refactor: the server says a count one way, words.Count, for notifications, a wanted match's reason and the duplicate resolver's activity line (M505 #5643)

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

internal/library/duplicate_resolve.go

@@ -15,6 +15,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/notifications"
 	syncpkg "git.fabledsword.com/bvandeusen/minstrel/internal/sync"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/words"
 )
 
 // Duplicate resolver (M498 #5435, #5437; M502 #5517).
@@ -177,7 +178,7 @@ func ResolveDuplicates(
 	if res.Merged > 0 {
 		notifyAdmins(ctx, notifications.KindDuplicatesResolved, notifications.Payload{
 			Count:  int64(res.Merged),
-			Detail: fmt.Sprintf("Merged %d duplicate %s.", res.Merged, pluralWord(res.Merged, "copy", "copies")),
+			Detail: "Merged " + words.Count(res.Merged, "duplicate copy", "duplicate copies") + ".",
 		})
 	}
 	return res, nil
@@ -351,13 +352,6 @@ func autoMerge(
 	return nil
 }
 
-func pluralWord(n int, one, many string) string {
-	if n == 1 {
-		return one
-	}
-	return many
-}
-
 // DuplicateResolveWorker runs a resolver pass every hour.
 type DuplicateResolveWorker struct {
 	pool     *pgxpool.Pool

internal/notifications/render.go

@@ -3,6 +3,8 @@ package notifications
 import (
 	"encoding/json"
 	"fmt"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/words"
 )
 
 // Rendered is a notification as people read it. The server renders it once,
@@ -138,13 +140,10 @@ func Render(kind Kind, payload []byte) Rendered {
 }
 
 func plural(n int64, one, many string) string {
-	if n == 1 {
-		return "1 " + one
-	}
 	if n < 1 {
 		// A coalesced kind always carries a count; this only guards a
 		// malformed row from reading "0 tracks went missing".
 		return "Some " + many
 	}
-	return fmt.Sprintf("%d %s", n, many)
+	return words.Count(n, one, many)
 }

internal/wanted/match.go

@@ -13,6 +13,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/musicbrainz"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/release"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/tags"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/words"
 )
 
 // Matching a library album to its MusicBrainz release group (#5569).
@@ -262,8 +263,8 @@ func (s *Service) matchAlbum(ctx context.Context, a dbq.ListAlbumsToMatchRow, tr
 	if considered == 0 {
 		return albumMatch{Detail: fmt.Sprintf("MusicBrainz has no album called %q by %s.", a.Title, a.ArtistName)}, nil
 	}
-	detail := fmt.Sprintf("MusicBrainz has %d %s called %q by %s, but none has its tracks: the closest, %q, agrees on %d of its %d",
+	detail := fmt.Sprintf("MusicBrainz has %s called %q by %s, but none has its tracks: the closest, %q, agrees on %d of its %d",
-		considered, plural(considered, "album", "albums"), a.Title, a.ArtistName, best.Title, max(bestN, 0), len(tracks))
+		words.Count(considered, "album", "albums"), a.Title, a.ArtistName, best.Title, max(bestN, 0), len(tracks))
 	switch {
 	case bestN < 0:
 		detail += " (MusicBrainz lists no edition of it)"
@@ -403,10 +404,3 @@ func abs(n int) int {
 	}
 	return n
 }
-
-func plural(n int, one, many string) string {
-	if n == 1 {
-		return one
-	}
-	return many
-}

internal/words/words.go

@@ -0,0 +1,15 @@
+// Package words says counts in English for what the server writes to people:
+// notifications, emails, the reasons a scan or a match gives.
+package words
+
+import "strconv"
+
+// Count says n with the noun that agrees with it: "1 track", "3 tracks". The
+// noun may carry its verb ("track went missing" / "tracks went missing").
+// The web app's plural() is the same thing on the other side (M505).
+func Count[N ~int | ~int32 | ~int64](n N, one, many string) string {
+	if n == 1 {
+		return "1 " + one
+	}
+	return strconv.FormatInt(int64(n), 10) + " " + many
+}

internal/words/words_test.go

@@ -0,0 +1,19 @@
+package words
+
+import "testing"
+
+func TestCount(t *testing.T) {
+	cases := []struct {
+		got, want string
+	}{
+		{Count(1, "track", "tracks"), "1 track"},
+		{Count(0, "track", "tracks"), "0 tracks"},
+		{Count(int64(3), "track went missing", "tracks went missing"), "3 tracks went missing"},
+		{Count(int32(-1), "copy", "copies"), "-1 copies"},
+	}
+	for _, c := range cases {
+		if c.got != c.want {
+			t.Errorf("got %q, want %q", c.got, c.want)
+		}
+	}
+}