Rewrite commands

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

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

@@ -0,0 +1,91 @@
+package emu.grasscutter.command.commands;
+
+import emu.grasscutter.command.Command;
+import emu.grasscutter.command.CommandHandler;
+import emu.grasscutter.command.CommandMap;
+import emu.grasscutter.game.GenshinPlayer;
+
+import java.util.*;
+
+@Command(label = "help", usage = "help [command]",
+        description = "Sends the help message or shows information about a specified command")
+public class Help implements CommandHandler {
+
+    @Override
+    public void onCommand(GenshinPlayer player, List<String> args) {
+        if (args.size() < 1) {
+            HashMap<String, CommandHandler> handlers = CommandMap.getInstance().getHandlers();
+            List<Command> annotations = new ArrayList<>();
+            for (String key : handlers.keySet()) {
+                Command annotation = handlers.get(key).getClass().getAnnotation(Command.class);
+
+                if (!Arrays.asList(annotation.aliases()).contains(key)) {
+                    if (player != null && !Objects.equals(annotation.permission(), "") && !player.getAccount().hasPermission(annotation.permission()))
+                        continue;
+                    annotations.add(annotation);
+                }
+            }
+
+            SendAllHelpMessage(player, annotations);
+        } else {
+            String command = args.get(0);
+            CommandHandler handler = CommandMap.getInstance().getHandler(command);
+            StringBuilder builder = new StringBuilder(player == null ? "\nHelp - " : "Help - ").append(command).append(": \n");
+            if (handler == null) {
+                builder.append("No command found.");
+            } else {
+                Command annotation = handler.getClass().getAnnotation(Command.class);
+
+                builder.append("   ").append(annotation.description()).append("\n");
+                builder.append("   Usage: ").append(annotation.usage());
+                if (annotation.aliases().length >= 1) {
+                    builder.append("\n").append("   Aliases: ");
+                    for (String alias : annotation.aliases()) {
+                        builder.append(alias).append(" ");
+                    }
+                }
+                if (player != null && !Objects.equals(annotation.permission(), "") && !player.getAccount().hasPermission(annotation.permission())) {
+                    builder.append("\n Warning: You do not have permission to run this command.");
+                }
+            }
+
+            CommandHandler.sendMessage(player, builder.toString());
+        }
+    }
+
+    void SendAllHelpMessage(GenshinPlayer player, List<Command> annotations) {
+        if (player == null) {
+            StringBuilder builder = new StringBuilder("\nAvailable commands:\n");
+            annotations.forEach(annotation -> {
+                builder.append(annotation.label()).append("\n");
+                builder.append("   ").append(annotation.description()).append("\n");
+                builder.append("   Usage: ").append(annotation.usage());
+                if (annotation.aliases().length >= 1) {
+                    builder.append("\n").append("   Aliases: ");
+                    for (String alias : annotation.aliases()) {
+                        builder.append(alias).append(" ");
+                    }
+                }
+
+                builder.append("\n");
+            });
+
+            CommandHandler.sendMessage(null, builder.toString());
+        } else {
+            CommandHandler.sendMessage(player, "Available commands:");
+            annotations.forEach(annotation -> {
+                StringBuilder builder = new StringBuilder(annotation.label()).append("\n");
+                builder.append("   ").append(annotation.description()).append("\n");
+                builder.append("   Usage: ").append(annotation.usage());
+                if (annotation.aliases().length >= 1) {
+                    builder.append("\n").append("   Aliases: ");
+                    for (String alias : annotation.aliases()) {
+                        builder.append(alias).append(" ");
+                    }
+                }
+
+                CommandHandler.sendMessage(player, builder.toString());
+            });
+        }
+    }
+}