summaryrefslogtreecommitdiff
path: root/lib/Travel/Status/DE/IRIS.pm
blob: 43b53137d4f6ea8606807f2c0b08f483c6db7e29 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
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
package Travel::Status::DE::IRIS;

use strict;
use warnings;
use 5.014;

no if $] >= 5.018, warnings => 'experimental::smartmatch';

our $VERSION = '1.72';

use Carp qw(confess cluck);
use DateTime;
use DateTime::Format::Strptime;
use List::Util qw(first);
use List::MoreUtils qw(uniq);
use List::UtilsBy qw(uniq_by);
use LWP::UserAgent;
use Travel::Status::DE::IRIS::Result;
use XML::LibXML;

sub try_load_xml {
	my ($xml) = @_;

	my $tree;

	eval { $tree = XML::LibXML->load_xml( string => $xml ) };

	if ($@) {
		return ( undef, $@ );
	}
	return ( $tree, undef );
}

# "station" parameter must be an EVA or DS100 ID.
sub new_p {
	my ( $class, %opt ) = @_;
	my $promise = $opt{promise}->new;

	if ( not $opt{station} ) {
		return $promise->reject('station flag must be passed');
	}

	my $self = $class->new( %opt, async => 1 );
	$self->{promise} = $opt{promise};

	my $lookahead_steps = int( $self->{lookahead} / 60 );
	if ( ( 60 - $self->{datetime}->minute ) < ( $self->{lookahead} % 60 ) ) {
		$lookahead_steps++;
	}
	my $lookbehind_steps = int( $self->{lookbehind} / 60 );
	if ( $self->{datetime}->minute < ( $self->{lookbehind} % 60 ) ) {
		$lookbehind_steps++;
	}

	my @candidates = $opt{get_station}( $opt{station} );

	if ( @candidates == 0 ) {
		return $promise->reject('station not found');
	}
	if ( @candidates >= 2 ) {
		return $promise->reject('station identifier is ambiguous');
	}

	$self->{station} = {
		ds100 => $candidates[0][0],
		name  => $candidates[0][1],
		uic   => $candidates[0][2],
	};
	$self->{related_stations} = [];

	my @queue = ( $self->{station}{uic} );
	my @related_reqs;
	my @related_stations;
	my %seen       = ( $self->{station}{uic} => 1 );
	my $iter_depth = 0;

	while ( @queue and $iter_depth < 12 and $opt{with_related} ) {
		my $eva = shift(@queue);
		$iter_depth++;
		for my $ref ( @{ $opt{meta}{$eva} // [] } ) {
			if ( not $seen{$ref} ) {
				push( @related_stations, $ref );
				$seen{$ref} = 1;
				push( @queue, $ref );
			}
		}
	}

	for my $eva (@related_stations) {
		@candidates = $opt{get_station}($eva);

		if ( @candidates == 1 ) {
			push(
				@{ $self->{related_stations} },
				{
					ds100 => $candidates[0][0],
					name  => $candidates[0][1],
					uic   => $candidates[0][2],
				}
			);
		}
	}

	my $dt_req = $self->{datetime}->clone;
	my @timetable_reqs
	  = ( $self->get_timetable_p( $self->{station}{uic}, $dt_req ) );

	for my $eva (@related_stations) {
		push( @timetable_reqs, $self->get_timetable_p( $eva, $dt_req ) );
	}

	for ( 1 .. $lookahead_steps ) {
		$dt_req->add( hours => 1 );
		push( @timetable_reqs,
			$self->get_timetable_p( $self->{station}{uic}, $dt_req ) );
		for my $eva (@related_stations) {
			push( @timetable_reqs, $self->get_timetable_p( $eva, $dt_req ) );
		}
	}

	$dt_req = $self->{datetime}->clone;
	for ( 1 .. $lookbehind_steps ) {
		$dt_req->subtract( hours => 1 );
		push( @timetable_reqs,
			$self->get_timetable_p( $self->{station}{uic}, $dt_req ) );
		for my $eva (@related_stations) {
			push( @timetable_reqs, $self->get_timetable_p( $eva, $dt_req ) );
		}
	}

	$self->{promise}->all(@timetable_reqs)->then(
		sub {
			my @realtime_reqs
			  = ( $self->get_realtime_p( $self->{station}{uic} ) );
			for my $eva (@related_stations) {
				push( @realtime_reqs, $self->get_realtime_p( $eva, $dt_req ) );
			}
			return $self->{promise}->all_settled(@realtime_reqs);
		}
	)->then(
		sub {
			my @realtime_results = @_;

			for my $realtime_result (@realtime_results) {
				if ( $realtime_result->{status} eq 'rejected' ) {
					$self->{warnstr} //= q{};
					$self->{warnstr}
					  .= "Realtime data request failed: $realtime_result->{reason}. ";
				}
			}

			$self->postprocess_results;
			$promise->resolve($self);
			return;
		}
	)->catch(
		sub {
			my ($err) = @_;
			$promise->reject($err);
			return;
		}
	)->wait;

	return $promise;
}

sub new {
	my ( $class, %opt ) = @_;

	if ( not $opt{station} ) {
		confess('station flag must be passed');
	}

	my $self = {
		datetime => $opt{datetime}
		  // DateTime->now( time_zone => 'Europe/Berlin' ),
		developer_mode => $opt{developer_mode},
		iris_base      => $opt{iris_base}
		  // 'https://iris.noncd.db.de/iris-tts/timetable',
		keep_transfers  => $opt{keep_transfers},
		lookahead       => $opt{lookahead}  // ( 2 * 60 ),
		lookbehind      => $opt{lookbehind} // ( 0 * 60 ),
		main_cache      => $opt{main_cache},
		rt_cache        => $opt{realtime_cache},
		serializable    => $opt{serializable},
		user_agent      => $opt{user_agent},
		with_related    => $opt{with_related},
		departure_by_id => {},
		strptime_obj => $opt{strptime_obj} // DateTime::Format::Strptime->new(
			pattern   => '%y%m%d%H%M',
			time_zone => 'Europe/Berlin',
		),
		xp_ar => XML::LibXML::XPathExpression->new('./ar'),
		xp_dp => XML::LibXML::XPathExpression->new('./dp'),
		xp_tl => XML::LibXML::XPathExpression->new('./tl'),

	};

	bless( $self, $class );

	my $lookahead_steps = int( $self->{lookahead} / 60 );
	if ( ( 60 - $self->{datetime}->minute ) < ( $self->{lookahead} % 60 ) ) {
		$lookahead_steps++;
	}
	my $lookbehind_steps = int( $self->{lookbehind} / 60 );
	if ( $self->{datetime}->minute < ( $self->{lookbehind} % 60 ) ) {
		$lookbehind_steps++;
	}

	if ( $opt{async} ) {
		return $self;
	}

	if ( not $self->{user_agent} ) {
		my %lwp_options = %{ $opt{lwp_options} // { timeout => 10 } };
		$self->{user_agent} = LWP::UserAgent->new(%lwp_options);
		$self->{user_agent}->env_proxy;
	}

	my ( $station, @related_stations ) = $self->get_station(
		name      => $opt{station},
		root      => 1,
		recursive => $opt{with_related},
	);

	$self->{station}          = $station;
	$self->{related_stations} = \@related_stations;

	for my $ref (@related_stations) {

       # We (the parent) perform transfer processing, so child requests must not
       # do it themselves. Otherwise, trains from child requests will be
       # processed twice and may be lost.
       # Similarly, child requests must not perform requests to related
       # stations -- we're already doing that right now.
		my $ref_status = Travel::Status::DE::IRIS->new(
			datetime       => $self->{datetime},
			developer_mode => $self->{developer_mode},
			iris_base      => $self->{iris_base},
			lookahead      => $self->{lookahead},
			lookbehind     => $self->{lookbehind},
			station        => $ref->{uic},
			main_cache     => $self->{main_cache},
			realtime_cache => $self->{rt_cache},
			strptime_obj   => $self->{strptime_obj},
			user_agent     => $self->{user_agent},
			keep_transfers => 1,
			with_related   => 0,
		);
		if ( not $ref_status->errstr ) {
			push( @{ $self->{results} }, $ref_status->results );
		}
	}

	if ( $self->{errstr} ) {
		return $self;
	}

	my $dt_req = $self->{datetime}->clone;
	$self->get_timetable( $self->{station}{uic}, $dt_req );
	for ( 1 .. $lookahead_steps ) {
		$dt_req->add( hours => 1 );
		$self->get_timetable( $self->{station}{uic}, $dt_req );
	}
	$dt_req = $self->{datetime}->clone;
	for ( 1 .. $lookbehind_steps ) {
		$dt_req->subtract( hours => 1 );
		$self->get_timetable( $self->{station}{uic}, $dt_req );
	}

	$self->get_realtime;

	$self->postprocess_results;

	return $self;
}

sub postprocess_results {
	my ($self) = @_;
	if ( not $self->{keep_transfers} ) {

		# tra (transfer?) indicates a train changing its ID, so there are two
		# results for the same train. Remove the departure-only trains from the
		# result set and merge them with their arrival-only counterpart.
		# This way, in case the arrival is available but the departure isn't,
		# nothing gets lost.
		my @merge_candidates
		  = grep { $_->transfer and $_->departure } @{ $self->{results} };
		@{ $self->{results} }
		  = grep { not( $_->transfer and $_->departure ) }
		  @{ $self->{results} };

		for my $transfer (@merge_candidates) {
			my $result
			  = first { $_->transfer and $_->transfer eq $transfer->train_id }
			  @{ $self->{results} };
			if ($result) {
				$result->merge_with_departure($transfer);
			}
		}
	}

	@{ $self->{results} } = grep {
		my $d = $_->departure     // $_->arrival;
		my $s = $_->sched_arrival // $_->sched_departure // $_->arrival // $d;
		$d = $d->subtract_datetime( $self->{datetime} );
		$s = $s->subtract_datetime( $self->{datetime} );
		not $d->is_negative and $s->in_units('minutes') < $self->{lookahead}
	} @{ $self->{results} };

	@{ $self->{results} }
	  = sort { $a->{epoch} <=> $b->{epoch} } @{ $self->{results} };

	# wings (different departures which are coupled as one train) contain
	# references to each other. therefore, they must be processed last.
	$self->create_wing_refs;

	# same goes for replacement refs (the <ref> tag in the fchg document)
	$self->create_replacement_refs;
}

sub get_with_cache_p {
	my ( $self, $cache, $url ) = @_;

	if ( $self->{developer_mode} ) {
		say "GET $url";
	}

	my $promise = $self->{promise}->new;

	if ($cache) {
		my $content = $cache->thaw($url);
		if ($content) {
			if ( $self->{developer_mode} ) {
				say '  cache hit';
			}
			return $promise->resolve($content);
		}
	}

	if ( $self->{developer_mode} ) {
		say '  cache miss';
	}

	my $res = $self->{user_agent}->get_p($url)->then(
		sub {
			my ($tx) = @_;
			if ( my $err = $tx->error ) {
				$promise->reject(
					"GET $url returned HTTP $err->{code} $err->{message}");
				return;
			}
			my $content = $tx->res->body;
			if ($cache) {
				$cache->freeze( $url, \$content );
			}
			$promise->resolve($content);
			return;
		}
	)->catch(
		sub {
			my ($err) = @_;
			$promise->reject($err);
			return;
		}
	)->wait;

	return $promise;
}

sub get_with_cache {
	my ( $self, $cache, $url ) = @_;

	if ( $self->{developer_mode} ) {
		say "GET $url";
	}

	if ($cache) {
		my $content = $cache->thaw($url);
		if ($content) {
			if ( $self->{developer_mode} ) {
				say '  cache hit';
			}
			return ( ${$content}, undef );
		}
	}

	if ( $self->{developer_mode} ) {
		say '  cache miss';
	}

	my $ua  = $self->{user_agent};
	my $res = $ua->get($url);

	if ( $res->is_error ) {
		return ( undef, $res->status_line );
	}
	my $content = $res->decoded_content;

	if ($cache) {
		$cache->freeze( $url, \$content );
	}

	return ( $content, undef );
}

sub get_station_p {
	my ( $self, %opt ) = @_;

	my $promise = $self->{promise}->new;
	my $station = $opt{name};

	$self->get_with_cache_p( $self->{main_cache},
		$self->{iris_base} . '/station/' . $station )->then(
		sub {
			my ($raw) = @_;
			my ( $xml_st, $xml_err ) = try_load_xml($raw);
			if ($xml_err) {
				$promise->reject('Failed to parse station data: Invalid XML');
				return;
			}
			my $station_node = ( $xml_st->findnodes('//station') )[0];

			if ( not $station_node ) {
				$promise->reject(
					"Station '$station' has no associated timetable");
				return;
			}
			$promise->resolve(
				{
					uic   => $station_node->getAttribute('eva'),
					name  => $station_node->getAttribute('name'),
					ds100 => $station_node->getAttribute('ds100'),
				}
			);
			return;
		}
	)->catch(
		sub {
			my ($err) = @_;
			$promise->reject($err);
			return;
		}
	)->wait;

	return $promise;
}

sub get_station {
	my ( $self, %opt ) = @_;

	my $iter_depth = 0;
	my @ret;
	my @queue = ( $opt{name} );

	# @seen holds station IDs which were already seen during recursive
	# 'meta' descent. This avoids infinite loops of 'meta' references.
	# Additionally, we use it to skip stations shat should not be referenced.
	# This includes Norddeich / Norddeich Mole (different stations commonly used
	# by identical trains with different departure times), and Essen-Dellwig /
	# Essen-Dellwig Ost (different stations used by different trains, but with
	# identical platform numbers).
	my @seen = ( 8007768, 8004449, 8001903, 8001904 );

	while ( @queue and $iter_depth < 12 ) {
		my $station = shift(@queue);
		push( @seen, $station );
		$iter_depth++;

		my ( $raw, $err )
		  = $self->get_with_cache( $self->{main_cache},
			$self->{iris_base} . '/station/' . $station );
		if ($err) {
			if ( $opt{root} ) {
				$self->{errstr} = "Failed to fetch station data: $err";
				return;
			}
			else {
				$self->{warnstr}
				  = "Failed to fetch station data for '$station': $err\n";
				next;
			}
		}

		my ( $xml_st, $xml_err ) = try_load_xml($raw);
		if ($xml_err) {
			$self->{errstr} = 'Failed to parse station data: Invalid XML';
			return;
		}

		my $station_node = ( $xml_st->findnodes('//station') )[0];

		if ( not $station_node ) {
			if ( $opt{root} ) {
				$self->{errstr}
				  = "Station '$station' has no associated timetable";
				return;
			}
			else {
				$self->{warnstr}
				  = "Station '$station' has no associated timetable";
				next;
			}
			next;
		}

		push( @seen, $station_node->getAttribute('eva') );

		if ( $station_node->getAttribute('name') =~ m{ ZOB} ) {

			# There are no departures from a ZOB ("Zentraler Omnibus-Bahnhof" /
			# Central Omnibus Station). Ignore it entirely.
			next;
		}

		if ( $station_node->getAttribute('ds100') =~ m{ ^ D \d+ $ }x ) {

			# This is an invalid DS100 code, at least from DB perspective.
			# So far it seems to refer to subway stations which do not have
			# IRIS departures.
			next;
		}

		push(
			@ret,
			{
				uic   => $station_node->getAttribute('eva'),
				name  => $station_node->getAttribute('name'),
				ds100 => $station_node->getAttribute('ds100'),
			}
		);

		if ( $self->{developer_mode} ) {
			printf( " -> %s (%s / %s)\n", @{ $ret[-1] }{qw{name uic ds100}} );
		}

		if ( $opt{recursive} and defined $station_node->getAttribute('meta') ) {
			my @refs
			  = uniq( split( m{ \| }x, $station_node->getAttribute('meta') ) );
			@refs = grep { not( $_ ~~ \@seen or $_ ~~ \@queue ) } @refs;
			push( @queue, @refs );
			$opt{root} = 0;
		}
	}

	if (@queue) {
		cluck(  "Reached $iter_depth iterations when tracking station IDs. "
			  . "This is probably a bug" );
	}

	@ret = uniq_by { $_->{uic} } @ret;

	return @ret;
}

sub add_result {
	my ( $self, $station_name, $station_uic, $s ) = @_;

	my $id   = $s->getAttribute('id');
	my $e_tl = ( $s->findnodes( $self->{xp_tl} ) )[0];
	my $e_ar = ( $s->findnodes( $self->{xp_ar} ) )[0];
	my $e_dp = ( $s->findnodes( $self->{xp_dp} ) )[0];

	if ( not $e_tl ) {
		return;
	}

	my %data = (
		raw_id       => $id,
		classes      => $e_tl->getAttribute('f'), # D N S F
		operator     => $e_tl->getAttribute('o'), # coded operator: 03/80/R2/...
		train_no     => $e_tl->getAttribute('n'), # dep number
		type         => $e_tl->getAttribute('c'), # S/ICE/ERB/...
		station      => $station_name,
		station_uic  => $station_uic + 0,         # UIC IDs are numbers
		strptime_obj => $self->{strptime_obj},

		#unknown_t    => $e_tl->getAttribute('t'),    # p
	);

	if ($e_ar) {
		$data{arrival_ts}  = $e_ar->getAttribute('pt');
		$data{line_no}     = $e_ar->getAttribute('l');
		$data{platform}    = $e_ar->getAttribute('pp');    # string, not number!
		$data{route_pre}   = $e_ar->getAttribute('ppth');
		$data{route_start} = $e_ar->getAttribute('pde');
		$data{transfer}    = $e_ar->getAttribute('tra');
		$data{arrival_hidden}   = $e_ar->getAttribute('hi');
		$data{arrival_wing_ids} = $e_ar->getAttribute('wings');
	}

	if ($e_dp) {
		$data{departure_ts} = $e_dp->getAttribute('pt');
		$data{line_no}      = $e_dp->getAttribute('l');
		$data{platform}     = $e_dp->getAttribute('pp');   # string, not number!
		$data{route_post}   = $e_dp->getAttribute('ppth');
		$data{route_end}    = $e_dp->getAttribute('pde');
		$data{transfer}     = $e_dp->getAttribute('tra');
		$data{departure_hidden}   = $e_dp->getAttribute('hi');
		$data{departure_wing_ids} = $e_dp->getAttribute('wings');
	}

	if ( $data{arrival_wing_ids} ) {
		$data{arrival_wing_ids} = [ split( /\|/, $data{arrival_wing_ids} ) ];
	}
	if ( $data{departure_wing_ids} ) {
		$data{departure_wing_ids}
		  = [ split( /\|/, $data{departure_wing_ids} ) ];
	}

	my $result = Travel::Status::DE::IRIS::Result->new(%data);

	# if scheduled departure and current departure are not within the
	# same hour, trains are reported twice. Don't add duplicates in
	# that case.
	if ( not $self->{departure_by_id}{$id} ) {
		push( @{ $self->{results} }, $result, );
		$self->{departure_by_id}{$id} = $result;
	}

	return $result;
}

sub get_timetable_p {
	my ( $self, $eva, $dt ) = @_;

	my $promise = $self->{promise}->new;

	$self->get_with_cache_p( $self->{main_cache},
		$dt->strftime( $self->{iris_base} . "/plan/${eva}/%y%m%d/%H" ) )->then(
		sub {
			my ($raw) = @_;
			my ( $xml, $xml_err ) = try_load_xml($raw);
			if ($xml_err) {
				$promise->reject(
					'Failed to parse a schedule part: Invalid XML');
				return;
			}
			my $station
			  = ( $xml->findnodes('/timetable') )[0]->getAttribute('station');

			for my $s ( $xml->findnodes('/timetable/s') ) {

				$self->add_result( $station, $eva, $s );
			}
			$promise->resolve;
			return;
		}
	)->catch(
		sub {
			my ($err) = @_;
			$promise->reject($err);
			return;
		}
	)->wait;
	return $promise;
}

sub get_timetable {
	my ( $self, $eva, $dt ) = @_;

	my ( $raw, $err )
	  = $self->get_with_cache( $self->{main_cache},
		$dt->strftime( $self->{iris_base} . "/plan/${eva}/%y%m%d/%H" ) );

	if ($err) {
		$self->{warnstr} = "Failed to fetch a schedule part: $err";
		return $self;
	}

	my ( $xml, $xml_err ) = try_load_xml($raw);

	if ($xml_err) {
		$self->{warnstr} = 'Failed to parse a schedule part: Invalid XML';
		return $self;
	}

	my $station = ( $xml->findnodes('/timetable') )[0]->getAttribute('station');

	for my $s ( $xml->findnodes('/timetable/s') ) {

		$self->add_result( $station, $eva, $s );
	}

	return $self;
}

sub get_realtime_p {
	my ( $self, $eva ) = @_;

	my $promise = $self->{promise}->new;

	$self->get_with_cache_p( $self->{rt_cache},
		$self->{iris_base} . "/fchg/${eva}" )->then(
		sub {
			my ($raw) = @_;
			my ( $xml, $xml_err ) = try_load_xml($raw);
			if ($xml_err) {
				$promise->reject(
					'Failed to parse a schedule part: Invalid XML');
				return;
			}
			$self->parse_realtime( $eva, $xml );
			$promise->resolve;
			return;
		}
	)->catch(
		sub {
			my ($err) = @_;
			$promise->reject("Failed to fetch realtime data: $err");
			return;
		}
	)->wait;
	return $promise;
}

sub get_realtime {
	my ($self) = @_;

	my $eva = $self->{station}{uic};

	my ( $raw, $err )
	  = $self->get_with_cache( $self->{rt_cache},
		$self->{iris_base} . "/fchg/${eva}" );

	if ($err) {
		$self->{warnstr} = "Failed to fetch realtime data: $err";
		return $self;
	}

	my ( $xml, $xml_err ) = try_load_xml($raw);

	if ($xml_err) {
		$self->{warnstr} = 'Failed to parse realtime data: Invalid XML';
		return $self;
	}

	$self->parse_realtime( $eva, $xml );
}

sub parse_realtime {
	my ( $self, $eva, $xml ) = @_;
	my $station = ( $xml->findnodes('/timetable') )[0]->getAttribute('station');

	for my $s ( $xml->findnodes('/timetable/s') ) {
		my $id     = $s->getAttribute('id');
		my $e_ar   = ( $s->findnodes( $self->{xp_ar} ) )[0];
		my $e_dp   = ( $s->findnodes( $self->{xp_dp} ) )[0];
		my @e_refs = $s->findnodes('./ref/tl');
		my @e_ms   = $s->findnodes('.//m');

		my %messages;

		my $result = $self->{departure_by_id}{$id};

		# add_result will return nothing if no ./tl node is present. The ./tl
		# check here is for optimization purposes.
		if ( not $result and ( $s->findnodes( $self->{xp_tl} ) )[0] ) {
			$result = $self->add_result( $station, $eva, $s );
			if ($result) {
				$result->set_unscheduled(1);
			}
		}
		if ( not $result ) {
			next;
		}

		if ( not $self->{serializable} ) {
			$result->set_realtime($s);
		}

		for my $e_m (@e_ms) {
			my $type  = $e_m->getAttribute('t');
			my $value = $e_m->getAttribute('c');
			my $msgid = $e_m->getAttribute('id');
			my $ts    = $e_m->getAttribute('ts');

           # 0 and 1 (with key "f") are related to canceled trains and
           # do not appear to hold information (or at least none we can access).
           # All observed cases of message ID 900 were related to bus
           # connections ("Anschlussbus wartet"). We can't access which bus
           # it refers to, so we don't show that either.
           # ID 1000 is a generic free text message, which (as we lack access
           # to the text itself) is not helpful either.
			if ( defined $value and $value > 1 and $value < 100 ) {
				$messages{$msgid} = [ $ts, $type, $value ];
			}
		}

		$result->set_messages(%messages);

		# note: A departure may also have a ./tl attribute. However, we do
		# not need to process it because it only matters for departures which
		# are not planned (or not in the plans we requested). However, in
		# those cases we already called add_result earlier, which reads ./tl
		# by itself.
		for my $e_ref (@e_refs) {
			$result->add_raw_ref(
				class    => $e_ref->getAttribute('f'),    # D N S F
				train_no => $e_ref->getAttribute('n'),    # dep number
				type     => $e_ref->getAttribute('c'),    # S/ICE/ERB/...
				line_no  => $e_ref->getAttribute('l'),    # 1 -> S1, ...

               #unknown_t => $e_ref->getAttribute('t'),    # p
               #unknown_o => $e_ref->getAttribute('o'),    # owner: 03/80/R2/...
               # TODO ps='a' -> rerouted and normally unscheduled train?
			);
		}
		if ($e_ar) {
			$result->set_ar(
				arrival_ts      => $e_ar->getAttribute('ct'),
				plan_arrival_ts => $e_ar->getAttribute('pt'),
				platform        => $e_ar->getAttribute('cp'),
				route_pre       => $e_ar->getAttribute('cpth'),
				sched_route_pre => $e_ar->getAttribute('ppth'),
				status          => $e_ar->getAttribute('cs'),
				status_since    => $e_ar->getAttribute('clt'),
				arrival_hidden  => $e_ar->getAttribute('hi'),

				# TODO ps='a' -> rerouted and normally unscheduled train?
			);
		}
		if ($e_dp) {
			$result->set_dp(
				departure_ts      => $e_dp->getAttribute('ct'),
				plan_departure_ts => $e_dp->getAttribute('pt'),
				platform          => $e_dp->getAttribute('cp'),
				route_post        => $e_dp->getAttribute('cpth'),
				sched_route_post  => $e_dp->getAttribute('ppth'),
				status            => $e_dp->getAttribute('cs'),
				departure_hidden  => $e_dp->getAttribute('hi'),
			);
		}

	}

	return $self;
}

sub get_result_by_id {
	my ( $self, $id ) = @_;

	my $res = first { $_->wing_id eq $id } @{ $self->{results} };
	return $res;
}

sub get_result_by_train {
	my ( $self, $type, $train_no ) = @_;

	my $res = first { $_->type eq $type and $_->train_no eq $train_no }
	  @{ $self->{results} };
	return $res;
}

sub create_wing_refs {
	my ($self) = @_;

	for my $r ( $self->results ) {
		if ( $r->{departure_wing_ids} ) {
			for my $wing_id ( @{ $r->{departure_wing_ids} } ) {
				my $wingref = $self->get_result_by_id($wing_id);
				if ($wingref) {
					$r->add_departure_wingref($wingref);
				}
			}
		}
		if ( $r->{arrival_wing_ids} ) {
			for my $wing_id ( @{ $r->{arrival_wing_ids} } ) {
				my $wingref = $self->get_result_by_id($wing_id);
				if ($wingref) {
					$r->add_arrival_wingref($wingref);
				}
			}
		}
	}

}

sub create_replacement_refs {
	my ($self) = @_;

	for my $r ( $self->results ) {
		for my $ref_hash ( @{ $r->{refs} // [] } ) {
			my $ref = $self->get_result_by_train( $ref_hash->{type},
				$ref_hash->{train_no} );
			if ($ref) {
				$r->add_reference($ref);
			}
		}
	}
}

sub station {
	my ($self) = @_;

	return $self->{station};
}

sub related_stations {
	my ($self) = @_;

	return @{ $self->{related_stations} };
}

sub errstr {
	my ($self) = @_;

	return $self->{errstr};
}

sub results {
	my ($self) = @_;

	return @{ $self->{results} // [] };
}

sub warnstr {
	my ($self) = @_;

	return $self->{warnstr};
}

1;

__END__

=head1 NAME

Travel::Status::DE::IRIS - Interface to IRIS based web departure monitors.

=head1 SYNOPSIS

Blocking variant:

    use Travel::Status::DE::IRIS;
    
    my $status = Travel::Status::DE::IRIS->new(station => "Essen Hbf");
    for my $r ($status->results) {
        printf(
            "%s %s +%-3d %10s -> %s\n",
            $r->date, $r->time, $r->delay || 0, $r->line, $r->destination
        );
    }

Non-blocking variant (EXPERIMENTAL):

    use Mojo::Promise;
    use Mojo::UserAgent;
    use Travel::Status::DE::IRIS;
    use Travel::Status::DE::IRIS::Stations;
    
    Travel::Status::DE::IRIS->new_p(station => "Essen Hbf",
            promise => 'Mojo::Promise', user_agent => Mojo::UserAgent->new,
            get_station => \&Travel::Status::DE::IRIS::Stations::get_station,
            meta => Travel::Status::DE::IRIS::Stations::get_meta())->then(sub {
        my ($status) = @_;
        for my $r ($status->results) {
            printf(
                "%s %s +%-3d %10s -> %s\n",
                $r->date, $r->time, $r->delay || 0, $r->line, $r->destination
            );
        }
    })->wait;

=head1 VERSION

version 1.72

=head1 DESCRIPTION

Travel::Status::DE::IRIS is an unofficial interface to IRIS based web
departure monitors such as
L<https://iris.noncd.db.de/wbt/js/index.html?typ=ab&style=qrab&bhf=EE&SecLang=&Zeilen=20&footer=0&disrupt=0>.

=head1 METHODS

=over

=item my $status = Travel::Status::DE::IRIS->new(I<%opt>)

Requests schedule and realtime data for a specific station at a specific
point in time. Returns a new Travel::Status::DE::IRIS object.

Arguments:

=over

=item B<datetime> => I<datetime-obj>

A DateTime(3pm) object specifying the point in time. Optional, defaults to the
current date and time.

=item B<iris_base> => I<url>

IRIS base url, defaults to C<< http://iris.noncd.db.de/iris-tts/timetable >>.

=item B<keep_transfers> => I<bool>

A train may change its ID and number at a station, indicating that although the
previous logical train ends here, the physical train will continue its journey
under a new number to a new destination. A notable example is the Berlin
Ringbahn, which travels round and round from Berlin SE<uuml>dkreuz to Berlin
SE<uuml>dkreuz. Each train number corresponds to a single revolution, but the
actual trains just keep going.

The IRIS backend returns two results for each transfer train: An arrival-only
result using the old ID (linked to the new one) and a departure-only result
using the new ID (linked to the old one). By default, this library merges these
into a single result with both arrival and departure time. Train number, ID,
and route are taken from the departure only. The original train ID and number
are available using the B<old_train_id> and B<old_train_no> accessors.

In case this is not desirable (e.g. because you intend to track a single
train to its destination station and do not want to implement special cases
for transfer trains), set B<keep_transfers> to a true value. In this case,
backend data will be reported as-is and transfer trains will not be merged.

=item B<lookahead> => I<int>

Compute only results which are scheduled less than I<int> minutes in the
future.
Default: 120 (2 hours).

Note that the DeutscheBahn IRIS backend only provides schedules up to four to
five hours into the future. So in most cases, setting this to a value above 240
minutes will have little effect. However, as the IRIS occasionally contains
unscheduled departures or qos messages known far in advance (e.g. 12 hours from
now), any non-negative integer is accepted.

=item B<lookbehind> => I<int>

Also check trains whose scheduled departure lies up to I<int> minutes in the
past. Default: 0.

This is useful when requesting departures shortly after a full hour. If,
for example, a train was scheduled to depart on 11:59 and has 5 minutes delay,
it will not be shown when requesting departures on or after 12:00 unless
B<lookbehind> is set to a value greater than zero.

Note that trains with significant delay (e.g. +30) may still be shown in this
case regardless of the setting of B<lookbehind>, since these receive special
treatment by the IRIS backend.

=item B<lwp_options> => I<\%hashref>

Passed on to C<< LWP::UserAgent->new >>. Defaults to C<< { timeout => 10 } >>,
you can use an empty hashref to unset the default.

=item B<main_cache> => I<$ojj>

A Cache::File(3pm) object used to cache station and timetable requests. Optional.

=item B<realtime_cache> => I<$ojj>

A Cache::File(3pm) object used to cache realtime data requests. Optional.

=item B<station> => I<stationcode>

Mandatory: Which station to return departures for. Note that this is not a
station name, but a station code, such as "EE" (for Essen Hbf) or "KA"
(for Aachen Hbf). See Travel::Status::DE::IRIS::Stations(3pm) for a
name to code mapping.

=item B<with_related> => I<bool>

Sometimes, Deutsche Bahn splits up major stations in the IRIS interface.  For
instance, "KE<ouml>ln Messe/Deutz" actually consists of "KE<ouml>ln
Messe/Deutz" (KKDZ), "KE<ouml>ln Messe/Deutz Gl. 9-10" (KKDZB) and "KE<ouml>ln
Messe/Deutz (tief)" (KKDT).

By default, Travel::Status::DE::IRIS only returns departures for the specified
station. When this option is set to a true value, it will also return
departures for all related stations.

=back

=item my $promise = Travel::Status::DE::IRIS->new_p(I<%opt>) (B<EXPERIMENTAL>)

Return a promise yielding a Travel::Status::DE::IRIS instance (C<< $status >>)
on success, or an error message (same as C<< $status->errstr >>) on failure.
This function is experimental and may be changed or remove without warning.

In addition to the arguments of B<new>, the following mandatory arguments must
be set:

=over

=item B<promise> => I<promises module>

Promises implementation to use for internal promises as well as B<new_p> return
value. Recommended: Mojo::Promise(3pm).

=item B<get_station> => I<get_station ref>

Reference to Travel::Status::DE::IRIS::Stations::get_station().

=item B<meta> => I<meta dict>

The dictionary returned by Travel::Status::DE::IRIS::Stations::get_meta().

=item B<user_agent> => I<user agent>

User agent instance to use for asynchronous requests. The object must support
promises (i.e., it must implement a C<< get_p >> function). Recommended:
Mojo::UserAgent(3pm).

=back

=item $status->errstr

In case of a fatal HTTP request or IRIS error, returns a string describing it.
Returns undef otherwise.

=item $status->related_stations

Returns a list of hashes describing related stations whose
arrivals/departures are included in B<results>. Only useful when setting
B<with_related> to a true value, see its documentation above for details.

Each hash contains the keys B<uic> (EVA number; often same as UIC station ID),
B<name> (station name), and B<ds100> (station code). Note that stations
returned by B<related_stations> are not necessarily known to
Travel::Status::DE::IRIS::Stations(3pm).

=item $status->results

Returns a list of Travel::Status::DE::IRIS::Result(3pm) objects, each one describing
one arrival and/or departure.

=item $status->warnstr

In case of a (probably) non-fatal HTTP request or IRIS error, returns a string
describing it.  Returns undef otherwise.

=back

=head1 DIAGNOSTICS

None.

=head1 DEPENDENCIES

=over

=item * DateTime(3pm)

=item * List::Util(3pm)

=item * LWP::UserAgent(3pm)

=item * XML::LibXML(3pm)

=back

=head1 BUGS AND LIMITATIONS

Some backend features are not yet exposed.

=head1 SEE ALSO

db-iris(1), Travel::Status::DE::IRIS::Result(3pm),
Travel::Status::DE::IRIS::Stations(3pm)

=head1 REPOSITORY

L<https://github.com/derf/Travel-Status-DE-IRIS>

=head1 AUTHOR

Copyright (C) 2013-2020 by Daniel Friesel E<lt>derf@finalrewind.orgE<gt>

=head1 LICENSE

This module is licensed under the same terms as Perl itself.