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

-export([main/0]).

-spec main() -> nil.
main() ->
    Game_actor = game_server:from_fen(
        <<"rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"/utf8>>
    ),
    game_server:print_board(Game_actor),
    _pipe = game_server:all_legal_moves(Game_actor),
    _pipe@1 = gleam@list:map(_pipe, fun move:to_string/1),
    gleam@list:each(_pipe@1, fun gleam@io:println/1),
    game_server:apply_move_uci(Game_actor, <<"e2e4"/utf8>>),
    game_server:print_board(Game_actor).

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

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