Add ways to peek at hole card for insurance and dealer bj checks

cards.hs

@@ -3,6 +3,8 @@ module Cards
 , multiDeck
 , shuffle
 , shuffleIO
+, aceInTheHole
+, tenInTheHole
 , Card(..)
 , DownCard(..)
 , Suit(..)
@@ -101,3 +103,15 @@ shuffle (Deck d) g = Deck $ shuffle' d (length d) g
 
 shuffleIO :: StdDeck -> IO StdDeck
 shuffleIO d = liftM (shuffle d) newStdGen
+
+-- Legal ways to peek at the downcard
+-- Make sure to 'turn' it still
+aceInTheHole :: DownCard -> Bool
+aceInTheHole (DownCard c)  = isAce c
+  where isAce (Card Ace _) = True
+        isAce _            = False
+
+tenInTheHole :: DownCard -> Bool
+tenInTheHole (DownCard c) = isTen c
+  where isTen (Card r _)  | r >= Ten  = True
+                          | otherwise = False

dealer.hs

@@ -17,6 +17,15 @@ dealDealer d = let
 dealDealerS :: Deck d => State d DealerHand
 dealDealerS = liftS dealDealer
 
+revealHoleCard :: Deck d => DealerHand -> d -> (Hand, d)
+revealHoleCard (DealerHand a b) d = let
+  (a', d') = turn a d
+  h        = hand [a', b]
+  in (h, d)
+
+revealHoleCardS :: Deck d => DealerHand -> State d Hand
+revealHoleCardS = liftS . revealHoleCard
+
 -- Dealer only hits or stands
 data DealerAction = Hit | Stand
 
@@ -35,4 +44,10 @@ standS17 :: DealerStrategy
 standS17 = act . handTotal
   where act (HandValue Bust _)           = Stand
         act (HandValue _    n) | n <  18 = Hit
-                               | n >= 18 = Stand
+                               | n >= 18 = Stand
+
+offerInsurance :: DealerHand -> Bool
+offerInsurance (DealerHand _ c) = isTen c
+         where isTen (Card r _) | r == Ace  = False
+                                | r >= Ten  = True
+                                | otherwise = False

hands.hs

@@ -21,13 +21,10 @@ data DealerHand = DealerHand DownCard Card
 instance Show DealerHand where
   show (DealerHand _ c) = "DealerHand " ++ show c
 
-data HandStatus = Play
-                | Done
+data HandStatus = Play | Done
      deriving (Show)
 
-data HandType = Hard
-              | Soft
-              | Bust
+data HandType = Hard | Soft | Bust
      deriving (Show, Eq)
 
 data HandValue = HandValue HandType Int