feat: restructure client-side code

src/server/tracks.js

@@ -0,0 +1,38 @@
+import fs from 'fs';
+import path from 'path';
+import { parseFile as mmParseFile } from 'music-metadata';
+import { DATA_DIR } from './config.js';
+import { loadYearsIndex } from './years.js';
+
+export async function listTracks() {
+  const years = loadYearsIndex();
+  const files = fs.readdirSync(DATA_DIR).filter((f) => /\.(mp3|wav|m4a|ogg)$/i.test(f));
+  const tracks = await Promise.all(
+    files.map(async (f) => {
+      const fp = path.join(DATA_DIR, f);
+      let year = null;
+      let title = path.parse(f).name;
+      let artist = '';
+      try {
+        const meta = await mmParseFile(fp, { duration: false });
+        title = meta.common.title || title;
+        artist = meta.common.artist || artist;
+        year = meta.common.year || null;
+      } catch {}
+      const y = years[f]?.year ?? year;
+      return { id: f, file: f, title, artist, year: y };
+    })
+  );
+  return tracks;
+}
+
+export function registerTracksApi(app) {
+  app.get('/api/tracks', async (req, res) => {
+    try {
+      const tracks = await listTracks();
+      res.json({ tracks });
+    } catch (e) {
+      res.status(500).json({ error: e.message });
+    }
+  });
+}