/**
 * Are the tiles of the industry free?
 * @param tile                     Position to check.
 * @param it                       Industry tiles table.
 * @param itspec_index             The index of the itsepc to build/fund
 * @param type                     Type of the industry.
 * @param initial_random_bits      The random bits the industry is going to have after construction.
 * @param founder                  Industry founder
 * @param creation_type            The circumstances the industry is created under.
 * @param [out] custom_shape_check Perform custom check for the site.
 * @return Failed or succeeded command.
 */
static CommandCost CheckIfIndustryTilesAreFree(TileIndex tile, const IndustryTileTable *it, uint itspec_index, int type, uint16 initial_random_bits, Owner founder, IndustryAvailabilityCallType creation_type, bool *custom_shape_check = NULL)
{
	bool refused_slope = false;
	bool custom_shape = false;

	do {
		IndustryGfx gfx = GetTranslatedIndustryTileID(it->gfx);
		TileIndex cur_tile = TileAddWrap(tile, it->ti.x, it->ti.y);

		if (!IsValidTile(cur_tile)) {
			return_cmd_error(STR_ERROR_SITE_UNSUITABLE);
		}

		if (gfx == GFX_WATERTILE_SPECIALCHECK) {
			if (!IsTileType(cur_tile, MP_WATER) ||
					!IsTileFlat(cur_tile)) {
				return_cmd_error(STR_ERROR_SITE_UNSUITABLE);
			}
		} else {
			CommandCost ret = EnsureNoVehicleOnGround(cur_tile);
			if (ret.Failed()) return ret;
			if (IsBridgeAbove(cur_tile)) return_cmd_error(STR_ERROR_SITE_UNSUITABLE);

			const IndustryTileSpec *its = GetIndustryTileSpec(gfx);

			IndustryBehaviour ind_behav = GetIndustrySpec(type)->behaviour;

			/* Perform land/water check if not disabled */
			if (!HasBit(its->slopes_refused, 5) && ((HasTileWaterClass(cur_tile) && IsTileOnWater(cur_tile)) == !(ind_behav & INDUSTRYBEH_BUILT_ONWATER))) return_cmd_error(STR_ERROR_SITE_UNSUITABLE);

			if (HasBit(its->callback_mask, CBM_INDT_SHAPE_CHECK)) {
				custom_shape = true;
				CommandCost ret = PerformIndustryTileSlopeCheck(tile, cur_tile, its, type, gfx, itspec_index, initial_random_bits, founder, creation_type);
				if (ret.Failed()) return ret;
			} else {
				Slope tileh = GetTileSlope(cur_tile);
				refused_slope |= IsSlopeRefused(tileh, its->slopes_refused);
			}

			if ((ind_behav & (INDUSTRYBEH_ONLY_INTOWN | INDUSTRYBEH_TOWN1200_MORE)) || // Tile must be a house
					((ind_behav & INDUSTRYBEH_ONLY_NEARTOWN) && IsTileType(cur_tile, MP_HOUSE))) { // Tile is allowed to be a house (and it is a house)
				if (!IsTileType(cur_tile, MP_HOUSE)) {
					return_cmd_error(STR_ERROR_CAN_ONLY_BE_BUILT_IN_TOWNS);
				}

				/* Clear the tiles as OWNER_TOWN to not affect town rating, and to not clear protected buildings */
				Backup<CompanyByte> cur_company(_current_company, OWNER_TOWN, FILE_LINE);
				CommandCost ret = DoCommand(cur_tile, 0, 0, DC_NONE, CMD_LANDSCAPE_CLEAR);
				cur_company.Restore();

				if (ret.Failed()) return ret;
			} else {
				/* Clear the tiles, but do not affect town ratings */
				CommandCost ret = DoCommand(cur_tile, 0, 0, DC_AUTO | DC_NO_TEST_TOWN_RATING | DC_NO_MODIFY_TOWN_RATING, CMD_LANDSCAPE_CLEAR);

				if (ret.Failed()) {
					if (!(ind_behav & INDUSTRYBEH_BUILT_ONWATER)) return ret;

					if (!_settings_game.construction.build_on_competitor_canal) return ret;
					if (_settings_game.construction.build_on_competitor_canal && (ind_behav & INDUSTRYBEH_BUILT_ONWATER) && (IsTileType(cur_tile, MP_INDUSTRY) || _current_company >= MAX_COMPANIES)) return ret;
				}
			}
		}
	} while ((++it)->ti.x != -0x80);

	if (custom_shape_check != NULL) *custom_shape_check = custom_shape;

	/* It is almost impossible to have a fully flat land in TG, so what we
	 *  do is that we check if we can make the land flat later on. See
	 *  CheckIfCanLevelIndustryPlatform(). */
	if (!refused_slope || (_settings_game.game_creation.land_generator == LG_TERRAGENESIS && _generating_world && !custom_shape && !_ignore_restrictions)) {
		return CommandCost();
	}
	return_cmd_error(STR_ERROR_SITE_UNSUITABLE);
}