private async Task <RoutePoint> FindRoute(RoutePoint currentPoint, string destinationAirport)
{
if (_found)
{
return(null);
}
_cancellationToken.ThrowIfCancellationRequested();
//lets skip it if it has been processed already
if (_processedAirports.GetOrAdd(currentPoint.Airport, currentPoint) != currentPoint)
{
return(null);
}
var accessibleAirports = await _routeProvider.Get(currentPoint.Airport, _cancellationToken);
// filter out already processed points
var notProcessedAirports = accessibleAirports.Where(aa => !_processedAirports.ContainsKey(aa.DestAirport));
ConcurrentBag <FlightsServiceClient.Models.Route> activeAirports = new ConcurrentBag <FlightsServiceClient.Models.Route>();
var activeAirportTasks = notProcessedAirports.Select(async npa => {
if (await IsAirlineActive(npa.Airline))
{
activeAirports.Add(npa);
}
});
await Task.WhenAll(activeAirportTasks);
_cancellationToken.ThrowIfCancellationRequested();
RoutePoint routePoint = null;
var route = activeAirports.Where(npa => npa.DestAirport == destinationAirport).FirstOrDefault();
if (route != null)
{
routePoint = new RoutePoint()
{
Airport = route.DestAirport, Route = route, Previous = currentPoint
};
_found = true;
}
else
{
var tasks = activeAirports.Select(async npa => {
var activeAirportRoutePoint = new RoutePoint()
{
Airport = npa.DestAirport, Route = npa, Previous = currentPoint
};
var foundRoute = await FindRoute(activeAirportRoutePoint, destinationAirport);
if (foundRoute != null && routePoint == null)
{
routePoint = foundRoute;
}
});
await Task.WhenAll(tasks);
}
return(routePoint);
}
public async Task <Journey> Build()
{
_cancellationToken.ThrowIfCancellationRequested();
if (string.Equals(_sourceAirportAlias, _destinationAirportAlias, StringComparison.InvariantCultureIgnoreCase))
{
return new Journey {
Routes = new Route[] { }
}
}
;
var sourceAirport = await _airportProvider.Get(_sourceAirportAlias, _cancellationToken);
if (sourceAirport == null)
{
throw new AirportNotFoundException($"Airport {_sourceAirportAlias} not found.");
}
_cancellationToken.ThrowIfCancellationRequested();
var destinationAirport = await _airportProvider.Get(_destinationAirportAlias, _cancellationToken);
if (destinationAirport == null)
{
throw new AirportNotFoundException($"Airport {_destinationAirportAlias} not found.");
}
List <Route> routes = new List <Route>();
var currentPoint = new RoutePoint {
Airport = sourceAirport.Alias
};
var routePoint = await FindRoute(currentPoint, destinationAirport.Alias);
if (routePoint == null)
{
return(null);
}
return(new Journey {
Routes = ConvertRoutePointToRouts(routePoint)
});
}
private Route[] ConvertRoutePointToRouts(RoutePoint routePoint)
{
int numberOfPoints = 0;
RoutePoint current = routePoint;
while (current != null && current.Route != null)
{
numberOfPoints++;
current = current.Previous;
}
current = routePoint;
Route[] routes = new Route[numberOfPoints];
int i = numberOfPoints - 1;
while (current != null && current.Route != null)
{
routes[i] = current.Route;
current = current.Previous;
i--;
}
return(routes);
}