Chmod.elm

-- for people too lazy to read the chmod man page
import Graphics.Input as Input
import Window

scene : (Int, Int) -> Element -> [Element] -> Element
scene (w, h) strInput strVal = flow down
  [ container w 100 topLeft strInput,
    container w (h - 100) topLeft (case strVal of 
      [] -> plainText "wtf"
      xs -> flow down (map (width 200) xs))]

fmapM : (a -> b) -> Maybe a -> Maybe b
fmapM f v = case v of
              Nothing -> Nothing
              Just v -> Just (f v)

getSources : Signal String -> Signal [Element]
getSources str = flip lift str (mkHex 0)

mkHex : Int -> String -> [Element]
mkHex dep y = case y of
            [] -> []
            (x::xs) -> (justs [(val (readInt [x]) dep)]) ++ (mkHex (dep + 1) xs)

val : Maybe Int -> Int -> Maybe Element
val x dep = case x of
          Just v -> fmapM plainText (whatMean v dep)
          Nothing -> Nothing

whatMean : Int -> Int -> Maybe String
whatMean x dep = let colN = fmapM (\x -> x ++ " - ") (colName dep)
                     xs n = foldl catStrs n vs
                     vs = [cWorld x, cGroup x, cUser x, cNone x]
             in case colN of
                   Nothing -> Nothing
                   Just vz -> if | length (xs vz) == 0 -> Nothing
                                 | otherwise -> Just (xs vz)

colName : Int -> Maybe String
colName x = if | x == 0 -> Just "User"
               | x == 1 -> Just "Group"
               | x == 2 -> Just "World"
               | otherwise -> Nothing

catStrs : Maybe String -> String -> String
catStrs x s = case x of
            Just v -> s ++ v
            Nothing -> s

cWorld : Int -> Maybe String
cWorld x = if | x `div` 4 == 1 -> Just "r"
              | otherwise -> Nothing
cGroup : Int -> Maybe String
cGroup x = if | x `rem` 4 `div` 2 == 1 -> Just "w"
              | otherwise -> Nothing
cUser : Int -> Maybe String
cUser x = if | x `rem` 4 `rem` 2 `div` 1 == 1 -> Just "x"
             | otherwise -> Nothing
cNone : Int -> Maybe String
cNone x = if | x == 0 -> Just "none"
             | otherwise -> Nothing

(strInput, strs) = Input.field "Permission string"

main = scene <~ Window.dimensions
              ~ strInput
              ~ getSources (dropRepeats strs)