My dad keeps eating my snacks and I fight with him abt it, AITAH?

I am 20 yo and ever since I was a kid, my dad keeps eating my snacks without my permission. Ever since I was a kid he would always just jokingly say that he would buy more later for me. He would never keep his word and to this day, he keeps eating the snacks I buy for me. I already try to buy a lot of sweets and snacks everytimr I go out (which is a lot), since my dad is very picky and is always in a bad mood when he is hungry. I never usually eat them so i think that's one more reason I get so frustrated when he just eats them.

Today, Idk why but I got especially angry. My relationship with him was never really good, but I understand and acknowledge the fact that he works hard to always provide me and my family, food and a place to live in. But I bought 2 snacks for me yesterday and I went to the kitchen and found out that my dad opened them both and left the leftovers at the table. I was so angry and when I asked if he ate them, he said yes. Then I told him that those snacks were mine, and he just simply said "i know", without diverting his eyes from his cellphone. I got angry saying that since the snacks were mine, he couldn't eat them and he said that he would buy me more later, an excuse he always gives and never follows through on.

I know that he is my dad and that maybe I am exaggerating and being petty. AITA?