feat: resolve media music sources

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

tests/media/mediaResolver.test.ts

@@ -0,0 +1,42 @@
+import { mkdtempSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { describe, expect, it } from "vitest";
+import { AppError } from "../../src/errors";
+import { resolveMediaSource } from "../../src/media/mediaResolver";
+
+describe("resolveMediaSource", () => {
+  it("accepts http URLs", async () => {
+    await expect(resolveMediaSource("https://example.com/music.mp3")).resolves.toEqual({
+      source: "https://example.com/music.mp3",
+      title: "music.mp3",
+      kind: "url",
+    });
+  });
+
+  it("accepts existing local files", async () => {
+    const dir = mkdtempSync(path.join(tmpdir(), "media-resolver-"));
+    const file = path.join(dir, "song.ogg");
+    writeFileSync(file, "audio");
+
+    await expect(resolveMediaSource(file)).resolves.toEqual({
+      source: file,
+      title: "song.ogg",
+      kind: "local",
+    });
+  });
+
+  it("rejects empty sources", async () => {
+    await expect(resolveMediaSource("   ")).rejects.toMatchObject({
+      code: "MISSING_MEDIA_SOURCE",
+      statusCode: 400,
+    } satisfies Partial<AppError>);
+  });
+
+  it("rejects unsupported sources", async () => {
+    await expect(resolveMediaSource("not a url or file")).rejects.toMatchObject({
+      code: "UNSUPPORTED_MEDIA_SOURCE",
+      statusCode: 400,
+    } satisfies Partial<AppError>);
+  });
+});