module Main where
import Data.List

vToDot :: String -> String
vToDot ls = "digraph {\n" ++ (snd $ vToDotP (lines ls, "")) ++ "}\n"

type Parser = ([String], String) -> ([String], String)

vToDotP :: Parser
vToDotP ([], t) = ([], t)
vToDotP (l:ls, t) = case (isPrefixOf "package" l) && (isInfixOf "unusable" l) of
    True  -> vToDotP $ unusableP (l:ls, t)
    False -> vToDotP (ls, t)

unusableP :: Parser
unusableP (l:ls, t) = (sls, t ++ ('\n' : l') ++ "{\n" ++ st ++ "\n  }\n")
    where (sls, st) = spacesP (ls, t)
          l' =  '"' : (words l !! 1) ++ "\" -> "

spacesP :: Parser
spacesP (l:ls, _) = case (isPrefixOf " " l) of
    True   -> (ls,  wrap  l)
    False  -> (l:ls, "")
  where wrap xs = intercalate ",\n" $ map (\x -> "  \"" ++ x ++ "\"") (words xs)

main :: IO ()      
main = interact  vToDot