{-# OPTIONS_GHC -Wno-unused-imports #-}

module Util where


import qualified Data.Char                     as Char
import           Data.Text                      ( Text )
import qualified Data.Text                     as Text
import qualified System.Console.ANSI           as Ansi
import           System.Exit                    ( ExitCode
                                                  ( ExitFailure
                                                  , ExitSuccess
                                                  )
                                                )


t :: String -> Text
t = Text.pack

fGrey :: Text
fGrey =
  t $ Ansi.setSGRCode [Ansi.SetColor Ansi.Foreground Ansi.Dull Ansi.White]
fWhite :: Text
fWhite =
  t $ Ansi.setSGRCode [Ansi.SetColor Ansi.Foreground Ansi.Vivid Ansi.White]
fWhiteDis :: Text
fWhiteDis = t ""
fRedDis :: Text
fRedDis = t "" -- TODO disabled until the bug is fixed.
 -- setFGColorDull Ansi.Red

fReset :: Text
fReset = t $ Ansi.setSGRCode [Ansi.Reset]

setFGColorVivid :: Ansi.Color -> Text
setFGColorVivid c =
  t $ Ansi.setSGRCode [Ansi.SetColor Ansi.Foreground Ansi.Vivid c]
setFGColorDull :: Ansi.Color -> Text
setFGColorDull c =
  t $ Ansi.setSGRCode [Ansi.SetColor Ansi.Foreground Ansi.Dull c]

showEC :: ExitCode -> Text
showEC = \case
  ExitSuccess   -> setFGColorVivid Ansi.Green <> t "0" <> fReset
  ExitFailure i -> setFGColorVivid Ansi.Red <> t (show i) <> fReset

filterEscapeFunc :: Text -> Text
filterEscapeFunc input = go Text.empty input
 where
  isSpecial c = Char.isControl c
  go clean open = case Text.break isSpecial open of
    (a, b) -> case Text.uncons b of
      Nothing             -> clean <> a
      Just ('\x07', rest) -> go (clean <> a) rest -- bell
      Just ('\x08', rest) -> if Text.null a -- backspace
        then if Text.null clean
          then go clean rest
          else go (Text.init clean) rest
        else go (clean <> Text.init a) rest
      Just ('\x09', rest) -> -- tab
        go (clean <> a <> Text.pack "  ") rest
      Just ('\x1b', rest) ->  -- esc
                             clean <> a <> case Text.uncons rest of
        Nothing             -> Text.empty
        Just ('\x5b', more) -> finishEscape more
        Just ('\x9b', more) -> finishEscape more
        Just (_     , more) -> filterEscapeFunc more
      Just (_, rest) -> go (clean <> a) rest
  finishEscape remain = case Text.uncons remain of
    Nothing        -> remain
    Just (c, rest) -> if c >= '\x40' && c <= '\x7e'
      then filterEscapeFunc rest
      else finishEscape rest