module Main where

import System.Environment (getArgs)
import System.Exit (exitFailure, exitSuccess)
import System.IO (hPutStrLn, stderr)
import qualified Data.ByteString.Lazy.Char8 as BL

import FWL.Parser  (parseFile)
import FWL.Pretty  (prettyProgram)
import FWL.Check   (checkProgram)
import FWL.Compile (compileToJson)

main :: IO ()
main = do
  args <- getArgs
  case args of
    ["check",   fp] -> runCheck   fp
    ["compile", fp] -> runCompile fp
    ["pretty",  fp] -> runPretty  fp
    _ -> do
      putStrLn "Usage: fwlc <command> <file.fwl>"
      putStrLn "  check   <file>   -- parse and static-check"
      putStrLn "  compile <file>   -- emit nftables JSON to stdout"
      putStrLn "  pretty  <file>   -- parse and re-print"
      exitFailure

runCheck :: FilePath -> IO ()
runCheck fp = do
  result <- parseFile fp
  case result of
    Left err -> hPutStrLn stderr ("Parse error:\n" ++ show err) >> exitFailure
    Right prog -> do
      let errs = checkProgram prog
      if null errs
        then putStrLn "OK" >> exitSuccess
        else mapM_ (hPutStrLn stderr . show) errs >> exitFailure

runCompile :: FilePath -> IO ()
runCompile fp = do
  result <- parseFile fp
  case result of
    Left err -> hPutStrLn stderr ("Parse error:\n" ++ show err) >> exitFailure
    Right prog -> do
      let errs = checkProgram prog
      if null errs
        then BL.putStrLn (compileToJson prog)
        else mapM_ (hPutStrLn stderr . ("Check error: " ++) . show) errs >> exitFailure

runPretty :: FilePath -> IO ()
runPretty fp = do
  result <- parseFile fp
  case result of
    Left err -> hPutStrLn stderr ("Parse error:\n" ++ show err) >> exitFailure
    Right prog -> putStr (prettyProgram prog)