Function HandleStationRefit

src/economy.cpp:1475–1527

* Refit a vehicle in a station. * @param v Vehicle to be refitted. * @param consist_capleft Added cargo capacities in the consist. * @param st Station the vehicle is loading at. * @param next_station Possible next stations the vehicle can travel to. * @param new_cargo_type Target cargo for refit. */

 * @param new_cargo_type Target cargo for refit.
 */
static void HandleStationRefit(Vehicle *v, CargoArray &consist_capleft, Station *st, std::span<const StationID> next_station, CargoType new_cargo_type)
{
	Vehicle *v_start = v->GetFirstEnginePart();
	if (!IterateVehicleParts(v_start, IsEmptyAction())) return;

	Backup<CompanyID> cur_company(_current_company, v->owner);

	CargoTypes refit_mask = v->GetEngine()->info.refit_mask;

	/* Remove old capacity from consist capacity and collect refit mask. */
	IterateVehicleParts(v_start, PrepareRefitAction(consist_capleft, refit_mask));

	bool is_auto_refit = new_cargo_type == CARGO_AUTO_REFIT;
	if (is_auto_refit) {
		/* Get a refittable cargo type with waiting cargo for next_station or StationID::Invalid(). */
		new_cargo_type = v_start->cargo_type;
		for (CargoType cargo_type : SetCargoBitIterator(refit_mask)) {
			if (st->goods[cargo_type].HasData() && st->goods[cargo_type].GetData().cargo.HasCargoFor(next_station)) {
				/* Try to find out if auto-refitting would succeed. In case the refit is allowed,
				 * the returned refit capacity will be greater than zero. */
				auto [cc, refit_capacity, mail_capacity, cargo_capacities] = Command<CMD_REFIT_VEHICLE>::Do(DoCommandFlag::QueryCost, v_start->index, cargo_type, 0xFF, true, false, 1); // Auto-refit and only this vehicle including artic parts.
				/* Try to balance different loadable cargoes between parts of the consist, so that
				 * all of them can be loaded. Avoid a situation where all vehicles suddenly switch
				 * to the first loadable cargo for which there is only one packet. If the capacities
				 * are equal refit to the cargo of which most is available. This is important for
				 * consists of only a single vehicle as those will generally have a consist_capleft
				 * of 0 for all cargoes. */
				if (refit_capacity > 0 && (consist_capleft[cargo_type] < consist_capleft[new_cargo_type] ||
						(consist_capleft[cargo_type] == consist_capleft[new_cargo_type] &&
						st->goods[cargo_type].AvailableCount() > st->goods[new_cargo_type].AvailableCount()))) {
					new_cargo_type = cargo_type;
				}
			}
		}
	}

	/* Refit if given a valid cargo. */
	if (new_cargo_type < NUM_CARGO && new_cargo_type != v_start->cargo_type) {
		/* StationID::Invalid() because in the DT_MANUAL case that's correct and in the DT_(A)SYMMETRIC
		 * cases the next hop of the vehicle doesn't really tell us anything if the cargo had been
		 * "via any station" before reserving. We rather produce some more "any station" cargo than
		 * misrouting it. */
		IterateVehicleParts(v_start, ReturnCargoAction(st, StationID::Invalid()));
		CommandCost cost = std::get<0>(Command<CMD_REFIT_VEHICLE>::Do(DoCommandFlag::Execute, v_start->index, new_cargo_type, 0xFF, true, false, 1)); // Auto-refit and only this vehicle including artic parts.
		if (cost.Succeeded()) v->First()->profit_this_year -= cost.GetCost() << 8;
	}

	/* Add new capacity to consist capacity and reserve cargo */
	IterateVehicleParts(v_start, FinalizeRefitAction(consist_capleft, st, next_station,
			is_auto_refit || v->First()->current_order.IsFullLoadOrder()));

	cur_company.Restore();
}

/**
 * Test whether a vehicle can load cargo at a station even if exclusive transport rights are present.