File size: 140,131 Bytes
8c763fb
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Management.Automation.Language;
using System.Reflection;
using System.Text;
using System.Text.RegularExpressions;
using System.Management.Automation.Subsystem;
using System.Management.Automation.Subsystem.DSC;

namespace System.Management.Automation
{
    internal class CompletionContext
    {
        internal List<Ast> RelatedAsts { get; set; }

        // Only one of TokenAtCursor or TokenBeforeCursor is set
        // This is how we can tell if we're trying to complete part of something (like a member)
        // or complete an argument, where TokenBeforeCursor could be a parameter name.
        internal Token TokenAtCursor { get; set; }

        internal Token TokenBeforeCursor { get; set; }

        internal IScriptPosition CursorPosition { get; set; }

        internal PowerShellExecutionHelper Helper { get; set; }

        internal Hashtable Options { get; set; }

        internal Dictionary<string, ScriptBlock> CustomArgumentCompleters { get; set; }

        internal Dictionary<string, ScriptBlock> NativeArgumentCompleters { get; set; }

        internal string WordToComplete { get; set; }

        internal int ReplacementIndex { get; set; }

        internal int ReplacementLength { get; set; }

        internal ExecutionContext ExecutionContext { get; set; }

        internal PseudoBindingInfo PseudoBindingInfo { get; set; }

        internal TypeInferenceContext TypeInferenceContext { get; set; }

        internal bool GetOption(string option, bool @default)
        {
            if (Options == null || !Options.ContainsKey(option))
            {
                return @default;
            }

            return LanguagePrimitives.ConvertTo<bool>(Options[option]);
        }
    }

    internal class CompletionAnalysis
    {
        private readonly Ast _ast;
        private readonly Token[] _tokens;
        private readonly IScriptPosition _cursorPosition;
        private readonly Hashtable _options;

        internal CompletionAnalysis(Ast ast, Token[] tokens, IScriptPosition cursorPosition, Hashtable options)
        {
            _ast = ast;
            _tokens = tokens;
            _cursorPosition = cursorPosition;
            _options = options;
        }

        private static bool IsInterestingToken(Token token)
        {
            return token.Kind != TokenKind.NewLine && token.Kind != TokenKind.EndOfInput;
        }

        private static bool IsCursorWithinOrJustAfterExtent(IScriptPosition cursor, IScriptExtent extent)
        {
            return cursor.Offset > extent.StartOffset && cursor.Offset <= extent.EndOffset;
        }

        private static bool IsCursorRightAfterExtent(IScriptPosition cursor, IScriptExtent extent)
        {
            return cursor.Offset == extent.EndOffset;
        }

        private static bool IsCursorAfterExtentAndInTheSameLine(IScriptPosition cursor, IScriptExtent extent)
        {
            return cursor.Offset >= extent.EndOffset && extent.EndLineNumber == cursor.LineNumber;
        }

        private static bool IsCursorBeforeExtent(IScriptPosition cursor, IScriptExtent extent)
        {
            return cursor.Offset < extent.StartOffset;
        }

        private static bool IsCursorAfterExtent(IScriptPosition cursor, IScriptExtent extent)
        {
            return extent.EndOffset < cursor.Offset;
        }

        private static bool IsCursorOutsideOfExtent(IScriptPosition cursor, IScriptExtent extent)
        {
            return cursor.Offset < extent.StartOffset || cursor.Offset > extent.EndOffset;
        }

        internal readonly struct AstAnalysisContext
        {
            internal AstAnalysisContext(Token tokenAtCursor, Token tokenBeforeCursor, List<Ast> relatedAsts, int replacementIndex)
            {
                TokenAtCursor = tokenAtCursor;
                TokenBeforeCursor = tokenBeforeCursor;
                RelatedAsts = relatedAsts;
                ReplacementIndex = replacementIndex;
            }

            internal readonly Token TokenAtCursor;
            internal readonly Token TokenBeforeCursor;
            internal readonly List<Ast> RelatedAsts;
            internal readonly int ReplacementIndex;
        }

        internal static AstAnalysisContext ExtractAstContext(Ast inputAst, Token[] inputTokens, IScriptPosition cursor)
        {
            bool adjustLineAndColumn = false;
            IScriptPosition positionForAstSearch = cursor;

            Token tokenBeforeCursor = null;
            Token tokenAtCursor = InterstingTokenAtCursorOrDefault(inputTokens, cursor);
            if (tokenAtCursor == null)
            {
                tokenBeforeCursor = InterstingTokenBeforeCursorOrDefault(inputTokens, cursor);
                if (tokenBeforeCursor != null)
                {
                    positionForAstSearch = tokenBeforeCursor.Extent.EndScriptPosition;
                    adjustLineAndColumn = true;
                }
            }
            else
            {
                var stringExpandableToken = tokenAtCursor as StringExpandableToken;
                if (stringExpandableToken?.NestedTokens != null)
                {
                    tokenAtCursor = InterstingTokenAtCursorOrDefault(stringExpandableToken.NestedTokens, cursor) ?? stringExpandableToken;
                }
            }

            int replacementIndex = adjustLineAndColumn ? cursor.Offset : 0;
            List<Ast> relatedAsts = AstSearcher.FindAll(
                inputAst,
                ast => IsCursorWithinOrJustAfterExtent(positionForAstSearch, ast.Extent),
                searchNestedScriptBlocks: true).ToList();

            if (relatedAsts.Count == 0)
            {
                relatedAsts.Add(inputAst);
            }

            // If the last ast is an unnamed block that starts with "param" the cursor is inside a param block.
            // To avoid adding special handling to all the completers that look at the last ast, we remove it here because it's not useful for completion.
            if (relatedAsts[^1].Extent.Text.StartsWith("param", StringComparison.OrdinalIgnoreCase)
                && relatedAsts[^1] is NamedBlockAst namedBlock && namedBlock.Unnamed)
            {
                relatedAsts.RemoveAt(relatedAsts.Count - 1);
            }

            Diagnostics.Assert(tokenAtCursor == null || tokenBeforeCursor == null, "Only one of these tokens can be non-null");

            return new AstAnalysisContext(tokenAtCursor, tokenBeforeCursor, relatedAsts, replacementIndex);
        }

        internal CompletionContext CreateCompletionContext(PowerShell powerShell)
        {
            var typeInferenceContext = new TypeInferenceContext(powerShell);
            return InitializeCompletionContext(typeInferenceContext);
        }

        internal CompletionContext CreateCompletionContext(TypeInferenceContext typeInferenceContext)
        {
            return InitializeCompletionContext(typeInferenceContext);
        }

        private CompletionContext InitializeCompletionContext(TypeInferenceContext typeInferenceContext)
        {
            var astContext = ExtractAstContext(_ast, _tokens, _cursorPosition);

            typeInferenceContext.CurrentTypeDefinitionAst ??= Ast.GetAncestorTypeDefinitionAst(astContext.RelatedAsts.Last());

            ExecutionContext executionContext = typeInferenceContext.ExecutionContext;

            return new CompletionContext
            {
                Options = _options,
                CursorPosition = _cursorPosition,
                TokenAtCursor = astContext.TokenAtCursor,
                TokenBeforeCursor = astContext.TokenBeforeCursor,
                RelatedAsts = astContext.RelatedAsts,
                ReplacementIndex = astContext.ReplacementIndex,
                ExecutionContext = executionContext,
                TypeInferenceContext = typeInferenceContext,
                Helper = typeInferenceContext.Helper,
                CustomArgumentCompleters = executionContext.CustomArgumentCompleters,
                NativeArgumentCompleters = executionContext.NativeArgumentCompleters,
            };
        }

        private static Token InterstingTokenAtCursorOrDefault(IReadOnlyList<Token> tokens, IScriptPosition cursorPosition)
        {
            for (int i = tokens.Count - 1; i >= 0; --i)
            {
                Token token = tokens[i];
                if (IsCursorWithinOrJustAfterExtent(cursorPosition, token.Extent) && IsInterestingToken(token))
                {
                    return token;
                }
            }

            return null;
        }

        private static Token InterstingTokenBeforeCursorOrDefault(IReadOnlyList<Token> tokens, IScriptPosition cursorPosition)
        {
            for (int i = tokens.Count - 1; i >= 0; --i)
            {
                Token token = tokens[i];
                if (IsCursorAfterExtent(cursorPosition, token.Extent) && IsInterestingToken(token))
                {
                    return token;
                }
            }

            return null;
        }

        private static Ast GetLastAstAtCursor(ScriptBlockAst scriptBlockAst, IScriptPosition cursorPosition)
        {
            var asts = AstSearcher.FindAll(scriptBlockAst, ast => IsCursorRightAfterExtent(cursorPosition, ast.Extent), searchNestedScriptBlocks: true);
            return asts.LastOrDefault();
        }

        #region Special Cases

        /// <summary>
        /// Check if we should complete file names for "switch -file"
        /// </summary>
        private static bool CompleteAgainstSwitchFile(Ast lastAst, Token tokenBeforeCursor)
        {
            Tuple<Token, Ast> fileConditionTuple;

            if (lastAst is ErrorStatementAst errorStatement && errorStatement.Flags is not null && errorStatement.Kind is not null && tokenBeforeCursor is not null &&
                errorStatement.Kind.Kind.Equals(TokenKind.Switch) && errorStatement.Flags.TryGetValue("file", out fileConditionTuple))
            {
                // Handle "switch -file <tab>"
                return fileConditionTuple.Item1.Extent.EndOffset == tokenBeforeCursor.Extent.EndOffset;
            }

            if (lastAst.Parent is CommandExpressionAst)
            {
                // Handle "switch -file m<tab>" or "switch -file *.ps1<tab>"
                if (lastAst.Parent.Parent is not PipelineAst pipeline)
                {
                    return false;
                }

                if (pipeline.Parent is not ErrorStatementAst parentErrorStatement || parentErrorStatement.Kind is null || parentErrorStatement.Flags is null)
                {
                    return false;
                }

                return (parentErrorStatement.Kind.Kind.Equals(TokenKind.Switch) &&
                        parentErrorStatement.Flags.TryGetValue("file", out fileConditionTuple) && fileConditionTuple.Item2 == pipeline);
            }

            return false;
        }

        /// <summary>
        /// Check if we should complete parameter names for switch cases on $PSBoundParameters.Keys
        /// </summary>
        private static List<CompletionResult> CompleteAgainstSwitchCaseCondition(CompletionContext completionContext)
        {
            var lastAst = completionContext.RelatedAsts.Last();

            PipelineAst conditionPipeline = null;
            Ast switchAst = null;

            // Check if we're in a switch statement (complete) or error statement (incomplete switch)
            if (lastAst.Parent is SwitchStatementAst switchStatementAst)
            {
                // Verify that the lastAst is one of the clause conditions (not in the body)
                bool isClauseCondition = switchStatementAst.Clauses.Any(clause => clause.Item1 == lastAst);

                if (!isClauseCondition)
                {
                    return null;
                }

                conditionPipeline = switchStatementAst.Condition as PipelineAst;
                switchAst = switchStatementAst;
            }
            else
            {
                // Check for incomplete switch parsed as ErrorStatementAst
                if (lastAst.Parent is not ErrorStatementAst errorStatementAst || errorStatementAst.Kind is null ||
                    errorStatementAst.Kind.Kind != TokenKind.Switch)
                {
                    return null;
                }

                // For ErrorStatementAst, the case value is in Bodies, condition is in Conditions
                bool isInBodies = errorStatementAst.Bodies != null && errorStatementAst.Bodies.Any(body => body == lastAst);

                if (!isInBodies)
                {
                    return null;
                }

                // Get the condition from ErrorStatementAst.Conditions
                if (errorStatementAst.Conditions != null && errorStatementAst.Conditions.Count > 0)
                {
                    conditionPipeline = errorStatementAst.Conditions[0] as PipelineAst;
                }
                switchAst = errorStatementAst;
            }

            if (conditionPipeline == null || conditionPipeline.PipelineElements.Count != 1)
            {
                return null;
            }

            if (conditionPipeline.PipelineElements[0] is not CommandExpressionAst commandExpressionAst)
            {
                return null;
            }

            // Check if the expression is a member access on $PSBoundParameters.Keys
            if (commandExpressionAst.Expression is not MemberExpressionAst memberExpressionAst)
            {
                return null;
            }

            // Check if the target is $PSBoundParameters
            if (memberExpressionAst.Expression is not VariableExpressionAst variableExpressionAst ||
                !variableExpressionAst.VariablePath.UserPath.Equals("PSBoundParameters", StringComparison.OrdinalIgnoreCase))
            {
                return null;
            }

            // Check if the member is "Keys"
            if (memberExpressionAst.Member is not StringConstantExpressionAst memberNameAst ||
                !memberNameAst.Value.Equals("Keys", StringComparison.OrdinalIgnoreCase))
            {
                return null;
            }

            // Find the nearest param block by traversing up the AST
            var paramBlockAst = FindNearestParamBlock(switchAst.Parent);

            if (paramBlockAst == null || paramBlockAst.Parameters.Count == 0)
            {
                return null;
            }

            // Generate completion results from parameter names
            var wordToComplete = completionContext.WordToComplete ?? string.Empty;
            return CreateParameterCompletionResults(paramBlockAst, wordToComplete);
        }

        /// <summary>
        /// Check if we should complete parameter names for $PSBoundParameters access patterns
        /// Supports: $PSBoundParameters.ContainsKey('...'), $PSBoundParameters['...'], $PSBoundParameters.Remove('...')
        /// </summary>
        private static List<CompletionResult> CompleteAgainstPSBoundParametersAccess(CompletionContext completionContext)
        {
            var lastAst = completionContext.RelatedAsts.Last();

            // Must be a string constant
            if (lastAst is not StringConstantExpressionAst stringAst)
            {
                return null;
            }

            ExpressionAst targetAst = null;

            // Check for method invocation: $PSBoundParameters.ContainsKey('...') or $PSBoundParameters.Remove('...')
            if (lastAst.Parent is InvokeMemberExpressionAst invokeMemberAst)
            {
                if (invokeMemberAst.Member is StringConstantExpressionAst memberName &&
                    (memberName.Value.Equals("ContainsKey", StringComparison.OrdinalIgnoreCase) ||
                     memberName.Value.Equals("Remove", StringComparison.OrdinalIgnoreCase)))
                {
                    targetAst = invokeMemberAst.Expression;
                }
            }
            // Check for indexer: $PSBoundParameters['...']
            else if (lastAst.Parent is IndexExpressionAst indexAst)
            {
                targetAst = indexAst.Target;
            }

            if (targetAst is null)
            {
                return null;
            }

            // Check if target is $PSBoundParameters
            if (targetAst is not VariableExpressionAst variableAst ||
                !variableAst.VariablePath.UserPath.Equals("PSBoundParameters", StringComparison.OrdinalIgnoreCase))
            {
                return null;
            }

            // Find the nearest param block
            var paramBlockAst = FindNearestParamBlock(lastAst.Parent);

            if (paramBlockAst == null || paramBlockAst.Parameters.Count == 0)
            {
                return null;
            }

            // Generate completion results from parameter names
            var wordToComplete = completionContext.WordToComplete ?? string.Empty;

            // Determine quote style based on the string constant type
            string quoteChar = string.Empty;
            if (stringAst.StringConstantType == StringConstantType.SingleQuoted)
            {
                quoteChar = "'";
            }
            else if (stringAst.StringConstantType == StringConstantType.DoubleQuoted)
            {
                quoteChar = "\"";
            }

            return CreateParameterCompletionResults(paramBlockAst, wordToComplete, quoteChar);
        }

        /// <summary>
        /// Finds the nearest ParamBlockAst by traversing up the AST hierarchy.
        /// </summary>
        /// <param name="startAst">The AST node to start searching from.</param>
        /// <returns>The nearest ParamBlockAst if found; otherwise, null.</returns>
        private static ParamBlockAst FindNearestParamBlock(Ast startAst)
        {
            Ast current = startAst;
            while (current != null)
            {
                if (current is FunctionDefinitionAst functionDefinitionAst)
                {
                    return functionDefinitionAst.Body?.ParamBlock;
                }
                else if (current is ScriptBlockAst scriptBlockAst)
                {
                    var paramBlock = scriptBlockAst.ParamBlock;
                    if (paramBlock != null)
                    {
                        return paramBlock;
                    }
                }

                current = current.Parent;
            }

            return null;
        }

        /// <summary>
        /// Creates completion results from parameter names with optional quote wrapping.
        /// </summary>
        /// <param name="paramBlockAst">The parameter block containing parameters to complete.</param>
        /// <param name="wordToComplete">The partial word to match against parameter names.</param>
        /// <param name="quoteChar">Optional quote character to wrap completion text (empty string for no quotes).</param>
        /// <returns>A list of completion results, or null if no matches found.</returns>
        private static List<CompletionResult> CreateParameterCompletionResults(
            ParamBlockAst paramBlockAst,
            string wordToComplete,
            string quoteChar = "")
        {
            var result = paramBlockAst.Parameters
                .Select(parameter => parameter.Name.VariablePath.UserPath)
                .Where(parameterName => parameterName.StartsWith(wordToComplete, StringComparison.OrdinalIgnoreCase))
                .Select(parameterName =>
                    new CompletionResult(
                        quoteChar + parameterName + quoteChar,
                        parameterName,
                        CompletionResultType.ParameterValue,
                        parameterName))
                .ToList();

            return result.Count > 0 ? result : null;
        }

        private static bool CompleteOperator(Token tokenAtCursor, Ast lastAst)
        {
            if (tokenAtCursor.Kind == TokenKind.Minus)
            {
                return lastAst is BinaryExpressionAst;
            }
            else if (tokenAtCursor.Kind == TokenKind.Parameter)
            {
                if (lastAst is CommandParameterAst)
                    return lastAst.Parent is ExpressionAst;
            }

            return false;
        }

        private static bool CompleteAgainstStatementFlags(Ast scriptAst, Ast lastAst, Token token, out TokenKind kind)
        {
            kind = TokenKind.Unknown;

            // Handle "switch -f<tab>"
            var errorStatement = lastAst as ErrorStatementAst;
            if (errorStatement != null && errorStatement.Kind != null)
            {
                switch (errorStatement.Kind.Kind)
                {
                    case TokenKind.Switch:
                        kind = TokenKind.Switch;
                        return true;
                    default:
                        break;
                }
            }

            // Handle "switch -<tab>". Skip cases like "switch ($a) {} -<tab> "
            var scriptBlockAst = scriptAst as ScriptBlockAst;
            if (token != null && token.Kind == TokenKind.Minus && scriptBlockAst != null)
            {
                var asts = AstSearcher.FindAll(scriptBlockAst, ast => IsCursorAfterExtent(token.Extent.StartScriptPosition, ast.Extent), searchNestedScriptBlocks: true);

                Ast last = asts.LastOrDefault();
                errorStatement = null;

                while (last != null)
                {
                    errorStatement = last as ErrorStatementAst;
                    if (errorStatement != null) { break; }

                    last = last.Parent;
                }

                if (errorStatement != null && errorStatement.Kind != null)
                {
                    switch (errorStatement.Kind.Kind)
                    {
                        case TokenKind.Switch:

                            Tuple<Token, Ast> value;
                            if (errorStatement.Flags != null && errorStatement.Flags.TryGetValue(Parser.VERBATIM_ARGUMENT, out value))
                            {
                                if (IsTokenTheSame(value.Item1, token))
                                {
                                    kind = TokenKind.Switch;
                                    return true;
                                }
                            }

                            break;

                        default:
                            break;
                    }
                }
            }

            return false;
        }

        private static bool IsTokenTheSame(Token x, Token y)
        {
            if (x.Kind == y.Kind && x.TokenFlags == y.TokenFlags &&
                x.Extent.StartLineNumber == y.Extent.StartLineNumber &&
                x.Extent.StartColumnNumber == y.Extent.StartColumnNumber &&
                x.Extent.EndLineNumber == y.Extent.EndLineNumber &&
                x.Extent.EndColumnNumber == y.Extent.EndColumnNumber)
            {
                return true;
            }

            return false;
        }

        #endregion Special Cases

        internal List<CompletionResult> GetResults(PowerShell powerShell, out int replacementIndex, out int replacementLength)
        {
            var completionContext = CreateCompletionContext(powerShell);

            PSLanguageMode? previousLanguageMode = null;
            try
            {
                // Tab expansion is called from a trusted function - we should apply ConstrainedLanguage if necessary.
                if (completionContext.ExecutionContext.HasRunspaceEverUsedConstrainedLanguageMode)
                {
                    previousLanguageMode = completionContext.ExecutionContext.LanguageMode;
                    completionContext.ExecutionContext.LanguageMode = PSLanguageMode.ConstrainedLanguage;
                }

                return GetResultHelper(completionContext, out replacementIndex, out replacementLength);
            }
            finally
            {
                if (previousLanguageMode.HasValue)
                {
                    completionContext.ExecutionContext.LanguageMode = previousLanguageMode.Value;
                }
            }
        }

        internal List<CompletionResult> GetResultHelper(CompletionContext completionContext, out int replacementIndex, out int replacementLength)
        {
            replacementIndex = -1;
            replacementLength = -1;

            var tokenAtCursor = completionContext.TokenAtCursor;
            var lastAst = completionContext.RelatedAsts.Last();
            List<CompletionResult> result = null;
            if (tokenAtCursor != null)
            {
                replacementIndex = tokenAtCursor.Extent.StartScriptPosition.Offset;
                replacementLength = tokenAtCursor.Extent.EndScriptPosition.Offset - replacementIndex;

                completionContext.ReplacementIndex = replacementIndex;
                completionContext.ReplacementLength = replacementLength;

                switch (tokenAtCursor.Kind)
                {
                    case TokenKind.Variable:
                    case TokenKind.SplattedVariable:
                        completionContext.WordToComplete = ((VariableToken)tokenAtCursor).VariablePath.UserPath;
                        result = CompletionCompleters.CompleteVariable(completionContext);
                        break;

                    case TokenKind.Multiply:
                    case TokenKind.Generic:
                    case TokenKind.MinusMinus: // for native commands '--'
                    case TokenKind.Identifier:
                        if (!tokenAtCursor.TokenFlags.HasFlag(TokenFlags.TypeName))
                        {
                            result = CompleteUsingKeywords(completionContext.CursorPosition.Offset, _tokens, ref replacementIndex, ref replacementLength);
                            if (result is not null)
                            {
                                return result;
                            }

                            result = GetResultForIdentifier(completionContext, ref replacementIndex, ref replacementLength);
                        }

                        break;

                    case TokenKind.Parameter:
                        completionContext.WordToComplete = tokenAtCursor.Text;
                        var cmdAst = lastAst.Parent as CommandAst;
                        if (lastAst is StringConstantExpressionAst && cmdAst != null && cmdAst.CommandElements.Count == 1)
                        {
                            result = CompleteFileNameAsCommand(completionContext);
                            break;
                        }

                        TokenKind statementKind;
                        if (CompleteAgainstStatementFlags(null, lastAst, null, out statementKind))
                        {
                            result = CompletionCompleters.CompleteStatementFlags(statementKind, completionContext.WordToComplete);
                            break;
                        }

                        if (CompleteOperator(tokenAtCursor, lastAst))
                        {
                            result = CompletionCompleters.CompleteOperator(completionContext.WordToComplete);
                            break;
                        }

                        // Handle scenarios like this: dir -path:<tab>
                        if (completionContext.WordToComplete.EndsWith(':'))
                        {
                            replacementIndex = tokenAtCursor.Extent.EndScriptPosition.Offset;
                            replacementLength = 0;

                            completionContext.WordToComplete = string.Empty;
                            result = CompletionCompleters.CompleteCommandArgument(completionContext);
                        }
                        else
                        {
                            result = CompletionCompleters.CompleteCommandParameter(completionContext);
                        }

                        break;

                    case TokenKind.Dot:
                    case TokenKind.ColonColon:
                    case TokenKind.QuestionDot:
                        replacementIndex += tokenAtCursor.Text.Length;
                        replacementLength = 0;
                        result = CompletionCompleters.CompleteMember(completionContext, @static: tokenAtCursor.Kind == TokenKind.ColonColon, ref replacementLength);

                        break;

                    case TokenKind.Comment:
                        completionContext.WordToComplete = tokenAtCursor.Text;
                        result = CompletionCompleters.CompleteComment(completionContext, ref replacementIndex, ref replacementLength);
                        break;

                    case TokenKind.StringExpandable:
                    case TokenKind.StringLiteral:
                        // Search to see if we're looking at an assignment
                        if (lastAst.Parent is CommandExpressionAst
                            && lastAst.Parent.Parent is AssignmentStatementAst assignmentAst)
                        {
                            // Handle scenarios like `$ErrorActionPreference = '<tab>`
                            if (TryGetCompletionsForVariableAssignment(completionContext, assignmentAst, out List<CompletionResult> completions))
                            {
                                return completions;
                            }
                        }
                        else if (lastAst.Parent is BinaryExpressionAst binaryExpression)
                        {
                            completionContext.WordToComplete = (tokenAtCursor as StringToken).Value;
                            result = CompletionCompleters.CompleteComparisonOperatorValues(completionContext, binaryExpression.Left);
                            if (result.Count > 0)
                            {
                                return result;
                            }
                        }
                        else if (lastAst.Parent is IndexExpressionAst indexExpressionAst)
                        {
                            // Handles quoted string inside index expression like: $PSVersionTable["<Tab>"]
                            completionContext.WordToComplete = (tokenAtCursor as StringToken).Value;
                            // Check for $PSBoundParameters indexer first
                            var psBoundResult = CompleteAgainstPSBoundParametersAccess(completionContext);
                            if (psBoundResult != null && psBoundResult.Count > 0)
                            {
                                return psBoundResult;
                            }

                            return CompletionCompleters.CompleteIndexExpression(completionContext, indexExpressionAst.Target);
                        }

                        result = GetResultForString(completionContext, ref replacementIndex, ref replacementLength);
                        break;

                    case TokenKind.RBracket:
                        if (lastAst is TypeExpressionAst)
                        {
                            var targetExpr = (TypeExpressionAst)lastAst;
                            var memberResult = new List<CompletionResult>();

                            CompletionCompleters.CompleteMemberHelper(
                                true,
                                "*",
                                targetExpr,
                                completionContext, memberResult);

                            if (memberResult.Count > 0)
                            {
                                replacementIndex++;
                                replacementLength = 0;
                                result = (from entry in memberResult
                                          let completionText = TokenKind.ColonColon.Text() + entry.CompletionText
                                          select new CompletionResult(completionText, entry.ListItemText, entry.ResultType, entry.ToolTip)).ToList();
                            }
                        }

                        break;

                    case TokenKind.Comma:
                        // Handle array elements such as the followings:
                        //  - `dir .\cd,<tab>`
                        //  - `dir -Path: .\cd,<tab>`
                        //  - `dir .\abc.txt,<tab> -File`
                        //  - `dir -Path .\abc.txt,<tab> -File`
                        //  - `dir -Path: .\abc.txt,<tab> -File`
                        if (lastAst is ErrorExpressionAst or ArrayLiteralAst &&
                            lastAst.Parent is CommandAst or CommandParameterAst)
                        {
                            replacementIndex += replacementLength;
                            replacementLength = 0;

                            result = CompletionCompleters.CompleteCommandArgument(completionContext);
                        }
                        else if (lastAst is AttributeAst)
                        {
                            completionContext.ReplacementIndex = replacementIndex += tokenAtCursor.Text.Length;
                            completionContext.ReplacementLength = replacementLength = 0;
                            result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                        }
                        else
                        {
                            //
                            // Handle auto completion for enum/dependson property of DSC resource,
                            // cursor is right after ','
                            //
                            // Configuration config
                            // {
                            //     User test
                            //     {
                            //         DependsOn=@('[user]x',|)
                            //
                            result = GetResultForEnumPropertyValueOfDSCResource(completionContext, string.Empty, ref replacementIndex, ref replacementLength, out _);
                        }

                        break;
                    case TokenKind.AtCurly:
                        // Handle scenarios such as 'Sort-Object @{<tab>' and  'gci | Format-Table @{'
                        result = GetResultForHashtable(completionContext);
                        replacementIndex += 2;
                        replacementLength = 0;
                        break;

                    case TokenKind.Semi:
                        // Handle scenarios such as 'gci | Format-Table @{Label=...;<tab>'
                        if (lastAst is HashtableAst)
                        {
                            result = GetResultForHashtable(completionContext);
                            replacementIndex += 1;
                            replacementLength = 0;
                        }

                        break;

                    case TokenKind.Number:
                        // Handle scenarios such as Get-Process -Id 5<tab> || Get-Process -Id 5210, 3<tab> || Get-Process -Id: 5210, 3<tab>
                        if (lastAst is ConstantExpressionAst &&
                            (lastAst.Parent is CommandAst || lastAst.Parent is CommandParameterAst ||
                            (lastAst.Parent is ArrayLiteralAst &&
                             (lastAst.Parent.Parent is CommandAst || lastAst.Parent.Parent is CommandParameterAst))))
                        {
                            completionContext.WordToComplete = tokenAtCursor.Text;
                            result = CompletionCompleters.CompleteCommandArgument(completionContext);

                            replacementIndex = completionContext.ReplacementIndex;
                            replacementLength = completionContext.ReplacementLength;
                        }
                        else if (lastAst.Parent is CommandExpressionAst
                            && lastAst.Parent.Parent is AssignmentStatementAst assignmentAst2)
                        {
                            // Handle scenarios like '[ValidateSet(11,22)][int]$i = 11; $i = 2<tab>'
                            if (TryGetCompletionsForVariableAssignment(completionContext, assignmentAst2, out List<CompletionResult> completions))
                            {
                                result = completions;
                            }
                        }

                        break;

                    case TokenKind.Redirection:
                        // Handle file name completion after the redirection operator: gps ><tab> || gps >><tab> || dir con 2><tab> || dir con 2>><tab>
                        if (lastAst is ErrorExpressionAst && lastAst.Parent is FileRedirectionAst)
                        {
                            completionContext.WordToComplete = string.Empty;
                            completionContext.ReplacementIndex = (replacementIndex += tokenAtCursor.Text.Length);
                            completionContext.ReplacementLength = replacementLength = 0;
                            result = new List<CompletionResult>(CompletionCompleters.CompleteFilename(completionContext));
                        }

                        break;

                    case TokenKind.Minus:
                        // Handle operator completion: 55 -<tab> || "string" -<tab> || (Get-Something) -<tab>
                        if (CompleteOperator(tokenAtCursor, lastAst))
                        {
                            result = CompletionCompleters.CompleteOperator(string.Empty);
                            break;
                        }

                        // Handle the flag completion for statements, such as the switch statement
                        if (CompleteAgainstStatementFlags(completionContext.RelatedAsts[0], null, tokenAtCursor, out statementKind))
                        {
                            completionContext.WordToComplete = tokenAtCursor.Text;
                            result = CompletionCompleters.CompleteStatementFlags(statementKind, completionContext.WordToComplete);
                            break;
                        }

                        break;

                    case TokenKind.DynamicKeyword:
                        {
                            DynamicKeywordStatementAst keywordAst;
                            ConfigurationDefinitionAst configureAst = GetAncestorConfigurationAstAndKeywordAst(
                                completionContext.CursorPosition, lastAst, out keywordAst);
                            Diagnostics.Assert(configureAst != null, "ConfigurationDefinitionAst should never be null");
                            bool matched = false;
                            completionContext.WordToComplete = tokenAtCursor.Text.Trim();
                            // Current token is within ConfigurationDefinitionAst or DynamicKeywordStatementAst
                            return GetResultForIdentifierInConfiguration(completionContext, configureAst, null, out matched);
                        }
                    case TokenKind.Equals:
                    case TokenKind.AtParen:
                    case TokenKind.LParen:
                        {
                            if (lastAst is AttributeAst)
                            {
                                completionContext.ReplacementIndex = replacementIndex += tokenAtCursor.Text.Length;
                                completionContext.ReplacementLength = replacementLength = 0;
                                result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                            }
                            else if (lastAst is HashtableAst hashTableAst && lastAst.Parent is not DynamicKeywordStatementAst && CheckForPendingAssignment(hashTableAst))
                            {
                                // Handle scenarios such as 'gci | Format-Table @{Label=<tab>' if incomplete parsing of the assignment.
                                return null;
                            }
                            else if (lastAst is AssignmentStatementAst assignmentAst2)
                            {
                                completionContext.ReplacementIndex = replacementIndex += tokenAtCursor.Text.Length;
                                completionContext.ReplacementLength = replacementLength = 0;

                                // Handle scenarios like '$ErrorActionPreference =<tab>'
                                if (TryGetCompletionsForVariableAssignment(completionContext, assignmentAst2, out List<CompletionResult> completions))
                                {
                                    return completions;
                                }
                            }
                            else if (lastAst is VariableExpressionAst && lastAst.Parent is ParameterAst paramAst && paramAst.Attributes.Count > 0)
                            {
                                foreach (AttributeBaseAst attribute in paramAst.Attributes)
                                {
                                    if (IsCursorWithinOrJustAfterExtent(_cursorPosition, attribute.Extent))
                                    {
                                        completionContext.ReplacementIndex = replacementIndex += tokenAtCursor.Text.Length;
                                        completionContext.ReplacementLength = replacementLength = 0;
                                        result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                                        break;
                                    }
                                }
                            }
                            else
                            {
                                // Handle scenarios such as 'configuration foo { File ab { Attributes ='
                                // (auto completion for enum/dependson property of DSC resource),
                                // cursor is right after '=', '(' or '@('
                                //
                                // Configuration config
                                // {
                                //     User test
                                //     {
                                //         DependsOn=|
                                //         DependsOn=@(|)
                                //         DependsOn=(|
                                //
                                result = GetResultForEnumPropertyValueOfDSCResource(completionContext, string.Empty, ref replacementIndex, ref replacementLength, out _);
                            }

                            break;
                        }

                    case TokenKind.Format:
                    case TokenKind.Not:
                    case TokenKind.Bnot:
                    case TokenKind.And:
                    case TokenKind.Or:
                    case TokenKind.Xor:
                    case TokenKind.Band:
                    case TokenKind.Bor:
                    case TokenKind.Bxor:
                    case TokenKind.Join:
                    case TokenKind.Ieq:
                    case TokenKind.Ine:
                    case TokenKind.Ige:
                    case TokenKind.Igt:
                    case TokenKind.Ilt:
                    case TokenKind.Ile:
                    case TokenKind.Ilike:
                    case TokenKind.Inotlike:
                    case TokenKind.Imatch:
                    case TokenKind.Inotmatch:
                    case TokenKind.Ireplace:
                    case TokenKind.Icontains:
                    case TokenKind.Inotcontains:
                    case TokenKind.Iin:
                    case TokenKind.Inotin:
                    case TokenKind.Isplit:
                    case TokenKind.Ceq:
                    case TokenKind.Cne:
                    case TokenKind.Cge:
                    case TokenKind.Cgt:
                    case TokenKind.Clt:
                    case TokenKind.Cle:
                    case TokenKind.Clike:
                    case TokenKind.Cnotlike:
                    case TokenKind.Cmatch:
                    case TokenKind.Cnotmatch:
                    case TokenKind.Creplace:
                    case TokenKind.Ccontains:
                    case TokenKind.Cnotcontains:
                    case TokenKind.Cin:
                    case TokenKind.Cnotin:
                    case TokenKind.Csplit:
                    case TokenKind.Is:
                    case TokenKind.IsNot:
                    case TokenKind.As:
                    case TokenKind.Shl:
                    case TokenKind.Shr:
                        result = CompletionCompleters.CompleteOperator(tokenAtCursor.Text);
                        break;

                    case TokenKind.LBracket:
                        if (lastAst.Parent is IndexExpressionAst indexExpression)
                        {
                            // Handles index expression with cursor right after lbracket like: $PSVersionTable[<Tab>]
                            completionContext.WordToComplete = string.Empty;
                            result = CompletionCompleters.CompleteIndexExpression(completionContext, indexExpression.Target);
                            if (result.Count > 0)
                            {
                                replacementIndex++;
                                replacementLength--;
                            }
                        }
                        break;
                    default:
                        result = CompleteUsingKeywords(completionContext.CursorPosition.Offset, _tokens, ref replacementIndex, ref replacementLength);
                        if (result is not null)
                        {
                            return result;
                        }

                        if ((tokenAtCursor.TokenFlags & TokenFlags.Keyword) != 0)
                        {
                            completionContext.WordToComplete = tokenAtCursor.Text;

                            // Handle the file name completion
                            result = CompleteFileNameAsCommand(completionContext);

                            // Handle the command name completion
                            var commandNameResult = CompletionCompleters.CompleteCommand(completionContext);
                            if (commandNameResult != null && commandNameResult.Count > 0)
                            {
                                result.AddRange(commandNameResult);
                            }
                        }
                        else
                        {
                            replacementIndex = -1;
                            replacementLength = -1;
                        }

                        break;
                }
            }
            else
            {
                IScriptPosition cursor = completionContext.CursorPosition;
                bool isCursorLineEmpty = string.IsNullOrWhiteSpace(cursor.Line);
                var tokenBeforeCursor = completionContext.TokenBeforeCursor;
                bool isLineContinuationBeforeCursor = false;
                if (tokenBeforeCursor != null)
                {
                    //
                    // Handle following scenario, cursor is in next line and after a command call,
                    // we need to skip the command call autocompletion if there is no backtick character
                    // in the end of the previous line, since backtick means command call continues to the next line
                    //
                    // Configuration config
                    // {
                    //     User test
                    //     {
                    //         DependsOn=zzz
                    //         |
                    //
                    isLineContinuationBeforeCursor = completionContext.TokenBeforeCursor.Kind == TokenKind.LineContinuation;
                }

                bool skipAutoCompleteForCommandCall = isCursorLineEmpty && !isLineContinuationBeforeCursor;
                bool lastAstIsExpressionAst = lastAst is ExpressionAst;
                if (!skipAutoCompleteForCommandCall &&
                    (lastAst is CommandParameterAst || lastAst is CommandAst ||
                    (lastAstIsExpressionAst && lastAst.Parent is CommandAst) ||
                    (lastAstIsExpressionAst && lastAst.Parent is CommandParameterAst) ||
                    (lastAstIsExpressionAst && lastAst.Parent is ArrayLiteralAst &&
                    (lastAst.Parent.Parent is CommandAst || lastAst.Parent.Parent is CommandParameterAst))))
                {
                    completionContext.WordToComplete = string.Empty;

                    var hashTableAst = lastAst as HashtableAst;

                    // Do not do any tab completion if we have a hash table
                    // and an assignment is pending.  For cases like:
                    //   new-object System.Drawing.Point -prop @{ X=  -> Tab should not complete
                    // Note: This check works when all statements preceding the last are complete,
                    //       but if a preceding statement is incomplete this test fails because
                    //       the Ast mixes the statements due to incomplete parsing.
                    //   e.g.,
                    //   new-object System.Drawing.Point -prop @{ X = 100; Y =      <- Incomplete line
                    //   new-object new-object System.Drawing.Point -prop @{ X =    <- Tab will yield hash properties.
                    if (hashTableAst != null &&
                        CheckForPendingAssignment(hashTableAst))
                    {
                        return result;
                    }

                    if (hashTableAst != null)
                    {
                        completionContext.ReplacementIndex = replacementIndex = completionContext.CursorPosition.Offset;
                        completionContext.ReplacementLength = replacementLength = 0;
                        result = CompletionCompleters.CompleteHashtableKey(completionContext, hashTableAst);
                    }
                    else
                    {
                        result = CompletionCompleters.CompleteCommandArgument(completionContext);
                        replacementIndex = completionContext.ReplacementIndex;
                        replacementLength = completionContext.ReplacementLength;
                    }
                }
                else
                {
                    //
                    // Handle completion of empty line within configuration statement
                    // Ignore the auto completion if there is a backtick character in previous line
                    //
                    bool cursorAtLineContinuation;
                    if ((tokenAtCursor != null && tokenAtCursor.Kind == TokenKind.LineContinuation) ||
                        (tokenBeforeCursor != null && tokenBeforeCursor.Kind == TokenKind.LineContinuation))
                        cursorAtLineContinuation = true;
                    else
                        cursorAtLineContinuation = false;
                    if (isCursorLineEmpty && !cursorAtLineContinuation)
                    {
                        //
                        // Handle following scenario, both Configuration and DSC resource 'User' are not complete
                        // Check Hashtable first, and then fallback to configuration
                        //
                        // Configuration config
                        // {
                        //     User test
                        //     {
                        //         DependsOn=''
                        //         |
                        result = GetResultForHashtable(completionContext);
                        if (result == null || result.Count == 0)
                        {
                            DynamicKeywordStatementAst keywordAst;
                            ConfigurationDefinitionAst configAst = GetAncestorConfigurationAstAndKeywordAst(cursor, lastAst, out keywordAst);
                            if (configAst != null)
                            {
                                bool matched;
                                result = GetResultForIdentifierInConfiguration(completionContext, configAst, keywordAst, out matched);
                            }
                        }

                        // Handles following scenario where user is tab completing a member on an empty line:
                        // "Hello".
                        // <Tab>
                        if ((result is null || result.Count == 0) && tokenBeforeCursor is not null)
                        {
                            switch (completionContext.TokenBeforeCursor.Kind)
                            {

                                case TokenKind.Dot:
                                case TokenKind.ColonColon:
                                case TokenKind.QuestionDot:
                                    replacementIndex = cursor.Offset;
                                    replacementLength = 0;
                                    result = CompletionCompleters.CompleteMember(completionContext, @static: completionContext.TokenBeforeCursor.Kind == TokenKind.ColonColon, ref replacementLength);
                                    break;

                                case TokenKind.LParen:
                                case TokenKind.Comma:
                                    if (lastAst is AttributeAst)
                                    {
                                        result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                                    }

                                    if (lastAst is VariableExpressionAst && lastAst.Parent is ParameterAst paramAst && paramAst.Attributes.Count > 0)
                                    {
                                        foreach (AttributeBaseAst attribute in paramAst.Attributes)
                                        {
                                            if (IsCursorWithinOrJustAfterExtent(_cursorPosition, attribute.Extent))
                                            {
                                                result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                                                break;
                                            }
                                        }
                                    }
                                    break;

                                case TokenKind.Ieq:
                                case TokenKind.Ceq:
                                case TokenKind.Ine:
                                case TokenKind.Cne:
                                case TokenKind.Ilike:
                                case TokenKind.Clike:
                                case TokenKind.Inotlike:
                                case TokenKind.Cnotlike:
                                case TokenKind.Imatch:
                                case TokenKind.Cmatch:
                                case TokenKind.Inotmatch:
                                case TokenKind.Cnotmatch:
                                    if (lastAst is BinaryExpressionAst binaryExpression)
                                    {
                                        completionContext.WordToComplete = string.Empty;
                                        result = CompletionCompleters.CompleteComparisonOperatorValues(completionContext, binaryExpression.Left);
                                    }
                                    break;

                                case TokenKind.LBracket:
                                    if (lastAst.Parent is IndexExpressionAst indexExpression)
                                    {
                                        // Handles index expression where cursor is on a new line after the lbracket like: $PSVersionTable[\n<Tab>]
                                        completionContext.WordToComplete = string.Empty;
                                        result = CompletionCompleters.CompleteIndexExpression(completionContext, indexExpression.Target);
                                    }
                                    break;

                                default:
                                    break;
                            }
                        }
                    }
                    else if (completionContext.TokenAtCursor == null)
                    {
                        if (tokenBeforeCursor != null)
                        {
                            //
                            // Handle auto completion for enum/dependson property of DSC resource,
                            // cursor is after '=', ',', '(', or '@('
                            //
                            // Configuration config
                            // {
                            //     User test
                            //     {
                            //         DependsOn= |
                            //         DependsOn=@('[user]x', |)
                            //         DependsOn=@( |)
                            //         DependsOn=(|
                            //
                            switch (tokenBeforeCursor.Kind)
                            {
                                case TokenKind.Equals:
                                case TokenKind.Comma:
                                case TokenKind.AtParen:
                                case TokenKind.LParen:
                                    {
                                        if (lastAst is AssignmentStatementAst assignmentAst)
                                        {
                                            // Handle scenarios like '$ErrorActionPreference = <tab>'
                                            if (TryGetCompletionsForVariableAssignment(completionContext, assignmentAst, out result))
                                            {
                                                break;
                                            }
                                        }

                                        if (lastAst is AttributeAst)
                                        {
                                            completionContext.ReplacementLength = replacementLength = 0;
                                            result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                                            break;
                                        }

                                        if (lastAst is VariableExpressionAst && lastAst.Parent is ParameterAst paramAst && paramAst.Attributes.Count > 0)
                                        {
                                            foreach (AttributeBaseAst attribute in paramAst.Attributes)
                                            {
                                                if (IsCursorWithinOrJustAfterExtent(_cursorPosition, attribute.Extent))
                                                {
                                                    completionContext.ReplacementLength = replacementLength = 0;
                                                    result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                                                    break;
                                                }
                                            }

                                            break;
                                        }

                                        result = GetResultForEnumPropertyValueOfDSCResource(completionContext, string.Empty, ref replacementIndex, ref replacementLength, out _);
                                        break;
                                    }

                                case TokenKind.Break:
                                case TokenKind.Continue:
                                    {
                                        if ((lastAst is BreakStatementAst breakStatement && breakStatement.Label is null)
                                            || (lastAst is ContinueStatementAst continueStatement && continueStatement.Label is null))
                                        {
                                            result = CompleteLoopLabel(completionContext);
                                        }
                                        break;
                                    }

                                case TokenKind.Using:
                                    return CompleteUsingKeywords(completionContext.CursorPosition.Offset, _tokens, ref replacementIndex, ref replacementLength);

                                case TokenKind.Dot:
                                case TokenKind.ColonColon:
                                case TokenKind.QuestionDot:
                                    // Handles following scenario with whitespace after member access token: "Hello". <Tab>
                                    replacementIndex = cursor.Offset;
                                    replacementLength = 0;
                                    result = CompletionCompleters.CompleteMember(completionContext, @static: tokenBeforeCursor.Kind == TokenKind.ColonColon, ref replacementLength);
                                    if (result is not null && result.Count > 0)
                                    {
                                        return result;
                                    }
                                    break;

                                case TokenKind.Ieq:
                                case TokenKind.Ceq:
                                case TokenKind.Ine:
                                case TokenKind.Cne:
                                case TokenKind.Ilike:
                                case TokenKind.Clike:
                                case TokenKind.Inotlike:
                                case TokenKind.Cnotlike:
                                case TokenKind.Imatch:
                                case TokenKind.Cmatch:
                                case TokenKind.Inotmatch:
                                case TokenKind.Cnotmatch:
                                    if (lastAst is BinaryExpressionAst binaryExpression)
                                    {
                                        completionContext.WordToComplete = string.Empty;
                                        result = CompletionCompleters.CompleteComparisonOperatorValues(completionContext, binaryExpression.Left);
                                    }
                                    break;

                                case TokenKind.LBracket:
                                    if (lastAst.Parent is IndexExpressionAst indexExpression)
                                    {
                                        // Handles index expression with whitespace between lbracket and cursor like: $PSVersionTable[ <Tab>]
                                        completionContext.WordToComplete = string.Empty;
                                        result = CompletionCompleters.CompleteIndexExpression(completionContext, indexExpression.Target);
                                    }
                                    break;

                                default:
                                    break;
                            }
                        }
                    }

                    if (result != null && result.Count > 0)
                    {
                        completionContext.ReplacementIndex = replacementIndex = completionContext.CursorPosition.Offset;
                        completionContext.ReplacementLength = replacementLength = 0;
                    }
                    else
                    {
                        bool needFileCompletion = false;
                        if (lastAst is ErrorExpressionAst && lastAst.Parent is FileRedirectionAst)
                        {
                            // Handle file name completion after redirection operator: gps > <tab>
                            needFileCompletion = true;
                        }
                        else if (lastAst is ErrorStatementAst && CompleteAgainstSwitchFile(lastAst, completionContext.TokenBeforeCursor))
                        {
                            // Handle file name completion after "switch -file": switch -file <tab>
                            needFileCompletion = true;
                        }

                        if (needFileCompletion)
                        {
                            completionContext.WordToComplete = string.Empty;
                            result = new List<CompletionResult>(CompletionCompleters.CompleteFilename(completionContext));

                            replacementIndex = completionContext.ReplacementIndex;
                            replacementLength = completionContext.ReplacementLength;
                        }
                    }
                }
            }

            if (result == null || result.Count == 0)
            {
                var typeAst = completionContext.RelatedAsts.OfType<TypeExpressionAst>().FirstOrDefault();
                TypeName typeNameToComplete = null;
                if (typeAst != null)
                {
                    typeNameToComplete = FindTypeNameToComplete(typeAst.TypeName, _cursorPosition);
                }
                else
                {
                    var typeConstraintAst = completionContext.RelatedAsts.OfType<TypeConstraintAst>().FirstOrDefault();
                    if (typeConstraintAst != null)
                    {
                        typeNameToComplete = FindTypeNameToComplete(typeConstraintAst.TypeName, _cursorPosition);
                    }
                }

                if (typeNameToComplete is null && tokenAtCursor?.TokenFlags.HasFlag(TokenFlags.TypeName) == true)
                {
                    typeNameToComplete = new TypeName(tokenAtCursor.Extent, tokenAtCursor.Text);
                }

                if (typeNameToComplete != null)
                {
                    // See if the typename to complete really is within the typename, and if so, which one, in the case of generics.

                    replacementIndex = typeNameToComplete.Extent.StartOffset;
                    replacementLength = typeNameToComplete.Extent.EndOffset - replacementIndex;
                    completionContext.WordToComplete = typeNameToComplete.FullName;
                    return CompletionCompleters.CompleteType(completionContext);
                }
            }

            if (result == null || result.Count == 0)
            {
                result = GetResultForHashtable(completionContext);
                // Handles the following scenario: [ipaddress]@{Address=""; <Tab> }
                if (result?.Count > 0)
                {
                    replacementIndex = completionContext.CursorPosition.Offset;
                    replacementLength = 0;
                }
            }

            if (result == null || result.Count == 0)
            {
                // Handle special file completion scenarios: .\+file.txt -> +<tab>
                string input = completionContext.RelatedAsts[0].Extent.Text;
                if (Regex.IsMatch(input, @"^[\S]+$") && completionContext.RelatedAsts.Count > 0 && completionContext.RelatedAsts[0] is ScriptBlockAst)
                {
                    replacementIndex = completionContext.RelatedAsts[0].Extent.StartScriptPosition.Offset;
                    replacementLength = completionContext.RelatedAsts[0].Extent.EndScriptPosition.Offset - replacementIndex;

                    completionContext.WordToComplete = input;
                    result = CompleteFileNameAsCommand(completionContext);
                }
            }

            return result;
        }

        // Helper method to auto complete hashtable key
        private static List<CompletionResult> GetResultForHashtable(CompletionContext completionContext)
        {
            Ast lastRelatedAst = null;
            var cursorPosition = completionContext.CursorPosition;

            // Enumeration is used over the LastAst pattern because empty lines following a key-value pair will set LastAst to the value.
            // Example:
            // @{
            //     Key1="Value1"
            //     <Tab>
            // }
            // In this case the last 3 Asts will be StringConstantExpression, CommandExpression, and Pipeline instead of the expected Hashtable
            for (int i = completionContext.RelatedAsts.Count - 1; i >= 0; i--)
            {
                Ast ast = completionContext.RelatedAsts[i];
                if (cursorPosition.Offset >= ast.Extent.StartOffset && cursorPosition.Offset <= ast.Extent.EndOffset)
                {
                    lastRelatedAst = ast;
                    break;
                }
            }

            if (lastRelatedAst is HashtableAst hashtableAst)
            {
                // Cursor is just after the hashtable: @{}<Tab>
                if (completionContext.TokenAtCursor is not null && completionContext.TokenAtCursor.Kind == TokenKind.RCurly)
                {
                    return null;
                }

                bool cursorIsWithinOrOnSameLineAsKeypair = false;
                foreach (var pair in hashtableAst.KeyValuePairs)
                {
                    if (cursorPosition.Offset >= pair.Item1.Extent.StartOffset
                        && (cursorPosition.Offset <= pair.Item2.Extent.EndOffset || cursorPosition.LineNumber == pair.Item2.Extent.EndLineNumber))
                    {
                        cursorIsWithinOrOnSameLineAsKeypair = true;
                        break;
                    }
                }

                if (cursorIsWithinOrOnSameLineAsKeypair)
                {
                    var tokenBeforeOrAtCursor = completionContext.TokenBeforeCursor ?? completionContext.TokenAtCursor;
                    if (tokenBeforeOrAtCursor.Kind != TokenKind.Semi)
                    {
                        return null;
                    }
                }
                completionContext.ReplacementIndex = completionContext.CursorPosition.Offset;
                completionContext.ReplacementLength = 0;
                return CompletionCompleters.CompleteHashtableKey(completionContext, hashtableAst);
            }

            return null;
        }

        // Helper method to look for an incomplete assignment pair in hash table.
        private static bool CheckForPendingAssignment(HashtableAst hashTableAst)
        {
            foreach (var keyValue in hashTableAst.KeyValuePairs)
            {
                if (keyValue.Item2 is ErrorStatementAst)
                {
                    // This indicates the assignment has not completed.
                    return true;
                }
            }

            return false;
        }

        internal static TypeName FindTypeNameToComplete(ITypeName type, IScriptPosition cursor)
        {
            var typeName = type as TypeName;
            if (typeName != null)
            {
                // If the cursor is at the start offset, it's not really inside, so return null.
                // If the cursor is at the end offset, it's not really inside, but it's just before the cursor,
                // we don want to complete it.
                return (cursor.Offset > type.Extent.StartOffset && cursor.Offset <= type.Extent.EndOffset)
                           ? typeName
                           : null;
            }

            var genericTypeName = type as GenericTypeName;
            if (genericTypeName != null)
            {
                typeName = FindTypeNameToComplete(genericTypeName.TypeName, cursor);
                if (typeName != null)
                    return typeName;
                foreach (var t in genericTypeName.GenericArguments)
                {
                    typeName = FindTypeNameToComplete(t, cursor);
                    if (typeName != null)
                        return typeName;
                }

                return null;
            }

            var arrayTypeName = type as ArrayTypeName;
            if (arrayTypeName != null)
            {
                return FindTypeNameToComplete(arrayTypeName.ElementType, cursor) ?? null;
            }

            return null;
        }

        private static string GetFirstLineSubString(string stringToComplete, out bool hasNewLine)
        {
            hasNewLine = false;
            if (!string.IsNullOrEmpty(stringToComplete))
            {
                var index = stringToComplete.AsSpan().IndexOfAny('\r', '\n');
                if (index >= 0)
                {
                    stringToComplete = stringToComplete.Substring(0, index);
                    hasNewLine = true;
                }
            }

            return stringToComplete;
        }

        private static Tuple<ExpressionAst, StatementAst> GetHashEntryContainsCursor(
            IScriptPosition cursor,
            HashtableAst hashTableAst,
            bool isCursorInString)
        {
            Tuple<ExpressionAst, StatementAst> keyValuePairWithCursor = null;
            foreach (var kvp in hashTableAst.KeyValuePairs)
            {
                if (IsCursorWithinOrJustAfterExtent(cursor, kvp.Item2.Extent))
                {
                    keyValuePairWithCursor = kvp;
                    break;
                }

                if (!isCursorInString)
                {
                    //
                    // Handle following case, cursor is after '=' but before next key value pair,
                    // next key value pair will be treated as kvp.Item2 of 'Ensure' key
                    //
                    //    configuration foo
                    //    {
                    //        File foo
                    //        {
                    //            DestinationPath = "\foo.txt"
                    //            Ensure = |
                    //            DependsOn =@("[User]x")
                    //        }
                    //    }
                    //
                    if (kvp.Item2.Extent.StartLineNumber > kvp.Item1.Extent.EndLineNumber &&
                        IsCursorAfterExtentAndInTheSameLine(cursor, kvp.Item1.Extent))
                    {
                        keyValuePairWithCursor = kvp;
                        break;
                    }

                    //
                    // If cursor is not within a string, then handle following two cases,
                    //
                    //  #1) cursor is after '=', in the same line of previous key value pair
                    //      configuration test{File testfile{DestinationPath='c:\test'; Ensure = |
                    //
                    //  #2) cursor is after '=', in the separate line of previous key value pair
                    //      configuration test{File testfile{DestinationPath='c:\test';
                    //        Ensure = |
                    //
                    if (!IsCursorBeforeExtent(cursor, kvp.Item1.Extent) &&
                        IsCursorAfterExtentAndInTheSameLine(cursor, kvp.Item2.Extent))
                    {
                        keyValuePairWithCursor = kvp;
                    }
                }
            }

            return keyValuePairWithCursor;
        }

        // Pulls the variable out of an assignment's LHS expression
        // Also brings back the innermost type constraint if there is one
        private static VariableExpressionAst GetVariableFromExpressionAst(
            ExpressionAst expression,
            ref Type typeConstraint,
            ref ValidateSetAttribute setConstraint)
        {
            switch (expression)
            {
                // $x = ...
                case VariableExpressionAst variableExpression:
                    return variableExpression;

                // [type]$x = ...
                case ConvertExpressionAst convertExpression:
                    typeConstraint = convertExpression.Type.TypeName.GetReflectionType();
                    return GetVariableFromExpressionAst(convertExpression.Child, ref typeConstraint, ref setConstraint);

                // [attribute()][type]$x = ...
                case AttributedExpressionAst attributedExpressionAst:

                    try
                    {
                        setConstraint = attributedExpressionAst.Attribute.GetAttribute() as ValidateSetAttribute;
                    }
                    catch
                    {
                        // Do nothing, just prevent fallout from an unsuccessful attribute conversion
                    }

                    return GetVariableFromExpressionAst(attributedExpressionAst.Child, ref typeConstraint, ref setConstraint);

                // Something else, like `MemberExpressionAst` $a.p = <tab> which isn't currently handled
                default:
                    return null;
            }
        }

        // Gets any type constraints or validateset constraints on a given variable
        private static bool TryGetTypeConstraintOnVariable(
            CompletionContext completionContext,
            string variableName,
            out Type typeConstraint,
            out ValidateSetAttribute setConstraint)
        {
            typeConstraint = null;
            setConstraint = null;

            PSVariable variable = completionContext.ExecutionContext.EngineSessionState.GetVariable(variableName);

            if (variable == null || variable.Attributes.Count == 0)
            {
                return false;
            }

            foreach (Attribute attribute in variable.Attributes)
            {
                if (attribute is ArgumentTypeConverterAttribute typeConverterAttribute)
                {
                    typeConstraint = typeConverterAttribute.TargetType;
                    continue;
                }

                if (attribute is ValidateSetAttribute validateSetAttribute)
                {
                    setConstraint = validateSetAttribute;
                }
            }

            return typeConstraint != null || setConstraint != null;
        }

        private static List<CompletionResult> CompletePropertyAssignment(MemberExpressionAst memberExpression, CompletionContext context)
        {
            if (SafeExprEvaluator.TrySafeEval(memberExpression, context.ExecutionContext, out var evalValue))
            {
                if (evalValue is not null)
                {
                    Type type = evalValue.GetType();
                    if (type.IsEnum)
                    {
                        return GetResultForEnum(type, context);
                    }

                    return null;
                }
            }

            _ = TryGetInferredCompletionsForAssignment(memberExpression, context, out List<CompletionResult> result);
            return result;
        }

        private static bool TryGetInferredCompletionsForAssignment(Ast expression, CompletionContext context, out List<CompletionResult> result)
        {
            result = null;
            IList<PSTypeName> inferredTypes;
            if (expression.Parent is ConvertExpressionAst convertExpression)
            {
                inferredTypes = new PSTypeName[] { new(convertExpression.Type.TypeName) };
            }
            else if (expression is MemberExpressionAst)
            {
                inferredTypes = AstTypeInference.InferTypeOf(expression);
            }
            else if (expression is VariableExpressionAst varExpression)
            {
                PSTypeName typeConstraint = CompletionCompleters.GetLastDeclaredTypeConstraint(varExpression, context.TypeInferenceContext);
                if (typeConstraint is null)
                {
                    return false;
                }

                inferredTypes = new PSTypeName[] { typeConstraint };
            }
            else
            {
                return false;
            }

            if (inferredTypes.Count == 0)
            {
                return false;
            }

            var values = new SortedSet<string>();
            foreach (PSTypeName type in inferredTypes)
            {
                Type loadedType = type.Type;
                if (loadedType is not null)
                {
                    if (loadedType.IsEnum)
                    {
                        foreach (string value in Enum.GetNames(loadedType))
                        {
                            _ = values.Add(value);
                        }
                    }
                }
                else if (type is not null && type.TypeDefinitionAst.IsEnum)
                {
                    foreach (MemberAst member in type.TypeDefinitionAst.Members)
                    {
                        if (member is PropertyMemberAst property)
                        {
                            _ = values.Add(property.Name);
                        }
                    }
                }
            }

            string wordToComplete;
            if (string.IsNullOrEmpty(context.WordToComplete))
            {
                if (context.TokenAtCursor is not null && context.TokenAtCursor.Kind != TokenKind.Equals)
                {
                    wordToComplete = context.TokenAtCursor.Text + "*";
                }
                else
                {
                    wordToComplete = "*";
                }
            }
            else
            {
                wordToComplete = context.WordToComplete + "*";
            }

            result = new List<CompletionResult>();
            var pattern = new WildcardPattern(wordToComplete, WildcardOptions.IgnoreCase);
            foreach (string name in values)
            {
                string quotedName = GetQuotedString(name, context);
                if (pattern.IsMatch(quotedName))
                {
                    result.Add(new CompletionResult(quotedName, name, CompletionResultType.Property, name));
                }
            }

            if (result.Count == 0)
            {
                result = null;
                return false;
            }

            return true;
        }

        private static bool TryGetCompletionsForVariableAssignment(
            CompletionContext completionContext,
            AssignmentStatementAst assignmentAst,
            out List<CompletionResult> completions)
        {
            bool TryGetResultForEnum(Type typeConstraint, CompletionContext completionContext, out List<CompletionResult> completions)
            {
                completions = null;

                if (typeConstraint != null && typeConstraint.IsEnum)
                {
                    completions = GetResultForEnum(typeConstraint, completionContext);
                    return true;
                }

                return false;
            }

            bool TryGetResultForSet(Type typeConstraint, ValidateSetAttribute setConstraint, CompletionContext completionContext1, out List<CompletionResult> completions)
            {
                completions = null;

                if (setConstraint?.ValidValues != null)
                {
                    completions = GetResultForSet(typeConstraint, setConstraint.ValidValues, completionContext);
                    return true;
                }

                return false;
            }

            if (assignmentAst.Left is MemberExpressionAst member)
            {
                completions = CompletePropertyAssignment(member, completionContext);
                return completions is not null;
            }

            completions = null;

            // Try to get the variable from the assignment, plus any type constraint on it
            Type typeConstraint = null;
            ValidateSetAttribute setConstraint = null;
            VariableExpressionAst variableAst = GetVariableFromExpressionAst(assignmentAst.Left, ref typeConstraint, ref setConstraint);

            if (variableAst == null)
            {
                return false;
            }

            // Assignment constraints override any existing ones, so try them first

            // Check any [ValidateSet()] constraint first since it's likely to be narrow
            if (TryGetResultForSet(typeConstraint, setConstraint, completionContext, out completions))
            {
                return true;
            }

            // Then try to complete for an enum type
            if (TryGetResultForEnum(typeConstraint, completionContext, out completions))
            {
                return true;
            }

            // If the assignment itself was unconstrained, the variable still might be
            if (!TryGetTypeConstraintOnVariable(completionContext, variableAst.VariablePath.UserPath, out typeConstraint, out setConstraint))
            {
                return TryGetInferredCompletionsForAssignment(variableAst, completionContext, out completions);
            }

            // Again try the [ValidateSet()] constraint first
            if (TryGetResultForSet(typeConstraint, setConstraint, completionContext, out completions))
            {
                return true;
            }

            // Then try to complete for an enum type again
            if (TryGetResultForEnum(typeConstraint, completionContext, out completions))
            {
                return true;
            }

            return false;
        }

        private static List<CompletionResult> GetResultForSet(
            Type typeConstraint,
            IList<string> validValues,
            CompletionContext completionContext)
        {
            var allValues = new List<string>();
            foreach (string value in validValues)
            {
                if (typeConstraint != null && (typeConstraint == typeof(string) || typeConstraint.IsEnum))
                {
                    allValues.Add(GetQuotedString(value, completionContext));
                }
                else
                {
                    allValues.Add(value);
                }
            }

            return GetMatchedResults(allValues, completionContext);
        }

        private static List<CompletionResult> GetMatchedResults(
            List<string> allValues,
            CompletionContext completionContext)
        {
            var stringToComplete = string.Empty;
            if (completionContext.TokenAtCursor != null && completionContext.TokenAtCursor.Kind != TokenKind.Equals)
            {
                stringToComplete = completionContext.TokenAtCursor.Text;
            }

            IEnumerable<string> matchedResults = null;

            if (!string.IsNullOrEmpty(stringToComplete))
            {
                string matchString = stringToComplete + "*";
                var wildcardPattern = WildcardPattern.Get(matchString, WildcardOptions.IgnoreCase | WildcardOptions.CultureInvariant);

                matchedResults = allValues.Where(r => wildcardPattern.IsMatch(r));
            }
            else
            {
                matchedResults = allValues;
            }

            var result = new List<CompletionResult>();
            foreach (var match in matchedResults)
            {
                result.Add(new CompletionResult(match));
            }

            return result;
        }

        private static string GetQuotedString(
            string value,
            CompletionContext completionContext)
        {
            var stringToComplete = string.Empty;
            if (completionContext.TokenAtCursor != null)
            {
                stringToComplete = completionContext.TokenAtCursor.Text;
            }

            var quote = stringToComplete.StartsWith('"') ? "\"" : "'";
            return quote + value + quote;
        }

        private static List<CompletionResult> GetResultForEnum(
            Type type,
            CompletionContext completionContext)
        {
            var allNames = new List<string>();
            foreach (var name in Enum.GetNames(type))
            {
                allNames.Add(GetQuotedString(name, completionContext));
            }

            allNames.Sort();

            return GetMatchedResults(allNames, completionContext);
        }

        private static List<CompletionResult> GetResultForEnumPropertyValueOfDSCResource(
            CompletionContext completionContext,
            string stringToComplete,
            ref int replacementIndex,
            ref int replacementLength,
            out bool shouldContinue)
        {
            shouldContinue = true;
            bool isCursorInString = completionContext.TokenAtCursor is StringToken;
            List<CompletionResult> result = null;
            var lastAst = completionContext.RelatedAsts.Last();
            Ast lastChildofHashtableAst;
            var hashTableAst = Ast.GetAncestorHashtableAst(lastAst, out lastChildofHashtableAst);
            Diagnostics.Assert(stringToComplete != null, "stringToComplete should never be null");
            // Check if the hashtable within a DynamicKeyword statement
            if (hashTableAst != null)
            {
                var keywordAst = Ast.GetAncestorAst<DynamicKeywordStatementAst>(hashTableAst);
                if (keywordAst != null)
                {
                    IScriptPosition cursor = completionContext.CursorPosition;
                    var keyValuePairWithCursor = GetHashEntryContainsCursor(cursor, hashTableAst, isCursorInString);
                    if (keyValuePairWithCursor != null)
                    {
                        var propertyNameAst = keyValuePairWithCursor.Item1 as StringConstantExpressionAst;
                        if (propertyNameAst != null)
                        {
                            DynamicKeywordProperty property;
                            if (keywordAst.Keyword.Properties.TryGetValue(propertyNameAst.Value, out property))
                            {
                                List<string> existingValues = null;
                                WildcardPattern wildcardPattern = null;
                                bool isDependsOnProperty = string.Equals(property.Name, @"DependsOn", StringComparison.OrdinalIgnoreCase);
                                bool hasNewLine = false;
                                string stringQuote = (completionContext.TokenAtCursor is StringExpandableToken) ? "\"" : "'";
                                if ((property.ValueMap != null && property.ValueMap.Count > 0) || isDependsOnProperty)
                                {
                                    shouldContinue = false;
                                    existingValues = new List<string>();
                                    if (string.Equals(property.TypeConstraint, "StringArray", StringComparison.OrdinalIgnoreCase))
                                    {
                                        var arrayAst = Ast.GetAncestorAst<ArrayLiteralAst>(lastAst);
                                        if (arrayAst != null && arrayAst.Elements.Count > 0)
                                        {
                                            foreach (ExpressionAst expression in arrayAst.Elements)
                                            {
                                                //
                                                // stringAst can be null in following case
                                                //      DependsOn='[user]x',|
                                                //
                                                var stringAst = expression as StringConstantExpressionAst;
                                                if (stringAst != null && IsCursorOutsideOfExtent(cursor, expression.Extent))
                                                {
                                                    existingValues.Add(stringAst.Value);
                                                }
                                            }
                                        }
                                    }
                                    //
                                    // Make sure only auto-complete string value in current line
                                    //
                                    stringToComplete = GetFirstLineSubString(stringToComplete, out hasNewLine);
                                    completionContext.WordToComplete = stringToComplete;
                                    replacementLength = completionContext.ReplacementLength = stringToComplete.Length;
                                    //
                                    // Calculate the replacementIndex based on cursor location (relative to the string token)
                                    //
                                    if (completionContext.TokenAtCursor is StringToken)
                                    {
                                        replacementIndex = completionContext.TokenAtCursor.Extent.StartOffset + 1;
                                    }
                                    else
                                    {
                                        replacementIndex = completionContext.CursorPosition.Offset - replacementLength;
                                    }

                                    completionContext.ReplacementIndex = replacementIndex;
                                    string matchString = stringToComplete + "*";
                                    wildcardPattern = WildcardPattern.Get(matchString, WildcardOptions.IgnoreCase | WildcardOptions.CultureInvariant);
                                    result = new List<CompletionResult>();
                                }

                                Diagnostics.Assert(isCursorInString || (!hasNewLine), "hasNoQuote and hasNewLine cannot be true at the same time");
                                if (property.ValueMap != null && property.ValueMap.Count > 0)
                                {
                                    IEnumerable<string> orderedValues = property.ValueMap.Keys.Order().Where(v => !existingValues.Contains(v, StringComparer.OrdinalIgnoreCase));
                                    var matchedResults = orderedValues.Where(v => wildcardPattern.IsMatch(v));
                                    if (matchedResults == null || !matchedResults.Any())
                                    {
                                        // Fallback to all allowed values
                                        matchedResults = orderedValues;
                                    }

                                    foreach (var value in matchedResults)
                                    {
                                        string completionText = isCursorInString ? value : stringQuote + value + stringQuote;
                                        if (hasNewLine)
                                            completionText += stringQuote;
                                        result.Add(new CompletionResult(
                                            completionText,
                                            value,
                                            CompletionResultType.Text,
                                            value));
                                    }
                                }
                                else if (isDependsOnProperty)
                                {
                                    var configAst = Ast.GetAncestorAst<ConfigurationDefinitionAst>(keywordAst);
                                    if (configAst != null)
                                    {
                                        var namedBlockAst = Ast.GetAncestorAst<NamedBlockAst>(keywordAst);
                                        if (namedBlockAst != null)
                                        {
                                            List<string> allResources = new List<string>();
                                            foreach (var statementAst in namedBlockAst.Statements)
                                            {
                                                var dynamicKeywordAst = statementAst as DynamicKeywordStatementAst;
                                                if (dynamicKeywordAst != null &&
                                                    dynamicKeywordAst != keywordAst &&
                                                    !string.Equals(dynamicKeywordAst.Keyword.Keyword, @"Node", StringComparison.OrdinalIgnoreCase))
                                                {
                                                    if (!string.IsNullOrEmpty(dynamicKeywordAst.ElementName))
                                                    {
                                                        StringBuilder sb = new StringBuilder("[", 50);
                                                        sb.Append(dynamicKeywordAst.Keyword.Keyword);
                                                        sb.Append(']');
                                                        sb.Append(dynamicKeywordAst.ElementName);
                                                        var resource = sb.ToString();
                                                        if (!existingValues.Contains(resource, StringComparer.OrdinalIgnoreCase) &&
                                                            !allResources.Contains(resource, StringComparer.OrdinalIgnoreCase))
                                                        {
                                                            allResources.Add(resource);
                                                        }
                                                    }
                                                }
                                            }

                                            var matchedResults = allResources.Where(r => wildcardPattern.IsMatch(r));
                                            if (matchedResults == null || !matchedResults.Any())
                                            {
                                                // Fallback to all allowed values
                                                matchedResults = allResources;
                                            }

                                            foreach (var resource in matchedResults)
                                            {
                                                string completionText = isCursorInString ? resource : stringQuote + resource + stringQuote;
                                                if (hasNewLine)
                                                    completionText += stringQuote;
                                                result.Add(new CompletionResult(
                                                    completionText,
                                                    resource,
                                                    CompletionResultType.Text,
                                                    resource));
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }

            return result;
        }

        private static List<CompletionResult> GetResultForString(CompletionContext completionContext, ref int replacementIndex, ref int replacementLength)
        {
            var lastAst = completionContext.RelatedAsts.Last();
            var expandableString = lastAst as ExpandableStringExpressionAst;
            var constantString = lastAst as StringConstantExpressionAst;
            if (constantString == null && expandableString == null) { return null; }

            string strValue = constantString != null ? constantString.Value : expandableString.Value;

            // Check for switch case completion on $PSBoundParameters.Keys
            completionContext.WordToComplete = strValue;
            var switchCaseResult = CompleteAgainstSwitchCaseCondition(completionContext);
            if (switchCaseResult != null && switchCaseResult.Count > 0)
            {
                return switchCaseResult;
            }

            // Check for $PSBoundParameters access patterns (ContainsKey, indexer, Remove)
            var psBoundResult = CompleteAgainstPSBoundParametersAccess(completionContext);
            if (psBoundResult != null && psBoundResult.Count > 0)
            {
                return psBoundResult;
            }

            bool shouldContinue;
            List<CompletionResult> result = GetResultForEnumPropertyValueOfDSCResource(completionContext, strValue, ref replacementIndex, ref replacementLength, out shouldContinue);
            if (!shouldContinue || (result != null && result.Count > 0))
            {
                return result;
            }

            var commandElementAst = lastAst as CommandElementAst;
            string wordToComplete =
                CompletionCompleters.ConcatenateStringPathArguments(commandElementAst, string.Empty, completionContext);

            if (wordToComplete != null)
            {
                completionContext.WordToComplete = wordToComplete;

                // Handle scenarios like this: cd 'c:\windows\win'<tab>
                if (lastAst.Parent is CommandAst || lastAst.Parent is CommandParameterAst)
                {
                    result = CompletionCompleters.CompleteCommandArgument(completionContext);
                    replacementIndex = completionContext.ReplacementIndex;
                    replacementLength = completionContext.ReplacementLength;
                }
                // Handle scenarios like this: "c:\wind"<tab>. Treat the StringLiteral/StringExpandable as path/command
                else
                {
                    // Handle path/commandname completion for quoted string
                    result = new List<CompletionResult>(CompletionCompleters.CompleteFilename(completionContext));

                    // Try command name completion only if the text contains '-'
                    if (wordToComplete.Contains('-'))
                    {
                        var commandNameResult = CompletionCompleters.CompleteCommand(completionContext);
                        if (commandNameResult != null && commandNameResult.Count > 0)
                        {
                            result.AddRange(commandNameResult);
                        }
                    }
                }
            }

            return result;
        }

        /// <summary>
        /// Find the configuration statement contains current cursor.
        /// </summary>
        /// <param name="cursorPosition"></param>
        /// <param name="ast"></param>
        /// <param name="keywordAst"></param>
        /// <returns></returns>
        private static ConfigurationDefinitionAst GetAncestorConfigurationAstAndKeywordAst(
            IScriptPosition cursorPosition,
            Ast ast,
            out DynamicKeywordStatementAst keywordAst)
        {
            ConfigurationDefinitionAst configureAst = Ast.GetAncestorConfigurationDefinitionAstAndDynamicKeywordStatementAst(ast, out keywordAst);
            // Find the configuration statement contains current cursor
            // Note: cursorPosition.Offset < configureAst.Extent.EndOffset means cursor locates inside the configuration
            //       cursorPosition.Offset = configureAst.Extent.EndOffset means cursor locates at the end of the configuration
            while (configureAst != null && cursorPosition.Offset > configureAst.Extent.EndOffset)
            {
                configureAst = Ast.GetAncestorAst<ConfigurationDefinitionAst>(configureAst.Parent);
            }

            return configureAst;
        }

        /// <summary>
        /// Generate auto complete results for identifier within configuration.
        /// Results are generated based on DynamicKeywords matches given identifier.
        /// For example, following "Fi" matches "File", and "Us" matches "User"
        ///
        ///     Configuration
        ///     {
        ///         Fi^
        ///         Node("TargetMachine")
        ///         {
        ///             Us^
        ///         }
        ///     }
        /// </summary>
        /// <param name="completionContext"></param>
        /// <param name="configureAst"></param>
        /// <param name="keywordAst"></param>
        /// <param name="matched"></param>
        /// <returns></returns>
        private static List<CompletionResult> GetResultForIdentifierInConfiguration(
            CompletionContext completionContext,
            ConfigurationDefinitionAst configureAst,
            DynamicKeywordStatementAst keywordAst,
            out bool matched)
        {
            List<CompletionResult> results = null;
            matched = false;

            IEnumerable<DynamicKeyword> keywords = configureAst.DefinedKeywords.Where(
                k => // Node is special case, legal in both Resource and Meta configuration
                    string.Equals(k.Keyword, @"Node", StringComparison.OrdinalIgnoreCase) ||
                    (
                        // Check compatibility between Resource and Configuration Type
                        k.IsCompatibleWithConfigurationType(configureAst.ConfigurationType) &&
                        !DynamicKeyword.IsHiddenKeyword(k.Keyword) &&
                        !k.IsReservedKeyword
                    )
            );

            if (keywordAst != null && completionContext.CursorPosition.Offset < keywordAst.Extent.EndOffset)
                keywords = keywordAst.Keyword.GetAllowedKeywords(keywords);

            if (keywords != null && keywords.Any())
            {
                string commandName = (completionContext.WordToComplete ?? string.Empty) + "*";
                var wildcardPattern = WildcardPattern.Get(commandName, WildcardOptions.IgnoreCase | WildcardOptions.CultureInvariant);

                // Filter by name
                var matchedResults = keywords.Where(k => wildcardPattern.IsMatch(k.Keyword));
                if (matchedResults == null || !matchedResults.Any())
                {
                    // Fallback to all legal keywords in the configuration statement
                    matchedResults = keywords;
                }
                else
                {
                    matched = true;
                }

                foreach (var keyword in matchedResults)
                {
                    string usageString = string.Empty;
                    ICrossPlatformDsc dscSubsystem = SubsystemManager.GetSubsystem<ICrossPlatformDsc>();
                    if (dscSubsystem != null)
                    {
                        usageString = dscSubsystem.GetDSCResourceUsageString(keyword);
                    }
                    else
                    {
                        usageString = Microsoft.PowerShell.DesiredStateConfiguration.Internal.DscClassCache.GetDSCResourceUsageString(keyword);
                    }

                    results ??= new List<CompletionResult>();

                    results.Add(new CompletionResult(
                        keyword.Keyword,
                        keyword.Keyword,
                        CompletionResultType.DynamicKeyword,
                        usageString));
                }
            }

            return results;
        }

        private static List<CompletionResult> GetResultForIdentifier(CompletionContext completionContext, ref int replacementIndex, ref int replacementLength)
        {
            List<CompletionResult> result = null;
            var tokenAtCursor = completionContext.TokenAtCursor;
            var lastAst = completionContext.RelatedAsts.Last();

            var tokenAtCursorText = tokenAtCursor.Text;
            completionContext.WordToComplete = tokenAtCursorText;

            // Check for switch case completion on $PSBoundParameters.Keys
            var switchCaseResult = CompleteAgainstSwitchCaseCondition(completionContext);
            if (switchCaseResult != null && switchCaseResult.Count > 0)
            {
                return switchCaseResult;
            }

            // Check for $PSBoundParameters access patterns (ContainsKey, indexer, Remove)
            var psBoundResult = CompleteAgainstPSBoundParametersAccess(completionContext);
            if (psBoundResult != null && psBoundResult.Count > 0)
            {
                return psBoundResult;
            }

            if (lastAst.Parent is BreakStatementAst || lastAst.Parent is ContinueStatementAst)
            {
                return CompleteLoopLabel(completionContext);
            }

            var strConst = lastAst as StringConstantExpressionAst;
            if (strConst != null)
            {
                if (strConst.Value.Equals("$", StringComparison.Ordinal))
                {
                    completionContext.WordToComplete = string.Empty;
                    return CompletionCompleters.CompleteVariable(completionContext);
                }
                else
                {
                    UsingStatementAst usingState = strConst.Parent as UsingStatementAst;
                    if (usingState != null)
                    {
                        completionContext.ReplacementIndex = strConst.Extent.StartOffset;
                        completionContext.ReplacementLength = strConst.Extent.EndOffset - replacementIndex;
                        completionContext.WordToComplete = strConst.Extent.Text;
                        switch (usingState.UsingStatementKind)
                        {
                            case UsingStatementKind.Assembly:
                                HashSet<string> assemblyExtensions = new(StringComparer.OrdinalIgnoreCase)
                                {
                                    StringLiterals.PowerShellILAssemblyExtension
                                };
                                return CompletionCompleters.CompleteFilename(completionContext, containerOnly: false, assemblyExtensions).ToList();

                            case UsingStatementKind.Command:
                                break;
                            case UsingStatementKind.Module:
                                var moduleExtensions = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
                                {
                                    StringLiterals.PowerShellModuleFileExtension,
                                    StringLiterals.PowerShellDataFileExtension,
                                    StringLiterals.PowerShellNgenAssemblyExtension,
                                    StringLiterals.PowerShellILAssemblyExtension,
                                    StringLiterals.PowerShellILExecutableExtension,
                                    StringLiterals.PowerShellCmdletizationFileExtension
                                };
                                result = CompletionCompleters.CompleteFilename(completionContext, false, moduleExtensions).ToList();
                                if (completionContext.WordToComplete.IndexOfAny(Utils.Separators.DirectoryOrDrive) != -1)
                                {
                                    // The partial input is a path, then we don't iterate modules under $ENV:PSModulePath
                                    return result;
                                }

                                var moduleResults = CompletionCompleters.CompleteModuleName(completionContext, false);
                                if (moduleResults != null && moduleResults.Count > 0)
                                    result.AddRange(moduleResults);
                                return result;
                            case UsingStatementKind.Namespace:
                                result = CompletionCompleters.CompleteNamespace(completionContext);
                                return result;
                            case UsingStatementKind.Type:
                                break;
                            default:
                                throw new ArgumentOutOfRangeException("UsingStatementKind");
                        }
                    }
                }
            }

            if (completionContext.TokenAtCursor.TokenFlags == TokenFlags.MemberName)
            {
                if (lastAst is NamedAttributeArgumentAst || lastAst.Parent is NamedAttributeArgumentAst)
                {
                    result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                }
                else if (lastAst is VariableExpressionAst && lastAst.Parent is ParameterAst paramAst && paramAst.Attributes.Count > 0)
                {
                    foreach (AttributeBaseAst attribute in paramAst.Attributes)
                    {
                        if (IsCursorWithinOrJustAfterExtent(completionContext.CursorPosition, attribute.Extent))
                        {
                            result = GetResultForAttributeArgument(completionContext, ref replacementIndex, ref replacementLength);
                            break;
                        }
                    }
                }

                if (result is not null)
                {
                    return result;
                }
            }

            if ((tokenAtCursor.TokenFlags & TokenFlags.CommandName) != 0)
            {
                // Handle completion for a path with variable, such as: $PSHOME\ty<tab>
                if (completionContext.RelatedAsts.Count > 0 && completionContext.RelatedAsts[0] is ScriptBlockAst)
                {
                    Ast cursorAst = completionContext.RelatedAsts[0].FindAll(
                        ast => ast.Extent.EndOffset <= tokenAtCursor.Extent.StartOffset
                            && ast.Extent is not EmptyScriptExtent,
                        searchNestedScriptBlocks: true).LastOrDefault();

                    if (cursorAst is not null)
                    {
                        if (cursorAst.Extent.EndOffset == tokenAtCursor.Extent.StartOffset)
                        {
                            if (tokenAtCursorText.AsSpan().IndexOfAny('\\', '/') == 0)
                            {
                                string wordToComplete =
                                    CompletionCompleters.ConcatenateStringPathArguments(cursorAst as CommandElementAst, tokenAtCursorText, completionContext);
                                if (wordToComplete != null)
                                {
                                    completionContext.WordToComplete = wordToComplete;
                                    result = new List<CompletionResult>(CompletionCompleters.CompleteFilename(completionContext));
                                    if (result.Count > 0)
                                    {
                                        replacementIndex = cursorAst.Extent.StartScriptPosition.Offset;
                                        replacementLength += cursorAst.Extent.Text.Length;
                                    }

                                    return result;
                                }
                                else
                                {
                                    var variableAst = cursorAst as VariableExpressionAst;
                                    string fullPath = variableAst != null
                                        ? CompletionCompleters.CombineVariableWithPartialPath(
                                            variableAst: variableAst,
                                            extraText: tokenAtCursorText,
                                            executionContext: completionContext.ExecutionContext)
                                        : null;

                                    if (fullPath == null) { return result; }

                                    // Continue trying the filename/commandname completion for scenarios like this: $aa\d<tab>
                                    completionContext.WordToComplete = fullPath;
                                    replacementIndex = cursorAst.Extent.StartScriptPosition.Offset;
                                    replacementLength += cursorAst.Extent.Text.Length;

                                    completionContext.ReplacementIndex = replacementIndex;
                                    completionContext.ReplacementLength = replacementLength;
                                }
                            }
                            // Continue trying the filename/commandname completion for scenarios like this: $aa[get-<tab>
                            else if (cursorAst is not ErrorExpressionAst || cursorAst.Parent is not IndexExpressionAst)
                            {
                                return result;
                            }
                        }

                        if (cursorAst.Parent is IndexExpressionAst indexExpression && indexExpression.Index is ErrorExpressionAst)
                        {
                            if (completionContext.WordToComplete.EndsWith(']'))
                            {
                                completionContext.WordToComplete = completionContext.WordToComplete.Remove(completionContext.WordToComplete.Length - 1);
                            }

                            // Handles index expression with unquoted word like: $PSVersionTable[psver<Tab>]
                            return CompletionCompleters.CompleteIndexExpression(completionContext, indexExpression.Target);
                        }
                    }
                }

                // Handle the StringExpandableToken;
                var strToken = tokenAtCursor as StringExpandableToken;
                if (strToken != null && strToken.NestedTokens != null && strConst != null)
                {
                    try
                    {
                        string expandedString = null;
                        var expandableStringAst = new ExpandableStringExpressionAst(strConst.Extent, strConst.Value, StringConstantType.BareWord);
                        if (CompletionCompleters.IsPathSafelyExpandable(expandableStringAst: expandableStringAst,
                                                                        extraText: string.Empty,
                                                                        executionContext: completionContext.ExecutionContext,
                                                                        expandedString: out expandedString))
                        {
                            completionContext.WordToComplete = expandedString;
                        }
                        else
                        {
                            return result;
                        }
                    }
                    catch (Exception)
                    {
                        return result;
                    }
                }

                //
                // Handle completion of DSC resources within Configuration
                //
                DynamicKeywordStatementAst keywordAst;
                ConfigurationDefinitionAst configureAst = GetAncestorConfigurationAstAndKeywordAst(completionContext.CursorPosition, lastAst, out keywordAst);
                bool matched = false;
                List<CompletionResult> keywordResult = null;
                if (configureAst != null)
                {
                    // Current token is within ConfigurationDefinitionAst or DynamicKeywordStatementAst
                    keywordResult = GetResultForIdentifierInConfiguration(completionContext, configureAst, keywordAst, out matched);
                }

                // Handle the file completion before command name completion
                result = CompleteFileNameAsCommand(completionContext);
                // Handle the command name completion
                var commandNameResult = CompletionCompleters.CompleteCommand(completionContext);

                if (commandNameResult != null && commandNameResult.Count > 0)
                {
                    result.AddRange(commandNameResult);
                }

                if (matched && keywordResult != null)
                {
                    result.InsertRange(0, keywordResult);
                }
                else if (!matched && keywordResult != null && commandNameResult.Count == 0)
                {
                    result.AddRange(keywordResult);
                }

                return result;
            }

            var isSingleDash = tokenAtCursorText.Length == 1 && tokenAtCursorText[0].IsDash();
            var isDoubleDash = tokenAtCursorText.Length == 2 && tokenAtCursorText[0].IsDash() && tokenAtCursorText[1].IsDash();
            var isParentCommandOrDynamicKeyword = (lastAst.Parent is CommandAst || lastAst.Parent is DynamicKeywordStatementAst);
            if ((isSingleDash || isDoubleDash) && isParentCommandOrDynamicKeyword)
            {
                // When it's the content of a quoted string, we only handle variable/member completion
                if (isSingleDash)
                {
                    var res = CompletionCompleters.CompleteCommandParameter(completionContext);
                    if (res.Count != 0)
                    {
                        return res;
                    }
                }

                return CompletionCompleters.CompleteCommandArgument(completionContext);
            }

            TokenKind memberOperator = TokenKind.Unknown;
            bool isMemberCompletion = lastAst.Parent is MemberExpressionAst;
            bool isStatic = false;
            if (isMemberCompletion)
            {
                var currentExpression = (MemberExpressionAst)lastAst.Parent;
                // Handles following scenario with an incomplete member access token at the end of the statement:
                // [System.IO.FileInfo]::new<Tab>().Directory.BaseName.Length.
                // Traverses up the expressions until it finds one under at the cursor
                while (currentExpression.Extent.EndOffset >= completionContext.CursorPosition.Offset
                    && currentExpression.Expression is MemberExpressionAst memberExpression
                    && memberExpression.Member.Extent.EndOffset >= completionContext.CursorPosition.Offset)
                {
                    currentExpression = memberExpression;
                }

                isStatic = currentExpression.Static;
            }

            bool isWildcard = false;

            if (!isMemberCompletion)
            {
                // Still might be member completion, something like: echo $member.
                // We need to know if the previous element before the token is adjacent because
                // we don't have a MemberExpressionAst, we might have 2 command arguments.

                if (tokenAtCursorText.Equals(TokenKind.Dot.Text(), StringComparison.Ordinal))
                {
                    memberOperator = TokenKind.Dot;
                    isMemberCompletion = true;
                }
                else if (tokenAtCursorText.Equals(TokenKind.ColonColon.Text(), StringComparison.Ordinal))
                {
                    memberOperator = TokenKind.ColonColon;
                    isMemberCompletion = true;
                }
                else if (tokenAtCursor.Kind.Equals(TokenKind.Multiply) && lastAst is BinaryExpressionAst)
                {
                    // Handle member completion with wildcard(wildcard is at the end): $a.p*
                    var binaryExpressionAst = (BinaryExpressionAst)lastAst;
                    var memberExpressionAst = binaryExpressionAst.Left as MemberExpressionAst;
                    var errorPosition = binaryExpressionAst.ErrorPosition;

                    if (memberExpressionAst != null && binaryExpressionAst.Operator == TokenKind.Multiply &&
                        errorPosition.StartOffset == memberExpressionAst.Member.Extent.EndOffset)
                    {
                        isStatic = memberExpressionAst.Static;
                        memberOperator = isStatic ? TokenKind.ColonColon : TokenKind.Dot;
                        isMemberCompletion = true;
                        isWildcard = true;

                        // Member completion will add back the '*', so pretend it wasn't there, at least from the "related asts" point of view,
                        // but add the member expression that we are really completing.
                        completionContext.RelatedAsts.Remove(binaryExpressionAst);
                        completionContext.RelatedAsts.Add(memberExpressionAst);

                        var memberAst = memberExpressionAst.Member as StringConstantExpressionAst;
                        if (memberAst != null)
                        {
                            replacementIndex = memberAst.Extent.StartScriptPosition.Offset;
                            replacementLength += memberAst.Extent.Text.Length;
                        }
                    }
                }
            }

            if (isMemberCompletion)
            {
                result = CompletionCompleters.CompleteMember(completionContext, @static: (isStatic || memberOperator == TokenKind.ColonColon), ref replacementLength);

                // If the last token was just a '.', we tried to complete members.  That may
                // have failed because it wasn't really an attempt to complete a member, in
                // which case we should try to complete as an argument.
                if (result.Count > 0)
                {
                    if (!isWildcard && memberOperator != TokenKind.Unknown)
                    {
                        replacementIndex += tokenAtCursorText.Length;
                        replacementLength = 0;
                    }

                    return result;
                }
            }

            if (lastAst.Parent is HashtableAst)
            {
                result = CompletionCompleters.CompleteHashtableKey(completionContext, (HashtableAst)lastAst.Parent);
                if (result != null && result.Count > 0)
                {
                    return result;
                }
            }

            bool needFileCompletion = false;
            if (lastAst.Parent is FileRedirectionAst || CompleteAgainstSwitchFile(lastAst, completionContext.TokenBeforeCursor))
            {
                string wordToComplete =
                    CompletionCompleters.ConcatenateStringPathArguments(lastAst as CommandElementAst, string.Empty, completionContext);
                if (wordToComplete != null)
                {
                    needFileCompletion = true;
                    completionContext.WordToComplete = wordToComplete;
                }
            }
            else if (tokenAtCursorText.AsSpan().IndexOfAny('\\', '/') == 0)
            {
                var command = lastAst.Parent as CommandBaseAst;
                if (command != null && command.Redirections.Count > 0)
                {
                    var fileRedirection = command.Redirections[0] as FileRedirectionAst;
                    if (fileRedirection != null &&
                        fileRedirection.Extent.EndLineNumber == lastAst.Extent.StartLineNumber &&
                        fileRedirection.Extent.EndColumnNumber == lastAst.Extent.StartColumnNumber)
                    {
                        string wordToComplete =
                            CompletionCompleters.ConcatenateStringPathArguments(fileRedirection.Location, tokenAtCursorText, completionContext);

                        if (wordToComplete != null)
                        {
                            needFileCompletion = true;
                            completionContext.WordToComplete = wordToComplete;
                            replacementIndex = fileRedirection.Location.Extent.StartScriptPosition.Offset;
                            replacementLength += fileRedirection.Location.Extent.EndScriptPosition.Offset - replacementIndex;

                            completionContext.ReplacementIndex = replacementIndex;
                            completionContext.ReplacementLength = replacementLength;
                        }
                    }
                }
            }

            if (needFileCompletion)
            {
                return new List<CompletionResult>(CompletionCompleters.CompleteFilename(completionContext));
            }
            else
            {
                string wordToComplete =
                    CompletionCompleters.ConcatenateStringPathArguments(lastAst as CommandElementAst, string.Empty, completionContext);
                if (wordToComplete != null)
                {
                    completionContext.WordToComplete = wordToComplete;
                }
            }

            result = CompletionCompleters.CompleteCommandArgument(completionContext);
            replacementIndex = completionContext.ReplacementIndex;
            replacementLength = completionContext.ReplacementLength;

            return result;
        }

        private static List<CompletionResult> GetResultForAttributeArgument(CompletionContext completionContext, ref int replacementIndex, ref int replacementLength)
        {
            // Attribute member arguments
            Type attributeType = null;
            string argName = string.Empty;
            Ast argAst = completionContext.RelatedAsts.Find(static ast => ast is NamedAttributeArgumentAst);
            AttributeAst attAst;
            if (argAst is NamedAttributeArgumentAst namedArgAst)
            {
                attAst = (AttributeAst)namedArgAst.Parent;
                attributeType = attAst.TypeName.GetReflectionAttributeType();
                argName = namedArgAst.ArgumentName;
                replacementIndex = namedArgAst.Extent.StartOffset;
                replacementLength = argName.Length;
            }
            else
            {
                Ast astAtt = completionContext.RelatedAsts.Find(static ast => ast is AttributeAst);
                attAst = astAtt as AttributeAst;
                if (attAst is not null)
                {
                    attributeType = attAst.TypeName.GetReflectionAttributeType();
                }
            }

            if (attributeType is not null)
            {
                int cursorPosition = completionContext.CursorPosition.Offset;
                var existingArguments = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
                foreach (var namedArgument in attAst.NamedArguments)
                {
                    if (cursorPosition < namedArgument.Extent.StartOffset || cursorPosition > namedArgument.Extent.EndOffset)
                    {
                        existingArguments.Add(namedArgument.ArgumentName);
                    }
                }

                PropertyInfo[] propertyInfos = attributeType.GetProperties(BindingFlags.Public | BindingFlags.Instance);
                List<CompletionResult> result = new List<CompletionResult>();
                foreach (PropertyInfo property in propertyInfos)
                {
                    // Ignore getter-only properties and properties that have already been set.
                    if (!property.CanWrite || existingArguments.Contains(property.Name))
                    {
                        continue;
                    }

                    if (property.Name.StartsWith(argName, StringComparison.OrdinalIgnoreCase))
                    {
                        result.Add(new CompletionResult(property.Name, property.Name, CompletionResultType.Property,
                            property.PropertyType.ToString() + " " + property.Name));
                    }
                }

                return result;
            }

            return null;
        }

        /// <summary>
        /// Complete file name as command.
        /// </summary>
        /// <param name="completionContext"></param>
        /// <returns></returns>
        private static List<CompletionResult> CompleteFileNameAsCommand(CompletionContext completionContext)
        {
            var addAmpersandIfNecessary = CompletionCompleters.IsAmpersandNeeded(completionContext, true);
            var result = new List<CompletionResult>();
            var clearLiteralPathsKey = false;

            if (completionContext.Options == null)
            {
                completionContext.Options = new Hashtable { { "LiteralPaths", true } };
            }
            else if (!completionContext.Options.ContainsKey("LiteralPaths"))
            {
                // Dont escape '[',']','`' when the file name is treated as command name
                completionContext.Options.Add("LiteralPaths", true);
                clearLiteralPathsKey = true;
            }

            try
            {
                var fileNameResult = CompletionCompleters.CompleteFilename(completionContext);
                foreach (var entry in fileNameResult)
                {
                    // Add '&' to file names that are quoted
                    var completionText = entry.CompletionText;
                    var len = completionText.Length;
                    if (addAmpersandIfNecessary && len > 2 && completionText[0].IsSingleQuote() && completionText[len - 1].IsSingleQuote())
                    {
                        completionText = "& " + completionText;
                        result.Add(new CompletionResult(completionText, entry.ListItemText, entry.ResultType, entry.ToolTip));
                    }
                    else
                    {
                        result.Add(entry);
                    }
                }
            }
            finally
            {
                if (clearLiteralPathsKey)
                    completionContext.Options.Remove("LiteralPaths");
            }

            return result;
        }

        /// <summary>
        /// Complete loop labels after labeled control flow statements such as Break and Continue.
        /// </summary>
        private static List<CompletionResult> CompleteLoopLabel(CompletionContext completionContext)
        {
            var result = new List<CompletionResult>();
            foreach (Ast ast in completionContext.RelatedAsts)
            {
                if (ast is LabeledStatementAst labeledStatement
                    && labeledStatement.Label is not null
                    && (completionContext.WordToComplete is null || labeledStatement.Label.StartsWith(completionContext.WordToComplete, StringComparison.OrdinalIgnoreCase)))
                {
                    result.Add(new CompletionResult(labeledStatement.Label, labeledStatement.Label, CompletionResultType.Text, labeledStatement.Extent.Text));
                }
                else if (ast is ErrorStatementAst errorStatement)
                {
                    // Handles incomplete do/switch loops (other labeled statements do not need this special treatment)
                    // The regex looks for the loopLabel of errorstatements that look like do/switch loops
                    // For example in ":Label do " it will find "Label".
                    var labelMatch = Regex.Match(errorStatement.Extent.Text, @"(?<=^:)\w+(?=\s+(do|switch)\b(?!-))", RegexOptions.IgnoreCase);
                    if (labelMatch.Success)
                    {
                        result.Add(new CompletionResult(labelMatch.Value, labelMatch.Value, CompletionResultType.Text, errorStatement.Extent.Text));
                    }
                }
            }

            if (result.Count == 0)
            {
                return null;
            }

            return result;
        }

        private static List<CompletionResult> CompleteUsingKeywords(int cursorOffset, Token[] tokens, ref int replacementIndex, ref int replacementLength)
        {
            var result = new List<CompletionResult>();
            Token tokenBeforeCursor = null;
            Token tokenAtCursor = null;

            for (int i = tokens.Length - 1; i >= 0; i--)
            {
                if (tokens[i].Extent.EndOffset < cursorOffset && tokens[i].Kind != TokenKind.LineContinuation)
                {
                    tokenBeforeCursor = tokens[i];
                    break;
                }
                else if (tokens[i].Extent.StartOffset <= cursorOffset && tokens[i].Extent.EndOffset >= cursorOffset && tokens[i].Kind != TokenKind.LineContinuation)
                {
                    tokenAtCursor = tokens[i];
                }
            }

            if (tokenBeforeCursor is not null && tokenBeforeCursor.Kind == TokenKind.Using)
            {
                string wordToComplete = null;
                if (tokenAtCursor is not null)
                {
                    replacementIndex = tokenAtCursor.Extent.StartOffset;
                    replacementLength = tokenAtCursor.Extent.Text.Length;
                    wordToComplete = tokenAtCursor.Text;
                }
                else
                {
                    replacementIndex = cursorOffset;
                    replacementLength = 0;
                }

                foreach (var keyword in s_usingKeywords)
                {
                    if (string.IsNullOrEmpty(wordToComplete) || keyword.StartsWith(wordToComplete, StringComparison.OrdinalIgnoreCase))
                    {
                        result.Add(new CompletionResult(keyword, keyword, CompletionResultType.Keyword, GetUsingKeywordToolTip(keyword)));
                    }
                }
            }

            if (result.Count > 0)
            {
                return result;
            }

            return null;
        }

        private static string GetUsingKeywordToolTip(string keyword)
        {
            switch (keyword)
            {
                case "assembly":
                    return TabCompletionStrings.AssemblyKeywordDescription;
                case "module":
                    return TabCompletionStrings.ModuleKeywordDescription;
                case "namespace":
                    return TabCompletionStrings.NamespaceKeywordDescription;
                case "type":
                    return TabCompletionStrings.TypeKeywordDescription;
                default:
                    return null;
            }
        }

        private static readonly string[] s_usingKeywords = new string[]
        {
            "assembly",
            "module",
            "namespace",
            "type"
        };
    }
}