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Source/MQTTnet.PowerShell/Cmdlets/ReceiveMqttMessageCmdlet.cs

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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Management.Automation;
+
+namespace MQTTnet.PowerShell.Cmdlets;
+
+[Cmdlet(VerbsCommunications.Receive, "MqttMessage")]
+[OutputType(typeof(MqttMessage))]
+public class ReceiveMqttMessageCmdlet : PSCmdlet
+{
+    [Parameter(Mandatory = true, ValueFromPipeline = true)]
+    public required MqttSession Session { get; set; }
+
+    [Parameter]
+    [ValidateRange(0, int.MaxValue)]
+    public int TimeoutSeconds { get; set; } = 0;
+
+    protected override void ProcessRecord()
+    {
+        var tcs = new TaskCompletionSource<MqttMessage>();
+        EventHandler<MqttMessage>? handler = null;
+        CancellationTokenSource? cts = null;
+
+        try
+        {
+            handler = (s, e) =>
+            {
+                if (!tcs.Task.IsCompleted)
+                {
+                    tcs.TrySetResult(e);
+                }
+            };
+
+            Session.MessageReceived += handler;
+
+            // Optionaler Timeout
+            if (TimeoutSeconds > 0)
+            {
+                cts = new CancellationTokenSource();
+                cts.CancelAfter(TimeSpan.FromSeconds(TimeoutSeconds));
+                cts.Token.Register(() =>
+                {
+                    if (!tcs.Task.IsCompleted)
+                    {
+                        tcs.TrySetCanceled();
+                    }
+                });
+            }
+
+            WriteVerbose("Waiting for next MQTT message...");
+
+            try
+            {
+                var message = tcs.Task.GetAwaiter().GetResult();
+                WriteObject(message);
+            }
+            catch (TaskCanceledException)
+            {
+                WriteWarning($"Timeout after {TimeoutSeconds} seconds — no message received.");
+            }
+        }
+        finally
+        {
+            if (handler != null)
+            {
+                Session.MessageReceived -= handler;
+            }
+
+            cts?.Dispose();
+        }
+    }
+}