QoL/src/main/java/xyz/etztech/qol/commands/ListCommand.java

package xyz.etztech.qol.commands;

import org.apache.commons.lang.StringUtils;
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import xyz.etztech.qol.QoL;

import java.util.*;

public class ListCommand implements CommandExecutor {

    QoL plugin;

    public ListCommand(QoL plugin) {
        this.plugin = plugin;
    }

    @Override
    public boolean onCommand(CommandSender commandSender, Command command, String s, String[] strings) {

        Map<String, List<String>> list = new HashMap<>();
        List<String> groups = plugin.getConfig().getStringList("list");

        for (Player player : Bukkit.getServer().getOnlinePlayers()) {
            for (String group : groups) {
                if (player.hasPermission("qol.list." + group)) {
                    List<String> names = list.containsKey(group) ? list.get(group) : new ArrayList<String>();
                    names.add(player.getName());
                    list.put(group, names);
                    break;
                }
            }
        }
        StringBuilder message = new StringBuilder();
        for (String key : list.keySet()) {

            List<String> parts = Arrays.asList(key.split("_"));
            for (int i = 0; i < parts.size(); i++) {
                parts.set(i, StringUtils.capitalize(parts.get(i)));
            }
            message.append(ChatColor.GOLD)
                    .append(StringUtils.join(parts, " "))
                    .append(": ")
                    .append(ChatColor.YELLOW)
                    .append(StringUtils.join(list.get(key), ", "))
                    .append("\n");
        }

        commandSender.sendMessage(message.toString());

        return true;
    }
}