code of EndiumEconomy

package ua.end433.endiumeconomy;

import me.clip.placeholderapi.expansion.PlaceholderExpansion;
import me.clip.placeholderapi.PlaceholderAPI;
import org.bukkit.Bukkit;
import org.bukkit.OfflinePlayer;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.configuration.file.FileConfiguration;
import org.bukkit.configuration.file.YamlConfiguration;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.ChatColor;
import org.jetbrains.annotations.NotNull;

import java.io.File;
import java.io.IOException;

public class EndiumEconomy extends JavaPlugin {

    private File vaultsFolder;

    @Override
    public void onEnable() {
        saveDefaultConfig();

        getLogger().info(getMessage("plugin-enabled"));

        // Register PlaceholderAPI expansion
        if (Bukkit.getPluginManager().getPlugin("PlaceholderAPI") != null) {
            new CurrencyExpansion(getDataFolder()).register();
            getLogger().info(getMessage("placeholderapi-registered"));
        } else {
            getLogger().warning(getMessage("placeholderapi-not-found"));
        }

        // Creating vaults folder
        vaultsFolder = new File(getDataFolder(), "vaults");
        if (!vaultsFolder.exists()) {
            if (vaultsFolder.mkdirs()) {
                getLogger().info(getMessage("vaults-folder-created"));
            } else {
                getLogger().warning(getMessage("vaults-folder-creation-failed"));
            }
        }
    }

    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        if (command.getName().equalsIgnoreCase("eec")) {
            if (args.length < 1) {
                sender.sendMessage(getMessage("not-enough-arguments"));
                return true;
            }

            String subCommand = args[0].toLowerCase();

            if (subCommand.equals("create")) {
                return handleCreate(sender, args);
            } else if (subCommand.equals("addm")) {
                return handleAddMoney(sender, args);
            } else if (subCommand.equals("removem")) {
                return handleRemoveMoney(sender, args);
            } else if (subCommand.equals("reload")) {
                return handleReload(sender);
            } else if (subCommand.equals("remove")) {
                return handleRemoveVault(sender, args);
            } else {
                sender.sendMessage(getMessage("unknown-command"));
                return true;
            }
        }
        return false;
    }

    private String getMessage(String key) {
        return ChatColor.translateAlternateColorCodes('&', getConfig().getString("messages." + key, "Missing message: " + key));
    }

    private boolean handleCreate(CommandSender sender, String[] args) {
        if (args.length < 2) {
            sender.sendMessage(getMessage("not-enough-arguments"));
            return true;
        }

        String vaultName = args[1];
        File vaultFile = new File(vaultsFolder, vaultName + ".yml");

        if (vaultFile.exists()) {
            sender.sendMessage(getMessage("vault-exists").replace("{vault}", vaultName));
            return true;
        }

        try {
            if (vaultFile.createNewFile()) {
                sender.sendMessage(getMessage("vault-created").replace("{vault}", vaultName));
            } else {
                sender.sendMessage(getMessage("vault-create-failed").replace("{vault}", vaultName));
            }
        } catch (IOException e) {
            sender.sendMessage(getMessage("error").replace("{error}", e.getMessage()));
            e.printStackTrace();
        }

        return true;
    }

    private boolean handleAddMoney(CommandSender sender, String[] args) {
        if (args.length < 4) {
            sender.sendMessage(getMessage("not-enough-arguments"));
            return true;
        }

        String vaultName = args[1];
        String playerName = args[2];
        int amount;

        try {
            amount = Integer.parseInt(args[3]);
        } catch (NumberFormatException e) {
            sender.sendMessage(getMessage("invalid-amount"));
            return true;
        }

        File vaultFile = new File(vaultsFolder, vaultName + ".yml");
        if (!vaultFile.exists()) {
            sender.sendMessage(getMessage("vault-not-found").replace("{vault}", vaultName));
            return true;
        }

        FileConfiguration vaultConfig = YamlConfiguration.loadConfiguration(vaultFile);
        int currentBalance = vaultConfig.getInt(playerName, 0);
        vaultConfig.set(playerName, currentBalance + amount);

        try {
            vaultConfig.save(vaultFile);
            sender.sendMessage(getMessage("player-balance-updated")
                    .replace("{player}", playerName)
                    .replace("{vault}", vaultName));
        } catch (IOException e) {
            sender.sendMessage(getMessage("error").replace("{error}", e.getMessage()));
            e.printStackTrace();
        }

        return true;
    }

    private boolean handleRemoveMoney(CommandSender sender, String[] args) {
        if (args.length < 4) {
            sender.sendMessage(getMessage("not-enough-arguments"));
            return true;
        }

        String vaultName = args[1];
        String playerName = args[2];
        int amount;

        try {
            amount = Integer.parseInt(args[3]);
        } catch (NumberFormatException e) {
            sender.sendMessage(getMessage("invalid-amount"));
            return true;
        }

        File vaultFile = new File(vaultsFolder, vaultName + ".yml");
        if (!vaultFile.exists()) {
            sender.sendMessage(getMessage("vault-not-found").replace("{vault}", vaultName));
            return true;
        }

        FileConfiguration vaultConfig = YamlConfiguration.loadConfiguration(vaultFile);
        int currentBalance = vaultConfig.getInt(playerName, 0);

        if (currentBalance < amount) {
            sender.sendMessage(getMessage("player-insufficient-balance")
                    .replace("{player}", playerName)
                    .replace("{vault}", vaultName));
            return true;
        }

        vaultConfig.set(playerName, currentBalance - amount);

        try {
            vaultConfig.save(vaultFile);
            sender.sendMessage(getMessage("player-balance-updated")
                    .replace("{player}", playerName)
                    .replace("{vault}", vaultName));
        } catch (IOException e) {
            sender.sendMessage(getMessage("error").replace("{error}", e.getMessage()));
            e.printStackTrace();
        }

        return true;
    }

    private boolean handleReload(CommandSender sender) {
        reloadConfig();
        sender.sendMessage(getMessage("plugin-reloaded"));
        return true;
    }

    private boolean handleRemoveVault(CommandSender sender, String[] args) {
        if (args.length < 2) {
            sender.sendMessage(getMessage("not-enough-arguments"));
            return true;
        }

        String vaultName = args[1];
        File vaultFile = new File(vaultsFolder, vaultName + ".yml");

        if (!vaultFile.exists()) {
            sender.sendMessage(getMessage("vault-not-found").replace("{vault}", vaultName));
            return true;
        }

        if (vaultFile.delete()) {
            sender.sendMessage(getMessage("vault-removed").replace("{vault}", vaultName));
        } else {
            sender.sendMessage(getMessage("vault-remove-failed").replace("{vault}", vaultName));
        }

        return true;
    }

    @Override
    public void onDisable() {
        getLogger().info(getMessage("plugin-disabled"));
    }
}

class CurrencyExpansion extends PlaceholderExpansion {

    private final File pluginFolder;

    public CurrencyExpansion(File pluginFolder) {
        this.pluginFolder = pluginFolder;
    }

    @Override
    public @NotNull String getIdentifier() {
        return "eec";
    }

    @Override
    public @NotNull String getAuthor() {
        return "end433";
    }

    @Override
    public @NotNull String getVersion() {
        return "1.00";
    }

    @Override
    public boolean persist() {
        return true;
    }

    @Override
    public boolean canRegister() {
        return true;
    }

    @Override
    public String onRequest(OfflinePlayer player, @NotNull String params) {
        String[] args = params.split("_");
        if (args.length != 1) {
            return null; // Invalid placeholder format
        }

        String vaultName = args[0];
        File vaultFile = new File(pluginFolder, "vaults/" + vaultName + ".yml");
        if (!vaultFile.exists()) {
            return "0"; // Vault not found
        }

        FileConfiguration vaultConfig = YamlConfiguration.loadConfiguration(vaultFile);
        String playerName = player.getName();
        if (playerName == null) {
            return "0"; // Player not found
        }

        int balance = vaultConfig.getInt(playerName, 0);
        return String.valueOf(balance);
    }
}