public void RecalculateConnections(int touristAttractionId)
{
var targetAttraction = context.TouristAttractions
.Where(ta => ta.Id == touristAttractionId)
.Select(ta => new
{
AttractionId = ta.Id,
ta.Geoposition.Latitude,
ta.Geoposition.Longitude,
ta.CityId,
ta.Active
}).FirstOrDefault();
if (targetAttraction == null)
{
return;
}
//If it is active the matrix has to be recalculated
if (targetAttraction.Active)
{
//lookup for the attractions that dont have a connection attached to the target attraction
var attractionsForConnections = context.TouristAttractions
.Where(ta => ta.Id != targetAttraction.AttractionId && ta.CityId == targetAttraction.CityId && ta.Active && !ta.OriginPositionDistances.Any(opd => opd.DestinationId == targetAttraction.AttractionId))
.Select(ta => new
{
AttractionId = ta.Id,
ta.Geoposition.Latitude,
ta.Geoposition.Longitude,
}).ToList();
//Now there goes the distance calculation for each one
//Calculating distances from targetAttraction as origin and the rest as destinations
var targetAsDestinationConnections = attractionsForConnections
.Select(a => new TouristAttractionConnection
{
CityId = targetAttraction.CityId,
OriginId = a.AttractionId,
DestinationId = targetAttraction.AttractionId,
Distance = distanceCalculator.CalculateKmDistance(a.Latitude, a.Longitude, targetAttraction.Latitude, targetAttraction.Longitude)
});
var targetAsOriginConnections = targetAsDestinationConnections
.Select(c => new TouristAttractionConnection
{
CityId = targetAttraction.CityId,
OriginId = c.DestinationId,//In the last dataset query the destination was the target attraction
DestinationId = c.OriginId,
Distance = c.Distance
});
//Adding the connection same origin same destination
var sameOriginSameDestinationConnection = new TouristAttractionConnection
{
CityId = targetAttraction.CityId,
OriginId = targetAttraction.AttractionId,
DestinationId = targetAttraction.AttractionId,
Distance = 0.00
};
context.TouristAttractionConnections.Add(sameOriginSameDestinationConnection);
context.TouristAttractionConnections.AddRange(targetAsDestinationConnections);
context.TouristAttractionConnections.AddRange(targetAsOriginConnections);
}
else
{
//Here is the processing for the removal
var connectionsToRemove = context.TouristAttractionConnections
.Where(tac => tac.OriginId == targetAttraction.AttractionId || tac.DestinationId == targetAttraction.AttractionId)
.ToList();
context.TouristAttractionConnections.RemoveRange(connectionsToRemove);
}
context.SaveChanges();
}
