Lesson 03

src/NetPulse.Cli/Program.cs

@@ -1,5 +1,6 @@
 using System.Net.NetworkInformation;
 using NetPulse.Core.Domain;
+using NetPulse.Core.Services;
 
 if (args.Length == 0)
 {
@@ -18,15 +19,32 @@ switch (command)
             return;
         }
 
-        var target = args[1];
-        await RunPingAsync(target);
-        break;
+        var service = new PingService();
+        var result = await service.RunAsync(Guid.Empty, args[1]);
+        Console.WriteLine(result.Success
+            ? $"Success: {result.LatencyMs} ms"
+            : $"Failed: {result.ErrorMessage}");
+        if (!result.Success && result.InnerErrorMessage is not null)
+        {
+            Console.WriteLine($"Inner error: {result.InnerErrorMessage}");
+        }
 
-    default:
-        Console.WriteLine($"Unkown command: {command}");
         break;
 }
+/*
+===========================================================
+ARCHIVE NOTE — Old Ping Logic (Lesson 2 → Pre-Service Layer)
+Keeping this for reference only. Not compiled. Not used.
 
+This was the original inline/local-function ping approach
+before we migrated to the proper PingService architecture.
+
+Useful for:
+- remembering how PingResult was initially populated
+- comparing exception handling approaches
+- seeing the progression of the codebase over lessons
+- nostalgia (optional but valid)
+===========================================================
 static async Task RunPingAsync(string target)
 {
     using var pinger = new Ping();
@@ -61,6 +79,7 @@ static async Task RunPingAsync(string target)
     }
 }
 
+
 static void SaveMockResult(PingResult result)
 {
     Console.WriteLine(" --- Saved Result ---");
@@ -69,3 +88,7 @@ static void SaveMockResult(PingResult result)
     Console.WriteLine($"Latency: {result.LatencyMs}");
     Console.WriteLine($"Error: {result.ErrorMessage}");
 }
+===========================================================
+End of Archive Block
+===========================================================
+*/

src/NetPulse.Core/Domain/PingResult.cs

@@ -31,4 +31,9 @@ public class PingResult
     /// Error detail if the pin failed.
     /// </summary>
     public string? ErrorMessage { get; init; } 
+
+    /// <summary>
+    /// InnerErrorMessage for error handling
+    /// </summary>
+    public string? InnerErrorMessage { get; init; }
 }

src/NetPulse.Core/Services/PingService.cs

@@ -0,0 +1,61 @@
+using System.Net.NetworkInformation;
+using NetPulse.Core.Domain;
+
+namespace NetPulse.Core.Services;
+
+public class PingService
+{
+    private readonly Ping _pinger = new();
+
+    public async Task<PingResult> RunAsync(Guid targetId, string host)
+    {
+        try
+        {
+            var reply = await _pinger.SendPingAsync(host, 2000);
+
+            if (reply.Status == IPStatus.Success)
+            {
+                return new PingResult
+                {
+                    TargetId = targetId,
+                    Timestamputc = DateTime.UtcNow,
+                    Success = true,
+                    LatencyMs = reply.RoundtripTime,
+                    ErrorMessage = null
+                };
+            }
+
+            return new PingResult
+            {
+                TargetId = targetId,
+                Timestamputc = DateTime.UtcNow,
+                Success = false,
+                LatencyMs = null,
+                ErrorMessage = $"Ping failed with status: {reply.Status}"
+            };
+        }
+        catch (PingException ex)
+        {
+            return new PingResult
+            {
+                TargetId = targetId,
+                Timestamputc = DateTime.UtcNow,
+                Success = false,
+                LatencyMs = null,
+                ErrorMessage = ex.Message,
+                InnerErrorMessage = ex.InnerException?.Message
+            };
+        }
+        catch (Exception ex)
+        {
+            return new PingResult
+            {
+                TargetId = targetId,
+                Timestamputc = DateTime.UtcNow,
+                Success = false,
+                LatencyMs = null,
+                ErrorMessage = ex.Message
+            };
+        }
+    }
+}