class bank_machine {
  messaging::receiver incoming;
  unsigned balance;

public:
  bank_machine() : balance(199) {}
  void done() { get_sender().send(messaging::close_queue()); }
  void run()
  {
    try {
      for (;;) {
        incoming.wait()
            .handle<verify_pin>([&](verify_pin const& msg) {
              if (msg.pin == "1937") {
                msg.atm_queue.send(pin_verified());
              }
              else {
                msg.atm_queue.send(pin_incorrect());
              }
            })
            .handle<withdraw>([&](withdraw const& msg) {
              if (balance >= msg.amount) {
                msg.atm_queue.send(withdraw_ok());
                balance -= msg.amount;
              }
              else {
                msg.atm_queue.send(withdraw_denied());
              }
            })
            .handle<get_balance>([&](get_balance const& msg) {
              msg.atm_queue.send(::balance(balance));
            })
            .handle<withdrawal_processed>(
                [&](withdrawal_processed const& msg) {})
            .handle<cancel_withdrawal>([&](cancel_withdrawal const& msg) {});
      }
    }
    catch (messaging::close_queue const&) {
    }
  }
  messaging::sender get_sender() { return incoming; }
};