/// <summary>
/// Returns all children of a location. Keeps the location in the list.
/// </summary>
/// <param name="location"></param>
/// <param name="locationIsAlreadyValidated"></param>
/// <returns></returns>
public IList <Location> GetChildren(Location location, bool locationIsAlreadyValidated = false)
{
var db = DbContextControl.GetLastOrNew();
Location current = location;
if (!locationIsAlreadyValidated)
{
//Check if the location exists in the database
current = GetLocation(db, location?.Name);
if (current == null)
{
throw new LocationNotFoundException();
}
}
//Find all locations whose parent is our location
IQueryable <Location> query
= db.Locations.Include("Parent").Where(l => l.Parent != null && l.Parent.Name == location.Name);
int results = query.Count();
IList <Location> validLocations = query.ToList();
IList <string> children = validLocations.ToNameList(); //Children to check, per iteration
//We need to loop this for the children of children, until we get no more new results
bool iterate = true;
while (iterate) //Do while there are still objects available
{
//Perform query to find all Locations whose parent is one of the previous children
query = db.Locations.Include("Parent").Where(l => l.Parent != null && children.Contains(l.Parent.Name));
//Count
results = query.Count();
if (results > 0) //Prepare next iteration
{
var newList = query.ToList(); //Turn the query into list of objects
validLocations = validLocations.Concat(newList).ToList(); //Add the newfound locations to the total list
children = newList.ToNameList(); //Specify the children to check for in the next iteration
}
else
{
iterate = false;
}
}
validLocations.Add(location);//Keep the current location in the list to simplify later use
return(validLocations);
}
/// <summary>
/// Checks if a location is within another location.
/// An example: Aalborg is within Nordjylland, is within Denmark
/// LocationIsWithin("Aalborg","Denmark") ---> true
/// </summary>
/// <param name="name">Location in question</param>
/// <param name="parent">The larger location</param>
/// <returns></returns>
public bool IsWithin(string name, string parent)
{
//Get a reference to a Database Context from Entity Framework
var db = DbContextControl.GetLastOrNew();
//Make sure that the name and parent arguments are existing locations
Location current = GetLocation(db, name);
Location parentLocation = GetLocation(db, parent);
if (current == null)
{
throw new LocationNotFoundException("Checking if non-existing location is within another.");
}
if (parentLocation == null)
{
throw new LocationNotFoundException("Checking if a location is within a non-existing one.");
}
//Now we try to traverse the Location tree, to find if two locations are connected
bool found = false; //Boolean flag to help us later
//While the current location is not null and we haven't found a match
while (current != null && !found)
{
//Check if the current location or its parent is the one parent we are looking for
if (current.Name == parent || current.Parent?.Name == parent)
{
found = true;//This makes the end result true, and also terminates the condition of the loop
}
//If there are no more parents, we are at the top of the tree and we are done searching
if (current.Parent == null)
{
//This terminates the condition of the loop
current = null;
}
else
{
//Otherwise, switch to the parent of the current location and repeat the loop
current = GetLocation(db, current.Parent.Name);
}
}
//If nothing is found, this remains false
return(found);
}
/// <summary>
/// Gets a page of ads that are within a location.
/// </summary>
/// <returns></returns>
public IList <Ad> GetAdsWithinLocation(int skip, int amount, string location)
{
if (amount > Throttle)
{
amount = Throttle;
}
IList <string> possibleLocationNames = GetPossibleLocationNames(location);
ServiceDbContext db = DbContextControl.GetLastOrNew();
IQueryable <Ad> query = db.Ads.Include("Location")
.Where(a => a.Location != null &&
possibleLocationNames.Contains(a.Location.Name));
var pagedQuery = query
.OrderByDescending(a => a.DatePosted)
.Skip(skip)
.Take(amount)
.Include(a => a.Author)
.ToList();
return(pagedQuery);
}
/// <summary>
/// Get a list of all locations that contain this location.
/// Starts with the current location.
/// Ordered from smallest to largest containing location.
/// </summary>
/// <param name="location">The location whose parents you are looking for.</param>
/// <returns></returns>
public IList <Location> GetParents(Location location, bool locationIsAlreadyValidated = false)
{
var db = DbContextControl.GetLastOrNew();
Location current = location;
if (!locationIsAlreadyValidated)
{
//Check if the location exists in the database
current = GetLocation(db, location?.Name);
if (current == null)
{
throw new LocationNotFoundException();
}
}
IList <Location> locations = new List <Location>();
//While we aren't at a null location
while (current != null)
{
//Add the current location to our list
locations.Add(current);
//Get the parent of the current (null if at the top of the tree)
if (current.Parent == null)
{
current = null; //If no more parents, terminate the loop
}
else
{
current = GetLocation(current.Parent.Name);
}
}
return(locations);
}
/// <summary>
/// Find a location from its name, since it's the only possible key.
/// This queries the DB.
/// </summary>
/// <param name="name"></param>
public Location GetLocation(string name)
{
var db = DbContextControl.GetLastOrNew();
return(db.Locations.Include("Parent").FirstOrDefault(l => l.Name.ToLower() == name.ToLower()));
}
