Changed to use a separate account for each email address.

Common/Database/Account/AccountData.cs

@@ -26,11 +26,14 @@ public class AccountData : BaseDatabaseDataHelper
         AccountData? result = null;
         DatabaseHelper.GetAllInstance<AccountData>()?.ForEach(account =>
         {
-            if (account.Username == username) result = account;
+            if (string.Equals(account.Username, username, StringComparison.OrdinalIgnoreCase)) result = account;
         });
         return result;
     }
 
+    public static AccountData? GetAccountByEmail(string email)
+        => GetAccountByUserName(email);
+
     public static AccountData? GetAccountByUid(int uid, bool force = false)
     {
         var result = DatabaseHelper.GetInstance<AccountData>(uid, force);
@@ -61,8 +64,15 @@ public class AccountData : BaseDatabaseDataHelper
 
     #region Account
 
-    public static void CreateAccount(string username, int uid, string password)
+    public static AccountData CreateAccount(string username, int uid, string password)
     {
+        if (string.IsNullOrWhiteSpace(username))
+            throw new ArgumentException("Username cannot be empty.", nameof(username));
+        if (GetAccountByUserName(username) != null)
+            throw new InvalidOperationException($"Account '{username}' already exists.");
+        if (uid != 0 && GetAccountByUid(uid) != null)
+            throw new InvalidOperationException($"UID '{uid}' is already in use.");
+
         var newUid = uid;
         if (uid == 0)
         {
@@ -84,6 +94,7 @@ public class AccountData : BaseDatabaseDataHelper
         SetPassword(account, password);
 
         DatabaseHelper.CreateInstance(account);
+        return account;
     }
 
     public static void DeleteAccount(int uid)
@@ -178,4 +189,4 @@ public class AccountData : BaseDatabaseDataHelper
     }
 
     #endregion
-}
+}

Common/Internationalization/Message/LanguageCHS.cs

@@ -128,6 +128,7 @@ public class CommandTextCHS
 {
     public NoticeTextCHS Notice { get; } = new();
     public HelpTextCHS Help { get; } = new();
+    public AccountTextCHS Account { get; } = new();
     public GirlTextCHS Girl { get; } = new();
     public GiveAllTextCHS GiveAll { get; } = new();
     public DebugTextCHS Debug { get; } = new();
@@ -218,6 +219,14 @@ public class HelpTextCHS
     public string CommandAlias => "命令别名: ";
 }
 
+public class AccountTextCHS
+{
+    public string Desc => "管理 SDK 登录使用的账号映射";
+    public string Usage => "用法: /account create <邮箱> <UID>";
+    public string Created => "已创建账号映射: {0} -> UID {1}";
+    public string CreateFailed => "创建账号映射失败: {0}";
+}
+
 /// <summary>
 ///     path: Game.Command.Girl
 /// </summary>

Common/Internationalization/Message/LanguageCHT.cs

@@ -128,6 +128,7 @@ public class CommandTextCHT
 {
     public NoticeTextCHT Notice { get; } = new();
     public HelpTextCHT Help { get; } = new();
+    public AccountTextCHT Account { get; } = new();
     public GirlTextCHT Girl { get; } = new();
     public GiveAllTextCHT GiveAll { get; } = new();
     public DebugTextCHT Debug { get; } = new();
@@ -218,6 +219,14 @@ public class HelpTextCHT
     public string CommandAlias => "命令別名: ";
 }
 
+public class AccountTextCHT
+{
+    public string Desc => "管理 SDK 登入使用的帳號映射";
+    public string Usage => "用法: /account create <郵箱> <UID>";
+    public string Created => "已建立帳號映射: {0} -> UID {1}";
+    public string CreateFailed => "建立帳號映射失敗: {0}";
+}
+
 /// <summary>
 ///     path: Game.Command.Girl
 /// </summary>

Common/Internationalization/Message/LanguageEN.cs

@@ -87,6 +87,7 @@ public class CommandTextEN
 {
     public NoticeTextEN Notice { get; } = new();
     public HelpTextEN Help { get; } = new();
+    public AccountTextEN Account { get; } = new();
     public GirlTextEN Girl { get; } = new();
     public GiveAllTextEN GiveAll { get; } = new();
     public DebugTextEN Debug { get; } = new();
@@ -184,6 +185,14 @@ public class HelpTextEN
     public string CommandAlias => "Command Alias：";
 }
 
+public class AccountTextEN
+{
+    public string Desc => "Manage account mappings for SDK logins";
+    public string Usage => "Usage: /account create <email> <uid>";
+    public string Created => "Created account mapping: {0} -> UID {1}";
+    public string CreateFailed => "Failed to create account mapping: {0}";
+}
+
 /// <summary>
 ///     path: Game.Command.Girl
 /// </summary>