From cc76a42320871e34a52c84e0509273f21232b5c4 Mon Sep 17 00:00:00 2001
From: Tom Alexandrowicz <talexand@thoughtworks.com>
Date: Wed, 14 Nov 2012 19:28:04 -0500
Subject: [PATCH] moar pokers

---
 poker_hands.erl       | 36 +++++++++++++++++++++++++++++++++---
 poker_hands_tests.erl | 31 +++++++++++++++++++++++++------
 2 files changed, 58 insertions(+), 9 deletions(-)

diff --git a/poker_hands.erl b/poker_hands.erl
index de24f26..df5931d 100644
--- a/poker_hands.erl
+++ b/poker_hands.erl
@@ -1,7 +1,37 @@
 -module(poker_hands).
--export([sum/1, rank/1]).
+-export([card/1, rank/1, hand/1, highcard/1, flush/1, straight/1, straight_flush/1]).
 
-sum([X|R]) -> X + sum(R);
-sum([]) -> 0.
+
+string_to_suit($H) -> h;
+string_to_suit($D) -> d;
+string_to_suit($C) -> c;
+string_to_suit($S) -> s.
+
+string_to_rank(N) ->
+	string:str("123456789TJQKA",[N]).
+
+card([X,Y]) -> {string_to_rank(X),string_to_suit(Y)}.
 
 rank({X,_}) -> X.
+
+hand([X,Y]) -> [card([X,Y])];
+hand([X,Y,32|R]) ->
+	[card([X,Y])] ++ hand(R).
+
+% [{2, h}, {3, s}, {4, s}, {5, s}]
+highcard(L) ->
+	lists:max(lists:map(fun rank/1, L)).	
+
+flush([{_,S},{_,S},{_,S},{_,S},{_,S}]) -> true;
+flush(_) -> false.
+
+straight_sorted([{R1,_}, {R2,_}]) -> R2 - R1 =:= 1;
+straight_sorted([{R1,_}, {R2,_} = C|Xs]) when R2 - R1 =:= 1 ->
+	straight_sorted([C|Xs]);
+straight_sorted(_) -> false.
+
+straight(L) ->
+	straight_sorted(lists:sort(L)).
+
+straight_flush(L) ->
+	true.
diff --git a/poker_hands_tests.erl b/poker_hands_tests.erl
index 9261045..ab554df 100644
--- a/poker_hands_tests.erl
+++ b/poker_hands_tests.erl
@@ -1,11 +1,30 @@
 -module(poker_hands_tests).
 -include_lib("eunit/include/eunit.hrl").
+-import(poker_hands, [card/1, rank/1, hand/1, highcard/1, flush/1, straight/1, straight_flush/1]).
 
-% sum_test() ->
-%     ?assertEqual(0, poker_hands:sum([])),
-%     ?assertEqual(0, poker_hands:sum([0])),
-%     ?assertEqual(6, poker_hands:sum([1,2,3,4,-4])).
+card_test() ->
+	?assertEqual({3, h}, card("3H")),
+	?assertEqual({2, h}, card("2H")),
+	?assertEqual({13, h}, card("KH")).
 
 rank_test() ->
-	?assertEqual(2, poker_hands:rank({2, h})),
-	?assertEqual(3, poker_hands:rank({3, h})).
\ No newline at end of file
+	?assertEqual(2, rank({2, h})),
+	?assertEqual(3, rank({3, h})).
+
+hand_test() ->
+	?assertEqual([{3, h}, {2, s}, {13, h}], hand("3H 2S KH")).
+
+highcard_test() ->
+	?assertEqual(10, highcard(hand("2H 3S 4D 5C TH"))),
+	?assertEqual(13, highcard(hand("2H 3S 4D KH 5C"))).	
+
+flush_test() ->
+	?assertEqual(true, flush(hand("2H 3H 6H 8H JH"))),
+	?assertEqual(false, flush(hand("2H 3C 6H 8H AC"))).
+
+straight_test() ->
+	?assertEqual(true, straight(hand("2H 3H 4H 5H 6H"))),
+	?assertEqual(false, straight(hand("2H 3H 8H 5H 6H"))).
+
+straight_flush_test() ->
+	?assertEqual(true, straight_flush(hand("2H 3H 4H 5H 6H"))).
\ No newline at end of file