refactor: 完善实现类

Author: ArgoZhang

src/components/BootstrapBlazor.Authenticator/Services/DefaultAuthenticatorServices.cs

@@ -7,8 +7,10 @@
 
 namespace BootstrapBlazor.Components;
 
-internal class DefaultAuthenticatorServices(IOptionsMonitor<AuthenticatorOptions> optionsMonitor) : IAuthenticatorService
+class DefaultAuthenticatorServices(IOptionsMonitor<AuthenticatorOptions> optionsMonitor) : IAuthenticatorService
 {
+    public TOTPInstance? TOTPInstance { get; private set; }
+
     public string GenerateOtpUri(AuthenticatorOptions? options = null)
     {
         options ??= optionsMonitor.CurrentValue;
@@ -17,4 +19,40 @@ public string GenerateOtpUri(AuthenticatorOptions? options = null)
         var uri = new OtpUri(type, options.SecretKey, options.UserName, options.IssuerName, mode, options.Digits, options.Period, options.Counter);
         return uri.ToString();
     }
+
+    public string ComputeTotp(string secretKey, DateTime? timestamp = null)
+    {
+        var totp = new Totp(Base32Encoding.ToBytes(secretKey));
+        TOTPInstance = new DefaultTOTPInstance(totp);
+        return timestamp == null ? totp.ComputeTotp() : totp.ComputeTotp(timestamp.Value);
+    }
+
+    public int GetRemainingSeconds(DateTime? timestamp = null)
+    {
+        if (TOTPInstance != null)
+        {
+            return timestamp == null ? TOTPInstance.GetRemainingSeconds() : TOTPInstance.GetRemainingSeconds(timestamp.Value);
+        }
+        var totp = new Totp(Base32Encoding.ToBytes("OMM2LVLFX6QJHMYI"));
+        return timestamp == null ? totp.RemainingSeconds() : totp.RemainingSeconds(timestamp.Value);
+    }
+
+    public string GenerateSecretKey(int length = 20)
+    {
+        var secretKey = KeyGeneration.GenerateRandomKey(length);
+        return Base32Encoding.ToString(secretKey);
+    }
+
+    public byte[] GetSecretKeyBytes(string input)
+    {
+        return Base32Encoding.ToBytes(input);
+    }
+}
+
+class DefaultTOTPInstance(Totp totp) : TOTPInstance
+{
+    public override int GetRemainingSeconds(DateTime? timestamp = null)
+    {
+        return timestamp == null ? totp.RemainingSeconds() : totp.RemainingSeconds(timestamp.Value);
+    }
 }