/**
 * Is this tile a target for ships to get to a nearby dock?
 * @param tile Tile to query
 * @param diagdir Optional diagonal direction to look for axis compatibility.
 * @return True if the tile is a target for ships to get to a nearby dock.
 * @note If the axis of the provided diagdir is paralel to the axis of a nearby
 *       dock station, this function returns True. If diagdir is not provided,
 *       only tile locations are compared.
 */
static inline bool IsTileDock(TileIndex tile, DiagDirection diagdir = INVALID_DIAGDIR)
{
	Axis axis = diagdir == INVALID_DIAGDIR ? INVALID_AXIS : DiagDirToAxis(diagdir);

	for (DiagDirection rot = DIAGDIR_BEGIN; rot < DIAGDIR_END; rot++) {
		TileIndex tc = TileAddByDiagDir(tile, rot);
		if (IsTileType(tc, MP_STATION) && (IsDock(tc) || IsOilRig(tc))) {
			Station *dock = Station::GetByTile(tc);
			TileIndex docking_location = TILE_ADD(dock->dock_tile, ToTileIndexDiff(GetDockOffset(dock->dock_tile)));
			if (axis == INVALID_AXIS) {
				return tile == docking_location;
			}
			else {
				if (tile == docking_location) {
					Axis axis_tc = DiagDirToAxis(rot);
					return axis != axis_tc;
				}
			}
		}
		if (rot == DIAGDIR_NE && IsTileType(tc + TileDiffXY(-1, 0), MP_INDUSTRY) && GetIndustryGfx(tc + TileDiffXY(-1, 0)) == GFX_OILRIG_1) return true;
	}

	return false;
}