{-|
Module      : Kino.Misc
Description : Contains miscellaneous helper functions which do not fit elsewhere

Contains miscellaneous helper functions which do not fit elsewhere
-}

module Kino.Misc where

import Lens.Micro

import Kino.Types

infixl 3 !?
-- | Safe version of (!!)
(!?) :: [a] -> Int -> Maybe a
[]     !? _ = Nothing
(x:_)  !? 0 = Just x
(_:xs) !? n = xs !? (n-1)

infixl 0 $>
-- | Backwards function application
($>) :: a -> (a -> b) -> b
x $> f = f x

-- | Given a String, modify our state so that string
-- is displayed as a message, alternatively forcing
-- an exit after the message is aknowledged.
displayMessage :: AppS -> Bool -> String -> AppS
displayMessage s fatal msg = s & appMode     .~ Message
                               & appMessage  ?~ msg
                               & appContinue .~ not fatal