My crush is giving me mixed signals it’s really annoying

So I have a crush on this guy. I always stare him and this guy is not afraid to make eye contact whenever we walk past each other unlike my other 10 ex crushes. So it was all good , him and his friend sit right in front of me in class and he would purposely fight with his friend underneath the table and he would always turn around to see my reaction. So one day I smiled at him and he gave me dirty look, I was so shocked because I thought he could like me since I tried speaking to him about homework and stuff and he showed me but he never said anything he just showed me his work and idk he always wants to see my reaction.

Anyway after that rude incident, I completely avoided him because that was just so rude. He 283737% knew I had a crush on him so one time I walked past him and I completely avoided him looking somewhere else. And he looks at me whilst walking and turns around whilst walking with his friends at me. He makes eye contact with me before but never turns around like that. And then he held the door a few times but like there were people there like his friends so idk if that counts but he did hold the door for me later on. And he even cna rip to me and was like Do we put our books in here and I just said yes. He looked at me when I wasn’t looking at him and quickly turned away.

But I don’t understand why give me a dirty look when I smiled at you, like that was so rude