Function CmdRemoveLongRoad

src/road_cmd.cpp:1063–1124

* Remove a long piece of road. * @param flags operation to perform * @param end_tile end tile of drag * @param start_tile start tile of drag * @param rt road type * @param axis direction * @param start_half start tile starts in the 2nd half of tile * @param end_half end tile starts in the 2nd half of tile (p2 & 2) * @return the cost of this operation or an error */

 * @return the cost of this operation or an error
 */
std::tuple<CommandCost, Money> CmdRemoveLongRoad(DoCommandFlags flags, TileIndex end_tile, TileIndex start_tile, RoadType rt, Axis axis, bool start_half, bool end_half)
{
	CommandCost cost(EXPENSES_CONSTRUCTION);

	if (start_tile >= Map::Size()) return { CMD_ERROR, 0 };
	if (!ValParamRoadType(rt) || !IsValidAxis(axis)) return { CMD_ERROR, 0 };

	/* Only drag in X or Y direction dictated by the direction variable */
	if (axis == AXIS_X && TileY(start_tile) != TileY(end_tile)) return { CMD_ERROR, 0 }; // x-axis
	if (axis == AXIS_Y && TileX(start_tile) != TileX(end_tile)) return { CMD_ERROR, 0 }; // y-axis

	/* Swap start and ending tile, also the half-tile drag vars. */
	if (start_tile > end_tile || (start_tile == end_tile && start_half)) {
		std::swap(start_tile, end_tile);
		std::swap(start_half, end_half);
	}

	Money money_available = GetAvailableMoneyForCommand();
	Money money_spent = 0;
	TileIndex tile = start_tile;
	CommandCost last_error = CMD_ERROR;
	bool had_success = false;
	/* Start tile is the small number. */
	for (;;) {
		RoadBits bits = AxisToRoadBits(axis);

		if (tile == end_tile && !end_half) bits &= ROAD_NW | ROAD_NE;
		if (tile == start_tile && start_half) bits &= ROAD_SE | ROAD_SW;

		/* try to remove the halves. */
		if (bits != 0) {
			RoadTramType rtt = GetRoadTramType(rt);
			CommandCost ret = RemoveRoad(tile, DoCommandFlags{flags}.Reset(DoCommandFlag::Execute), bits, rtt, true);
			if (ret.Succeeded()) {
				if (flags.Test(DoCommandFlag::Execute)) {
					money_spent += ret.GetCost();
					if (money_spent > 0 && money_spent > money_available) {
						return { cost, std::get<0>(Command<CMD_REMOVE_LONG_ROAD>::Do(DoCommandFlags{flags}.Reset(DoCommandFlag::Execute), end_tile, start_tile, rt, axis, start_half, end_half)).GetCost() };
					}
					RemoveRoad(tile, flags, bits, rtt, false);
				}
				cost.AddCost(ret.GetCost());
				had_success = true;
			} else {
				/* Some errors are more equal than others. */
				switch (last_error.GetErrorMessage()) {
					case STR_ERROR_OWNED_BY:
					case STR_ERROR_LOCAL_AUTHORITY_REFUSES_TO_ALLOW_THIS:
						break;
					default:
						last_error = std::move(ret);
				}
			}
		}

		if (tile == end_tile) break;

		tile += TileOffsByAxis(axis);