Function CmdAlterGroup

src/group_cmd.cpp:449–516

* Alter a group * @param flags type of operation * @param mode Operation to perform. * @param group_id GroupID * @param parent_id parent group index * @param text the new name or an empty string when resetting to the default * @return the cost of this operation or an error */

 * @return the cost of this operation or an error
 */
CommandCost CmdAlterGroup(DoCommandFlags flags, AlterGroupMode mode, GroupID group_id, GroupID parent_id, const std::string &text)
{
	Group *g = Group::GetIfValid(group_id);
	if (g == nullptr || g->owner != _current_company) return CMD_ERROR;

	if (mode == AlterGroupMode::Rename) {
		/* Rename group */
		bool reset = text.empty();

		if (!reset) {
			if (Utf8StringLength(text) >= MAX_LENGTH_GROUP_NAME_CHARS) return CMD_ERROR;
		}

		if (flags.Test(DoCommandFlag::Execute)) {
			/* Assign the new one */
			if (reset) {
				g->name.clear();
			} else {
				g->name = text;
			}
		}
	} else if (mode == AlterGroupMode::SetParent) {
		/* Do nothing if the parent group isn't actually changed. */
		if (g->parent == parent_id) return CommandCost();

		/* Set group parent */
		const Group *pg = Group::GetIfValid(parent_id);

		if (pg != nullptr) {
			if (pg->owner != _current_company) return CMD_ERROR;
			if (pg->vehicle_type != g->vehicle_type) return CMD_ERROR;

			/* Ensure request parent isn't child of group.
			 * This is the only place that infinite loops are prevented. */
			if (GroupIsInGroup(pg->index, g->index)) return CommandCost(STR_ERROR_GROUP_CAN_T_SET_PARENT_RECURSION);
		}

		if (flags.Test(DoCommandFlag::Execute)) {
			if (g->parent != GroupID::Invalid()) Group::Get(g->parent)->children.erase(g->index);
			g->parent = (pg == nullptr) ? GroupID::Invalid() : pg->index;
			if (g->parent != GroupID::Invalid()) Group::Get(g->parent)->children.insert(g->index);

			GroupStatistics::UpdateAutoreplace(g->owner);

			if (!g->livery.in_use.All({Livery::Flag::Primary, Livery::Flag::Secondary})) {
				/* Update livery with new parent's colours if either colour is default. */
				const Livery *livery = GetParentLivery(g);
				if (!g->livery.in_use.Test(Livery::Flag::Primary)) g->livery.colour1 = livery->colour1;
				if (!g->livery.in_use.Test(Livery::Flag::Secondary)) g->livery.colour2 = livery->colour2;

				PropagateChildLivery(g, true);
				MarkWholeScreenDirty();
			}
		}
	} else {
		return CMD_ERROR;
	}