Database transactions for data consistency

                  class TransferFundsService
  def initialize(from_account:, to_account:, amount:)
    @from_account = from_account
    @to_account = to_account
    @amount = amount
  end

  def call
    ActiveRecord::Base.transaction do
      # Lock rows to prevent concurrent modifications
      from = Account.lock.find(@from_account.id)
      to = Account.lock.find(@to_account.id)

      raise InsufficientFundsError if from.balance < @amount

      from.update!(balance: from.balance - @amount)
      to.update!(balance: to.balance + @amount)

      Transaction.create!(
        from_account: from,
        to_account: to,
        amount: @amount,
        status: 'completed'
      )
    end

    Result.success
  rescue InsufficientFundsError => e
    Result.failure(error: 'INSUFFICIENT_FUNDS')
  rescue StandardError => e
    Rails.logger.error("TransferFundsService failed: #{e.message}")
    Result.failure(error: 'TRANSFER_FAILED')
  end
end