def get_eta(self, order):
        eta_calc = zhibin_eta
        curr_location = self.get_location()

        # Is driver delivering (preassigned, or assigned order) ?
        if len(self.preassigned) or self.order:
            # Has order assigned ?
            if self.order:
                # Have enough Stock ?
                if self.have_enough_stock(order):
                    # ETA Distance assigned order +
                    # Buffer time +
                    # ETA Distance assigned order to New Order
                    return eta_calc(curr_location, self.order.location) + \
                        self.order.arrival_to_deliver_buffer + \
                        eta_calc(self.order.location, order.location)
                else:
                    # ETA Distance assigned order +
                    # Buffer time +
                    # ETA Distance to Hub +
                    # Buffer giving stock +
                    # ETA Distance to New Order
                    return eta_calc(curr_location, self.order.location) + \
                        self.order.arrival_to_deliver_buffer + \
                        eta_calc(self.order.location, HUB_LOCATION) + \
                        HUB_GIVING_STOCK_BUFFER + \
                        eta_calc(HUB_LOCATION, order.location)
            else:
                # No. (He has an order PREassigned)
                # ETA Distance to Hub +
                # Buffer giving stock +
                # ETA Distance to preassigned Order +
                # Buffer delivery +
                # ETA Distance to new order
                preassigned_order = self.preassigned[0]
                return eta_calc(curr_location, HUB_LOCATION) + \
                    HUB_GIVING_STOCK_BUFFER + \
                    eta_calc(HUB_LOCATION, preassigned_order.location) + \
                    preassigned_order.arrival_to_deliver_buffer + \
                    eta_calc(preassigned_order.location, order.location)
        else:
            if self.have_enough_stock(order):
                # ETA Distance to new order
                return eta_calc(curr_location, order.location)
            else:
                # ETA Distance to Hub +
                # Buffer giving stock +
                # ETA Distance to new order
                return eta_calc(curr_location, HUB_LOCATION) + \
                    HUB_GIVING_STOCK_BUFFER + \
                    eta_calc(HUB_LOCATION, order.location)