-----------------------------------------------------------------------------
-- |
-- Module      : Hoodle.Coroutine.Eraser 
-- Copyright   : (c) 2011-2013 Ian-Woo Kim
--
-- License     : BSD3
-- Maintainer  : Ian-Woo Kim <ianwookim@gmail.com>
-- Stability   : experimental
-- Portability : GHC
--
-----------------------------------------------------------------------------

module Hoodle.Coroutine.Eraser where

import Control.Category
-- import Data.Label
import qualified Data.IntMap as IM
import Control.Lens
import Control.Monad.State 
import qualified Control.Monad.State as St
import Graphics.UI.Gtk hiding (get,set,disconnect)
-- 
import Data.Hoodle.Generic
import Data.Hoodle.BBox
import Graphics.Hoodle.Render
import Graphics.Hoodle.Render.Type.Item 
import Graphics.Hoodle.Render.Util.HitTest
-- 
import Hoodle.Type.Event
import Hoodle.Type.Coroutine
import Hoodle.Type.Canvas
import Hoodle.Type.HoodleState
import Hoodle.Type.PageArrangement
import Hoodle.Device
import Hoodle.View.Coordinate
import Hoodle.View.Draw
import Hoodle.Coroutine.EventConnect
import Hoodle.Coroutine.Draw
import Hoodle.Coroutine.Commit
import Hoodle.Accessor
import Hoodle.ModelAction.Page
import Hoodle.ModelAction.Eraser
import Hoodle.ModelAction.Layer
import Hoodle.Coroutine.Pen 
--
import Prelude hiding ((.), id)

-- |
eraserStart :: CanvasId 
               -> PointerCoord 
               -> MainCoroutine () 
eraserStart cid = commonPenStart eraserAction cid  
  where eraserAction _cinfo pnum geometry (cidup,cidmove) (x,y) = do 
          itms <- rItmsInCurrLyr
          eraserProcess cid pnum geometry cidup cidmove itms (x,y)

-- |

eraserProcess :: CanvasId
              -> PageNum 
              -> CanvasGeometry
              -> ConnectId DrawingArea -> ConnectId DrawingArea 
              -> [RItem] -- [StrokeBBox] 
              -> (Double,Double)
              -> MainCoroutine () 
eraserProcess cid pnum geometry connidmove connidup itms (x0,y0) = do 
    r <- nextevent 
    xst <- get
    boxAction (f r xst) . getCanvasInfo cid $ xst 
  where 
    f :: (ViewMode a) => MyEvent -> HoodleState -> CanvasInfo a -> MainCoroutine ()
    f r xstate cvsInfo = penMoveAndUpOnly r pnum geometry defact 
                                 (moveact xstate cvsInfo) upact
    defact = eraserProcess cid pnum geometry connidup connidmove itms (x0,y0)
    upact _ = disconnect [connidmove,connidup] >> invalidateAll
    moveact xstate cvsInfo (_pcoord,(x,y)) = do 
      let line = ((x0,y0),(x,y))
          hittestbbox = hltHittedByLineRough line itms
          (hittestitem,hitState) = 
            St.runState (hltItmsHittedByLineFrmSelected_StateT line hittestbbox) False
      if hitState 
        then do 
          page <- getCurrentPageCvsId cid 
          let currhdl     = unView . view hoodleModeState $ xstate 
              dim         = view gdimension page
              pgnum       = view currentPageNum cvsInfo
              (mcurrlayer, currpage) = getCurrentLayerOrSet page
              currlayer = maybe (error "eraserProcess") id mcurrlayer
          let (newitms,maybebbox1) = St.runState (eraseHitted hittestitem) Nothing
              maybebbox = fmap (flip inflate 2.0) maybebbox1
          newlayerbbox <- liftIO . updateLayerBuf dim maybebbox 
                          . set gitems newitms $ currlayer 
          let newpagebbox = adjustCurrentLayer newlayerbbox currpage 
              newhdlbbox = over gpages (IM.adjust (const newpagebbox) pgnum) currhdl
              newhdlmodst = ViewAppendState newhdlbbox
          commit . set hoodleModeState newhdlmodst 
            =<< (liftIO (updatePageAll newhdlmodst xstate))
          invalidateInBBox Nothing Efficient cid 
          nitms <- rItmsInCurrLyr
          eraserProcess cid pnum geometry connidup connidmove nitms (x,y)
        else eraserProcess cid pnum geometry connidmove connidup itms (x,y)