gchess

-module(gchess).
-compile([no_auto_import, nowarn_unused_vars]).

-export([main/0]).

-spec perft(gleam@erlang@process:subject(game:message()), integer()) -> integer().
perft(Game_actor, Depth) ->
    case Depth of
        0 ->
            1;

        _ ->
            Moves = game:all_legal_moves(Game_actor),
            Nodes@2 = gleam@list:fold(
                Moves,
                0,
                fun(Nodes, Move) ->
                    gleam@io:println(move:to_string(Move)),
                    game:apply_move(Game_actor, Move),
                    Nodes@1 = Nodes + perft(Game_actor, Depth - 1),
                    game:undo_move(Game_actor),
                    Nodes@1
                end
            ),
            Nodes@2
    end.

-spec main() -> nil.
main() ->
    Game_actor = game:new_game_from_fen(
        <<"rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8"/utf8>>
    ),
    game:print_board(Game_actor),
    _pipe = perft(Game_actor, 2),
    _pipe@1 = gleam@int:to_string(_pipe),
    gleam@io:println(_pipe@1).