def get_cheapest_route(self):
# calculates the cost of each possible route and returns the cheapest route (and its cost)
if self.__error is not None: # if there are no valid routes for this itinerary
return None, 10 ** 10
lowest_cost = 10 ** 10 # method will return this number if itinerary cannot be completed
self.route_list = self.build_route_list()
self.cheapest_route = None
for route in self.route_list:
total_cost_of_stopovers = self.__stopover_cost * (len(route) - len(self.__airport_list))
try:
current_route = Route(route,
self.__aircraft_range,
self.__airport_atlas,
self.__currency_table,
self.__empty_tank,
total_cost_of_stopovers)
except ImpossibleRouteError:
continue # this route has a leg that cannot be completed
else:
current_route_cost = current_route.get_cost_of_route()
if current_route_cost < lowest_cost:
self.cheapest_route = current_route
lowest_cost = current_route_cost
if lowest_cost == 10 ** 10: # if itinerary cannot be completed
print("Aircraft has insufficient range to complete this itinerary.")
print("Consider using a larger aircraft or adding a fuel stop to the list of hubs.")
self.__error = "Aircraft has insufficient range to complete this itinerary." \
"\nConsider using a larger aircraft or adding a fuel stop to the list of hubs."
self.cheapest_route = None
else:
print()
print(self.cheapest_route)
self.cheapest_route.print_costs()
print()
self.lowest_cost = lowest_cost
return self.cheapest_route, lowest_cost
