import { Filter, MongoClient, WithId } from 'mongodb';

// Define a simple user document type
interface User {
  name: string;
  email: string;
  age: number;
}

async function main() {
  const client = new MongoClient('mongodb://localhost:27017');
  const db = client.db('test');
  const collection = db.collection<User>('users');

  // ✅ This correctly compiles - 'name' exists in the User schema
  await collection.findOne({ name: 'John' });

  // ✅ This correctly compiles - '_id' is automatically added by WithId<T>
  await collection.findOne({ _id: new ObjectId('507f1f77bcf86cd799439011') });

  // ❌ PROBLEM: This SHOULD be a TypeScript error, but it compiles successfully!
  // 'id' is NOT a field in the User interface, yet TypeScript allows it
  await collection.findOne({ id: '507f1f77bcf86cd799439011' });

  // ❌ PROBLEM: Same issue - 'userId' doesn't exist but no error
  await collection.findOne({ userId: 'some-id' });

  // ❌ PROBLEM: Completely made up field - still no error
  await collection.findOne({ nonExistentField: 'value' });

  // The reason this happens is because MongoDB's Filter type includes:
  // [key: string]: any
  // which allows any string key to be used as a filter field
}