.CurrentToken()
+	require.NoError(t, err)
+	require.Equal(t, paidToken.baseMac, token.baseMac)
+}