about summary refs log blame commit diff
path: root/configs/shared/emacs/.emacs.d/elpa/circe-20180525.531/lui.el
blob: 07cc758f29c03831bcc4b6f15bd29f9db19cae8b (plain) (tree)
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
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513








































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                   
;;; lui.el --- Linewise User Interface -*- lexical-binding: t -*-

;; Copyright (C) 2005 - 2016  Jorgen Schaefer

;; Author: Jorgen Schaefer <forcer@forcix.cx>
;; URL: https://github.com/jorgenschaefer/circe/wiki/Lui

;; 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 3 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, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; Lui is a library for other Emacs Lisp programs and not useful by
;; itself.

;; This major mode provides a user interface for applications. The
;; user interface is quite simple, consisting of an input line, a
;; prompt, and some output area, but Lui includes a lot of common
;; options, such as time stamps, filling, colorization, etc.

;; Application programs should create modes derived from lui-mode.

;; The application API consists of:

;; lui-mode
;; lui-set-prompt
;; lui-insert
;; lui-input-function
;; lui-completion-function
;; lui-time-stamp-time
;; lui-time-stamp-zone
;; and the 'lui-fool and 'lui-do-not-track text properties

;;; Code:

(require 'button)
(require 'flyspell)
(require 'help-mode)
(require 'ispell)
(require 'paren)
(require 'ring)
(require 'thingatpt)
(require 'rx)

(require 'tracking)


;;;;;;;;;;;;;;;;;;;;;
;;; Customization ;;;
;;;;;;;;;;;;;;;;;;;;;

(defgroup lui nil
  "The Linewise User Interface."
  :prefix "lui-"
  :group 'applications)

(defcustom lui-scroll-behavior t
  "Set the behavior lui should exhibit for scrolling.

The following values are possible. If in doubt, use post-output.

nil
  Use default Emacs scrolling.

post-command
  Keep the input line at the end of the window if point is
  after the input mark.

post-output
  Keep the input line at the end of the window only after output.

t
  Combine both post-command and post-output.

post-scroll
  Keep the input line at the end of the window on every scroll
  event. Careful, this might interact badly with other functions
  on `window-scroll-functions'.


It would be entirely sensible for Emacs to provide a setting to
do this kind of scrolling by default in a buffer. It seems rather
intuitive and sensible. But as noted on emacs-devel:

  [T]hose who know the code know that it's going to be a pain to
  implement, especially if you want acceptable performance. IOW,
  patches welcome

The full discussion can be found here:

https://lists.gnu.org/archive/html/emacs-devel/2012-10/msg00652.html

These settings are all hacks that try to give the user the choice
between most correct behavior (post-scroll) and most compliant
behavior (post-output)."
  :type '(choice (const :tag "Post Command" t)
                 (const :tag "Post Output" post-output)
                 (const :tag "Post Scroll" post-scroll)
                 (const :tag "Use default scrolling" nil))
  :group 'lui)
(defvaralias 'lui-scroll-to-bottom-p 'lui-scroll-behavior)

(defcustom lui-flyspell-p nil
  "Non-nil if Lui should spell-check your input.
See the function `flyspell-mode' for more information."
  :type 'boolean
  :group 'lui)

(defcustom lui-flyspell-alist nil
  "Alist of buffer dictionaries.

This is a list of mappings from buffers to dictionaries to use
for the function `flyspell-mode'. The appropriate dictionary is
automatically used when Lui is activated in a buffer with a
matching buffer name.

The entries are of the form (REGEXP DICTIONARY), where REGEXP
must match a buffer name, and DICTIONARY specifies an existing
dictionary for the function `flyspell-mode'. See
`ispell-local-dictionary-alist' and `ispell-dictionary-alist' for
a valid list of dictionaries."
  :type 'string
  :group 'lui)

(defcustom lui-highlight-keywords nil
  "A list of keywords to highlight.

This specifies a list of keywords that Lui should highlight. Each
entry is of one of the following forms (similar to
`font-lock-keywords'):

  REGEXP
    Highlight every match in `lui-highlight-face'
  (REGEXP SUBMATCH)
    Highlight the SUBMATCH (a number) in REGEXP in
    `lui-highlight-face'
  (REGEXP FACE)
    Highlight everything matching REGEXP in FACE (a symbol)
  (REGEXP SUBMATCH FACE)
    Highlight the SUBMATCH in REGEXP in FACE

In all of these cases, the FACE can also be a property list which
is then associated with the match.

All matches are run, which means later matches can override
changes by earlier ones."
  :type '(repeat (choice
                  (string :tag "Regular Expression")
                  (list :tag "Submatch"
                        (string :tag "Regular Expression")
                        (integer :tag "Submatch"))
                  (list :tag "Regular Expression in Specific Face"
                        (string :tag "Regular Expression")
                        (face :tag "Face"))
                  (list :tag "Submatch in Specific Face"
                        (string :tag "Regular Expression")
                        (integer :tag "Submatch")
                        (face :tag "Face"))))
  :group 'lui)

(defface lui-strong-face
  '((t (:inherit bold)))
  "Face used for strong markup."
  :group 'lui-irc-colors)

(defface lui-emphasis-face
  '((t (:inherit italic)))
  "Face for emphasis markup."
  :group 'lui-irc-colors)

(defface lui-deleted-face
  '((t (:strike-through t)))
  "Face for deleted messages"
  :group 'lui-irc-colors)

(defcustom lui-formatting-list nil
  "List of enabled formatting types.
Each list item is a list consisting of a regular expression
matching the highlighted text, an integer for the submatch and a
face for highlighting the match."
  :type `(set
          (const :tag "*Strong* text"
                 (,(rx (or bol whitespace)
                       (group "*" (+? (not (any whitespace "*"))) "*")
                       (or eol whitespace))
                  1 lui-strong-face))
          (const :tag "_Emphasized_ text"
                 (,(rx (or bol whitespace)
                       (group "_" (+? (not (any whitespace "_"))) "_")
                       (or eol whitespace))
                  1 lui-emphasis-face)))
  :group 'lui)

(defcustom lui-buttons-list
  `(("`\\([A-Za-z0-9+=*/-]+\\)'" 1
     lui-button-elisp-symbol 1)
    ("\\<debbugs[#:]\\([0-9]+\\)" 0
     "https://debbugs.gnu.org/cgi/bugreport.cgi?bug=%s" 1)
    ("\\<RFC ?\\([0-9]+\\)" 0
     "http://www.ietf.org/rfc/rfc%s.txt" 1)
    ("\\<CVE[- ]\\([0-9]+-[0-9]+\\)" 0
     "https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-%s" 1)
    ("\\<SRFI[- ]?\\([0-9]+\\)" 0
     "http://srfi.schemers.org/srfi-%s/srfi-%s.html" 1 1)
    ("\\<PEP[- ]?\\([0-9]+\\)" 0 lui-button-pep 1)
    ("\\<xkcd[ #]*\\([0-9]+\\)" 0
     "https://xkcd.com/%s" 1)
    ("\\([0-9a-zA-Z_.-]+/[0-9a-zA-Z_.-]+\\)#\\([0-9]+\\)" 0
     "https://github.com/%s/issues/%s" 1 2))
  "The list of buttons to buttonize.
This consists of lists of four elements each:

  (REGEXP SUBMATCH FUNCTION ARG-MATCH...)

Whenever REGEXP is found, SUBMATCH is marked as a button. When
that button is activated, FUNCTION is called with the matches
specified in ARG-MATCHES as its arguments.

If FUNCTION is a string, it is formatted with %s replaced by
the matches in ARG-MATCHES."
  :type '(repeat (list (regexp :tag "Regular expression")
                       (integer :tag "Submatch to buttonize")
                       (function :tag "Function to call for this button")
                       (integer :tag "Submatch to pass as an argument")))
  :group 'lui)

(defcustom lui-button-issue-tracker nil
  "A tracker URL for the current channel.

This will cause simple #123 links to highlight as issue links to
the given repository. Use %s to insert the actual number."
  :type 'string
  :group 'lui)

(defcustom lui-fill-type "    "
  "How Lui should fill its output.
This can be one of the following values:

  A string
      This is used as the fill prefix
  'variable
      The first sequence of non-whitespace characters in the
      output is used as an alignment, and the rest is filled with
      spaces.
  A number
      The first sequence of non-whitespace characters is
      right-aligned at this column, and the rest is filled to
      this column.
  nil
      Turn filling off."
  :type '(choice (string :tag "Fill Prefix")
                 (const :tag "Variable Fill Prefix" variable)
                 (integer :tag "Fill Column")
                 (const :tag "No filling" nil))
  :group 'lui)

(defcustom lui-fill-column 70
  "The column at which Lui should break output.
See `fill-column'."
  :type 'integer
  :group 'lui)

(defcustom lui-fill-remove-face-from-newline t
  "Non-nil when filling should remove faces from newlines.
Faces on a newline extend to the end of the displayed line, which
is often not was is wanted."
  :type 'boolean
  :group 'lui)

(defcustom lui-time-stamp-format "[%H:%M]"
  "The format of time stamps.
See `format-time-string' for a full description of available
formatting directives."
  :type 'string
  :group 'lui)

(defcustom lui-time-stamp-position 'right
  "Where Lui should put time-stamps.
This can be one of the following values:

  A number
      At this column of the first line of output
  'right
      At a column just right to `lui-fill-column'
  'left
      At the left side of the output. The output is thereby moved
      to the right.
  'right-margin
      In the right margin.  You will need to set `right-margin-width'
      in all circe buffers.
  'left-margin
      In the left margin.  You will need to set `left-margin-width'
      in all circe buffers.
  nil
      Do not add any time stamp."
  :type '(choice (const :tag "Right" right)
                 (integer :tag "Column")
                 (const :tag "Left" left)
                 (const :tag "Right Margin" right-margin)
                 (const :tag "Left Margin" left-margin)
                 (const :tag "None" nil))
  :group 'lui)

(defcustom lui-time-stamp-only-when-changed-p t
  "Non-nil if Lui should only add a time stamp when the time changes.
If `lui-time-stamp-position' is 'left, this will still add the
necessary whitespace."
  :type 'boolean
  :group 'lui)

(defcustom lui-read-only-output-p t
  "Non-nil if Lui should make the output read-only.
Switching this off makes copying (by killing) easier for some."
  :type 'boolean
  :group 'lui)

(defcustom lui-max-buffer-size 102400
  "Non-nil if Lui should truncate the buffer if it grows too much.
If the buffer size (in characters) exceeds this number, it is
truncated at the top."
  :type '(choice (const :tag "Never Truncate" nil)
                 (integer :tag "Maximum Buffer Size"))
  :group 'lui)

(defcustom lui-input-ring-size 32
  "The size of the input history of Lui.
This is the size of the input history used by
\\[lui-previous-input] and \\[lui-next-input]."
  :type 'integer
  :group 'lui)

(defcustom lui-mode-hook nil
  "The hook run when Lui is started."
  :type 'hook
  :group 'lui)

(defcustom lui-pre-input-hook nil
  "A hook run before Lui interprets the user input.
It is called with the buffer narrowed to the input line.
Functions can modify the input if they really want to, but the
user won't see the modifications, so that's a bad idea."
  :type 'hook
  :group 'lui)

(defcustom lui-pre-output-hook nil
  "The hook run before output is formatted."
  :type 'hook
  :group 'lui)

(defcustom lui-post-output-hook nil
  "The hook run after output has been formatted."
  :type 'hook
  :group 'lui)

(defface lui-time-stamp-face
  '((t (:foreground "SlateBlue" :weight bold)))
  "Lui mode face used for time stamps."
  :group 'lui)

(defface lui-highlight-face
  ;; Taken from `font-lock-keyword-face'
  '((((class grayscale) (background light)) (:foreground "LightGray" :weight bold))
    (((class grayscale) (background dark)) (:foreground "DimGray" :weight bold))
    (((class color) (background light)) (:foreground "Purple"))
    (((class color) (background dark)) (:foreground "Cyan1"))
    (t (:weight bold)))
  "Lui mode face used for highlighting."
  :group 'lui)

(defface lui-button-face
  '((((class color) (background light)) (:foreground "Purple" :underline t))
    (((class color) (background dark)) (:foreground "Cyan" :underline t))
    (t (:underline t)))
  "Default face used for LUI buttons."
  :group 'lui)


;;;;;;;;;;;;;;;;;;;;;;;;
;;; Client interface ;;;
;;;;;;;;;;;;;;;;;;;;;;;;

(defvar lui-input-function nil
  "The function to be called for Lui input.
This function is called with a single argument, the input
string.")
(make-variable-buffer-local 'lui-input-function)

(defvar lui-completion-function 'completion-at-point
  "A function called to actually do completion.")


;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Private variables ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;

(defvar lui-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map (kbd "RET") 'lui-send-input)
    (define-key map (kbd "TAB") 'lui-next-button-or-complete)
    (define-key map (kbd "<backtab>") 'lui-previous-button)
    (define-key map (kbd "<S-tab>") 'lui-previous-button)
    (define-key map (kbd "M-p") 'lui-previous-input)
    (define-key map (kbd "M-n") 'lui-next-input)
    (define-key map (kbd "C-c C-u") 'lui-kill-to-beginning-of-line)
    (define-key map (kbd "C-c C-i") 'lui-fool-toggle-display)
    map)
  "The key map used in Lui modes.")

(defvar lui-input-marker nil
  "The marker where input should be inserted.")
(make-variable-buffer-local 'lui-input-marker)

(defvar lui-output-marker nil
  "The marker where output should be inserted.
Use `lui-insert' instead of accessing this marker directly.")
(make-variable-buffer-local 'lui-output-marker)

(defvar lui-input-ring nil
  "The input history ring.")
(make-variable-buffer-local 'lui-input-ring)

(defvar lui-input-ring-index nil
  "The index to the current item in the input ring.")
(make-variable-buffer-local 'lui-input-ring-index)


;;;;;;;;;;;;;;
;;; Macros ;;;
;;;;;;;;;;;;;;

(defmacro lui-save-undo-list (&rest body)
  "Run BODY without modifying the undo list."
  (let ((old-marker-sym (make-symbol "old-marker")))
    `(let ((,old-marker-sym (marker-position lui-input-marker))
           (val nil))
       ;; Don't modify the undo list. The undo list is for the user's
       ;; input only.
       (let ((buffer-undo-list t))
         (setq val (progn ,@body)))
       (when (consp buffer-undo-list)
         ;; Not t :-)
         (lui-adjust-undo-list  ,old-marker-sym (- lui-input-marker
                                                   ,old-marker-sym)))
       val)))


;;;;;;;;;;;;;;;;;;
;;; Major Mode ;;;
;;;;;;;;;;;;;;;;;;

(define-derived-mode lui-mode nil "LUI"
  "The Linewise User Interface mode.
This can be used as a user interface for various applications.
Those should define derived modes of this, so this function
should never be called directly.

It can be customized for an application by specifying a
`lui-input-function'."
  (setq lui-input-marker (make-marker)
        lui-output-marker (make-marker)
        lui-input-ring (make-ring lui-input-ring-size)
        lui-input-ring-index nil
        flyspell-generic-check-word-p 'lui-flyspell-check-word-p)
  (set-marker lui-input-marker (point-max))
  (set-marker lui-output-marker (point-max))
  (add-hook 'window-scroll-functions 'lui-scroll-window nil t)
  (add-hook 'post-command-hook 'lui-scroll-post-command)
  (add-hook 'change-major-mode-hook 'lui-change-major-mode nil t)
  (lui-paren-highlighting)
  (lui-time-stamp-enable-filtering)
  (tracking-mode 1)
  (auto-fill-mode 0)
  (when (fboundp 'cursor-intangible-mode)
    (cursor-intangible-mode 1))
  (when lui-flyspell-p
    (require 'flyspell)
    (lui-flyspell-change-dictionary)))

(defun lui-change-major-mode ()
  "Assure that the user really wants to change the major mode.
This is a good value for a buffer-local `change-major-mode-hook'."
  (when (not (y-or-n-p "Really change major mode in a Lui buffer? "))
    (error "User disallowed mode change")))

(defun lui-scroll-window (window _display-start)
  "Scroll the input line to the bottom of the WINDOW.

DISPLAY-START is passed by the hook `window-scroll-functions' and
is ignored.

See `lui-scroll-behavior' for how to customize this."
  (when (and (eq lui-scroll-behavior 'post-scroll)
             window
             (window-live-p window))
    (with-selected-window window
      (when (or (>= (point) lui-input-marker)
                (equal (point-max)
                       (window-end nil t)))
        (let ((resize-mini-windows nil))
          (save-excursion
            (goto-char (point-max))
            (recenter -1)))))))

(defun lui-scroll-post-command ()
  "Scroll the input line to the bottom of the window.

This is called from `post-command-hook'.

See `lui-scroll-behavior' for how to customize this."
  (condition-case err
      (dolist (w (window-list))
        (with-current-buffer (window-buffer w)
          (when (and lui-input-marker
                     (memq lui-scroll-behavior '(t post-command)))
            ;; Code from ERC's erc-goodies.el. I think this was originally
            ;; mine anyhow, not sure though.
            (save-restriction
              (widen)
              (when (>= (point) lui-input-marker)
                (save-excursion
                  (goto-char (point-max))
                  (with-selected-window w
                    (recenter -1))))))))
    (error
     (message "Error in lui-scroll-post-command: %S" err)
     )))

(defun lui-scroll-post-output ()
  "Scroll the input line to the bottom of the window.

This is called when lui output happens.

See `lui-scroll-behavior' for how to customize this."
  (when (memq lui-scroll-behavior '(t post-output))
    (let ((resize-mini-windows nil))
      (dolist (window (get-buffer-window-list (current-buffer) nil t))
        (when (or (>= (point) lui-input-marker)
                  (equal (point-max)
                         (window-end window)))
          (with-selected-window window
            (save-excursion
              (goto-char (point-max))
              (recenter -1))))))))


;;;;;;;;;;;;;
;;; Input ;;;
;;;;;;;;;;;;;

(defun lui-send-input ()
  "Send the current input to the Lui application.
If point is not in the input area, insert a newline."
  (interactive)
  (if (< (point) lui-input-marker)
      (newline)
    (save-restriction
      (narrow-to-region lui-input-marker (point-max))
      (run-hooks 'lui-pre-input-hook))
    (let ((input (buffer-substring lui-input-marker (point-max))))
      (delete-region lui-input-marker (point-max))
      (lui-add-input input)
      (if lui-input-function
          (funcall lui-input-function input)
        (error "No input function specified")))))

(defun lui-add-input (input)
  "Add INPUT as if entered by the user."
  (ring-insert lui-input-ring input)
  (setq lui-input-ring-index nil))


;;;;;;;;;;;;;;;
;;; Buttons ;;;
;;;;;;;;;;;;;;;

(define-button-type 'lui-button
  'supertype 'button
  'follow-link t
  'face 'lui-button-face)

(defun lui-buttonize ()
  "Buttonize the current message."
  (lui-buttonize-urls)
  (lui-buttonize-custom)
  (lui-buttonize-issues))

(defun lui-buttonize-custom ()
  "Add custom buttons to the current message.

This uses `lui-buttons-list'."
  (dolist (entry lui-buttons-list)
    (let ((regex (nth 0 entry))
          (submatch (nth 1 entry))
          (function-or-url (nth 2 entry))
          (arg-matches (nthcdr 3 entry)))
      (goto-char (point-min))
      (while (re-search-forward regex nil t)
        ;; Ensure we're not inserting a button inside a URL button
        (when (not (button-at (match-beginning 0)))
          (let* ((function (if (functionp function-or-url)
                               function-or-url
                             'browse-url))
                 (matches (mapcar (lambda (n)
                                    (match-string-no-properties n))
                                  arg-matches))
                 (arguments (if (functionp function-or-url)
                                matches
                              (list (apply #'format function-or-url
                                           matches)))))
            (make-button (match-beginning submatch)
                         (match-end submatch)
                         'type 'lui-button
                         'action 'lui-button-activate
                         'lui-button-function function
                         'lui-button-arguments arguments)))))))

(defun lui-buttonize-issues ()
  "Buttonize issue references in the current message, if configured."
  (when lui-button-issue-tracker
    (goto-char (point-min))
    (while (re-search-forward "\\(?:^\\|\\W\\)\\(#\\([0-9]+\\)\\)" nil t)
      ;; Ensure we're not inserting a button inside a URL button
      (when (not (button-at (point)))
        (make-button (match-beginning 1)
                     (match-end 1)
                     'type 'lui-button
                     'action 'lui-button-activate
                     'lui-button-function 'browse-url
                     'lui-button-arguments
                     (list (format lui-button-issue-tracker
                                   (match-string 2))))))))

(defun lui-buttonize-urls ()
  "Buttonize URLs in the current message."
  (let ((regex (regexp-opt thing-at-point-uri-schemes)))
    (goto-char (point-min))
    (while (re-search-forward regex nil t)
      (let ((bounds (bounds-of-thing-at-point 'url)))
        (when bounds
          (make-button (car bounds)
                       (cdr bounds)
                       'type 'lui-button
                       'action 'lui-button-activate
                       'lui-button-function 'browse-url
                       'lui-button-arguments
                       (list (buffer-substring-no-properties
                              (car bounds)
                              (cdr bounds)))))))))

(defun lui-button-activate (button)
  "Activate BUTTON.
This calls the function stored in the `lui-button-function'
property with the argument stored in `lui-button-arguments'."
  (apply (button-get button 'lui-button-function)
         (button-get button 'lui-button-arguments)))

(defun lui-next-button-or-complete ()
  "Go to the next button, or complete at point.
When point is in the input line, call `lui-completion-function'.
Otherwise, we move to the next button."
  (interactive)
  (if (>= (point)
          lui-input-marker)
      (funcall lui-completion-function)
    (forward-button 1)))

(defun lui-previous-button ()
  "Go to the previous button."
  (interactive)
  (backward-button 1))

(defun lui-button-elisp-symbol (name)
  "Show the documentation for the symbol named NAME."
  (let ((sym (intern-soft name)))
    (cond
     ((not sym)
      (message "No such symbol %s" name)
      (ding))
     (t
      (help-xref-interned sym)))))

(defun lui-button-pep (number)
  "Browse the PEP NUMBER."
  (browse-url (format "https://www.python.org/dev/peps/pep-%04i"
                      (string-to-number number))))

(defun lui-button-issue (issue)
  "Browse the issue tracker number ISSUE, if configured."
  (if lui-button-issue-tracker
      (browse-url (format lui-button-issue-tracker issue))
    (error "No issue tracker configured, see `lui-button-issue-tracker'")))


;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Input Line Killing ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;

(defun lui-kill-to-beginning-of-line ()
  "Kill the input from point to the beginning of the input."
  (interactive)
  (let* ((beg (point-at-bol))
         (end (point))
         (str (buffer-substring beg end)))
    (delete-region beg end)
    (kill-new str)))


;;;;;;;;;;;;;;;;;;;;;
;;; Input History ;;;
;;;;;;;;;;;;;;;;;;;;;

;; FIXME!
;; These need some better algorithm. They clobber input when it is not
;; in the ring!
(defun lui-previous-input ()
  "Cycle through the input history to the last input."
  (interactive)
  (when (> (ring-length lui-input-ring) 0)
    (if (and lui-input-ring-index
             (= (1- (ring-length lui-input-ring))
                lui-input-ring-index))
        ;; last item - insert a single empty line
        (progn
          (lui-replace-input "")
          (setq lui-input-ring-index nil))
      ;; If any input is left, store it in the input ring
      (when (and (null lui-input-ring-index)
                 (> (point-max) lui-input-marker))
        (ring-insert lui-input-ring
                     (buffer-substring lui-input-marker (point-max)))
        (setq lui-input-ring-index 0))
      ;; Increment the index
      (setq lui-input-ring-index
            (if lui-input-ring-index
                (ring-plus1 lui-input-ring-index (ring-length lui-input-ring))
              0))
      ;; And insert the last input
      (lui-replace-input (ring-ref lui-input-ring lui-input-ring-index))
      (goto-char (point-max)))))

(defun lui-next-input ()
  "Cycle through the input history to the next input."
  (interactive)
  (when (> (ring-length lui-input-ring) 0)
    (if (and lui-input-ring-index
             (= 0 lui-input-ring-index))
        ;; first item - insert a single empty line
        (progn
          (lui-replace-input "")
          (setq lui-input-ring-index nil))
      ;; If any input is left, store it in the input ring
      (when (and (null lui-input-ring-index)
                 (> (point-max) lui-input-marker))
        (ring-insert lui-input-ring
                     (buffer-substring lui-input-marker (point-max)))
        (setq lui-input-ring-index 0))
      ;; Decrement the index
      (setq lui-input-ring-index (ring-minus1 (or lui-input-ring-index 0)
                                              (ring-length lui-input-ring)))
      ;; And insert the next input
      (lui-replace-input (ring-ref lui-input-ring lui-input-ring-index))
      (goto-char (point-max)))))

(defun lui-replace-input (str)
  "Replace input with STR."
  (save-excursion
    (goto-char lui-input-marker)
    (delete-region lui-input-marker (point-max))
    (insert str)))


;;;;;;;;;;;;;
;;; Fools ;;;
;;;;;;;;;;;;;

(defun lui-fools ()
  "Propertize the current narrowing according to foolhardiness.
That is, if any part of it has the text property 'lui-fool set,
make the whole thing invisible."
  (when (text-property-any (point-min)
                           (point-max)
                           'lui-fool t)
    (add-text-properties (point-min)
                         (point-max)
                         '(invisible lui-fool))))

(defun lui-fools-hidden-p ()
  "Return whether fools are currently hidden."
  (if (or (eq t buffer-invisibility-spec)
          (memq 'lui-fool buffer-invisibility-spec))
      t
    nil))

(defun lui-fool-toggle-display ()
  "Display what fools have said."
  (interactive)
  (when (eq buffer-invisibility-spec t)
    (add-to-invisibility-spec 'lui-fool))
  (cond
   ((lui-fools-hidden-p)
    (message "Now showing the gibberish of fools")
    (remove-from-invisibility-spec 'lui-fool))
   (t
    (message "Now hiding fools again *phew*")
    (add-to-invisibility-spec 'lui-fool)))
  ;; For some reason, after this, the display does not always update
  ;; (issue #31). Force an update just in case.
  (force-mode-line-update t))


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Blink Paren and Show Paren Mode ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defun lui-paren-highlighting ()
  "Enable sane parenthesis highlighting in this buffer."
  (set (make-local-variable 'blink-paren-function)
       'lui-blink-paren-function)
  (when (boundp 'show-paren-data-function)
    (set (make-local-variable 'show-paren-data-function)
         'lui-show-paren-data-function)))

(defun lui-blink-paren-function ()
  "Do not blink opening parens outside of the lui input area.

When point is within the lui input area, inserting a closing
parenthesis should only blink parens within the input area, not
outside of it.

This is a suitable value for `blink-paren-function', which see."
  (if (> (point) lui-input-marker)
      (let ((blink-matching-paren-distance (- (point)
                                              lui-input-marker)))
        (blink-matching-open))
    (blink-matching-open)))

(defun lui-show-paren-data-function ()
  "Show parens only within the input area.

When `show-paren-mode' is enabled, and point is in the input
area, parenthesis highlighting should only happen within the
input area, not include the rest of the buffer.

This is a suitable value for `show-paren-data-function', which see."
  (when (fboundp 'show-paren--default)
    (let ((range (show-paren--default)))
      (if (or (< (point) lui-input-marker)
              (not (elt range 2))
              (>= (elt range 2) lui-input-marker))
          range
        nil))))


;;;;;;;;;;;;;;;;
;;; Flyspell ;;;
;;;;;;;;;;;;;;;;

(defun lui-flyspell-change-dictionary (&optional dictionary)
  "*Change flyspell to DICTIONARY.
If DICTIONARY is nil, set a default dictionary according to
`lui-flyspell-alist'.
If it is \"\", disable flyspell."
  (interactive (list (completing-read
                      "Use new dictionary (RET for none, SPC to complete): "
                      (and (fboundp 'ispell-valid-dictionary-list)
                           (mapcar 'list (ispell-valid-dictionary-list)))
                      nil t)))
  (let ((dictionary (or dictionary
                        (lui-find-dictionary (buffer-name)))))
    (when flyspell-mode
      (flyspell-mode 0))
    (when (and dictionary
               (not (equal dictionary "")))
      (ispell-change-dictionary dictionary))
    (flyspell-mode 1)))


(defun lui-find-dictionary (buffer-name)
  "Return a dictionary appropriate for BUFFER-NAME."
  (let ((lis lui-flyspell-alist)
        (result nil))
    (while lis
      (if (string-match (caar lis) buffer-name)
          (setq result (cadr (car lis))
                lis nil)
         (setq lis (cdr lis))))
    result))

(defun lui-flyspell-check-word-p ()
  "Return non-nil when flyspell should verify at this position.
This is the value of Lui for `flyspell-generic-check-word-p'."
  (>= (point)
      lui-input-marker))


;;;;;;;;;;;;;;
;;; Output ;;;
;;;;;;;;;;;;;;

(defvar lui-message-id 0
  "Unique id for each message.
Used to allow navigation between messages and editing and
deleting.")
(make-variable-buffer-local 'lui-message-id)

(defvar lui-internal-text-properties '(lui-formatted-time-stamp
                                       lui-time-stamp-last
                                       lui-raw-text
                                       lui-message-id
                                       lui-saved-text-properties)
  "Text properties used internally by lui.

These are always kept when replacing messages.")

(defun lui-insert (str &optional not-tracked-p)
  "Insert STR into the current Lui buffer.

If NOT-TRACKED-P is given, this insertion won't trigger tracking
of the buffer."
  (if not-tracked-p
      (lui-insert-with-text-properties str 'not-tracked-p t)
    (lui-insert-with-text-properties str)))

(defun lui-plist-keys (plist)
  "Get the keys from PLIST.

PLIST should be a flat list with keys and values alternating,
like used for setting and getting text properties."
  (let ((key t) result)
    (dolist (item plist (reverse result))
      (when key
        (push item result))
      (setq key (not key)))))

(defun lui-insert-with-text-properties (str &rest text-properties)
  "Insert STR into the current Lui buffer.

TEXT-PROPERTIES is a property list containing text properties to
add to the inserted message."
  (let ((not-tracked-p (plist-get text-properties 'not-tracked-p))
        (saved-text-properties (append (lui-plist-keys text-properties)
                                       lui-internal-text-properties)))
    (lui-save-undo-list
     (save-excursion
       (save-restriction
         (let ((inhibit-read-only t)
               (inhibit-point-motion-hooks t))
           (widen)
           (goto-char lui-output-marker)
           (let ((beg (point))
                 (end nil))
             (insert str "\n")
             (setq end (point))
             (set-marker lui-output-marker (point))
             (narrow-to-region beg end))
           (goto-char (point-min))
           (add-text-properties (point-min)
                                (point-max)
                                `(lui-raw-text ,str))
           (run-hooks 'lui-pre-output-hook)
           (lui-apply-formatting)
           (lui-highlight-keywords)
           (lui-buttonize)
           (lui-fill)
           (lui-time-stamp
            (plist-get text-properties 'lui-formatted-time-stamp))
           (goto-char (point-min))
           (add-text-properties
            (point-min) (point-max)
            (plist-put text-properties 'lui-message-id lui-message-id))
           (setq lui-message-id (1+ lui-message-id))
           (run-hooks 'lui-post-output-hook)
           (lui-fools)
           (goto-char (point-min))
           (add-text-properties
            (point-min) (point-max)
            `(lui-saved-text-properties ,saved-text-properties))
           (let ((faces (lui-faces-in-region (point-min)
                                             (point-max)))
                 (foolish (text-property-any (point-min)
                                             (point-max)
                                             'lui-fool t))
                 (not-tracked-p
                  (or not-tracked-p
                      (text-property-any (point-min)
                                         (point-max)
                                         'lui-do-not-track t))))
             (widen)
             (lui-truncate)
             (lui-read-only)
             (when (and (not not-tracked-p)
                        (not foolish))
               (tracking-add-buffer (current-buffer)
                                    faces)))
           (lui-scroll-post-output)))))))

(defun lui--adjust-p (pos old)
  (and (numberp pos) (>= (abs pos) old)))

(defun lui--new-pos (pos shift)
  (* (if (< pos 0) -1 1) (+ (abs pos) shift)))

(defun lui-adjust-undo-list (old-begin shift)
  ;; Translate buffer positions in buffer-undo-list by SHIFT.
  (unless (or (zerop shift) (atom buffer-undo-list))
    (let ((list buffer-undo-list) elt)
      (while list
        (setq elt (car list))
        (cond ((integerp elt)           ; POSITION
               (if (lui--adjust-p elt old-begin)
                   (setf (car list) (lui--new-pos elt shift))))
              ((or (atom elt)           ; nil, EXTENT
                   (markerp (car elt))) ; (MARKER . DISTANCE)
               nil)
              ((integerp (car elt))     ; (BEGIN . END)
               (if (lui--adjust-p (car elt) old-begin)
                   (setf (car elt) (lui--new-pos (car elt) shift)))
               (if (lui--adjust-p (cdr elt) old-begin)
                   (setf (cdr elt) (lui--new-pos (cdr elt) shift))))
              ((stringp (car elt))      ; (TEXT . POSITION)
               (if (lui--adjust-p (cdr elt) old-begin)
                   (setf (cdr elt) (lui--new-pos (cdr elt) shift))))
              ((null (car elt))         ; (nil PROPERTY VALUE BEG . END)
               (let ((cons (nthcdr 3 elt)))
                 (if (lui--adjust-p (car cons) old-begin)
                     (setf (car cons) (lui--new-pos (car cons) shift)))
                 (if (lui--adjust-p (cdr cons) old-begin)
                     (setf (cdr cons) (lui--new-pos (cdr cons) shift)))))
              ((and (featurep 'xemacs)
                    (extentp (car elt))) ; (EXTENT START END)
               (if (lui--adjust-p (nth 1 elt) old-begin)
                     (setf (nth 1 elt) (lui--new-pos (nth 1 elt) shift)))
                 (if (lui--adjust-p (nth 2 elt) old-begin)
                     (setf (nth 2 elt) (lui--new-pos (nth 2 elt) shift)))))
        (setq list (cdr list))))))

(defvar lui-prompt-map
  (let ((map (make-sparse-keymap)))
    (define-key map (kbd "<end>") 'lui-prompt-end-of-line)
    (define-key map (kbd "C-e") 'lui-prompt-end-of-line)
    map)
  "Keymap for Lui prompts.
Since \\[end-of-line] can't move out of fields, this DTRT for an
unexpecting user.")

(defun lui-set-prompt (prompt)
  "Set PROMPT as the current Lui prompt."
  (let ((inhibit-read-only t))
    (lui-save-undo-list
     (save-excursion
       (goto-char lui-output-marker)
       (insert prompt)
       (if (> lui-input-marker (point))
           (delete-region (point) lui-input-marker)
         (set-marker lui-input-marker (point)))
       (add-text-properties lui-output-marker lui-input-marker
                            `(read-only t
                                        rear-nonsticky t
                                        field lui-prompt
                                        keymap ,lui-prompt-map
                                        front-sticky t
                                        ))))))

(defun lui-prompt-end-of-line (&optional _N)
  "Move past the prompt, and then to the end of the line.
This uses `end-of-line'.

The argument N is ignored."
  (interactive "p")
  (goto-char lui-input-marker)
  (call-interactively 'end-of-line))

(defun lui-faces-in-region (beg end)
  "Return a face that describes the region between BEG and END."
  (goto-char beg)
  (let ((faces nil))
    (while (not (= (point) end))
      (let ((face (get-text-property (point) 'face)))
        (dolist (face (if (consp face)
                          face
                        (list face)))
          (when (and face
                     (facep face)
                     (face-differs-from-default-p face))
            (push face faces)))
        (goto-char (next-single-property-change (point) 'face
                                                nil end))))
    faces))



;;;;;;;;;;;;;;;;;;;;
;;; Highlighting ;;;
;;;;;;;;;;;;;;;;;;;;

(defun lui-highlight-keywords ()
  "Highlight the entries in the variable `lui-highlight-keywords'.

This is called automatically when new text is inserted."
  (let ((regex (lambda (entry)
                 (if (stringp entry)
                     entry
                   (car entry))))
        (submatch (lambda (entry)
                    (if (and (consp entry)
                             (numberp (cadr entry)))
                        (cadr entry)
                      0)))
        (properties (lambda (entry)
                      (let ((face (cond
                                   ;; REGEXP
                                   ((stringp entry)
                                    'lui-highlight-face)
                                   ;; (REGEXP SUBMATCH)
                                   ((and (numberp (cadr entry))
                                         (null (cddr entry)))
                                    'lui-highlight-face)
                                   ;; (REGEXP FACE)
                                   ((null (cddr entry))
                                    (cadr entry))
                                   ;; (REGEXP SUBMATCH FACE)
                                   (t
                                    (nth 2 entry)))))
                        (if (facep face)
                            `(face ,face)
                          face)))))
    (dolist (entry lui-highlight-keywords)
      (goto-char (point-min))
      (while (re-search-forward (funcall regex entry) nil t)
        (let* ((exp (funcall submatch entry))
               (beg (match-beginning exp))
               (end (match-end exp)))
          (when (not (text-property-any beg end 'lui-highlight-fontified-p t))
            (add-text-properties beg end
                                 (append (funcall properties entry)
                                         '(lui-highlight-fontified-p t)))))))))

(defun lui-apply-formatting ()
  "Highlight the entries in `lui-formatting-list'."
  (dolist (entry lui-formatting-list)
    (goto-char (point-min))
    (let ((re (car entry))
          (subgroup (cadr entry))
          (face (nth 2 entry)))
      (while (re-search-forward re nil t)
        (when face
          (add-face-text-property (match-beginning subgroup) (match-end subgroup)
                                  face nil (current-buffer)))))))


;;;;;;;;;;;;;;;
;;; Filling ;;;
;;;;;;;;;;;;;;;

(defun lui-fill ()
  "Fill the text in the buffer.
This is called automatically when new text is inserted. See
`lui-fill-type' and `lui-fill-column' on how to customize this
function."
  (cond
   ((stringp lui-fill-type)
    (let ((fill-prefix lui-fill-type)
          (fill-column (or lui-fill-column
                           fill-column)))
      (fill-region (point-min) (point-max)
                   nil t)))
   ((eq lui-fill-type 'variable)
    (let ((fill-prefix (save-excursion
                         (goto-char (point-min))
                         (let ((beg (point)))
                           (re-search-forward "\\s-" nil t)
                           (make-string (- (point) beg) ? ))))
          (fill-column (or lui-fill-column
                           fill-column)))
      (fill-region (point-min) (point-max)
                   nil t)))
   ((numberp lui-fill-type)
    (let ((right-end (save-excursion
                       (goto-char (point-min))
                       (re-search-forward "\\s-" nil t)
                       (- (point)
                          (point-at-bol)))))
      (goto-char (point-min))
      (when (< right-end lui-fill-type)
        (insert (make-string (- lui-fill-type
                                right-end)
                             ? )))
      (let ((fill-prefix (make-string lui-fill-type ? ))
            (fill-column (or lui-fill-column
                             fill-column)))
        (fill-region (point-min) (point-max)
                     nil t)))))
  (when lui-fill-remove-face-from-newline
    (goto-char (point-min))
    (while (re-search-forward "\n" nil t)
      (put-text-property (match-beginning 0)
                         (match-end 0)
                         'face
                         nil))))


;;;;;;;;;;;;;;;;;;;
;;; Time Stamps ;;;
;;;;;;;;;;;;;;;;;;;

(defvar lui-time-stamp-last nil
  "The last time stamp.")
(make-variable-buffer-local 'lui-time-stamp-last)

(defvar lui-time-stamp-time nil
  "A custom time to use as the time stamp for `lui-insert'.

This variable should be let-bound when you wish to provide a
custom time to be printed by `lui-time-stamp'.  If this variable
is nil the current time is used.  See the TIME argument to
`format-time-string' for more information.")

(defvar lui-time-stamp-zone nil
  "A custom timezone to use for the time stamp for `lui-insert'.

This variable should be let-bound when you wish to provide a
custom time zone when printing the time stamp with
`lui-time-stamp'.  If this variable is nil local time is used.
See the ZONE argument to `format-time-string' for more
information.")

(defun lui-time-stamp (&optional text)
  "Add a time stamp to the current buffer.

If TEXT is specified, use that instead of formatting a new time stamp."
  (let ((ts (or text
                (format-time-string lui-time-stamp-format
                                    lui-time-stamp-time
                                    lui-time-stamp-zone))))
    (cond
     ;; Time stamps right
     ((or (numberp lui-time-stamp-position)
          (eq lui-time-stamp-position 'right))
      (when (or (not lui-time-stamp-only-when-changed-p)
                (not lui-time-stamp-last)
                (not (string= ts lui-time-stamp-last)))
        (goto-char (point-min))
        (goto-char (point-at-eol))
        (let* ((curcol (current-column))
               (col (if (numberp lui-time-stamp-position)
                        lui-time-stamp-position
                      (+ 2 (or lui-fill-column
                               fill-column
                               (point)))))
               (indent (if (> col curcol)
                           (- col curcol)
                         1))
               (ts-string (propertize
                           (concat (make-string indent ?\s)
                                   (propertize
                                    ts
                                    'face 'lui-time-stamp-face))
                           'lui-time-stamp t))
               (start (point)))
          (insert ts-string)
          (add-text-properties start (1+ (point)) '(intangible t))
          (add-text-properties (1+ start) (point) '(cursor-intangible t)))))
     ;; Time stamps left
     ((eq lui-time-stamp-position 'left)
      (let ((indent-string (propertize (make-string (length ts) ?\s)
                                       'lui-time-stamp t)))
        (goto-char (point-min))
        (cond
         ;; Time stamp
         ((or (not lui-time-stamp-only-when-changed-p)
              (not lui-time-stamp-last)
              (not (string= ts lui-time-stamp-last)))
          (insert (propertize ts
                              'face 'lui-time-stamp-face
                              'lui-time-stamp t)))
         ;; Just indentation
         (t
          (insert indent-string)))
        (forward-line 1)
        (while (< (point) (point-max))
          (insert indent-string)
          (forward-line 1))))
     ;; Time stamps in margin
     ((or (eq lui-time-stamp-position 'right-margin)
          (eq lui-time-stamp-position 'left-margin))
      (when (or (not lui-time-stamp-only-when-changed-p)
                (not lui-time-stamp-last)
                (not (string= ts lui-time-stamp-last)))
        (goto-char (point-min))
        (when lui-fill-type
          (goto-char (point-at-eol)))
        (let* ((ts (propertize ts 'face 'lui-time-stamp-face))
               (ts-margin (propertize
                           " "
                           'display `((margin ,lui-time-stamp-position)
                                      ,ts)
                           'lui-time-stamp t)))
          (insert ts-margin)))))
    (add-text-properties (point-min) (point-max)
                         `(lui-formatted-time-stamp ,ts
                           lui-time-stamp-last ,lui-time-stamp-last))
    (setq lui-time-stamp-last ts)))

(defun lui-time-stamp-enable-filtering ()
  "Enable filtering of timestamps from copied text."
  (set (make-local-variable 'filter-buffer-substring-functions)
       '(lui-filter-buffer-time-stamps)))

(defun lui-filter-buffer-time-stamps (fun beg end delete)
  "Filter text from copied strings.

This is meant for the variable `filter-buffer-substring-functions',
which see for an explanation of the argument FUN, BEG, END and
DELETE."
  (let ((string (funcall fun beg end delete))
        (inhibit-point-motion-hooks t)
        (inhibit-read-only t)
        ;; Emacs 24.4, 24.5
        deactivate-mark)
    (with-temp-buffer
      (insert string)
      (let ((start (text-property-any (point-min)
                                      (point-max)
                                      'lui-time-stamp t)))
        (while start
          (let ((end (next-single-property-change start 'lui-time-stamp
                                                  nil (point-max))))
            (delete-region start end)
            (setq start (text-property-any (point-min) (point-max)
                                           'lui-time-stamp t))))
        (buffer-string)))))

(defun lui-time-stamp-buffer-substring (buffer-string)
  "Filter text from copied strings.

This is meant for the variable `buffer-substring-filters',
which see for an explanation of the argument BUFFER-STRING."
  (lui-filter-buffer-time-stamps (lambda (_beg _end _delete)
                                  buffer-string)
                                nil nil nil))


;;;;;;;;;;;;;;;;;;
;;; Truncating ;;;
;;;;;;;;;;;;;;;;;;

(defun lui-truncate ()
  "Truncate the current buffer if it exceeds `lui-max-buffer-size'."
  (when (and lui-max-buffer-size
             (> (point-max)
                lui-max-buffer-size))
    (goto-char (- (point-max)
                  lui-max-buffer-size))
    (forward-line 0)
    (let ((inhibit-read-only t))
      (delete-region (point-min) (point)))))


;;;;;;;;;;;;;;;;;
;;; Read-Only ;;;
;;;;;;;;;;;;;;;;;

(defun lui-read-only ()
  "Make the current output read-only if `lui-read-only-output-p' is non-nil."
  (when lui-read-only-output-p
    (add-text-properties (point-min) lui-output-marker
                         '(read-only t
                           front-sticky t))))


;;;;;;;;;;;;;;;;;;
;;; Navigation ;;;
;;;;;;;;;;;;;;;;;;

(defun lui-at-message-p ()
  "Check if point is on a message."
  (get-text-property (point) 'lui-message-id))

(defun lui-beginning-of-message-p ()
  "Check if point is at the beginning of a message."
  (or (= (point) (point-min))
      (not (equal (get-text-property (point) 'lui-message-id)
                  (get-text-property (1- (point)) 'lui-message-id)))))

(defun lui-beginning-of-message ()
  "Move point to the beginning of the message at point."
  (goto-char (previous-single-property-change (point) 'lui-message-id)))

(defun lui-forward-message ()
  "Move point to the next message in the buffer and return point.
If there is no next message, move to the end of the buffer instead."
  (let ((current-id (get-text-property (point) 'lui-message-id))
        (next-point
         (next-single-property-change (point) 'lui-message-id)))
    (if (not next-point)
        (goto-char (point-max))
      (let ((message-id
             (get-text-property next-point 'lui-message-id)))
        (goto-char next-point)
        (when (or (not (or current-id message-id))
                  (and current-id (not message-id))
                  (and current-id message-id
                       (= current-id message-id)))
          (lui-forward-message))))
    (point)))

(defun lui-backward-message ()
  "Move point to the previous message in the buffer and return point.
If there is no previous message, move to the beginning of the
buffer instead."
  (let ((current-id (get-text-property (point) 'lui-message-id))
        (prev-point
         (previous-single-property-change (point) 'lui-message-id)))
    (if (not prev-point)
        (goto-char (point-min))
      (let ((message-id
             (get-text-property prev-point 'lui-message-id)))
        (goto-char prev-point)
        (when (or (not (or current-id message-id))
                  (and current-id (not message-id))
                  (and current-id message-id
                       (= current-id message-id)))
          (lui-backward-message))))
    (point)))


;;;;;;;;;;;;;;;
;;; Editing ;;;
;;;;;;;;;;;;;;;

(defun lui-recover-output-marker ()
  "Reset the output marker to just before the lui prompt."
  (let ((input-position (marker-position lui-input-marker)))
    (set-marker lui-output-marker
                (field-beginning (1- input-position)))))

(defun lui-build-plist (keys)
  "Build a plist with KEYS taken from current text properties."
  (let (result)
    (dolist (key keys result)
      (let ((value (get-text-property (point) key)))
        (when value
          (setq result (plist-put result key value)))))))

(defun lui-replace-message (new-message)
  "Replace the message at point with NEW-MESSAGE."
  (unless (lui-at-message-p)
    (error "Point is not on a message"))
  (unless (lui-beginning-of-message-p)
    (lui-beginning-of-message))
  (let* ((saved-text-properties
          (get-text-property (point) 'lui-saved-text-properties))
         (text-properties (lui-build-plist saved-text-properties))
         (inhibit-read-only t)
         (lui-time-stamp-last
          (get-text-property (point) 'lui-time-stamp-last))
         (lui-message-id
          (get-text-property (point) 'lui-message-id)))
    (unwind-protect
        (progn
          (setq lui-output-marker (point-marker))
          (delete-region (point)
                         (next-single-property-change (point) 'lui-message-id))
          (apply #'lui-insert-with-text-properties new-message
                 (plist-put text-properties 'not-tracked-p t)))
      (lui-recover-output-marker))))

(defun lui-replace (new-message predicate)
  "Replace a message with NEW-MESSAGE.

PREDICATE should be a function that returns a non-nil value for
the message that should be replaced."
  (save-excursion
    (goto-char (point-max))
    (while (> (lui-backward-message) (point-min))
      (when (funcall predicate)
        (lui-replace-message new-message)))))

(defun lui-delete-message ()
  "Delete the message at point."
  (unless (lui-at-message-p)
    (error "Point is not on a message"))
  (unless (lui-beginning-of-message-p)
    (lui-beginning-of-message))
  (let ((inhibit-read-only t))
    (add-text-properties (point)
                         (next-single-property-change (point) 'lui-message-id)
                         '(face lui-deleted-face))))

(defun lui-delete (predicate)
  "Delete a message.

PREDICATE should be a function that returns a non-nil value for
the message that should be replaced."
  (save-excursion
    (goto-char (point-max))
    (while (> (lui-backward-message) (point-min))
      (when (funcall predicate)
        (lui-delete-message)))))


(provide 'lui)
;;; lui.el ends here