aboutsummaryrefslogtreecommitdiffstats
path: root/XMonad/Prompt.hs
blob: d0a7d68b111f6904d9e8d6073b82301d8def56cc (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
{-# LANGUAGE ExistentialQuantification #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  XMonad.Prompt
-- Copyright   :  (C) 2007 Andrea Rossato
-- License     :  BSD3
--
-- Maintainer  :  Spencer Janssen <spencerjanssen@gmail.com>
-- Stability   :  unstable
-- Portability :  unportable
--
-- A module for writing graphical prompts for XMonad
--
-----------------------------------------------------------------------------

module XMonad.Prompt
    ( -- * Usage
      -- $usage
      mkXPrompt
    , mkXPromptWithReturn
    , amberXPConfig
    , defaultXPConfig
    , greenXPConfig
    , XPType (..)
    , XPPosition (..)
    , XPConfig (..)
    , XPrompt (..)
    , XP
    , defaultXPKeymap
    , quit
    , killBefore, killAfter, startOfLine, endOfLine
    , pasteString, moveCursor
    , setInput, getInput
    , moveWord, killWord, deleteString
    , moveHistory, setSuccess, setDone
    , Direction1D(..)
    , ComplFunction
    -- * X Utilities
    -- $xutils
    , mkUnmanagedWindow
    , fillDrawable
    -- * Other Utilities
    -- $utils
    , mkComplFunFromList
    , mkComplFunFromList'
    -- * @nextCompletion@ implementations
    , getNextOfLastWord
    , getNextCompletion
    -- * List utilities
    , getLastWord
    , skipLastWord
    , splitInSubListsAt
    , breakAtSpace
    , uniqSort
    , decodeInput
    , encodeOutput
    , historyCompletion
    , historyCompletionP
    -- * History filters
    , deleteAllDuplicates
    , deleteConsecutive
    , HistoryMatches
    , initMatches
    , historyUpMatching
    ) where

import Prelude hiding (catch)

import XMonad  hiding (config, numlockMask, cleanMask)
import qualified XMonad as X (numlockMask)
import qualified XMonad.StackSet as W
import XMonad.Util.Font
import XMonad.Util.Types
import XMonad.Util.XSelection (getSelection)
import XMonad.Util.XUtils (fi)

import Control.Arrow ((&&&),first)
import Control.Concurrent (threadDelay)
import Control.Monad.Reader
import Control.Monad.State
import Control.Applicative ((<$>))
import Data.Char
import Data.Bits
import Data.Maybe
import Data.List
import Data.IORef
import Data.Set (fromList, toList)
import System.Directory
import System.IO
import System.Posix.Files
import Control.Exception hiding (handle)

import qualified Data.Map as M

-- $usage
-- For usage examples see "XMonad.Prompt.Shell",
-- "XMonad.Prompt.XMonad" or "XMonad.Prompt.Ssh"
--
-- TODO:
--
-- * scrolling the completions that don't fit in the window (?)

type XP = StateT XPState IO

data XPState =
    XPS { dpy                :: Display
        , rootw              :: !Window
        , win                :: !Window
        , screen             :: !Rectangle
        , complWin           :: Maybe Window
        , complWinDim        :: Maybe ComplWindowDim
        , completionFunction :: String -> IO [String]
        , showComplWin       :: Bool
        , gcon               :: !GC
        , fontS              :: !XMonadFont
        , xptype             :: !XPType
        , commandHistory     :: W.Stack String
        , offset             :: !Int
        , config             :: XPConfig
        , successful         :: Bool
        , numlockMask        :: KeyMask
        , done               :: Bool
        }

data XPConfig =
    XPC { font              :: String     -- ^ Font
        , bgColor           :: String     -- ^ Background color
        , fgColor           :: String     -- ^ Font color
        , fgHLight          :: String     -- ^ Font color of a highlighted completion entry
        , bgHLight          :: String     -- ^ Background color of a highlighted completion entry
        , borderColor       :: String     -- ^ Border color
        , promptBorderWidth :: !Dimension -- ^ Border width
        , position          :: XPPosition -- ^ Position: 'Top' or 'Bottom'
        , height            :: !Dimension -- ^ Window height
        , historySize       :: !Int       -- ^ The number of history entries to be saved
        , historyFilter     :: [String] -> [String]
                                         -- ^ a filter to determine which
                                         -- history entries to remember
        , promptKeymap      :: M.Map (KeyMask,KeySym) (XP ())
                                         -- ^ Mapping from key combinations to actions
        , completionKey     :: KeySym     -- ^ Key that should trigger completion
        , defaultText       :: String     -- ^ The text by default in the prompt line
        , autoComplete      :: Maybe Int  -- ^ Just x: if only one completion remains, auto-select it,
        , showCompletionOnTab :: Bool     -- ^ Only show list of completions when Tab was pressed
                                          --   and delay by x microseconds
        , searchPredicate   :: String -> String -> Bool
                                          -- ^ Given the typed string and a possible
                                          --   completion, is the completion valid?
        }

data XPType = forall p . XPrompt p => XPT p

instance Show XPType where
    show (XPT p) = showXPrompt p

instance XPrompt XPType where
    showXPrompt                 = show
    nextCompletion      (XPT t) = nextCompletion      t
    commandToComplete   (XPT t) = commandToComplete   t
    completionToCommand (XPT t) = completionToCommand t

-- | The class prompt types must be an instance of. In order to
-- create a prompt you need to create a data type, without parameters,
-- and make it an instance of this class, by implementing a simple
-- method, 'showXPrompt', which will be used to print the string to be
-- displayed in the command line window.
--
-- This is an example of a XPrompt instance definition:
--
-- >     instance XPrompt Shell where
-- >          showXPrompt Shell = "Run: "
class XPrompt t where

    -- | This method is used to print the string to be
    -- displayed in the command line window.
    showXPrompt :: t -> String

    -- | This method is used to generate the next completion to be
    -- printed in the command line when tab is pressed, given the
    -- string presently in the command line and the list of
    -- completion.
    nextCompletion :: t -> String -> [String] -> String
    nextCompletion = getNextOfLastWord

    -- | This method is used to generate the string to be passed to
    -- the completion function.
    commandToComplete :: t -> String -> String
    commandToComplete _ = getLastWord

    -- | This method is used to process each completion in order to
    -- generate the string that will be compared with the command
    -- presently displayed in the command line. If the prompt is using
    -- 'getNextOfLastWord' for implementing 'nextCompletion' (the
    -- default implementation), this method is also used to generate,
    -- from the returned completion, the string that will form the
    -- next command line when tab is pressed.
    completionToCommand :: t -> String -> String
    completionToCommand _ c = c

data XPPosition = Top
                | Bottom
                  deriving (Show,Read)

amberXPConfig, defaultXPConfig, greenXPConfig :: XPConfig

defaultXPConfig =
    XPC { font              = "-misc-fixed-*-*-*-*-12-*-*-*-*-*-*-*"
        , bgColor           = "grey22"
        , fgColor           = "grey80"
        , fgHLight          = "black"
        , bgHLight          = "grey"
        , borderColor       = "white"
        , promptBorderWidth = 1
        , promptKeymap      = defaultXPKeymap
        , completionKey     = xK_Tab
        , position          = Bottom
        , height            = 18
        , historySize       = 256
        , historyFilter     = id
        , defaultText       = []
        , autoComplete      = Nothing
        , showCompletionOnTab = False
        , searchPredicate   = isPrefixOf
        }
greenXPConfig = defaultXPConfig { fgColor = "green", bgColor = "black" }
amberXPConfig = defaultXPConfig { fgColor = "#ca8f2d", bgColor = "black", fgHLight = "#eaaf4c" }

type ComplFunction = String -> IO [String]

initState :: XPrompt p => Display -> Window -> Window -> Rectangle -> ComplFunction
          -> GC -> XMonadFont -> p -> [String] -> XPConfig -> KeyMask -> XPState
initState d rw w s compl gc fonts pt h c nm =
    XPS { dpy                = d
        , rootw              = rw
        , win                = w
        , screen             = s
        , complWin           = Nothing
        , complWinDim        = Nothing
        , completionFunction = compl
        , showComplWin       = not (showCompletionOnTab c)
        , gcon               = gc
        , fontS              = fonts
        , xptype             = XPT pt
        , commandHistory     = W.Stack { W.focus = defaultText c
                                       , W.up    = []
                                       , W.down  = h }
        , offset             = length (defaultText c)
        , config             = c
        , successful         = False
        , done               = False
        , numlockMask        = nm
        }

-- this would be much easier with functional references
command :: XPState -> String
command = W.focus . commandHistory

setCommand :: String -> XPState -> XPState
setCommand xs s = s { commandHistory = (commandHistory s) { W.focus = xs }}

-- | Sets the input string to the given value.
setInput :: String -> XP ()
setInput = modify . setCommand

-- | Returns the current input string. Intented for use in custom keymaps
-- where the 'get' or similar can't be used to retrieve it.
getInput :: XP String
getInput = gets command

-- | Same as 'mkXPrompt', except that the action function can have
--   type @String -> X a@, for any @a@, and the final action returned
--   by 'mkXPromptWithReturn' will have type @X (Maybe a)@.  @Nothing@
--   is yielded if the user cancels the prompt (by e.g. hitting Esc or
--   Ctrl-G).  For an example of use, see the 'XMonad.Prompt.Input'
--   module.
mkXPromptWithReturn :: XPrompt p => p -> XPConfig -> ComplFunction -> (String -> X a)  -> X (Maybe a)
mkXPromptWithReturn t conf compl action = do
  XConf { display = d, theRoot = rw } <- ask
  s    <- gets $ screenRect . W.screenDetail . W.current . windowset
  hist <- io readHistory
  w    <- io $ createWin d rw conf s
  io $ selectInput d w $ exposureMask .|. keyPressMask
  gc <- io $ createGC d w
  io $ setGraphicsExposures d gc False
  fs <- initXMF (font conf)
  numlock <- gets $ X.numlockMask
  let hs = fromMaybe [] $ M.lookup (showXPrompt t) hist
      st = initState d rw w s compl gc fs (XPT t) hs conf numlock
  st' <- io $ execStateT runXP st

  releaseXMF fs
  io $ freeGC d gc
  if successful st'
    then do
      io $ writeHistory $ M.insertWith
                                (\xs ys -> take (historySize conf)
                                        . historyFilter conf $ xs ++ ys)
                                (showXPrompt t) (historyFilter conf [command st'])
                                hist
                                -- we need to apply historyFilter before as well, since
                                -- otherwise the filter would not be applied if
                                -- there is no history
      Just <$> action (command st')
    else return Nothing

-- | Creates a prompt given:
--
-- * a prompt type, instance of the 'XPrompt' class.
--
-- * a prompt configuration ('defaultXPConfig' can be used as a
-- starting point)
--
-- * a completion function ('mkComplFunFromList' can be used to
-- create a completions function given a list of possible completions)
--
-- * an action to be run: the action must take a string and return 'XMonad.X' ()
mkXPrompt :: XPrompt p => p -> XPConfig -> ComplFunction -> (String -> X ()) -> X ()
mkXPrompt t conf compl action = mkXPromptWithReturn t conf compl action >> return ()

runXP :: XP ()
runXP = do
  (d,w) <- gets (dpy &&& win)
  status <- io $ grabKeyboard d w True grabModeAsync grabModeAsync currentTime
  when (status == grabSuccess) $ do
          updateWindows
          eventLoop handle
          io $ ungrabKeyboard d currentTime
  io $ destroyWindow d w
  destroyComplWin
  io $ sync d False

type KeyStroke = (KeySym, String)

eventLoop :: (KeyStroke -> Event -> XP ()) -> XP ()
eventLoop action = do
  d <- gets dpy
  (keysym,string,event) <- io $
            allocaXEvent $ \e -> do
              maskEvent d (exposureMask .|. keyPressMask) e
              ev <- getEvent e
              (ks,s) <- if ev_event_type ev == keyPress
                        then lookupString $ asKeyEvent e
                        else return (Nothing, "")
              return (ks,s,ev)
  action (fromMaybe xK_VoidSymbol keysym,string) event
  gets done >>= flip unless (eventLoop handle)

-- | Removes numlock and capslock from a keymask.
-- Duplicate of cleanMask from core, but in the
-- XP monad instead of X.
cleanMask :: KeyMask -> XP KeyMask
cleanMask msk = do
  numlock <- gets numlockMask
  let highMasks = 1 `shiftL` 12 - 1
  return (complement (numlock .|. lockMask) .&. msk .&. highMasks)

-- Main event handler
handle :: KeyStroke -> Event -> XP ()
handle ks@(sym,_) e@(KeyEvent {ev_event_type = t, ev_state = m}) = do
  complKey <- gets $ completionKey . config
  c <- getCompletions
  when (length c > 1) $ modify (\s -> s { showComplWin = True })
  if complKey == sym
     then completionHandle c ks e
     else when (t == keyPress) $ keyPressHandle m ks
handle _ (ExposeEvent {ev_window = w}) = do
  st <- get
  when (win st == w) updateWindows
handle _  _ = return ()

-- completion event handler
completionHandle ::  [String] -> KeyStroke -> Event -> XP ()
completionHandle c ks@(sym,_) (KeyEvent { ev_event_type = t, ev_state = m }) = do
  complKey <- gets $ completionKey . config
  case () of
    () | t == keyPress && sym == complKey ->
          do
            st <- get
            let updateState l =
                    let new_command = nextCompletion (xptype st) (command st) l
                    in modify $ \s -> setCommand new_command $ s { offset = length new_command }
                updateWins  l = redrawWindows l >>
                                eventLoop (completionHandle l)
            case c of
              []  -> updateWindows   >> eventLoop handle
              [x] -> updateState [x] >> getCompletions >>= updateWins
              l   -> updateState l   >> updateWins l
      | t == keyRelease && sym == complKey -> eventLoop (completionHandle c)
      | otherwise -> keyPressHandle m ks -- some other key, handle it normally
-- some other event: go back to main loop
completionHandle _ k e = handle k e


tryAutoComplete :: XP Bool
tryAutoComplete = do
    ac <- gets (autoComplete . config)
    case ac of
        Just d -> do cs <- getCompletions
                     case cs of
                         [c] -> runCompleted c d >> return True
                         _   -> return False
        Nothing    -> return False
  where runCompleted cmd delay = do
            st <- get
            let new_command = nextCompletion (xptype st) (command st) [cmd]
            modify $ setCommand "autocompleting..."
            updateWindows
            io $ threadDelay delay
            modify $ setCommand new_command
            return True

-- KeyPresses

defaultXPKeymap :: M.Map (KeyMask,KeySym) (XP ())
defaultXPKeymap = M.fromList $
  map (first $ (,) controlMask) -- control + <key>
  [ (xK_u, killBefore)
  , (xK_k, killAfter)
  , (xK_a, startOfLine)
  , (xK_e, endOfLine)
  , (xK_y, pasteString)
  , (xK_Right, moveWord Next)
  , (xK_Left, moveWord Prev)
  , (xK_Delete, killWord Next)
  , (xK_BackSpace, killWord Prev)
  , (xK_w, killWord Prev)
  , (xK_g, quit)
  , (xK_bracketleft, quit)
  ] ++
  map (first $ (,) 0)
  [ (xK_Return, setSuccess True >> setDone True)
  , (xK_KP_Enter, setSuccess True >> setDone True)
  , (xK_BackSpace, deleteString Prev)
  , (xK_Delete, deleteString Next)
  , (xK_Left, moveCursor Prev)
  , (xK_Right, moveCursor Next)
  , (xK_Home, startOfLine)
  , (xK_End, endOfLine)
  , (xK_Down, moveHistory W.focusUp')
  , (xK_Up, moveHistory W.focusDown')
  , (xK_Escape, quit)
  ]

keyPressHandle :: KeyMask -> KeyStroke -> XP ()
keyPressHandle m (ks,str) = do
  km <- gets (promptKeymap . config)
  mask <- cleanMask m
  case M.lookup (mask,ks) km of
    Just action -> action >> updateWindows
    Nothing -> case str of
                 "" -> eventLoop handle
                 _ -> when (mask .&. controlMask == 0) $ do
                                 insertString (decodeInput str)
                                 updateWindows
                                 completed <- tryAutoComplete
                                 when completed $ setSuccess True >> setDone True

setSuccess :: Bool -> XP ()
setSuccess b = modify $ \s -> s { successful = b }

setDone :: Bool -> XP ()
setDone b = modify $ \s -> s { done = b }

-- KeyPress and State

-- | Quit.
quit :: XP ()
quit = flushString >> setSuccess False >> setDone True

-- | Kill the portion of the command before the cursor
killBefore :: XP ()
killBefore =
  modify $ \s -> setCommand (drop (offset s) (command s)) $ s { offset  = 0 }

-- | Kill the portion of the command including and after the cursor
killAfter :: XP ()
killAfter =
  modify $ \s -> setCommand (take (offset s) (command s)) s

-- | Kill the next\/previous word
killWord :: Direction1D -> XP ()
killWord d = do
  o <- gets offset
  c <- gets command
  let (f,ss)        = splitAt o c
      delNextWord w =
          case w of
            ' ':x -> x
            word  -> snd . break isSpace $ word
      delPrevWord   = reverse . delNextWord . reverse
      (ncom,noff)   =
          case d of
            Next -> (f ++ delNextWord ss, o)
            Prev -> (delPrevWord f ++ ss, length $ delPrevWord f) -- laziness!!
  modify $ \s -> setCommand ncom $ s { offset = noff}

-- | Put the cursor at the end of line
endOfLine :: XP ()
endOfLine  =
    modify $ \s -> s { offset = length (command s)}

-- | Put the cursor at the start of line
startOfLine :: XP ()
startOfLine  =
    modify $ \s -> s { offset = 0 }

-- |  Flush the command string and reset the offset
flushString :: XP ()
flushString = modify $ \s -> setCommand "" $ s { offset = 0}

-- | Insert a character at the cursor position
insertString :: String -> XP ()
insertString str =
  modify $ \s -> setCommand (c (command s) (offset s)) $ s { offset = o (offset s)}
  where o oo = oo + length str
        c oc oo | oo >= length oc = oc ++ str
                | otherwise = f ++ str ++ ss
                where (f,ss) = splitAt oo oc

-- | Insert the current X selection string at the cursor position.
pasteString :: XP ()
pasteString = join $ io $ liftM insertString getSelection

-- | Remove a character at the cursor position
deleteString :: Direction1D -> XP ()
deleteString d =
  modify $ \s -> setCommand (c (command s) (offset s)) $ s { offset = o (offset s)}
  where o oo = if d == Prev then max 0 (oo - 1) else oo
        c oc oo
            | oo >= length oc && d == Prev = take (oo - 1) oc
            | oo <  length oc && d == Prev = take (oo - 1) f ++ ss
            | oo <  length oc && d == Next = f ++ tail ss
            | otherwise = oc
            where (f,ss) = splitAt oo oc

-- | move the cursor one position
moveCursor :: Direction1D -> XP ()
moveCursor d =
  modify $ \s -> s { offset = o (offset s) (command s)}
  where o oo c = if d == Prev then max 0 (oo - 1) else min (length c) (oo + 1)

-- | move the cursor one word
moveWord :: Direction1D -> XP ()
moveWord d = do
  c <- gets command
  o <- gets offset
  let (f,ss) = splitAt o c
      lenToS = length . fst . break isSpace
      ln p s = case p s of
                 ' ':x -> 1 + lenToS x
                 x     -> lenToS x
      newoff = case d of
                 Prev -> o - ln reverse f
                 Next -> o + ln id ss
  modify $ \s -> s { offset = newoff }

moveHistory :: (W.Stack String -> W.Stack String) -> XP ()
moveHistory f = modify $ \s -> let ch = f $ commandHistory s
                               in s { commandHistory = ch
                                    , offset         = length $ W.focus ch }

-- X Stuff

updateWindows :: XP ()
updateWindows = do
  d <- gets dpy
  drawWin
  c <- getCompletions
  case c  of
    [] -> destroyComplWin >> return ()
    l  -> redrawComplWin l
  io $ sync d False

redrawWindows :: [String] -> XP ()
redrawWindows c = do
  d <- gets dpy
  drawWin
  case c of
    [] -> return ()
    l  -> redrawComplWin l
  io $ sync d False

createWin :: Display -> Window -> XPConfig -> Rectangle -> IO Window
createWin d rw c s = do
  let (x,y) = case position c of
                Top -> (0,0)
                Bottom -> (0, rect_height s - height c)
  w <- mkUnmanagedWindow d (defaultScreenOfDisplay d) rw
                      (rect_x s + x) (rect_y s + fi y) (rect_width s) (height c)
  mapWindow d w
  return w

drawWin :: XP ()
drawWin = do
  st <- get
  let (c,(d,(w,gc))) = (config &&& dpy &&& win &&& gcon) st
      scr = defaultScreenOfDisplay d
      wh = widthOfScreen scr
      ht = height c
      bw = promptBorderWidth c
  Just bgcolor <- io $ initColor d (bgColor c)
  Just border  <- io $ initColor d (borderColor c)
  p <- io $ createPixmap d w wh ht
                         (defaultDepthOfScreen scr)
  io $ fillDrawable d p gc border bgcolor (fi bw) wh ht
  printPrompt p
  io $ copyArea d p w gc 0 0 wh ht 0 0
  io $ freePixmap d p

printPrompt :: Drawable -> XP ()
printPrompt drw = do
  st <- get
  let (gc,(c,(d,fs))) = (gcon &&& config &&& dpy &&& fontS) st
      (prt,(com,off)) = (show . xptype &&& command &&& offset) st
      str = prt ++ com
      -- break the string in 3 parts: till the cursor, the cursor and the rest
      (f,p,ss) = if off >= length com
                 then (str, " ","") -- add a space: it will be our cursor ;-)
                 else let (a,b) = (splitAt off com)
                      in (prt ++ a, [head b], tail b)
      ht = height c
  fsl <- io $ textWidthXMF (dpy st) fs f
  psl <- io $ textWidthXMF (dpy st) fs p
  (asc,desc) <- io $ textExtentsXMF fs str
  let y = fi $ ((ht - fi (asc + desc)) `div` 2) + fi asc
      x = (asc + desc) `div` 2

  let draw = printStringXMF d drw fs gc
  -- print the first part
  draw (fgColor c) (bgColor c) x y f
  -- reverse the colors and print the "cursor" ;-)
  draw (bgColor c) (fgColor c) (x + fromIntegral fsl) y p
  -- reverse the colors and print the rest of the string
  draw (fgColor c) (bgColor c) (x + fromIntegral (fsl + psl)) y ss

-- Completions

getCompletions :: XP [String]
getCompletions = do
  s <- get
  io $ completionFunction s (commandToComplete (xptype s) (command s))
       `catch` \_ -> return []

setComplWin :: Window -> ComplWindowDim -> XP ()
setComplWin w wi =
  modify (\s -> s { complWin = Just w, complWinDim = Just wi })

destroyComplWin :: XP ()
destroyComplWin = do
  d  <- gets dpy
  cw <- gets complWin
  case cw of
    Just w -> do io $ destroyWindow d w
                 modify (\s -> s { complWin = Nothing, complWinDim = Nothing })
    Nothing -> return ()

type ComplWindowDim = (Position,Position,Dimension,Dimension,Columns,Rows)
type Rows = [Position]
type Columns = [Position]

createComplWin :: ComplWindowDim -> XP Window
createComplWin wi@(x,y,wh,ht,_,_) = do
  st <- get
  let d = dpy st
      scr = defaultScreenOfDisplay d
  w <- io $ mkUnmanagedWindow d scr (rootw st)
                      x y wh ht
  io $ mapWindow d w
  setComplWin w wi
  return w

getComplWinDim :: [String] -> XP ComplWindowDim
getComplWinDim compl = do
  st <- get
  let (c,(scr,fs)) = (config &&& screen &&& fontS) st
      wh = rect_width scr
      ht = height c

  tws <- mapM (textWidthXMF (dpy st) fs) compl
  let max_compl_len =  fromIntegral ((fi ht `div` 2) + maximum tws)
      columns = max 1 $ wh `div` fi max_compl_len
      rem_height =  rect_height scr - ht
      (rows,r) = length compl `divMod` fi columns
      needed_rows = max 1 (rows + if r == 0 then 0 else 1)
      actual_max_number_of_rows = rem_height `div` ht
      actual_rows = min actual_max_number_of_rows (fi needed_rows)
      actual_height = actual_rows * ht
      (x,y) = case position c of
                Top -> (0,ht)
                Bottom -> (0, (0 + rem_height - actual_height))
  (asc,desc) <- io $ textExtentsXMF fs $ head compl
  let yp = fi $ (ht + fi (asc - desc)) `div` 2
      xp = (asc + desc) `div` 2
      yy = map fi . take (fi actual_rows) $ [yp,(yp + ht)..]
      xx = take (fi columns) [xp,(xp + max_compl_len)..]

  return (rect_x scr + x, rect_y scr + fi y, wh, actual_height, xx, yy)

drawComplWin :: Window -> [String] -> XP ()
drawComplWin w compl = do
  st <- get
  let c   = config st
      d   = dpy st
      scr = defaultScreenOfDisplay d
      bw  = promptBorderWidth c
      gc  = gcon st
  Just bgcolor <- io $ initColor d (bgColor c)
  Just border  <- io $ initColor d (borderColor c)

  (_,_,wh,ht,xx,yy) <- getComplWinDim compl

  p <- io $ createPixmap d w wh ht
                         (defaultDepthOfScreen scr)
  io $ fillDrawable d p gc border bgcolor (fi bw) wh ht
  let ac = splitInSubListsAt (length yy) (take (length xx * length yy) compl)
  printComplList d p gc (fgColor c) (bgColor c) xx yy ac
  io $ copyArea d p w gc 0 0 wh ht 0 0
  io $ freePixmap d p

redrawComplWin ::  [String] -> XP ()
redrawComplWin compl = do
  st <- get
  nwi <- getComplWinDim compl
  let recreate = do destroyComplWin
                    w <- createComplWin nwi
                    drawComplWin w compl
  if compl /= [] && showComplWin st
     then case complWin st of
            Just w -> case complWinDim st of
                        Just wi -> if nwi == wi -- complWinDim did not change
                                   then drawComplWin w compl -- so update
                                   else recreate
                        Nothing -> recreate
            Nothing -> recreate
     else destroyComplWin

printComplList :: Display -> Drawable -> GC -> String -> String
               -> [Position] -> [Position] -> [[String]] -> XP ()
printComplList d drw gc fc bc xs ys sss =
    zipWithM_ (\x ss ->
        zipWithM_ (\y s -> do
            st <- get
            let (f,b) = if completionToCommand (xptype st) s == commandToComplete (xptype st) (command st)
                            then (fgHLight $ config st,bgHLight $ config st)
                            else (fc,bc)
            printStringXMF d drw (fontS st) gc f b x y s)
        ys ss) xs sss

-- History

type History = M.Map String [String]

emptyHistory :: History
emptyHistory = M.empty

getHistoryFile :: IO FilePath
getHistoryFile = fmap (++ "/history") $ getAppUserDataDirectory "xmonad"

readHistory :: IO History
readHistory = catch readHist (const (return emptyHistory))
 where
    readHist = do
        path <- getHistoryFile
        xs <- bracket (openFile path ReadMode) hClose hGetLine
        readIO xs

writeHistory :: History -> IO ()
writeHistory hist = do
  path <- getHistoryFile
  catch (writeFile path (show hist)) $ const $ hPutStrLn stderr "error in writing"
  setFileMode path mode
    where mode = ownerReadMode .|. ownerWriteMode

-- $xutils

-- | Fills a 'Drawable' with a rectangle and a border
fillDrawable :: Display -> Drawable -> GC -> Pixel -> Pixel
             -> Dimension -> Dimension -> Dimension -> IO ()
fillDrawable d drw gc border bgcolor bw wh ht = do
  -- we start with the border
  setForeground d gc border
  fillRectangle d drw gc 0 0 wh ht
  -- here foreground means the background of the text
  setForeground d gc bgcolor
  fillRectangle d drw gc (fi bw) (fi bw) (wh - (bw * 2)) (ht - (bw * 2))

-- | Creates a window with the attribute override_redirect set to True.
-- Windows Managers should not touch this kind of windows.
mkUnmanagedWindow :: Display -> Screen -> Window -> Position
                  -> Position -> Dimension -> Dimension -> IO Window
mkUnmanagedWindow d s rw x y w h = do
  let visual = defaultVisualOfScreen s
      attrmask = cWOverrideRedirect
  allocaSetWindowAttributes $
         \attributes -> do
           set_override_redirect attributes True
           createWindow d rw x y w h 0 (defaultDepthOfScreen s)
                        inputOutput visual attrmask attributes

-- $utils

-- | This function takes a list of possible completions and returns a
-- completions function to be used with 'mkXPrompt'
mkComplFunFromList :: [String] -> String -> IO [String]
mkComplFunFromList _ [] = return []
mkComplFunFromList l s =
  return $ filter (\x -> take (length s) x == s) l

-- | This function takes a list of possible completions and returns a
-- completions function to be used with 'mkXPrompt'. If the string is
-- null it will return all completions.
mkComplFunFromList' :: [String] -> String -> IO [String]
mkComplFunFromList' l [] = return l
mkComplFunFromList' l s =
  return $ filter (\x -> take (length s) x == s) l


-- | Given the prompt type, the command line and the completion list,
-- return the next completion in the list for the last word of the
-- command line. This is the default 'nextCompletion' implementation.
getNextOfLastWord :: XPrompt t => t -> String -> [String] -> String
getNextOfLastWord t c l = skipLastWord c ++ completionToCommand t (l !! ni)
    where ni = case commandToComplete t c `elemIndex` map (completionToCommand t) l of
                 Just i -> if i >= length l - 1 then 0 else i + 1
                 Nothing -> 0

-- | An alternative 'nextCompletion' implementation: given a command
-- and a completion list, get the next completion in the list matching
-- the whole command line.
getNextCompletion :: String -> [String] -> String
getNextCompletion c l = l !! idx
    where idx = case c `elemIndex` l of
                  Just i  -> if i >= length l - 1 then 0 else i + 1
                  Nothing -> 0

-- | Given a maximum length, splits a list into sublists
splitInSubListsAt :: Int -> [a] -> [[a]]
splitInSubListsAt _ [] = []
splitInSubListsAt i x = f : splitInSubListsAt i rest
    where (f,rest) = splitAt i x

-- | Gets the last word of a string or the whole string if formed by
-- only one word
getLastWord :: String -> String
getLastWord = reverse . fst . breakAtSpace . reverse

-- | Skips the last word of the string, if the string is composed by
-- more then one word. Otherwise returns the string.
skipLastWord :: String -> String
skipLastWord = reverse . snd . breakAtSpace . reverse

breakAtSpace :: String -> (String, String)
breakAtSpace s
    | " \\" `isPrefixOf` s2 = (s1 ++ " " ++ s1', s2')
    | otherwise = (s1, s2)
      where (s1, s2 ) = break isSpace s
            (s1',s2') = breakAtSpace $ tail s2

-- | 'historyCompletion' provides a canned completion function much like
--   'getShellCompl'; you pass it to mkXPrompt, and it will make completions work
--   from the query history stored in ~\/.xmonad\/history.
historyCompletion :: ComplFunction
historyCompletion = historyCompletionP (const True)

-- | Like 'historyCompletion' but only uses history data from Prompts whose
-- name satisfies the given predicate.
historyCompletionP :: (String -> Bool) -> ComplFunction
historyCompletionP p x = fmap (toComplList . M.filterWithKey (const . p)) readHistory
    where toComplList = deleteConsecutive . filter (isInfixOf x) . M.fold (++) []

-- | Sort a list and remove duplicates. Like 'deleteAllDuplicates', but trades off
--   laziness and stability for efficiency.
uniqSort :: Ord a => [a] -> [a]
uniqSort = toList . fromList

-- | Functions to be used with the 'historyFilter' setting.
-- 'deleteAllDuplicates' will remove all duplicate entries.
-- 'deleteConsecutive' will only remove duplicate elements
-- immediately next to each other.
deleteAllDuplicates, deleteConsecutive :: [String] -> [String]
deleteAllDuplicates = nub
deleteConsecutive = map head . group

newtype HistoryMatches = HistoryMatches (IORef ([String],[String]))

-- | Initializes a new HistoryMatches structure to be passed
-- to historyUpMatching
initMatches :: (Functor m, MonadIO m) => m HistoryMatches
initMatches = HistoryMatches <$> liftIO (newIORef ([],[]))

-- | Retrieve the next history element that starts with
-- the current input. Pass it an IORef containing two empty lists
-- when creating the prompt. Example:
--
-- > ..
-- > ((modMask,xK_p), shellPrompt . myPrompt =<< initMatches)
-- > ..
-- > myPrompt ref = defaultPrompt
-- >   { promptKeymap = M.union [((0,xK_Up), historyMatching ref)] (promptKeymap defaultPrompt)
-- >   , .. }
--
historyUpMatching :: HistoryMatches -> XP ()
historyUpMatching hm@(HistoryMatches ref) = do
  (completed,completions) <- io $ readIORef ref
  input <- getInput
  if input `elem` completed
     then case completions of
            (c:cs) -> do
                modify (setCommand c)
                modify $ \s -> s { offset = length c }
                io $ writeIORef ref (c:completed,cs)
            _ -> return ()
     else do -- the user typed something new, recompute completions
       io . writeIORef ref . ((,) [input]) . filterMatching input =<< gets commandHistory
       historyUpMatching hm
    where filterMatching :: String -> W.Stack String -> [String]
          filterMatching prefix =
              filter (prefix `isPrefixOf`) . tail . cycle . nub . W.integrate