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90 lines
2.5 KiB
Erlang
90 lines
2.5 KiB
Erlang
%% @author Correl Roush <correl@gmail.com>
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%%
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%% @doc Riichi Mahjong library.
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%%
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%% @headerfile "../include/riichi.hrl"
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-module(riichi_hand).
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-include("../include/riichi.hrl").
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-export([find/1,
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tiles/1,
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head/1,
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is_complete/1,
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waits/1]).
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-spec find
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(hand()) -> [hand()];
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([tile()]) -> [hand()].
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find(#hand{} = Hand) ->
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find(lists:sort(tiles(Hand)));
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find(Tiles) ->
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find(lists:sort(Tiles), #hand{}, []).
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-spec find([tile()], hand(), [hand()]) -> [hand()].
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find([], Hand, Possible) ->
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[Hand|Possible];
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find(Tiles, Hand = #hand{tiles=HT, melds=HM}, Possible) ->
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case Tiles of
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[T, T, T|Rest] ->
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find(Rest, Hand#hand{melds=[#meld{type=pon, tiles=[T, T, T]}|HM]}, Possible);
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_ ->
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[]
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end ++
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case Tiles of
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[T, T|Rest] ->
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find(Rest, Hand#hand{melds=[#meld{type=pair, tiles=[T, T]}|HM]}, Possible);
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_ ->
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[]
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end ++
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case lists:sort(sets:to_list(sets:from_list(Tiles))) of
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[T1 = #tile{value=V1, suit=S}, T2 = #tile{value=V2, suit=S}, T3 = #tile{value=V3, suit=S}|_] when
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is_integer(V1) andalso
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[V1, V2, V3] =:= [V1, V1 + 1, V1 + 2] ->
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find(Tiles -- [T1, T2, T3], Hand#hand{melds=[#meld{type=chii, tiles=[T1, T2, T3]}|HM]}, Possible);
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_ ->
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[]
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end ++
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case Tiles of
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[T|Rest] ->
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find(Rest, Hand#hand{tiles=[T|HT]}, Possible)
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end.
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-spec tiles(hand() | meld()) -> [tile()].
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tiles(#hand{tiles=Tiles, melds=Melds}) ->
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lists:flatten([TS || #meld{tiles=TS} <- Melds]) ++ Tiles;
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tiles(#meld{tiles=Tiles}) ->
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Tiles.
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-spec head(hand()) -> meld() | none.
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head(#hand{melds=Melds}) ->
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case [M || M = #meld{type=pair} <- Melds] of
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[Pair|_] ->
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Pair;
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[] ->
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none
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end.
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-spec is_complete(hand()) -> boolean().
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is_complete(#hand{tiles=[], melds=Melds}=Hand) ->
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Pairs = [M || M <- Melds, M#meld.type =:= pair],
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case length(Pairs) of
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1 ->
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% Four mentsu + 1 pair = 5 sets
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length(Melds) =:= 5;
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7 ->
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% Must be seven *unique* pairs
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yaku:chiitoitsu(#game{}, #player{hand=Hand});
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_ ->
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false
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end;
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is_complete(#hand{}=Hand) ->
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yaku:kokushi_musou(#game{}, #player{hand=Hand}).
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-spec waits(hand()) -> [tile()].
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waits(#hand{}=Hand) ->
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[T || T <- ?TILES,
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0 < length([H || H <- find(tiles(Hand) ++ [T]),
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is_complete(H)])].
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