{-# OPTIONS_HADDOCK hide #-}

module System.Console.ANSI.Unix
  (
-- This file contains code that is common to modules
-- System.Console.ANSI.Unix and System.Console.ANSI.Windows, namely the module
-- exports and the associated Haddock documentation.
#include "Exports-Include.hs"
  ) where

import Control.Exception.Base (bracket)
import System.IO (BufferMode (..), Handle, hFlush, hGetBuffering, hGetEcho,
  hIsTerminalDevice, hPutStr, hSetBuffering, hSetEcho, stdin, stdout)
import Text.ParserCombinators.ReadP (readP_to_S)

import System.Console.ANSI.Codes
import System.Console.ANSI.Types

-- This file contains code that is common to modules System.Console.ANSI.Unix,
-- System.Console.ANSI.Windows and System.Console.ANSI.Windows.Emulator, such as
-- type signatures and the definition of functions specific to stdout in terms
-- of the corresponding more general functions, inclduding the related Haddock
-- documentation.
#include "Common-Include.hs"
-- This file contains code that is common save that different code is required
-- in the case of the module System.Console.ANSI.Windows.Emulator (see the file
-- Common-Include-Emulator.hs in respect of the latter).
#include "Common-Include-Enabled.hs"

hCursorUp h n = hPutStr h $ cursorUpCode n
hCursorDown h n = hPutStr h $ cursorDownCode n
hCursorForward h n = hPutStr h $ cursorForwardCode n
hCursorBackward h n = hPutStr h $ cursorBackwardCode n

hCursorDownLine h n = hPutStr h $ cursorDownLineCode n
hCursorUpLine h n = hPutStr h $ cursorUpLineCode n

hSetCursorColumn h n = hPutStr h $ setCursorColumnCode n
hSetCursorPosition h n m = hPutStr h $ setCursorPositionCode n m

hSaveCursor h = hPutStr h saveCursorCode
hRestoreCursor h = hPutStr h restoreCursorCode
hReportCursorPosition h = hPutStr h reportCursorPositionCode

hClearFromCursorToScreenEnd h = hPutStr h clearFromCursorToScreenEndCode
hClearFromCursorToScreenBeginning h
    = hPutStr h clearFromCursorToScreenBeginningCode
hClearScreen h = hPutStr h clearScreenCode

hClearFromCursorToLineEnd h = hPutStr h clearFromCursorToLineEndCode
hClearFromCursorToLineBeginning h = hPutStr h clearFromCursorToLineBeginningCode
hClearLine h = hPutStr h clearLineCode

hScrollPageUp h n = hPutStr h $ scrollPageUpCode n
hScrollPageDown h n = hPutStr h $ scrollPageDownCode n

hSetSGR h sgrs = hPutStr h $ setSGRCode sgrs

hHideCursor h = hPutStr h hideCursorCode
hShowCursor h = hPutStr h showCursorCode

hSetTitle h title = hPutStr h $ setTitleCode title

-- getReportedCursorPosition :: IO String
-- (See Common-Include.hs for Haddock documentation)
getReportedCursorPosition = bracket (hGetEcho stdin) (hSetEcho stdin) $ \_ -> do
  hSetEcho stdin False   -- Turn echo off
  get
 where
  get = do
    c <- getChar
    if c == '\ESC'
      then get' [c]
      else return [c] -- If the first character is not the expected \ESC then
                      -- give up. This provides a modicom of protection against
                      -- unexpected data in the input stream.
  get' s = do
    c <- getChar
    if c /= 'R'
      then get' (c:s) -- Continue building the list, until the expected 'R'
                      -- character is obtained. Build the list in reverse order,
                      -- in order to avoid O(n^2) complexity.
      else return $ reverse (c:s) -- Reverse the order of the built list.

-- getCursorPosition :: IO (Maybe (Int, Int))
-- (See Common-Include.hs for Haddock documentation)
getCursorPosition = do
  input <- bracket (hGetBuffering stdin) (hSetBuffering stdin) $ \_ -> do
    hSetBuffering stdin NoBuffering -- set no buffering (the contents of the
                                    -- buffer will be discarded, so this needs
                                    -- to be done before the cursor positon is
                                    -- emitted)
    reportCursorPosition
    hFlush stdout -- ensure the report cursor position code is sent to the
                  -- operating system
    getReportedCursorPosition
  case readP_to_S cursorPosition input of
    [] -> return Nothing
    [((row, col),_)] -> return $ Just (row, col)
    (_:_) -> return Nothing