GuiCommand

package me.paris.test.commands;

import me.paris.test.Main;
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Material;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Item;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.event.inventory.InventoryType;
import org.bukkit.event.player.PlayerDropItemEvent;
import org.bukkit.inventory.Inventory;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.meta.ItemMeta;

public class GuiCommand implements CommandExecutor {

    private final Main main;
    private Inventory gui;

    public GuiCommand(Main main){

        this.main = main;

    }


    public void openNewGui(Player p){
        gui = Bukkit.createInventory(null, InventoryType.HOPPER); // Type of gui inventory
        ItemStack item0 = new ItemStack(Material.DIAMOND_BLOCK, 1);

        ItemMeta meta0 = item0.getItemMeta();
        meta0.setDisplayName(ChatColor.BLUE + "This is a button");

        item0.setItemMeta(meta0);

        gui.setItem(0, item0);

        p.openInventory(gui);
    }

    @EventHandler
    public void guiClickEvent(InventoryClickEvent e){
        if (!e.getInventory().equals(gui)){
            return;
        }

        e.setCancelled(true);

        Player p = (Player) e.getWhoClicked();

        switch(e.getSlot()) {
            case 0: {
                p.closeInventory();
                p.sendMessage(ChatColor.LIGHT_PURPLE + "This Works Now");
                break;
            }
        }

    }

    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {

        if (sender instanceof Player) {
            Player player = (Player) sender;
            if (player.isOp()) {

                openNewGui(player); //(Should) Open GUI


                return true;

            }
        }

        return true;
    }


}