{-# LANGUAGE StandaloneDeriving #-}
import FRP.Netwire hiding (when)
import Prelude hiding ((.), id, null, filter)
import Data.Time.Clock
import Control.Wire hiding (when)
import Control.Wire.Session
import Control.Monad
import qualified Graphics.UI.SDL as SDL
import AlsaSeq
import qualified Data.Set as Set

netwireIsCool :: (Monad m) => Wire (Timed NominalDiffTime ()) () m a String
netwireIsCool =
    for 2.5 . pure "Once upon a time..." -->
    for 3   . pure "... games were completely imperative..." -->
    for 2   . pure "... but then..." -->
    for 10  . (pure "Netwire 5! " <> anim) -->
    netwireIsCool

  where
    anim =
        holdFor 0.5 . periodic 1 . pure "Hoo..." <|>
        pure "...ray!"

main =
  withAlsaInit $ \h public private q publicAddr privateAddr -> do
  cmdlineAlsaConnect h public -- fail early if bad command lines

  SDL.withInit [SDL.InitVideo, SDL.InitTimer, SDL.InitJoystick] $ do
  info <- SDL.getVideoInfo
  let width = SDL.videoInfoWidth info
      height = SDL.videoInfoHeight info
--screen <- SDL.setVideoMode width height 32 [SDL.SWSurface, SDL.Fullscreen]
  screen <- SDL.setVideoMode width height 32 [SDL.SWSurface]
  putStrLn "Initialized."

  let parseAlsa keysDown = parseAlsaEvents h keysDown (forwardNoteEvent h q publicAddr)
  let loop midiKeysDown keysDown s w x = do
        keysDown' <- parseSDLEvents keysDown
        midiKeysDown' <- parseAlsa midiKeysDown
        (ds, s') <- stepSession s
        (ex, w') <- stepWire w ds (Right x)
        let x' = either (const "") id ex
        Control.Monad.when (x /= x' && x' /= "") $ putStrLn x'
        let framerate = 30
        let delay = 1000 `div` framerate - 1000 * (floor $ dtime ds)
        SDL.delay (delay)
        Control.Monad.when (not $ keyDown SDL.SDLK_ESCAPE keysDown) $
          loop midiKeysDown' keysDown' s' w' x'

  loop Set.empty Set.empty clockSession_ netwireIsCool ""

parseSDLEvents :: Set.Set SDL.Keysym -> IO (Set.Set SDL.Keysym)
parseSDLEvents keysDown = do
  event <- SDL.pollEvent
  case event of
    SDL.NoEvent -> return keysDown
    SDL.KeyDown k -> parseSDLEvents (Set.insert k keysDown)
    SDL.KeyUp k -> parseSDLEvents (Set.delete k keysDown)
    _ -> parseSDLEvents keysDown

keyDown :: SDL.SDLKey -> Set.Set SDL.Keysym -> Bool
keyDown k = not . Set.null . Set.filter ((== k) . SDL.symKey)

deriving instance Ord SDL.Keysym