module Fun.Compiler where

import           Control.Exception
import           Fun.Parser
import           Fun.Tree
import           System.Exit
import           System.IO

genTrace :: [String] -> String
genTrace xs =
  "Trace of expectance: "
    ++ foldr (\a b -> a ++ if b == "" then b else " -> " ++ b) "" xs

parse :: String -> Either String Program -- TODO: Should be tree
parse file = case program file of
  Left a -> Left $ "Parse fault!\n" ++ case a of
    State [] Nothing    -> "No context available"
    State t  Nothing    -> genTrace t
    State [] (Just str) -> "Around here:\n" ++ str
    State t  (Just str) -> genTrace t ++ "\nAround here:\n" ++ str
  Right (a, b) -> Right a

compile :: String -> IO ()
compile path = do
  file <- try $ readFile path
  case file of
    Left  exception -> print (exception :: IOError)
    Right file      -> case parse file of
      Left err -> do
        hPutStrLn stderr err
        exitWith (ExitFailure 1)
      Right block -> putStrLn . show $ block