{--
HSFM, a filemanager written in Haskell.
Copyright (C) 2016 Julian Ospald

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
--}

{-# LANGUAGE OverloadedStrings #-}
{-# OPTIONS_HADDOCK ignore-exports #-}

module HSFM.GUI.Gtk.Callbacks where


import Control.Concurrent.STM
  (
    readTVarIO
  )
import Control.Exception
  (
    throw
  )
import Control.Monad
  (
    forM_
  , void
  , when
  )
import Control.Monad.IO.Class
  (
    liftIO
  )
import Data.Foldable
  (
    for_
  )
import Graphics.UI.Gtk
import qualified HPath as P
import HPath
    (
      Abs
    , Path
    )
import HSFM.FileSystem.Errors
import HSFM.FileSystem.FileOperations
import HSFM.FileSystem.FileType
import HSFM.GUI.Gtk.Data
import HSFM.GUI.Gtk.Dialogs
import HSFM.GUI.Gtk.MyView
import HSFM.GUI.Gtk.Utils
import HSFM.Utils.IO
import Prelude hiding(readFile)
import System.Glib.UTFString
  (
    glibToString
  )
import System.Posix.Env.ByteString
  (
    getEnv
  )
import qualified System.Posix.Process.ByteString as SPP
import System.Posix.Types
  (
    ProcessID
  )





    -----------------
    --[ Callbacks ]--
    -----------------




---- MAIN CALLBACK ENTRYPOINT ----


-- |Set callbacks for the whole gui, on hotkeys, events and stuff.
setGUICallbacks :: MyGUI -> IO ()
setGUICallbacks mygui = do

  _ <- clearStatusBar mygui `on` buttonActivated $ do
       popStatusbar mygui
       writeTVarIO (operationBuffer mygui) None

  -- menubar-file
  _ <- (menubarFileQuit . menubar) mygui `on` menuItemActivated $
    mainQuit

  -- menubar-help
  _ <- (menubarHelpAbout . menubar) mygui `on` menuItemActivated $
    liftIO showAboutDialog
  return ()

  -- key events
  _ <- rootWin mygui `on` keyPressEvent $ tryEvent $ do
    [Control] <- eventModifier
    "q"       <- fmap glibToString eventKeyName
    liftIO mainQuit

  return ()


-- |Set callbacks specific to a given view, on hotkeys, events and stuff.
setViewCallbacks :: MyGUI -> MyView -> IO ()
setViewCallbacks mygui myview = do
  view' <- readTVarIO $ view myview
  case view' of
    fmv@(FMTreeView treeView) -> do
      _ <- treeView `on` rowActivated
             $ (\_ _ -> withItems mygui myview open)

      -- drag events
      _ <- treeView `on` dragBegin $
        \_ -> withItems mygui myview moveInit
      _ <- treeView `on` dragDrop $
         \dc p ts -> do
           p'    <- treeViewConvertWidgetToTreeCoords treeView p
           mpath <- treeViewGetPathAtPos treeView p'
           case mpath of
             Nothing -> do
               dragFinish dc False False ts
               return False
             Just _  -> do
               atom  <- atomNew ("HSFM" :: String)
               dragGetData treeView dc atom ts
               return True
      _ <- treeView `on` dragDataReceived $
        \dc p _ ts ->
          liftIO $ do
            signalStopEmission treeView "drag_data_received"
            p'    <- treeViewConvertWidgetToTreeCoords treeView p
            mpath <- treeViewGetPathAtPos treeView p'
            case mpath of
              Nothing         -> dragFinish dc False False ts
              Just (tp, _, _) -> do
                mitem <- rawPathToItem myview tp
                forM_ mitem $ \item ->
                  operationFinal mygui myview (Just item)
                dragFinish dc True False ts

      commonGuiEvents fmv
      return ()
    fmv@(FMIconView iconView) -> do
      _ <- iconView `on` itemActivated
             $ (\_ -> withItems mygui myview open)
      commonGuiEvents fmv
      return ()
  where
    commonGuiEvents fmv = do
      let view = fmViewToContainer fmv

      -- GUI events
      _ <- urlBar myview `on` entryActivated $ urlGoTo mygui myview
      _ <- upViewB myview `on` buttonActivated $
           upDir mygui myview
      _ <- homeViewB myview `on` buttonActivated $
           goHome mygui myview
      _ <- refreshViewB myview `on` buttonActivated $ do
           cdir <- liftIO $ getCurrentDir myview
           refreshView' mygui myview cdir

      -- key events
      _ <- viewBox myview `on` keyPressEvent $ tryEvent $ do
        [Control] <- eventModifier
        "h"       <- fmap glibToString eventKeyName
        cdir <- liftIO $ getCurrentDir myview
        liftIO $ modifyTVarIO (settings mygui)
                              (\x -> x { showHidden = not . showHidden $ x})
                 >> refreshView' mygui myview cdir
      _ <- viewBox myview `on` keyPressEvent $ tryEvent $ do
        [Alt] <- eventModifier
        "Up"  <- fmap glibToString eventKeyName
        liftIO $ upDir mygui myview
      _ <- viewBox myview `on` keyPressEvent $ tryEvent $ do
        [Alt] <- eventModifier
        "Left"  <- fmap glibToString eventKeyName
        liftIO $ goHistoryPrev mygui myview
      _ <- viewBox myview `on` keyPressEvent $ tryEvent $ do
        [Alt] <- eventModifier
        "Right"  <- fmap glibToString eventKeyName
        liftIO $ goHistoryNext mygui myview
      _ <- view `on` keyPressEvent $ tryEvent $ do
        "Delete"  <- fmap glibToString eventKeyName
        liftIO $ withItems mygui myview del
      _ <- view `on` keyPressEvent $ tryEvent $ do
        []            <- eventModifier
        "Return"      <- fmap glibToString eventKeyName
        liftIO $ withItems mygui myview open
      _ <- view `on` keyPressEvent $ tryEvent $ do
        [Control] <- eventModifier
        "c"       <- fmap glibToString eventKeyName
        liftIO $ withItems mygui myview copyInit
      _ <- view `on` keyPressEvent $ tryEvent $ do
        [Control] <- eventModifier
        "x"       <- fmap glibToString eventKeyName
        liftIO $ withItems mygui myview moveInit
      _ <- viewBox myview `on` keyPressEvent $ tryEvent $ do
        [Control] <- eventModifier
        "v"       <- fmap glibToString eventKeyName
        liftIO $ operationFinal mygui myview Nothing
      _ <- viewBox myview `on` keyPressEvent $ tryEvent $ do
        [Control] <- eventModifier
        "t"       <- fmap glibToString eventKeyName
        liftIO $ void $ do
          cwd <- getCurrentDir myview
          newTab mygui createTreeView (path cwd)
      _ <- viewBox myview `on` keyPressEvent $ tryEvent $ do
        [Control] <- eventModifier
        "w"       <- fmap glibToString eventKeyName
        liftIO $ void $ closeTab mygui myview
      _ <- viewBox myview `on` keyPressEvent $ tryEvent $ do
        "F4"       <- fmap glibToString eventKeyName
        liftIO $ void $ openTerminalHere myview

      -- righ-click
      _ <- view `on` buttonPressEvent $ do
        eb <- eventButton
        t  <- eventTime
        case eb of
          RightButton -> do
              _ <- liftIO $ menuPopup (rcMenu . rcmenu $ myview)
                          $ Just (RightButton, t)
              -- this is just to not screw with current selection
              -- on right-click
              -- TODO: this misbehaves under IconView
              (x, y) <- eventCoordinates
              mpath  <- liftIO $ getPathAtPos fmv (x, y)
              case mpath of
                -- item under the cursor, only pass on the signal
                -- if the item under the cursor is not within the current
                -- selection
                (Just tp) -> do
                  selectedTps <- liftIO $ getSelectedTreePaths mygui myview
                  return $ elem tp selectedTps
                -- no item under the cursor, pass on the signal
                Nothing -> return False
          OtherButton 8 -> do
            liftIO $ goHistoryPrev mygui myview
            return False
          OtherButton 9 -> do
            liftIO $ goHistoryNext mygui myview
            return False
          -- not right-click, so pass on the signal
          _ -> return False

      -- right click menu
      _ <- (rcFileOpen . rcmenu) myview `on` menuItemActivated $
        liftIO $ withItems mygui myview open
      _ <- (rcFileExecute . rcmenu) myview `on` menuItemActivated $
        liftIO $ withItems mygui myview execute
      _ <- (rcFileNewRegFile . rcmenu) myview `on` menuItemActivated $
        liftIO $ newFile mygui myview
      _ <- (rcFileNewDir . rcmenu) myview `on` menuItemActivated $
        liftIO $ newDir mygui myview
      _ <- (rcFileCopy . rcmenu) myview `on` menuItemActivated $
        liftIO $ withItems mygui myview copyInit
      _ <- (rcFileRename . rcmenu) myview `on` menuItemActivated $
        liftIO $ withItems mygui myview renameF
      _ <- (rcFilePaste . rcmenu) myview `on` menuItemActivated $
        liftIO $ operationFinal mygui myview Nothing
      _ <- (rcFileDelete . rcmenu) myview `on` menuItemActivated $
        liftIO $ withItems mygui myview del
      _ <- (rcFileProperty . rcmenu) myview `on` menuItemActivated $
        liftIO $ withItems mygui myview showFilePropertyDialog
      _ <- (rcFileCut . rcmenu) myview `on` menuItemActivated $
        liftIO $ withItems mygui myview moveInit
      _ <- (rcFileIconView . rcmenu) myview `on` menuItemActivated $
        liftIO $ switchView mygui myview createIconView
      _ <- (rcFileTreeView . rcmenu) myview `on` menuItemActivated $
        liftIO $ switchView mygui myview createTreeView
      return ()

    getPathAtPos fmv (x, y) =
      case fmv of
        FMTreeView treeView -> do
          mp <- treeViewGetPathAtPos treeView (round x, round y)
          return $ fmap (\(p, _, _) -> p) mp
        FMIconView iconView ->
           fmap (\tp -> if null tp then Nothing else Just tp)
                  $ iconViewGetPathAtPos iconView (round x) (round y)




---- OTHER ----


openTerminalHere :: MyView -> IO ProcessID
openTerminalHere myview = do
  cwd <- (P.fromAbs . path) <$> getCurrentDir myview
  -- TODO: make terminal configurable
  SPP.forkProcess $ SPP.executeFile "sakura" True ["-d", cwd] Nothing




---- TAB OPERATIONS ----


-- |Closes the current tab, but only if there is more than one tab.
closeTab :: MyGUI -> MyView -> IO ()
closeTab mygui myview = do
  n <- notebookGetNPages (notebook mygui)
  when (n > 1) $ void $ destroyView mygui myview



---- FILE OPERATION CALLBACKS (COPY, MOVE, ...) ----


-- |Supposed to be used with 'withRows'. Deletes a file or directory.
del :: [Item] -> MyGUI -> MyView -> IO ()
del [item] _ _ = withErrorDialog $ do
  let cmsg  = "Really delete \"" ++ getFPasStr item ++ "\"?"
  withConfirmationDialog cmsg
    $ easyDelete . path $ item
-- this throws on the first error that occurs
del items@(_:_) _ _ = withErrorDialog $ do
  let cmsg  = "Really delete " ++ show (length items) ++ " files?"
  withConfirmationDialog cmsg
    $ forM_ items $ \item -> easyDelete . path $ item
del _ _ _ = withErrorDialog
              . throw $ InvalidOperation
                        "Operation not supported on multiple files"


-- |Initializes a file move operation.
moveInit :: [Item] -> MyGUI -> MyView -> IO ()
moveInit items@(_:_) mygui _ = do
  writeTVarIO (operationBuffer mygui) (FMove . PartialMove . map path $ items)
  let sbmsg = case items of
              (item:[]) -> "Move buffer: " ++ getFPasStr item
              _         -> "Move buffer: " ++ (show . length $ items)
                                           ++ " items"
  popStatusbar mygui
  void $ pushStatusBar mygui sbmsg
moveInit _ _ _ = withErrorDialog
                   . throw $ InvalidOperation
                             "No file selected!"

-- |Supposed to be used with 'withRows'. Initializes a file copy operation.
copyInit :: [Item] -> MyGUI -> MyView -> IO ()
copyInit items@(_:_) mygui _ = do
  writeTVarIO (operationBuffer mygui) (FCopy . PartialCopy . map path $ items)
  let sbmsg = case items of
              (item:[]) -> "Copy buffer: " ++ getFPasStr item
              _         -> "Copy buffer: " ++ (show . length $ items)
                                           ++ " items"
  popStatusbar mygui
  void $ pushStatusBar mygui sbmsg
copyInit _ _ _ = withErrorDialog
                   . throw $ InvalidOperation
                             "No file selected!"


-- |Finalizes a file operation, such as copy or move.
operationFinal :: MyGUI -> MyView -> Maybe Item -> IO ()
operationFinal mygui myview mitem = withErrorDialog $ do
  op <- readTVarIO (operationBuffer mygui)
  cdir <- case mitem of
            Nothing -> path <$> getCurrentDir myview
            Just x  -> return $ path x
  case op of
    FMove (PartialMove s) -> do
      let cmsg = "Really move " ++ imsg s
                  ++ " to \"" ++ P.fpToString (P.fromAbs cdir)
                  ++ "\"?"
      withConfirmationDialog cmsg . withCopyModeDialog
      -- TODO: cm ignored
        $ \cm -> do
             void $ runFileOp (FMove $ Move s cdir)
             popStatusbar mygui
             writeTVarIO (operationBuffer mygui) None
    FCopy (PartialCopy s) -> do
      let cmsg = "Really copy " ++ imsg s
                 ++ " to \"" ++ P.fpToString (P.fromAbs cdir)
                 ++ "\"?"
      withConfirmationDialog cmsg . withCopyModeDialog
      -- TODO: cm ignored
        $ \cm -> void $ runFileOp (FCopy $ Copy s cdir)
    _ -> return ()
  where
    imsg s = case s of
               (item:[]) -> "\"" ++ P.fpToString (P.fromAbs item) ++ "\""
               items     -> (show . length $ items) ++ " items"


-- |Create a new file.
newFile :: MyGUI -> MyView -> IO ()
newFile _ myview = withErrorDialog $ do
  mfn   <- textInputDialog "Enter file name"
  let pmfn = P.parseFn =<< P.userStringToFP <$> mfn
  for_ pmfn $ \fn -> do
    cdir  <- getCurrentDir myview
    createRegularFile (path cdir P.</> fn)


-- |Create a new directory.
newDir :: MyGUI -> MyView -> IO ()
newDir _ myview = withErrorDialog $ do
  mfn   <- textInputDialog "Enter directory name"
  let pmfn = P.parseFn =<< P.userStringToFP <$> mfn
  for_ pmfn $ \fn -> do
    cdir  <- getCurrentDir myview
    createDir (path cdir P.</> fn)


renameF :: [Item] -> MyGUI -> MyView -> IO ()
renameF [item] _ _ = withErrorDialog $ do
  mfn  <- textInputDialog "Enter new file name"
  let pmfn = P.parseFn =<< P.userStringToFP <$> mfn
  for_ pmfn $ \fn -> do
    let cmsg = "Really rename \"" ++ getFPasStr item
               ++ "\"" ++ " to \""
               ++ P.fpToString (P.fromAbs $ (P.dirname . path $ item)
                                             P.</> fn) ++ "\"?"
    withConfirmationDialog cmsg $
      HSFM.FileSystem.FileOperations.renameFile (path item)
                                                ((path item) P.</> fn)
renameF _ _ _ = withErrorDialog
                  . throw $ InvalidOperation
                            "Operation not supported on multiple files"




---- DIRECTORY TRAVERSAL AND FILE OPENING CALLBACKS ----


-- |Go to the url given at the 'urlBar' and visualize it in the given
-- treeView.
--
-- If the url is invalid, does nothing.
urlGoTo :: MyGUI -> MyView -> IO ()
urlGoTo mygui myview = withErrorDialog $ do
  fp <- entryGetText (urlBar myview)
  forM_ (P.parseAbs fp :: Maybe (Path Abs)) $ \fp' ->
      whenM (canOpenDirectory fp')
            (goDir mygui myview =<< (readFile getFileInfo $ fp'))


goHome :: MyGUI -> MyView -> IO ()
goHome mygui myview =  withErrorDialog $ do
  mhomedir <- getEnv "HOME"
  forM_ (P.parseAbs =<< mhomedir :: Maybe (Path Abs)) $ \fp' ->
      whenM (canOpenDirectory fp')
            (goDir mygui myview =<< (readFile getFileInfo $ fp'))


-- |Execute a given file.
execute :: [Item] -> MyGUI -> MyView -> IO ()
execute [item] _ _ = withErrorDialog $
  void $ executeFile (path item) []
execute _ _ _ = withErrorDialog
                  . throw $ InvalidOperation
                            "Operation not supported on multiple files"


-- |Supposed to be used with 'withRows'. Opens a file or directory.
open :: [Item] -> MyGUI -> MyView -> IO ()
open [item] mygui myview = withErrorDialog $
  case item of
    DirOrSym r -> do
      nv <- readFile getFileInfo $ path r
      goDir mygui myview nv
    r ->
      void $ openFile . path $ r
-- this throws on the first error that occurs
open (FileLikeList fs) _ _ = withErrorDialog $
  forM_ fs $ \f -> void $ openFile . path $ f
open _ _ _ = withErrorDialog
               . throw $ InvalidOperation
                         "Operation not supported on multiple files"


-- |Go up one directory and visualize it in the treeView.
upDir :: MyGUI -> MyView -> IO ()
upDir mygui myview = withErrorDialog $ do
  cdir <- getCurrentDir myview
  nv <- goUp cdir
  goDir mygui myview nv


-- |Helper that is invoked for any directory change operations.
goDir :: MyGUI -> MyView -> Item -> IO ()
goDir mygui myview item = do
  cdir <- getCurrentDir myview
  modifyTVarIO (history myview)
    (\(p, _) -> (path cdir `addHistory` p, []))
  refreshView' mygui myview item


-- |Go "back" in the history.
goHistoryPrev :: MyGUI -> MyView -> IO ()
goHistoryPrev mygui myview = do
  hs <- readTVarIO (history myview)
  case hs of
    ([], _) -> return ()
    (x:xs, _) -> do
      cdir <- getCurrentDir myview
      nv <- readFile getFileInfo $ x
      modifyTVarIO (history myview)
        (\(_, n) -> (xs, path cdir `addHistory` n))
      refreshView' mygui myview nv


-- |Go "forth" in the history.
goHistoryNext :: MyGUI -> MyView -> IO ()
goHistoryNext mygui myview = do
  hs <- readTVarIO (history myview)
  case hs of
    (_, []) -> return ()
    (_, x:xs) -> do
      cdir <- getCurrentDir myview
      nv <- readFile getFileInfo $ x
      modifyTVarIO (history myview)
        (\(p, _) -> (path cdir `addHistory` p, xs))
      refreshView' mygui myview nv