public LocPocQuery(ILocationsRepositoryAsync repository)
{
Field <ListGraphType <LocationType> >(
"locations",
resolve: context => repository.GetAllAsync()
);
}
public async Task <ActionResult <IEnumerable <DTOs.Location> > > Get()
{
var locations = await _locationsRepository.GetAllAsync();
var locationDTOs = locations.Select(loc => loc.ToLocationDto());
return(Ok(locationDTOs));
}
public async Task <IEnumerable <LocationWithDistanceFromStartingPoint> > GetNearestLocations(StartingLocation startingLocation, int maxDistance, int maxResults)
{
EnsureArg.IsNotNull(startingLocation, nameof(startingLocation));
EnsureArg.IsGte(maxDistance, 0, nameof(maxDistance));
EnsureArg.IsGt(maxResults, 0, nameof(maxResults));
// In the case of an actual database with lots of records, we can use caching to save time when
// fetching al the records.
var allLocations = await _locationsRepository.GetAllAsync();
var startLoc = new Location(startingLocation.Latitude, startingLocation.Longitude);
// Time complexity depends on the size of M. Worst case if M is big then TC=O(M log M), else Omega(N)
var res = allLocations
.Select(l => new LocationWithDistanceFromStartingPoint(l, l.CalculateDistance(startLoc))) // Select: O(N)
.Where(l => l.DistanceFromStartingPoint <= maxDistance) // Where: O(N)
.OrderBy(l => l.DistanceFromStartingPoint) //O(M log M)
.Take(maxResults); // Take: O(M)
return(res);
}
