aboutsummaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/Shared.hs
blob: ef9f66aa704f2d4be0b632d418706ec081493e2f (plain)
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
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
{-# LANGUAGE DeriveDataTypeable, CPP, MultiParamTypeClasses,
    FlexibleContexts, ScopedTypeVariables, PatternGuards,
    ViewPatterns #-}
{-
Copyright (C) 2006-2015 John MacFarlane <jgm@berkeley.edu>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-}

{- |
   Module      : Text.Pandoc.Shared
   Copyright   : Copyright (C) 2006-2015 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>
   Stability   : alpha
   Portability : portable

Utility functions and definitions used by the various Pandoc modules.
-}
module Text.Pandoc.Shared (
                     -- * List processing
                     splitBy,
                     splitByIndices,
                     splitStringByIndices,
                     substitute,
                     ordNub,
                     -- * Text processing
                     backslashEscapes,
                     escapeStringUsing,
                     stripTrailingNewlines,
                     trim,
                     triml,
                     trimr,
                     stripFirstAndLast,
                     camelCaseToHyphenated,
                     toRomanNumeral,
                     escapeURI,
                     tabFilter,
                     -- * Date/time
                     normalizeDate,
                     -- * Pandoc block and inline list processing
                     orderedListMarkers,
                     normalizeSpaces,
                     extractSpaces,
                     normalize,
                     normalizeInlines,
                     normalizeBlocks,
                     removeFormatting,
                     stringify,
                     capitalize,
                     compactify,
                     compactify',
                     compactify'DL,
                     Element (..),
                     hierarchicalize,
                     uniqueIdent,
                     isHeaderBlock,
                     headerShift,
                     isTightList,
                     addMetaField,
                     makeMeta,
                     -- * TagSoup HTML handling
                     renderTags',
                     -- * File handling
                     inDirectory,
                     getDefaultReferenceDocx,
                     getDefaultReferenceODT,
                     readDataFile,
                     readDataFileUTF8,
                     fetchItem,
                     fetchItem',
                     openURL,
                     collapseFilePath,
                     -- * Error handling
                     err,
                     warn,
                     mapLeft,
                     hush,
                     -- * Safe read
                     safeRead,
                     -- * Temp directory
                     withTempDir
                    ) where

import Text.Pandoc.Definition
import Text.Pandoc.Walk
import Text.Pandoc.MediaBag (MediaBag, lookupMedia)
import Text.Pandoc.Builder (Inlines, Blocks, ToMetaValue(..))
import qualified Text.Pandoc.Builder as B
import qualified Text.Pandoc.UTF8 as UTF8
import System.Environment (getProgName)
import System.Exit (exitWith, ExitCode(..))
import Data.Char ( toLower, isLower, isUpper, isAlpha,
                   isLetter, isDigit, isSpace )
import Data.List ( find, stripPrefix, intercalate )
import qualified Data.Map as M
import Network.URI ( escapeURIString, isURI, nonStrictRelativeTo,
                     unEscapeString, parseURIReference, isAllowedInURI )
import qualified Data.Set as Set
import System.Directory
import System.FilePath (joinPath, splitDirectories, pathSeparator, isPathSeparator)
import Text.Pandoc.MIME (MimeType, getMimeType)
import System.FilePath ( (</>), takeExtension, dropExtension)
import Data.Generics (Typeable, Data)
import qualified Control.Monad.State as S
import qualified Control.Exception as E
import Control.Applicative ((<$>))
import Control.Monad (msum, unless, MonadPlus(..))
import Text.Pandoc.Pretty (charWidth)
import Text.Pandoc.Compat.Locale (defaultTimeLocale)
import Data.Time
import Data.Time.Clock.POSIX
import System.IO (stderr)
import System.IO.Temp
import Text.HTML.TagSoup (renderTagsOptions, RenderOptions(..), Tag(..),
         renderOptions)
import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as B8
import Text.Pandoc.Compat.Monoid
import Data.ByteString.Base64 (decodeLenient)
import Data.Sequence (ViewR(..), ViewL(..), viewl, viewr)
import qualified Data.Text as T (toUpper, pack, unpack)
import Data.ByteString.Lazy (toChunks, fromChunks)
import qualified Data.ByteString.Lazy as BL

#ifdef EMBED_DATA_FILES
import Text.Pandoc.Data (dataFiles)
#else
import Paths_pandoc (getDataFileName)
#endif
#ifdef HTTP_CLIENT
import Network.HTTP.Client (httpLbs, parseUrl, withManager,
                            responseBody, responseHeaders,
                            Request(port,host))
import Network.HTTP.Client.Internal (addProxy)
import Network.HTTP.Client.TLS (tlsManagerSettings)
import System.Environment (getEnv)
import Network.HTTP.Types.Header ( hContentType)
import Network (withSocketsDo)
import Codec.Archive.Zip
#else
import Network.URI (parseURI)
import Network.HTTP (findHeader, rspBody,
                     RequestMethod(..), HeaderName(..), mkRequest)
import Network.Browser (browse, setAllowRedirects, setOutHandler, request)
#endif

--
-- List processing
--

-- | Split list by groups of one or more sep.
splitBy :: (a -> Bool) -> [a] -> [[a]]
splitBy _ [] = []
splitBy isSep lst =
  let (first, rest) = break isSep lst
      rest'         = dropWhile isSep rest
  in  first:(splitBy isSep rest')

splitByIndices :: [Int] -> [a] -> [[a]]
splitByIndices [] lst = [lst]
splitByIndices (x:xs) lst = first:(splitByIndices (map (\y -> y - x)  xs) rest)
  where (first, rest) = splitAt x lst

-- | Split string into chunks divided at specified indices.
splitStringByIndices :: [Int] -> [Char] -> [[Char]]
splitStringByIndices [] lst = [lst]
splitStringByIndices (x:xs) lst =
  let (first, rest) = splitAt' x lst in
  first : (splitStringByIndices (map (\y -> y - x) xs) rest)

splitAt' :: Int -> [Char] -> ([Char],[Char])
splitAt' _ []          = ([],[])
splitAt' n xs | n <= 0 = ([],xs)
splitAt' n (x:xs)      = (x:ys,zs)
  where (ys,zs) = splitAt' (n - charWidth x) xs

-- | Replace each occurrence of one sublist in a list with another.
substitute :: (Eq a) => [a] -> [a] -> [a] -> [a]
substitute _ _ [] = []
substitute [] _ xs = xs
substitute target replacement lst@(x:xs) =
    case stripPrefix target lst of
      Just lst' -> replacement ++ substitute target replacement lst'
      Nothing   -> x : substitute target replacement xs

ordNub :: (Ord a) => [a] -> [a]
ordNub l = go Set.empty l
  where
    go _ [] = []
    go s (x:xs) = if x `Set.member` s then go s xs
                                      else x : go (Set.insert x s) xs

--
-- Text processing
--

-- | Returns an association list of backslash escapes for the
-- designated characters.
backslashEscapes :: [Char]    -- ^ list of special characters to escape
                 -> [(Char, String)]
backslashEscapes = map (\ch -> (ch, ['\\',ch]))

-- | Escape a string of characters, using an association list of
-- characters and strings.
escapeStringUsing :: [(Char, String)] -> String -> String
escapeStringUsing _ [] = ""
escapeStringUsing escapeTable (x:xs) =
  case (lookup x escapeTable) of
       Just str  -> str ++ rest
       Nothing   -> x:rest
  where rest = escapeStringUsing escapeTable xs

-- | Strip trailing newlines from string.
stripTrailingNewlines :: String -> String
stripTrailingNewlines = reverse . dropWhile (== '\n') . reverse

-- | Remove leading and trailing space (including newlines) from string.
trim :: String -> String
trim = triml . trimr

-- | Remove leading space (including newlines) from string.
triml :: String -> String
triml = dropWhile (`elem` " \r\n\t")

-- | Remove trailing space (including newlines) from string.
trimr :: String -> String
trimr = reverse . triml . reverse

-- | Strip leading and trailing characters from string
stripFirstAndLast :: String -> String
stripFirstAndLast str =
  drop 1 $ take ((length str) - 1) str

-- | Change CamelCase word to hyphenated lowercase (e.g., camel-case).
camelCaseToHyphenated :: String -> String
camelCaseToHyphenated [] = ""
camelCaseToHyphenated (a:b:rest) | isLower a && isUpper b =
  a:'-':(toLower b):(camelCaseToHyphenated rest)
camelCaseToHyphenated (a:rest) = (toLower a):(camelCaseToHyphenated rest)

-- | Convert number < 4000 to uppercase roman numeral.
toRomanNumeral :: Int -> String
toRomanNumeral x =
  if x >= 4000 || x < 0
     then "?"
     else case x of
              _ | x >= 1000 -> "M" ++ toRomanNumeral (x - 1000)
              _ | x >= 900  -> "CM" ++ toRomanNumeral (x - 900)
              _ | x >= 500  -> "D" ++ toRomanNumeral (x - 500)
              _ | x >= 400  -> "CD" ++ toRomanNumeral (x - 400)
              _ | x >= 100  -> "C" ++ toRomanNumeral (x - 100)
              _ | x >= 90   -> "XC" ++ toRomanNumeral (x - 90)
              _ | x >= 50   -> "L"  ++ toRomanNumeral (x - 50)
              _ | x >= 40   -> "XL" ++ toRomanNumeral (x - 40)
              _ | x >= 10   -> "X" ++ toRomanNumeral (x - 10)
              _ | x == 9    -> "IX"
              _ | x >= 5    -> "V" ++ toRomanNumeral (x - 5)
              _ | x == 4    -> "IV"
              _ | x >= 1    -> "I" ++ toRomanNumeral (x - 1)
              _             -> ""

-- | Escape whitespace in URI.
escapeURI :: String -> String
escapeURI = escapeURIString (not . isSpace)

-- | Convert tabs to spaces and filter out DOS line endings.
-- Tabs will be preserved if tab stop is set to 0.
tabFilter :: Int       -- ^ Tab stop
          -> String    -- ^ Input
          -> String
tabFilter tabStop =
  let go _ [] = ""
      go _ ('\n':xs) = '\n' : go tabStop xs
      go _ ('\r':'\n':xs) = '\n' : go tabStop xs
      go _ ('\r':xs) = '\n' : go tabStop xs
      go spsToNextStop ('\t':xs) =
        if tabStop == 0
           then '\t' : go tabStop xs
           else replicate spsToNextStop ' ' ++ go tabStop xs
      go 1 (x:xs) =
        x : go tabStop xs
      go spsToNextStop (x:xs) =
        x : go (spsToNextStop - 1) xs
  in  go tabStop

--
-- Date/time
--

-- | Parse a date and convert (if possible) to "YYYY-MM-DD" format.
normalizeDate :: String -> Maybe String
normalizeDate s = fmap (formatTime defaultTimeLocale "%F")
  (msum $ map (\fs -> parsetimeWith fs s) formats :: Maybe Day)
   where parsetimeWith = parseTime defaultTimeLocale
         formats = ["%x","%m/%d/%Y", "%D","%F", "%d %b %Y",
                    "%d %B %Y", "%b. %d, %Y", "%B %d, %Y", "%Y"]

--
-- Pandoc block and inline list processing
--

-- | Generate infinite lazy list of markers for an ordered list,
-- depending on list attributes.
orderedListMarkers :: (Int, ListNumberStyle, ListNumberDelim) -> [String]
orderedListMarkers (start, numstyle, numdelim) =
  let singleton c = [c]
      nums = case numstyle of
                     DefaultStyle -> map show [start..]
                     Example      -> map show [start..]
                     Decimal      -> map show [start..]
                     UpperAlpha   -> drop (start - 1) $ cycle $
                                     map singleton ['A'..'Z']
                     LowerAlpha   -> drop (start - 1) $ cycle $
                                     map singleton ['a'..'z']
                     UpperRoman   -> map toRomanNumeral [start..]
                     LowerRoman   -> map (map toLower . toRomanNumeral) [start..]
      inDelim str = case numdelim of
                            DefaultDelim -> str ++ "."
                            Period       -> str ++ "."
                            OneParen     -> str ++ ")"
                            TwoParens    -> "(" ++ str ++ ")"
  in  map inDelim nums

-- | Normalize a list of inline elements: remove leading and trailing
-- @Space@ elements, collapse double @Space@s into singles, and
-- remove empty Str elements.
normalizeSpaces :: [Inline] -> [Inline]
normalizeSpaces = cleanup . dropWhile isSpaceOrEmpty
 where  cleanup []              = []
        cleanup (Space:rest)    = case dropWhile isSpaceOrEmpty rest of
                                        []     -> []
                                        (x:xs) -> Space : x : cleanup xs
        cleanup ((Str ""):rest) = cleanup rest
        cleanup (x:rest)        = x : cleanup rest

isSpaceOrEmpty :: Inline -> Bool
isSpaceOrEmpty Space = True
isSpaceOrEmpty (Str "") = True
isSpaceOrEmpty _ = False

-- | Extract the leading and trailing spaces from inside an inline element
-- and place them outside the element.

extractSpaces :: (Inlines -> Inlines) -> Inlines -> Inlines
extractSpaces f is =
  let contents = B.unMany is
      left  = case viewl contents of
                    (Space :< _) -> B.space
                    _            -> mempty
      right = case viewr contents of
                    (_ :> Space) -> B.space
                    _            -> mempty in
  (left <> f (B.trimInlines . B.Many $ contents) <> right)

-- | Normalize @Pandoc@ document, consolidating doubled 'Space's,
-- combining adjacent 'Str's and 'Emph's, remove 'Null's and
-- empty elements, etc.
normalize :: Pandoc -> Pandoc
normalize (Pandoc (Meta meta) blocks) =
  Pandoc (Meta $ M.map go meta) (normalizeBlocks blocks)
  where go (MetaInlines xs) = MetaInlines $ normalizeInlines xs
        go (MetaBlocks xs)  = MetaBlocks  $ normalizeBlocks xs
        go (MetaList ms)    = MetaList $ map go ms
        go (MetaMap m)      = MetaMap $ M.map go m
        go x                = x

normalizeBlocks :: [Block] -> [Block]
normalizeBlocks (Null : xs) = normalizeBlocks xs
normalizeBlocks (Div attr bs : xs) =
  Div attr (normalizeBlocks bs) : normalizeBlocks xs
normalizeBlocks (BlockQuote bs : xs) =
  case normalizeBlocks bs of
       []    -> normalizeBlocks xs
       bs'   -> BlockQuote bs' : normalizeBlocks xs
normalizeBlocks (BulletList [] : xs) = normalizeBlocks xs
normalizeBlocks (BulletList items : xs) =
  BulletList (map normalizeBlocks items) : normalizeBlocks xs
normalizeBlocks (OrderedList _ [] : xs) = normalizeBlocks xs
normalizeBlocks (OrderedList attr items : xs) =
  OrderedList attr (map normalizeBlocks items) : normalizeBlocks xs
normalizeBlocks (DefinitionList [] : xs) = normalizeBlocks xs
normalizeBlocks (DefinitionList items : xs) =
  DefinitionList (map go items) : normalizeBlocks xs
  where go (ils, bs) = (normalizeInlines ils, map normalizeBlocks bs)
normalizeBlocks (RawBlock _ "" : xs) = normalizeBlocks xs
normalizeBlocks (RawBlock f x : xs) =
   case normalizeBlocks xs of
        (RawBlock f' x' : rest) | f' == f ->
          RawBlock f (x ++ ('\n':x')) : rest
        rest -> RawBlock f x : rest
normalizeBlocks (Para ils : xs) =
  case normalizeInlines ils of
       []   -> normalizeBlocks xs
       ils' -> Para ils' : normalizeBlocks xs
normalizeBlocks (Plain ils : xs) =
  case normalizeInlines ils of
       []   -> normalizeBlocks xs
       ils' -> Plain ils' : normalizeBlocks xs
normalizeBlocks (Header lev attr ils : xs) =
  Header lev attr (normalizeInlines ils) : normalizeBlocks xs
normalizeBlocks (Table capt aligns widths hdrs rows : xs) =
  Table (normalizeInlines capt) aligns widths
    (map normalizeBlocks hdrs) (map (map normalizeBlocks) rows)
  : normalizeBlocks xs
normalizeBlocks (x:xs) = x : normalizeBlocks xs
normalizeBlocks [] = []

normalizeInlines :: [Inline] -> [Inline]
normalizeInlines (Str x : ys) =
  case concat (x : map fromStr strs) of
        ""     -> rest
        n      -> Str n : rest
   where
     (strs, rest)  = span isStr $ normalizeInlines ys
     isStr (Str _) = True
     isStr _       = False
     fromStr (Str z) = z
     fromStr _       = error "normalizeInlines - fromStr - not a Str"
normalizeInlines (Space : ys) =
  if null rest
     then []
     else Space : rest
   where isSp Space = True
         isSp _     = False
         rest       = dropWhile isSp $ normalizeInlines ys
normalizeInlines (Emph xs : zs) =
  case normalizeInlines zs of
       (Emph ys : rest) -> normalizeInlines $
         Emph (normalizeInlines $ xs ++ ys) : rest
       rest -> case normalizeInlines xs of
                    []  -> rest
                    xs' -> Emph xs' : rest
normalizeInlines (Strong xs : zs) =
  case normalizeInlines zs of
       (Strong ys : rest) -> normalizeInlines $
         Strong (normalizeInlines $ xs ++ ys) : rest
       rest -> case normalizeInlines xs of
                    []  -> rest
                    xs' -> Strong xs' : rest
normalizeInlines (Subscript xs : zs) =
  case normalizeInlines zs of
       (Subscript ys : rest) -> normalizeInlines $
         Subscript (normalizeInlines $ xs ++ ys) : rest
       rest -> case normalizeInlines xs of
                    []  -> rest
                    xs' -> Subscript xs' : rest
normalizeInlines (Superscript xs : zs) =
  case normalizeInlines zs of
       (Superscript ys : rest) -> normalizeInlines $
         Superscript (normalizeInlines $ xs ++ ys) : rest
       rest -> case normalizeInlines xs of
                    []  -> rest
                    xs' -> Superscript xs' : rest
normalizeInlines (SmallCaps xs : zs) =
  case normalizeInlines zs of
       (SmallCaps ys : rest) -> normalizeInlines $
         SmallCaps (normalizeInlines $ xs ++ ys) : rest
       rest -> case normalizeInlines xs of
                    []  -> rest
                    xs' -> SmallCaps xs' : rest
normalizeInlines (Strikeout xs : zs) =
  case normalizeInlines zs of
       (Strikeout ys : rest) -> normalizeInlines $
         Strikeout (normalizeInlines $ xs ++ ys) : rest
       rest -> case normalizeInlines xs of
                    []  -> rest
                    xs' -> Strikeout xs' : rest
normalizeInlines (RawInline _ [] : ys) = normalizeInlines ys
normalizeInlines (RawInline f xs : zs) =
  case normalizeInlines zs of
       (RawInline f' ys : rest) | f == f' -> normalizeInlines $
         RawInline f (xs ++ ys) : rest
       rest -> RawInline f xs : rest
normalizeInlines (Code _ "" : ys) = normalizeInlines ys
normalizeInlines (Code attr xs : zs) =
  case normalizeInlines zs of
       (Code attr' ys : rest) | attr == attr' -> normalizeInlines $
         Code attr (xs ++ ys) : rest
       rest -> Code attr xs : rest
-- allow empty spans, they may carry identifiers etc.
-- normalizeInlines (Span _ [] : ys) = normalizeInlines ys
normalizeInlines (Span attr xs : zs) =
  case normalizeInlines zs of
       (Span attr' ys : rest) | attr == attr' -> normalizeInlines $
         Span attr (normalizeInlines $ xs ++ ys) : rest
       rest -> Span attr (normalizeInlines xs) : rest
normalizeInlines (Note bs : ys) = Note (normalizeBlocks bs) :
  normalizeInlines ys
normalizeInlines (Quoted qt ils : ys) =
  Quoted qt (normalizeInlines ils) : normalizeInlines ys
normalizeInlines (Link ils t : ys) =
  Link (normalizeInlines ils) t : normalizeInlines ys
normalizeInlines (Image ils t : ys) =
  Image (normalizeInlines ils) t : normalizeInlines ys
normalizeInlines (Cite cs ils : ys) =
  Cite cs (normalizeInlines ils) : normalizeInlines ys
normalizeInlines (x : xs) = x : normalizeInlines xs
normalizeInlines [] = []

-- | Extract inlines, removing formatting.
removeFormatting :: Walkable Inline a => a -> [Inline]
removeFormatting = query go . walk deNote
  where go :: Inline -> [Inline]
        go (Str xs)     = [Str xs]
        go Space        = [Space]
        go (Code _ x)   = [Str x]
        go (Math _ x)   = [Str x]
        go LineBreak    = [Space]
        go _            = []
        deNote (Note _) = Str ""
        deNote x        = x

-- | Convert pandoc structure to a string with formatting removed.
-- Footnotes are skipped (since we don't want their contents in link
-- labels).
stringify :: Walkable Inline a => a -> String
stringify = query go . walk deNote
  where go :: Inline -> [Char]
        go Space = " "
        go (Str x) = x
        go (Code _ x) = x
        go (Math _ x) = x
        go LineBreak = " "
        go _ = ""
        deNote (Note _) = Str ""
        deNote x = x

-- | Bring all regular text in a pandoc structure to uppercase.
--
-- This function correctly handles cases where a lowercase character doesn't
-- match to a single uppercase character – e.g. “Straße” would be converted
-- to “STRASSE”, not “STRAßE”.
capitalize :: Walkable Inline a => a -> a
capitalize = walk go
  where go :: Inline -> Inline
        go (Str s) = Str (T.unpack $ T.toUpper $ T.pack s)
        go x       = x

-- | Change final list item from @Para@ to @Plain@ if the list contains
-- no other @Para@ blocks.
compactify :: [[Block]]  -- ^ List of list items (each a list of blocks)
           -> [[Block]]
compactify [] = []
compactify items =
  case (init items, last items) of
       (_,[])          -> items
       (others, final) ->
            case last final of
                 Para a -> case (filter isPara $ concat items) of
                                -- if this is only Para, change to Plain
                                [_] -> others ++ [init final ++ [Plain a]]
                                _   -> items
                 _      -> items

-- | Change final list item from @Para@ to @Plain@ if the list contains
-- no other @Para@ blocks.  Like compactify, but operates on @Blocks@ rather
-- than @[Block]@.
compactify' :: [Blocks]  -- ^ List of list items (each a list of blocks)
           -> [Blocks]
compactify' [] = []
compactify' items =
  let (others, final) = (init items, last items)
  in  case reverse (B.toList final) of
           (Para a:xs) -> case [Para x | Para x <- concatMap B.toList items] of
                            -- if this is only Para, change to Plain
                            [_] -> others ++ [B.fromList (reverse $ Plain a : xs)]
                            _   -> items
           _      -> items

-- | Like @compactify'@, but acts on items of definition lists.
compactify'DL :: [(Inlines, [Blocks])] -> [(Inlines, [Blocks])]
compactify'DL items =
  let defs = concatMap snd items
  in  case reverse (concatMap B.toList defs) of
           (Para x:xs)
             | not (any isPara xs) ->
                   let (t,ds) = last items
                       lastDef = B.toList $ last ds
                       ds' = init ds ++
                             if null lastDef
                                then [B.fromList lastDef]
                                else [B.fromList $ init lastDef ++ [Plain x]]
                    in init items ++ [(t, ds')]
             | otherwise           -> items
           _                       -> items

isPara :: Block -> Bool
isPara (Para _) = True
isPara _        = False

-- | Data structure for defining hierarchical Pandoc documents
data Element = Blk Block
             | Sec Int [Int] Attr [Inline] [Element]
             --    lvl  num attributes label    contents
             deriving (Eq, Read, Show, Typeable, Data)

instance Walkable Inline Element where
  walk f (Blk x) = Blk (walk f x)
  walk f (Sec lev nums attr ils elts) = Sec lev nums attr (walk f ils) (walk f elts)
  walkM f (Blk x) = Blk `fmap` walkM f x
  walkM f (Sec lev nums attr ils elts) = do
    ils' <- walkM f ils
    elts' <- walkM f elts
    return $ Sec lev nums attr ils' elts'
  query f (Blk x) = query f x
  query f (Sec _ _ _ ils elts) = query f ils <> query f elts

instance Walkable Block Element where
  walk f (Blk x) = Blk (walk f x)
  walk f (Sec lev nums attr ils elts) = Sec lev nums attr (walk f ils) (walk f elts)
  walkM f (Blk x) = Blk `fmap` walkM f x
  walkM f (Sec lev nums attr ils elts) = do
    ils' <- walkM f ils
    elts' <- walkM f elts
    return $ Sec lev nums attr ils' elts'
  query f (Blk x) = query f x
  query f (Sec _ _ _ ils elts) = query f ils <> query f elts


-- | Convert Pandoc inline list to plain text identifier.  HTML
-- identifiers must start with a letter, and may contain only
-- letters, digits, and the characters _-.
inlineListToIdentifier :: [Inline] -> String
inlineListToIdentifier =
  dropWhile (not . isAlpha) . intercalate "-" . words .
    map (nbspToSp . toLower) .
    filter (\c -> isLetter c || isDigit c || c `elem` "_-. ") .
    stringify
 where nbspToSp '\160'     =  ' '
       nbspToSp x          =  x

-- | Convert list of Pandoc blocks into (hierarchical) list of Elements
hierarchicalize :: [Block] -> [Element]
hierarchicalize blocks = S.evalState (hierarchicalizeWithIds blocks) []

hierarchicalizeWithIds :: [Block] -> S.State [Int] [Element]
hierarchicalizeWithIds [] = return []
hierarchicalizeWithIds ((Header level attr@(_,classes,_) title'):xs) = do
  lastnum <- S.get
  let lastnum' = take level lastnum
  let newnum = case length lastnum' of
                    x | "unnumbered" `elem` classes -> []
                      | x >= level -> init lastnum' ++ [last lastnum' + 1]
                      | otherwise -> lastnum ++
                           replicate (level - length lastnum - 1) 0 ++ [1]
  unless (null newnum) $ S.put newnum
  let (sectionContents, rest) = break (headerLtEq level) xs
  sectionContents' <- hierarchicalizeWithIds sectionContents
  rest' <- hierarchicalizeWithIds rest
  return $ Sec level newnum attr title' sectionContents' : rest'
hierarchicalizeWithIds ((Div ("",["references"],[])
                         (Header level (ident,classes,kvs) title' : xs)):ys) =
  hierarchicalizeWithIds ((Header level (ident,("references":classes),kvs)
                           title') : (xs ++ ys))
hierarchicalizeWithIds (x:rest) = do
  rest' <- hierarchicalizeWithIds rest
  return $ (Blk x) : rest'

headerLtEq :: Int -> Block -> Bool
headerLtEq level (Header l _ _) = l <= level
headerLtEq level (Div ("",["references"],[]) (Header l _ _ : _))  = l <= level
headerLtEq _ _ = False

-- | Generate a unique identifier from a list of inlines.
-- Second argument is a list of already used identifiers.
uniqueIdent :: [Inline] -> [String] -> String
uniqueIdent title' usedIdents =
  let baseIdent = case inlineListToIdentifier title' of
                        ""   -> "section"
                        x    -> x
      numIdent n = baseIdent ++ "-" ++ show n
  in  if baseIdent `elem` usedIdents
        then case find (\x -> numIdent x `notElem` usedIdents) ([1..60000] :: [Int]) of
                  Just x  -> numIdent x
                  Nothing -> baseIdent   -- if we have more than 60,000, allow repeats
        else baseIdent

-- | True if block is a Header block.
isHeaderBlock :: Block -> Bool
isHeaderBlock (Header _ _ _) = True
isHeaderBlock _ = False

-- | Shift header levels up or down.
headerShift :: Int -> Pandoc -> Pandoc
headerShift n = walk shift
  where shift :: Block -> Block
        shift (Header level attr inner) = Header (level + n) attr inner
        shift x                         = x

-- | Detect if a list is tight.
isTightList :: [[Block]] -> Bool
isTightList = all firstIsPlain
  where firstIsPlain (Plain _ : _) = True
        firstIsPlain _             = False

-- | Set a field of a 'Meta' object.  If the field already has a value,
-- convert it into a list with the new value appended to the old value(s).
addMetaField :: ToMetaValue a
             => String
             -> a
             -> Meta
             -> Meta
addMetaField key val (Meta meta) =
  Meta $ M.insertWith combine key (toMetaValue val) meta
  where combine newval (MetaList xs) = MetaList (xs ++ tolist newval)
        combine newval x             = MetaList [x, newval]
        tolist (MetaList ys)         = ys
        tolist y                     = [y]

-- | Create 'Meta' from old-style title, authors, date.  This is
-- provided to ease the transition from the old API.
makeMeta :: [Inline] -> [[Inline]] -> [Inline] -> Meta
makeMeta title authors date =
      addMetaField "title" (B.fromList title)
    $ addMetaField "author" (map B.fromList authors)
    $ addMetaField "date" (B.fromList date)
    $ nullMeta

--
-- TagSoup HTML handling
--

-- | Render HTML tags.
renderTags' :: [Tag String] -> String
renderTags' = renderTagsOptions
               renderOptions{ optMinimize = matchTags ["hr", "br", "img",
                                                       "meta", "link"]
                            , optRawTag   = matchTags ["script", "style"] }
              where matchTags = \tags -> flip elem tags . map toLower

--
-- File handling
--

-- | Perform an IO action in a directory, returning to starting directory.
inDirectory :: FilePath -> IO a -> IO a
inDirectory path action = E.bracket
                             getCurrentDirectory
                             setCurrentDirectory
                             (const $ setCurrentDirectory path >> action)

getDefaultReferenceDocx :: Maybe FilePath -> IO Archive
getDefaultReferenceDocx datadir = do
  let paths = ["[Content_Types].xml",
               "_rels/.rels",
               "docProps/app.xml",
               "docProps/core.xml",
               "word/document.xml",
               "word/fontTable.xml",
               "word/footnotes.xml",
               "word/numbering.xml",
               "word/settings.xml",
               "word/webSettings.xml",
               "word/styles.xml",
               "word/_rels/document.xml.rels",
               "word/_rels/footnotes.xml.rels",
               "word/theme/theme1.xml"]
  let toLazy = fromChunks . (:[])
  let pathToEntry path = do epochtime <- (floor . utcTimeToPOSIXSeconds) <$>
                                          getCurrentTime
                            contents <- toLazy <$> readDataFile datadir
                                                       ("docx/" ++ path)
                            return $ toEntry path epochtime contents
  mbArchive <- case datadir of
                    Nothing   -> return Nothing
                    Just d    -> do
                       exists <- doesFileExist (d </> "reference.docx")
                       if exists
                          then return (Just (d </> "reference.docx"))
                          else return Nothing
  case mbArchive of
     Just arch -> toArchive <$> BL.readFile arch
     Nothing   -> foldr addEntryToArchive emptyArchive <$>
                     mapM pathToEntry paths

getDefaultReferenceODT :: Maybe FilePath -> IO Archive
getDefaultReferenceODT datadir = do
  let paths = ["mimetype",
               "manifest.rdf",
               "styles.xml",
               "content.xml",
               "meta.xml",
               "settings.xml",
               "Configurations2/accelerator/current.xml",
               "Thumbnails/thumbnail.png",
               "META-INF/manifest.xml"]
  let pathToEntry path = do epochtime <- floor `fmap` getPOSIXTime
                            contents <- (fromChunks . (:[])) `fmap`
                                          readDataFile datadir ("odt/" ++ path)
                            return $ toEntry path epochtime contents
  mbArchive <- case datadir of
                    Nothing   -> return Nothing
                    Just d    -> do
                       exists <- doesFileExist (d </> "reference.odt")
                       if exists
                          then return (Just (d </> "reference.odt"))
                          else return Nothing
  case mbArchive of
     Just arch -> toArchive <$> BL.readFile arch
     Nothing   -> foldr addEntryToArchive emptyArchive <$>
                     mapM pathToEntry paths


readDefaultDataFile :: FilePath -> IO BS.ByteString
readDefaultDataFile "reference.docx" =
  (BS.concat . toChunks . fromArchive) <$> getDefaultReferenceDocx Nothing
readDefaultDataFile "reference.odt" =
  (BS.concat . toChunks . fromArchive) <$> getDefaultReferenceODT Nothing
readDefaultDataFile fname =
#ifdef EMBED_DATA_FILES
  case lookup (makeCanonical fname) dataFiles of
    Nothing       -> err 97 $ "Could not find data file " ++ fname
    Just contents -> return contents
  where makeCanonical = joinPath . transformPathParts . splitDirectories
        transformPathParts = reverse . foldl go []
        go as     "."  = as
        go (_:as) ".." = as
        go as     x    = x : as
#else
  getDataFileName fname' >>= checkExistence >>= BS.readFile
    where fname' = if fname == "README" then fname else "data" </> fname
#endif

checkExistence :: FilePath -> IO FilePath
checkExistence fn = do
  exists <- doesFileExist fn
  if exists
     then return fn
     else err 97 ("Could not find data file " ++ fn)

-- | Read file from specified user data directory or, if not found there, from
-- Cabal data directory.
readDataFile :: Maybe FilePath -> FilePath -> IO BS.ByteString
readDataFile Nothing fname = readDefaultDataFile fname
readDataFile (Just userDir) fname = do
  exists <- doesFileExist (userDir </> fname)
  if exists
     then BS.readFile (userDir </> fname)
     else readDefaultDataFile fname

-- | Same as 'readDataFile' but returns a String instead of a ByteString.
readDataFileUTF8 :: Maybe FilePath -> FilePath -> IO String
readDataFileUTF8 userDir fname =
  UTF8.toString `fmap` readDataFile userDir fname

-- | Fetch an image or other item from the local filesystem or the net.
-- Returns raw content and maybe mime type.
fetchItem :: Maybe String -> String
          -> IO (Either E.SomeException (BS.ByteString, Maybe MimeType))
fetchItem sourceURL s =
  case (sourceURL >>= parseURIReference . ensureEscaped, ensureEscaped s) of
       (_, s') | isURI s'  -> openURL s'
       (Just u, s') -> -- try fetching from relative path at source
          case parseURIReference s' of
               Just u' -> openURL $ show $ u' `nonStrictRelativeTo` u
               Nothing -> openURL s' -- will throw error
       (Nothing, _) -> E.try readLocalFile -- get from local file system
  where readLocalFile = do
          cont <- BS.readFile fp
          return (cont, mime)
        dropFragmentAndQuery = takeWhile (\c -> c /= '?' && c /= '#')
        fp = unEscapeString $ dropFragmentAndQuery s
        mime = case takeExtension fp of
                    ".gz" -> getMimeType $ dropExtension fp
                    ".svgz" -> getMimeType $ dropExtension fp ++ ".svg"
                    x     -> getMimeType x
        ensureEscaped x@(_:':':'\\':_) = x -- likely windows path
        ensureEscaped x = escapeURIString isAllowedInURI x

-- | Like 'fetchItem', but also looks for items in a 'MediaBag'.
fetchItem' :: MediaBag -> Maybe String -> String
           -> IO (Either E.SomeException (BS.ByteString, Maybe MimeType))
fetchItem' media sourceURL s = do
  case lookupMedia s media of
       Nothing -> fetchItem sourceURL s
       Just (mime, bs) -> return $ Right (BS.concat $ toChunks bs, Just mime)

-- | Read from a URL and return raw data and maybe mime type.
openURL :: String -> IO (Either E.SomeException (BS.ByteString, Maybe MimeType))
openURL u
  | Just u' <- stripPrefix "data:" u =
    let mime     = takeWhile (/=',') u'
        contents = B8.pack $ unEscapeString $ drop 1 $ dropWhile (/=',') u'
    in  return $ Right (decodeLenient contents, Just mime)
#ifdef HTTP_CLIENT
  | otherwise = withSocketsDo $ E.try $ do
     req <- parseUrl u
     (proxy :: Either E.SomeException String) <- E.try $ getEnv "http_proxy"
     let req' = case proxy of
                     Left _   -> req
                     Right pr -> case parseUrl pr of
                                      Just r  -> addProxy (host r) (port r) req
                                      Nothing -> req
     resp <- withManager tlsManagerSettings $ httpLbs req'
     return (BS.concat $ toChunks $ responseBody resp,
             UTF8.toString `fmap` lookup hContentType (responseHeaders resp))
#else
  | otherwise = E.try $ getBodyAndMimeType `fmap` browse
              (do S.liftIO $ UTF8.hPutStrLn stderr $ "Fetching " ++ u ++ "..."
                  setOutHandler $ const (return ())
                  setAllowRedirects True
                  request (getRequest' u'))
  where getBodyAndMimeType (_, r) = (rspBody r, findHeader HdrContentType r)
        getRequest' uriString = case parseURI uriString of
                                   Nothing -> error ("Not a valid URL: " ++
                                                        uriString)
                                   Just v  -> mkRequest GET v
        u' = escapeURIString (/= '|') u  -- pipes are rejected by Network.URI
#endif

--
-- Error reporting
--

err :: Int -> String -> IO a
err exitCode msg = do
  name <- getProgName
  UTF8.hPutStrLn stderr $ name ++ ": " ++ msg
  exitWith $ ExitFailure exitCode
  return undefined

warn :: String -> IO ()
warn msg = do
  name <- getProgName
  UTF8.hPutStrLn stderr $ name ++ ": " ++ msg

mapLeft :: (a -> b) -> Either a c -> Either b c
mapLeft f (Left x) = Left (f x)
mapLeft _ (Right x) = Right x

hush :: Either a b -> Maybe b
hush (Left _) = Nothing
hush (Right x) = Just x

-- | Remove intermediate "." and ".." directories from a path.
--
-- > collapseFilePath "./foo" == "foo"
-- > collapseFilePath "/bar/../baz" == "/baz"
-- > collapseFilePath "/../baz" == "/../baz"
-- > collapseFilePath "parent/foo/baz/../bar" ==  "parent/foo/bar"
-- > collapseFilePath "parent/foo/baz/../../bar" ==  "parent/bar"
-- > collapseFilePath "parent/foo/.." ==  "parent"
-- > collapseFilePath "/parent/foo/../../bar" ==  "/bar"
collapseFilePath :: FilePath -> FilePath
collapseFilePath = joinPath . reverse . foldl go [] . splitDirectories
  where
    go rs "." = rs
    go r@(p:rs) ".." = case p of
                            ".." -> ("..":r)
                            (checkPathSeperator -> Just True) -> ("..":r)
                            _ -> rs
    go _ (checkPathSeperator -> Just True) = [[pathSeparator]]
    go rs x = x:rs
    isSingleton [] = Nothing
    isSingleton [x] = Just x
    isSingleton _ = Nothing
    checkPathSeperator = fmap isPathSeparator . isSingleton

--
-- Safe read
--

safeRead :: (MonadPlus m, Read a) => String -> m a
safeRead s = case reads s of
                  (d,x):_
                    | all isSpace x -> return d
                  _                 -> mzero

--
-- Temp directory
--

withTempDir :: String -> (FilePath -> IO a) -> IO a
withTempDir =
#ifdef _WINDOWS
  withTempDirectory "."
#else
  withSystemTempDirectory
#endif