part2.pi

import util.

main =>
  Input = read_file_lines(),
  render(Input),
  G = update(Input, 100),
  println("\n"),
  println(count_lit(G)).

render(G) => println(join(G, "\n")).

count_lit(G) = R =>
  S = flatten(G),
  R = length(S) - length(delete_all(S, '#')).

update(G, 0) = G.
update(G, T) = R =>
  H = length(G),
  W = length(G[1]),
  X = new_array(W,H),
  % stuck on...
  G[1,1] := '#',
  G[1,W] := '#',
  G[H,1] := '#',
  G[H,W] := '#',

  foreach(J in 1..H)
    foreach(I in 1..W)
      Neighbours = 0,
      foreach(R in -1..1)
        foreach(C in -1..1)
          if(not(R == 0 && C == 0) && I+C > 0 && J+R > 0 && I+C <= W && J+R <= H) then
            Neighbours := Neighbours + cond(G[J+R,I+C] == '#', 1, 0)
          end,
        end,
      end,

      X[J,I] := cond(G[J,I] == '#',
          cond((Neighbours == 2 || Neighbours == 3), '#', '.'),
          cond(Neighbours == 3, '#', '.')
        )
    end
  end,

  % stick lights on again
  X[1,1] := '#',
  X[1,W] := '#',
  X[H,1] := '#',
  X[H,W] := '#',

  X2 = map(to_list, X.to_list()),
  print("\n<    "),
  print(T),
  println("    >\n"),
  % render(X2),
  R = update(X2, T-1).