Tic tac toe game

I had some problems solving some of the game's features, however I managed to do everything by myself. I didn't manage to make the computer smart and I found the Minimax algorithm, which I adapted to work with my existing code. There are some bugs that I didn't know how to fix and the cleanliness of the code is probably not optimal because I added the Minimax at the end.

Your analyses, remarks or advice are welcome!