Implemented the unregister command

src/main/java/fr/xephi/authme/command/CommandManager.java

@@ -138,6 +138,21 @@ public class CommandManager {
         registerCommand.addArgument(new CommandArgumentDescription("player", "Player name", false));
         registerCommand.addArgument(new CommandArgumentDescription("password", "Password", false));
 
+        // Register the unregister command
+        CommandDescription unregisterCommand = new CommandDescription(
+                new UnregisterCommand(),
+                new ArrayList<String>() {{
+                    add("unregister");
+                    add("unreg");
+                    add("delete");
+                    add("del");
+                }},
+                "Unregister a player",
+                "Unregister the specified player.",
+                authMeCommand);
+        unregisterCommand.setCommandPermissions("authme.admin.unregister", CommandPermissions.DefaultPermission.OP_ONLY);
+        unregisterCommand.addArgument(new CommandArgumentDescription("player", "Player name", false));
+
         // Register the changepassword command
         CommandDescription changePasswordCommand = new CommandDescription(
                 new RegisterCommand(),

src/main/java/fr/xephi/authme/command/executable/authme/UnregisterCommand.java

@@ -0,0 +1,98 @@
+package fr.xephi.authme.command.executable.authme;
+
+import fr.xephi.authme.AuthMe;
+import fr.xephi.authme.ConsoleLogger;
+import fr.xephi.authme.Utils;
+import fr.xephi.authme.cache.auth.PlayerCache;
+import fr.xephi.authme.cache.limbo.LimboCache;
+import fr.xephi.authme.command.CommandParts;
+import fr.xephi.authme.command.ExecutableCommand;
+import fr.xephi.authme.events.SpawnTeleportEvent;
+import fr.xephi.authme.settings.Messages;
+import fr.xephi.authme.settings.Settings;
+import fr.xephi.authme.task.MessageTask;
+import fr.xephi.authme.task.TimeoutTask;
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.bukkit.potion.PotionEffect;
+import org.bukkit.potion.PotionEffectType;
+import org.bukkit.scheduler.BukkitScheduler;
+import org.bukkit.scheduler.BukkitTask;
+
+public class UnregisterCommand extends ExecutableCommand {
+
+    /**
+     * Execute the command.
+     *
+     * @param sender           The command sender.
+     * @param commandReference The command reference.
+     * @param commandArguments The command arguments.
+     *
+     * @return True if the command was executed successfully, false otherwise.
+     */
+    @Override
+    public boolean executeCommand(final CommandSender sender, CommandParts commandReference, CommandParts commandArguments) {
+        // AuthMe plugin instance
+        final AuthMe plugin = AuthMe.getInstance();
+
+        // Messages instance
+        final Messages m = Messages.getInstance();
+
+        // Get the player name
+        String playerName = commandArguments.get(0);
+        String playerNameLowerCase = playerName.toLowerCase();
+
+        // Make sure the user is valid
+        if (!plugin.database.isAuthAvailable(playerNameLowerCase)) {
+            m.send(sender, "user_unknown");
+            return true;
+        }
+
+        // Remove the player
+        if (!plugin.database.removeAuth(playerNameLowerCase)) {
+            m.send(sender, "error");
+            return true;
+        }
+
+        // Unregister the player
+        @SuppressWarnings("deprecation")
+        Player target = Bukkit.getPlayer(playerNameLowerCase);
+        PlayerCache.getInstance().removePlayer(playerNameLowerCase);
+        Utils.setGroup(target, Utils.GroupType.UNREGISTERED);
+        if (target != null) {
+            if (target.isOnline()) {
+                if (Settings.isTeleportToSpawnEnabled && !Settings.noTeleport) {
+                    Location spawn = plugin.getSpawnLocation(target);
+                    SpawnTeleportEvent tpEvent = new SpawnTeleportEvent(target, target.getLocation(), spawn, false);
+                    plugin.getServer().getPluginManager().callEvent(tpEvent);
+                    if (!tpEvent.isCancelled()) {
+                        target.teleport(tpEvent.getTo());
+                    }
+                }
+                LimboCache.getInstance().addLimboPlayer(target);
+                int delay = Settings.getRegistrationTimeout * 20;
+                int interval = Settings.getWarnMessageInterval;
+                BukkitScheduler scheduler = sender.getServer().getScheduler();
+                if (delay != 0) {
+                    BukkitTask id = scheduler.runTaskLaterAsynchronously(plugin, new TimeoutTask(plugin, playerNameLowerCase, target), delay);
+                    LimboCache.getInstance().getLimboPlayer(playerNameLowerCase).setTimeoutTaskId(id);
+                }
+                LimboCache.getInstance().getLimboPlayer(playerNameLowerCase).setMessageTaskId(scheduler.runTaskAsynchronously(plugin, new MessageTask(plugin, playerNameLowerCase, m.send("reg_msg"), interval)));
+                if (Settings.applyBlindEffect)
+                    target.addPotionEffect(new PotionEffect(PotionEffectType.BLINDNESS, Settings.getRegistrationTimeout * 20, 2));
+                if (!Settings.isMovementAllowed && Settings.isRemoveSpeedEnabled) {
+                    target.setWalkSpeed(0.0f);
+                    target.setFlySpeed(0.0f);
+                }
+                m.send(target, "unregistered");
+            }
+        }
+
+        // Show a status message
+        m.send(sender, "unregistered");
+        ConsoleLogger.info(playerName + " unregistered");
+        return true;
+    }
+}