Restructure solution layout by module

src/Zastava/StellaOps.Zastava.Webhook/Certificates/IWebhookCertificateProvider.cs

@@ -0,0 +1,49 @@
+using System.Security.Cryptography.X509Certificates;
+using Microsoft.Extensions.Options;
+using StellaOps.Zastava.Webhook.Configuration;
+
+namespace StellaOps.Zastava.Webhook.Certificates;
+
+public interface IWebhookCertificateProvider
+{
+    X509Certificate2 GetCertificate();
+}
+
+public sealed class WebhookCertificateProvider : IWebhookCertificateProvider
+{
+    private readonly ILogger<WebhookCertificateProvider> _logger;
+    private readonly ZastavaWebhookTlsOptions _options;
+    private readonly Lazy<X509Certificate2> _certificate;
+    private readonly IWebhookCertificateSource _certificateSource;
+
+    public WebhookCertificateProvider(
+        IOptions<ZastavaWebhookOptions> options,
+        IEnumerable<IWebhookCertificateSource> certificateSources,
+        ILogger<WebhookCertificateProvider> logger)
+    {
+        _logger = logger;
+        _options = options.Value.Tls;
+        _certificateSource = certificateSources.FirstOrDefault(source => source.CanHandle(_options.Mode))
+            ?? throw new InvalidOperationException($"No certificate source registered for mode {_options.Mode}.");
+
+        _certificate = new Lazy<X509Certificate2>(LoadCertificate, LazyThreadSafetyMode.ExecutionAndPublication);
+    }
+
+    public X509Certificate2 GetCertificate() => _certificate.Value;
+
+    private X509Certificate2 LoadCertificate()
+    {
+        _logger.LogInformation("Loading webhook TLS certificate using {Mode} mode.", _options.Mode);
+        var certificate = _certificateSource.LoadCertificate(_options);
+        _logger.LogInformation("Loaded webhook TLS certificate with subject {Subject} and thumbprint {Thumbprint}.",
+            certificate.Subject, certificate.Thumbprint);
+        return certificate;
+    }
+}
+
+public interface IWebhookCertificateSource
+{
+    bool CanHandle(ZastavaWebhookTlsMode mode);
+
+    X509Certificate2 LoadCertificate(ZastavaWebhookTlsOptions options);
+}