It's a border clash not an invasion. Current situation is both side still exchanging fire with limited movement on the ground around dispute area to take advantage after cease fire declared on international stage.
Cambodia have inferior military overall, Thailand also have an advantage on RTAF. In case of both side put everything they have on each other. Thailand will have a better chance but that doesn't mean it will be a cake walk with minimal lost either.
Cambodia has used almost 90% of its force while Thailand has just used some 50% - 60% of its total power. In case of border clash with small weapon (rifle and RPG), Cambodia is no fear of Thailand because Cambodian soldiers are more battle-scar than Thai soldiers. But if that were a full-scale war, Cambodia has some disadvantage, first, less advanced equipment. Then, war means money burning. Cambodia cannot afford such high-cost war for an extending period.
PS. I notice Thai army has not deployed its beloved VT-4 yet.
Cambodia has asked for an unconditional ceasefire. Finally an intelligent move from them.
I believe Cambodian leaders know what they are doing, and these happened once a while in the past. First, small scale clash, then when clash escalates into heavy conflict, they will seek for external intervention while Thai side only wants to solve problems bilaterally.