public async Task <int?> UpgradeBuilding(long buildingId)
{
// Building not found = -1
// Building upgraded = 1
// Building not upgraded null
var building = kingdom.Buildings.FirstOrDefault(b => b.Id == buildingId);
if (building == null)
{
return(-1);
}
if (restrictionsService.CheckGoldForUpgradeBuilding(kingdom, building) && await restrictionsService.CheckLevelForUpgrade(kingdom, building))
{
await buildingService.ChangeBuildingLevel(building);
return(1);
}
return(null);
}