import { getCollection } from '../../utils/db.js'

export default defineEventHandler(async (event) => {
  try {
    const transactions = await readBody(event)
    const collection = await getCollection('transactions')
    
    // Clear existing transactions and upsert new ones
    await collection.deleteMany({})
    
    if (transactions.length > 0) {
      // Convert transactions for MongoDB and use bulk upsert operations
      const bulkOps = transactions.map(transaction => ({
        replaceOne: {
          filter: { _id: transaction.id },
          replacement: {
            ...transaction,
            _id: transaction.id,
            id: undefined,
            date: new Date(transaction.date),
            endDate: transaction.endDate ? new Date(transaction.endDate) : null,
            createdAt: new Date(),
            updatedAt: new Date()
          },
          upsert: true
        }
      }))
      
      const result = await collection.bulkWrite(bulkOps)
      
      return {
        success: true,
        insertedCount: result.upsertedCount,
        modifiedCount: result.modifiedCount
      }
    }
    
    return {
      success: true,
      insertedCount: 0
    }
  } catch (error) {
    console.error('Error bulk updating transactions:', error)
    throw createError({
      statusCode: 500,
      statusMessage: 'Failed to bulk update transactions'
    })
  }
})