First Conditional in the Past

[witua]

I would like to know if the following sentence is correct:

"While waiting for John, he suddenly realized that she won't accept the gift if there are no $k$ consecutive candies of the same type."

In particular, is it OK to use the first conditional when describing something in the past? If not, what is the correct way?

Thanks.

[Rover_KE]

What are $k$ consecutive candies?

[witua]

Well, it's a "story" to a math problem statement, don't focus on that. Basically it means that some objects are placed in a row (in this case candies), and we have a condition that there should be at least k (a variable) consecutive objects of the same type.

[Matthew Wai]

https://www.usingenglish.com/forum/t...=1#post1165294
Having read the above, I think backshift can be used: use 'wouldn't' and 'were' instead of 'won't' and 'are' respectively.