isFizz(Num) :- 0 is Num mod 3.
isBuzz(Num) :- 0 is Num mod 5.
isFizzbuzz(Num) :- isFizz(Num), isBuzz(Num).

fizzbuzz(Num, Res) :- 
  isFizzbuzz(Num) -> Res = 'fizzbuzz';
    isFizz(Num) -> Res = 'fizz';
    isBuzz(Num) -> Res = 'buzz';
    Res = Num.

fizzbuzzes(TopNum, TopNum, List) :-
  List = [],!.
fizzbuzzes(TopNum, CurrentNum, [Head | Tail]) :- 
  CurrentNum > TopNum -> throw('the CurrentNum is greater than TopNum'); 
  TopNum < 1 -> throw('the TopNum is less than 1'); 
  (NextNum is CurrentNum + 1,
  fizzbuzz(CurrentNum, Head),
  fizzbuzzes(TopNum, NextNum, Tail)).

fizzbuzzes(TopNum, List) :- 
  OneHigher is TopNum + 1,
  fizzbuzzes(OneHigher, 1, List).

printFizzbuzzes(TopNum) :-
  fizzbuzzes(TopNum, FizzbuzzList),
  forall(member(X, FizzbuzzList), (print(X), nl)). 

main :- 
  printFizzbuzzes(20), 
  halt.


% Test Cases

:- begin_tests(fizzbuzz).

test(isFizz_isnot) :-
  not(isFizz(5)).

test(fizzbuzz_fizz) :-
  fizzbuzz(3, 'fizz').

test(fizzbuzzes_empty) :-
  fizzbuzzes(0, []).

test(fizzbuzzes_5) :-
  fizzbuzzes(5, [1, 2, fizz, 4, buzz]).

:- end_tests(fizzbuzz).