module Graphics.ChalkBoard.Main 
	( ChalkBoard
	, drawChalkBoard
	, writeChalkBoard
	, updateChalkBoard
	, drawRawChalkBoard
	, exitChalkBoard
	, startChalkBoard
	, openChalkBoard
	, chalkBoardServer
	) where

import System.Process
import System.Environment
import System.IO
import System.Exit
import Control.Concurrent 

import Graphics.ChalkBoard.Core
import Graphics.ChalkBoard.Types
import Graphics.ChalkBoard.Board
import Graphics.ChalkBoard.CBIR
import Graphics.ChalkBoard.CBIR.Compiler
import Graphics.ChalkBoard.OpenGL.CBBE
import Graphics.ChalkBoard.O
import Graphics.ChalkBoard.Options
import Codec.Image.DevIL

import Data.Word
import Control.Concurrent.MVar
import Control.Concurrent
import System.Cmd
import Data.Binary as Bin

import qualified Data.ByteString.Lazy as B
	
	
data ChalkBoardCommand
	= DrawChalkBoard (Board RGB)
	| UpdateChalkBoard (Board RGB -> Board RGB)
	| WriteChalkBoard FilePath
	| ExitChalkBoard
	| DrawRawChalkBoard [Inst BufferId]
	
data ChalkBoard = ChalkBoard (MVar ChalkBoardCommand) (MVar ())


-- | Draw a board onto the ChalkBoard.
drawChalkBoard :: ChalkBoard -> Board RGB -> IO ()
drawChalkBoard (ChalkBoard var _) brd = putMVar var (DrawChalkBoard brd)

-- | Write the contents of a ChalkBoard into a File.
writeChalkBoard :: ChalkBoard -> FilePath -> IO ()
writeChalkBoard (ChalkBoard var _) nm = putMVar var (WriteChalkBoard nm)


-- | modify the current ChalkBoard.
updateChalkBoard :: ChalkBoard -> (Board RGB -> Board RGB) -> IO ()
updateChalkBoard (ChalkBoard var _) brd = putMVar var (UpdateChalkBoard brd)

-- | Debugging hook for writing raw CBIR code.
drawRawChalkBoard :: ChalkBoard -> [Inst BufferId] -> IO ()
drawRawChalkBoard (ChalkBoard var _) cmds = putMVar var (DrawRawChalkBoard cmds)

-- | pause for this many seconds, since the last redraw *started*.
pauseChalkBoard :: ChalkBoard -> Double -> IO ()
pauseChalkBoard _ n = do
	threadDelay (fromInteger (floor (n * 1000000)))
	
-- | quit ChalkBoard.
exitChalkBoard :: ChalkBoard -> IO ()
exitChalkBoard (ChalkBoard var end) = do
	putMVar var ExitChalkBoard
	takeMVar end 
	return ()

-- | Start, in this process, a ChalkBoard window, and run some commands on it.
startChalkBoard :: [Options] -> (ChalkBoard -> IO ()) -> IO ()
startChalkBoard options cont = do
	putStrLn  "[Starting ChalkBoard]"
	ilInit

	v0 <- newEmptyMVar
	v1 <- newEmptyMVar 
	v2 <- newEmptyMVar 
	vEnd <- newEmptyMVar
	
	forkIO $ compiler options v1 v2 
	forkIO $ do
		() <- takeMVar v0
		cont (ChalkBoard v1 vEnd)
		print "[Done]"
	startRendering viewBoard v0 v2 options
	return ()	

-- | Open, remotely, a ChalkBoard windown, and return a handle to it.
-- Needs "CHALKBOARD_SERVER" set to the location of the ChalkBoard server.
openChalkBoard :: [Options] -> IO ChalkBoard
openChalkBoard args = do
	putStrLn "[Opening Channel to ChalkBoard Server]"
	ilInit

	v0 <- newEmptyMVar
	v1 <- newEmptyMVar 
	v2 <- newEmptyMVar 
	vEnd <- newEmptyMVar

	(ein,eout,err,pid) <- openServerStream		
	
	let options = encode (args :: [Options])
	B.hPut ein (encode (fromIntegral (B.length options) :: Word32))
	B.hPut ein options
	hFlush ein

	forkIO $ compiler args v1 v2
	forkIO $ do
		let loop n = do
			v <- takeMVar v2
			let code = encode v
			B.hPut ein (encode (fromIntegral (B.length code) :: Word32))
			B.hPut ein code
			hFlush ein
			case v of
			  [Exit] -> putMVar vEnd ()
			  _ -> loop $! (n+1)
		loop 0

	return (ChalkBoard v1 vEnd)

viewBoard :: Int
viewBoard = 0

compiler :: [Options] -> MVar ChalkBoardCommand -> MVar [Inst Int] -> IO ()
compiler options v1 v2 = do
	putMVar v2 [Allocate viewBoard (x,y) RGB24Depth (BackgroundRGB24Depth (RGB 1 1 1))]
	loop (0::Integer) (boardOf (o (RGB 1 1 1)))
  where     
     (x,y) = head ([ (x,y) | BoardSize x y <- options ] ++ [(400,400)])
     loop n old_brd = do
	cmd <- takeMVar v1
	case cmd of
	  DrawChalkBoard brd -> do
		cmds <- compile (x,y) viewBoard (move (0.5,0.5) brd)
--		putStrLn $ showCBIRs cmds
		putMVar v2 cmds
		loop (n+1) brd
	  UpdateChalkBoard fn -> do
		let brd = fn old_brd
		cmds <- compile (x,y) viewBoard (move (0.5,0.5) brd)
--		putStrLn $ showCBIRs cmds
		putMVar v2 cmds
		loop (n+1) brd
	  DrawRawChalkBoard cmds -> do
		putMVar v2 cmds
		loop (n+1) (error "Board in an unknown state")
	  WriteChalkBoard filename -> do
		putMVar v2 [SaveImage viewBoard filename]
		loop (n+1) old_brd

	  ExitChalkBoard -> putMVar v2 [Exit]


openServerStream :: IO (Handle,Handle,Handle,ProcessHandle)
openServerStream = do
	server <- getEnv "CHALKBOARD_SERVER" `catch` (\ _ -> return "chalkboard-server-1_9_0_14")
	runInteractiveProcess server [] Nothing Nothing `catch` (\ _ -> do print "DOOL" ; error "")


-- | create an instance of the ChalkBoard. Only used by the server binary.
chalkBoardServer :: IO ()
chalkBoardServer = do
	v0 <- newEmptyMVar
	v2 <- newEmptyMVar 
	bs <- B.hGet stdin 4
	let n :: Word32
	    n = Bin.decode bs
	options <- B.hGet stdin (fromIntegral n)
	forkIO $ do
		let loop = do
			bs <- B.hGet stdin 4
			let n :: Word32
			    n = Bin.decode bs
			packet <- B.hGet stdin (fromIntegral n)
			putMVar v2 (decode packet :: [Inst BufferId])
			loop
		loop
	startRendering viewBoard v0 v2 (decode options :: [Options])
	return ()