module VisualBrowseTree where

import Control.Concurrent
import Control.Concurrent.STM
import Control.Monad

import Data.Maybe
import Data.Tree
import Data.Tree.Zipper
import qualified Data.Foldable as Foldable
import qualified Data.Traversable as T

import Graphics.UI.Gtk
import Graphics.UI.Gtk.WebKit.Download
import Graphics.UI.Gtk.WebKit.NetworkRequest
import Graphics.UI.Gtk.WebKit.WebFrame
import Graphics.UI.Gtk.WebKit.WebNavigationAction
import Graphics.UI.Gtk.WebKit.WebSettings
import Graphics.UI.Gtk.WebKit.WebView
import Graphics.UI.Gtk.WebKit.WebWindowFeatures

import System.Exit
import System.Process
import Text.Printf

import Utils
import NotebookSimple
import Datatypes
import Commands


browseTreeToSVG :: [Tree Page] -> IO String
browseTreeToSVG btree = do
  let ellipsis t n | length t < n = t
                   | otherwise = take n t ++ "..."

  nodeID <- newTVarIO (0::Int)
  btree' <- mapM (T.mapM (\p -> do
            i <- atomically $ do
                   iden <- readTVar nodeID
                   writeTVar nodeID (iden+1)
                   return iden
            t <- getPageTitle p
            return (i,(t,mkStablePageLink p)))) btree

  let prelude = unlines ["digraph \"Browse tree\" {",
                         "graph [",
                         "fontname = \"Helvetica-Oblique\",",
                         "page = 10",
                         "size = 30",
                         " ];"]
      -- labels = unlines [ printf "d%d [label=\"%s\"];" i t | (i,t) <- concatMap flatten btree' ]
      footer = "}"

      btreeZip = concatMap flattenToZipper' btree' -- ellipsis t 15
      labels = unlines [ printf "d%d [URL=\"%s\", shape=polygon, fixedsize=true, fontsize=8, width=1.25, height=0.25, tooltip=\"%s\", label=\"%s\"];"
                                i link t (ellipsis t 10) | (i,(t,link)) <- map label btreeZip ]
      edges = unlines [ printf "d%d -> d%d;" (fst . label . fromJust . parent $ z ) (fst . label $ z)
                            | z <- btreeZip,
                              parent z /= Nothing]

      edges2 =  [ ((fst . label . fromJust . parent $ z ),(fst . label $ z))
                      | z <- btreeZip,
                             parent z /= Nothing]


      everything = prelude ++ edges ++ labels ++ footer

  print everything
  print edges2
  tot@(code,svg,dotErr) <- readProcessWithExitCode "dot" ["-Tsvg"] everything
 -- _ <- readProcessWithExitCode "dot" ["-Tsvg","-ograph.svg"] everything
 -- _ <- readProcessWithExitCode "dot" ["-ograph.dot"] everything
  print tot
  case code of
    ExitSuccess -> return svg
    ExitFailure c -> return $ printf "<text>Error running 'dot' command. Exit code: %s\n%s</text>" (show c) dotErr

-- mkStablePageLink page = let (GObject foreignPtr) = toGObject (pgWidget page) in PageLink foreignPtr

lookupStablePageLink :: [Tree Page] -> PageLink -> Maybe Page
lookupStablePageLink pages link = listToMaybe $ catMaybes (map (Foldable.find (\p -> mkStablePageLink p == link)) pages)
mkStablePageLink page = "page://" ++ (show $ pgIdent page)

mkLinks :: [Page] -> [PageLink]
mkLinks = map mkStablePageLink

-- visualBrowseTreeWidget :: t -> IO Widget
visualBrowseTreeWidget :: (Page -> IO ()) -> TVar [Tree Page] -> IO Widget
visualBrowseTreeWidget viewPage btreeVar = do
  -- webkit widget
  web <- webViewNew
  webViewSetTransparent web True
  webViewSetFullContentZoom web True

  -- scrolled window to enclose the webkit
  scrollWeb <- scrolledWindowNew Nothing Nothing
  containerAdd scrollWeb web

  settings <- webViewGetWebSettings web
  set settings [webSettingsEnablePlugins := False]

  let refreshSVG = do
        svg <- browseTreeToSVG =<< readTVarIO btreeVar
        webViewLoadString web svg (Just "image/svg+xml") Nothing ""

  on web navigationPolicyDecisionRequested $ \ webframe networkReq webNavAct webPolDec -> do
    print "[navigationPolicyDecisionRequested]"
    muri <- networkRequestGetUri networkReq
    case muri of
      Nothing -> return ()
      Just uri -> do
                print ("visualBrowseTreeWidget",uri)
                t <- readTVarIO btreeVar
                case lookupStablePageLink t uri of
                  Nothing -> print ("Page no longer exist: " ++ show uri)
--                  Just p -> viewPage p
                  Just p -> sendCommand (ViewPageCommand (pgIdent p)) -- viewPage p

    return True

  -- watch btreeVar for changes, update
  let watchdog page = do
          page' <- waitTVarChangeFrom page btreeVar
          postGUIAsync refreshSVG
          watchdog page'
  forkIO (watchdog =<< readTVarIO btreeVar)
  forkIO (forever $ do
            threadDelay (10^6)
            postGUIAsync refreshSVG)

  refreshSVG
  return (toWidget scrollWeb)

visualBrowseTreeWindow viewPage btreeVar = do
  window <- windowNew
  visualBT <- visualBrowseTreeWidget viewPage btreeVar
  set window [ containerBorderWidth := 10,
              windowTitle := "Spike browser - visual browse tree",
              containerChild := visualBT,
              windowAllowGrow := True ]
  widgetShowAll window

  return window