/**
* Domain logic responsible for calculating distance and finding the closest few scooters to a given coordinate.
* First, we get all Scooters that's available in the database at the current moment.
* Next, we iterate through all the Scooters available and calculate their distance.
* If the distance is smaller than the specified distance (termed radius),
* the Scooter will be added to a List holding all nearest scooters.
* At the same time, their distance and UUID will be saved in a List of Tuples, which will be sorted.
* We will then find the UUID of scooters from the shortest distance first and add these Scooters to another
* list (called constrainNearestScooters). constrainNearestScooters will then hold a
* specific number of closest scooters to the given point and will be returned by this function.
*/
public IEnumerable <ScooterDomainModel> GetClosest(ScooterClosestDomainModel scooterClosestDomainModel)
{
Coordinates centreCoordinate = scooterClosestDomainModel.CentreCoordinate;
int nearestNumberOfScooters = scooterClosestDomainModel.NearestNumberOfScooters;
int radius = scooterClosestDomainModel.Radius;
IEnumerable <ScooterDomainModel> allScooters = _repository.GetAll().Result;
List <ScooterDomainModel> allNearestScooters = new List <ScooterDomainModel>();
List <ScooterDomainModel> constrainNearestScooters = new List <ScooterDomainModel>();
List <Tuple <double, Guid> > distanceOfAllNearestScooters = new List <Tuple <double, Guid> >();
foreach (ScooterDomainModel scooter in allScooters)
{
double distance = CoordinatesDistanceExtensions.GetDistance(
scooter.Longitude,
scooter.Latitude,
centreCoordinate.Longitude,
centreCoordinate.Latitude);
if (!(distance <= radius))
{
continue;
}
allNearestScooters.Add(scooter);
distanceOfAllNearestScooters.Add(new Tuple <double, Guid>(distance, scooter.Id));
}
distanceOfAllNearestScooters.Sort((x, y)
=> x.Item1.CompareTo(y.Item1));
while (nearestNumberOfScooters > 0 && distanceOfAllNearestScooters.Any())
{
var initialElement = distanceOfAllNearestScooters.First();
ScooterDomainModel desiredScooter = allNearestScooters.Find(model =>
model.Id.Equals(initialElement.Item2));
constrainNearestScooters.Add(desiredScooter);
nearestNumberOfScooters--;
distanceOfAllNearestScooters.Remove(initialElement);
}
return(constrainNearestScooters);
}
