feat: add play-dl search resolver

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/media/playDlResolver.ts

@@ -0,0 +1,59 @@
+import play from "play-dl";
+
+export interface PlayDlResult {
+  title: string;
+  url: string;
+}
+
+interface PlayDlSearchResult {
+  title?: string;
+  url?: string;
+}
+
+interface SpotifyTrackLike {
+  type?: string;
+  name?: string;
+  artists?: Array<{ name?: string }>;
+}
+
+type SearchFunction = (
+  query: string,
+  options: { limit: number },
+) => Promise<PlayDlSearchResult[]>;
+
+type SpotifyFunction = (url: string) => Promise<SpotifyTrackLike>;
+
+export interface PlayDlDependencies {
+  search?: SearchFunction;
+  spotify?: SpotifyFunction;
+}
+
+export function createPlayDlResolver(dependencies: PlayDlDependencies = {}) {
+  const search: SearchFunction = dependencies.search ?? play.search;
+  const spotify: SpotifyFunction = dependencies.spotify ?? (play.spotify as SpotifyFunction);
+
+  return {
+    async searchYouTube(query: string): Promise<PlayDlResult> {
+      const results = await search(query, { limit: 1 });
+      const first = results[0];
+      if (!first?.url) throw new Error(`No YouTube result found for ${query}`);
+      return {
+        title: first.title || query,
+        url: first.url,
+      };
+    },
+
+    async resolveSpotifyTrack(url: string): Promise<PlayDlResult> {
+      const track = await spotify(url);
+      if (track.type !== "track") {
+        throw new Error("Only Spotify track URLs are supported");
+      }
+      const artists = (track.artists || [])
+        .map((artist) => artist.name)
+        .filter(Boolean)
+        .join(" ");
+      const query = `${artists} ${track.name || ""} audio`.trim();
+      return this.searchYouTube(query);
+    },
+  };
+}

tests/media/playDlResolver.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, it, vi } from "vitest";
+import { createPlayDlResolver } from "../../src/media/playDlResolver";
+
+describe("createPlayDlResolver", () => {
+  it("returns the first YouTube search result", async () => {
+    const resolver = createPlayDlResolver({
+      search: vi.fn(async () => [
+        { title: "Song Result", url: "https://youtube.com/watch?v=abc" },
+      ]),
+      spotify: vi.fn(),
+    });
+
+    await expect(resolver.searchYouTube("artist song")).resolves.toEqual({
+      title: "Song Result",
+      url: "https://youtube.com/watch?v=abc",
+    });
+  });
+
+  it("turns Spotify track metadata into a YouTube search query", async () => {
+    const resolver = createPlayDlResolver({
+      search: vi.fn(async () => [
+        { title: "Artist - Track", url: "https://youtube.com/watch?v=track" },
+      ]),
+      spotify: vi.fn(async () => ({
+        type: "track",
+        name: "Track",
+        artists: [{ name: "Artist" }],
+      })),
+    });
+
+    await expect(
+      resolver.resolveSpotifyTrack("https://open.spotify.com/track/123"),
+    ).resolves.toEqual({
+      title: "Artist - Track",
+      url: "https://youtube.com/watch?v=track",
+    });
+  });
+
+  it("rejects Spotify playlists in this phase", async () => {
+    const resolver = createPlayDlResolver({
+      search: vi.fn(),
+      spotify: vi.fn(async () => ({ type: "playlist", name: "Playlist" })),
+    });
+
+    await expect(
+      resolver.resolveSpotifyTrack("https://open.spotify.com/playlist/123"),
+    ).rejects.toThrow("Only Spotify track URLs are supported");
+  });
+});