{-# LANGUAGE TypeSynonymInstances, MultiParamTypeClasses, DeriveDataTypeable #-}
{-# LANGUAGE PatternGuards, FlexibleContexts, FlexibleInstances #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  XMonad.Layout.BoringWindows
-- Copyright   :  (c) 2008  David Roundy <droundy@darcs.net>
-- License     :  BSD3-style (see LICENSE)
--
-- Maintainer  :  none
-- Stability   :  unstable
-- Portability :  unportable
--
-- BoringWindows is an extension to allow windows to be marked boring
--
-----------------------------------------------------------------------------

module XMonad.Layout.BoringWindows (
                                   -- * Usage
                                   -- $usage
                                   boringWindows, boringAuto,
                                   markBoring, clearBoring,
                                   focusUp, focusDown, focusMaster,

                                   UpdateBoring(UpdateBoring),
                                   BoringMessage(Replace,Merge),
                                   BoringWindows()
                                  ) where

import XMonad.Layout.LayoutModifier(ModifiedLayout(..),
                                    LayoutModifier(handleMessOrMaybeModifyIt, redoLayout))
import XMonad(Typeable, LayoutClass, Message, X, fromMessage,
              sendMessage, windows, withFocused, Window)
import Control.Applicative((<$>))
import Control.Monad(Monad(return, (>>)))
import Data.List((\\), union)
import Data.Maybe(Maybe(..), maybe, fromMaybe, listToMaybe,
                  maybeToList)
import qualified Data.Map as M
import qualified XMonad.StackSet as W

-- $usage
-- You can use this module with the following in your
-- @~\/.xmonad\/xmonad.hs@:
--
-- > import XMonad.Layout.BoringWindows
--
-- Then edit your @layoutHook@ by adding the layout modifier:
--
-- > myLayout = boringWindows (Full ||| etc..)
-- > main = xmonad defaultConfig { layoutHook = myLayout }
--
-- Then to your keybindings, add:
--
-- > , ((modm, xK_j), focusUp)
-- > , ((modm, xK_k), focusDown)
-- > , ((modm, xK_m), focusMaster)
--
-- For more detailed instructions on editing the layoutHook see:
--
-- "XMonad.Doc.Extending#Editing_the_layout_hook"


data BoringMessage = FocusUp | FocusDown | FocusMaster | IsBoring Window | ClearBoring
                     | Replace String [Window]
                     | Merge String [Window]
                     deriving ( Read, Show, Typeable )

instance Message BoringMessage

-- | UpdateBoring is sent before attempting to view another boring window, so
-- that layouts have a chance to mark boring windows.
data UpdateBoring = UpdateBoring
    deriving (Typeable)
instance Message UpdateBoring

markBoring, clearBoring, focusUp, focusDown, focusMaster :: X ()
markBoring = withFocused (sendMessage . IsBoring)
clearBoring = sendMessage ClearBoring
focusUp = sendMessage UpdateBoring >> sendMessage FocusUp
focusDown = sendMessage UpdateBoring >> sendMessage FocusDown
focusMaster = sendMessage UpdateBoring >> sendMessage FocusMaster

data BoringWindows a = BoringWindows
    { namedBoring :: M.Map String [a] -- ^ store borings with a specific source
    , chosenBoring :: [a]             -- ^ user-chosen borings
    , hiddenBoring :: Maybe [a]       -- ^ maybe mark hidden windows
    } deriving (Show,Read,Typeable)

boringWindows :: (LayoutClass l a, Eq a) => l a -> ModifiedLayout BoringWindows l a
boringWindows = ModifiedLayout (BoringWindows M.empty [] Nothing)

-- | Mark windows that are not given rectangles as boring
boringAuto :: (LayoutClass l a, Eq a) => l a -> ModifiedLayout BoringWindows l a
boringAuto = ModifiedLayout (BoringWindows M.empty [] (Just []))

instance LayoutModifier BoringWindows Window where
    redoLayout (b@BoringWindows { hiddenBoring = bs }) _r mst arrs = do
        let bs' = W.integrate' mst \\ map fst arrs
        return (arrs, Just $ b { hiddenBoring = const bs' <$> bs } )

    handleMessOrMaybeModifyIt bst@(BoringWindows nbs cbs lbs) m
        | Just (Replace k ws) <- fromMessage m
        , maybe True (ws/=) (M.lookup k nbs) =
            let nnb = if null ws then M.delete k nbs
                          else M.insert k ws nbs
            in rjl bst { namedBoring = nnb }
        | Just (Merge k ws) <- fromMessage m
        , maybe True (not . null . (ws \\)) (M.lookup k nbs) =
            rjl bst { namedBoring = M.insertWith union k ws nbs }
        | Just (IsBoring w) <- fromMessage m , w `notElem` cbs =
            rjl bst { chosenBoring = w:cbs }
        | Just ClearBoring <- fromMessage m, not (null cbs) =
            rjl bst { namedBoring = M.empty, chosenBoring = []}
        | Just FocusUp <- fromMessage m =
                            do windows $ W.modify' $ skipBoring W.focusUp'
                               return Nothing
        | Just FocusDown <- fromMessage m =
                            do windows $ W.modify' $ skipBoring W.focusDown'
                               return Nothing
        | Just FocusMaster <- fromMessage m =
                            do windows $ W.modify'
                                            $ skipBoring W.focusDown' -- wiggle focus to make sure
                                            . skipBoring W.focusUp'   -- no boring window gets the focus
                                            . focusMaster'
                               return Nothing
        where skipBoring f st = fromMaybe st $ listToMaybe
                                $ filter ((`notElem` W.focus st:bs) . W.focus)
                                $ take (length $ W.integrate st)
                                $ iterate f st
              bs = concat $ cbs:maybeToList lbs ++ M.elems nbs
              rjl = return . Just . Left
    handleMessOrMaybeModifyIt _ _ = return Nothing

-- | Variant of 'focusMaster' that works on a
-- 'Stack' rather than an entire 'StackSet'.
focusMaster' :: W.Stack a -> W.Stack a
focusMaster' c@(W.Stack _ [] _) = c
focusMaster' (W.Stack t ls rs) = W.Stack x [] (xs ++ t : rs) where (x:xs) = reverse ls