From 8337b5a0b90d41cb8a2825036874d625b6455550 Mon Sep 17 00:00:00 2001
From: Deluan <deluan@navidrome.org>
Date: Sun, 19 Jul 2026 21:44:39 -0400
Subject: [PATCH] feat(scanner): emit legacy PIDs in canonical base62 encoding

---
 model/metadata/legacy_ids.go          | 11 +++++++----
 model/metadata/persistent_ids_test.go |  5 +++++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/model/metadata/legacy_ids.go b/model/metadata/legacy_ids.go
index 18a273550..a54777c26 100644
--- a/model/metadata/legacy_ids.go
+++ b/model/metadata/legacy_ids.go
@@ -9,17 +9,19 @@ import (
 	"github.com/navidrome/navidrome/conf"
 	"github.com/navidrome/navidrome/consts"
 	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/model/id"
 )
 
 // These are the legacy ID functions that were used in the original Navidrome ID generation.
 // They are kept here for backwards compatibility with existing databases.
 
 func legacyTrackID(mf model.MediaFile, prependLibId bool) string {
-	id := mf.Path
+	key := mf.Path
 	if prependLibId && mf.LibraryID != model.DefaultLibraryID {
-		id = fmt.Sprintf("%d\\%s", mf.LibraryID, id)
+		key = fmt.Sprintf("%d\\%s", mf.LibraryID, key)
 	}
-	return fmt.Sprintf("%x", md5.Sum([]byte(id)))
+	sum := md5.Sum([]byte(key))
+	return id.Encode128(sum[:])
 }
 
 func legacyAlbumID(mf model.MediaFile, md Metadata, prependLibId bool) string {
@@ -33,7 +35,8 @@ func legacyAlbumID(mf model.MediaFile, md Metadata, prependLibId bool) string {
 	if prependLibId && mf.LibraryID != model.DefaultLibraryID {
 		albumPath = fmt.Sprintf("%d\\%s", mf.LibraryID, albumPath)
 	}
-	return fmt.Sprintf("%x", md5.Sum([]byte(albumPath)))
+	sum := md5.Sum([]byte(albumPath))
+	return id.Encode128(sum[:])
 }
 
 func legacyMapAlbumArtistName(md Metadata) string {
diff --git a/model/metadata/persistent_ids_test.go b/model/metadata/persistent_ids_test.go
index eb66d11d1..57bb47e08 100644
--- a/model/metadata/persistent_ids_test.go
+++ b/model/metadata/persistent_ids_test.go
@@ -218,6 +218,11 @@ var _ = Describe("getPID", func() {
 	})
 
 	Context("legacy specs", func() {
+		It("emits canonical 22-char base62 ids", func() {
+			mf := model.MediaFile{Path: "/music/a.mp3", LibraryID: 1}
+			// md5("/music/a.mp3") = e3b7fc2ae9447bbec37a13bf916e3cf6 re-encoded as base62
+			Expect(legacyTrackID(mf, false)).To(Equal("6VHl3uR4kss6sUPKA8Cwnk"))
+		})
 		Context("track_legacy", func() {
 			When("library ID is default (1)", func() {
 				It("should not prepend library ID even when prependLibId is true", func() {