Can you add support for the hammer to pull mats when upgrading the building?  Support for some upgrading plugins like building-grades and bgrade would also be excellent.

Hey,

I believe I tried to implement this feature before, however it only works if you already have the base materials for at least one upgrade in your inventory, as otherwise the client upgrade option is unavailable.
Further, there is no event sent to the server when the client tries to upgrade without having enough resources.