#!/usr/bin/env runhaskell
import Data.ByteString
import Data.ByteString.Lazy.Char8 as BS hiding (filter,take,concat,map,drop,length)
import Data.Char
import System.Environment
import System.Exit
import System.IO

main :: IO ()
main = do args <- getArgs
          case args of
               []            -> showUsage
               ["-h"]        -> showUsage
               ["--help"]    -> showUsage
               ["--version"] -> showUsage
               [check]       -> do cf <- readF check
                                   nf <- readF "-"
                                   doCheck (BS.pack "_") cf nf
               [check, name] -> do cf <- readF check
                                   nf <- readF name
                                   doCheck (BS.pack "_") cf nf
               _             -> showUsage

showUsage :: IO ()
showUsage = do
                System.IO.hPutStr stderr "Usage    : check_attr_name <check_file> [<name_file>]\n"
                System.IO.hPutStr stderr "Version  : VERSION\n"
                System.IO.hPutStr stderr "Open usp Tukubai (LINUX+FREEBSD)\n"

doCheck :: BS.ByteString -> BS.ByteString -> BS.ByteString -> IO ()
doCheck ngstr cf nf = return ()

validate_check_digits :: [Char] -> IO ()
validate_check_digits digits = do
  digits <- readF "-"
  output <- validate_check_even_digits digits * 3 + validate_check_odd_digits digits
  BS.putStrLn output

validate_check_even_digits :: [Char] -> Int
validate_check_even_digits [] = 0
validate_check_even_digits (x1:(_:(x2:(_:xs)))) = (digitToInt x1) + (digitToInt x2) + validate_check_even_digits xs

validate_check_odd_digits :: [Char] -> Int
validate_check_odd_digits [] = 0
validate_check_odd_digits (_:odd_digits) = validate_check_even_digits odd_digits

readF :: String -> IO BS.ByteString
readF "-" = BS.getContents
readF f   = BS.readFile f