Did he ever like me? What happened?

I am a summer intern in an office. Last summer, another intern began at the same time as I did. We became friends with one of the full-time staff and frequently went to lunch with each other. There was a time when I thought perhaps he liked me. I’m useless at reading signs or flirtations so I’m not sure. He told me I was a “cute drunk”; we kept up an emailing correspondence and at one point he said “bite me” and when I wrote that I would he wrote back saying “mmmm” because he “likes the pain”. When he sent me a joke email recently I told him brats didn’t get to do fun things, brats get punished to which he responded with “Oh baby ;)”. Last summer when I said someone had apparently liked my ass at a restaurant he said “So do I”. And at one point last summer I invited him somewhere and must have made a quip about a ball (why, I don’t remember) which prompted him to ask if certain balls would also be invited. Aside from all of this, he used to be very sweet. He would invite me out to lunch, go to the bookstore; he told me to invite him whenever I head out to a certain bookstore; he would send me links to interesting photography techniques because he thought I had “photgraphy in you [me]“. He always texted me to make sure I got home safely after being out at night, he said we should hang out when we went back to school (we go to the same university in a different city). But when work ended last summer, we didn’t see each other. I invited him to a party, he couldn’t make it; we had plans to get Korean food, they never transpired. Eventually communication kind of dwindled and he only ever got in touch with me once a month, if that. I asked if he could help me fix my computer, he said he was able to do what needed to be done but never helped me. I asked if he wanted to grab coffee like we used to, and he just ignored the message. When we were about to start work again this summer he started texting me again, wanted to make sure I was going to be in orientation, and, at orientation, asked if I wanted to go with him and friends for drinks the upcoming Friday. The drinks thing didn’t happen because he forgot, so he invited me to see a movie; and we never made plans for it. He seemed jokingly upset when I left before him on our first day. The first day he kept getting in touch to ask “Sup?”. I’ve asked him if he was going to go to one of our socials, and he never responded; he doesn’t invite me to lunch anymore, he sends me links to funny things on the internet sometimes, but that’s it basically.
I have absolutely no idea what happened. It’s clear to me that he runs very hot and cold but I can’t figure out why.