Main

import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.BlockBreakEvent;
import org.bukkit.event.block.BlockPlaceEvent;
import org.bukkit.event.entity.EntityDamageEvent;
import org.bukkit.event.entity.FoodLevelChangeEvent;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.event.player.PlayerDropItemEvent;
import org.bukkit.plugin.java.JavaPlugin;

import java.util.ArrayList;

public class Main extends JavaPlugin implements CommandExecutor, Listener {

    public ArrayList<String> build = new ArrayList<>();

    @Override
    public void onEnable() {
        getServer().getPluginCommand("Build").setExecutor(this);
        getServer().getPluginManager().registerEvents(this, this);
    }

    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        if (sender instanceof Player) {
            if (sender.hasPermission("build")) {
                Player player = (Player) sender;
                if (build.contains(player.toString())) {
                    build.remove(player.toString());
                    player.sendMessage("BuildMode: off");
                } else {
                    build.add(player.toString());
                    player.sendMessage("BuildMode: on");
                }
            }
        }
        return false;
    }

    @EventHandler
    public void on(BlockPlaceEvent e) {
        Player player = e.getPlayer();
        if (!build.contains(player.toString())) {
            e.setCancelled(true);
        }
    }

    @EventHandler
    public void on(BlockBreakEvent e) {
        Player player = e.getPlayer();
        if (!build.contains(player.toString())) {
            e.setCancelled(true);
        }
    }

    @EventHandler
    public void on(InventoryClickEvent e) {
        Player player = (Player) e.getWhoClicked();
        if (!build.contains(player.toString())) {
            e.setCancelled(true);
        }
    }

    @EventHandler
    public void on(PlayerDropItemEvent e) {
        Player player = e.getPlayer();
        if (!build.contains(player.toString())) {
            e.setCancelled(true);
        }
    }

    @EventHandler
    public void on(FoodLevelChangeEvent e) {
        Player player = (Player) e.getEntity();
        if (!build.contains(player.toString())) {
            e.setCancelled(true);
        }
    }

    @EventHandler
    public void on(EntityDamageEvent e) {
        if (e.getEntity() instanceof Player) {
            Player player = (Player) e.getEntity();
            if (!build.contains(player.toString())) {
                e.setCancelled(true);
            }
        } else {
            e.setCancelled(true);
        }
    }

}