Update stock when shop owner adds or removes items

[bjorn-out]

Currently, stock counts in the database are not updated when the shop owner adds or removes items. This can create a bit of a chicken/egg problem, where nobody visits shops that are shown as empty, which means there aren’t any transactions, which means the stock counts never get updated, etc.

ChestShop currently doesn’t have an event for stock updates. So I’m looking to add a new event for that to ChestShop (have asked the dev if it would be okay with them). Otherwise likely the only way to implement this is by listening to InventoryMoveItemEvent, which is computationally expensive.

[md5sha256]

Another possible option is to queue a partial resync of shops when a chunk is loaded. Now that we have a database, we can pull the relevant block positions for that chunk. Alternatively, we can also just queue resync of all known loaded shops every now and then.

[Technofied]

I have a strong suspicion this relates to me disabling inventory.ItemMoveEvent listener for ChestShop.

To verify, we need to check if adding stock to a shop updates the stock on the sign - I believe if the sign updates then it relates to what @bjorn-out was discussing over Discord, that maybe we need to explore an event for stock updates, for chestshop-database to work with?

Might be better addressed with our fork if Max doesn't wish to have such an event.

This is one line of thinking I had when I saw this issue, I could be off the mark though

[bjorn-out]

The signs do update on adding or removing of items.

ChestShop implements this here. They just listen to InventoryMoveItemEvent and call an internal function StockCounterModule.updateCounterOnItemMoveEvent() if the stock counter functionality is enabled. But ChestShop itself does not fire a separate event when that happens.

Max seems open to the idea of an event like this, but with some implementation details that make it a bit more work than I initially envisioned :-). See part of his response below.

On the other hand adding an event could enable the inbuilt stock counter to be extendable by making that cisten on the event rather than being hard coded in the Bukkit listeners so it might be worth exploring as cong as the performance impact is kept in mind (e.g. only firing the stock update event if listeners are registered).

But alternatively, yes, resyncing every now and then or basing it on chunk loading could also get us mostly there (although in that case syncing just prior to chunk unloading instead may result a more up-to-date database).

[Technofied]

just prior to chunk unloading instead may result a more up-to-date database
My only concern is chunks around spawn, they almost rarely if ever get unloaded unless on restart

I do agree with your assessment though overall