too much for one commit

src/EntKube.Clusters/Features/AdoptCluster/Components/Istio/IstioCheck.cs

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+using System.Text;
+using EntKube.Clusters.Domain;
+using k8s;
+using k8s.Models;
+using Microsoft.Extensions.Logging;
+
+namespace EntKube.Clusters.Features.AdoptCluster.Components.Istio;
+
+/// <summary>
+/// Checks whether Istio service mesh with Gateway API support is installed.
+/// The Terraform bootstrap installs three layers:
+/// 1. Gateway API CRDs (standard + experimental)
+/// 2. istio-base (Istio CRDs + namespace)
+/// 3. istiod (control plane with PILOT_ENABLE_GATEWAY_API=true)
+///
+/// This check verifies all three layers are present and healthy.
+/// </summary>
+public class IstioCheck : IAdoptionCheck
+{
+    private readonly ILogger<IstioCheck> logger;
+
+    public string ComponentName => "istio";
+    public string DisplayName => "Istio Service Mesh + Gateway API";
+
+    public IstioCheck(ILogger<IstioCheck> logger)
+    {
+        this.logger = logger;
+    }
+
+    public async Task<ComponentCheckResult> CheckAsync(KubernetesCluster cluster, CancellationToken ct = default)
+    {
+        Kubernetes client = BuildClient(cluster);
+        List<string> details = new();
+        List<string> missing = new();
+
+        // Check 1: Gateway API CRDs installed (gateways.gateway.networking.k8s.io)
+
+        bool gatewayApiCrd = await CrdExists(client, "gateways.gateway.networking.k8s.io", ct);
+
+        if (gatewayApiCrd)
+        {
+            details.Add("Gateway API CRDs present");
+        }
+        else
+        {
+            missing.Add("Gateway API CRDs not installed (gateways.gateway.networking.k8s.io)");
+        }
+
+        // Check 2: istio-system namespace with istiod pods running
+
+        List<string> istiodPods = await FindIstiodPods(client, ct);
+
+        if (istiodPods.Count > 0)
+        {
+            details.AddRange(istiodPods.Select(p => $"Pod running: {p}"));
+        }
+        else
+        {
+            missing.Add("No istiod pods found in istio-system namespace");
+        }
+
+        // Check 3: Istio CRDs (VirtualService or Gateway) — confirms istio-base installed
+
+        bool istioCrd = await CrdExists(client, "virtualservices.networking.istio.io", ct);
+
+        if (istioCrd)
+        {
+            details.Add("Istio CRDs present (networking.istio.io)");
+        }
+        else
+        {
+            missing.Add("Istio base CRDs not installed (networking.istio.io)");
+        }
+
+        // Determine status
+
+        if (istiodPods.Count == 0 && !istioCrd)
+        {
+            return new ComponentCheckResult(ComponentName, ComponentStatus.NotInstalled, details, missing);
+        }
+
+        // Discover configuration from running pods
+
+        string? version = await GetIstiodVersion(client, ct);
+
+        DiscoveredConfiguration config = new(
+            Version: version,
+            Namespace: "istio-system",
+            HelmReleaseName: "istiod",
+            Values: new Dictionary<string, string>
+            {
+                ["pilotReplicas"] = istiodPods.Count.ToString(),
+                ["gatewayApiEnabled"] = gatewayApiCrd.ToString(),
+                ["istioCrdsInstalled"] = istioCrd.ToString()
+            });
+
+        if (missing.Count > 0)
+        {
+            return new ComponentCheckResult(ComponentName, ComponentStatus.Degraded, details, missing, config);
+        }
+
+        return new ComponentCheckResult(ComponentName, ComponentStatus.Installed, details, missing, config);
+    }
+
+    private async Task<string?> GetIstiodVersion(Kubernetes client, CancellationToken ct)
+    {
+        try
+        {
+            V1PodList podList = await client.CoreV1.ListNamespacedPodAsync(
+                "istio-system", labelSelector: "app=istiod", cancellationToken: ct);
+
+            foreach (V1Pod pod in podList.Items)
+            {
+                if (pod.Spec?.Containers?.Count > 0)
+                {
+                    string? image = pod.Spec.Containers[0].Image;
+
+                    if (image?.Contains(':') == true)
+                    {
+                        return image.Split(':').Last().TrimStart('v');
+                    }
+                }
+            }
+        }
+        catch { }
+
+        return null;
+    }
+
+    private async Task<List<string>> FindIstiodPods(Kubernetes client, CancellationToken ct)
+    {
+        List<string> pods = new();
+
+        try
+        {
+            V1PodList podList = await client.CoreV1.ListNamespacedPodAsync(
+                "istio-system",
+                labelSelector: "app=istiod",
+                cancellationToken: ct);
+
+            foreach (V1Pod pod in podList.Items)
+            {
+                if (pod.Status?.Phase == "Running")
+                {
+                    pods.Add(pod.Metadata.Name);
+                }
+            }
+        }
+        catch (k8s.Autorest.HttpOperationException ex) when (ex.Response.StatusCode == System.Net.HttpStatusCode.NotFound)
+        {
+            logger.LogDebug("istio-system namespace not found");
+        }
+        catch (Exception ex)
+        {
+            logger.LogWarning(ex, "Error checking for istiod pods");
+        }
+
+        return pods;
+    }
+
+    private async Task<bool> CrdExists(Kubernetes client, string crdName, CancellationToken ct)
+    {
+        try
+        {
+            await client.ApiextensionsV1.ReadCustomResourceDefinitionAsync(crdName, cancellationToken: ct);
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static Kubernetes BuildClient(KubernetesCluster cluster)
+    {
+        byte[] kubeConfigBytes = Encoding.UTF8.GetBytes(cluster.KubeConfig);
+        using MemoryStream stream = new(kubeConfigBytes);
+        KubernetesClientConfiguration config = KubernetesClientConfiguration.BuildConfigFromConfigFile(stream, cluster.ContextName);
+        return new Kubernetes(config);
+    }
+}