TBTR: Handle setting unit direction separately from refits

src/tbtr_template_vehicle_func.cpp

@@ -344,6 +344,20 @@ CommandCost CmdRefitTrainFromTemplate(Train *t, TemplateVehicle *tv, DoCommandFl
 
 		cost.AddCost(DoCommand(t->tile, t->index, tv->cargo_type | tv->cargo_subtype << 8 | (1 << 16) | (1 << 31), flags, cb));
 
+		// next
+		t = t->GetNextUnit();
+		tv = tv->GetNextUnit();
+	}
+	return cost;
+}
+
+// set unit direction of each vehicle in t as is in tv, assume t and tv contain the same types of vehicles
+CommandCost CmdSetTrainUnitDirectionFromTemplate(Train *t, TemplateVehicle *tv, DoCommandFlag flags)
+{
+	CommandCost cost(t->GetExpenseType(false));
+
+	while (t && tv) {
+		// refit t as tv
 		if (HasBit(t->flags, VRF_REVERSE_DIRECTION) != HasBit(tv->ctrl_flags, TVCF_REVERSED)) {
 			cost.AddCost(DoCommand(t->tile, t->index, true, flags, CMD_REVERSE_TRAIN_DIRECTION | CMD_MSG(STR_ERROR_CAN_T_REVERSE_DIRECTION_RAIL_VEHICLE)));
 		}

src/tbtr_template_vehicle_func.h

@@ -47,6 +47,7 @@ uint CountsTrainsNeedingTemplateReplacement(GroupID g_id, const TemplateVehicle
 CommandCost TestBuyAllTemplateVehiclesInChain(TemplateVehicle *tv, TileIndex tile);
 
 CommandCost CmdRefitTrainFromTemplate(Train *t, TemplateVehicle *tv, DoCommandFlag flags);
+CommandCost CmdSetTrainUnitDirectionFromTemplate(Train *t, TemplateVehicle *tv, DoCommandFlag flags);
 void BreakUpRemainders(Train *t);
 
 bool TemplateVehicleContainsEngineOfRailtype(const TemplateVehicle *tv, RailType type);

src/train_cmd.cpp

@@ -7357,9 +7357,6 @@ CommandCost CmdTemplateReplaceVehicle(TileIndex tile, DoCommandFlag flags, uint3
 				} else {
 					DoCommand(tile, new_part->index, store_refit_ct | (store_refit_csubt << 8) | (1 << 16) | (1 << 31), flags, GetCmdRefitVeh(new_part));
 				}
-				if (HasBit(new_part->flags, VRF_REVERSE_DIRECTION) != HasBit(cur_tmpl->ctrl_flags, TVCF_REVERSED)) {
-					DoCommand(tile, new_part->index, true, flags, CMD_REVERSE_TRAIN_DIRECTION | CMD_MSG(STR_ERROR_CAN_T_REVERSE_DIRECTION_RAIL_VEHICLE));
-				}
 			}
 
 		}
@@ -7378,6 +7375,8 @@ CommandCost CmdTemplateReplaceVehicle(TileIndex tile, DoCommandFlag flags, uint3
 		buy.AddCost(CmdRefitTrainFromTemplate(new_chain, tv, flags));
 	}
 
+	buy.AddCost(CmdSetTrainUnitDirectionFromTemplate(new_chain, tv, flags));
+
 	if (new_chain && remainder_chain) {
 		for (Train *ct = remainder_chain; ct != nullptr; ct = ct->Next()) {
 			TransferCargoForTrain(ct, new_chain);