From a0f3ea2d3d6c411a65c7140b94588ef8991daf9d Mon Sep 17 00:00:00 2001
From: Eduardo Menezes <eduardomenezesm@msn.com>
Date: Tue, 31 Oct 2023 17:16:03 -0300
Subject: [PATCH] Enhance errors handling

---
 .../f7/Meadow.F7/F7PlatformOS.cs              | 26 +++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/source/implementations/f7/Meadow.F7/F7PlatformOS.cs b/source/implementations/f7/Meadow.F7/F7PlatformOS.cs
index 668d7bc8..acb28e94 100644
--- a/source/implementations/f7/Meadow.F7/F7PlatformOS.cs
+++ b/source/implementations/f7/Meadow.F7/F7PlatformOS.cs
@@ -93,6 +93,16 @@ public int[] GetProcessorUtilization()
         return new[] {100 - Core.Interop.Nuttx.meadow_idle_monitor_get_value()};
     }
 
+
+    /// <summary>
+    /// Enum representing different server certificate validation error returns.
+    /// </summary>
+    public enum ServerCertificateValidationError
+    {
+        InvalidMode = -1,
+        CannotChangeAfterInitialization = -2
+    }
+
     /// <inheritdoc/>
     public void SetServerCertificateValidationMode(ServerCertificateValidationMode authmode)
     {
@@ -107,12 +117,24 @@ public void SetServerCertificateValidationMode(ServerCertificateValidationMode a
         }
         
         int ret = Core.Interop.Nuttx.mono_mbedtls_set_server_cert_authmode(authModeInt);
-        if (ret < 0)
+        if (ret == (int)ServerCertificateValidationError.InvalidMode)
         {
-            string errorMessage = $"Error setting validation mode.";
+            string errorMessage = $"Invalid validation mode: {authModeInt}";
+            Resolver.Log.Error($"Invalid validation mode: {authModeInt}");
+            throw new ArgumentException(errorMessage);
+        }
+        else if (ret == (int)ServerCertificateValidationError.CannotChangeAfterInitialization)
+        {
+            string errorMessage = $"The server certificate validation mode cannot be changed after the TLS initialization.";
             Resolver.Log.Error(errorMessage);
             throw new Exception(errorMessage);
         }
+        else if (ret < 0)
+        {
+            string errorMessage = $"Error setting validation mode.";
+            Resolver.Log.Error(errorMessage);
+            throw new Exception(errorMessage); 
+        }
 
         Resolver.Log.Trace($"Server certificate validation mode set to {authmode} successfully!");