WIP

src/main/java/eu/oskar3123/spigot2fa/Main.java

@@ -4,7 +4,8 @@ import eu.oskar3123.spigot2fa.command.TFACommand;
 import eu.oskar3123.spigot2fa.config.Config;
 import eu.oskar3123.spigot2fa.config.ConfigHandler;
 import eu.oskar3123.spigot2fa.handler.TFAHandler;
-import eu.oskar3123.spigot2fa.listener.JoinQuitListener;
+import eu.oskar3123.spigot2fa.listener.AuthListener;
+import eu.oskar3123.spigot2fa.listener.MapListener;
 import org.bukkit.plugin.PluginManager;
 import org.bukkit.plugin.java.JavaPlugin;
 
@@ -41,7 +42,8 @@ public class Main extends JavaPlugin
     private void registerListeners()
     {
         PluginManager pm = this.getServer().getPluginManager();
-        pm.registerEvents(new JoinQuitListener(this), this);
+        pm.registerEvents(new AuthListener(this), this);
+        pm.registerEvents(new MapListener(this), this);
     }
 
 }

src/main/java/eu/oskar3123/spigot2fa/command/TFACommand.java

@@ -2,18 +2,28 @@ package eu.oskar3123.spigot2fa.command;
 
 import eu.oskar3123.spigot2fa.Main;
 import eu.oskar3123.spigot2fa.handler.TFAHandler;
-import eu.oskar3123.spigot2fa.tfa.TFA;
+import eu.oskar3123.spigot2fa.util.PlayerUtils;
 import org.apache.commons.lang.StringUtils;
+import org.bukkit.OfflinePlayer;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandExecutor;
 import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
 import org.bukkit.entity.Player;
+import org.bukkit.util.StringUtil;
 
-public class TFACommand implements CommandExecutor
+import java.util.*;
+
+public class TFACommand implements CommandExecutor, TabCompleter
 {
 
     private Main plugin;
     private TFAHandler th;
+    private final Map<String, String[]> TAB_COMPLETE_MAP = new HashMap<>();
+    {
+        TAB_COMPLETE_MAP.put("", new String[]{"add", "remove", "<code>"});
+        TAB_COMPLETE_MAP.put(":remove", new String[]{"[player]"});
+    }
 
     public TFACommand(Main plugin)
     {
@@ -25,29 +35,123 @@ public class TFACommand implements CommandExecutor
     public boolean onCommand(CommandSender sender, Command command, String label, String[] args)
     {
         Player player = (Player) sender;
-        if (!th.isInProcess(player.getUniqueId()))
+        if (args.length >= 1 && args[0].equalsIgnoreCase("remove"))
         {
-            th.startCreating(player);
+            if (!player.hasPermission("2fa.remove"))
-            return true;
-        }
-        else
-        {
-            String secret = th.getKey(player.getUniqueId());
-            String code = TFA.getTOTPCode(secret);
-            String pCode = StringUtils.join(args);
-            if (th.matchCode(code, pCode))
             {
-                th.creatingSuccess(player);
+                player.sendMessage("You don't have permission to do that");
-                player.sendMessage("Successfully activated 2FA");
+                return true;
+            }
+            if (args.length >= 2 && player.hasPermission("2fa.remove.other"))
+            {
+                OfflinePlayer otherPlayer = PlayerUtils.getOfflinePlayer(args[1]);
+                if (otherPlayer == null)
+                {
+                    player.sendMessage("Could not find player \"" + args[1] + "\".");
+                    return true;
+                }
+                if (th.hasEnabled2FA(otherPlayer.getUniqueId()))
+                {
+                    th.remove2FA(otherPlayer.getUniqueId());
+                    player.sendMessage("Removed two-factor authentication for " + otherPlayer.getName() + ".");
+                    return true;
+                }
+                else
+                {
+                    player.sendMessage(otherPlayer.getName() + " does not have two-factor authentication enabled.");
+                    return true;
+                }
+            }
+            if (th.hasEnabled2FA(player.getUniqueId()))
+            {
+                th.remove2FA(player.getUniqueId());
+                player.sendMessage("Removed two-factor authentication.");
                 return true;
             }
             else
             {
-                th.creatingFailed(player);
+                player.sendMessage("You don't have two-factor authentication enabled.");
-                player.sendMessage("That code is incorrect, aborting");
+                return true;
+            }
+        }
+        else if (args.length >= 1 && args[0].equalsIgnoreCase("add"))
+        {
+            if (!player.hasPermission("2fa.activate"))
+            {
+                player.sendMessage("You don't have permission to do that");
+                return true;
+            }
+            if (th.hasEnabled2FA(player.getUniqueId()))
+            {
+                player.sendMessage("You have already enabled two-factor authentication.");
+                return true;
+            }
+            if (!th.isInProcess(player.getUniqueId()))
+            {
+                boolean canStart = th.startCreating(player);
+                if (!canStart)
+                {
+                    player.sendMessage("You can't hold anything when starting the process.");
+                    return true;
+                }
+                player.sendMessage("Scan the barcode or enter the secret manually in your 2FA app.");
+                player.sendMessage("Use /2fa <code> to verify the authenticator.");
+                return true;
+            }
+            else
+            {
+                String secret = th.getKey(player.getUniqueId());
+                String pCode = StringUtils.join(args);
+                if (th.matchCode(secret, pCode))
+                {
+                    th.creatingSuccess(player);
+                    player.sendMessage("Successfully activated two-factor authentication.");
+                    return true;
+                }
+                else
+                {
+                    th.creatingFailed(player);
+                    player.sendMessage("That code is incorrect, aborting.");
+                    return true;
+                }
+            }
+        }
+        else
+        {
+            if (th.isInProcess(player.getUniqueId()))
+            {
+                player.sendMessage("Confirm the activation by typing /2fa <code>.");
+                return true;
+            }
+            else
+            {
+                player.sendMessage("Usage: " + command.getUsage().replace("<command>", label));
                 return true;
             }
         }
     }
 
+    @Override
+    public List<String> onTabComplete(CommandSender sender, Command command, String alias, String[] args)
+    {
+        if (args.length < 1)
+        {
+            return new ArrayList<>();
+        }
+        StringBuilder search = new StringBuilder();
+        for (int i = 0; i < args.length - 1; i++)
+        {
+            search.append(":").append(args[i]);
+        }
+        if (!TAB_COMPLETE_MAP.containsKey(search.toString()))
+        {
+            return new ArrayList<>();
+        }
+        String[] commands = TAB_COMPLETE_MAP.get(search.toString());
+        final List<String> completions = new ArrayList<>();
+        StringUtil.copyPartialMatches(args[args.length - 1], Arrays.asList(commands), completions);
+        Collections.sort(completions);
+        return completions;
+    }
+
 }

src/main/java/eu/oskar3123/spigot2fa/config/ConfigHandler.java

@@ -1,6 +1,7 @@
 package eu.oskar3123.spigot2fa.config;
 
 import com.google.common.base.Charsets;
+import org.bukkit.Bukkit;
 import org.bukkit.configuration.file.FileConfiguration;
 import org.bukkit.configuration.file.YamlConfiguration;
 import org.bukkit.plugin.java.JavaPlugin;
@@ -55,18 +56,40 @@ public class ConfigHandler
     }
 
     public void saveConfig(Config config)
+    {
+        saveConfig(config, false);
+    }
+
+    public void saveConfig(Config config, boolean async)
     {
         if (config.fileConfig == null || config.file == null)
         {
             return;
         }
-        try
+        if (async)
         {
-            getConfig(config).save(config.file);
+            Bukkit.getScheduler().runTaskAsynchronously(plugin, () ->
+            {
+                try
+                {
+                    getConfig(config).save(config.file);
+                }
+                catch (IOException e)
+                {
+                    plugin.getLogger().log(Level.SEVERE, "Could not save config to " + config.file, e);
+                }
+            });
         }
-        catch (IOException ex)
+        else
         {
-            plugin.getLogger().log(Level.SEVERE, "Could not save config to " + config.file, ex);
+            try
+            {
+                getConfig(config).save(config.file);
+            }
+            catch (IOException e)
+            {
+                plugin.getLogger().log(Level.SEVERE, "Could not save config to " + config.file, e);
+            }
         }
     }
 
@@ -80,6 +103,7 @@ public class ConfigHandler
         {
             plugin.saveResource(config.name + ".yml", false);
         }
+        reloadConfig(config);
     }
 
 }

src/main/java/eu/oskar3123/spigot2fa/handler/TFAHandler.java

@@ -12,6 +12,7 @@ import org.bukkit.inventory.meta.MapMeta;
 import org.bukkit.map.MapView;
 
 import java.io.IOException;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.UUID;
@@ -27,21 +28,67 @@ public class TFAHandler
         this.plugin = plugin;
     }
 
+    public boolean shouldBypassCode(Player player)
+    {
+        UUID uuid = player.getUniqueId();
+        String ip = player.getAddress().getAddress().getHostAddress();
+        if (!hasEnabled2FA(uuid))
+        {
+            return true;
+        }
+        long now = new Date().getTime();
+        long sessionTimeInMs = plugin.configHandler.getConfig(plugin.config).getLong("2fa.sessiontime") * 60000L;
+        Configuration players = plugin.configHandler.getConfig(plugin.players);
+        long last = players.getLong(uuid.toString() + ".lastlogin");
+        String lastIp = players.getString(uuid.toString() + ".lastip");
+        return last >= now - sessionTimeInMs && ip.equalsIgnoreCase(lastIp);
+    }
+
+    public void setLastLogin(Player player, Long time)
+    {
+        UUID uuid = player.getUniqueId();
+        String ip = player.getAddress().getAddress().getHostAddress();
+        if (!hasEnabled2FA(uuid))
+        {
+            return;
+        }
+        long now;
+        if (time == null)
+        {
+            now = new Date().getTime();
+        }
+        else
+        {
+            now = time;
+        }
+        Configuration players = plugin.configHandler.getConfig(plugin.players);
+        players.set(uuid.toString() + ".lastlogin", now);
+        players.set(uuid.toString() + ".lastip", ip);
+        plugin.configHandler.saveConfig(plugin.players, true);
+    }
+
     public String formatSecret(String secret)
     {
         return secret.toLowerCase().replaceAll("(.{4})(?=.{4})", "$1 ");
     }
 
+    public void remove2FA(UUID uuid)
+    {
+        plugin.configHandler.getConfig(plugin.players).set(uuid.toString(), null);
+        plugin.configHandler.saveConfig(plugin.players, true);
+    }
+
     public boolean hasEnabled2FA(UUID uuid)
     {
-        return plugin.configHandler.getConfig(plugin.players).isString(uuid.toString());
+        return plugin.configHandler.getConfig(plugin.players).isString(uuid.toString() + ".secret");
     }
 
     public void creatingSuccess(Player player)
     {
         String secret = remove(player.getUniqueId());
-        plugin.configHandler.getConfig(plugin.players).set(player.getUniqueId().toString(), secret);
+        player.getInventory().setItemInMainHand(new ItemStack(Material.AIR));
-        plugin.configHandler.saveConfig(plugin.players);
+        plugin.configHandler.getConfig(plugin.players).set(player.getUniqueId().toString() + ".secret", secret);
+        plugin.configHandler.saveConfig(plugin.players, true);
     }
 
     public void creatingFailed(Player player)
@@ -49,15 +96,22 @@ public class TFAHandler
         remove(player.getUniqueId());
     }
 
-    public boolean matchCode(String code1, String code2)
+    public boolean matchCode(String secret, String code)
     {
-        return code1.equalsIgnoreCase(code2);
+        String[] actualCodes = TFA.getTOTPCodes(secret);
+        for (String actualCode : actualCodes)
+        {
+            if (actualCode.equalsIgnoreCase(code))
+            {
+                return true;
+            }
+        }
+        return false;
     }
 
     public boolean matchCode(Player player, String code)
     {
-        String actualCode = TFA.getTOTPCode(getKey(player.getUniqueId()));
+        return matchCode(getKey(player.getUniqueId()), code);
-        return matchCode(actualCode, code);
     }
 
     private String remove(UUID uuid)
@@ -65,33 +119,42 @@ public class TFAHandler
         return isInProcess.remove(uuid);
     }
 
-    public String startCreating(Player player)
+    public boolean startCreating(Player player)
     {
         String key = TFA.getRandomSecretKey();
-        isInProcess.put(player.getUniqueId(), key);
+        boolean couldShow = showQRCode(player, key);
-        showQRCode(player, key);
+        if (couldShow)
-        return key;
+        {
+            isInProcess.put(player.getUniqueId(), key);
+        }
+        return couldShow;
     }
 
-    private void showQRCode(Player player, String secret)
+    private boolean showQRCode(Player player, String secret)
     {
+        ItemStack inHand = player.getInventory().getItemInMainHand();
+        if (inHand != null && inHand.getType() != Material.AIR)
+        {
+            return false;
+        }
         try
         {
             ItemStack map = new ItemStack(Material.FILLED_MAP);
             MapView view = Bukkit.createMap(player.getWorld());
             view.getRenderers().clear();
-            view.addRenderer(new QRMapRenderer(secret, player));
+            view.addRenderer(new QRMapRenderer(plugin, formatSecret(secret), player));
             MapMeta mapMeta = (MapMeta) map.getItemMeta();
             mapMeta.setMapId(view.getId());
             map.setItemMeta(mapMeta);
             player.getInventory().setItemInMainHand(map);
             player.sendMap(view);
-            player.sendMessage("Secret Key: " + secret);
+            return true;
         }
         catch (IOException e)
         {
             e.printStackTrace();
             player.sendMessage("Failed to generate qr code");
+            return false;
         }
     }
 
@@ -107,7 +170,16 @@ public class TFAHandler
             return isInProcess.get(uuid);
         }
         Configuration players = plugin.configHandler.getConfig(plugin.players);
-        return players.getString(uuid.toString());
+        return players.getString(uuid.toString() + ".secret");
+    }
+
+    public void stopCreating(Player player)
+    {
+        if (!isInProcess(player.getUniqueId()))
+        {
+            return;
+        }
+        isInProcess.remove(player.getUniqueId());
     }
 
 }

src/main/java/eu/oskar3123/spigot2fa/listener/AuthListener.java

@@ -0,0 +1,105 @@
+package eu.oskar3123.spigot2fa.listener;
+
+import eu.oskar3123.spigot2fa.Main;
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.AsyncPlayerChatEvent;
+import org.bukkit.event.player.PlayerCommandPreprocessEvent;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.potion.PotionEffect;
+import org.bukkit.potion.PotionEffectType;
+import org.bukkit.scheduler.BukkitTask;
+
+import java.util.*;
+
+public class AuthListener implements Listener
+{
+
+    private class WaitingInfo
+    {
+        private BukkitTask kickTask;
+        private BukkitTask teleportTask;
+
+        private WaitingInfo(BukkitTask kickTask, BukkitTask teleportTask)
+        {
+            this.kickTask = kickTask;
+            this.teleportTask = teleportTask;
+        }
+
+        private void cancel(Player player)
+        {
+            this.kickTask.cancel();
+            this.teleportTask.cancel();
+            player.removePotionEffect(PotionEffectType.BLINDNESS);
+        }
+    }
+
+    private Main plugin;
+    private Map<UUID, WaitingInfo> waitingForCode = new HashMap<>();
+
+    public AuthListener(Main plugin)
+    {
+        this.plugin = plugin;
+    }
+
+    @EventHandler
+    public void onJoin(PlayerJoinEvent event)
+    {
+        if (plugin.tfaHandler.shouldBypassCode(event.getPlayer()))
+        {
+            event.getPlayer().sendMessage("bypassed 2fa check");
+            return;
+        }
+        final Player player = event.getPlayer();
+        BukkitTask task = Bukkit.getScheduler().runTaskLater(plugin, () ->
+        {
+            waitingForCode.remove(player.getUniqueId());
+            player.kickPlayer("You did not enter the 2FA code in time.");
+        }, 800L);
+        // 800 ticks == 40 secs
+        final Location loginLocation = player.getLocation().clone();
+        BukkitTask tpTask = Bukkit.getScheduler().runTaskTimer(plugin, () ->
+        {
+            player.teleport(loginLocation);
+            player.addPotionEffect(new PotionEffect(PotionEffectType.BLINDNESS, 45, 0, false, false), true);
+        }, 0L, 20L);
+        waitingForCode.put(player.getUniqueId(), new WaitingInfo(task, tpTask));
+        Bukkit.getScheduler().runTaskLater(plugin, () -> player.sendMessage("Please enter your 2FA code in the chat."), 1L);
+    }
+
+    @EventHandler
+    public void chat(AsyncPlayerChatEvent event)
+    {
+        if (!waitingForCode.containsKey(event.getPlayer().getUniqueId()))
+        {
+            return;
+        }
+        boolean correct = plugin.tfaHandler.matchCode(event.getPlayer(), event.getMessage());
+        event.setCancelled(true);
+        if (!correct)
+        {
+            event.getPlayer().sendMessage("Incorrect code, try again.");
+        }
+        else
+        {
+            waitingForCode.remove(event.getPlayer().getUniqueId()).cancel(event.getPlayer());
+            plugin.tfaHandler.setLastLogin(event.getPlayer(), null);
+            event.getPlayer().sendMessage("You have been authorized.");
+        }
+    }
+
+    @EventHandler
+    public void command(PlayerCommandPreprocessEvent event)
+    {
+        if (!waitingForCode.containsKey(event.getPlayer().getUniqueId()))
+        {
+            return;
+        }
+        event.setCancelled(true);
+        event.getPlayer().sendMessage("You have to authorize first.");
+    }
+
+}

src/main/java/eu/oskar3123/spigot2fa/listener/JoinQuitListener.java

@@ -1,59 +0,0 @@
-package eu.oskar3123.spigot2fa.listener;
-
-import eu.oskar3123.spigot2fa.Main;
-import org.bukkit.Bukkit;
-import org.bukkit.entity.Player;
-import org.bukkit.event.EventHandler;
-import org.bukkit.event.Listener;
-import org.bukkit.event.player.AsyncPlayerChatEvent;
-import org.bukkit.event.player.PlayerJoinEvent;
-
-import java.util.HashSet;
-import java.util.Set;
-import java.util.UUID;
-
-public class JoinQuitListener implements Listener
-{
-
-    private Main plugin;
-    private Set<UUID> waitingForCode = new HashSet<>();
-
-    public JoinQuitListener(Main plugin)
-    {
-        this.plugin = plugin;
-    }
-
-    @EventHandler
-    public void onJoin(PlayerJoinEvent event)
-    {
-        boolean enabled = plugin.tfaHandler.hasEnabled2FA(event.getPlayer().getUniqueId());
-        if (!enabled)
-        {
-            return;
-        }
-        event.getPlayer().sendMessage("Enter 2FA code");
-        waitingForCode.add(event.getPlayer().getUniqueId());
-    }
-
-    @EventHandler
-    public void chat(AsyncPlayerChatEvent event)
-    {
-        if (!waitingForCode.contains(event.getPlayer().getUniqueId()))
-        {
-            return;
-        }
-        boolean correct = plugin.tfaHandler.matchCode(event.getPlayer(), event.getMessage());
-        waitingForCode.remove(event.getPlayer().getUniqueId());
-        event.setCancelled(true);
-        if (!correct)
-        {
-            final Player player = event.getPlayer();
-            Bukkit.getScheduler().runTask(plugin, () -> player.kickPlayer("Wrong code!"));
-        }
-        else
-        {
-            event.getPlayer().sendMessage("Logged in");
-        }
-    }
-
-}

src/main/java/eu/oskar3123/spigot2fa/listener/MapListener.java

@@ -0,0 +1,100 @@
+package eu.oskar3123.spigot2fa.listener;
+
+import eu.oskar3123.spigot2fa.Main;
+import org.bukkit.Material;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.inventory.*;
+import org.bukkit.event.player.PlayerDropItemEvent;
+import org.bukkit.event.player.PlayerItemHeldEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+import org.bukkit.inventory.ItemStack;
+
+public class MapListener implements Listener
+{
+
+    private Main plugin;
+
+    public MapListener(Main plugin)
+    {
+        this.plugin = plugin;
+    }
+
+    @EventHandler
+    public void quit(PlayerQuitEvent event)
+    {
+        if (!plugin.tfaHandler.isInProcess(event.getPlayer().getUniqueId()))
+        {
+            return;
+        }
+        plugin.tfaHandler.stopCreating(event.getPlayer());
+        event.getPlayer().getInventory().setItemInMainHand(new ItemStack(Material.AIR));
+    }
+
+    @EventHandler
+    public void drop(PlayerDropItemEvent event)
+    {
+        if (!plugin.tfaHandler.isInProcess(event.getPlayer().getUniqueId()))
+        {
+            return;
+        }
+        if (event.getItemDrop().getItemStack().getType() != Material.FILLED_MAP)
+        {
+            return;
+        }
+        plugin.tfaHandler.stopCreating(event.getPlayer());
+        event.getPlayer().sendMessage("Aborted adding two-factor authentication.");
+        event.getItemDrop().remove();
+    }
+
+    @EventHandler
+    public void slot(PlayerItemHeldEvent event)
+    {
+        if (!plugin.tfaHandler.isInProcess(event.getPlayer().getUniqueId()))
+        {
+            return;
+        }
+        event.setCancelled(true);
+    }
+
+    @EventHandler
+    public void open(InventoryOpenEvent event)
+    {
+        if (!plugin.tfaHandler.isInProcess(event.getPlayer().getUniqueId()))
+        {
+            return;
+        }
+        event.setCancelled(true);
+    }
+
+    @EventHandler
+    public void open(InventoryClickEvent event)
+    {
+        if (!plugin.tfaHandler.isInProcess(event.getWhoClicked().getUniqueId()))
+        {
+            return;
+        }
+        event.setCancelled(true);
+    }
+
+    @EventHandler
+    public void open(InventoryCreativeEvent event)
+    {
+        if (!plugin.tfaHandler.isInProcess(event.getWhoClicked().getUniqueId()))
+        {
+            return;
+        }
+        event.setCancelled(true);
+    }
+
+    @EventHandler
+    public void open(InventoryDragEvent event)
+    {
+        if (!plugin.tfaHandler.isInProcess(event.getWhoClicked().getUniqueId()))
+        {
+            return;
+        }
+        event.setCancelled(true);
+    }
+
+}

src/main/java/eu/oskar3123/spigot2fa/map/CreateMapRunnable.java

@@ -1,47 +0,0 @@
-package eu.oskar3123.spigot2fa.map;
-
-import eu.oskar3123.spigot2fa.tfa.TFA;
-import org.bukkit.Bukkit;
-import org.bukkit.Material;
-import org.bukkit.entity.Player;
-import org.bukkit.inventory.ItemStack;
-import org.bukkit.inventory.meta.MapMeta;
-import org.bukkit.map.MapView;
-
-import java.io.IOException;
-
-public class CreateMapRunnable implements Runnable
-{
-
-    private Player player;
-
-    public CreateMapRunnable(Player player)
-    {
-        this.player = player;
-    }
-
-    @Override
-    public void run()
-    {
-        try
-        {
-            ItemStack map = new ItemStack(Material.FILLED_MAP);
-            MapView view = Bukkit.createMap(player.getWorld());
-            view.getRenderers().clear();
-            String secret = TFA.getRandomSecretKey();
-            view.addRenderer(new QRMapRenderer(secret, player));
-            MapMeta mapMeta = (MapMeta) map.getItemMeta();
-            mapMeta.setMapId(view.getId());
-            map.setItemMeta(mapMeta);
-            player.getInventory().setItemInMainHand(map);
-            player.sendMap(view);
-            player.sendMessage("Secret Key: " + secret);
-        }
-        catch (IOException e)
-        {
-            e.printStackTrace();
-            player.sendMessage("Failed to generate qr code");
-        }
-    }
-
-}

src/main/java/eu/oskar3123/spigot2fa/map/QRMapRenderer.java

@@ -25,10 +25,14 @@ public class QRMapRenderer extends MapRenderer
     {
         this.plugin = plugin;
         this.uuid = player.getUniqueId();
-        String[] formattedSecretKey = secretKey .replaceAll("((?:.{4} ){4})", "$1;").split(";");
+        String[] formattedSecretKey = secretKey.replaceAll("((?:.{4} ){4})", "$1;").split(";");
         this.line1 = formattedSecretKey[0].trim();
         this.line2 = formattedSecretKey[1].trim();
-        initImage(TFA.getGoogleAuthenticatorBarCode(secretKey, "Mineworlds", player.getName() + " (" + player.getUniqueId().toString() + ")"));
+        String issuer = plugin.configHandler.getConfig(plugin.config).getString("2fa.issuer");
+        String account = plugin.configHandler.getConfig(plugin.config).getString("2fa.account")
+                .replace("{NAME}", player.getName())
+                .replace("{UUID}", player.getUniqueId().toString());
+        initImage(TFA.getGoogleAuthenticatorBarCode(secretKey, issuer, account));
     }
 
     private void initImage(String qrValue) throws IOException

src/main/java/eu/oskar3123/spigot2fa/tfa/TFA.java

@@ -22,7 +22,7 @@ public class TFA
         return secretKey.toUpperCase();
     }
 
-    public static String getTOTPCode(String secretKey)
+    public static String[] getTOTPCodes(String secretKey)
     {
         String normalizedBase32Key = secretKey.replace(" ", "").toUpperCase();
         Base32 base32 = new Base32();
@@ -30,7 +30,11 @@ public class TFA
         String hexKey = Hex.encodeHexString(bytes);
         long time = (System.currentTimeMillis() / 1000) / 30;
         String hexTime = Long.toHexString(time);
-        return TOTP.generateTOTP(hexKey, hexTime, "6");
+        String code1 = TOTP.generateTOTP(hexKey, hexTime, "6");
+        time = time - 1;
+        hexTime = Long.toHexString(time);
+        String code2 = TOTP.generateTOTP(hexKey, hexTime, "6");
+        return new String[] {code1, code2};
     }
 
     public static String getGoogleAuthenticatorBarCode(String secretKey, String issuer, String account)

src/main/java/eu/oskar3123/spigot2fa/util/PlayerUtils.java

@@ -0,0 +1,25 @@
+package eu.oskar3123.spigot2fa.util;
+
+import org.bukkit.Bukkit;
+import org.bukkit.OfflinePlayer;
+
+public class PlayerUtils
+{
+
+    public static OfflinePlayer getOfflinePlayer(String name)
+    {
+        for (OfflinePlayer ply : Bukkit.getOfflinePlayers())
+        {
+            if (ply == null || ply.getName() == null || ply.getName().isEmpty())
+            {
+                continue;
+            }
+            if (ply.getName().toLowerCase().startsWith(name.toLowerCase()))
+            {
+                return ply;
+            }
+        }
+        return null;
+    }
+
+}

src/main/resources/config.yml

@@ -1,3 +1,5 @@
 2fa:
   issuer: 'Mineworlds'
   account: '{NAME}'
+  # session time in minutes
+  sessiontime: 1440

src/main/resources/plugin.yml

@@ -5,3 +5,5 @@ authors: [oskar3123]
 main: eu.oskar3123.spigot2fa.Main
 commands:
   2fa:
+    usage: '/<command> add/remove/<code>'
+    description: 'Two-factor authorization command'