:- use_module(library(pio)).
:- initialization(main, main).

main([FileName|_]) :-
    input(FileName, Input),
    hashes(Input, Hash),
    writef('Answer=%t\n', [Hash]).

hashes(Strs, Hash) :-
    concurrent_maplist(reverse, Strs, RStrs),
    concurrent_maplist(hash, RStrs, Hashes),
    sum_list(Hashes, Hash).

hash([], 0).
hash([C|Str], Hash) :- hash(Str, Prev), Hash is (Prev + C)*17 mod 256.

% Input stuff
input(FileName, Input) :- phrase_from_file(string(Input), FileName).

string([]) --> (eos; "\n"), !.
string([Item|Items]) --> item(Item), string(Items).

item([]) --> (","; "\n"; eos), !.
item([C|Chars]) --> [C], item(Chars).

eos([], []).