Foxes and Cows

Bulls and cows is a mind game (puzzle) where the player has to guess the secret code. After each guess the players gets two hints as to how close he is, the number of bulls is the amount of right symbols in the right place, the number of cows is the amount of right symbols, but in the wrong place. There's a twist however, in that you will be competing against another (AI controlled) player, taking turns to guess the code. Whoever guesses it first wins. Want a scary experience? Set the difficulty to maximum then keep track of your win to loss ratio...