module Main where

import           Data.Aeson
import qualified Data.ByteString.Lazy  as Bl
import qualified Text.Eros.Client      as Erosc
import qualified Text.Eros.Client.JSON as ErosJson
import           System.Exit
import qualified System.IO as Io


-- |So, this is the main function. Whoop de doo.  It sends the contents
-- of 'StdIO.stdin' to runBtStr.
--
-- Eventually, I'll add in command line argument parsing, and then we'll
-- have a use for the 'EroscOptions' type.
main :: IO ()
main = runBtStr =<< Bl.hGetContents Io.stdin

-- |attempt to 'eitherDecode' the user input
runBtStr :: Bl.ByteString -> IO ()
runBtStr inputBt = do
  let eitherJson = (eitherDecode inputBt) :: Either String Erosc.ClientInput
  case eitherJson of
    Left msg      -> Bl.hPutStr Io.stderr (encode msg) >> exitFailure
    Right ecInput -> runInput ecInput

-- |This takes the 'Erosc.ClientInput' thing and processes it.
runInput :: Erosc.ClientInput -> IO ()
runInput ipt = do
  result <- Erosc.processClientInput ipt
  let conf         = Erosc.configuration ipt
      outfpaths    = Erosc.outputFiles conf
      jsonText     = ErosJson.encode result conf
      writeOutputs = mapM_ (\fpath -> Bl.writeFile fpath jsonText) outfpaths
  if (Erosc.quiet conf)
    then writeOutputs >> exitSuccess
    else Bl.hPutStr Io.stdout jsonText >> writeOutputs >> exitSuccess