Function CmdDeleteTown

src/town_cmd.cpp:3295–3384

* Delete a town (scenario editor or worldgen only). * @param flags Type of operation. * @param town_id Town ID to delete. * @return Empty cost or an error. */

 * @return Empty cost or an error.
 */
CommandCost CmdDeleteTown(DoCommandFlags flags, TownID town_id)
{
	if (_game_mode != GM_EDITOR && !_generating_world) return CMD_ERROR;
	Town *t = Town::GetIfValid(town_id);
	if (t == nullptr) return CMD_ERROR;

	/* Stations refer to towns. */
	for (const Station *st : Station::Iterate()) {
		if (st->town == t) {
			/* Non-oil rig stations are always a problem. */
			if (!st->facilities.Test(StationFacility::Airport) || st->airport.type != AT_OILRIG) return CMD_ERROR;
			/* We can only automatically delete oil rigs *if* there's no vehicle on them. */
			CommandCost ret = Command<CMD_LANDSCAPE_CLEAR>::Do(flags, st->airport.tile);
			if (ret.Failed()) return ret;
		}
	}

	/* Waypoints refer to towns. */
	for (const Waypoint *wp : Waypoint::Iterate()) {
		if (wp->town == t) return CMD_ERROR;
	}

	/* Depots refer to towns. */
	for (const Depot *d : Depot::Iterate()) {
		if (d->town == t) return CMD_ERROR;
	}

	/* Check all tiles for town ownership. First check for bridge tiles, as
	 * these do not directly have an owner so we need to check adjacent
	 * tiles. This won't work correctly in the same loop if the adjacent
	 * tile was already deleted earlier in the loop. */
	for (const auto current_tile : Map::Iterate()) {
		if (IsTileType(current_tile, MP_TUNNELBRIDGE) && TestTownOwnsBridge(current_tile, t)) {
			CommandCost ret = Command<CMD_LANDSCAPE_CLEAR>::Do(flags, current_tile);
			if (ret.Failed()) return ret;
		}
	}

	/* Check all remaining tiles for town ownership. */
	for (const auto current_tile : Map::Iterate()) {
		bool try_clear = false;
		switch (GetTileType(current_tile)) {
			case MP_ROAD:
				try_clear = HasTownOwnedRoad(current_tile) && GetTownIndex(current_tile) == t->index;
				break;

			case MP_HOUSE:
				try_clear = GetTownIndex(current_tile) == t->index;
				break;

			case MP_INDUSTRY:
				try_clear = Industry::GetByTile(current_tile)->town == t;
				break;

			case MP_OBJECT:
				if (Town::GetNumItems() == 1) {
					/* No towns will be left, remove it! */
					try_clear = true;