From reports, they were firing BM21s which appear to have a range of < 50km.
They were highly reckless firing into civilian areas around the border yesterday, if they somehow escalated to your sort of range and deeper into Thailand territory I think they could reasonably expect the Thai Air Force to further bomb the absolute living c--p out of them and start attacking military targets deeper in Cambodia.
Thailand has total military superiority, so it would be stupid to continue poking the bear.
Social media is full of nationalists of both sides with the cut, copy and paste statements. Quite frankly, I don't really care and we will never find out who fired the first shot, was does seem evident is that the Cambodians were indiscriminately firing missiles into Thai civilian areas.
I expect most neutral observers will judge that extremely negatively. The Cambodian leadership likely won't care a jot about global opinion, this whole exercise is more for domestic consumption and affirming their grip on power.
#Team Thailand