-module(link).

-compile(export_all).

main(Psi) ->
  {_, List} = generate(top, Psi),
  iolist_to_binary(List).

g(top) ->
  [
   [{intro}, idrather]
  ];
g(idrather) ->
  [
   [<<"I'd rather">>, action]
  ];
g(intro) ->
  [
   [adj_holy, [adj_holy], [adj], god, {adverb}, <<",">>]
  ];
g(action) ->
  [
   [<<"eat">>, substance],
   [<<"drink">>, substance, <<"smoothie">>],
   [<<"fuck">>, animal],
   [<<"take it from">>, animal]
  ];
g(subject) ->
  [
   [article, [adj], noun]
  ];
g(adverb) ->
  [
   [<<"in a bag of">>, substance]
  ];
g(animal) ->
  [
   [article, {adj}, n_animal]
  ];
g(n_animal) ->
  dict(["cow", "dog", "goat", "rooster"]);
g(god) ->
  dict(["baby Jesus", "Jesus", "God", "cow", "virgin Mary"]);
g(substance) ->
  [
   [{someones}, n_substance]
  ];
g(someones) ->
  [
   [animal, <<"='s">>],
   [god, <<"='s">>]
  ];
g(n_substance) ->
  dict(["piss", "shit", "jizz", "pee"]);
g(adj_holy) ->
  dict(["sweet", "holy", "almighty"]);
g(adj) ->
  [
   [<<", soaked in">>, substance, <<",">>],
   [substance, <<"=-flavored">>]
  |dict(["rotten", "rabid", "putrid", "dead", "deceased", "dead", "tap-dancing", "worm-infested"])
  ];
g(verb) ->
  dict(["eat", "fuck", "flagellate"]);
g(noun) ->
  dict(["goat", "dog", "granpa"]);
g(article) ->
  dict(["a"]);
g(A) ->
  [[atom_to_binary(A, utf8)]].

generate({_Optional}, 0)  ->
  %% When we run out of psihoza, we should not generate optional
  %% terms:
  {0, []};
generate({Optional}, Psi) ->
  case rand:uniform(2) of
    1 -> {Psi, []};
    2 -> generate(Optional, Psi)
  end;
generate([_], 0) ->
  {0, []};
generate([Repeat], Psi0) ->
  case rand:uniform(2) of
    1 -> {Psi0, []};
    2 ->
      {Psi1, Hd} = generate(Repeat, Psi0),
      {Psi, Tl} = generate([Repeat], Psi1),
      {Psi, [Hd|Tl]}
  end;
generate(Tree, Psi) when is_atom(Tree) ->
  Voretions = g(Tree),
  Pos = rand:uniform(length(Voretions)),
  Tokens = lists:nth(Pos, Voretions),
  lists:foldr(fun do_generate/2, {Psi, []}, Tokens);
generate(Terminal, _) when is_binary(Terminal) ->
  {1, [<<" ">>, Terminal]}.

do_generate(Term, {Psi0, Acc}) ->
  {Psi, Hd} = generate(Term, Psi0),
  {Psi, [Hd|Acc]}.

dict(L) ->
  [[list_to_binary(I)] || I <- L].