import Graphics.UI.Gtk hiding (eventRegion)
import Graphics.UI.Gtk.Gdk.Events
import Graphics.UI.Gtk.Gdk.GC

import Ray
import Data.Array
import Basics(Color(..))
import Foreign.C.Types
import Foreign.Marshal.Array
import Foreign.Marshal.Alloc
import Foreign(Ptr)
import Data.Word
import Vectors
import Data.IORef
import Bitmaps
import System.IO.Unsafe
import Scenes
import Data.Array.MArray
import Data.Array.Base ( unsafeWrite ) 

main = do
  timeRef <- newIORef (0 :: Scal) 
  initGUI
  putStrLn "GTK inited"
  print $ sum $ elems $ skyBitmap
  dia <- dialogNew
  dialogAddButton dia stockOk ResponseOk
  contain <- dialogGetUpper dia
  canvas <- drawingAreaNew
  canvas `onSizeRequest` return (Requisition 400 200)
  pb <- pixbufNew ColorspaceRgb False 8 400 200
  pbData <- (pixbufGetPixels pb :: IO (PixbufData Int Word8))
  row <- pixbufGetRowstride pb
  chan <- pixbufGetNChannels pb
  bits <- pixbufGetBitsPerSample pb
  putStrLn ("bytes per row: "++show row++", channels per pixel: "++show chan++
	    ", bits per sample: "++show bits)

  let updateFrame = do
        time <- updateTime timeRef
        putStrLn $ "updateCanvas @" ++ show time
        let frame = Ray.rt time
        sequence_ [unsafeWrite pbData (0+x*chan+y*row) (mkCol $ colR $ frame!(y,x)) >>
	           unsafeWrite pbData (1+x*chan+y*row) (mkCol $ colG $ frame!(y,x)) >>
	           unsafeWrite pbData (2+x*chan+y*row) (mkCol $ colB $ frame!(y,x))
	           | x <- [0..399], y <- [0..199] ]
        widgetQueueDraw canvas       
        return True
  canvas `widgetCreateLayout` "Hello World."
  idleAdd updateFrame priorityLow
  canvas `onExpose` updateCanvas canvas pb
  boxPackStartDefaults contain canvas
  widgetShow canvas
  dialogRun dia
  return ()

  


updateCanvas :: DrawingArea -> Pixbuf -> Event -> IO Bool
updateCanvas canvas pb Expose { eventRegion = region } = do
  win <- widgetGetDrawWindow canvas
  gc <- gcNew win
  (width,height) <- widgetGetSize canvas
  rects <- regionGetRectangles region
  (flip mapM_) rects $ \(Rectangle x y w h) -> do
    drawPixbuf win gc pb x y x y (-1) (-1) RgbDitherNone 0 0
  return True



updateTime :: IORef(Scal) ->  IO (Scal)
updateTime timeRef =
    do t <- readIORef timeRef
       writeIORef timeRef (t + 0.2)
       return t




mkCol x = clamp $ round $ (255 * x)
    where clamp x | x < 0 = 0
 	          | x > 255 = 255
 	          | otherwise = x