{-# LANGUAGE LambdaCase       #-}
{-# LANGUAGE OverloadedLabels #-}
module MeshMaker where

import Control.Monad
import Data.Coerce
import Data.IORef
import Foreign.C.Types
import GI.Gdk
import GI.GObject.Functions
import GI.Gtk

data MeshMaker = MeshMaker
    { mmWidget   :: GLArea
    , mmRealized :: IORef (Maybe State)
    }

data State = State
    {
    }

new :: IO GLArea
new = do
    w <- gLAreaNew
    ref <- newIORef Nothing
    let st = MeshMaker w ref
    -- _ <- on w #createContext $ onCreateContext st
    _ <- on w #realize   $ onRealize st
    _ <- on w #unrealize $ onUnrealize st
    return w

onRealize :: MeshMaker -> IO ()
onRealize mm@(MeshMaker w ref) = do
    readIORef ref >>= \case
        Just st -> onUnrealize mm -- Shouldn't happen.
        Nothing -> return ()
    writeIORef ref $ Just State
        {
        }

onUnrealize :: MeshMaker -> IO ()
onUnrealize (MeshMaker w ref) = do
    readIORef ref >>= \case
        Just st -> do
            return ()
        Nothing -> return () -- Shouldn't happen.
    writeIORef ref Nothing


onRender :: MeshMaker -> GLContext -> IO Bool
onRender (MeshMaker w ref) gl = do
    return True

onScroll :: MeshMaker -> EventScroll -> IO Bool
onScroll (MeshMaker w ref) ev = do
    dx <- get ev #deltaX
    dy <- get ev #deltaY
    x <- get ev #x
    y <- get ev #y
    y_root <- get ev #yRoot
    d <- get ev #direction
    -- onScroll! ((0.0,0.0),(11.057525634765625,5.210357666015625),79.21035766601563)
    putStrLn $ "onScroll! " ++ show (d,(dx,dy),(x,y),y_root)
    return True

onTouch :: MeshMaker -> Event -> IO Bool
onTouch (MeshMaker w ref) ev = do
    putStrLn $ "onTouch!"
    return True

onMotion :: MeshMaker -> EventMotion -> IO Bool
onMotion (MeshMaker w ref) ev = do
    return True