feat(preview): MB getArtistName + browseReleaseGroupTracks

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/lib/musicbrainz-tracks.test.ts

@@ -0,0 +1,34 @@
+import { describe, it, expect, vi, afterEach } from "vitest";
+import { browseReleaseGroupTracks, getArtistName } from "./musicbrainz";
+
+afterEach(() => vi.restoreAllMocks());
+const ok = (obj: unknown) => new Response(JSON.stringify(obj), { status: 200 });
+
+describe("getArtistName", () => {
+  it("returns the MB artist name", async () => {
+    vi.spyOn(global, "fetch").mockResolvedValue(ok({ name: "Radiohead" }));
+    expect(await getArtistName("mbid")).toBe("Radiohead");
+  });
+});
+
+describe("browseReleaseGroupTracks", () => {
+  it("picks the Official release and flattens its tracks in order", async () => {
+    vi.spyOn(global, "fetch").mockResolvedValue(ok({
+      releases: [
+        { status: "Bootleg", date: "2001", media: [{ tracks: [{ position: 1, title: "Boot", length: 1000 }] }] },
+        { status: "Official", date: "2000", media: [
+          { tracks: [{ position: 1, title: "One", length: 200000 }, { position: 2, title: "Two", length: null }] },
+        ] },
+      ],
+    }));
+    expect(await browseReleaseGroupTracks("rg")).toEqual([
+      { position: 1, title: "One", lengthMs: 200000 },
+      { position: 2, title: "Two", lengthMs: null },
+    ]);
+  });
+
+  it("returns [] when there are no releases", async () => {
+    vi.spyOn(global, "fetch").mockResolvedValue(ok({ releases: [] }));
+    expect(await browseReleaseGroupTracks("rg")).toEqual([]);
+  });
+});

web/src/lib/musicbrainz.ts

@@ -63,3 +63,36 @@ export async function searchReleaseGroup(artist: string, album: string): Promise
   const credit = g["artist-credit"]?.[0]?.artist ?? {};
   return { ...toReleaseGroup(g), artistMbid: credit.id ?? "", artistName: credit.name ?? artist };
 }
+
+export type Track = { position: number; title: string; lengthMs: number | null };
+
+export async function getArtistName(mbid: string): Promise<string> {
+  const data = await mbGet(`/artist/${encodeURIComponent(mbid)}?fmt=json`);
+  return data.name ?? "";
+}
+
+export async function browseReleaseGroupTracks(rgMbid: string): Promise<Track[]> {
+  const data = await mbGet(
+    `/release?release-group=${encodeURIComponent(rgMbid)}&inc=recordings&fmt=json&limit=25`,
+  );
+  const releases: any[] = data.releases ?? [];
+  if (releases.length === 0) return [];
+  // Prefer an Official release, then the earliest date.
+  const pick = [...releases].sort((a, b) => {
+    const ao = a.status === "Official" ? 0 : 1;
+    const bo = b.status === "Official" ? 0 : 1;
+    if (ao !== bo) return ao - bo;
+    return (a.date ?? "9999").localeCompare(b.date ?? "9999");
+  })[0];
+  const tracks: Track[] = [];
+  for (const medium of pick.media ?? []) {
+    for (const t of medium.tracks ?? []) {
+      tracks.push({
+        position: Number(t.position ?? tracks.length + 1),
+        title: t.title ?? t.recording?.title ?? "",
+        lengthMs: t.length ?? t.recording?.length ?? null,
+      });
+    }
+  }
+  return tracks;
+}