Fix some mcchat and a reset issue

Using ConcurrentHashMaps (#62)
Add custom /list to hide vanished players (#120)
Fixed /discord reset for non-Paper servers (#103)

src/main/java/buttondevteam/discordplugin/fun/FunModule.java

@@ -100,7 +100,7 @@ public class FunModule extends Component<DiscordPlugin> implements Listener {
 			ListC = 0;
 			lastlist = 0;
 		}
-		if (msglowercased.equals("list") && Bukkit.getOnlinePlayers().size() == lastlistp && ListC++ > 2) // Lowered already
+		if (msglowercased.equals("/list") && Bukkit.getOnlinePlayers().size() == lastlistp && ListC++ > 2) // Lowered already
 		{
 			DPUtils.reply(message, Mono.empty(), "stop it. You know the answer.").subscribe();
 			lastlist = 0;

src/main/java/buttondevteam/discordplugin/mcchat/MCChatCustom.java

@@ -20,9 +20,10 @@ public class MCChatCustom {
 	/**
 	 * Used for town or nation chats or anything else
 	 */
-	static ArrayList<CustomLMD> lastmsgCustom = new ArrayList<>();
+	static final ArrayList<CustomLMD> lastmsgCustom = new ArrayList<>();
 
 	public static void addCustomChat(MessageChannel channel, String groupid, Channel mcchannel, User user, DiscordConnectedPlayer dcp, int toggles, Set<TBMCSystemChatEvent.BroadcastTarget> brtoggles) {
+		synchronized (lastmsgCustom) {
 			if (mcchannel instanceof ChatRoom) {
 				((ChatRoom) mcchannel).joinRoom(dcp);
 				if (groupid == null) groupid = mcchannel.getGroupID(dcp);
@@ -30,6 +31,7 @@ public class MCChatCustom {
 			val lmd = new CustomLMD(channel, user, groupid, mcchannel, dcp, toggles, brtoggles);
 			lastmsgCustom.add(lmd);
 		}
+	}
 
 	public static boolean hasCustomChat(Snowflake channel) {
 		return lastmsgCustom.stream().anyMatch(lmd -> lmd.channel.getId().asLong() == channel.asLong());
@@ -41,6 +43,7 @@ public class MCChatCustom {
 	}
 
 	public static boolean removeCustomChat(Snowflake channel) {
+		synchronized (lastmsgCustom) {
 			MCChatUtils.lastmsgfromd.remove(channel.asLong());
 			return lastmsgCustom.removeIf(lmd -> {
 				if (lmd.channel.getId().asLong() != channel.asLong())
@@ -50,6 +53,7 @@ public class MCChatCustom {
 				return true;
 			});
 		}
+	}
 
 	public static List<CustomLMD> getCustomChats() {
 		return Collections.unmodifiableList(lastmsgCustom);

src/main/java/buttondevteam/discordplugin/mcchat/MCChatListener.java

@@ -131,6 +131,7 @@ public class MCChatListener implements Listener {
 					doit.accept(data);
 			}
 
+			synchronized (MCChatCustom.lastmsgCustom) {
 				val iterator = MCChatCustom.lastmsgCustom.iterator();
 				while (iterator.hasNext()) {
 					val lmd = iterator.next();
@@ -145,6 +146,7 @@ public class MCChatListener implements Listener {
 						}
 					}
 				}
+			}
 		} catch (InterruptedException ex) { //Stop if interrupted anywhere
 			sendtask.cancel();
 			sendtask = null;
@@ -217,7 +219,7 @@ public class MCChatListener implements Listener {
 	}
 
 	private BukkitTask rectask;
-	private LinkedBlockingQueue<MessageCreateEvent> recevents = new LinkedBlockingQueue<>();
+	private final LinkedBlockingQueue<MessageCreateEvent> recevents = new LinkedBlockingQueue<>();
 	private Runnable recrun;
 	private static Thread recthread;
 
@@ -368,6 +370,7 @@ public class MCChatListener implements Listener {
 			return true;
 		}
 		module.log(dsender.getName() + " ran from DC: /" + cmd);
+		if (runCustomCommand(dsender, cmdlowercased)) return true;
 		val channel = clmd == null ? user.channel().get() : clmd.mcchannel;
 		val ev = new TBMCCommandPreprocessEvent(dsender, channel, dmessage, clmd == null ? dsender : clmd.dcp);
 		Bukkit.getScheduler().runTask(DiscordPlugin.plugin, //Commands need to be run sync
@@ -396,6 +399,17 @@ public class MCChatListener implements Listener {
 		return true;
 	}
 
+	private boolean runCustomCommand(DiscordSenderBase dsender, String cmdlowercased) {
+		if (cmdlowercased.startsWith("list")) {
+			var players = Bukkit.getOnlinePlayers();
+			dsender.sendMessage("There are " + players.size() + " out of " + Bukkit.getMaxPlayers() + " players online.");
+			dsender.sendMessage("Players: " + players.stream().filter(MCChatUtils::checkEssentials)
+				.map(Player::getDisplayName).collect(Collectors.joining(", ")));
+			return true;
+		}
+		return false;
+	}
+
 	@FunctionalInterface
 	private interface InterruptibleConsumer<T> {
 		void accept(T value) throws TimeoutException, InterruptedException;

src/main/java/buttondevteam/discordplugin/mcchat/MCChatPrivate.java

@@ -20,6 +20,7 @@ public class MCChatPrivate {
 	static ArrayList<MCChatUtils.LastMsgData> lastmsgPerUser = new ArrayList<>();
 
 	public static boolean privateMCChat(MessageChannel channel, boolean start, User user, DiscordPlayer dp) {
+		synchronized (MCChatUtils.ConnectedSenders) {
 			TBMCPlayer mcp = dp.getAs(TBMCPlayer.class);
 			if (mcp != null) { // If the accounts aren't connected, can't make a connected sender
 				val p = Bukkit.getPlayer(mcp.getUUID());
@@ -47,6 +48,7 @@ public class MCChatPrivate {
 				? lastmsgPerUser.add(new MCChatUtils.LastMsgData(channel, user)) // Doesn't support group DMs
 				: lastmsgPerUser.removeIf(lmd -> lmd.channel.getId().asLong() == channel.getId().asLong());
 		}
+	}
 
 	public static boolean isMinecraftChatEnabled(DiscordPlayer dp) {
 		return isMinecraftChatEnabled(dp.getDiscordID());
@@ -59,11 +61,13 @@ public class MCChatPrivate {
 	}
 
 	public static void logoutAll() {
+		synchronized (MCChatUtils.ConnectedSenders) {
 			for (val entry : MCChatUtils.ConnectedSenders.entrySet())
 				for (val valueEntry : entry.getValue().entrySet())
 					if (MCChatUtils.getSender(MCChatUtils.OnlineSenders, valueEntry.getKey(), valueEntry.getValue().getUser()) == null) //If the player is online then the fake player was already logged out
 						MCChatUtils.callLogoutEvent(valueEntry.getValue(), false); //This is sync
 			MCChatUtils.ConnectedSenders.clear();
 		}
+	}
 
 }

src/main/java/buttondevteam/discordplugin/mcchat/MCChatUtils.java

@@ -34,6 +34,7 @@ import reactor.core.publisher.Mono;
 import javax.annotation.Nullable;
 import java.net.InetAddress;
 import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
@@ -45,13 +46,13 @@ public class MCChatUtils {
 	/**
 	 * May contain P<DiscordID> as key for public chat
 	 */
-	public static final HashMap<String, HashMap<Snowflake, DiscordSender>> UnconnectedSenders = new HashMap<>();
+	public static final ConcurrentHashMap<String, ConcurrentHashMap<Snowflake, DiscordSender>> UnconnectedSenders = new ConcurrentHashMap<>();
-	public static final HashMap<String, HashMap<Snowflake, DiscordConnectedPlayer>> ConnectedSenders = new HashMap<>();
+	public static final ConcurrentHashMap<String, ConcurrentHashMap<Snowflake, DiscordConnectedPlayer>> ConnectedSenders = new ConcurrentHashMap<>();
 	/**
 	 * May contain P&lt;DiscordID&gt; as key for public chat
 	 */
-	public static final HashMap<String, HashMap<Snowflake, DiscordPlayerSender>> OnlineSenders = new HashMap<>();
+	public static final ConcurrentHashMap<String, ConcurrentHashMap<Snowflake, DiscordPlayerSender>> OnlineSenders = new ConcurrentHashMap<>();
-	public static final HashMap<UUID, DiscordConnectedPlayer> LoggedInPlayers = new HashMap<>();
+	public static final ConcurrentHashMap<UUID, DiscordConnectedPlayer> LoggedInPlayers = new ConcurrentHashMap<>();
 	static @Nullable LastMsgData lastmsgdata;
 	static LongObjectHashMap<Message> lastmsgfromd = new LongObjectHashMap<>(); // Last message sent by a Discord user, used for clearing checkmarks
 	private static MinecraftChatModule module;
@@ -104,28 +105,28 @@ public class MCChatUtils {
 		((TextChannel) lmd.channel).edit(tce -> tce.setTopic(String.join("\n----\n", s)).setReason("Player list update")).subscribe(); //Don't wait
 	}
 
-	private static boolean checkEssentials(Player p) {
+	static boolean checkEssentials(Player p) {
 		var ess = MainPlugin.ess;
 		if (ess == null) return true;
 		return !ess.getUser(p).isHidden();
 	}
 
-	public static <T extends DiscordSenderBase> T addSender(HashMap<String, HashMap<Snowflake, T>> senders,
+	public static <T extends DiscordSenderBase> T addSender(ConcurrentHashMap<String, ConcurrentHashMap<Snowflake, T>> senders,
 	                                                        User user, T sender) {
 		return addSender(senders, user.getId().asString(), sender);
 	}
 
-	public static <T extends DiscordSenderBase> T addSender(HashMap<String, HashMap<Snowflake, T>> senders,
+	public static <T extends DiscordSenderBase> T addSender(ConcurrentHashMap<String, ConcurrentHashMap<Snowflake, T>> senders,
 	                                                        String did, T sender) {
 		var map = senders.get(did);
 		if (map == null)
-			map = new HashMap<>();
+			map = new ConcurrentHashMap<>();
 		map.put(sender.getChannel().getId(), sender);
 		senders.put(did, map);
 		return sender;
 	}
 
-	public static <T extends DiscordSenderBase> T getSender(HashMap<String, HashMap<Snowflake, T>> senders,
+	public static <T extends DiscordSenderBase> T getSender(ConcurrentHashMap<String, ConcurrentHashMap<Snowflake, T>> senders,
 	                                                        Snowflake channel, User user) {
 		var map = senders.get(user.getId().asString());
 		if (map != null)
@@ -133,7 +134,7 @@ public class MCChatUtils {
 		return null;
 	}
 
-	public static <T extends DiscordSenderBase> T removeSender(HashMap<String, HashMap<Snowflake, T>> senders,
+	public static <T extends DiscordSenderBase> T removeSender(ConcurrentHashMap<String, ConcurrentHashMap<Snowflake, T>> senders,
 	                                                           Snowflake channel, User user) {
 		var map = senders.get(user.getId().asString());
 		if (map != null)

src/main/java/buttondevteam/discordplugin/mccommands/DiscordMCCommand.java

@@ -74,7 +74,7 @@ public class DiscordMCCommand extends ICommand2MC {
 		"This command disables and then enables the plugin." //
 	})
 	public void reset(CommandSender sender) {
-		Bukkit.getScheduler().runTaskAsynchronously(DiscordPlugin.plugin, () -> {
+		Runnable task = () -> {
 			if (!DiscordPlugin.plugin.tryReloadConfig()) {
 				sender.sendMessage("§cFailed to reload config so not resetting. Check the console.");
 				return;
@@ -87,7 +87,12 @@ public class DiscordMCCommand extends ICommand2MC {
 			Bukkit.getPluginManager().enablePlugin(DiscordPlugin.plugin);
 			if (!(sender instanceof DiscordSenderBase)) //Sending to Discord errors
 				sender.sendMessage("§bReset finished!");
-		});
+		};
+		if (!Bukkit.getName().equals("Paper")) {
+			getPlugin().getLogger().warning("Async plugin events are not supported by the server, running on main thread");
+			Bukkit.getScheduler().runTask(DiscordPlugin.plugin, task);
+		} else
+			Bukkit.getScheduler().runTaskAsynchronously(DiscordPlugin.plugin, task);
 	}
 
 	@Command2.Subcommand(helpText = {