add async methods, also add separate methods which will call event and which will not call event

api/src/main/java/com/velocitypowered/api/command/CommandManager.java

@@ -1,5 +1,7 @@
 package com.velocitypowered.api.command;
 
+import java.util.concurrent.CompletableFuture;
+
 /**
  * Represents an interface to register a command executor with the proxy.
  */
@@ -34,8 +36,8 @@ public interface CommandManager {
   void unregister(String alias);
 
   /**
-   * Attempts to execute a command from the specified {@code cmdLine}.
+   * Calls CommandExecuteEvent and attempts to execute a command from the specified {@code cmdLine}
-   * CommandExecuteEvent will not called
+   * sync.
    *
    * @param source the command's source
    * @param cmdLine the command to run
@@ -44,12 +46,32 @@ public interface CommandManager {
   boolean execute(CommandSource source, String cmdLine);
 
   /**
-   * Attempts to execute a command from the specified {@code cmdLine}.
+   * Attempts to execute a command from the specified {@code cmdLine} sync
+   * without calling CommandExecuteEvent.
    *
    * @param source the command's source
    * @param cmdLine the command to run
-   * @param callEvent will CommandExecuteEvent called or not
    * @return true if the command was found and executed, false if it was not
    */
-  boolean execute(CommandSource source, String cmdLine, boolean callEvent);
+  boolean executeImmediately(CommandSource source, String cmdLine);
+
+  /**
+   * Calls CommandExecuteEvent and attempts to execute a command from the specified {@code cmdLine}
+   * async.
+   *
+   * @param source the command's source
+   * @param cmdLine the command to run
+   * @return A future that will be completed with the result of the command execution
+   */
+  CompletableFuture<Boolean> executeAsync(CommandSource source, String cmdLine);
+
+  /**
+   * Attempts to execute a command from the specified {@code cmdLine} async
+   * without calling CommandExecuteEvent.
+   *
+   * @param source the command's source
+   * @param cmdLine the command to run
+   * @return A future that will be completed with the result of the command execution
+   */
+  CompletableFuture<Boolean> executeImmediatelyAsync(CommandSource source, String cmdLine);
 }

proxy/src/main/java/com/velocitypowered/proxy/command/VelocityCommandManager.java

@@ -7,9 +7,9 @@ import com.velocitypowered.api.command.Command;
 import com.velocitypowered.api.command.CommandManager;
 import com.velocitypowered.api.command.CommandSource;
 import com.velocitypowered.api.command.RawCommand;
-import com.velocitypowered.api.event.EventManager;
 import com.velocitypowered.api.event.command.CommandExecuteEvent;
 import com.velocitypowered.api.event.command.CommandExecuteEvent.CommandResult;
+import com.velocitypowered.proxy.plugin.VelocityEventManager;
 
 import java.util.Arrays;
 import java.util.HashMap;
@@ -22,9 +22,9 @@ import java.util.concurrent.CompletableFuture;
 public class VelocityCommandManager implements CommandManager {
 
   private final Map<String, RawCommand> commands = new HashMap<>();
-  private final EventManager eventManager;
+  private final VelocityEventManager eventManager;
 
-  public VelocityCommandManager(EventManager eventManager) {
+  public VelocityCommandManager(VelocityEventManager eventManager) {
     this.eventManager = eventManager;
   }
 
@@ -74,22 +74,21 @@ public class VelocityCommandManager implements CommandManager {
     Preconditions.checkNotNull(source, "invoker");
     Preconditions.checkNotNull(cmdLine, "cmdLine");
 
-    return execute(source, cmdLine, false);
-  }
-
-  @Override
-  public boolean execute(CommandSource source, String cmdLine, boolean callEvent) {
-    Preconditions.checkNotNull(source, "invoker");
-    Preconditions.checkNotNull(cmdLine, "cmdLine");
-
-    if (callEvent) {
     CommandExecuteEvent event = callCommandEvent(source, cmdLine).join();
     CommandResult commandResult = event.getResult();
     if (commandResult.isForwardToServer() || !commandResult.isAllowed()) {
       return false;
     }
     cmdLine = commandResult.getCommand().orElse(event.getCommand());
+
+    return executeImmediately(source, cmdLine);
   }
+
+  @Override
+  public boolean executeImmediately(CommandSource source, String cmdLine) {
+    Preconditions.checkNotNull(source, "invoker");
+    Preconditions.checkNotNull(cmdLine, "cmdLine");
+
     String alias = cmdLine;
     String args = "";
     int firstSpace = cmdLine.indexOf(' ');
@@ -113,6 +112,38 @@ public class VelocityCommandManager implements CommandManager {
     }
   }
 
+
+  @Override
+  public CompletableFuture<Boolean> executeAsync(CommandSource source, String cmdLine) {
+    CompletableFuture<Boolean> result = new CompletableFuture<>();
+    callCommandEvent(source, cmdLine).thenAccept(event -> {
+      CommandResult commandResult = event.getResult();
+      if (commandResult.isForwardToServer() || !commandResult.isAllowed()) {
+        result.complete(false);
+      }
+      String command = commandResult.getCommand().orElse(event.getCommand());
+      try {
+        result.complete(executeImmediately(source, command));
+      } catch (Exception e) {
+        result.completeExceptionally(e);
+      }
+    });
+    return result;
+  }
+
+  @Override
+  public CompletableFuture<Boolean> executeImmediatelyAsync(CommandSource source, String cmdLine) {
+    CompletableFuture<Boolean> result = new CompletableFuture<>();
+    eventManager.getService().execute(() -> {
+      try {
+        result.complete(executeImmediately(source, cmdLine));
+      } catch (Exception e) {
+        result.completeExceptionally(e);
+      }
+    });
+    return result;
+  }
+
   public boolean hasCommand(String command) {
     return commands.containsKey(command);
   }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -136,7 +136,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
             }
             if (commandResult.isAllowed()) {
               try {
-                if (!server.getCommandManager().execute(player, command)) {
+                if (!server.getCommandManager().executeImmediately(player, command)) {
                   smc.write(Chat.createServerbound(command));
                 }
               } catch (Exception e) {

proxy/src/main/java/com/velocitypowered/proxy/console/VelocityConsole.java

@@ -8,6 +8,8 @@ import com.velocitypowered.api.permission.Tristate;
 import com.velocitypowered.api.proxy.ConsoleCommandSource;
 import com.velocitypowered.proxy.VelocityServer;
 import java.util.List;
+import java.util.concurrent.CompletableFuture;
+
 import net.kyori.text.Component;
 import net.kyori.text.TextComponent;
 import net.kyori.text.format.TextColor;
@@ -91,7 +93,7 @@ public final class VelocityConsole extends SimpleTerminalConsole implements Cons
   @Override
   protected void runCommand(String command) {
     try {
-      if (!this.server.getCommandManager().execute(this, command, true)) {
+      if (!this.server.getCommandManager().execute(this, command)) {
         sendMessage(TextComponent.of("Command not found.", TextColor.RED));
       }
     } catch (Exception e) {

proxy/src/main/java/com/velocitypowered/proxy/plugin/VelocityEventManager.java

@@ -185,6 +185,10 @@ public class VelocityEventManager implements EventManager {
     fireEvent(new ProxyShutdownEvent());
   }
 
+  public ExecutorService getService() {
+    return service;
+  }
+
   private static class VelocityMethodScanner implements MethodScanner<Object> {
 
     @Override