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.Type 
import Graphics.Xournal.Type.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 Text.Xournal.Type
import Graphics.Xournal.Type.Select
import qualified Data.IntMap as IM

changePage :: (Int -> Int) -> Iteratee MyEvent XournalStateIO () 
changePage modifyfn = do 
    xstate <- getSt 
    let currCvsId = get currentCanvas xstate
        -- cinfoMap = get canvasInfoMap xstate
        currCvsInfo = getCanvasInfo currCvsId xstate   
    let xojst = get xournalstate $ xstate 
    case xojst of 
      ViewAppendState xoj -> do 
        let pgs = xbm_pages 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 = mkPageBBoxMapFromPageBBox 
                        . mkPageBBoxFromPage
                        . newPageFromOld 
                        . pageFromPageBBoxMap $ lpage
                npages = IM.insert totalnumofpages npage pgs 
                newxoj = xoj { xbm_pages = 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 = pageDim 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 = tx_pages 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 = mkPageBBoxMapFromPageBBox 
                        . mkPageBBoxFromPage
                        . newPageFromOld 
                        . pageFromPageBBoxMap $ lpage
                npages = IM.insert totalnumofpages npage pgs 
                newtxoj = txoj { tx_pages = 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 = pageDim 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 
      

pageZoomChange :: ZoomMode -> Iteratee MyEvent XournalStateIO () 
pageZoomChange zmode = do 
    xstate <- getSt 
    let currCvsId = get currentCanvas xstate
        cinfoMap = get canvasInfoMap xstate
        currCvsInfo = case IM.lookup currCvsId cinfoMap of 
                        Nothing -> error " no such cvsinfo in pageZoomChange"  
                        Just cinfo -> cinfo 
    let canvas = get drawArea currCvsInfo
    let page = getPage currCvsInfo 
    let Dim w h = pageDim page
    cpg <- liftIO (getCanvasPageGeometry canvas page (0,0))        
    let (w',h') = canvas_size cpg 
    let (hadj,vadj) = get adjustments currCvsInfo 
        s = 1.0 / getRatioFromPageToCanvas cpg zmode
    liftIO $ setAdjustments (hadj,vadj) (w,h) (0,0) (0,0) (w'*s,h'*s)
    let currCvsInfo' = set (zoomMode.viewInfo) zmode
                       . set (viewPortOrigin.viewInfo) (0,0)
                       $ currCvsInfo 
        xstate' = updateCanvasInfo currCvsInfo' xstate
    putSt xstate' 
    invalidate currCvsId