package controller

import (
	"context"
	"fmt"

	"k8s.io/apimachinery/pkg/runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/log"

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

// BindCatalogZoneReconciler creates and maintains the catalog zone on a cluster
// primary so secondaries auto-provision member zones.
type BindCatalogZoneReconciler struct {
	client.Client
	Scheme *runtime.Scheme
	Exec   *bind.Executor
}

// +kubebuilder:rbac:groups=bind.unkin.net,resources=bindcatalogzones,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=bind.unkin.net,resources=bindcatalogzones/status,verbs=get;update;patch
// +kubebuilder:rbac:groups=bind.unkin.net,resources=bindzones;bindtsigkeys,verbs=get;list;watch

func (r *BindCatalogZoneReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	logger := log.FromContext(ctx)

	var catalog bindv1alpha1.BindCatalogZone
	if err := r.Get(ctx, req.NamespacedName, &catalog); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	cluster, err := getCluster(ctx, r.Client, catalog.Namespace, catalog.Spec.ClusterRef)
	if err != nil {
		return r.fail(ctx, &catalog, "ClusterMissing", err.Error())
	}
	primaryPod := primaryPodName(cluster.Name)

	if !primaryReady(ctx, r.Client, cluster) || r.Exec == nil {
		return r.fail(ctx, &catalog, "PrimaryNotReady", "waiting for cluster primary")
	}

	creds, err := resolveTSIG(ctx, r.Client, catalog.Namespace, catalog.Spec.TransferKeyRef)
	if err != nil {
		return r.fail(ctx, &catalog, "NoTransferKey", err.Error())
	}

	// Ensure the catalog zone exists on the primary.
	if !r.Exec.ZoneExists(ctx, catalog.Namespace, primaryPod, catalog.Spec.ZoneName, "") {
		if err := r.Exec.WriteSeedZone(ctx, catalog.Namespace, primaryPod, catalog.Spec.ZoneName, bind.CatalogFilePath(catalog.Spec.ZoneName), "", 1); err != nil {
			return r.fail(ctx, &catalog, "SeedFailed", err.Error())
		}
	}
	zoneConfig := fmt.Sprintf("{ type primary; file \"%s\"; allow-transfer { key \"%s\"; }; allow-update { key \"%s\"; }; };",
		bind.CatalogFilePath(catalog.Spec.ZoneName), catalog.Spec.TransferKeyRef, catalog.Spec.TransferKeyRef)
	if err := r.Exec.AddZone(ctx, catalog.Namespace, primaryPod, catalog.Spec.ZoneName, "", zoneConfig); err != nil {
		return r.fail(ctx, &catalog, "AddZoneFailed", err.Error())
	}

	// Catalog zones must advertise their schema version (RFC 9432: "2").
	versionUpdate := bind.RecordUpdate{
		FQDN:   "version." + catalog.Spec.ZoneName + ".",
		Type:   "TXT",
		TTL:    3600,
		Values: []string{"\"2\""},
	}
	if err := r.Exec.NSUpdate(ctx, catalog.Namespace, primaryPod, catalog.Spec.ZoneName, creds, []bind.RecordUpdate{versionUpdate}); err != nil {
		return r.fail(ctx, &catalog, "VersionUpdateFailed", err.Error())
	}

	// Count member zones for status.
	var zones bindv1alpha1.BindZoneList
	members := int32(0)
	if err := r.List(ctx, &zones, client.InNamespace(catalog.Namespace)); err == nil {
		for i := range zones.Items {
			z := &zones.Items[i]
			if z.Spec.ClusterRef == cluster.Name && catalogEnabled(z) {
				members++
			}
		}
	}

	catalog.Status.Ready = true
	catalog.Status.MemberCount = members
	catalog.Status.ObservedGeneration = catalog.Generation
	setReady(&catalog.Status.Conditions, catalog.Generation, true, "Ready", "catalog zone provisioned")
	if err := r.Status().Update(ctx, &catalog); err != nil {
		return ctrl.Result{}, err
	}
	logger.Info("catalog zone reconciled", "zone", catalog.Spec.ZoneName, "members", members)
	return ctrl.Result{RequeueAfter: requeueLong}, nil
}

func (r *BindCatalogZoneReconciler) fail(ctx context.Context, catalog *bindv1alpha1.BindCatalogZone, reason, msg string) (ctrl.Result, error) {
	catalog.Status.Ready = false
	catalog.Status.ObservedGeneration = catalog.Generation
	setReady(&catalog.Status.Conditions, catalog.Generation, false, reason, msg)
	if err := r.Status().Update(ctx, catalog); err != nil {
		return ctrl.Result{}, err
	}
	return ctrl.Result{RequeueAfter: requeueShort}, nil
}

func (r *BindCatalogZoneReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&bindv1alpha1.BindCatalogZone{}).
		Complete(r)
}