module Graphics.Gloss.Export.Gif
    ( exportPicturesToGif
    , GifDelay(..)
    , GifLooping(..)
    ) where

--import Codec.Picture.Types
import Codec.Picture 
import qualified Graphics.Gloss.Rendering as Gloss
import Control.Monad (forM_, mapAndUnzipM)
import Foreign.Marshal.Alloc (free)

import Graphics.Gloss.Export.Image

-- | Save a gloss animation as PNG
exportPicturesToGif :: GifDelay    -- ^ time between frames in centiseconds
                    -> GifLooping
                    -> Size        -- ^ width, height in pixels as in Gloss.Display
                    -> Gloss.Color -- ^ background color
                    -> FilePath
                    -> Animation   -- ^ function that maps from point in time to Picture. analog to Gloss.Animation
                    -> [Float]     -- ^ list of points in time at which to evaluate the animation
                    -> IO ()
exportPicturesToGif gifDelay gifLooping size bgc f anim ts = do
  s <- initialize size
  (imgs, ptrs) <- mapAndUnzipM (pictureToImageRGB8 size bgc s) (map anim ts)
  case writeGifAnimation f gifDelay gifLooping imgs of
    Left errmsg -> putStrLn ("Error:" ++ errmsg)
    Right io -> io
  forM_ ptrs free

{- slower on my machine -> not distributed
   but maybe helpful in the future e.g. when juicy-pixels offers `writeGifAnimation` with RGBA8
exportPicturesToGifByConverting :: GifDelay    -- ^ time between frames (Int)
                    -> GifLooping
                    -> Size        -- ^ width, height in pixels 
                    -> Gloss.Color -- ^ background color
                    -> FilePath
                    -> Animation   -- ^ function that maps from point in time to Picture. analog to Gloss.Animation
                    -> [Float]     -- ^ list of points in time at which to evaluate the animation
                    -> IO ()
exportPicturesToGifByConverting gifDelay gifLooping size bgc f anim ts = do
  s <- initialize size
  (imgs, ptrs) <- mapAndUnzipM (pictureToImageRGBA8 size bgc s) (map anim ts)
  let imgs' = map (convertRGB8 . ImageRGBA8) imgs
  case writeGifAnimation f gifDelay gifLooping imgs' of
    Left errmsg -> putStrLn ("Error:" ++ errmsg)
    Right io -> io
  forM_ ptrs $ \ptr -> do
    free ptr
-}

{- RGB8
real	0m2,229s
user	0m4,030s
sys	0m1,874s

RGBA8 then conversion
real	0m3,438s
user	0m6,987s
sys	0m2,649s

-}