+/// <summary>
+/// Attempts to log in to the bot service using password authentication, falling back to QR code if necessary.
+/// </summary>
+/// <param name="app">The YounBot application instance.</param>
+/// <param name="config">The bot configuration.</param>
+/// <param name="deviceInfo">Device information for the bot.</param>
+/// <param name="keystore">The bot keystore.</param>
+/// <returns>A task representing the asynchronous login operation.</returns>
+/// <exception cref="ArgumentNullException">Thrown when any parameter is null.</exception>
 public static async Task Login(YounBotApp app, BotConfig config, BotDeviceInfo deviceInfo, BotKeystore keystore)
 {
+    ArgumentNullException.ThrowIfNull(app);
+    ArgumentNullException.ThrowIfNull(config);
+    ArgumentNullException.ThrowIfNull(deviceInfo);
+    ArgumentNullException.ThrowIfNull(keystore);

-    app.Client = BotFactory.Create(config, deviceInfo, keystore);
-    var client = app.Client;
+    try 
+    {
+        app.Client = BotFactory.Create(config, deviceInfo, keystore);
+        var client = app.Client;
+    }
+    catch (Exception ex)
+    {
+        throw new InvalidOperationException("Failed to create bot client.", ex);
+    }

+    private static readonly string DefaultKeystorePath = "keystore.json";
+    private static void OnBotLog(object? sender, BotLogEvent @event)
+    {
+        Console.WriteLine(@event.ToString());
+    }
+
+    private static void OnBotOnline(object? sender, BotOnlineEvent @event, IBotClient client, 
+        BotKeystore keystore, IConfiguration configuration)
+    {
+        Console.WriteLine(@event.ToString());
+        client.UpdateKeystore();
+        try
+        {
+            var keystorePath = configuration["ConfigPath:Keystore"] ?? DefaultKeystorePath;
+            File.WriteAllText(keystorePath, JsonSerializer.Serialize(keystore));
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"Failed to save keystore: {ex.Message}");
+        }
+    }
+
     // In Login method:
-    client.Invoker.OnBotLogEvent += (_, @event) => {
-        Console.WriteLine(@event.ToString());
-    };
+    client.Invoker.OnBotLogEvent += OnBotLog;
     
-    client.Invoker.OnBotOnlineEvent += (_, @event) =>
-    {
-        Console.WriteLine(@event.ToString());
-        client.UpdateKeystore();
-        File.WriteAllText(app.Configuration["ConfigPath:Keystore"] ?? "keystore.json", 
-            JsonSerializer.Serialize(keystore));
-    };
+    client.Invoker.OnBotOnlineEvent += (s, e) => 
+        OnBotOnline(s, e, client, keystore, app.Configuration);

+    private static readonly string QrCodePath = "qrcode.png";
+    private static readonly TimeSpan LoginTimeout = TimeSpan.FromMinutes(2);
+
     // In Login method:
-    if (!await app.Client.LoginByPassword())
+    using var cts = new CancellationTokenSource(LoginTimeout);
+    try
     {
-        var qrCode = await client.FetchQrCode();
-
-        if (qrCode != null)
+        if (!await app.Client.LoginByPassword().WaitAsync(cts.Token))
         {
-            await File.WriteAllBytesAsync("qrcode.png", qrCode.Value.QrCode);
-            await app.Client.LoginByQrCode();
+            var qrCode = await client.FetchQrCode().WaitAsync(cts.Token);
+
+            if (qrCode != null)
+            {
+                try
+                {
+                    await File.WriteAllBytesAsync(QrCodePath, qrCode.Value.QrCode);
+                    await app.Client.LoginByQrCode().WaitAsync(cts.Token);
+                }
+                finally
+                {
+                    if (File.Exists(QrCodePath))
+                    {
+                        File.Delete(QrCodePath);
+                    }
+                }
+            }
+            else
+            {
+                throw new InvalidOperationException("Failed to fetch QR code.");
+            }
         }
     }
+    catch (OperationCanceledException)
+    {
+        throw new TimeoutException("Login operation timed out.");
+    }

-            using var istr = assm.GetManifestResourceStream("YounBot.Resources.appsettings.json")!;
+            var resourceStream = assm.GetManifestResourceStream("YounBot.Resources.appsettings.json");
+            if (resourceStream == null)
+            {
+                throw new FileNotFoundException("Required embedded resource 'appsettings.json' was not found. Ensure it's properly embedded in the assembly.");
+            }
+            using var istr = resourceStream;

        var appBuilder = new YounBotAppBuilder(configuration);
        var app = appBuilder.Build();
        appBuilder.ConfigureBots();

        //登录
-        await QrCodeLogin.Login(app, appBuilder.GetConfig(), appBuilder.GetDeviceInfo(), appBuilder.GetKeystore());
+        try 
+        {
+            await QrCodeLogin.Login(app, appBuilder.GetConfig(), appBuilder.GetDeviceInfo(), appBuilder.GetKeystore());
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"Login failed: {ex.Message}");
+            // Consider adding proper logging and graceful shutdown
+            Environment.Exit(1);
+        }

-public class YounBotApp(YounBotAppBuilder appBuilder)
+public class YounBotApp(YounBotAppBuilder appBuilder)
+{
+    public YounBotApp(YounBotAppBuilder appBuilder)
+    {
+        ArgumentNullException.ThrowIfNull(appBuilder);
+        Configuration = appBuilder.GetConfiguration();
+    }

-public sealed class YounBotAppBuilder(IConfiguration configuration)
+public sealed class YounBotAppBuilder
+{
+    private readonly IConfiguration configuration;
+
+    public YounBotAppBuilder(IConfiguration configuration)
+    {
+        this.configuration = configuration;
+    }
+
+    // Rest of the class...

-AutoReconnect = bool.Parse(configuration["Account:AutoReconnect"] ?? "true"),
+if (!bool.TryParse(configuration["Account:AutoReconnect"], out var autoReconnect))
+{
+    autoReconnect = true; // Default value
+}
+AutoReconnect = autoReconnect;

-UseIPv6Network = bool.Parse(configuration["Account:UseIPv6Network"] ?? "false"),
+if (!bool.TryParse(configuration["Account:UseIPv6Network"], out var useIPv6Network))
+{
+    useIPv6Network = false; // Default value
+}
+UseIPv6Network = useIPv6Network;

-GetOptimumServer = bool.Parse(configuration["Account:GetOptimumServer"] ?? "true"),
+if (!bool.TryParse(configuration["Account:GetOptimumServer"], out var getOptimumServer))
+{
+    getOptimumServer = true; // Default value
+}
+GetOptimumServer = getOptimumServer;

-AutoReLogin = bool.Parse(configuration["Account:AutoReLogin"] ?? "true"),
+if (!bool.TryParse(configuration["Account:AutoReLogin"], out var autoReLogin))
+{
+    autoReLogin = true; // Default value
+}
+AutoReLogin = autoReLogin;

- _keystore = JsonSerializer.Deserialize<BotKeystore>(File.ReadAllText(keystorePath)) ?? new BotKeystore();
+ try
+ {
+     _keystore = JsonSerializer.Deserialize<BotKeystore>(File.ReadAllText(keystorePath)) ?? new BotKeystore();
+ }
+ catch (Exception ex)
+ {
+     // Log the exception if necessary
+     // Initialize with a new instance to prevent null reference issues
+     _keystore = new BotKeystore();
+ }

- _deviceInfo = JsonSerializer.Deserialize<BotDeviceInfo>(File.ReadAllText(deviceInfoPath)) ?? BotDeviceInfo.GenerateInfo();
+ try
+ {
+     _deviceInfo = JsonSerializer.Deserialize<BotDeviceInfo>(File.ReadAllText(deviceInfoPath)) ?? BotDeviceInfo.GenerateInfo();
+ }
+ catch (Exception ex)
+ {
+     // Log the exception if necessary
+     // Generate new device info to prevent null reference issues
+     _deviceInfo = BotDeviceInfo.GenerateInfo();
+ }