Hook for cart rule

[cedricfontaine]

Is there a way to add some condition to cart rule without modifying the core ? I want to block some rules on some days (valentine day for example).

I know how to do it by modifying the core, but it's strange that there is no hook when custom use a coupon code for example.

[bellini13]

What if you did something with a Product/Customer condition.

 

On a given day, change the cart rule so it only applies to a disabled product, or to a "fake" customer or group.  You should be able to automate that from a module or cron?

 

I'm trying to think outside the box and work around there being no hook