implemente attachemtn download route

app/bills/[id]/edit/page.tsx

@@ -1,38 +1,10 @@
 import { PlainLocation, PlainBill, MongoLocation } from '@/app/lib/db-types';
+import { fetchBillById } from '@/app/lib/fetchBillById';
 import clientPromise from '@/app/lib/mongodb';
 import { BillEditForm } from '@/app/ui/BillEditForm';
 import { ObjectId } from 'mongodb';
 import { notFound } from 'next/navigation';
 
-const fetchBillById = async (locationID:string, billID:string) => {
-    const client = await clientPromise;
-    const db = client.db("rezije");
-
-    // find a location with the given locationID
-    const billLocation = await db.collection<MongoLocation>("lokacije").findOne({ _id: locationID })
-
-    if(!billLocation) {
-        console.log(`Location ${locationID} not found`);
-        return(null);
-    }
-
-    // find a bill with the given billID
-    const mongoBill = billLocation?.bills.find(({ _id }) => _id.toString() === billID);
-
-    if(!mongoBill) {
-        console.log('Bill not found');
-        return(null);
-    }
-
-    const { _id, ...billBase  } = mongoBill;
-
-    return({
-        id: _id.toString(),
-        ...billBase
-    } as PlainBill);
-
-}
-
 export default async function Page({ params:{ id } }: { params: { id:string } }) {
 
     const [invoiceID, billID] = id.split('-');