static const Depot *FindClosestShipDepot(const Vehicle *v, uint max_distance)
{
	/* Find the closest depot */
	const Depot *depot;
	const Depot *best_depot = NULL;
	/* If we don't have a maximum distance, i.e. distance = 0,
	 * we want to find any depot so the best distance of no
	 * depot must be more than any correct distance. On the
	 * other hand if we have set a maximum distance, any depot
	 * further away than max_distance can safely be ignored. */
	uint best_dist = max_distance == 0 ? UINT_MAX : max_distance + 1;

	FOR_ALL_DEPOTS(depot) {
		TileIndex tile = depot->xy;
		if (IsShipDepotTile(tile) && IsTileOwner(tile, v->owner)) {
			uint dist = DistanceManhattan(tile, v->tile);
			if (dist < best_dist) {
				best_dist = dist;
				best_depot = depot;
			}
		}
	}

	return best_depot;
}