const key = `${channel}-${version}.zip`;
await c.env.BUNDLES.put(key, await file.arrayBuffer());

const manifest = {
  version, key, checksum,
  url: `${origin}/api/ota/bundle/${key}`,
  updated: new Date().toISOString(),
};
await c.env.OTA_MANIFEST.put(`manifest:${channel}`, JSON.stringify(manifest));

// record in D1 for history / rollback
await c.env.RouteDB.prepare(
  'INSERT INTO history (channel, version, filename, uploaded_at, checksum) VALUES (?, ?, ?, datetime("now"), ?)'
).bind(channel, version, key, checksum).run();

const { version_build, channel = 'stable' } = await req.json();

const manifest = JSON.parse(
  await c.env.OTA_MANIFEST.get(`manifest:${channel}`)
);

if (manifest.version !== version_build) {
  return c.json({
    version: manifest.version,
    url: manifest.url,
    checksum: manifest.checksum,
  });
}

return c.json({});  // already up to date

// after deleting from BUNDLES + D1...
const { results } = await c.env.RouteDB.prepare(
  'SELECT version, filename FROM history WHERE channel = ? ORDER BY uploaded_at DESC LIMIT 1'
).bind(channel).all();

if (results.length > 0) {
  // promote the previous bundle to active
  await c.env.OTA_MANIFEST.put(`manifest:${channel}`, JSON.stringify(newManifest));
} else {
  // no more bundles — clear the manifest
  await c.env.OTA_MANIFEST.delete(`manifest:${channel}`);
}