Function CmdBuildVehicle

src/vehicle_cmd.cpp:100–225

* Build a vehicle. * @param flags for command * @param tile tile of depot where the vehicle is built * @param eid vehicle type being built. * @param use_free_vehicles use free vehicles when building the vehicle. * @param cargo refit cargo type. * @param client_id User * @return the cost of this operation + the new vehicle ID + the refitted capacity + the refitted mail capacity (aircraft) or

 * @return the cost of this operation + the new vehicle ID + the refitted capacity + the refitted mail capacity (aircraft) or an error
 */
std::tuple<CommandCost, VehicleID, uint, uint16_t, CargoArray> CmdBuildVehicle(DoCommandFlags flags, TileIndex tile, EngineID eid, bool use_free_vehicles, CargoType cargo, ClientID client_id)
{
	/* Elementary check for valid location. */
	if (!IsDepotTile(tile) || !IsTileOwner(tile, _current_company)) return { CMD_ERROR, VehicleID::Invalid(), 0, 0, {} };

	VehicleType type = GetDepotVehicleType(tile);

	/* Validate the engine type. */
	if (!IsEngineBuildable(eid, type, _current_company)) return { CommandCost(STR_ERROR_RAIL_VEHICLE_NOT_AVAILABLE + type), VehicleID::Invalid(), 0, 0, {} };

	/* Validate the cargo type. */
	if (cargo >= NUM_CARGO && IsValidCargoType(cargo)) return { CMD_ERROR, VehicleID::Invalid(), 0, 0, {} };

	const Engine *e = Engine::Get(eid);
	CommandCost value(EXPENSES_NEW_VEHICLES, e->GetCost());

	/* Engines without valid cargo should not be available */
	CargoType default_cargo = e->GetDefaultCargoType();
	if (!IsValidCargoType(default_cargo)) return { CMD_ERROR, VehicleID::Invalid(), 0, 0, {} };

	bool refitting = IsValidCargoType(cargo) && cargo != default_cargo;

	/* Check whether the number of vehicles we need to build can be built according to pool space. */
	uint num_vehicles;
	switch (type) {
		case VEH_TRAIN:    num_vehicles = (e->VehInfo<RailVehicleInfo>().railveh_type == RAILVEH_MULTIHEAD ? 2 : 1) + CountArticulatedParts(eid, false); break;
		case VEH_ROAD:     num_vehicles = 1 + CountArticulatedParts(eid, false); break;
		case VEH_SHIP:     num_vehicles = 1; break;
		case VEH_AIRCRAFT: num_vehicles = e->VehInfo<AircraftVehicleInfo>().subtype & AIR_CTOL ? 2 : 3; break;
		default: NOT_REACHED(); // Safe due to IsDepotTile()
	}
	if (!Vehicle::CanAllocateItem(num_vehicles)) return { CommandCost(STR_ERROR_TOO_MANY_VEHICLES_IN_GAME), VehicleID::Invalid(), 0, 0, {} };

	/* Check whether we can allocate a unit number. Autoreplace does not allocate
	 * an unit number as it will (always) reuse the one of the replaced vehicle
	 * and (train) wagons don't have an unit number in any scenario. */
	UnitID unit_num = (flags.Test(DoCommandFlag::QueryCost) || flags.Test(DoCommandFlag::AutoReplace) || (type == VEH_TRAIN && e->VehInfo<RailVehicleInfo>().railveh_type == RAILVEH_WAGON)) ? 0 : GetFreeUnitNumber(type);
	if (unit_num == UINT16_MAX) return { CommandCost(STR_ERROR_TOO_MANY_VEHICLES_IN_GAME), VehicleID::Invalid(), 0, 0, {} };

	/* If we are refitting we need to temporarily purchase the vehicle to be able to
	 * test it. */
	DoCommandFlags subflags = flags;
	if (refitting && !flags.Test(DoCommandFlag::Execute)) subflags.Set({DoCommandFlag::Execute, DoCommandFlag::AutoReplace});

	/* Vehicle construction needs random bits, so we have to save the random
	 * seeds to prevent desyncs. */
	SavedRandomSeeds saved_seeds;
	SaveRandomSeeds(&saved_seeds);

	Vehicle *v = nullptr;
	switch (type) {
		case VEH_TRAIN:    value.AddCost(CmdBuildRailVehicle(subflags, tile, e, &v)); break;
		case VEH_ROAD:     value.AddCost(CmdBuildRoadVehicle(subflags, tile, e, &v)); break;
		case VEH_SHIP:     value.AddCost(CmdBuildShip       (subflags, tile, e, &v)); break;
		case VEH_AIRCRAFT: value.AddCost(CmdBuildAircraft   (subflags, tile, e, &v)); break;
		default: NOT_REACHED(); // Safe due to IsDepotTile()
	}