public TaxiInstructions GetTaxiInstructions(Point callerPosition)
{
TaxiPoint source;
try
{
source = _airfield.TaxiPoints.OrderBy(taxiPoint => taxiPoint.DistanceTo(callerPosition.Coordinate))
.First();
}
catch (NullReferenceException)
{
throw new TaxiPathNotFoundException($"Taxi path not available because no TaxiPoints found");
}
Logger.Debug($"Player is at {callerPosition.Coordinate}, nearest Taxi point is {source}");
var runways = ActiveRunwayDecider.GetActiveRunways(_airfield);
return(runways.Count == 1 ? GetTaxiInstructionsWhenSingleRunway(source, runways.First()) : GetTaxiInstructionsWhenMultipleRunways(source, runways));
}
private List <List <TaggedEdge <NavigationPoint, string> > > GetPathsToActiveRunways()
{
// First we get a list of active runway(s)
var activeRunways = ActiveRunwayDecider.GetActiveRunways(_airfield);
// Then we get a list of all the entry Waypoints
var entryPoints = _airfield.WayPoints.Where(x => x.Name.ToLower().Contains("entry"));
var paths = new List <KeyValuePair <double, List <TaggedEdge <NavigationPoint, string> > > >();
// Get all the paths from all the entry waypoints to the active runway(s)
foreach (var entryPoint in entryPoints)
{
var tryGetPaths =
_airfield.NavigationGraph.ShortestPathsDijkstra(_airfield.NavigationCostFunction, entryPoint);
foreach (var runway in activeRunways)
{
if (!tryGetPaths(runway, out var path))
{
continue;
}
var taggedEdges = path.ToList();
var pathCost = PathCost(taggedEdges);
var pathWithCost = new KeyValuePair <double, List <TaggedEdge <NavigationPoint, string> > >(pathCost, taggedEdges);
paths.Add(pathWithCost);
}
}
// Sort so that we get the cheapest ones first
var cheapestPathsByCost = paths.OrderBy(pair => pair.Key).ToList();
// This is the cheapest one, so we want this one and any that have the same cost
// since there could be multiple entry points for a given active runway(s).
var cheapestCost = cheapestPathsByCost.First().Key;
cheapestPathsByCost.RemoveAll(pair => pair.Key > cheapestCost);
// And finally return the paths so the caller can find the one with the closest
// start point to the player, which will be the actual approach path.
return(cheapestPathsByCost.Select(pathPair => pathPair.Value).ToList());
}