module PokerII where

import Data.List

data Rank = Two|Three|Four|Five|Six|Seven|Eight|Nine|Ten|J|Q|K|A

deriving (Eq, Ord, Enum, Show, Read)

data Suit = Spades|Hearts|Diamonds|Clubs

deriving (Eq, Show, Read) -- no ordering for poker

data Card = Card Rank Suit

deriving (Show, Read)

data Hand = Hd [Card]

instance Eq Card where

(Card rank1 _) == (Card rank2 _) = rank1 == rank2

instance Ord Card where

compare (Card rank1 _ ) (Card rank2 _)

| rank1 < rank2 = LT

| rank1 > rank2 = GT

| otherwise = EQ

isFlush [_] = True

isFlush ((Card _ suit1):(Card r suit2):cards)

| suit1 == suit2 = isFlush ((Card r suit2):cards)

| otherwise = False

isStraight cards = xs == [0,1,2,3,12] || inSequence xs

where xs = (sort [fromEnum rank | (Card rank _) <- cards])

inSequence [_] = True

inSequence (x:y:xs)

| (y-x) == 1 = inSequence (y:xs)

| otherwise = False

isStraightFlush cards = isStraight cards && isFlush cards

isRoyalFlush cards = isFlush cards && (sort [rank | (Card rank _) <- cards]) == [Ten .. A]