module Bob (responseFor) where
import Data.Char ( isLetter, isSpace, isUpper )

responseFor :: String -> String
responseFor input
    | null text = "Na gut. Dann eben nicht!"
    | isShouting && isAsking = "Chill mal, ich bin da schon dran!"
    | isShouting = "Whoa, entspann dich!"
    | isAsking = "Klar."
    | otherwise = "Whatever."
  where
    text = filter (not . isSpace) input
    letters = filter isLetter text
    isShouting = all isUpper letters && any isUpper letters
    isAsking = last text == '?'