package controller

import (
	"context"
	"strings"
	"testing"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/client/fake"

	bindv1alpha1 "git.unkin.net/unkin/bind-operator/api/v1alpha1"
)

// TestConfigHashIndependentOfPrimaryPodIP is the permanent regression guard for
// the v0.2.5 rolling-restart loop.
//
// v0.2.5 rendered an options-scope `allow-notify { <primaryPodIP>; ... }` into
// the (restart-scoped) named.conf. The config-hash annotation that rolls the
// StatefulSet is computed over that render (BindClusterReconciler.configHash), so
// a config change rolled the pods, the primary pod came back on a NEW IP, the
// operator re-rendered with the new IP, the hash changed, the pods rolled again,
// and so on — an infinite roll loop across every BindCluster.
//
// The fix removed all pod IPs from restart-scoped config (secondaries now admit
// intra-cluster NOTIFYs by TSIG key: `allow-notify { key "X"; }`). This test
// reconciles the ConfigMap with the primary pod on one IP, computes the hash,
// then does it again with the primary pod on a DIFFERENT IP, and asserts the
// hash is byte-identical. If any pod-IP dependency ever creeps back into
// restart-scoped config, this fails and the loop-class bug is caught.
func TestConfigHashIndependentOfPrimaryPodIP(t *testing.T) {
	scheme := runtime.NewScheme()
	if err := clientgoscheme.AddToScheme(scheme); err != nil {
		t.Fatal(err)
	}
	if err := bindv1alpha1.AddToScheme(scheme); err != nil {
		t.Fatal(err)
	}

	const ns = "dns"
	svcIP := "10.43.5.5" // stable primary Service ClusterIP (does NOT churn)

	cluster := &bindv1alpha1.BindCluster{
		ObjectMeta: metav1.ObjectMeta{Name: "auth", Namespace: ns},
		Spec: bindv1alpha1.BindClusterSpec{
			Mode:           bindv1alpha1.ModeAuthoritative,
			Replicas:       3,
			PrimaryService: &bindv1alpha1.ClusterServiceSpec{},
		},
	}
	primarySvc := &corev1.Service{
		ObjectMeta: metav1.ObjectMeta{Name: primaryServiceName(cluster.Name), Namespace: ns},
		Spec:       corev1.ServiceSpec{ClusterIP: svcIP},
	}
	catalog := &bindv1alpha1.BindCatalogZone{
		ObjectMeta: metav1.ObjectMeta{Name: "cat", Namespace: ns},
		Spec: bindv1alpha1.BindCatalogZoneSpec{
			ClusterRef:     cluster.Name,
			ZoneName:       "catalog.internal",
			TransferKeyRef: "externaldns-key",
		},
	}
	tsig := &bindv1alpha1.BindTSIGKey{
		ObjectMeta: metav1.ObjectMeta{Name: "externaldns-key", Namespace: ns},
		Spec:       bindv1alpha1.BindTSIGKeySpec{ClusterRef: cluster.Name},
	}

	// hashWithPrimaryIP reconciles the ConfigMap with the primary pod carrying the
	// given IP, then returns the resulting config-hash.
	hashWithPrimaryIP := func(ip string) string {
		primaryPod := &corev1.Pod{
			ObjectMeta: metav1.ObjectMeta{Name: primaryPodName(cluster.Name), Namespace: ns, Labels: commonLabels(cluster.Name)},
			Status:     corev1.PodStatus{PodIP: ip},
		}
		c := fake.NewClientBuilder().
			WithScheme(scheme).
			WithObjects(cluster, primarySvc, catalog, tsig, primaryPod).
			Build()
		r := &BindClusterReconciler{Client: c, Scheme: scheme}
		ctx := context.Background()
		if err := r.reconcileConfigMap(ctx, cluster); err != nil {
			t.Fatalf("reconcileConfigMap: %v", err)
		}
		// Sanity: the pod IP must not have leaked into the rendered config.
		var cm corev1.ConfigMap
		if err := c.Get(ctx, client.ObjectKey{Namespace: ns, Name: configMapName(cluster.Name)}, &cm); err != nil {
			t.Fatalf("get configmap: %v", err)
		}
		for k, v := range cm.Data {
			if ip != "" && strings.Contains(v, ip) {
				t.Fatalf("primary pod IP %s leaked into restart-scoped config %s:\n%s", ip, k, v)
			}
		}
		return r.configHash(ctx, cluster)
	}

	h1 := hashWithPrimaryIP("10.42.3.197")
	h2 := hashWithPrimaryIP("10.42.9.42") // primary pod restarted onto a new IP
	if h1 == "" {
		t.Fatal("config hash should not be empty")
	}
	if h1 != h2 {
		t.Fatalf("config hash changed when only the primary pod IP changed — the v0.2.5 roll loop:\n%s\n%s", h1, h2)
	}
}