From d3220e1906c82eeb10b8c24bc9cba1cb54dde4b0 Mon Sep 17 00:00:00 2001
From: Correl Roush <correl@gmail.com>
Date: Fri, 10 Aug 2012 20:42:52 -0400
Subject: [PATCH] Chanta

---
 src/yaku.erl               | 13 +++++++++++++
 test/riichi_yaku_tests.erl |  8 ++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/yaku.erl b/src/yaku.erl
index aefd827..724ff78 100644
--- a/src/yaku.erl
+++ b/src/yaku.erl
@@ -12,6 +12,7 @@
          tanyao/2,
          pinfu/2,
          iipeikou/2,
+         chanta/2,
          chiitoitsu/2,
          kokushi_musou/2,
          ryuu_iisou/2,
@@ -87,6 +88,18 @@ iipeikou(#game{}, #player{hand=#hand{melds=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 a 7-pair hand.
 -spec chiitoitsu(game(), player()) -> boolean().
 chiitoitsu(#game{}, #player{hand=#hand{tiles=[], melds=Melds}})
diff --git a/test/riichi_yaku_tests.erl b/test/riichi_yaku_tests.erl
index d7d6cd0..c57dec8 100644
--- a/test/riichi_yaku_tests.erl
+++ b/test/riichi_yaku_tests.erl
@@ -44,6 +44,14 @@ iipeikou_test() ->
                         #meld{type=chii, tiles=[#tile{suit=man, value=V} || V <- [6,7,8]]}]},
     ?assertEqual(true, yaku:iipeikou(#game{}, #player{hand=Hand, drawn={tsumo, #tile{suit=sou, value=6}}})).
 
+chanta_test() ->
+    Hand = #hand{melds=[#meld{type=pair, tiles=lists:duplicate(2, #tile{suit=dragon, value=red})},
+                        #meld{type=chii, tiles=[#tile{suit=pin, value=V} || V <- [1,2,3]]},
+                        #meld{type=pon,  tiles=[#tile{suit=sou, value=V} || V <- [1,1,1]]},
+                        #meld{type=pon,  tiles=[#tile{suit=sou, value=V} || V <- [9,9,9]]},
+                        #meld{type=chii, tiles=[#tile{suit=man, value=V} || V <- [7,8,9]]}]},
+    ?assertEqual(true, yaku:chanta(#game{}, #player{hand=Hand, drawn={tsumo, #tile{suit=dragon, value=red}}})).
+
 chiitoitsu_test() ->
     Hand = #hand{melds=[#meld{type=pair, tiles=lists:duplicate(2, #tile{suit=pin, value=V})} || V <- lists:seq(1,7)]},
     ?assertEqual(true, yaku:chiitoitsu(#game{}, #player{hand=Hand})).