riichi/src/yaku.erl
2012-08-14 20:16:06 -04:00

181 lines
7.8 KiB
Erlang

%% @author Correl Roush <correl@gmail.com>
%%
%% @doc Riichi Mahjong library.
%%
%% @headerfile "../include/riichi.hrl"
-module(yaku).
-include("../include/riichi.hrl").
-export([yakuhai/2,
tanyao/2,
pinfu/2,
iipeikou/2,
chanta/2,
itsuu/2,
chiitoitsu/2,
san_shoku_doujun/2,
san_shoku_douko/2,
san_kan_tsu/2,
kokushi_musou/2,
ryuu_iisou/2,
dai_san_gen/2]).
%% @doc Counts the pons/kans of value tiles in a player's hand.
%% Value tiles include all of the dragons, plus the round wind and the player's seat wind.
-spec yakuhai(game(), player()) -> integer().
yakuhai(#game{round=Round}, #player{seat=Seat, hand=#hand{melds=Melds}}) ->
length(lists:filter(fun(#meld{type=Type, tiles=[T|_]}) ->
case {Type, T} of
{pair, _} ->
false;
{chii, _} ->
false;
{_, #tile{suit=wind, value=Round}} ->
true;
{_, #tile{suit=wind, value=Seat}} ->
true;
{_, #tile{suit=dragon}} ->
true;
_ ->
false
end
end,
Melds)).
%% @doc Returns true if the hand consists only of simple tiles.
%% Terminals, winds and dragons are not allowed.
-spec tanyao(game(), player()) -> boolean().
tanyao(#game{}, #player{hand=Hand}) ->
not lists:any(fun(T = #tile{}) ->
case T#tile.suit of
dragon ->
true;
wind ->
true;
_ ->
lists:member(T#tile.value, [1,9])
end
end,
riichi_hand:tiles(Hand)).
%% @doc Returns true for a no-points hand.
%% To qualify for pinfu, the hand must be fully concealed, contain no pons/kans,
%% contain no dragons, round winds or seat winds, and must be won on an open wait.
-spec pinfu(game(), player()) -> boolean().
pinfu(#game{round=Round}, #player{seat=Seat, hand=Hand=#hand{melds=Melds}, drawn={_, Drawn}}) ->
Closed = lists:all(fun(T) -> T#tile.from =:= draw end, riichi_hand:tiles(Hand)),
OpenWait = length(riichi_hand:waits(#hand{tiles=riichi_hand:tiles(Hand) -- [Drawn]})) > 1,
Chiis = length([M || M = #meld{type=chii} <- Melds]) =:= 4,
#meld{type=pair, tiles=[HeadTile,HeadTile]} = riichi_hand:head(Hand),
NonValuePair = HeadTile#tile.value =/= Round
andalso HeadTile#tile.value =/= Seat
andalso HeadTile#tile.suit =/= dragon,
Closed and OpenWait and Chiis and NonValuePair.
%% @doc Counts unique elements in a list
-spec count_unique(list()) -> list({term(), integer()}).
count_unique(L) ->
Unique = sets:to_list(sets:from_list(L)),
[{I, length(lists:filter(fun (X) ->
X == I
end,
L))}
|| I <- Unique].
%% @doc Returns true for a hand containing two identical straights in the same suit
%% Will NOT return true if there are more than two, as this yaku and ryanpeikou
%% are mutually exclusive.
-spec iipeikou(game(), player()) -> boolean().
iipeikou(#game{}, #player{hand=#hand{melds=Melds}}) ->
Chiis = [M || M = #meld{type=chii} <- Melds],
Counts = [C || {_, C} <- count_unique(Chiis)],
lists:max(Counts) > 1 andalso lists:max(Counts) < 4.
%% @doc Returns true for a Chanta hand
%% All melds and the pair must include a terminal or honor tile
-spec chanta(game(), player()) -> boolean().
chanta(#game{}, #player{hand=#hand{tiles=[], melds=Melds}}) ->
Sets = [[{T#tile.suit, T#tile.value} || T <- Tiles]
|| #meld{tiles=Tiles} <- Melds],
ChantaTiles = [{T#tile.suit, T#tile.value} || T <- (?TERMINALS ++ ?HONOURS)],
lists:all(fun(Tiles) ->
(Tiles -- ChantaTiles =/= Tiles)
end,
Sets).
%% @doc Returns true for an Itsuu hand
%% Hand must contain a 1-9 run in one suit
-spec itsuu(game(), player()) -> boolean().
itsuu(#game{}, #player{hand=#hand{tiles=[], melds=Melds}}) ->
Tiles = lists:flatten([TS || #meld{type=chii, tiles=TS} <- Melds]),
Runs = [lists:filter(fun(#tile{suit=S, value=V}) -> S =:= Suit end, Tiles)
|| Suit <- [man,sou,pin]],
lists:any(fun(TS) ->
sets:from_list([V || #tile{value=V} <- TS]) =:= sets:from_list(lists:seq(1,9))
end,
Runs).
%% @doc Returns true if the provided meld is present in the hand
%% in all three suits
-spec san_shoku(meld(), hand()) -> boolean().
san_shoku(#meld{tiles=Tiles}, #hand{melds=Melds}) ->
[V1, V2, V3] = [V || #tile{value=V} <- Tiles],
MeldTiles = [TS || #meld{tiles=TS} <- Melds],
TSV = fun(#tile{suit=S,value=V}) -> {S,V} end,
MeldValues = lists:map(fun(L) -> lists:map(TSV, L) end, MeldTiles),
lists:all(fun(M) -> lists:member(M, MeldValues) end,
[[{S, V1}, {S, V2}, {S, V3}]
|| S <- [pin, sou, man]]).
%% @doc Returns true for a San shoku doujun hand
%% Hand must contain the same sequence in all three suits
-spec san_shoku_doujun(game(), player()) -> boolean().
san_shoku_doujun(#game{}, #player{hand=#hand{melds=Melds}=Hand}) ->
Chiis = [M || #meld{type=chii} = M <- Melds],
lists:any(fun(M) -> san_shoku(M, Hand) end, Chiis).
%% @doc Returns true for a San shoku douko hand
%% Hand must contain the same triplet in all three suits
-spec san_shoku_douko(game(), player()) -> boolean().
san_shoku_douko(#game{}, #player{hand=#hand{melds=Melds}=Hand}) ->
Pons = [M || #meld{type=pon} = M <- Melds],
lists:any(fun(M) -> san_shoku(M, Hand) end, Pons).
%% @doc Returns true for a San kan tsu hand
%% Hand must contain three kans
san_kan_tsu(#game{}, #player{hand=#hand{melds=Melds}}) ->
Kans = [M || M = #meld{type=kan} <- Melds],
length(Kans) =:= 3.
%% @doc Returns true for a 7-pair hand.
-spec chiitoitsu(game(), player()) -> boolean().
chiitoitsu(#game{}, #player{hand=#hand{tiles=[], melds=Melds}})
when length(Melds) =:= 7 ->
Pairs = [S || S <- Melds, S#meld.type =:= pair],
length(Pairs) =:= 7 andalso sets:size(sets:from_list(Pairs)) =:= 7.
%% @doc Returns true for a 13 Orphans hand.
%% The hand must contain one each of every terminal and honour tile, plus one
%% additional tile matching any of the others in the hand.
-spec kokushi_musou(game(), player()) -> boolean().
kokushi_musou(#game{}, #player{hand=#hand{tiles=Tiles, melds=[#meld{type=pair, tiles=[T,T]}]}}) ->
not lists:any(fun(#tile{value=V}) ->
lists:member(V, lists:seq(2,8))
end,
[T|Tiles])
andalso sets:size(sets:from_list([T|Tiles])) =:= 13;
kokushi_musou(#game{}, #player{}) ->
false.
%% @doc Returns true for an all-green hand.
-spec ryuu_iisou(game(), player()) -> boolean().
ryuu_iisou(#game{}, #player{hand=Hand}) ->
Greens = sets:from_list([#tile{suit=sou, value=V} || V <- [2,3,4,6,8]] ++ [#tile{suit=dragon, value=green}]),
Tiles = sets:from_list(riichi_hand:tiles(Hand)),
sets:is_subset(Tiles, Greens).
%% @doc Returns true for a Big Three Dragons hand
-spec dai_san_gen(game(), player()) -> boolean().
dai_san_gen(#game{}, #player{hand=#hand{melds=Melds}}) ->
[green, red, white] =:= lists:usort([V || #meld{type=T, tiles=[#tile{suit=dragon, value=V}|_]} <- Melds,
lists:member(T, [pon, kan])]).