% vim: syntax=prolog

:- use_module(library(clpfd)).
:- use_module(library(dcg/basics)).

ip4(A, B, C, D, Addr) :- 
  A in 0..255,
  B in 0..255,
  C in 0..255,
  D in 0..255,
  Addr #= (A * 2^24 + B * 2^16 + C * 2^8 + D).

ip4_range(ip4(_, _, _, _), Range) :- 
  Range in 0..32.

ip_format(ip4(A, B, C, D, _), Str) :-
  format(string(Str), "~w.~w.~w.~w", [A, B, C, D]).

ip_format(ip4_range(ip4(A, B, C, D, _), Range), Str) :-
  format(string(Str), "~w.~w.~w.~w/~w", [A, B, C, D, Range]).

ip4_g(A, B, C, D) --> ip4_num(A), ".", ip4_num(B), ".", ip4_num(C), ".", ip4_num(D).
ip4_num(D) --> integer(D), { D >= 0, D =< 255 }.
ipx(A) --> integer(A).

ip_parse(Str, Obj) :-
  string_codes(Str, Codes),
  phrase(ip4_g(A, B, C, D), Codes),
  Obj = ip4(A, B, C, D).

:- begin_tests(lists).
:- use_module(library(lists)).

test(ip4) :-
  ip4(127, 0, 0, 1, A),
  assertion(A =:= (127 * 2**24 + 1)).

test(ip_format) :-
  ip_format(ip4(127, 0, 0, 1, _), Str),
  assertion(Str == "127.0.0.1").

test(ip_format) :-
  Ip = ip4_range(ip4(192, 168, 0, 0, _), 24),
  ip_format(Ip, Str),
  assertion(Str == "192.168.0.0/24").

test(ip_parse) :-
  ip_parse("1.2.3.4", Ip),
  assertion(Ip == ip4(1, 2, 3, 4)).

:- end_tests(lists).