Block subscription if the license number is reached in a catalog item

[MalikB]

I need to add changes to an existing catalog item ->

block the form if the number of subscribers + active requests Teams Premium offer > 200
The value 200 must be configurable via a sysproperty


Set a sysproperty value > number of subscribers + requests in progress (at least 1) => Possibility to order
1 Set a sysproperty value < number of subscribers + current requests (at least 1) => Blocked order
2 The "Submit" button remains visible in all cases

Content of the form

Existing

1-> Requester R (user) O N always
2-> Beneficiary R (user) Mandatory Always visible

----------------------------------------

Modification to be made :

3-> Description of the need ->TB - Mandatory - Visible, Modification request by profession => Visibility conditions If nb licenses < 200

3.1-> The maximum number of Teams Premium licenses at XXXX has been reached. You can join the waiting list. L Change request by business => If nb licenses >= 200 (Budget approval fields)

L (label), TB (text box), TM (multi-line text), LD (drop-down list), LC (combo list), LM (multiple choice list), RB (radio button), CC (checkbox), S (Section), R (reference)

[ ] Nb licenses = Number of subscribers to the Teams Premium offer with Active = true + Requests with Active = true on this form [ ] The number 200 must be configurable via a sysproperty. [x] Block the form if the beneficiary is already subscribed to the Teams Premium offer (in the existing one) [ ] Block the form if nb licenses >= 200 with the error message (if not possible to put a link, delete the 2nd sentence): The number  maximum Teams Premium licenses at XXX has been reached. You can join the waiting list.

i don't know if this can help but there's is a general script includes I could find this script : 

setSubscription: function(user, service_offering) {

var checkDuplicateSubscription = new GlideRecord('service_subscribe_sys_user'); checkDuplicateSubscription.addQuery("sys_user", user);

checkDuplicateSubscription.addQuery("service_offering", service_offering); checkDuplicateSubscription.addQuery("u_active", true);

checkDuplicateSubscription.query();

if (!checkDuplicateSubscription.hasNext()) {

var createSubscription = new GlideRecord('service_subscribe_sys_user');

createSubscription.newRecord();

createSubscription.service_offering = service_offering; createSubscription.sys_user = user;

createSubscription.insert();

}

},