import { MongoClient } from 'mongodb'

let client = null
let db = null

export async function connectToDatabase() {
  if (db) {
    return db
  }

  const uri = process.env.MONGO_URI
  if (!uri) {
    throw new Error('MONGO_URI environment variable is not set')
  }

  try {
    client = new MongoClient(uri)
    await client.connect()
    db = client.db('faber-finances')
    console.log('Connected to MongoDB')
    return db
  } catch (error) {
    console.error('Failed to connect to MongoDB:', error)
    throw error
  }
}

export async function getCollection(name) {
  const database = await connectToDatabase()
  return database.collection(name)
}

// Close connection (useful for cleanup)
export async function closeDatabaseConnection() {
  if (client) {
    await client.close()
    client = null
    db = null
    console.log('Disconnected from MongoDB')
  }
}