GameState.hs

module GameState
    where

import Board
import Helper (getSpace, subSet)

checkGameState :: Grid -> (Bool, Maybe Space)
checkGameState board 
    | checkWin (getSpace board X) = (True, Just X) -- X Wins
    | checkWin (getSpace board O) = (True, Just O) -- O Wins
    | fullBoard board = (False, Just Empty)-- Draw 
    | otherwise = (False, Nothing) -- Game Ongoing
    where
        fullBoard :: Grid -> Bool
        fullBoard (Square Empty End) = False 
        fullBoard (Square _ End) = True
        fullBoard (Square x xs)
            | x == Empty = False 
            | otherwise = fullBoard xs

        checkWin :: [Int] -> Bool
        checkWin [] = False
        checkWin x
            | winByRow x || winByColumn x || winByCross x = True
            | otherwise = False
            where
                winByRow :: [Int] -> Bool
                winByRow x = subSet [0,1,2] x || subSet [3,4,5] x || subSet [6,7,8] x

                winByColumn :: [Int] -> Bool
                winByColumn x = subSet [0,3,6] x || subSet [1,4,7] x || subSet [2,5,8] x

                winByCross :: [Int] -> Bool
                winByCross x = subSet [0,4,8] x || subSet [2,4,6] x