import System.IO
import System.Random

-- scegli una riga a caso dal file
randomline :: StdGen -> [String] -> String
randomline g l = l' !! i
 where
   l' = [x | x <- l, not(null(x))]
   i = fst $ randomR (0, length l' - 1) g

-- controlla se la lettera e` stata indovinata
ismatch :: (Char, Char) -> Char -> Bool
ismatch x c = snd x == c && fst x == '_'

-- calcola nuovo stato
newstatus :: [(Char, Char)] -> Char -> [(Char, Char)]
newstatus s c = [if ismatch x c then (snd(x),snd(x)) else x | x <- s]

-- chiedi input e prova finche` non e` tutto indovinato
trials :: [(Char, Char)] -> IO ()
trials status = do
 nc <- getChar
 --let newstatus = [if ismatch c n then (snd(c),snd(c)) else c | c <- status]
 let ns = newstatus status nc
 putStrLn [fst x | x <- ns]
 if all (==True) [fst(x) == snd(x) | x <- ns] then
   return ()
 else
   trials ns

--------------------------------------------------------
main = do
 fc <- readFile "pallotron"
 gen <- getStdGen
 let target = randomline gen (lines fc)
 let start = take (length target) (repeat '_')
 putStrLn "Indovina, stronzo!"
 trials $ zip start target
 putStrLn ("Esatto, era proprio " ++ target)