public async Task GetPriceEstimation(PriceEstimationInputModel inputModel)
{
const double AdditionalAreaFactor = 0.3; //Additional area is worth 30% as much as the main area
// Get Sold objects in area
var previouslySoldObjectsInArea = await _booliPriceEstimatorRepository.GetSoldObjectsInArea(inputModel.AreaName);
// Filter
previouslySoldObjectsInArea = previouslySoldObjectsInArea.Where(l => l.LivingArea > 0 && l.SoldPrice > 0).ToList();
var estimationModels = previouslySoldObjectsInArea.Select(_ => new PriceEstimationModel(_)).ToList();
//var adjustedSquareMeterPrice = GetSquareMeterPriceBasedOnRent(estimationModels, inputModel);
var adjustedSquareMeterPrice = GetSquareMeterPriceBasedOnLocation(estimationModels, inputModel);
// Is it close to water?
// Is it a new building?
// Is it high up?
// What direction is the price heading/ trending? Can we get a 1st or 2nd degree coefficient? By only focusing on last 2Q we can ignore this....
// How many objects have been sold?
var priceEstimate = adjustedSquareMeterPrice * inputModel.Size;
if (inputModel.AdditionalArea != 0)
{
priceEstimate += (int)Math.Round(inputModel.AdditionalArea * AdditionalAreaFactor);
}
Console.WriteLine($"A apartment in {inputModel.AreaName} that is {inputModel.Size} square meters large and with a rent of {inputModel.Rent} SEK/ month is estimated to: ");
Console.WriteLine(string.Format("{0:#,0}", priceEstimate) + " SEK");
Console.ReadLine();
}
static void Main(string[] args)
{
// configure services
var services = new ServiceCollection()
.AddTransient <IBooliPriceEstimatorRepository, BooliPriceEstimatorRepository>()
.AddTransient <IBooliApiHandler, BooliApiHandler>()
.AddTransient <IBooliPriceEstimator, BooliPriceEstimator>()
.AddDbContext <BooliPriceEstimatorContext>(_ => _.UseSqlServer(@"Server=localhost;Database=Booli.Kodprov;Trusted_Connection=True;ConnectRetryCount=0"));
// create a service provider from the service collection
var serviceProvider = services.BuildServiceProvider();
// resolve the dependency graph
//var booliApiHandler = serviceProvider.GetService<IBooliApiHandler>();
//booliApiHandler.SyncSoldObjectsItteratively().Wait();
var booliPriceEstimator = serviceProvider.GetService <IBooliPriceEstimator>();
//booliApiHandler.SyncSoldObjectsItteratively().Wait();
var estimationInputModel = new PriceEstimationInputModel(74, "Årsta", 5000, StreetNameExamples.Siljansvagen72);
booliPriceEstimator.GetPriceEstimation(estimationInputModel).Wait();
}
private int GetSquareMeterPriceBasedOnLocation(List <PriceEstimationModel> estimationModels, PriceEstimationInputModel inputModel)
{
const int ThresholdNrOfObjects = 10;
const int SearchDistanceKm = 1;
// Maybe do these two itteratively until we find a good number of candidates?
//1.
var now = DateTime.Now;
var recentlySold = estimationModels.Where(em => (now - em.SoldDate.SoldDateTime).Days < 365).ToList();
if (recentlySold.Count < ThresholdNrOfObjects)
{
throw new Exception($"{recentlySold.Count}, too few sold objects found in the area dating a year back!");
}
//2.
var recentlySoldNearObjectOfInterest = recentlySold.Where(rs => (double)Calculations.PositionsToMetersDistance(rs.Position, inputModel.Position) / 1000.0 < SearchDistanceKm).ToList();
if (recentlySoldNearObjectOfInterest.Count < ThresholdNrOfObjects)
{
throw new Exception($"{recentlySoldNearObjectOfInterest.Count}, too few sold objects in within a {SearchDistanceKm} km radius found!");
}
SetRentRange(recentlySoldNearObjectOfInterest, inputModel);
var rentFactor = GetRentFactor(inputModel.RentRange);
var medianSquareMeterPrice = GetMedianSquareMeterPrice(recentlySoldNearObjectOfInterest);
return((int)(medianSquareMeterPrice * rentFactor));
//return (int)(medianSquareMeterPrice ); //I found it more accurate if I removed rent factor
}
private PriceEstimationModel GetSoldObjectWithSimilarRent(List <PriceEstimationModel> last2QSoldObjects, PriceEstimationInputModel inputModel)
{
var soldModelsOrderedByRent = last2QSoldObjects.OrderBy(_ => _.Rent).ToList();
var previousSoldModel = soldModelsOrderedByRent[0];
for (int i = 1; i < soldModelsOrderedByRent.Count; i++)
{
var currentSoldModel = soldModelsOrderedByRent[i];
if (currentSoldModel.Rent > inputModel.Rent)
{
var nearestSoldModelByRent = GetNearestSoldModel(previousSoldModel, currentSoldModel, inputModel.Rent);
return(nearestSoldModelByRent);
}
}
return(soldModelsOrderedByRent.Last());
}
//private int GetRecentlySoldObjects(List<PriceEstimationModel> estimationModels)
//{
// var now = DateTime.Now;
// var recentlySold = estimationModels.Where(em => (now - em.SoldDate.SoldDateTime).Days < 365).ToList();
// return recentlySold;
//}
private int GetSquareMeterPriceBasedOnRent(List <PriceEstimationModel> estimationModels, PriceEstimationInputModel inputModel)
{
const int thresholdNrOfObjects = 10;
//Get mean for the last 2 quarters.
var last2QSoldObjects = GetPreviousTwoQuartersSoldData(estimationModels);
if (last2QSoldObjects.Count < thresholdNrOfObjects)
{
//do something cool
}
//Calculations.CoordinatesToMeters
// Is the rent high for the area?
//var lowestNonZeroRentModel = last2QSoldObjects.Where(_ => _.Rent != 0).OrderBy(_ => _.Rent).First();
//var highestNonZeroRentModel = last2QSoldObjects.Where(_ => _.Rent != 0).OrderByDescending(_ => _.Rent).First();
// Where on the scale is the subject?
var mostSimilarRentSubject = GetSoldObjectWithSimilarRent(last2QSoldObjects, inputModel);
var baseRent = mostSimilarRentSubject.Rent;
return((int)baseRent);
}
private void SetRentRange(List <PriceEstimationModel> recentlySoldNearObjectOfInterest, PriceEstimationInputModel inputModel)
{
const double RentPercentageDiffThreshold = 0.2;// +- 20% threshold of median rent
var medianRentPrice = GetMedianRentPrice(recentlySoldNearObjectOfInterest);
//var maxVariation = GetLowestRent
// 2. Figure out if inputModel is +- 20% of median
var rentDiff = (double)inputModel.Rent / (double)medianRentPrice;
// rent diff is less than 80% of median
if (rentDiff < (1 - RentPercentageDiffThreshold)) //20% less than median
{
inputModel.RentRange = RentRange.Below;
}
// rent diff is more than 120% of median
else if (rentDiff > (1 + RentPercentageDiffThreshold)) //20% less than median
{
inputModel.RentRange = RentRange.Above;
}
else
{
inputModel.RentRange = RentRange.Average;
}
}