babaisyou.pl

at(baba_class, field(1, 1), 0).
at(is, field(1, 2), 0).
at(you_class, field(1, 3), 0).

at(flag_class, field(3, 1), 0).
at(is, field(3, 2), 0).
at(win_class, field(3, 3), 0).

at(baba, field(2, 2), 0).
at(flag, field(2, 3), 0).

at(Object, field(X1, Y1), Turn) :-
  succ(PrevTurn, Turn),
  you(Object, PrevTurn),
  move(right, PrevTurn),
  at(Object, field(X0, Y0), PrevTurn),
  X0 = X1,
  succ(Y0, Y1).

at(Object, Field, Turn) :-
  succ(PrevTurn, Turn),
  \+ you(Object, PrevTurn),
  at(Object, Field, PrevTurn).

h_pair(field(X1, Y1), field(X2, Y2)) :-
  X1 = X2,
  succ(Y1, Y2).
  
v_pair(field(X1, Y1), field(X2, Y2)) :-
  succ(X1, X2),
  Y1 = Y2.

prop(First, Second, Third, Turn) :-
  at(First, FirstField, Turn),
  at(Second, SecondField, Turn),
  at(Third, ThirdField, Turn),
  h_pair(FirstField, SecondField),
  h_pair(SecondField, ThirdField).

prop(First, Second, Third, Turn) :-
  at(First, FirstField, Turn),
  at(Second, SecondField, Turn),
  at(Third, ThirdField, Turn),
  v_pair(FirstField, SecondField),
  v_pair(SecondField, ThirdField).

class(baba, baba_class).
class(flag, flag_class).

you(Object, Turn) :-
  class(Object, Class),
  prop(Class, is, you_class, Turn).

win(Object, Turn) :-
  class(Object, Class),
  prop(Class, is, win_class, Turn).


move(right, 0).

game_won(Turn) :-
  you(Object1, Turn),
  win(Object2, Turn),
  at(Object1, Field, Turn),
  at(Object2, Field, Turn).