import { Db } from 'mongodb'
import { shards } from './mongoPool'

/**
 * Single-shard accessor for the costing group, kept so routes that haven't been
 * taught to fan out keep working unchanged.
 *
 * Safe while costing fits on one cluster - at ~0.3MB/day that is roughly 4.6
 * years on a 512MB M0. Routes still using this will silently read only shard 0
 * once costing spills, so they need converting to fanout() before that happens.
 */
export async function getDb(): Promise<Db> {
  const [first] = await shards('costing')
  return first
}