{-|
Module      : Main
Description : The "glue" between spreadsheets and GraphViz
Copyright   : (c) Oleksandr Zhabenko, 2017-2023
License     : MIT
Maintainer  : oleksandr.zhabenko@yahoo.com
Stability   : Experimental

A program @gvti@ converts a specially formated @.csv@ file with a colon as a field separator obtained from the electronic table 
into a visualized by GraphViz graph in the one of the supported by GraphViz format. The proper GraphViz installation is required.
-}

{-# LANGUAGE NoImplicitPrelude #-}
{-# OPTIONS_HADDOCK -show-extensions #-}

module Main where

import GHC.Base
import GHC.List
import System.IO (readFile)
import GVTI (process2)
import System.Environment (getArgs)
import System.Directory
import Data.List (isPrefixOf, lines, unlines)
import Data.Char (isLetter, isDigit) 
import Formatting (formatLines)

main :: IO ()
main = do 
  args00 <- getArgs
  let args = filter (/= "-g") args00
      arg0 = concat . take 1 $ args
      arggs = drop 1 args
      xxs = take 1 . drop 2 . concat . filter ("-c" `isPrefixOf`) $ arggs
      yys = take 2 . drop 2 . concat . filter ("-f" `isPrefixOf`) $ arggs
      bnames = drop 2 . concat . filter ("-b" `isPrefixOf`) $ arggs
      splines = take 1 . drop 2 . concat . filter ("-s" `isPrefixOf`) $ arggs
      remAts = take 1 . drop 1 . concat . filter ("-y" `isPrefixOf`) $ arggs
      gvti = any (== "-g") args00
      delims 
        | any ("-d" `isPrefixOf`) arggs =  drop 2 . concat . filter ("-d" `isPrefixOf`) $ arggs
        | otherwise = ":"
  exI <- doesFileExist arg0
  if exI 
    then do 
      text2 <- readFile arg0 -- well, in the future  this can be extended to also stdin.
      let txt 
           | gvti = unlines  . formatLines (head delims) . filter (any (\x -> isLetter x || isDigit x)) . lines $ text2
           | otherwise =  unlines . filter (any (\x -> isLetter x || isDigit x)) . lines $ text2
      process2 delims xxs yys bnames splines remAts txt
    else error "Main: No file specified exists in the current directory! "