module Main where

import Graphics.SceneGraph
import Graphics.SceneGraph.Reactive

import Control.Concurrent.MVar
import Control.Monad.State
import Control.Applicative hiding ( (<*>) )
import Control.Concurrent (yield, forkIO, killThread, threadDelay, ThreadId,forkOS)

import Data.Reactive
import Data.IORef
import Data.Monoid

import Calc

calc = runSceneReactive calculator sceneButtonReactive

--
-- To get at the string to display we fmap register to the calculator
--
sceneButtonReactive :: SGM (Event Action)
sceneButtonReactive = do
        snk <- getNodeByLabel "txt" >>= mkText
        ce <- calcEvent
        return $ snk <$> (fmap register ce )
  
-- Build a Calculator event. Build up the button events and 
-- append these events together.
calcEvent :: SGM (Event Calculator)
calcEvent = do 
        btnList <- mapM mkCalcBtn ["0","1","2","3","4","5","6","7","8","9","c", "+","=" ]
        return $ scanlE applyCalc newCalculator $ foldr mappend mempty btnList 


-- Turn passive button in the scene graph into an active one that 
-- provides an event that returns 'lbl'   
mkCalcBtn :: [Char] -> SGM (Event String)   
mkCalcBtn lbl = do
          ev <- getNodeByLabel ("btn" ++ lbl) >>= mkButton
          return $ fmap (const lbl) ev