/**
 * Find the nearest hangar to v
 * INVALID_STATION is returned, if the company does not have any suitable
 * airports (like helipads only)
 * @param v vehicle looking for a hangar
 * @return the StationID if one is found, otherwise, INVALID_STATION
 */
static StationID FindNearestHangar(const Aircraft *v)
{
	const Station *st;
	uint best = 0;
	StationID index = INVALID_STATION;
	TileIndex vtile = TileVirtXY(v->x_pos, v->y_pos);
	const AircraftVehicleInfo *avi = AircraftVehInfo(v->engine_type);

	FOR_ALL_STATIONS(st) {
		if (st->owner != v->owner || !(st->facilities & FACIL_AIRPORT) || !st->airport.HasHangar()) continue;

		const AirportFTAClass *afc = st->airport.GetFTA();

		/* don't crash the plane if we know it can't land at the airport */
		if ((afc->flags & AirportFTAClass::SHORT_STRIP) && (avi->subtype & AIR_FAST) &&
				(!_cheats.no_jetcrash.value || !_settings_game.vehicle.large_plane_on_short_runway)) continue;

		/* the plane won't land at any helicopter station */
		if (!(afc->flags & AirportFTAClass::AIRPLANES) && (avi->subtype & AIR_CTOL)) continue;

		/* v->tile can't be used here, when aircraft is flying v->tile is set to 0 */
		uint distance = DistanceSquare(vtile, st->airport.tile);
		if (v->acache.cached_max_range_sqr != 0) {
			/* Determine destinations */
			const Station *cur_dest = GetTargetAirportIfValid(v);
			const Station *next_dest;
			if (v->current_order.IsType(OT_GOTO_STATION) ||
					v->current_order.IsType(OT_GOTO_DEPOT) && v->current_order.GetDepotActionType() != ODATFB_NEAREST_DEPOT) {
				next_dest = Station::GetIfValid(v->current_order.GetDestination());
				if (next_dest == cur_dest) next_dest = Station::GetIfValid(v->last_station_visited);
			} else {
				next_dest = Station::GetIfValid(v->GetNextStoppingStation().value);
			}

			/* Check if our current and next (or previous) destinations can be reached from the depot airport. */
			if (next_dest != NULL && next_dest->airport.tile != INVALID_TILE && cur_dest != NULL) {
				if (DistanceSquare(st->airport.tile, next_dest->airport.tile) > v->acache.cached_max_range_sqr ||
					DistanceSquare(st->airport.tile, cur_dest->airport.tile) > v->acache.cached_max_range_sqr) continue;
			} else if (next_dest != NULL && next_dest->airport.tile != INVALID_TILE && cur_dest == NULL) {
				if (DistanceSquare(st->airport.tile, next_dest->airport.tile) > v->acache.cached_max_range_sqr) continue;
			} else if ((next_dest == NULL || next_dest->airport.tile == INVALID_TILE) && cur_dest != NULL) {
				if (DistanceSquare(st->airport.tile, cur_dest->airport.tile) > v->acache.cached_max_range_sqr) continue;
			}
		}
		if (distance < best || index == INVALID_STATION) {
			best = distance;
			index = st->index;
		}
	}
	return index;
}