module Application.HXournal.Coroutine.Page where

import Application.HXournal.Type.Event
import Application.HXournal.Type.Coroutine
import Application.HXournal.Type.Canvas
import Application.HXournal.Type.XournalState
import Application.HXournal.Draw
import Application.HXournal.Accessor
import Application.HXournal.Coroutine.Draw
import Application.HXournal.ModelAction.Adjustment
import Graphics.Xournal.Render.Type 
import Data.Xournal.Generic
import Data.Xournal.Map
import Graphics.UI.Gtk hiding (get,set)
import Application.HXournal.ModelAction.Page
import qualified Control.Monad.State as St 
import Control.Monad.Trans
import Control.Category
import Data.Label
import Prelude hiding ((.), id)
import Data.Xournal.Simple
import qualified Data.IntMap as IM

changePage :: (Int -> Int) -> Iteratee MyEvent XournalStateIO () 
changePage modifyfn = do 
    xstate <- getSt 
    let currCvsId = get currentCanvas xstate
        currCvsInfo = getCanvasInfo currCvsId xstate   
    let xojst = get xournalstate $ xstate 
    case xojst of 
      ViewAppendState xoj -> do 
        let pgs = gpages xoj 
            totalnumofpages = IM.size pgs
            oldpage = get currentPageNum currCvsInfo
            lpage = case IM.lookup (totalnumofpages-1) pgs of
                      Nothing -> error "error in changePage"
                      Just p -> p            
        (xstate',xoj',_pages',_totalnumofpages',newpage) <-
          if (modifyfn oldpage >= totalnumofpages) 
          then do 
            let npage = lpage { glayers = IM.insert 0 (GLayer []) IM.empty } 
                npages = IM.insert totalnumofpages npage pgs 
                newxoj = xoj { gpages = npages } 
                xstate' = set xournalstate (ViewAppendState newxoj) xstate
            putSt xstate'
            return (xstate',newxoj,npages,totalnumofpages+1,totalnumofpages)
          else if modifyfn oldpage < 0 
                 then return (xstate,xoj,pgs,totalnumofpages,0)
                 else return (xstate,xoj,pgs,totalnumofpages,modifyfn oldpage)
        let Dim w h = gdimension lpage
            (hadj,vadj) = get adjustments currCvsInfo
        liftIO $ do 
          adjustmentSetUpper hadj w 
          adjustmentSetUpper vadj h 
          adjustmentSetValue hadj 0
          adjustmentSetValue vadj 0
        let currCvsInfo' = setPage (ViewAppendState xoj') newpage currCvsInfo 
            xstate'' = updatePageAll (ViewAppendState xoj')
                       . updateCanvasInfo currCvsInfo' 
                       $ xstate'
        lift . St.put $ xstate'' 
        invalidate currCvsId 
      SelectState txoj -> do 
        let pgs = gselectAll txoj 
            totalnumofpages = IM.size pgs
            oldpage = get currentPageNum currCvsInfo
            lpage = case IM.lookup (totalnumofpages-1) pgs of
                      Nothing -> error "error in changePage"
                      Just p -> p            
        (xstate',txoj',_pages',_totalnumofpages',newpage) <-
          if (modifyfn oldpage >= totalnumofpages) 
          then do 
            let npage = lpage { glayers = IM.insert 0 (GLayer []) IM.empty } 
                npages = IM.insert totalnumofpages npage pgs 
                newtxoj = txoj { gselectAll = npages } 
                xstate' = set xournalstate (SelectState newtxoj) xstate
            putSt xstate'
            return (xstate',newtxoj,npages,totalnumofpages+1,totalnumofpages)
          else if modifyfn oldpage < 0 
                 then return (xstate,txoj,pgs,totalnumofpages,0)
                 else return (xstate,txoj,pgs,totalnumofpages,modifyfn oldpage)
        let Dim w h = gdimension lpage
            (hadj,vadj) = get adjustments currCvsInfo
        liftIO $ do 
          adjustmentSetUpper hadj w 
          adjustmentSetUpper vadj h 
          adjustmentSetValue hadj 0
          adjustmentSetValue vadj 0
        let currCvsInfo' = setPage (SelectState txoj') newpage currCvsInfo 
            xstate'' = updatePageAll (SelectState txoj')
                       . updateCanvasInfo currCvsInfo' 
                       $ xstate'
        lift . St.put $ xstate'' 
        invalidate currCvsId 
      
canvasZoomUpdate :: Maybe ZoomMode -> CanvasId -> Iteratee MyEvent XournalStateIO ()
canvasZoomUpdate mzmode cid = do 
    xstate <- getSt 
    let cinfoMap = get canvasInfoMap xstate
    case IM.lookup cid cinfoMap of 
      Nothing -> do
        liftIO $ putStrLn $ "canvasZoomUpdate : no cid = " ++ show cid 
        return () 
      Just cvsInfo -> do 
        let zmode = maybe (get (zoomMode.viewInfo) cvsInfo) id mzmode
        let canvas = get drawArea cvsInfo
        let page = getPage cvsInfo 
        let Dim w h = gdimension page
        cpg <- liftIO (getCanvasPageGeometry canvas page (0,0))        
        let (w',h') = canvas_size cpg 
        let (hadj,vadj) = get adjustments cvsInfo 
            s = 1.0 / getRatioFromPageToCanvas cpg zmode
        liftIO $ setAdjustments (hadj,vadj) (w,h) (0,0) (0,0) (w'*s,h'*s)
        let cvsInfo' = set (zoomMode.viewInfo) zmode
                       . set (viewPortOrigin.viewInfo) (0,0)
                       $ cvsInfo 
            xstate' = updateCanvasInfo cvsInfo' xstate
        putSt xstate' 
        invalidate cid       


pageZoomChange :: ZoomMode -> Iteratee MyEvent XournalStateIO () 
pageZoomChange zmode = do 
    xstate <- getSt 
    let currCvsId = get currentCanvas xstate
    canvasZoomUpdate (Just zmode) currCvsId