module Main where

import           Data.Maybe
import           ImageTypes
import           ReadImage
import           ShowImage
import           System.Environment
import           System.IO

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

processImage :: FilePath -> FilePath
             -> (Image -> Image)
             -> IO ()
processImage src dst f
    = do ih <- openBinaryFile src ReadMode
         c  <- hGetContents ih
         let res = showImage True . f . readImage $ c
         oh <- openBinaryFile dst WriteMode
         hPutStr oh res
         hClose ih
         hClose oh

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

main    :: IO()
main
    = getArgs >>= main1

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

    fctTab      :: [(String, Image -> Image)]
    fctTab
        = [ ("id"       , id            )
          , ("bitmap"   , bitmap        )
          , ("fliph"    , flipH         )
          , ("flipv"    , flipV         )
          , ("gamma.5"  , gamma 0.5     )
          , ("gamma2"   , gamma 2.0     )
          , ("halfsize" , halfSize      )
          , ("invert"   , invert        )
          , ("reduce3"  , reduceColors 3        )
          , ("rot90"    , rot90         )
          , ("rot180"   , rot180        )
          , ("rot270"   , rot270        )
          , ("double"   , scale 2 3     )
          , ("tile4"    , tile 2 2      )
          , ("tilemir4" , tileMirr 2 2  )
          , ("shiftrot" , shiftRot 20 20)
          , ("mult"      , \ i -> merge2 (*) i (flipV i))
          ]
main1 args
    = hPutStrLn stderr $ "usage: Uebung7 <fct> <input> <output> (got: " ++ show args ++ ")"

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