Rewrite commands

Signed-off-by: Jaida Wu <mlgmxyysd@meowcat.org>

src/main/java/emu/grasscutter/command/commands/Broadcast.java

@@ -0,0 +1,29 @@
+package emu.grasscutter.command.commands;
+
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.command.Command;
+import emu.grasscutter.command.CommandHandler;
+import emu.grasscutter.game.GenshinPlayer;
+
+import java.util.List;
+
+@Command(label = "broadcast", usage = "broadcast <message>",
+        description = "Sends a message to all the players", aliases = {"b"}, permission = "server.broadcast")
+public class Broadcast implements CommandHandler {
+
+    @Override
+    public void onCommand(GenshinPlayer sender, List<String> args) {
+        if (args.size() < 1) {
+            CommandHandler.sendMessage(sender, "Usage: broadcast <message>");
+            return;
+        }
+
+        String message = String.join(" ", args.subList(0, args.size()));
+
+        for (GenshinPlayer p : Grasscutter.getGameServer().getPlayers().values()) {
+            CommandHandler.sendMessage(p, message);
+        }
+
+        CommandHandler.sendMessage(sender, "Message sent.");
+    }
+}