main.hs

import System.IO
import System.Environment
import Data.List
import Data.List.Split
import Data.Ord
import Automata
import Data.Maybe

trim :: Eq a => [a] -> [a] -> [a]
trim chs = dropWhileEnd (`elem` chs) . dropWhile (`elem` chs)

parse :: String -> (State, State, [(State, [(State, [State])])], [String])
parse str
  | '|' `elem` str = let
        [s,t] = splitOn "|" (trim " \r" str)
        parseTransition text = map words (splitOn "," text)
        
        state = trim " \r" (s \\ ">*")
        startState = if '>' `elem` s then state else ""
        finalState = if '*' `elem` s then state else ""
        transitions = [(h,t) | (h:t) <- parseTransition t]
      in
        (startState, finalState, [(state,transitions)], [])
  | otherwise = ("", "", [], words str)  -- assuming this is a word line


parseFA :: [(State, State, [(State, [(State, [State])])], [State])]
         -> (NFA State, [State])
parseFA parsed = 
  let 
    (startStates, finalStates, transitions, w) = unzip4 parsed
    table = concat transitions
    words = concat w
    parsedStates = keys table
    symbols = getAlphabet table
    fa = (NFA parsedStates symbols  startStates finalStates table)
  in 
    (fa, words)

processInput :: String -> [String] -> String
processInput s args =
  let
    (nd, parsedWords) = parseFA $ map parse (lines s) --parse nfa, convert to dfa
  in
     if any (\x -> length x /= 1) (states nd) then
      "Each state must be named by a character"
    else 
      let
        d = subsetConstruction nd
        (minimize, givenWords) = case args of
          "-m" : rest -> (True, rest)
          _ -> (False, args)

        dfa = if minimize then minimizeDFA d else d
        wordsToCheck = givenWords ++ parsedWords 

        str word = "is " ++ word ++ " accepted: " ++ show ( isAccepted dfa word)
        strAcc = map str wordsToCheck -- check input words

        out = unlines strAcc ++ show dfa
      in  
        out
      

main :: IO ()
main = do
  args <- getArgs
  case args of
    [] -> putStrLn "runghc main.hs <file_name> -m <words, if not present in the input file>"
    file:rest -> do 
      h <- openFile file ReadMode
      i <- hGetContents h
      putStrLn $ processInput i rest