Implement new command system

src/main/java/emu/grasscutter/commands/CommandMap.java

@@ -0,0 +1,87 @@
+package emu.grasscutter.commands;
+
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.game.GenshinPlayer;
+import org.reflections.Reflections;
+
+import java.util.*;
+
+@SuppressWarnings("UnusedReturnValue")
+public final class CommandMap {
+    public static CommandMap getInstance() {
+        return Grasscutter.getGameServer().getCommandMap();
+    }
+    
+    private final Map<String, CommandHandler> commands = new HashMap<>();
+
+    /**
+     * Register a command handler.
+     * @param label The command label.
+     * @param command The command handler.
+     * @return Instance chaining.
+     */
+    public CommandMap registerCommand(String label, CommandHandler command) {
+        this.commands.put(label, command); return this;
+    }
+
+    /**
+     * Removes a registered command handler.
+     * @param label The command label.
+     * @return Instance chaining.
+     */
+    public CommandMap unregisterCommand(String label) {
+        this.commands.remove(label); return this;
+    }
+
+    /**
+     * Invoke a command handler with the given arguments.
+     * @param player The player invoking the command or null for the server console.
+     * @param rawMessage The messaged used to invoke the command.
+     */
+    public void invoke(GenshinPlayer player, String rawMessage) {
+        // Remove prefix if present.
+        if(!Character.isLetter(rawMessage.charAt(0)))
+            rawMessage = rawMessage.substring(1);
+        
+        // Parse message.
+        String[] split = rawMessage.split(" ");
+        List<String> args = Arrays.asList(split);
+        String label = args.remove(0);
+        
+        // Get command handler.
+        CommandHandler handler = this.commands.get(label);
+        if(handler == null) {
+            CommandHandler.sendMessage(player, "Unknown command: " + label); return;
+        }
+        
+        // Invoke execute method for handler.
+        if(player == null)
+            handler.execute(args);
+        else handler.execute(player, args);
+    }
+    
+    public CommandMap() {
+        this(false);
+    }
+    
+    public CommandMap(boolean scan) {
+        if(scan) this.scan();
+    }
+
+    /**
+     * Scans for all classes annotated with {@link Command} and registers them.
+     */
+    private void scan() {
+        Reflections reflector = Grasscutter.reflector;
+        Set<?> classes = reflector.getTypesAnnotatedWith(Command.class);
+        classes.forEach(annotated -> {
+            try {
+                Class<?> cls = annotated.getClass();
+                Command cmdData = cls.getAnnotation(Command.class);
+                Object object = cls.getDeclaredConstructors()[0].newInstance();
+                if (object instanceof CommandHandler)
+                    this.registerCommand(cmdData.label(), (CommandHandler) object);
+            } catch (Exception ignored) { }
+        });
+    }
+}