update attribute insight when customfield Jira selected URGENT

[Solliffan]

Hi guys ! 

I'm Jira and I'm going to make a furniture sale, so I want the employees to be able to create tickets and choose the furniture they want to buy. So I created a custom Insight field that calls for objects in insight called "Desk", "Chair", "Lamp" and "Cabinet". These objects have a key "CI-11453" for the chair, "CI-11454" for the desk, "CI-11451" for the lamp and "CI-11452" for the box.

All these objects have an attribute "remaining stock", I would like that when a ticket is created with one of the furniture that its remaining stock decreases by 1 for each ticket. I want that when the stock reaches 0 for this object it is no longer possible to select it.

I already tried to add a groovy post insight function but nothing works, how to do?