using EntKube.Provisioning.Domain;
using FluentAssertions;

namespace EntKube.Provisioning.Tests.Domain;

public class PrometheusStackTests
{
    private readonly Guid clusterId = Guid.NewGuid();
    private readonly Guid environmentId = Guid.NewGuid();

    // ─── Creation ───────────────────────────────────────────────────────

    [Fact]
    public void Create_WithValidInputs_CreatesStackInPendingState()
    {
        // Arrange & Act — An operator provisions a new Prometheus stack on a cluster.
        // Prometheus is per-cluster: each cluster gets its own metrics collector.

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        // Assert — The stack should be in a Pending state, with sensible defaults
        // for Prometheus retention, replicas, and Alertmanager.

        stack.Id.Should().NotBe(Guid.Empty);
        stack.ClusterId.Should().Be(clusterId);
        stack.EnvironmentId.Should().Be(environmentId);
        stack.Name.Should().Be("prod-prometheus");
        stack.Namespace.Should().Be("monitoring");
        stack.Status.Should().Be(PrometheusStackStatus.Pending);
        stack.CreatedAt.Should().BeCloseTo(DateTimeOffset.UtcNow, TimeSpan.FromSeconds(5));

        // Prometheus defaults

        stack.Prometheus.Should().NotBeNull();
        stack.Prometheus.Retention.Should().Be("30d");
        stack.Prometheus.Replicas.Should().Be(2);
        stack.Prometheus.StorageSize.Should().Be("50Gi");

        // Alertmanager defaults

        stack.Alertmanager.Should().NotBeNull();
        stack.Alertmanager.Enabled.Should().BeTrue();
        stack.Alertmanager.Replicas.Should().Be(2);
    }

    [Fact]
    public void Create_WithEmptyName_ThrowsArgumentException()
    {
        // Arrange & Act — A Prometheus stack must have a name.

        Action act = () => PrometheusStack.Create(clusterId, environmentId, "", "monitoring");

        // Assert

        act.Should().Throw<ArgumentException>()
            .WithParameterName("name");
    }

    [Fact]
    public void Create_WithEmptyNamespace_ThrowsArgumentException()
    {
        // Arrange & Act — A Prometheus stack must have a namespace.

        Action act = () => PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "");

        // Assert

        act.Should().Throw<ArgumentException>()
            .WithParameterName("ns");
    }

    [Fact]
    public void Create_WithEmptyClusterId_ThrowsArgumentException()
    {
        // Arrange & Act — A Prometheus stack must belong to a cluster.

        Action act = () => PrometheusStack.Create(Guid.Empty, environmentId, "prod-prometheus", "monitoring");

        // Assert

        act.Should().Throw<ArgumentException>()
            .WithParameterName("clusterId");
    }

    [Fact]
    public void Create_WithEmptyEnvironmentId_ThrowsArgumentException()
    {
        // Arrange & Act — A Prometheus stack must belong to an environment.

        Action act = () => PrometheusStack.Create(clusterId, Guid.Empty, "prod-prometheus", "monitoring");

        // Assert

        act.Should().Throw<ArgumentException>()
            .WithParameterName("environmentId");
    }

    // ─── Prometheus Configuration ─────────────────────────────────────

    [Fact]
    public void ConfigurePrometheus_UpdatesRetentionAndReplicas()
    {
        // Arrange — Start with a Prometheus stack using defaults.

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        // Act — The operator increases retention to 90 days and scales to 3 replicas.

        stack.ConfigurePrometheus(retention: "90d", replicas: 3, storageSize: "100Gi", retentionSize: "90GB");

        // Assert — Prometheus settings should reflect the new configuration.

        stack.Prometheus.Retention.Should().Be("90d");
        stack.Prometheus.Replicas.Should().Be(3);
        stack.Prometheus.StorageSize.Should().Be("100Gi");
        stack.Prometheus.RetentionSize.Should().Be("90GB");
    }

    [Fact]
    public void ConfigurePrometheus_WithInvalidReplicas_ThrowsArgumentException()
    {
        // Arrange

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        // Act & Assert — Zero replicas doesn't make sense for Prometheus.

        Action act = () => stack.ConfigurePrometheus(replicas: 0);

        act.Should().Throw<ArgumentException>()
            .WithParameterName("replicas");
    }

    // ─── Alertmanager Configuration ─────────────────────────────────

    [Fact]
    public void ConfigureAlertmanager_UpdatesReplicasAndEnablement()
    {
        // Arrange

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        // Act — The operator disables Alertmanager for a dev cluster.

        stack.ConfigureAlertmanager(enabled: false, replicas: 1);

        // Assert

        stack.Alertmanager.Enabled.Should().BeFalse();
        stack.Alertmanager.Replicas.Should().Be(1);
    }

    // ─── Ingress (Prometheus + Alertmanager) ────────────────────────

    [Fact]
    public void ConfigureIngress_SetsPrometheusAndAlertmanagerRouting()
    {
        // Arrange — Publish Prometheus and Alertmanager via Gateway API.

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        // Act

        IngressConfiguration ingress = new(
            Enabled: true,
            Provider: IngressProvider.GatewayApi,
            PrometheusHostname: "prometheus.prod01.example.com",
            AlertmanagerHostname: "alertmanager.prod01.example.com",
            TlsEnabled: true,
            TlsCertificateMode: TlsCertificateMode.Manual,
            TlsSecretName: "monitoring-tls");

        stack.ConfigureIngress(ingress);

        // Assert

        stack.Ingress.Should().NotBeNull();
        stack.Ingress!.Enabled.Should().BeTrue();
        stack.Ingress.Provider.Should().Be(IngressProvider.GatewayApi);
        stack.Ingress.PrometheusHostname.Should().Be("prometheus.prod01.example.com");
        stack.Ingress.AlertmanagerHostname.Should().Be("alertmanager.prod01.example.com");
        stack.Ingress.TlsEnabled.Should().BeTrue();
        stack.Ingress.TlsCertificateMode.Should().Be(TlsCertificateMode.Manual);
        stack.Ingress.TlsSecretName.Should().Be("monitoring-tls");
    }

    [Fact]
    public void ConfigureIngress_WithCertManager_DoesNotRequireSecretName()
    {
        // Arrange

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        // Act — cert-manager with Let's Encrypt handles certificates automatically.

        IngressConfiguration ingress = new(
            Enabled: true,
            Provider: IngressProvider.GatewayApi,
            PrometheusHostname: "prometheus.example.com",
            AlertmanagerHostname: "alertmanager.example.com",
            TlsEnabled: true,
            TlsCertificateMode: TlsCertificateMode.CertManager,
            TlsSecretName: null,
            ClusterIssuer: "letsencrypt-prod");

        stack.ConfigureIngress(ingress);

        // Assert

        stack.Ingress!.TlsCertificateMode.Should().Be(TlsCertificateMode.CertManager);
        stack.Ingress.TlsSecretName.Should().BeNull();
        stack.Ingress.ClusterIssuer.Should().Be("letsencrypt-prod");
    }

    [Fact]
    public void DisableIngress_ClearsIngressConfig()
    {
        // Arrange

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        IngressConfiguration ingress = new(
            Enabled: true,
            Provider: IngressProvider.GatewayApi,
            PrometheusHostname: "prometheus.example.com",
            AlertmanagerHostname: null,
            TlsEnabled: true,
            TlsCertificateMode: TlsCertificateMode.Manual,
            TlsSecretName: "tls-secret");

        stack.ConfigureIngress(ingress);

        // Act

        stack.DisableIngress();

        // Assert

        stack.Ingress.Should().BeNull();
    }

    // ─── Lifecycle ──────────────────────────────────────────────────

    [Fact]
    public void MarkRunning_SetsStatusToRunning()
    {
        // Arrange

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        // Act

        stack.MarkRunning();

        // Assert

        stack.Status.Should().Be(PrometheusStackStatus.Running);
    }

    [Fact]
    public void MarkDegraded_SetsStatusToDegraded()
    {
        // Arrange

        PrometheusStack stack = PrometheusStack.Create(clusterId, environmentId, "prod-prometheus", "monitoring");

        // Act

        stack.MarkDegraded();

        // Assert

        stack.Status.Should().Be(PrometheusStackStatus.Degraded);
    }
}