--1--
normalize :: String -> String
normalize text = if (any isDigit text) then "Error" else map toUpper (filter (\x -> x /= ' ' && x /= ',' && x/= '.') text)
--1--
--2--

encode :: [Char] -> Char -> Int -> Char
encode alphabet ch offset
     |not (isLetter ch) = error "error: unsupported symbol"
     |offset <0 && (index + offset < 0) = alphabet!!(abs(length alphabet + index + offset)`mod` length alphabet)
     |offset >0 && (index + offset >= length alphabet) = alphabet!!(abs(length alphabet - index - offset) `mod` length alphabet)
     |otherwise = alphabet!!(index + offset)
      where
        index = fromJust $ findIndex (\ x -> x == ch ) alphabet

--
encrypt :: [Char] -> Int -> String -> String
encrypt alphabet offset normalized = [encode alphabet x offset | x <- normalized]

decrypt :: [Char] -> Int -> String -> String
decrypt alphabet offset encrypted = [encode alphabet x (offset*(-1)) | x <- encrypted]
--2--
--3--
crackall :: [Char] -> String -> [String]
crackall alphabet encrypted = [encrypt alphabet x encrypted| x <- [1..(length alphabet-1)]]

substring :: String -> String -> Bool
substring sub str = isInfixOf sub str

crackcandidates :: [Char] -> [String] -> String -> [String]
crackcandidates alphabet commonwords encrypted =
       filter(\x -> helper5 commonwords x == True ) (crackall alphabet encrypted)
       where
            helper5 :: [String] -> String -> Bool
            helper5 commonwords encrypted = True `elem` [substring x encrypted| x<-commonwords ]
--3--
--4--
polyencrypt :: [Char] -> Int -> Int -> Int -> String -> String
polyencrypt alphabet offset step blockSize normalized
 |normalized == [] = []
 |otherwise = encrypt alphabet offset (take blockSize normalized) ++ polyencrypt alphabet (offset+step) step blockSize (drop blockSize normalized)
polydecrypt :: [Char] -> Int -> Int -> Int -> String -> String
polydecrypt alphabet offset step blockSize encrypted
  |encrypted == [] = []
  |otherwise = decrypt alphabet (offset) (take blockSize encrypted) ++ polydecrypt alphabet (offset+step) step blockSize (drop blockSize encrypted)
--4--
--5--
enigmaencrypt :: [Char] -> [Rotor] -> String -> String
enigmaencrypt alphabet rotors normalized
 |rotors == [] = normalized
 |otherwise = enigmaencrypt alphabet (drop 1 rotors) (polyencrypt alphabet (getOffset (take 1 rotors)) (getStep (take 1 rotors)) (getBlockSize (take 1 rotors)) normalized)

enigmadecrypt :: [Char] -> [Rotor] -> String -> String
enigmadecrypt alphabet rotors normalized
  |rotors == [] = normalized
  |otherwise = enigmadecrypt alphabet (drop 1 rotors) (polydecrypt alphabet (getOffset (take 1 rotors)) (getStep (take 1 rotors)) (getBlockSize (take 1 rotors)) normalized)

type Rotor = (Int,Int,Int)
getOffset :: [Rotor] -> Int
getOffset [(r, _,_)] = r
getStep :: [Rotor] -> Int
getStep [(_,s,_)] = s
getBlockSize :: [Rotor] -> Int
getBlockSize [(_,_,b)] = b
--5--