module Main where

import System.Environment (getArgs)
import System.Exit (exitFailure, exitSuccess)
import System.IO (hPutStrLn, stderr)

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

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 do
          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 putStrLn (compileToJson prog)
        else do
          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)