Have a block change when a player sleeps

I remember an old 1.6.4 mod called ChristmasCraft, made by newthead and once updated to 1.7.10 by Zuxelas.  The stocking block included in the mod changes to have a present in it when the player sleeps, and the present could be retrieved by a right-click.

How can I transfer this code into a 1.12.2 version?

Here's the code used in the mod's 1.7.10 version:

@SubscribeEvent
	public void onWorldTick(WorldTickEvent event)
	{
		if (event.phase == Phase.START)
		{
			if (!ChristmasCraft.isChristmasTime())
			{
				return;
			}
			boolean isChristmasDay = ChristmasCraft.isChristmasDay();
			WorldServer world = (WorldServer)event.world;
			if (world.areAllPlayersAsleep())
			{
				Object[] tiles = world.loadedTileEntityList.toArray();
				for (int i = 0; i < tiles.length; i++)
				{
					TileEntity tile = (TileEntity)tiles[i];
					Block block = world.getBlock(tile.xCoord, tile.yCoord, tile.zCoord);
					if (block == ChristmasCraft.blockStocking)
					{
						ItemStack present = ChristmasCraft.getRandomStockingGift();
						if (((TileEntityStocking)tile).getContents() == null)
						{
							((TileEntityStocking)tile).setContents(present);
						}
					}
					if (isChristmasDay && block == ChristmasCraft.blockTreestand)
					{
						generatePresentsAroundTree(world, tile.xCoord, tile.yCoord, tile.zCoord);
					}
				}
			}
		}
	}

BlockStocking:

@Override
	public boolean onBlockActivated(World world, int i, int j, int k, EntityPlayer entityplayer, int side, float f1, float f2, float f3)
	{
		ItemStack contents = null;
		TileEntityStocking tile = (TileEntityStocking)world.getTileEntity(i, j, k);
		if (tile != null && tile.getContents() != null)
		{
			contents = tile.getContents();
		}
		if (entityplayer.getCurrentEquippedItem() != null && contents == null)
		{
			ItemStack heldItem = entityplayer.getCurrentEquippedItem();
			if (Block.getBlockFromItem(heldItem.getItem()) == ChristmasCraft.blockPresent)
			{
				ItemStack newContents = heldItem.copy();
				newContents.stackSize = 1;
				tile.setContents(newContents);
				heldItem.stackSize -= 1;
				return true;
			}
		}
		else
		{
			dropStockingContents(world, i, j, k);
			return true;
		}
		return false;
	}