summaryrefslogtreecommitdiff
path: root/src/engine.cpp
blob: 3e2a7d2d7c0be82688bb7d3168616b57b450fbc2 (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
/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file engine.cpp Base for all engine handling. */

#include "stdafx.h"
#include "company_func.h"
#include "command_func.h"
#include "news_func.h"
#include "aircraft.h"
#include "newgrf.h"
#include "newgrf_engine.h"
#include "strings_func.h"
#include "core/random_func.hpp"
#include "window_func.h"
#include "date_func.h"
#include "autoreplace_gui.h"
#include "string_func.h"
#include "ai/ai.hpp"
#include "core/pool_func.hpp"
#include "engine_gui.h"
#include "engine_func.h"
#include "engine_base.h"
#include "company_base.h"
#include "vehicle_func.h"
#include "articulated_vehicles.h"
#include "error.h"

#include "table/strings.h"
#include "table/engines.h"

#include "safeguards.h"

EnginePool _engine_pool("Engine");
INSTANTIATE_POOL_METHODS(Engine)

EngineOverrideManager _engine_mngr;

/**
 * Year that engine aging stops. Engines will not reduce in reliability
 * and no more engines will be introduced
 */
static Year _year_engine_aging_stops;

/** Number of engines of each vehicle type in original engine data */
const uint8 _engine_counts[4] = {
	lengthof(_orig_rail_vehicle_info),
	lengthof(_orig_road_vehicle_info),
	lengthof(_orig_ship_vehicle_info),
	lengthof(_orig_aircraft_vehicle_info),
};

/** Offset of the first engine of each vehicle type in original engine data */
const uint8 _engine_offsets[4] = {
	0,
	lengthof(_orig_rail_vehicle_info),
	lengthof(_orig_rail_vehicle_info) + lengthof(_orig_road_vehicle_info),
	lengthof(_orig_rail_vehicle_info) + lengthof(_orig_road_vehicle_info) + lengthof(_orig_ship_vehicle_info),
};

assert_compile(lengthof(_orig_rail_vehicle_info) + lengthof(_orig_road_vehicle_info) + lengthof(_orig_ship_vehicle_info) + lengthof(_orig_aircraft_vehicle_info) == lengthof(_orig_engine_info));

const uint EngineOverrideManager::NUM_DEFAULT_ENGINES = _engine_counts[VEH_TRAIN] + _engine_counts[VEH_ROAD] + _engine_counts[VEH_SHIP] + _engine_counts[VEH_AIRCRAFT];

Engine::Engine() :
	name(nullptr),
	overrides_count(0),
	overrides(nullptr)
{
}

Engine::Engine(VehicleType type, EngineID base)
{
	this->type = type;
	this->grf_prop.local_id = base;
	this->list_position = base;
	this->preview_company = INVALID_COMPANY;

	/* Check if this base engine is within the original engine data range */
	if (base >= _engine_counts[type]) {
		/* Set model life to maximum to make wagons available */
		this->info.base_life = 0xFF;
		/* Set road vehicle tractive effort to the default value */
		if (type == VEH_ROAD) this->u.road.tractive_effort = 0x4C;
		/* Aircraft must have CT_INVALID as default, as there is no property */
		if (type == VEH_AIRCRAFT) this->info.cargo_type = CT_INVALID;
		/* Set visual effect to the default value */
		switch (type) {
			case VEH_TRAIN: this->u.rail.visual_effect = VE_DEFAULT; break;
			case VEH_ROAD:  this->u.road.visual_effect = VE_DEFAULT; break;
			case VEH_SHIP:  this->u.ship.visual_effect = VE_DEFAULT; break;
			default: break; // The aircraft, disasters and especially visual effects have no NewGRF configured visual effects
		}
		/* Set cargo aging period to the default value. */
		this->info.cargo_age_period = CARGO_AGING_TICKS;
		return;
	}

	/* Copy the original engine info for this slot */
	this->info = _orig_engine_info[_engine_offsets[type] + base];

	/* Copy the original engine data for this slot */
	switch (type) {
		default: NOT_REACHED();

		case VEH_TRAIN:
			this->u.rail = _orig_rail_vehicle_info[base];
			this->original_image_index = this->u.rail.image_index;
			this->info.string_id = STR_VEHICLE_NAME_TRAIN_ENGINE_RAIL_KIRBY_PAUL_TANK_STEAM + base;

			/* Set the default model life of original wagons to "infinite" */
			if (this->u.rail.railveh_type == RAILVEH_WAGON) this->info.base_life = 0xFF;

			break;

		case VEH_ROAD:
			this->u.road = _orig_road_vehicle_info[base];
			this->original_image_index = this->u.road.image_index;
			this->info.string_id = STR_VEHICLE_NAME_ROAD_VEHICLE_MPS_REGAL_BUS + base;
			break;

		case VEH_SHIP:
			this->u.ship = _orig_ship_vehicle_info[base];
			this->original_image_index = this->u.ship.image_index;
			this->info.string_id = STR_VEHICLE_NAME_SHIP_MPS_OIL_TANKER + base;
			break;

		case VEH_AIRCRAFT:
			this->u.air = _orig_aircraft_vehicle_info[base];
			this->original_image_index = this->u.air.image_index;
			this->info.string_id = STR_VEHICLE_NAME_AIRCRAFT_SAMPSON_U52 + base;
			break;
	}
}

Engine::~Engine()
{
	UnloadWagonOverrides(this);
	free(this->name);
}

/**
 * Checks whether the engine is a valid (non-articulated part of an) engine.
 * @return true if enabled
 */
bool Engine::IsEnabled() const
{
	return this->info.string_id != STR_NEWGRF_INVALID_ENGINE && HasBit(this->info.climates, _settings_game.game_creation.landscape);
}

/**
 * Retrieve the GRF ID of the NewGRF the engine is tied to.
 * This is the GRF providing the Action 3.
 * @return GRF ID of the associated NewGRF.
 */
uint32 Engine::GetGRFID() const
{
	const GRFFile *file = this->GetGRF();
	return file == nullptr ? 0 : file->grfid;
}

/**
 * Determines whether an engine can carry something.
 * A vehicle cannot carry anything if its capacity is zero, or none of the possible cargoes is available in the climate.
 * @return true if the vehicle can carry something.
 */
bool Engine::CanCarryCargo() const
{
	/* For engines that can appear in a consist (i.e. rail vehicles and (articulated) road vehicles), a capacity
	 * of zero is a special case, to define the vehicle to not carry anything. The default cargotype is still used
	 * for livery selection etc.
	 * Note: Only the property is tested. A capacity callback returning 0 does not have the same effect.
	 */
	switch (this->type) {
		case VEH_TRAIN:
			if (this->u.rail.capacity == 0) return false;
			break;

		case VEH_ROAD:
			if (this->u.road.capacity == 0) return false;
			break;

		case VEH_SHIP:
		case VEH_AIRCRAFT:
			break;

		default: NOT_REACHED();
	}
	return this->GetDefaultCargoType() != CT_INVALID;
}


/**
 * Determines capacity of a given vehicle from scratch.
 * For aircraft the main capacity is determined. Mail might be present as well.
 * @param v Vehicle of interest; nullptr in purchase list
 * @param mail_capacity returns secondary cargo (mail) capacity of aircraft
 * @return Capacity
 */
uint Engine::DetermineCapacity(const Vehicle *v, uint16 *mail_capacity) const
{
	assert(v == nullptr || this->index == v->engine_type);
	if (mail_capacity != nullptr) *mail_capacity = 0;

	if (!this->CanCarryCargo()) return 0;

	bool new_multipliers = HasBit(this->info.misc_flags, EF_NO_DEFAULT_CARGO_MULTIPLIER);
	CargoID default_cargo = this->GetDefaultCargoType();
	CargoID cargo_type = (v != nullptr) ? v->cargo_type : default_cargo;

	if (mail_capacity != nullptr && this->type == VEH_AIRCRAFT && IsCargoInClass(cargo_type, CC_PASSENGERS)) {
		*mail_capacity = GetEngineProperty(this->index, PROP_AIRCRAFT_MAIL_CAPACITY, this->u.air.mail_capacity, v);
	}

	/* Check the refit capacity callback if we are not in the default configuration, or if we are using the new multiplier algorithm. */
	if (HasBit(this->info.callback_mask, CBM_VEHICLE_REFIT_CAPACITY) &&
			(new_multipliers || default_cargo != cargo_type || (v != nullptr && v->cargo_subtype != 0))) {
		uint16 callback = GetVehicleCallback(CBID_VEHICLE_REFIT_CAPACITY, 0, 0, this->index, v);
		if (callback != CALLBACK_FAILED) return callback;
	}

	/* Get capacity according to property resp. CB */
	uint capacity;
	uint extra_mail_cap = 0;
	switch (this->type) {
		case VEH_TRAIN:
			capacity = GetEngineProperty(this->index, PROP_TRAIN_CARGO_CAPACITY,        this->u.rail.capacity, v);

			/* In purchase list add the capacity of the second head. Always use the plain property for this. */
			if (v == nullptr && this->u.rail.railveh_type == RAILVEH_MULTIHEAD) capacity += this->u.rail.capacity;
			break;

		case VEH_ROAD:
			capacity = GetEngineProperty(this->index, PROP_ROADVEH_CARGO_CAPACITY,      this->u.road.capacity, v);
			break;

		case VEH_SHIP:
			capacity = GetEngineProperty(this->index, PROP_SHIP_CARGO_CAPACITY,         this->u.ship.capacity, v);
			break;

		case VEH_AIRCRAFT:
			capacity = GetEngineProperty(this->index, PROP_AIRCRAFT_PASSENGER_CAPACITY, this->u.air.passenger_capacity, v);
			if (!IsCargoInClass(cargo_type, CC_PASSENGERS)) {
				extra_mail_cap = GetEngineProperty(this->index, PROP_AIRCRAFT_MAIL_CAPACITY, this->u.air.mail_capacity, v);
			}
			if (!new_multipliers && cargo_type == CT_MAIL) return capacity + extra_mail_cap;
			default_cargo = CT_PASSENGERS; // Always use 'passengers' wrt. cargo multipliers
			break;

		default: NOT_REACHED();
	}

	if (!new_multipliers) {
		/* Use the passenger multiplier for mail as well */
		capacity += extra_mail_cap;
		extra_mail_cap = 0;
	}

	/* Apply multipliers depending on cargo- and vehicletype. */
	if (new_multipliers || (this->type != VEH_SHIP && default_cargo != cargo_type)) {
		uint16 default_multiplier = new_multipliers ? 0x100 : CargoSpec::Get(default_cargo)->multiplier;
		uint16 cargo_multiplier = CargoSpec::Get(cargo_type)->multiplier;
		capacity *= cargo_multiplier;
		if (extra_mail_cap > 0) {
			uint mail_multiplier = CargoSpec::Get(CT_MAIL)->multiplier;
			capacity += (default_multiplier * extra_mail_cap * cargo_multiplier + mail_multiplier / 2) / mail_multiplier;
		}
		capacity = (capacity + default_multiplier / 2) / default_multiplier;
	}

	return capacity;
}

/**
 * Return how much the running costs of this engine are.
 * @return Yearly running cost of the engine.
 */
Money Engine::GetRunningCost() const
{
	Price base_price;
	uint cost_factor;
	switch (this->type) {
		case VEH_ROAD:
			base_price = this->u.road.running_cost_class;
			if (base_price == INVALID_PRICE) return 0;
			cost_factor = GetEngineProperty(this->index, PROP_ROADVEH_RUNNING_COST_FACTOR, this->u.road.running_cost);
			break;

		case VEH_TRAIN:
			base_price = this->u.rail.running_cost_class;
			if (base_price == INVALID_PRICE) return 0;
			cost_factor = GetEngineProperty(this->index, PROP_TRAIN_RUNNING_COST_FACTOR, this->u.rail.running_cost);
			break;

		case VEH_SHIP:
			base_price = PR_RUNNING_SHIP;
			cost_factor = GetEngineProperty(this->index, PROP_SHIP_RUNNING_COST_FACTOR, this->u.ship.running_cost);
			break;

		case VEH_AIRCRAFT:
			base_price = PR_RUNNING_AIRCRAFT;
			cost_factor = GetEngineProperty(this->index, PROP_AIRCRAFT_RUNNING_COST_FACTOR, this->u.air.running_cost);
			break;

		default: NOT_REACHED();
	}

	return GetPrice(base_price, cost_factor, this->GetGRF(), -8);
}

/**
 * Return how much a new engine costs.
 * @return Cost of the engine.
 */
Money Engine::GetCost() const
{
	Price base_price;
	uint cost_factor;
	switch (this->type) {
		case VEH_ROAD:
			base_price = PR_BUILD_VEHICLE_ROAD;
			cost_factor = GetEngineProperty(this->index, PROP_ROADVEH_COST_FACTOR, this->u.road.cost_factor);
			break;

		case VEH_TRAIN:
			if (this->u.rail.railveh_type == RAILVEH_WAGON) {
				base_price = PR_BUILD_VEHICLE_WAGON;
				cost_factor = GetEngineProperty(this->index, PROP_TRAIN_COST_FACTOR, this->u.rail.cost_factor);
			} else {
				base_price = PR_BUILD_VEHICLE_TRAIN;
				cost_factor = GetEngineProperty(this->index, PROP_TRAIN_COST_FACTOR, this->u.rail.cost_factor);
			}
			break;

		case VEH_SHIP:
			base_price = PR_BUILD_VEHICLE_SHIP;
			cost_factor = GetEngineProperty(this->index, PROP_SHIP_COST_FACTOR, this->u.ship.cost_factor);
			break;

		case VEH_AIRCRAFT:
			base_price = PR_BUILD_VEHICLE_AIRCRAFT;
			cost_factor = GetEngineProperty(this->index, PROP_AIRCRAFT_COST_FACTOR, this->u.air.cost_factor);
			break;

		default: NOT_REACHED();
	}

	return GetPrice(base_price, cost_factor, this->GetGRF(), -8);
}

/**
 * Returns max speed of the engine for display purposes
 * @return max speed in km-ish/h
 */
uint Engine::GetDisplayMaxSpeed() const
{
	switch (this->type) {
		case VEH_TRAIN:
			return GetEngineProperty(this->index, PROP_TRAIN_SPEED, this->u.rail.max_speed);

		case VEH_ROAD: {
			uint max_speed = GetEngineProperty(this->index, PROP_ROADVEH_SPEED, 0);
			return (max_speed != 0) ? max_speed * 2 : this->u.road.max_speed / 2;
		}

		case VEH_SHIP:
			return GetEngineProperty(this->index, PROP_SHIP_SPEED, this->u.ship.max_speed) / 2;

		case VEH_AIRCRAFT: {
			uint max_speed = GetEngineProperty(this->index, PROP_AIRCRAFT_SPEED, 0);
			if (max_speed != 0) {
				return (max_speed * 128) / 10;
			}
			return this->u.air.max_speed;
		}

		default: NOT_REACHED();
	}
}

/**
 * Returns the power of the engine for display
 * and sorting purposes.
 * Only trains and road vehicles have power
 * @return power in display units hp
 */
uint Engine::GetPower() const
{
	/* Only trains and road vehicles have 'power'. */
	switch (this->type) {
		case VEH_TRAIN:
			return GetEngineProperty(this->index, PROP_TRAIN_POWER, this->u.rail.power);
		case VEH_ROAD:
			return GetEngineProperty(this->index, PROP_ROADVEH_POWER, this->u.road.power) * 10;

		default: NOT_REACHED();
	}
}

/**
 * Returns the weight of the engine for display purposes.
 * For dual-headed train-engines this is the weight of both heads
 * @return weight in display units metric tons
 */
uint Engine::GetDisplayWeight() const
{
	/* Only trains and road vehicles have 'weight'. */
	switch (this->type) {
		case VEH_TRAIN:
			return GetEngineProperty(this->index, PROP_TRAIN_WEIGHT, this->u.rail.weight) << (this->u.rail.railveh_type == RAILVEH_MULTIHEAD ? 1 : 0);
		case VEH_ROAD:
			return GetEngineProperty(this->index, PROP_ROADVEH_WEIGHT, this->u.road.weight) / 4;

		default: NOT_REACHED();
	}
}

/**
 * Returns the tractive effort of the engine for display purposes.
 * For dual-headed train-engines this is the tractive effort of both heads
 * @return tractive effort in display units kN
 */
uint Engine::GetDisplayMaxTractiveEffort() const
{
	/* Only trains and road vehicles have 'tractive effort'. */
	switch (this->type) {
		case VEH_TRAIN:
			return (GROUND_ACCELERATION * this->GetDisplayWeight() * GetEngineProperty(this->index, PROP_TRAIN_TRACTIVE_EFFORT, this->u.rail.tractive_effort)) / 256 / 1000;
		case VEH_ROAD:
			return (GROUND_ACCELERATION * this->GetDisplayWeight() * GetEngineProperty(this->index, PROP_ROADVEH_TRACTIVE_EFFORT, this->u.road.tractive_effort)) / 256 / 1000;

		default: NOT_REACHED();
	}
}

/**
 * Returns the vehicle's (not model's!) life length in days.
 * @return the life length
 */
Date Engine::GetLifeLengthInDays() const
{
	/* Assume leap years; this gives the player a bit more than the given amount of years, but never less. */
	return (this->info.lifelength + _settings_game.vehicle.extend_vehicle_life) * DAYS_IN_LEAP_YEAR;
}

/**
 * Get the range of an aircraft type.
 * @return Range of the aircraft type in tiles or 0 if unlimited range.
 */
uint16 Engine::GetRange() const
{
	switch (this->type) {
		case VEH_AIRCRAFT:
			return GetEngineProperty(this->index, PROP_AIRCRAFT_RANGE, this->u.air.max_range);

		default: NOT_REACHED();
	}
}

/**
 * Get the name of the aircraft type for display purposes.
 * @return Aircraft type string.
 */
StringID Engine::GetAircraftTypeText() const
{
	switch (this->type) {
		case VEH_AIRCRAFT:
			switch (this->u.air.subtype) {
				case AIR_HELI: return STR_LIVERY_HELICOPTER;
				case AIR_CTOL: return STR_LIVERY_SMALL_PLANE;
				case AIR_CTOL | AIR_FAST: return STR_LIVERY_LARGE_PLANE;
				default: NOT_REACHED();
			}

		default: NOT_REACHED();
	}
}

/**
 * Initializes the #EngineOverrideManager with the default engines.
 */
void EngineOverrideManager::ResetToDefaultMapping()
{
	this->clear();
	for (VehicleType type = VEH_TRAIN; type <= VEH_AIRCRAFT; type++) {
		for (uint internal_id = 0; internal_id < _engine_counts[type]; internal_id++) {
			/*C++17: EngineIDMapping &eid = */ this->emplace_back();
			EngineIDMapping &eid = this->back();
			eid.type            = type;
			eid.grfid           = INVALID_GRFID;
			eid.internal_id     = internal_id;
			eid.substitute_id   = internal_id;
		}
	}
}

/**
 * Looks up an EngineID in the EngineOverrideManager
 * @param type Vehicle type
 * @param grf_local_id The local id in the newgrf
 * @param grfid The GrfID that defines the scope of grf_local_id.
 *              If a newgrf overrides the engines of another newgrf, the "scope grfid" is the ID of the overridden newgrf.
 *              If dynnamic_engines is disabled, all newgrf share the same ID scope identified by INVALID_GRFID.
 * @return The engine ID if present, or INVALID_ENGINE if not.
 */
EngineID EngineOverrideManager::GetID(VehicleType type, uint16 grf_local_id, uint32 grfid)
{
	EngineID index = 0;
	for (const EngineIDMapping &eid : *this) {
		if (eid.type == type && eid.grfid == grfid && eid.internal_id == grf_local_id) {
			return index;
		}
		index++;
	}
	return INVALID_ENGINE;
}

/**
 * Tries to reset the engine mapping to match the current NewGRF configuration.
 * This is only possible when there are currently no vehicles in the game.
 * @return false if resetting failed due to present vehicles.
 */
bool EngineOverrideManager::ResetToCurrentNewGRFConfig()
{
	const Vehicle *v;
	FOR_ALL_VEHICLES(v) {
		if (IsCompanyBuildableVehicleType(v)) return false;
	}

	/* Reset the engines, they will get new EngineIDs */
	_engine_mngr.ResetToDefaultMapping();
	ReloadNewGRFData();

	return true;
}

/**
 * Initialise the engine pool with the data from the original vehicles.
 */
void SetupEngines()
{
	DeleteWindowByClass(WC_ENGINE_PREVIEW);
	_engine_pool.CleanPool();

	assert(_engine_mngr.size() >= _engine_mngr.NUM_DEFAULT_ENGINES);
	uint index = 0;
	for (const EngineIDMapping &eid : _engine_mngr) {
		/* Assert is safe; there won't be more than 256 original vehicles
		 * in any case, and we just cleaned the pool. */
		assert(Engine::CanAllocateItem());
		const Engine *e = new Engine(eid.type, eid.internal_id);
		assert(e->index == index);
		index++;
	}
}

void ShowEnginePreviewWindow(EngineID engine);

/**
 * Determine whether an engine type is a wagon (and not a loco).
 * @param index %Engine getting queried.
 * @return Whether the queried engine is a wagon.
 */
static bool IsWagon(EngineID index)
{
	const Engine *e = Engine::Get(index);
	return e->type == VEH_TRAIN && e->u.rail.railveh_type == RAILVEH_WAGON;
}

/**
 * Update #Engine::reliability and (if needed) update the engine GUIs.
 * @param e %Engine to update.
 */
static void CalcEngineReliability(Engine *e)
{
	uint age = e->age;

	/* Check for early retirement */
	if (e->company_avail != 0 && !_settings_game.vehicle.never_expire_vehicles && e->info.base_life != 0xFF) {
		int retire_early = e->info.retire_early;
		uint retire_early_max_age = max(0, e->duration_phase_1 + e->duration_phase_2 - retire_early * 12);
		if (retire_early != 0 && age >= retire_early_max_age) {
			/* Early retirement is enabled and we're past the date... */
			e->company_avail = 0;
			AddRemoveEngineFromAutoreplaceAndBuildWindows(e->type);
		}
	}

	if (age < e->duration_phase_1) {
		uint start = e->reliability_start;
		e->reliability = age * (e->reliability_max - start) / e->duration_phase_1 + start;
	} else if ((age -= e->duration_phase_1) < e->duration_phase_2 || _settings_game.vehicle.never_expire_vehicles || e->info.base_life == 0xFF) {
		/* We are at the peak of this engines life. It will have max reliability.
		 * This is also true if the engines never expire. They will not go bad over time */
		e->reliability = e->reliability_max;
	} else if ((age -= e->duration_phase_2) < e->duration_phase_3) {
		uint max = e->reliability_max;
		e->reliability = (int)age * (int)(e->reliability_final - max) / e->duration_phase_3 + max;
	} else {
		/* time's up for this engine.
		 * We will now completely retire this design */
		e->company_avail = 0;
		e->reliability = e->reliability_final;
		/* Kick this engine out of the lists */
		AddRemoveEngineFromAutoreplaceAndBuildWindows(e->type);
	}
	SetWindowClassesDirty(WC_BUILD_VEHICLE); // Update to show the new reliability
	SetWindowClassesDirty(WC_REPLACE_VEHICLE);
}

/** Compute the value for #_year_engine_aging_stops. */
void SetYearEngineAgingStops()
{
	/* Determine last engine aging year, default to 2050 as previously. */
	_year_engine_aging_stops = 2050;

	const Engine *e;
	FOR_ALL_ENGINES(e) {
		const EngineInfo *ei = &e->info;

		/* Exclude certain engines */
		if (!HasBit(ei->climates, _settings_game.game_creation.landscape)) continue;
		if (e->type == VEH_TRAIN && e->u.rail.railveh_type == RAILVEH_WAGON) continue;

		/* Base year ending date on half the model life */
		YearMonthDay ymd;
		ConvertDateToYMD(ei->base_intro + (ei->lifelength * DAYS_IN_LEAP_YEAR) / 2, &ymd);

		_year_engine_aging_stops = max(_year_engine_aging_stops, ymd.year);
	}
}

/**
 * Start/initialise one engine.
 * @param e The engine to initialise.
 * @param aging_date The date used for age calculations.
 */
void StartupOneEngine(Engine *e, Date aging_date)
{
	const EngineInfo *ei = &e->info;

	e->age = 0;
	e->flags = 0;
	e->company_avail = 0;
	e->company_hidden = 0;

	/* Don't randomise the start-date in the first two years after gamestart to ensure availability
	 * of engines in early starting games.
	 * Note: TTDP uses fixed 1922 */
	SavedRandomSeeds saved_seeds;
	SaveRandomSeeds(&saved_seeds);
	SetRandomSeed(_settings_game.game_creation.generation_seed ^
	              ei->base_intro ^
	              e->type ^
	              e->GetGRFID());
	uint32 r = Random();

	e->intro_date = ei->base_intro <= ConvertYMDToDate(_settings_game.game_creation.starting_year + 2, 0, 1) ? ei->base_intro : (Date)GB(r, 0, 9) + ei->base_intro;
	if (e->intro_date <= _date) {
		e->age = (aging_date - e->intro_date) >> 5;
		e->company_avail = (CompanyMask)-1;
		e->flags |= ENGINE_AVAILABLE;
	}

	e->reliability_start = GB(r, 16, 14) + 0x7AE0;
	r = Random();
	e->reliability_max   = GB(r,  0, 14) + 0xBFFF;
	e->reliability_final = GB(r, 16, 14) + 0x3FFF;

	r = Random();
	e->duration_phase_1 = GB(r, 0, 5) + 7;
	e->duration_phase_2 = GB(r, 5, 4) + ei->base_life * 12 - 96;
	e->duration_phase_3 = GB(r, 9, 7) + 120;

	e->reliability_spd_dec = ei->decay_speed << 2;

	RestoreRandomSeeds(saved_seeds);
	CalcEngineReliability(e);

	/* prevent certain engines from ever appearing. */
	if (!HasBit(ei->climates, _settings_game.game_creation.landscape)) {
		e->flags |= ENGINE_AVAILABLE;
		e->company_avail = 0;
	}
}

/**
 * Start/initialise all our engines. Must be called whenever there are changes
 * to the NewGRF config.
 */
void StartupEngines()
{
	Engine *e;
	/* Aging of vehicles stops, so account for that when starting late */
	const Date aging_date = min(_date, ConvertYMDToDate(_year_engine_aging_stops, 0, 1));

	FOR_ALL_ENGINES(e) {
		StartupOneEngine(e, aging_date);
	}

	/* Update the bitmasks for the vehicle lists */
	Company *c;
	FOR_ALL_COMPANIES(c) {
		c->avail_railtypes = GetCompanyRailtypes(c->index);
		c->avail_roadtypes = GetCompanyRoadtypes(c->index);
	}

	/* Invalidate any open purchase lists */
	InvalidateWindowClassesData(WC_BUILD_VEHICLE);
}

/**
 * Company \a company accepts engine \a eid for preview.
 * @param eid Engine being accepted (is under preview).
 * @param company Current company previewing the engine.
 */
static void AcceptEnginePreview(EngineID eid, CompanyID company)
{
	Engine *e = Engine::Get(eid);
	Company *c = Company::Get(company);

	SetBit(e->company_avail, company);
	if (e->type == VEH_TRAIN) {
		assert(e->u.rail.railtype < RAILTYPE_END);
		c->avail_railtypes = AddDateIntroducedRailTypes(c->avail_railtypes | GetRailTypeInfo(e->u.rail.railtype)->introduces_railtypes, _date);
	} else if (e->type == VEH_ROAD) {
		SetBit(c->avail_roadtypes, HasBit(e->info.misc_flags, EF_ROAD_TRAM) ? ROADTYPE_TRAM : ROADTYPE_ROAD);
	}

	e->preview_company = INVALID_COMPANY;
	e->preview_asked = (CompanyMask)-1;
	if (company == _local_company) {
		AddRemoveEngineFromAutoreplaceAndBuildWindows(e->type);
	}

	/* Update the toolbar. */
	if (e->type == VEH_ROAD) InvalidateWindowData(WC_BUILD_TOOLBAR, TRANSPORT_ROAD);
	if (e->type == VEH_SHIP) InvalidateWindowData(WC_BUILD_TOOLBAR, TRANSPORT_WATER);

	/* Notify preview window, that it might want to close.
	 * Note: We cannot directly close the window.
	 *       In singleplayer this function is called from the preview window, so
	 *       we have to use the GUI-scope scheduling of InvalidateWindowData.
	 */
	InvalidateWindowData(WC_ENGINE_PREVIEW, eid);
}

/**
 * Get the best company for an engine preview.
 * @param e Engine to preview.
 * @return Best company if it exists, #INVALID_COMPANY otherwise.
 */
static CompanyID GetPreviewCompany(Engine *e)
{
	CompanyID best_company = INVALID_COMPANY;

	/* For trains the cargomask has no useful meaning, since you can attach other wagons */
	CargoTypes cargomask = e->type != VEH_TRAIN ? GetUnionOfArticulatedRefitMasks(e->index, true) : ALL_CARGOTYPES;

	int32 best_hist = -1;
	const Company *c;
	FOR_ALL_COMPANIES(c) {
		if (c->block_preview == 0 && !HasBit(e->preview_asked, c->index) &&
				c->old_economy[0].performance_history > best_hist) {

			/* Check whether the company uses similar vehicles */
			Vehicle *v;
			FOR_ALL_VEHICLES(v) {
				if (v->owner != c->index || v->type != e->type) continue;
				if (!v->GetEngine()->CanCarryCargo() || !HasBit(cargomask, v->cargo_type)) continue;

				best_hist = c->old_economy[0].performance_history;
				best_company = c->index;
				break;
			}
		}
	}

	return best_company;
}

/**
 * Checks if a vehicle type is disabled for all/ai companies.
 * @param type The vehicle type which shall be checked.
 * @param ai If true, check if the type is disabled for AI companies, otherwise check if
 *           the vehicle type is disabled for human companies.
 * @return Whether or not a vehicle type is disabled.
 */
static bool IsVehicleTypeDisabled(VehicleType type, bool ai)
{
	switch (type) {
		case VEH_TRAIN:    return _settings_game.vehicle.max_trains == 0   || (ai && _settings_game.ai.ai_disable_veh_train);
		case VEH_ROAD:     return _settings_game.vehicle.max_roadveh == 0  || (ai && _settings_game.ai.ai_disable_veh_roadveh);
		case VEH_SHIP:     return _settings_game.vehicle.max_ships == 0    || (ai && _settings_game.ai.ai_disable_veh_ship);
		case VEH_AIRCRAFT: return _settings_game.vehicle.max_aircraft == 0 || (ai && _settings_game.ai.ai_disable_veh_aircraft);

		default: NOT_REACHED();
	}
}

/** Daily check to offer an exclusive engine preview to the companies. */
void EnginesDailyLoop()
{
	Company *c;
	FOR_ALL_COMPANIES(c) {
		c->avail_railtypes = AddDateIntroducedRailTypes(c->avail_railtypes, _date);
	}

	if (_cur_year >= _year_engine_aging_stops) return;

	Engine *e;
	FOR_ALL_ENGINES(e) {
		EngineID i = e->index;
		if (e->flags & ENGINE_EXCLUSIVE_PREVIEW) {
			if (e->preview_company != INVALID_COMPANY) {
				if (!--e->preview_wait) {
					DeleteWindowById(WC_ENGINE_PREVIEW, i);
					e->preview_company = INVALID_COMPANY;
				}
			} else if (CountBits(e->preview_asked) < MAX_COMPANIES) {
				e->preview_company = GetPreviewCompany(e);

				if (e->preview_company == INVALID_COMPANY) {
					e->preview_asked = (CompanyMask)-1;
					continue;
				}

				SetBit(e->preview_asked, e->preview_company);
				e->preview_wait = 20;
				/* AIs are intentionally not skipped for preview even if they cannot build a certain
				 * vehicle type. This is done to not give poor performing human companies an "unfair"
				 * boost that they wouldn't have gotten against other human companies. The check on
				 * the line below is just to make AIs not notice that they have a preview if they
				 * cannot build the vehicle. */
				if (!IsVehicleTypeDisabled(e->type, true)) AI::NewEvent(e->preview_company, new ScriptEventEnginePreview(i));
				if (IsInteractiveCompany(e->preview_company)) ShowEnginePreviewWindow(i);
			}
		}
	}
}

/**
 * Clear the 'hidden' flag for all engines of a new company.
 * @param cid Company being created.
 */
void ClearEnginesHiddenFlagOfCompany(CompanyID cid)
{
	Engine *e;
	FOR_ALL_ENGINES(e) {
		SB(e->company_hidden, cid, 1, 0);
	}
}

/**
 * Set the visibility of an engine.
 * @param tile Unused.
 * @param flags Operation to perform.
 * @param p1 Unused.
 * @param p2 Bit 31: 0=visible, 1=hidden, other bits for the #EngineID.
 * @param text Unused.
 * @return The cost of this operation or an error.
 */
CommandCost CmdSetVehicleVisibility(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
	Engine *e = Engine::GetIfValid(GB(p2, 0, 31));
	if (e == nullptr || _current_company >= MAX_COMPANIES) return CMD_ERROR;
	if (!IsEngineBuildable(e->index, e->type, _current_company)) return CMD_ERROR;

	if ((flags & DC_EXEC) != 0) {
		SB(e->company_hidden, _current_company, 1, GB(p2, 31, 1));
		AddRemoveEngineFromAutoreplaceAndBuildWindows(e->type);
	}

	return CommandCost();
}

/**
 * Accept an engine prototype. XXX - it is possible that the top-company
 * changes while you are waiting to accept the offer? Then it becomes invalid
 * @param tile unused
 * @param flags operation to perform
 * @param p1 engine-prototype offered
 * @param p2 unused
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdWantEnginePreview(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
	Engine *e = Engine::GetIfValid(p1);
	if (e == nullptr || !(e->flags & ENGINE_EXCLUSIVE_PREVIEW) || e->preview_company != _current_company) return CMD_ERROR;

	if (flags & DC_EXEC) AcceptEnginePreview(p1, _current_company);

	return CommandCost();
}

/**
 * An engine has become available for general use.
 * Also handle the exclusive engine preview contract.
 * @param e Engine generally available as of now.
 */
static void NewVehicleAvailable(Engine *e)
{
	Vehicle *v;
	Company *c;
	EngineID index = e->index;

	/* In case the company didn't build the vehicle during the intro period,
	 * prevent that company from getting future intro periods for a while. */
	if (e->flags & ENGINE_EXCLUSIVE_PREVIEW) {
		FOR_ALL_COMPANIES(c) {
			uint block_preview = c->block_preview;

			if (!HasBit(e->company_avail, c->index)) continue;

			/* We assume the user did NOT build it.. prove me wrong ;) */
			c->block_preview = 20;

			FOR_ALL_VEHICLES(v) {
				if (v->type == VEH_TRAIN || v->type == VEH_ROAD || v->type == VEH_SHIP ||
						(v->type == VEH_AIRCRAFT && Aircraft::From(v)->IsNormalAircraft())) {
					if (v->owner == c->index && v->engine_type == index) {
						/* The user did prove me wrong, so restore old value */
						c->block_preview = block_preview;
						break;
					}
				}
			}
		}
	}

	e->flags = (e->flags & ~ENGINE_EXCLUSIVE_PREVIEW) | ENGINE_AVAILABLE;
	AddRemoveEngineFromAutoreplaceAndBuildWindows(e->type);

	/* Now available for all companies */
	e->company_avail = (CompanyMask)-1;

	/* Do not introduce new rail wagons */
	if (IsWagon(index)) return;

	if (e->type == VEH_TRAIN) {
		/* maybe make another rail type available */
		RailType railtype = e->u.rail.railtype;
		assert(railtype < RAILTYPE_END);
		FOR_ALL_COMPANIES(c) c->avail_railtypes = AddDateIntroducedRailTypes(c->avail_railtypes | GetRailTypeInfo(e->u.rail.railtype)->introduces_railtypes, _date);
	} else if (e->type == VEH_ROAD) {
		/* maybe make another road type available */
		FOR_ALL_COMPANIES(c) SetBit(c->avail_roadtypes, HasBit(e->info.misc_flags, EF_ROAD_TRAM) ? ROADTYPE_TRAM : ROADTYPE_ROAD);
	}

	/* Only broadcast event if AIs are able to build this vehicle type. */
	if (!IsVehicleTypeDisabled(e->type, true)) AI::BroadcastNewEvent(new ScriptEventEngineAvailable(index));

	/* Only provide the "New Vehicle available" news paper entry, if engine can be built. */
	if (!IsVehicleTypeDisabled(e->type, false)) {
		SetDParam(0, GetEngineCategoryName(index));
		SetDParam(1, index);
		AddNewsItem(STR_NEWS_NEW_VEHICLE_NOW_AVAILABLE_WITH_TYPE, NT_NEW_VEHICLES, NF_VEHICLE, NR_ENGINE, index);
	}

	/* Update the toolbar. */
	if (e->type == VEH_ROAD) InvalidateWindowData(WC_BUILD_TOOLBAR, TRANSPORT_ROAD);
	if (e->type == VEH_SHIP) InvalidateWindowData(WC_BUILD_TOOLBAR, TRANSPORT_WATER);

	/* Close pending preview windows */
	DeleteWindowById(WC_ENGINE_PREVIEW, index);
}

/** Monthly update of the availability, reliability, and preview offers of the engines. */
void EnginesMonthlyLoop()
{
	if (_cur_year < _year_engine_aging_stops) {
		Engine *e;
		FOR_ALL_ENGINES(e) {
			/* Age the vehicle */
			if ((e->flags & ENGINE_AVAILABLE) && e->age != MAX_DAY) {
				e->age++;
				CalcEngineReliability(e);
			}

			/* Do not introduce invalid engines */
			if (!e->IsEnabled()) continue;

			if (!(e->flags & ENGINE_AVAILABLE) && _date >= (e->intro_date + DAYS_IN_YEAR)) {
				/* Introduce it to all companies */
				NewVehicleAvailable(e);
			} else if (!(e->flags & (ENGINE_AVAILABLE | ENGINE_EXCLUSIVE_PREVIEW)) && _date >= e->intro_date) {
				/* Introduction date has passed...
				 * Check if it is allowed to build this vehicle type at all
				 * based on the current game settings. If not, it does not
				 * make sense to show the preview dialog to any company. */
				if (IsVehicleTypeDisabled(e->type, false)) continue;

				/* Do not introduce new rail wagons */
				if (IsWagon(e->index)) continue;

				/* Show preview dialog to one of the companies. */
				e->flags |= ENGINE_EXCLUSIVE_PREVIEW;
				e->preview_company = INVALID_COMPANY;
				e->preview_asked = 0;
			}
		}

		InvalidateWindowClassesData(WC_BUILD_VEHICLE); // rebuild the purchase list (esp. when sorted by reliability)
	}
}

/**
 * Is \a name still free as name for an engine?
 * @param name New name of an engine.
 * @return \c false if the name is being used already, else \c true.
 */
static bool IsUniqueEngineName(const char *name)
{
	const Engine *e;

	FOR_ALL_ENGINES(e) {
		if (e->name != nullptr && strcmp(e->name, name) == 0) return false;
	}

	return true;
}

/**
 * Rename an engine.
 * @param tile unused
 * @param flags operation to perform
 * @param p1 engine ID to rename
 * @param p2 unused
 * @param text the new name or an empty string when resetting to the default
 * @return the cost of this operation or an error
 */
CommandCost CmdRenameEngine(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
	Engine *e = Engine::GetIfValid(p1);
	if (e == nullptr) return CMD_ERROR;

	bool reset = StrEmpty(text);

	if (!reset) {
		if (Utf8StringLength(text) >= MAX_LENGTH_ENGINE_NAME_CHARS) return CMD_ERROR;
		if (!IsUniqueEngineName(text)) return_cmd_error(STR_ERROR_NAME_MUST_BE_UNIQUE);
	}

	if (flags & DC_EXEC) {
		free(e->name);

		if (reset) {
			e->name = nullptr;
		} else {
			e->name = stredup(text);
		}

		MarkWholeScreenDirty();
	}

	return CommandCost();
}


/**
 * Check if an engine is buildable.
 * @param engine  index of the engine to check.
 * @param type    the type the engine should be.
 * @param company index of the company.
 * @return True if an engine is valid, of the specified type, and buildable by
 *              the given company.
 */
bool IsEngineBuildable(EngineID engine, VehicleType type, CompanyID company)
{
	const Engine *e = Engine::GetIfValid(engine);

	/* check if it's an engine that is in the engine array */
	if (e == nullptr) return false;

	/* check if it's an engine of specified type */
	if (e->type != type) return false;

	/* check if it's available ... */
	if (company == OWNER_DEITY) {
		/* ... for any company (preview does not count) */
		if (!(e->flags & ENGINE_AVAILABLE) || e->company_avail == 0) return false;
	} else {
		/* ... for this company */
		if (!HasBit(e->company_avail, company)) return false;
	}

	if (!e->IsEnabled()) return false;

	if (type == VEH_TRAIN && company != OWNER_DEITY) {
		/* Check if the rail type is available to this company */
		const Company *c = Company::Get(company);
		if (((GetRailTypeInfo(e->u.rail.railtype))->compatible_railtypes & c->avail_railtypes) == 0) return false;
	}

	return true;
}

/**
 * Check if an engine is refittable.
 * Note: Likely you want to use IsArticulatedVehicleRefittable().
 * @param engine index of the engine to check.
 * @return true if the engine is refittable.
 */
bool IsEngineRefittable(EngineID engine)
{
	const Engine *e = Engine::GetIfValid(engine);

	/* check if it's an engine that is in the engine array */
	if (e == nullptr) return false;

	if (!e->CanCarryCargo()) return false;

	const EngineInfo *ei = &e->info;
	if (ei->refit_mask == 0) return false;

	/* Are there suffixes?
	 * Note: This does not mean the suffixes are actually available for every consist at any time. */
	if (HasBit(ei->callback_mask, CBM_VEHICLE_CARGO_SUFFIX)) return true;

	/* Is there any cargo except the default cargo? */
	CargoID default_cargo = e->GetDefaultCargoType();
	CargoTypes default_cargo_mask = 0;
	SetBit(default_cargo_mask, default_cargo);
	return default_cargo != CT_INVALID && ei->refit_mask != default_cargo_mask;
}

/**
 * Check for engines that have an appropriate availability.
 */
void CheckEngines()
{
	const Engine *e;
	Date min_date = INT32_MAX;

	FOR_ALL_ENGINES(e) {
		if (!e->IsEnabled()) continue;

		/* We have an available engine... yay! */
		if ((e->flags & ENGINE_AVAILABLE) != 0 && e->company_avail != 0) return;

		/* Okay, try to find the earliest date. */
		min_date = min(min_date, e->info.base_intro);
	}

	if (min_date < INT32_MAX) {
		SetDParam(0, min_date);
		ShowErrorMessage(STR_ERROR_NO_VEHICLES_AVAILABLE_YET, STR_ERROR_NO_VEHICLES_AVAILABLE_YET_EXPLANATION, WL_WARNING);
	} else {
		ShowErrorMessage(STR_ERROR_NO_VEHICLES_AVAILABLE_AT_ALL, STR_ERROR_NO_VEHICLES_AVAILABLE_AT_ALL_EXPLANATION, WL_WARNING);
	}
}