Allow naming without an artist folder and per-folder naming rules

The artist folder can be left empty for Album/01 Title (no artist tag
needed), and folders such as Video Games can have their own formats.
Files in a rule folder are only renamed inside it; other files are never
moved into it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -105,6 +105,11 @@ use the folder image. A replaced `cover.jpg` goes to quarantine, and every chang
 **Organize (rename files from tags).** The *Organize* tab sets how files are named, in the style of Lidarr: an **artist folder**, an
 **album folder**, a **track format** and a separate **multi-disc track format**, with presets. The default is
 `{Artist Name}/{Album Title}/{track:00} {Track Title}`, and multi-disc albums get `{Medium Format} {medium:00}/…` → `Disc 01`, `Disc 02`.
+Leave the artist folder empty for `Album/01 Title`; songs then don't need an artist tag.
+
+**Folders with their own naming.** Part of a library can use different formats, such as game soundtracks in
+`Video Games/{Album Title}/{track:00} {Track Title}` while the rest stays `Artist/Album/01 Title`. Files inside such a folder are only
+renamed within it, and other files are never moved into it (they are skipped with a reason instead). Folder rules can't be nested.
 
 Tokens: `{Artist Name}`, `{Artist NameThe}` (The Beatles → Beatles, The), `{Artist CleanName}`, `{Artist NameFirstCharacter}`,
 `{Album Title}`, `{Album TitleThe}`, `{Album CleanTitle}`, `{Release Year}`, `{track:0}`/`{track:00}`, `{medium:0}`/`{medium:00}`,

internal/api/server.go

@@ -824,7 +824,8 @@ func (s *Server) preAction(w http.ResponseWriter, r *http.Request, pairID int64,
 // ---- organizer ----
 
 func (s *Server) handleNamingInfo(w http.ResponseWriter, r *http.Request) {
-	writeJSON(w, 200, map[string]any{"defaults": engine.DefaultNaming(), "presets": engine.NamingPresets, "tokens": engine.TokenHelp})
+	writeJSON(w, 200, map[string]any{"defaults": engine.DefaultNaming(), "presets": engine.NamingPresets, "tokens": engine.TokenHelp,
+		"folder_default": engine.SoundtrackFolder})
 }
 
 // handleNamingExamples renders sample songs with unsaved settings, using the

internal/engine/naming.go

@@ -18,6 +18,7 @@ import (
 // track format (with a separate format for multi-disc albums), built from
 // tokens such as {Artist Name}, {Album Title} and {track:00}.
 
+// An empty ArtistFolder means no artist folder: Album/01 Title.
 type NamingConfig struct {
 	ArtistFolder    string `json:"artist_folder"`
 	AlbumFolder     string `json:"album_folder"`
@@ -25,6 +26,45 @@ type NamingConfig struct {
 	MultiDiscFormat string `json:"multi_disc_format"`
 	Colon           string `json:"colon"`   // smart, delete, dash, space_dash, space_dash_space
 	Illegal         string `json:"illegal"` // replace or remove
+	// Folders give part of a library its own formats, such as soundtracks in
+	// "Video Games" named Album/01 Title. Files inside such a folder stay
+	// inside it, and other files are never moved into it.
+	Folders []FolderNaming `json:"folders"`
+}
+
+// FolderNaming is the naming for one folder of a library (relative to its root).
+type FolderNaming struct {
+	Folder          string `json:"folder"`
+	ArtistFolder    string `json:"artist_folder"`
+	AlbumFolder     string `json:"album_folder"`
+	TrackFormat     string `json:"track_format"`
+	MultiDiscFormat string `json:"multi_disc_format"`
+}
+
+// formats are the four path formats in effect for one file.
+type formats struct{ artist, album, track, multiDisc string }
+
+func (c NamingConfig) formats() formats {
+	return formats{c.ArtistFolder, c.AlbumFolder, c.TrackFormat, c.MultiDiscFormat}
+}
+
+func (f FolderNaming) formats() formats {
+	return formats{f.ArtistFolder, f.AlbumFolder, f.TrackFormat, f.MultiDiscFormat}
+}
+
+// folderOf returns the folder rule a library path falls under, if any.
+func (c NamingConfig) folderOf(rel string) (FolderNaming, bool) {
+	for _, f := range c.Folders {
+		if inFolder(rel, f.Folder) {
+			return f, true
+		}
+	}
+	return FolderNaming{}, false
+}
+
+// inFolder reports whether rel is inside folder (compared case-insensitively).
+func inFolder(rel, folder string) bool {
+	return strings.HasPrefix(strings.ToLower(rel)+"/", strings.ToLower(folder)+"/") && len(rel) > len(folder)
 }
 
 func DefaultNaming() NamingConfig {
@@ -35,9 +75,14 @@ func DefaultNaming() NamingConfig {
 		MultiDiscFormat: "{Medium Format} {medium:00}/{track:00} {Track Title}",
 		Colon:           "smart",
 		Illegal:         "replace",
+		Folders:         []FolderNaming{},
 	}
 }
 
+// SoundtrackFolder is the suggested folder rule for game and film soundtracks.
+var SoundtrackFolder = FolderNaming{Folder: "Video Games", AlbumFolder: "{Album Title}",
+	TrackFormat: "{track:00} {Track Title}", MultiDiscFormat: "{Medium Format} {medium:00}/{track:00} {Track Title}"}
+
 // NamingPresets are offered in the UI.
 var NamingPresets = []struct {
 	Name   string       `json:"name"`
@@ -51,6 +96,8 @@ var NamingPresets = []struct {
 		MultiDiscFormat: "{Artist Name} - {Album Title} - {medium:00}-{track:00} - {Track Title}", Colon: "smart", Illegal: "replace"}},
 	{"Artist/Album/1-01 Title (disc in name)", NamingConfig{ArtistFolder: "{Artist Name}", AlbumFolder: "{Album Title}",
 		TrackFormat: "{track:00} {Track Title}", MultiDiscFormat: "{medium:0}-{track:00} {Track Title}", Colon: "smart", Illegal: "replace"}},
+	{"Album/01 Title (no artist folder)", NamingConfig{AlbumFolder: "{Album Title}",
+		TrackFormat: "{track:00} {Track Title}", MultiDiscFormat: "{Medium Format} {medium:00}/{track:00} {Track Title}", Colon: "smart", Illegal: "replace"}},
 }
 
 // NamingOf returns a pair's naming, converting the settings of earlier
@@ -58,9 +105,7 @@ var NamingPresets = []struct {
 func NamingOf(p store.Pair) NamingConfig {
 	c := DefaultNaming()
 	if len(p.OrganizeConfig) > 0 && string(p.OrganizeConfig) != "{}" {
-		var stored NamingConfig
-		if json.Unmarshal(p.OrganizeConfig, &stored) == nil {
-			fill(&stored, c)
+		if stored, err := parseNaming(p.OrganizeConfig); err == nil {
 			return stored
 		}
 	}
@@ -91,9 +136,29 @@ func NamingOf(p store.Pair) NamingConfig {
 	return c
 }
 
+// parseNaming reads stored settings. Fields missing from the JSON take the
+// defaults; an artist folder that is present but empty stays empty.
+func parseNaming(raw []byte) (NamingConfig, error) {
+	c := DefaultNaming()
+	if err := json.Unmarshal(raw, &c); err != nil {
+		return c, err
+	}
+	fill(&c, DefaultNaming())
+	return c, nil
+}
+
 func fill(c *NamingConfig, d NamingConfig) {
-	if strings.TrimSpace(c.ArtistFolder) == "" {
-		c.ArtistFolder = d.ArtistFolder
+	c.ArtistFolder = strings.TrimSpace(c.ArtistFolder)
+	if c.Folders == nil {
+		c.Folders = []FolderNaming{}
+	}
+	for i := range c.Folders {
+		f := &c.Folders[i]
+		f.Folder = strings.Trim(strings.TrimSpace(f.Folder), "/")
+		f.ArtistFolder = strings.TrimSpace(f.ArtistFolder)
+		if strings.TrimSpace(f.MultiDiscFormat) == "" {
+			f.MultiDiscFormat = "{Medium Format} {medium:00}/" + f.TrackFormat
+		}
 	}
 	if strings.TrimSpace(c.AlbumFolder) == "" {
 		c.AlbumFolder = d.AlbumFolder
@@ -171,42 +236,32 @@ func styleOf(t string) (sep string, cased string) {
 
 // ValidateNaming checks the formats.
 func ValidateNaming(c NamingConfig) error {
-	check := func(label, f string, folder bool) error {
-		if strings.TrimSpace(f) == "" {
-			return fmt.Errorf("%s is empty", label)
-		}
-		if strings.Contains(f, "..") || strings.Contains(f, "\\") || strings.HasPrefix(f, "/") || strings.HasSuffix(f, "/") {
-			return fmt.Errorf("%s must be a relative name without .. or backslashes", label)
-		}
-		if folder && strings.Contains(f, "/") {
-			return fmt.Errorf("%s must be a single folder name (no /)", label)
-		}
-		for _, m := range tokenPat.FindAllStringSubmatch(f, -1) {
-			if numberTok.MatchString(m[1]) {
-				continue
-			}
-			if !knownTokens[tokenKey(m[1])] {
-				return fmt.Errorf("%s: unknown token {%s}", label, m[1])
-			}
-		}
-		if strings.Count(f, "{") != strings.Count(f, "}") {
-			return fmt.Errorf("%s has an unclosed {", label)
-		}
-		return nil
-	}
-	if err := check("Artist folder format", c.ArtistFolder, true); err != nil {
+	if err := checkFormats("", c.formats()); err != nil {
 		return err
 	}
-	if err := check("Album folder format", c.AlbumFolder, true); err != nil {
-		return err
-	}
-	for _, f := range []struct{ label, v string }{{"Track format", c.TrackFormat}, {"Multi-disc track format", c.MultiDiscFormat}} {
-		if err := check(f.label, f.v, false); err != nil {
+	seen := map[string]bool{}
+	for _, f := range c.Folders {
+		label := fmt.Sprintf("Folder %q", f.Folder)
+		switch {
+		case f.Folder == "":
+			return errors.New("a folder rule has no folder")
+		case strings.Contains(f.Folder, "\\") || strings.HasPrefix(f.Folder, "/") || filepath.Clean(f.Folder) != f.Folder ||
+			f.Folder == "." || strings.HasPrefix(f.Folder, ".."):
+			return fmt.Errorf("%s must be a folder inside the library, like Video Games", label)
+		case strings.HasPrefix(filepath.Base(f.Folder), "."):
+			return fmt.Errorf("%s: hidden folders can't have naming rules", label)
+		case seen[strings.ToLower(f.Folder)]:
+			return fmt.Errorf("%s is listed twice", label)
+		}
+		seen[strings.ToLower(f.Folder)] = true
+		for _, o := range c.Folders {
+			if inFolder(f.Folder, o.Folder) {
+				return fmt.Errorf("%s is inside %q; folder rules can't be nested", label, o.Folder)
+			}
+		}
+		if err := checkFormats(label+": ", f.formats()); err != nil {
 			return err
 		}
-		if !strings.Contains(tokenKeys(f.v), "|tracktitle|") && !strings.Contains(tokenKeys(f.v), "|trackcleantitle|") {
-			return fmt.Errorf("%s must contain {Track Title}", f.label)
-		}
 	}
 	switch c.Colon {
 	case "smart", "delete", "dash", "space_dash", "space_dash_space":
@@ -219,6 +274,51 @@ func ValidateNaming(c NamingConfig) error {
 	return nil
 }
 
+// checkFormats validates one set of formats. The artist folder may be empty.
+func checkFormats(prefix string, f formats) error {
+	if f.artist != "" {
+		if err := checkFormat(prefix+"Artist folder format", f.artist, true); err != nil {
+			return err
+		}
+	}
+	if err := checkFormat(prefix+"Album folder format", f.album, true); err != nil {
+		return err
+	}
+	for _, t := range []struct{ label, v string }{{"Track format", f.track}, {"Multi-disc track format", f.multiDisc}} {
+		if err := checkFormat(prefix+t.label, t.v, false); err != nil {
+			return err
+		}
+		if !strings.Contains(tokenKeys(t.v), "|tracktitle|") && !strings.Contains(tokenKeys(t.v), "|trackcleantitle|") {
+			return fmt.Errorf("%s%s must contain {Track Title}", prefix, t.label)
+		}
+	}
+	return nil
+}
+
+func checkFormat(label, f string, folder bool) error {
+	if strings.TrimSpace(f) == "" {
+		return fmt.Errorf("%s is empty", label)
+	}
+	if strings.Contains(f, "..") || strings.Contains(f, "\\") || strings.HasPrefix(f, "/") || strings.HasSuffix(f, "/") {
+		return fmt.Errorf("%s must be a relative name without .. or backslashes", label)
+	}
+	if folder && strings.Contains(f, "/") {
+		return fmt.Errorf("%s must be a single folder name (no /)", label)
+	}
+	for _, m := range tokenPat.FindAllStringSubmatch(f, -1) {
+		if numberTok.MatchString(m[1]) {
+			continue
+		}
+		if !knownTokens[tokenKey(m[1])] {
+			return fmt.Errorf("%s: unknown token {%s}", label, m[1])
+		}
+	}
+	if strings.Count(f, "{") != strings.Count(f, "}") {
+		return fmt.Errorf("%s has an unclosed {", label)
+	}
+	return nil
+}
+
 func tokenKeys(f string) string {
 	var b strings.Builder
 	b.WriteString("|")
@@ -350,30 +450,62 @@ func valuesOf(f map[string]string) songValues {
 
 func (v songValues) multiDisc() bool { return v.discTotal > 1 || v.disc > 1 }
 
-// renderPath builds the organized relative path of a song. It returns the
-// missing tag when a required one is empty.
-func renderPath(c NamingConfig, ext string, f map[string]string) (string, string) {
+// renderPath builds the organized relative path of a song at rel. Songs in
+// a folder with its own naming stay in that folder. It returns why the song
+// can't be renamed instead when a tag is missing or the new path would enter
+// a folder that has its own naming.
+func renderPath(c NamingConfig, rel string, f map[string]string) (string, string) {
+	ext := filepath.Ext(rel)
+	if rule, ok := c.folderOf(rel); ok {
+		to, why := renderFormats(c, rule.formats(), ext, f)
+		if why != "" {
+			return "", why
+		}
+		// Keep the folder as it is spelled on disk.
+		return filepath.Join(rel[:len(rule.Folder)], to), ""
+	}
+	to, why := renderFormats(c, c.formats(), ext, f)
+	if why != "" {
+		return "", why
+	}
+	for _, rule := range c.Folders {
+		if inFolder(to, rule.Folder) {
+			return "", "would move into " + rule.Folder + ", which has its own naming"
+		}
+	}
+	return to, ""
+}
+
+var artistTokens = []string{"|artistname|", "|artistnamethe|", "|artistcleanname|", "|artistnamefirstcharacter|"}
+
+func renderFormats(c NamingConfig, fm formats, ext string, f map[string]string) (string, string) {
 	v := valuesOf(f)
-	if v.artist == "" {
-		return "", "artist or album artist"
+	track := fm.track
+	if v.multiDisc() {
+		track = fm.multiDisc
+	}
+	used := tokenKeys(fm.artist + fm.album + track)
+	for _, t := range artistTokens {
+		if v.artist == "" && strings.Contains(used, t) {
+			return "", "missing artist or album artist tag"
+		}
 	}
 	if v.album == "" {
-		return "", "album"
+		return "", "missing album tag"
 	}
 	if v.title == "" {
-		return "", "title"
-	}
-	track := c.TrackFormat
-	if v.multiDisc() {
-		track = c.MultiDiscFormat
+		return "", "missing title tag"
 	}
 	var parts []string
-	for _, f := range []string{c.ArtistFolder, c.AlbumFolder, track} {
+	for _, f := range []string{fm.artist, fm.album, track} {
+		if f == "" {
+			continue // no artist folder
+		}
 		for _, part := range strings.Split(f, "/") {
 			out := tokenPat.ReplaceAllStringFunc(part, func(tok string) string { return renderToken(tok[1:len(tok)-1], v, c) })
 			out = finishComponent(out)
 			if out == "" {
-				return "", "tags for " + part
+				return "", "missing tags for " + part
 			}
 			parts = append(parts, out)
 		}
@@ -465,12 +597,19 @@ func NamingExamples(c NamingConfig) []NamingExample {
 			tags.Track: "7", tags.Date: "1986"}},
 	}
 	out := []NamingExample{}
-	for _, s := range samples {
-		p, missing := renderPath(c, s.ext, s.f)
-		if missing != "" {
-			p = "(skipped: missing " + missing + ")"
+	add := func(label, rel string, f map[string]string) {
+		p, why := renderPath(c, rel, f)
+		if why != "" {
+			p = "(skipped: " + why + ")"
 		}
-		out = append(out, NamingExample{Label: s.label, Path: p})
+		out = append(out, NamingExample{Label: label, Path: p})
+	}
+	for _, s := range samples {
+		add(s.label, "x"+s.ext, s.f)
+	}
+	for _, rule := range c.Folders {
+		add("In "+rule.Folder, rule.Folder+"/x.flac", map[string]string{tags.Artist: "Koji Kondo", tags.Album: "Super Mario Galaxy",
+			tags.Title: "Gusty Garden Galaxy", tags.Track: "3", tags.Date: "2007"})
 	}
 	return out
 }

internal/engine/naming_test.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"os"
 	"path/filepath"
+	"reflect"
+	"strings"
 	"testing"
 
 	"github.com/cdnutter/playlink/internal/store"
@@ -57,7 +59,7 @@ func TestRenderPath(t *testing.T) {
 		{"no hidden names", d, song("artist", "...And Justice", "album", "B", "title", "S", "track", "1"), ".mp3", "And Justice/B/01 S.mp3"},
 	}
 	for _, c := range cases {
-		got, missing := renderPath(c.c, c.ext, c.f)
+		got, missing := renderPath(c.c, "in/x"+c.ext, c.f)
 		if got != c.want || missing != "" {
 			t.Errorf("%s: got %q (missing %q), want %q", c.name, got, missing, c.want)
 		}
@@ -67,12 +69,82 @@ func TestRenderPath(t *testing.T) {
 		"album":                  song("artist", "A", "title", "S"),
 		"title":                  song("artist", "A", "album", "B"),
 	} {
-		if _, missing := renderPath(d, ".mp3", f); missing != field {
-			t.Errorf("want missing %q, got %q", field, missing)
+		if _, why := renderPath(d, "x.mp3", f); why != "missing "+field+" tag" {
+			t.Errorf("want missing %q, got %q", field, why)
 		}
 	}
 }
 
+func TestNamingWithoutArtistFolder(t *testing.T) {
+	c := DefaultNaming()
+	c.ArtistFolder = ""
+	if err := ValidateNaming(c); err != nil {
+		t.Fatal(err)
+	}
+	// Soundtracks often have no artist tag; it isn't needed without the folder.
+	got, why := renderPath(c, "x.flac", song("album", "Super Mario Galaxy", "title", "Gusty Garden Galaxy", "track", "3"))
+	if got != "Super Mario Galaxy/03 Gusty Garden Galaxy.flac" || why != "" {
+		t.Fatalf("got %q %q", got, why)
+	}
+	got, _ = renderPath(c, "x.flac", song("album", "Halo 3", "title", "S", "track", "2", "disc", "2/2"))
+	if got != "Halo 3/Disc 02/02 S.flac" {
+		t.Fatalf("multi-disc: %q", got)
+	}
+	// Saving an empty artist folder keeps it empty; a missing one takes the default.
+	raw, _ := json.Marshal(c)
+	if got := NamingOf(store.Pair{OrganizeConfig: raw}); got.ArtistFolder != "" {
+		t.Fatalf("empty artist folder should stay empty: %+v", got)
+	}
+	p := store.Pair{OrganizeConfig: raw}
+	if err := normalizeOrganize(&p); err != nil || NamingOf(p).ArtistFolder != "" {
+		t.Fatalf("normalize: %v %s", err, p.OrganizeConfig)
+	}
+}
+
+func TestNamingFolderRules(t *testing.T) {
+	c := DefaultNaming()
+	c.Folders = []FolderNaming{SoundtrackFolder}
+	if err := ValidateNaming(c); err != nil {
+		t.Fatal(err)
+	}
+	vgm := song("artist", "Koji Kondo", "album", "Super Mario Galaxy", "title", "Gusty Garden Galaxy", "track", "3")
+	cases := []struct{ rel, want, why string }{
+		{"Video Games/mario/gusty.flac", "Video Games/Super Mario Galaxy/03 Gusty Garden Galaxy.flac", ""},
+		{"video games/Mario/x.flac", "video games/Super Mario Galaxy/03 Gusty Garden Galaxy.flac", ""}, // spelled as on disk
+		{"Koji Kondo/x.flac", "Koji Kondo/Super Mario Galaxy/03 Gusty Garden Galaxy.flac", ""},
+		{"Video Games Extra/x.flac", "Koji Kondo/Super Mario Galaxy/03 Gusty Garden Galaxy.flac", ""},
+	}
+	for _, tc := range cases {
+		got, why := renderPath(c, tc.rel, vgm)
+		if got != tc.want || why != tc.why {
+			t.Errorf("%s: got %q %q, want %q", tc.rel, got, why, tc.want)
+		}
+	}
+	// A file outside the folder is never moved into it.
+	if _, why := renderPath(c, "x.flac", song("artist", "Video Games", "album", "B", "title", "S")); !strings.Contains(why, "own naming") {
+		t.Fatalf("should refuse to move into the rule folder: %q", why)
+	}
+	bad := []FolderNaming{
+		{Folder: "", AlbumFolder: "{Album Title}", TrackFormat: "{Track Title}", MultiDiscFormat: "{Track Title}"},
+		{Folder: "../x", AlbumFolder: "{Album Title}", TrackFormat: "{Track Title}", MultiDiscFormat: "{Track Title}"},
+		{Folder: ".playlink-trash", AlbumFolder: "{Album Title}", TrackFormat: "{Track Title}", MultiDiscFormat: "{Track Title}"},
+		{Folder: "Video Games/Nintendo", AlbumFolder: "{Album Title}", TrackFormat: "{Track Title}", MultiDiscFormat: "{Track Title}"},
+		{Folder: "VIDEO GAMES", AlbumFolder: "{Album Title}", TrackFormat: "{Track Title}", MultiDiscFormat: "{Track Title}"},
+		{Folder: "OST", AlbumFolder: "{Album Title}", TrackFormat: "{track:00}", MultiDiscFormat: "{Track Title}"},
+	}
+	for _, b := range bad {
+		cc := c
+		cc.Folders = []FolderNaming{SoundtrackFolder, b}
+		if ValidateNaming(cc) == nil {
+			t.Errorf("rule %+v should be rejected", b)
+		}
+	}
+	ex := NamingExamples(c)
+	if last := ex[len(ex)-1]; last.Label != "In Video Games" || last.Path != "Video Games/Super Mario Galaxy/03 Gusty Garden Galaxy.flac" {
+		t.Fatalf("folder example: %+v", last)
+	}
+}
+
 func TestValidateNaming(t *testing.T) {
 	bad := []func(*NamingConfig){
 		func(c *NamingConfig) { c.ArtistFolder = "{Artist Name}/{Album Title}" },
@@ -103,11 +175,10 @@ func TestNamingOfConvertsOldSettings(t *testing.T) {
 		c.MultiDiscFormat != "{medium:0}-{track:00} - {Track Title}" {
 		t.Fatalf("old settings not converted: %+v", c)
 	}
-	if got := NamingOf(store.Pair{}); got != DefaultNaming() {
+	if got := NamingOf(store.Pair{}); !reflect.DeepEqual(got, DefaultNaming()) {
 		t.Fatalf("pairs without settings should use the defaults, got %+v", got)
 	}
-	raw, _ := json.Marshal(NamingConfig{TrackFormat: "{track:0}. {Track Title}"})
-	got := NamingOf(store.Pair{OrganizeConfig: raw})
+	got := NamingOf(store.Pair{OrganizeConfig: []byte(`{"track_format":"{track:0}. {Track Title}"}`)})
 	if got.TrackFormat != "{track:0}. {Track Title}" || got.ArtistFolder != "{Artist Name}" {
 		t.Fatalf("stored settings should win and gaps take defaults, got %+v", got)
 	}
@@ -154,3 +225,29 @@ func TestRenameNowPreviewAndApply(t *testing.T) {
 		t.Fatal("applying without a fresh preview must be refused")
 	}
 }
+
+func TestOrganizeFolderRule(t *testing.T) {
+	ev := tagEnv(t, false)
+	c := DefaultNaming()
+	c.Folders = []FolderNaming{SoundtrackFolder}
+	ev.pair.OrganizeConfig, _ = json.Marshal(c)
+	if err := ev.st.SavePair(ctx, &ev.pair); err != nil {
+		t.Fatal(err)
+	}
+	mkTagged(t, filepath.Join(ev.slave, "Video Games/rip/g.flac"), "title", "Gusty Garden Galaxy", "album", "Super Mario Galaxy", "track", "3")
+	mkTagged(t, filepath.Join(ev.slave, "Video Games/Halo 3/01 Halo.flac"), "title", "Halo", "artist", "Martin O'Donnell", "album", "Halo 3", "track", "1")
+	mkTagged(t, filepath.Join(ev.slave, "in/a.mp3"), "title", "One", "artist", "Band", "album", "LP", "track", "1")
+	ev.e.StartOrganizePreview(ev.pair.ID, "slave")
+	ev.wait()
+	plan, items := ev.e.OrganizePreview(ev.pair.ID)
+	if plan == nil || plan.Moves != 2 || plan.Conforming != 1 {
+		t.Fatalf("preview: %+v %+v", plan, items)
+	}
+	ev.e.StartOrganizeApply(ev.pair.ID, nil)
+	ev.wait()
+	for _, rel := range []string{"Video Games/Super Mario Galaxy/03 Gusty Garden Galaxy.flac", "Video Games/Halo 3/01 Halo.flac", "Band/LP/01 One.mp3"} {
+		if _, err := os.Stat(filepath.Join(ev.slave, rel)); err != nil {
+			t.Error(err)
+		}
+	}
+}

internal/engine/organize.go

@@ -29,11 +29,10 @@ import (
 // normalizeOrganize validates a pair's organize settings.
 func normalizeOrganize(p *store.Pair) error {
 	if len(p.OrganizeConfig) > 0 && string(p.OrganizeConfig) != "{}" && string(p.OrganizeConfig) != "null" {
-		var c NamingConfig
-		if err := json.Unmarshal(p.OrganizeConfig, &c); err != nil {
+		c, err := parseNaming(p.OrganizeConfig)
+		if err != nil {
 			return fmt.Errorf("naming settings: %w", err)
 		}
-		fill(&c, DefaultNaming())
 		if err := ValidateNaming(c); err != nil {
 			return err
 		}
@@ -171,8 +170,8 @@ func (e *Engine) planOrganize(ctx context.Context, j *Job, l *libs, sides []stri
 				item.Reason = "file type without editable tags"
 			} else if fields, err := e.tagCache.get(ctx, e.tagTools, filepath.Join(root.Path, rel), in); err != nil {
 				item.Reason = "tags could not be read"
-			} else if to, missing := renderPath(naming, filepath.Ext(rel), fields); missing != "" {
-				item.Reason = "missing " + missing + " tag"
+			} else if to, why := renderPath(naming, rel, fields); why != "" {
+				item.Reason = why
 			} else if to == rel {
 				plan.Conforming++
 				continue

web/src/api.ts

@@ -249,6 +249,16 @@ export type Naming = {
   multi_disc_format: string;
   colon: "smart" | "delete" | "dash" | "space_dash" | "space_dash_space";
   illegal: "replace" | "remove";
+  folders: FolderNaming[];
+};
+
+/** Its own naming for one folder of a library, e.g. soundtracks in "Video Games". */
+export type FolderNaming = {
+  folder: string;
+  artist_folder: string;
+  album_folder: string;
+  track_format: string;
+  multi_disc_format: string;
 };
 
 export type OrganizeItem = { id: number; side: Side; from: string; to?: string; move: boolean; reason?: string; sidecars?: string[] };

web/src/pages/Organize.tsx

@@ -1,18 +1,21 @@
 import { useEffect, useMemo, useRef, useState } from "react";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
-import { AlertTriangle, ArrowRight, ChevronDown, ChevronRight, Folder, FolderTree, Tags as TagsIcon } from "lucide-react";
-import { api, type Job, type Naming, type OrganizeItem, type OrganizePlan, type Pair, type Side } from "../api";
+import { AlertTriangle, ArrowRight, ChevronDown, ChevronRight, Folder, FolderPlus, FolderTree, Tags as TagsIcon, Trash2 } from "lucide-react";
+import { api, type FolderNaming, type Job, type Naming, type OrganizeItem, type OrganizePlan, type Pair, type Side } from "../api";
 import { useInfo } from "../App";
 import { Alert, Badge, Button, Card, Field, Modal, Spinner, cx, inputCls } from "../ui";
 import { useToast } from "../toast";
 import { TagEditor } from "./Tags";
 
-type NamingInfo = { defaults: Naming; presets: { name: string; config: Naming }[]; tokens: [string, string][] };
+type NamingInfo = { defaults: Naming; presets: { name: string; config: Naming }[]; tokens: [string, string][]; folder_default: FolderNaming };
+type FormatKey = "artist_folder" | "album_folder" | "track_format" | "multi_disc_format";
+// Where a token is inserted: a main format, or one of a folder rule's (rule = its index).
+type FieldRef = { rule: number | null; key: FormatKey; el: HTMLInputElement };
 type Scope = Side | "both";
 
-const FORMAT_FIELDS: { key: keyof Naming; label: string; hint: string }[] = [
-  { key: "artist_folder", label: "Artist folder", hint: "One folder name." },
-  { key: "album_folder", label: "Album folder", hint: "One folder name, inside the artist folder." },
+const FORMAT_FIELDS: { key: FormatKey; label: string; hint: string }[] = [
+  { key: "artist_folder", label: "Artist folder", hint: "One folder name. Leave empty for no artist folder (Album/01 Title)." },
+  { key: "album_folder", label: "Album folder", hint: "One folder name, inside the artist folder if there is one." },
   { key: "track_format", label: "Track", hint: "File name inside the album folder. May add subfolders with /." },
   { key: "multi_disc_format", label: "Multi-disc track", hint: "Used when an album has more than one disc." },
 ];
@@ -38,7 +41,7 @@ function NamingCard({ pair }: { pair: Pair }) {
   const [cfg, setCfg] = useState<Naming>(pair.naming);
   const [auto, setAuto] = useState(pair.auto_organize);
   const [showTokens, setShowTokens] = useState(false);
-  const focused = useRef<{ key: keyof Naming; el: HTMLInputElement } | null>(null);
+  const focused = useRef<FieldRef | null>(null);
   const saved = JSON.stringify(pair.naming);
   useEffect(() => {
     setCfg(pair.naming);
@@ -82,13 +85,16 @@ function NamingCard({ pair }: { pair: Pair }) {
     onError: (e) => toast("err", e.message),
   });
 
+  const folders = cfg.folders ?? [];
+  const setField = (rule: number | null, key: FormatKey, v: string) =>
+    setCfg(rule === null ? { ...cfg, [key]: v } : { ...cfg, folders: folders.map((r, i) => (i === rule ? { ...r, [key]: v } : r)) });
   const insert = (token: string) => {
     const f = focused.current;
     if (!f) return;
-    const v = cfg[f.key] as string;
+    const v = f.rule === null ? cfg[f.key] : (folders[f.rule]?.[f.key] ?? "");
     const start = f.el.selectionStart ?? v.length;
     const end = f.el.selectionEnd ?? v.length;
-    setCfg({ ...cfg, [f.key]: v.slice(0, start) + token + v.slice(end) });
+    setField(f.rule, f.key, v.slice(0, start) + token + v.slice(end));
     requestAnimationFrame(() => {
       f.el.focus();
       f.el.setSelectionRange(start + token.length, start + token.length);
@@ -118,9 +124,9 @@ function NamingCard({ pair }: { pair: Pair }) {
               type="button"
               className={cx(
                 "rounded-md border px-2 py-0.5 mono cursor-pointer",
-                JSON.stringify(p.config) === JSON.stringify(cfg) ? "border-accent bg-accent/15 text-white" : "border-line bg-panel-2 text-gray-300 hover:border-accent",
+                sameFormats(p.config, cfg) ? "border-accent bg-accent/15 text-white" : "border-line bg-panel-2 text-gray-300 hover:border-accent",
               )}
-              onClick={() => setCfg(p.config)}
+              onClick={() => setCfg({ ...p.config, folders })}
             >
               {p.name}
             </button>
@@ -128,24 +134,68 @@ function NamingCard({ pair }: { pair: Pair }) {
         </div>
       )}
 
-      <div className="grid gap-4 md:grid-cols-2">
-        {FORMAT_FIELDS.map((f) => (
-          <Field key={f.key} label={f.label} hint={f.hint}>
-            <input
-              className={inputCls + " mono text-xs"}
-              value={cfg[f.key] as string}
-              spellCheck={false}
-              onFocus={(e) => (focused.current = { key: f.key, el: e.currentTarget })}
-              onChange={(e) => setCfg({ ...cfg, [f.key]: e.target.value })}
+      <FormatFields values={cfg} onChange={(k, v) => setField(null, k, v)} onFocus={(key, el) => (focused.current = { rule: null, key, el })} />
+
+      <div className="space-y-3">
+        <div className="flex flex-wrap items-center justify-between gap-2">
+          <div>
+            <h3 className="text-sm font-medium">Folders with their own naming</h3>
+            <p className="text-xs text-muted">
+              For part of a library that is organized differently, such as game soundtracks in{" "}
+              <span className="mono">Video Games/Album/01 Title</span>. Files in the folder stay in it, and other files are never moved into it.
+            </p>
+          </div>
+          <Button
+            size="sm"
+            onClick={() =>
+              info.data &&
+              setCfg({
+                ...cfg,
+                folders: [...folders, { ...info.data.folder_default, folder: folders.length ? "" : info.data.folder_default.folder }],
+              })
+            }
+          >
+            <FolderPlus className="size-4" /> Add folder
+          </Button>
+        </div>
+        {folders.map((r, i) => (
+          <div key={i} className="space-y-3 rounded-lg border border-line bg-panel-2/40 p-3">
+            <div className="flex items-start gap-2">
+              <div className="flex-1">
+                <Field label="Folder" hint="Relative to the library, e.g. Video Games or Music/Soundtracks.">
+                  <input
+                    className={inputCls + " mono text-xs"}
+                    value={r.folder}
+                    placeholder="Video Games"
+                    spellCheck={false}
+                    onChange={(e) => setCfg({ ...cfg, folders: folders.map((x, j) => (j === i ? { ...x, folder: e.target.value } : x)) })}
+                  />
+                </Field>
+              </div>
+              <Button
+                className="mt-7"
+                variant="ghost"
+                size="sm"
+                title="Remove this folder rule"
+                onClick={() => setCfg({ ...cfg, folders: folders.filter((_, j) => j !== i) })}
+              >
+                <Trash2 className="size-4" />
+              </Button>
+            </div>
+            <FormatFields
+              values={r}
+              inside={r.folder || "the folder"}
+              onChange={(k, v) => setField(i, k, v)}
+              onFocus={(key, el) => (focused.current = { rule: i, key, el })}
             />
-          </Field>
+          </div>
         ))}
       </div>
 
       <div>
         <button className="flex items-center gap-1 text-xs text-muted hover:text-white cursor-pointer" onClick={() => setShowTokens(!showTokens)}>
-          {showTokens ? <ChevronDown className="size-3.5" /> : <ChevronRight className="size-3.5" />} Tokens (click one to insert it into the field you
-          last clicked)
+          {showTokens ? <ChevronDown className="size-3.5" /> : <ChevronRight className="size-3.5" />} Tokens (click one to insert it into the field
+          you last clicked)
         </button>
         {showTokens && info.data && (
           <div className="mt-2 grid gap-1 sm:grid-cols-2 lg:grid-cols-3">
@@ -162,8 +212,8 @@ function NamingCard({ pair }: { pair: Pair }) {
               </button>
             ))}
             <p className="text-[11px] text-muted sm:col-span-2 lg:col-span-3">
-              Write a token with dots or underscores to use them between words (<code className="mono">{"{Artist.Name}"}</code> →
-              Avenged.Sevenfold), or in capitals or lower case to change the case (<code className="mono">{"{ARTIST NAME}"}</code>).
+              Write a token with dots or underscores to use them between words (<code className="mono">{"{Artist.Name}"}</code> → Avenged.Sevenfold),
+              or in capitals or lower case to change the case (<code className="mono">{"{ARTIST NAME}"}</code>).
             </p>
           </div>
         )}
@@ -208,8 +258,8 @@ function NamingCard({ pair }: { pair: Pair }) {
       </div>
       {auto !== "off" && (
         <Alert tone="amber" icon={<AlertTriangle className="mt-0.5 size-4 shrink-0" />}>
-          Files are renamed during each scan without asking. Every rename is in History and can be undone; files with missing tags or clashing
-          names are left alone. Dry run still applies.
+          Files are renamed during each scan without asking. Every rename is in History and can be undone; files with missing tags or clashing names
+          are left alone. Dry run still applies.
         </Alert>
       )}
     </Card>
@@ -305,7 +355,10 @@ function RenameFilesDialog({ pair, scope, onClose }: { pair: Pair; scope: Scope;
   const apply = useMutation({
     mutationFn: () => api.post(`/pairs/${pair.id}/organize/apply`, { ids: sel.size === moves.length ? [] : [...sel] }),
     onSuccess: () => {
-      toast("ok", dry ? "Started (dry run): renames are recorded as planned only" : `Renaming ${sel.size} files. The library is rescanned afterwards.`);
+      toast(
+        "ok",
+        dry ? "Started (dry run): renames are recorded as planned only" : `Renaming ${sel.size} files. The library is rescanned afterwards.`,
+      );
       qc.invalidateQueries({ queryKey: ["pair", pair.id] });
       onClose();
     },
@@ -350,7 +403,10 @@ function RenameFilesDialog({ pair, scope, onClose }: { pair: Pair; scope: Scope;
                 <button
                   key={v}
                   onClick={() => setView(v)}
-                  className={cx("-mb-px border-b-2 px-3 py-1.5 text-sm cursor-pointer", view === v ? "border-accent text-white" : "border-transparent text-muted hover:text-white")}
+                  className={cx(
+                    "-mb-px border-b-2 px-3 py-1.5 text-sm cursor-pointer",
+                    view === v ? "border-accent text-white" : "border-transparent text-muted hover:text-white",
+                  )}
                 >
                   {v === "changes" ? `Changes (${moves.length})` : `Skipped (${skipped.length})`}
                 </button>
@@ -365,7 +421,12 @@ function RenameFilesDialog({ pair, scope, onClose }: { pair: Pair; scope: Scope;
                   type="checkbox"
                   className="accent-violet-500"
                   checked={sel.size === moves.length}
-                  onChange={(e) => toggle(moves.map((m) => m.id), e.target.checked)}
+                  onChange={(e) =>
+                    toggle(
+                      moves.map((m) => m.id),
+                      e.target.checked,
+                    )
+                  }
                 />
                 {sel.size} of {moves.length} selected, in {groups.length} folder{groups.length !== 1 && "s"}
               </label>
@@ -387,8 +448,16 @@ function RenameFilesDialog({ pair, scope, onClose }: { pair: Pair; scope: Scope;
                         {both && <Badge tone={side === "master" ? "violet" : "gray"}>{side}</Badge>}
                       </label>
                       {items.map((it) => (
-                        <label key={it.id} className={cx("flex items-start gap-2 py-1 pl-9 pr-3 text-xs cursor-pointer", !sel.has(it.id) && "opacity-50")}>
-                          <input type="checkbox" className="mt-0.5 accent-violet-500" checked={sel.has(it.id)} onChange={(e) => toggle([it.id], e.target.checked)} />
+                        <label
+                          key={it.id}
+                          className={cx("flex items-start gap-2 py-1 pl-9 pr-3 text-xs cursor-pointer", !sel.has(it.id) && "opacity-50")}
+                        >
+                          <input
+                            type="checkbox"
+                            className="mt-0.5 accent-violet-500"
+                            checked={sel.has(it.id)}
+                            onChange={(e) => toggle([it.id], e.target.checked)}
+                          />
                           <div className="grid min-w-0 flex-1 grid-cols-[1fr_auto_1fr] items-start gap-2 mono">
                             <span className="break-all text-gray-500">{it.from}</span>
                             <ArrowRight className="mt-0.5 size-3 text-muted" />
@@ -442,7 +511,11 @@ function RenameFilesDialog({ pair, scope, onClose }: { pair: Pair; scope: Scope;
               <li>
                 <b className="text-gray-300">Playlists or apps that point at the old paths will need updating.</b>
               </li>
-              {!both && <li>Only the {data.plan.sides[0]} library is renamed; paths may then differ from the other library (hardlinked songs stay paired).</li>}
+              {!both && (
+                <li>
+                  Only the {data.plan.sides[0]} library is renamed; paths may then differ from the other library (hardlinked songs stay paired).
+                </li>
+              )}
               <li>Each rename is in History and can be undone. The library is rescanned when it finishes.</li>
             </ul>
           )}
@@ -472,3 +545,41 @@ function Stat({ label, value, tone }: { label: string; value: number; tone?: str
     </div>
   );
 }
+
+function sameFormats(a: Naming, b: Naming) {
+  return (["artist_folder", "album_folder", "track_format", "multi_disc_format", "colon", "illegal"] as const).every((k) => a[k] === b[k]);
+}
+
+/** The four path formats, for the library or for one folder rule. */
+function FormatFields({
+  values,
+  inside,
+  onChange,
+  onFocus,
+}: {
+  values: Record<FormatKey, string>;
+  inside?: string;
+  onChange: (key: FormatKey, v: string) => void;
+  onFocus: (key: FormatKey, el: HTMLInputElement) => void;
+}) {
+  return (
+    <div className="grid gap-4 md:grid-cols-2">
+      {FORMAT_FIELDS.map((f) => (
+        <Field
+          key={f.key}
+          label={f.label}
+          hint={inside && f.key === "artist_folder" ? `Inside ${inside}. Leave empty for no artist folder.` : f.hint}
+        >
+          <input
+            className={inputCls + " mono text-xs"}
+            value={values[f.key]}
+            placeholder={f.key === "artist_folder" ? "(none)" : undefined}
+            spellCheck={false}
+            onFocus={(e) => onFocus(f.key, e.currentTarget)}
+            onChange={(e) => onChange(f.key, e.target.value)}
+          />
+        </Field>
+      ))}
+    </div>
+  );
+}