-- Hangman game, Lecture 3A
-- 2011-11-07
-- Dave Sands

import Data.List
import System.Random(randomRIO)

wordList = "/usr/share/dict/words" -- mac OS X
sizeWordList = 234935
guessLimit = 10

main :: IO()
main = do w <- getWord
          gameLoop w ""

getWord :: IO String 
getWord = 
        do ws <- readFile wordList
           n <- randomRIO (0,sizeWordList)
           return $ lines ws !! n 

gameLoop w g | loose     = looser w g  
             | win       = winner w g
             | otherwise = 
             do putStrLn [if c `elem` g  then c else '_'| c <- w]
                putStrLn "Please type one or more characters"
                s <- getLine
                gameLoop w (g `union` s)
  where win   = all (`elem` g) w
        loose = length (g \\ w) >= guessLimit

winner w g = putStrLn $ "Well done! You guessed " ++ w ++ " in " 
                         ++ show (length g) ++ " guesses"
looser w g = putStrLn $ "You die. The word was " ++ w