feat: automatic ads data loading and attributed sales line in chart

api/fetch-ads.ts

@@ -0,0 +1,32 @@
+import type { VercelRequest, VercelResponse } from '@vercel/node';
+
+const ADS_DROPBOX_URL = "https://www.dropbox.com/scl/fi/wng8tep7awhvzd65amwad/Ads-Weekly.xlsx?rlkey=kcmoq8dxgibsb2eb8zz47xvyo&st=z02m4w3g&dl=1";
+
+export default async function handler(req: VercelRequest, res: VercelResponse) {
+    // CORS headers
+    res.setHeader('Access-Control-Allow-Origin', '*');
+    res.setHeader('Access-Control-Allow-Methods', 'GET, OPTIONS');
+    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
+
+    if (req.method === 'OPTIONS') {
+        return res.status(200).end();
+    }
+
+    try {
+        console.log('[fetch-ads] Fetching Ads from Dropbox...');
+        const response = await fetch(ADS_DROPBOX_URL);
+
+        if (!response.ok) {
+            throw new Error(`Dropbox responded with ${response.status}`);
+        }
+
+        const buffer = await response.arrayBuffer();
+        console.log('[fetch-ads] Successfully fetched Ads Excel, size:', buffer.byteLength);
+
+        res.setHeader('Content-Type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
+        res.status(200).send(Buffer.from(buffer));
+    } catch (error: any) {
+        console.error('[fetch-ads] Error:', error);
+        res.status(500).json({ error: error.message });
+    }
+}