"""Bounded oldest-message reading through the app's JavaScript database API."""

PROBE = r'''(async () => {
 if(location.origin!=='https://web.whatsapp.com')throw Error('Unexpected origin');
 const table=require('WAWebSchemaMessage').getMessageTable();
 const serializer=require('WAWebDBMessageSerialization');
 if(!(await indexedDB.databases()).some(d=>d.name==='model-storage'))throw Error('Database absent');
 const db=await new Promise((resolve,reject)=>{
  const r=indexedDB.open('model-storage');
  r.onupgradeneeded=()=>{r.transaction.abort();reject(Error('Refusing database upgrade'));};
  r.onsuccess=()=>resolve(r.result);r.onerror=()=>reject(Error('Database open failed'));
 });
 let scanned=0;
 try {
  const oldest=await new Promise((resolve,reject)=>{
   const tx=db.transaction('message','readonly'),store=tx.objectStore('message'),rows=[];
   const r=store.openCursor();
   r.onerror=()=>reject(Error('Cursor failed'));tx.onabort=()=>reject(Error('Transaction aborted'));
   r.onsuccess=()=>{
    const c=r.result;if(!c){resolve(rows);return;}
    if(++scanned>100000) {reject(Error('History scan exceeds 100000 rows'));return;}
    const t=c.value.t;
    if(typeof t==='number'&&Number.isFinite(t)&&t>0){
     rows.push({key:c.primaryKey,t});rows.sort((a,b)=>a.t-b.t);if(rows.length>5)rows.pop();
    }
    c.continue();
   };
  });
  const messages=[];
  for(const candidate of oldest){
   const row=await table.get(candidate.key);
   if(!row)throw Error('Selected row disappeared');
   if(row.msgRowOpaqueData&&typeof row.msgRowOpaqueData==='object'&&'_data' in row.msgRowOpaqueData)
    throw Error('Payload remains encrypted');
   const m=serializer.messageFromDbRow(row);
   messages.push({id:candidate.key,timestamp:m.t,type:m.type,
    body:typeof m.body==='string'?m.body:null,caption:typeof m.caption==='string'?m.caption:null,
    selected_timestamp:candidate.t});
  }
  return {scanned,sample_limit:5,source:'WAWebSchemaMessage.getMessageTable().get + WAWebDBMessageSerialization.messageFromDbRow',
   cdp:false,messages};
 }finally{db.close();}
})()'''