feat(ban): Implementing `ban`.

Rough code, not based on permission.

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

+package emu.grasscutter.command.commands;
+
+import java.util.List;
+
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.command.Command;
+import emu.grasscutter.command.CommandHandler;
+import emu.grasscutter.database.DatabaseHelper;
+import emu.grasscutter.game.Account;
+import emu.grasscutter.game.player.Player;
+
+import static emu.grasscutter.utils.Language.translate;
+
+@Command(
+    label = "ban",
+    usage = "ban <player> [time] [reason]",
+    description = "commands.ban.description",
+    targetRequirement = Command.TargetRequirement.NONE
+)
+public final class BanCommand implements CommandHandler {
+
+    private boolean banAccount(int uid, int time, String reason) {
+        Player player = Grasscutter.getGameServer().getPlayerByUid(uid, true);
+
+        if (player == null) {
+            return false;
+        }
+
+        Account account = player.getAccount();
+        if (account == null) {
+            account = DatabaseHelper.getAccountByPlayerId(uid);
+        }
+
+        account.setBanReason(reason);
+        account.setBanEndTime(time);
+        account.setBanStartTime((int) System.currentTimeMillis() / 1000);
+        account.setBanned(true);
+        account.save();
+
+        Player banUser = Grasscutter.getGameServer().getPlayerByUid(uid);
+
+        if (banUser != null) {
+            banUser.getSession().close();
+        }
+        return true;
+    }
+
+    @Override
+    public void execute(Player sender, Player targetPlayer, List<String> args) {
+        if (args.size() < 1) {
+            CommandHandler.sendMessage(sender, translate(sender, "commands.ban.command_usage"));
+            return;
+        }
+
+        int uid = 0;
+        int time = 2051190000;
+        String reason = "Reason not specified.";
+
+        if (args.size() >= 1) {
+            try {
+                uid = Integer.parseInt(args.get(0));
+            } catch (NumberFormatException ignored) {
+                CommandHandler.sendMessage(sender, translate(sender, "commands.ban.invalid_player_id"));
+                return;
+            }
+        }
+
+        if (args.size() >= 2) {
+            try {
+                time = Integer.parseInt(args.get(1));
+            } catch (NumberFormatException ignored) {
+                CommandHandler.sendMessage(sender, translate(sender, "commands.ban.invalid_time"));
+                return;
+            }
+        }
+
+        if (args.size() >= 3) {
+            reason = args.get(2);
+        }
+
+        if (banAccount(uid, time, reason)) {
+            CommandHandler.sendMessage(sender, translate(sender, "commands.ban.success"));
+        } else {
+            CommandHandler.sendMessage(sender, translate(sender, "commands.ban.failure"));
+        }
+    }
+}
\ No newline at end of file

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

+package emu.grasscutter.command.commands;
+
+import java.util.List;
+
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.command.Command;
+import emu.grasscutter.command.CommandHandler;
+import emu.grasscutter.database.DatabaseHelper;
+import emu.grasscutter.game.Account;
+import emu.grasscutter.game.player.Player;
+
+import static emu.grasscutter.utils.Language.translate;
+
+@Command(
+    label = "unban",
+    usage = "unban <player>",
+    description = "commands.unban.description",
+    targetRequirement = Command.TargetRequirement.NONE
+)
+public final class UnBanCommand implements CommandHandler {
+
+    private boolean unBanAccount(int uid) {
+        Player player = Grasscutter.getGameServer().getPlayerByUid(uid, true);
+
+        if (player == null) {
+            return false;
+        }
+
+        Account account = player.getAccount();
+
+        if (account == null) {
+            account = DatabaseHelper.getAccountByPlayerId(uid);
+        }
+
+        account.setBanReason(null);
+        account.setBanEndTime(0);
+        account.setBanStartTime(0);
+        account.setBanned(false);
+        account.save();
+
+        return true;
+    }
+
+    @Override
+    public void execute(Player sender, Player targetPlayer, List<String> args) {
+        if (args.size() < 1) {
+            CommandHandler.sendMessage(sender, translate(sender, "commands.unban.command_usage"));
+            return;
+        }
+
+        int uid = 0;
+
+        try {
+            uid = Integer.parseInt(args.get(0));
+        } catch (NumberFormatException ignored) {
+            CommandHandler.sendMessage(sender, translate(sender, "commands.unban.invalid_player_id"));
+            return;
+        }
+
+        if (unBanAccount(uid)) {
+            CommandHandler.sendMessage(sender, translate(sender, "commands.unban.success"));
+        } else {
+            CommandHandler.sendMessage(sender, translate(sender, "commands.unban.failure"));
+        }
+    }
+}
\ No newline at end of file

src/main/java/emu/grasscutter/game/Account.java

@@ -29,6 +29,11 @@ public class Account {
 	private List<String> permissions;
     private Locale locale;
 
+	private String banReason;
+	private int banEndTime;
+	private int banStartTime;
+	private boolean isBanned;
+	
 	@Deprecated
 	public Account() {
 		this.permissions = new ArrayList<>();
@@ -105,6 +110,46 @@ public class Account {
         this.locale = locale;
     }
 
+	public String getBanReason() {
+		return banReason;
+	}
+
+	public void setBanReason(String banReason) {
+		this.banReason = banReason;
+	}
+
+	public int getBanEndTime() {
+		return banEndTime;
+	}
+
+	public void setBanEndTime(int banEndTime) {
+		this.banEndTime = banEndTime;
+	}
+
+	public int getBanStartTime() {
+		return banStartTime;
+	}
+
+	public void setBanStartTime(int banStartTime) {
+		this.banStartTime = banStartTime;
+	}
+
+	public boolean isBanned() {
+		if (banEndTime > 0 && banEndTime < System.currentTimeMillis() / 1000) {
+			this.isBanned = false;
+			this.banEndTime = 0;
+			this.banStartTime = 0;
+			this.banReason = null;
+			save();
+		}
+
+		return isBanned;
+	}
+
+	public void setBanned(boolean isBanned) {
+		this.isBanned = isBanned;
+	}
+
 	/**
 	 * The collection of a player's permissions.
 	 */

src/main/java/emu/grasscutter/server/packet/send/PacketGetPlayerTokenRsp.java

 package emu.grasscutter.server.packet.send;
 
+import java.util.Base64;
+
 import com.google.protobuf.ByteString;
 
 import emu.grasscutter.net.packet.BasePacket;
@@ -15,6 +17,23 @@ public class PacketGetPlayerTokenRsp extends BasePacket {
 		
 		this.setUseDispatchKey(true);
 
+		if (session.getPlayer().getAccount().isBanned()) {
+			byte[] bin = Base64.getDecoder().decode("5LiN54ixIEdDIOWNgeW5tOS6hu+8jOWNgeW5tOmHjOeUqOi/h+eahOavj+S4gOS4qiBQUyDpg73lg48gR0PjgII=");
+
+			GetPlayerTokenRsp p = GetPlayerTokenRsp.newBuilder()
+				.setUid(session.getPlayer().getUid())
+				.setIsProficientPlayer(session.getPlayer().getAvatars().getAvatarCount() > 0)
+				.setRetcode(21)
+				.setExtraBinData(ByteString.copyFrom(bin))
+				.setMsg("FORBID_CHEATING_PLUGINS")
+				.setBlackUidEndTime(session.getPlayer().getAccount().getBanEndTime())
+				.setRegPlatform(3)
+				.setCountryCode("US")
+				.setClientIpStr(session.getAddress().getAddress().getHostAddress())
+				.build();
+			
+			this.setData(p.toByteArray());
+		} else {
 			GetPlayerTokenRsp p = GetPlayerTokenRsp.newBuilder()
 				.setUid(session.getPlayer().getUid())
 				.setToken(session.getAccount().getToken())
@@ -33,3 +52,4 @@ public class PacketGetPlayerTokenRsp extends BasePacket {
 			this.setData(p.toByteArray());
 		}
 	}
+}

src/main/resources/languages/en-US.json

@@ -391,6 +391,21 @@
       "success": "Changed climate type to %s with weather type %s.",
       "invalid_id": "Invalid ID.",
       "description": "Changes the weather"
+    },
+    "ban": {
+      "description": "Ban a player",
+      "success": "Successful.",
+      "failure": "Failed, player not found.",
+      "invalid_time": "Unable to parse timestamp.",
+      "invalid_player_id": "Unable to parse player ID.",
+      "command_usage": "Usage: ban <playerId> [timestamp] [reason]"
+    },
+    "unban": {
+      "description": "Unban a player",
+      "success": "Successful.",
+      "failure": "Failed, player not found.",
+      "invalid_player_id": "Unable to parse player ID.",
+      "command_usage": "Usage: unban <playerId>"
     }
   },
   "gacha": {

src/main/resources/languages/zh-CN.json

@@ -391,6 +391,21 @@
       "success": "已更改气候类型为 %s，天气类型为 %s。",
       "invalid_id": "无效的ID。",
       "description": "更改天气"
+    },
+    "ban": {
+      "description": "封禁玩家",
+      "success": "封禁玩家成功。",
+      "failure": "封禁玩家失败，因为无法获取到其账户。",
+      "invalid_time": "无法解析时间戳。",
+      "invalid_player_id": "无法解析玩家 ID。",
+      "command_usage": "用法：ban <玩家ID> [时间] [原因]"
+    },
+    "unban": {
+      "description": "取消玩家的封禁",
+      "success": "取消玩家的封禁成功。",
+      "failure": "取消玩家的封禁失败，因为无法获取到其账户。",
+      "invalid_player_id": "无法解析玩家 ID。",
+      "command_usage": "用法：unban <玩家ID>"
     }
   },
   "gacha": {