module Main where

import Types
import PPM
import Functions

import System.IO
import System.Environment
import Data.Maybe

pic0, pic1 :: Picture

pic0	= readPicture "P1\n1 1\n0"
pic1	= readPicture "P1\n2 2\n0 1 1 0"
pic2	= readPicture $
	  "P2\n" ++
	  "4 5 255\n" ++
	  "0 63 127 191 255\n" ++
	  "0 10 20 30 40\n" ++
	  "100 100 100 100 100\n" ++
	  "4 3 2 1 0\n"

pic2'	= (showPNM . pictureToPGM) pic2


-- --------------------------------------
--
-- basic file input output

getFileContent		:: String -> IO String
getFileContent f
    | f == ""
      ||
      f == "-"		= getContents
    | f == "0"		= return "P1\n1 1\n0"
    | otherwise		= readFile f

openOutputFile		:: String -> IO Handle
openOutputFile f
    | f == ""
      ||
      f == "-"		= return stdout
    | otherwise		= openFile f WriteMode

-- --------------------------------------

changePicture	:: (Picture -> Picture) ->
		   String -> String -> IO()
changePicture fct inp outp
    = do
      p <- getFileContent inp
      f <- openOutputFile outp
      hPutStr f (processPicture p)
      hClose f
    where
    processPicture
	= showPNM . pictureToPGM . fct . readPicture

-- --------------------------------------

getParams	:: IO [String]
getParams
    = do
      args <- getArgs
      return (args ++ repeat "")

main	:: IO()
main
    = do
      args <-getParams
      main1 args

main1	:: [String] -> IO()
main1 (opr : inp : outp : _)
    = do
      changePicture (lookupOp opr) inp outp
    where
    lookupOp op
	= (fromMaybe id . lookup op) fctTab

    fctTab	:: [(String, Picture -> Picture)]
    fctTab
	= [ ("id"       , id            )
	  , ("bitmap"	, bitMap	)
	  , ("fliph"	, flipH		)
	  , ("flipv"	, flipV		)
	  , ("gamma.5"	, gamma 0.5	)
	  , ("gamma2"	, gamma 2.0	)
	  , ("halfsize"	, halfSize	)
	  , ("invert"	, invert	)
	    -- map (map (\ x -> 1.0 - x)))
	  , ("id"	, id		)
	  , ("reduce3"	, reduceColors 3	)
	  , ("rot90"	, rot90		)
	  , ("rot180"	, rot180	)
	  , ("rot270"	, rot270	)
	  , ("stretch"	, stretch	)
	  ]

-- --------------------------------------