@Override
	public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args){
		if(cmd.getName().equalsIgnoreCase("essentialssings")){
			if(args.length == 3) {
				Player p = (Player) sender;
				if(p.getItemInHand() == null || p.getItemInHand().getType() == Material.AIR) {
					sender.sendMessage(ChatColor.RED + "Item in your hand is null or air");
					return true;
				}
				else if(!isInteger(args[1])) {
					sender.sendMessage(ChatColor.RED + "'" + args[1] + "' is not an integer!");
					return true;
				}
				else if(!isInteger(args[2])) {
					sender.sendMessage(ChatColor.RED + "'" + args[2] + "' is not an integer!");
					return true;
				}
				if(p.getTargetBlock(null, 5).getType() != Material.WALL_SIGN)  {
					sender.sendMessage(ChatColor.RED + "Your cursor is not targeted at the sign");
					return false;
				}
				Block b = p.getTargetBlock(null, 5);
				BlockState state = b.getState();
				Sign s = (Sign)state;
				String one = args[1];
				String two;
				ItemStack i = p.getItemInHand();
				if(i.getType() == Material.POTION || i.getType() == Material.SPLASH_POTION || i.getType() == Material.LINGERING_POTION) {
					two = i.getTypeId() + ":" + ;              // to za plusem to musi byc ta głupia data
				} else two = i.getTypeId() + ":" + i.getData().getData();
				String three = "$" + args[2];
				if(args[0].equalsIgnoreCase("buy")) {
					String zero = "[Buy]";
					s.setLine(0, zero);
			        s.setLine(1, one);
			        s.setLine(2, two);
			        s.setLine(3, three);
			        s.update();
			        String[] ss = new String [] {zero , one , two , three};
			        Bukkit.getServer().getPluginManager().callEvent(new SignChangeEvent(b, p, ss));
				}
				else if(args[0].equalsIgnoreCase("sell")) {
					String zero = "[Sell]";
					s.setLine(0, zero);
			        s.setLine(1, one);
			        s.setLine(2, two);
			        s.setLine(3, three);
			        s.update();
					String[] ss = new String [] {zero , one , two , three};
					Bukkit.getServer().getPluginManager().callEvent(new SignChangeEvent(b, p, ss));
				} else sender.sendMessage(ChatColor.RED + "'" + args[0] + "' must be 'buy' or 'sell'");
			} else sender.sendMessage(ChatColor.RED + "/essentialssings buy/sell amount cost");
		}
		return false;
	}
	public static boolean isInteger(String s) {
		try{
			Integer.parseInt(s);
			return true;
		} catch (NumberFormatException e) {
			return false;
		}
	}