:- dynamic(move/2).
:- dynamic(hits/2).
:- dynamic(misses/2).
:- dynamic(sunks/2).
:- dynamic(position/2).

move(1,1).
move(1,2).
move(1,3).
move(1,4).
move(1,5).
move(2,1).
move(2,2).
move(2,3).
move(2,4).
move(2,5).
move(3,1).
move(3,2).
move(3,3).
move(3,4).
move(3,5).
move(4,1).
move(4,2).
move(4,3).
move(4,4).
move(4,5).
move(5,1).
move(5,2).
move(5,3).
move(5,4).
move(5,5).

target(X,Y):-
    move(X,Y),
  retract(move(X,Y)),
  assert(position(X,Y)).

hit:-
  position(X,Y),
  assert(hits(X,Y)),
  retract(position(X,Y)).

sunk:-
  position(X,Y),
  assert(hits(X,Y)),
  hits_to_sunks,
  retract(position(X,Y)).

miss:-
  position(X,Y),
  assert(misses(X,Y)),
  retract(position(X,Y)).


hits_to_sunks:-
  hits(X,Y),
  assert(sunks(X,Y)),
  remove_perimeter(X,Y).

remove_perimeter(X,Y):-
 Right is Y + 1,
 Top is X - 1,
 Bottom is X + 1,
 %RemoveBottom
 (X < 5, retract(move(Bottom,Y)));
 %RemoveTop
 (X > 1 , retract(move(Top,Y)));
 %RemoveRight
 (Y < 5, retract(move(X,Right)));
 %RemoveTopRight
 (Y < 5, X >1 , retract(move(Top,Right)));
  %RemoveBottomRight
 (Y < 5, X < 5 , retract(move(Bottom,Right))).

remove_move(X,Y):-
  retract(move(X,Y)).