public async Task <decimal> CalculateFinalPriceAsync()
{
if (_carType == null || _settings == null)
{
using (var db = new CarRentalDatabase())
{
_carType = _carType ?? await db.CarTypes.FirstOrDefaultAsync(x => x.Id == CarTypeId);
_settings = _settings ?? await db.Settings.FirstOrDefaultAsync();
}
}
var days = (int)Math.Ceiling(DateTo.Subtract(DateFrom).TotalDays) + 1;
var mileage = FinalMileage - InitialMileage;
return(_carType.DayMultiplier * days * _settings.DayPrice
+ _carType.KilometerMultiplier * mileage * _settings.KilometerPrice);
}