-module(xo).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([next_turn/1, start/1, play_again/2, get_random_move/2, play/2, get_smart_moves/1, map/2, to_string/1, to_state/1]).
-export_type([player/0, game/0, play_error/0, rules/0, state/0, outcome/0]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

-type player() :: x | o.

-opaque game() :: {playing,
        player(),
        player(),
        list({{integer(), integer()}, xo@internal@mark:mark()})} |
    {game_over,
        player(),
        player(),
        list({{integer(), integer()}, xo@internal@mark:mark()}),
        xo@internal@referee:outcome()}.

-type play_error() :: {out_of_bounds, {integer(), integer()}} |
    {occupied, {integer(), integer()}} |
    game_already_ended.

-type rules() :: {rules, boolean(), boolean()}.

-type state() :: {state, player(), player(), outcome()}.

-type outcome() :: {win,
        player(),
        list({{integer(), integer()},
            {integer(), integer()},
            {integer(), integer()}})} |
    {draw, player()} |
    undecided.

-file("src/xo.gleam", 17).
-spec next_turn(player()) -> player().
next_turn(Player) ->
    case Player of
        x ->
            o;

        o ->
            x
    end.

-file("src/xo.gleam", 32).
?DOC(" Start a new game such that the given player plays first.\n").
-spec start(player()) -> game().
start(Player) ->
    {playing, Player, Player, []}.

-file("src/xo.gleam", 85).
?DOC(" Reset the game while respecting the given rules.\n").
-spec play_again(game(), rules()) -> game().
play_again(Game, Rules) ->
    case Game of
        {playing, First, _, _} ->
            start(First);

        {game_over, First@1, Turn, _, Outcome} ->
            case Outcome of
                {win, _, _} ->
                    case erlang:element(2, Rules) of
                        true ->
                            start(Turn);

                        false ->
                            start(next_turn(Turn))
                    end;

                {draw, _} ->
                    case erlang:element(3, Rules) of
                        true ->
                            start(next_turn(Turn));

                        false ->
                            start(First@1)
                    end
            end
    end.

-file("src/xo.gleam", 150).
-spec tile_to_string(gleam@option:option(player())) -> binary().
tile_to_string(Tile) ->
    case Tile of
        {some, x} ->
            <<"x"/utf8>>;

        {some, o} ->
            <<"o"/utf8>>;

        none ->
            <<"."/utf8>>
    end.

-file("src/xo.gleam", 160).
-spec get_random_move(game(), prng@seed:seed()) -> {ok,
        {{integer(), integer()}, prng@seed:seed()}} |
    {error, nil}.
get_random_move(Game, Seed) ->
    case Game of
        {playing, _, _, Board} ->
            xo@internal@ai:get_random_move(Board, Seed);

        _ ->
            {error, nil}
    end.

-file("src/xo.gleam", 176).
-spec player_to_mark(player()) -> xo@internal@mark:mark().
player_to_mark(Player) ->
    case Player of
        x ->
            x;

        o ->
            o
    end.

-file("src/xo.gleam", 47).
-spec play(game(), {integer(), integer()}) -> {ok, game()} |
    {error, play_error()}.
play(Game, Pos) ->
    case Game of
        {playing, First, Turn, Board} ->
            case xo@internal@board:in_bounds(Pos) of
                true ->
                    case xo@internal@board:is_open(Board, Pos) of
                        true ->
                            Mark = player_to_mark(Turn),
                            Next_board = xo@internal@board:put(Board, Pos, Mark),
                            case xo@internal@referee:decide(Next_board, Mark) of
                                none ->
                                    {ok,
                                        {playing,
                                            First,
                                            next_turn(Turn),
                                            Next_board}};

                                {some, Outcome} ->
                                    {ok,
                                        {game_over,
                                            First,
                                            Turn,
                                            Next_board,
                                            Outcome}}
                            end;

                        false ->
                            {error, {occupied, Pos}}
                    end;

                false ->
                    {error, {out_of_bounds, Pos}}
            end;

        _ ->
            {error, game_already_ended}
    end.

-file("src/xo.gleam", 167).
-spec get_smart_moves(game()) -> list({integer(), integer()}).
get_smart_moves(Game) ->
    case Game of
        {playing, _, Turn, Board} ->
            xo@internal@ai:get_smart_moves(Board, player_to_mark(Turn));

        _ ->
            []
    end.

-file("src/xo.gleam", 183).
-spec mark_to_player(xo@internal@mark:mark()) -> player().
mark_to_player(Mark) ->
    case Mark of
        x ->
            x;

        o ->
            o
    end.

-file("src/xo.gleam", 139).
-spec map(
    game(),
    fun(({integer(), integer()}, gleam@option:option(player())) -> GVK)
) -> list(GVK).
map(Game, F) ->
    xo@internal@board:map(
        erlang:element(4, Game),
        fun(Pos, Mark_tile) ->
            F(Pos, gleam@option:map(Mark_tile, fun mark_to_player/1))
        end
    ).

-file("src/xo.gleam", 145).
-spec to_string(game()) -> binary().
to_string(Game) ->
    _pipe = map(Game, fun(_, Tile) -> tile_to_string(Tile) end),
    gleam@string:concat(_pipe).

-file("src/xo.gleam", 190).
-spec location_to_line(xo@internal@referee:location()) -> {{integer(),
        integer()},
    {integer(), integer()},
    {integer(), integer()}}.
location_to_line(Location) ->
    case Location of
        r1 ->
            {{0, 0}, {0, 1}, {0, 2}};

        r2 ->
            {{1, 0}, {1, 1}, {1, 2}};

        r3 ->
            {{2, 0}, {2, 1}, {2, 2}};

        c1 ->
            {{0, 0}, {1, 0}, {2, 0}};

        c2 ->
            {{0, 1}, {1, 1}, {2, 1}};

        c3 ->
            {{0, 2}, {1, 2}, {2, 2}};

        d1 ->
            {{0, 0}, {1, 1}, {2, 2}};

        d2 ->
            {{0, 2}, {1, 1}, {2, 0}}
    end.

-file("src/xo.gleam", 122).
-spec to_state(game()) -> state().
to_state(Game) ->
    case Game of
        {playing, First, Turn, _} ->
            {state, First, Turn, undecided};

        {game_over, First@1, Turn@1, _, Outcome} ->
            {state, First@1, Turn@1, case Outcome of
                    {win, Mark, Locations} ->
                        {win,
                            mark_to_player(Mark),
                            gleam@list:map(Locations, fun location_to_line/1)};

                    {draw, Mark@1} ->
                        {draw, mark_to_player(Mark@1)}
                end}
    end.