package webhookconfig

import (
	"context"
	"encoding/json"
	"fmt"
	"reflect"
	"strings"
	"sync/atomic"
	"time"

	"github.com/go-logr/logr"
	kyverno "github.com/kyverno/kyverno/api/kyverno/v1"
	"github.com/kyverno/kyverno/pkg/autogen"
	kyvernoclient "github.com/kyverno/kyverno/pkg/client/clientset/versioned"
	kyvernoinformer "github.com/kyverno/kyverno/pkg/client/informers/externalversions/kyverno/v1"
	kyvernolister "github.com/kyverno/kyverno/pkg/client/listers/kyverno/v1"
	"github.com/kyverno/kyverno/pkg/common"
	"github.com/kyverno/kyverno/pkg/config"
	client "github.com/kyverno/kyverno/pkg/dclient"
	"github.com/kyverno/kyverno/pkg/resourcecache"
	"github.com/kyverno/kyverno/pkg/utils"
	"github.com/pkg/errors"
	admregapi "k8s.io/api/admissionregistration/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime/schema"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	adminformers "k8s.io/client-go/informers/admissionregistration/v1"
	informers "k8s.io/client-go/informers/core/v1"
	admlisters "k8s.io/client-go/listers/admissionregistration/v1"
	listers "k8s.io/client-go/listers/core/v1"
	"k8s.io/client-go/tools/cache"
	"k8s.io/client-go/util/workqueue"
)

var DefaultWebhookTimeout int64 = 10

// webhookConfigManager manges the webhook configuration dynamically
// it is NOT multi-thread safe
type webhookConfigManager struct {
	client        *client.Client
	kyvernoClient *kyvernoclient.Clientset

	pInformer  kyvernoinformer.ClusterPolicyInformer
	npInformer kyvernoinformer.PolicyInformer

	// pLister can list/get policy from the shared informer's store
	pLister kyvernolister.ClusterPolicyLister

	// npLister can list/get namespace policy from the shared informer's store
	npLister kyvernolister.PolicyLister

	// pListerSynced returns true if the cluster policy store has been synced at least once
	pListerSynced cache.InformerSynced

	// npListerSynced returns true if the namespace policy store has been synced at least once
	npListerSynced cache.InformerSynced

	resCache resourcecache.ResourceCache

	mutateInformer         cache.SharedIndexInformer
	validateInformer       cache.SharedIndexInformer
	mutateLister           admlisters.MutatingWebhookConfigurationLister
	validateLister         admlisters.ValidatingWebhookConfigurationLister
	mutateInformerSynced   cache.InformerSynced
	validateInformerSynced cache.InformerSynced

	queue workqueue.RateLimitingInterface

	// serverIP used to get the name of debug webhooks
	serverIP string

	autoUpdateWebhooks bool

	// wildcardPolicy indicates the number of policies that matches all kinds (*) defined
	wildcardPolicy int64

	createDefaultWebhook chan<- string

	stopCh <-chan struct{}

	log logr.Logger

	nsLister       listers.NamespaceLister
	nsListerSynced func() bool
}

type manage interface {
	start()
}

func newWebhookConfigManager(
	client *client.Client,
	kyvernoClient *kyvernoclient.Clientset,
	pInformer kyvernoinformer.ClusterPolicyInformer,
	npInformer kyvernoinformer.PolicyInformer,
	mwcInformer adminformers.MutatingWebhookConfigurationInformer,
	vwcInformer adminformers.ValidatingWebhookConfigurationInformer,
	resCache resourcecache.ResourceCache,
	nsInformer informers.NamespaceInformer,
	serverIP string,
	autoUpdateWebhooks bool,
	createDefaultWebhook chan<- string,
	stopCh <-chan struct{},
	log logr.Logger) manage {

	m := &webhookConfigManager{
		client:               client,
		kyvernoClient:        kyvernoClient,
		pInformer:            pInformer,
		npInformer:           npInformer,
		resCache:             resCache,
		queue:                workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "configmanager"),
		wildcardPolicy:       0,
		serverIP:             serverIP,
		autoUpdateWebhooks:   autoUpdateWebhooks,
		createDefaultWebhook: createDefaultWebhook,
		stopCh:               stopCh,
		log:                  log,
	}

	m.pLister = pInformer.Lister()
	m.npLister = npInformer.Lister()

	m.nsLister = nsInformer.Lister()
	m.nsListerSynced = nsInformer.Informer().HasSynced

	m.pListerSynced = pInformer.Informer().HasSynced
	m.npListerSynced = npInformer.Informer().HasSynced

	m.mutateInformer = mwcInformer.Informer()
	m.mutateLister = mwcInformer.Lister()
	m.mutateInformerSynced = mwcInformer.Informer().HasSynced

	m.validateInformer = vwcInformer.Informer()
	m.validateLister = vwcInformer.Lister()
	m.validateInformerSynced = vwcInformer.Informer().HasSynced

	return m
}

func (m *webhookConfigManager) handleErr(err error, key interface{}) {
	logger := m.log
	if err == nil {
		m.queue.Forget(key)
		return
	}

	if m.queue.NumRequeues(key) < 3 {
		logger.Error(err, "failed to sync policy", "key", key)
		m.queue.AddRateLimited(key)
		return
	}

	utilruntime.HandleError(err)
	logger.V(2).Info("dropping policy out of queue", "key", key)
	m.queue.Forget(key)
}

func (m *webhookConfigManager) addClusterPolicy(obj interface{}) {
	p := obj.(*kyverno.ClusterPolicy)
	if hasWildcard(p) {
		atomic.AddInt64(&m.wildcardPolicy, int64(1))
	}
	m.enqueue(p)
}

func (m *webhookConfigManager) updateClusterPolicy(old, cur interface{}) {
	oldP := old.(*kyverno.ClusterPolicy)
	curP := cur.(*kyverno.ClusterPolicy)

	if reflect.DeepEqual(oldP.Spec, curP.Spec) {
		return
	}

	if hasWildcard(oldP) && !hasWildcard(curP) {
		atomic.AddInt64(&m.wildcardPolicy, ^int64(0))
	} else if !hasWildcard(oldP) && hasWildcard(curP) {
		atomic.AddInt64(&m.wildcardPolicy, int64(1))
	}

	m.enqueue(curP)
}

func (m *webhookConfigManager) deleteClusterPolicy(obj interface{}) {
	p, ok := obj.(*kyverno.ClusterPolicy)
	if !ok {
		tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
		if !ok {
			utilruntime.HandleError(fmt.Errorf("error decoding object, invalid type"))
			return
		}
		p, ok = tombstone.Obj.(*kyverno.ClusterPolicy)
		if !ok {
			utilruntime.HandleError(fmt.Errorf("error decoding object tombstone, invalid type"))
			return
		}
		m.log.V(4).Info("Recovered deleted ClusterPolicy '%s' from tombstone", "name", p.GetName())
	}

	if hasWildcard(p) {
		atomic.AddInt64(&m.wildcardPolicy, ^int64(0))
	}
	m.enqueue(p)
}

func (m *webhookConfigManager) addPolicy(obj interface{}) {
	p := obj.(*kyverno.Policy)
	if hasWildcard(p) {
		atomic.AddInt64(&m.wildcardPolicy, int64(1))
	}

	pol := kyverno.ClusterPolicy(*p)
	m.enqueue(&pol)
}

func (m *webhookConfigManager) updatePolicy(old, cur interface{}) {
	oldP := old.(*kyverno.Policy)
	curP := cur.(*kyverno.Policy)

	if reflect.DeepEqual(oldP.Spec, curP.Spec) {
		return
	}

	if hasWildcard(oldP) && !hasWildcard(curP) {
		atomic.AddInt64(&m.wildcardPolicy, ^int64(0))
	} else if !hasWildcard(oldP) && hasWildcard(curP) {
		atomic.AddInt64(&m.wildcardPolicy, int64(1))
	}

	pol := kyverno.ClusterPolicy(*curP)
	m.enqueue(&pol)
}

func (m *webhookConfigManager) deletePolicy(obj interface{}) {
	p, ok := obj.(*kyverno.Policy)
	if !ok {
		tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
		if !ok {
			utilruntime.HandleError(fmt.Errorf("error decoding object, invalid type"))
			return
		}
		p, ok = tombstone.Obj.(*kyverno.Policy)
		if !ok {
			utilruntime.HandleError(fmt.Errorf("error decoding object tombstone, invalid type"))
			return
		}
		m.log.V(4).Info("Recovered deleted ClusterPolicy '%s' from tombstone", "name", p.GetName())
	}

	if hasWildcard(p) {
		atomic.AddInt64(&m.wildcardPolicy, ^int64(0))
	}

	pol := kyverno.ClusterPolicy(*p)
	m.enqueue(&pol)
}

func (m *webhookConfigManager) deleteWebhook(obj interface{}) {
	m.log.WithName("deleteWebhook").Info("resource webhook configuration was deleted, recreating...")
	if webhook, ok := obj.(*unstructured.Unstructured); ok {
		k := webhook.GetKind()
		if (k == kindMutating && webhook.GetName() == config.MutatingWebhookConfigurationName) ||
			(k == kindValidating && webhook.GetName() == config.ValidatingWebhookConfigurationName) {
			m.enqueueAllPolicies()
		}
	}
}

func (m *webhookConfigManager) enqueueAllPolicies() {
	logger := m.log.WithName("enqueueAllPolicies")

	policies, err := m.listAllPolicies()
	if err != nil {
		logger.Error(err, "unabled to list policies")
	}

	for _, policy := range policies {
		m.enqueue(policy)
		logger.V(4).Info("added policy to the queue", "namespace", policy.GetNamespace(), "name", policy.GetName())
	}
}

func (m *webhookConfigManager) enqueue(policy *kyverno.ClusterPolicy) {
	logger := m.log
	key, err := cache.MetaNamespaceKeyFunc(policy)
	if err != nil {
		logger.Error(err, "failed to enqueue policy")
		return
	}
	m.queue.Add(key)
}

// start is a blocking call to configure webhook
func (m *webhookConfigManager) start() {
	defer utilruntime.HandleCrash()
	defer m.queue.ShutDown()

	m.log.Info("starting")
	defer m.log.Info("shutting down")

	if !cache.WaitForCacheSync(m.stopCh, m.pListerSynced, m.npListerSynced, m.mutateInformerSynced, m.validateInformerSynced, m.nsListerSynced) {
		m.log.Info("failed to sync informer cache")
		return
	}

	m.pInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
		AddFunc:    m.addClusterPolicy,
		UpdateFunc: m.updateClusterPolicy,
		DeleteFunc: m.deleteClusterPolicy,
	})

	m.npInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
		AddFunc:    m.addPolicy,
		UpdateFunc: m.updatePolicy,
		DeleteFunc: m.deletePolicy,
	})

	m.mutateInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
		DeleteFunc: m.deleteWebhook,
	})

	m.validateInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
		DeleteFunc: m.deleteWebhook,
	})

	for m.processNextWorkItem() {
	}
}

func (m *webhookConfigManager) processNextWorkItem() bool {
	key, quit := m.queue.Get()
	if quit {
		return false
	}
	defer m.queue.Done(key)
	err := m.sync(key.(string))
	m.handleErr(err, key)

	return true
}

func (m *webhookConfigManager) sync(key string) error {
	logger := m.log.WithName("sync")
	startTime := time.Now()
	logger.V(4).Info("started syncing policy", "key", key, "startTime", startTime)
	defer func() {
		logger.V(4).Info("finished syncing policy", "key", key, "processingTime", time.Since(startTime).String())
	}()

	namespace, name, err := cache.SplitMetaNamespaceKey(key)
	if err != nil {
		logger.Info("invalid resource key", "key", key)
		return nil
	}

	return m.reconcileWebhook(namespace, name)
}

func (m *webhookConfigManager) reconcileWebhook(namespace, name string) error {
	logger := m.log.WithName("reconcileWebhook").WithValues("namespace", namespace, "policy", name)

	policy, err := m.getPolicy(namespace, name)
	if err != nil && !apierrors.IsNotFound(err) {
		return errors.Wrapf(err, "unable to get policy object %s/%s", namespace, name)
	}

	ready := true
	// build webhook only if auto-update is enabled, otherwise directly update status to ready
	if m.autoUpdateWebhooks {
		webhooks, err := m.buildWebhooks(namespace)
		if err != nil {
			return err
		}

		if err := m.updateWebhookConfig(webhooks); err != nil {
			ready = false
			logger.Error(err, "failed to update webhook configurations for policy")
		}

		// DELETION of the policy
		if policy == nil {
			return nil
		}
	}

	if err := m.updateStatus(policy, ready); err != nil {
		return errors.Wrapf(err, "failed to update policy status %s/%s", namespace, name)
	}

	if ready {
		logger.Info("policy is ready to serve admission requests")
	}
	return nil
}

func (m *webhookConfigManager) getPolicy(namespace, name string) (*kyverno.ClusterPolicy, error) {
	if namespace == "" {
		return m.pLister.Get(name)
	}

	nsPolicy, err := m.npLister.Policies(namespace).Get(name)
	if err == nil && nsPolicy != nil {
		p := kyverno.ClusterPolicy(*nsPolicy)
		return &p, err
	}

	return nil, err
}

func (m *webhookConfigManager) listAllPolicies() ([]*kyverno.ClusterPolicy, error) {
	policies := []*kyverno.ClusterPolicy{}

	namespaces, err := m.nsLister.List(labels.Everything())
	if err != nil {
		m.log.Error(err, "unabled to list namespaces")
		return nil, err
	}

	for _, ns := range namespaces {
		polList, err := m.npLister.Policies(ns.GetName()).List(labels.Everything())
		if err != nil {
			return nil, errors.Wrapf(err, "failed to list Policy")
		}

		for _, pol := range polList {
			p := kyverno.ClusterPolicy(*pol)
			policies = append(policies, &p)
		}
	}

	cpolList, err := m.pLister.List(labels.Everything())
	if err != nil {
		return nil, errors.Wrapf(err, "failed to list ClusterPolicy")
	}

	policies = append(policies, cpolList...)
	return policies, nil
}

const (
	apiGroups   string = "apiGroups"
	apiVersions string = "apiVersions"
	resources   string = "resources"
)

// webhook is the instance that aggregates the GVK of existing policies
// based on kind, failurePolicy and webhookTimeout
type webhook struct {
	kind              string
	maxWebhookTimeout int64
	failurePolicy     kyverno.FailurePolicyType

	// rule represents the same rule struct of the webhook using a map object
	// https://github.com/kubernetes/api/blob/master/admissionregistration/v1/types.go#L25
	rule map[string]interface{}
}

func (m *webhookConfigManager) buildWebhooks(namespace string) (res []*webhook, err error) {
	mutateIgnore := newWebhook(kindMutating, DefaultWebhookTimeout, kyverno.Ignore)
	mutateFail := newWebhook(kindMutating, DefaultWebhookTimeout, kyverno.Fail)
	validateIgnore := newWebhook(kindValidating, DefaultWebhookTimeout, kyverno.Ignore)
	validateFail := newWebhook(kindValidating, DefaultWebhookTimeout, kyverno.Fail)

	if atomic.LoadInt64(&m.wildcardPolicy) != 0 {
		for _, w := range []*webhook{mutateIgnore, mutateFail, validateIgnore, validateFail} {
			setWildcardConfig(w)
		}

		m.log.V(4).WithName("buildWebhooks").Info("warning: found wildcard policy, setting webhook configurations to accept admission requests of all kinds")
		return append(res, mutateIgnore, mutateFail, validateIgnore, validateFail), nil
	}

	policies, err := m.listAllPolicies()
	if err != nil {
		return nil, errors.Wrap(err, "unable to list current policies")
	}

	for _, p := range policies {
		if p.HasValidate() || p.HasGenerate() {
			if p.Spec.FailurePolicy != nil && *p.Spec.FailurePolicy == kyverno.Ignore {
				m.mergeWebhook(validateIgnore, p, true)
			} else {
				m.mergeWebhook(validateFail, p, true)
			}
		}

		if p.HasMutate() || p.HasVerifyImages() {
			if p.Spec.FailurePolicy != nil && *p.Spec.FailurePolicy == kyverno.Ignore {
				m.mergeWebhook(mutateIgnore, p, false)
			} else {
				m.mergeWebhook(mutateFail, p, false)
			}
		}
	}

	res = append(res, mutateIgnore, mutateFail, validateIgnore, validateFail)
	return res, nil
}

func (m *webhookConfigManager) updateWebhookConfig(webhooks []*webhook) error {
	logger := m.log.WithName("updateWebhookConfig")

	webhooksMap := make(map[string]interface{}, len(webhooks))
	for _, w := range webhooks {
		key := webhookKey(w.kind, string(w.failurePolicy))
		webhooksMap[key] = w
	}

	var errs []string
	if err := m.compareAndUpdateWebhook(kindMutating, getResourceMutatingWebhookConfigName(m.serverIP), webhooksMap); err != nil {
		logger.V(4).Info("failed to update mutatingwebhookconfigurations", "error", err.Error())
		errs = append(errs, err.Error())
	}

	if err := m.compareAndUpdateWebhook(kindValidating, getResourceValidatingWebhookConfigName(m.serverIP), webhooksMap); err != nil {
		logger.V(4).Info("failed to update validatingwebhookconfigurations", "error", err.Error())
		errs = append(errs, err.Error())
	}

	if len(errs) != 0 {
		return errors.New(strings.Join(errs, "\n"))
	}

	return nil
}

func (m *webhookConfigManager) getWebhook(webhookKind, webhookName string) (resourceWebhook *unstructured.Unstructured, err error) {
	get := func() error {
		resourceWebhook = &unstructured.Unstructured{}
		err = nil

		var rawResc []byte

		switch webhookKind {
		case kindMutating:
			resourceWebhookTyped, err := m.mutateLister.Get(webhookName)
			if err != nil && !apierrors.IsNotFound(err) {
				return errors.Wrapf(err, "unable to get %s/%s", webhookKind, webhookName)
			} else if apierrors.IsNotFound(err) {
				m.createDefaultWebhook <- webhookKind
				return err
			}
			resourceWebhookTyped.SetGroupVersionKind(schema.GroupVersionKind{Group: "", Version: "admissionregistration.k8s.io/v1", Kind: kindMutating})
			rawResc, err = json.Marshal(resourceWebhookTyped)
			if err != nil {
				return err
			}
		case kindValidating:
			resourceWebhookTyped, err := m.validateLister.Get(webhookName)
			if err != nil && !apierrors.IsNotFound(err) {
				return errors.Wrapf(err, "unable to get %s/%s", webhookKind, webhookName)
			} else if apierrors.IsNotFound(err) {
				m.createDefaultWebhook <- webhookKind
				return err
			}
			resourceWebhookTyped.SetGroupVersionKind(schema.GroupVersionKind{Group: "", Version: "admissionregistration.k8s.io/v1", Kind: kindValidating})
			rawResc, err = json.Marshal(resourceWebhookTyped)
			if err != nil {
				return err
			}
		default:
			return fmt.Errorf("unknown webhook kind: must be '%v' or '%v'", kindMutating, kindValidating)
		}

		err = json.Unmarshal(rawResc, &resourceWebhook.Object)

		return err
	}

	retryGetWebhook := common.RetryFunc(time.Second, 10*time.Second, get, m.log)
	if err := retryGetWebhook(); err != nil {
		return nil, err
	}

	return resourceWebhook, nil
}

// webhookRulesEqual compares webhook rules between
// the representation returned by the API server,
// and the internal representation that is generated.
//
// The two representations are slightly different,
// so this function handles those differences.
func webhookRulesEqual(apiRules []interface{}, internalRules []interface{}) (bool, error) {
	// Handle edge case when both are empty.
	// API representation is a nil slice,
	// internal representation is one rule
	// but with no selectors.
	if len(apiRules) == 0 && len(internalRules) == 1 {
		if len(internalRules[0].(map[string]interface{})) == 0 {
			return true, nil
		}
	}

	// Both *should* be length 1, but as long
	// as they are equal the next loop works.
	if len(apiRules) != len(internalRules) {
		return false, nil
	}

	for i := range internalRules {
		internal, ok := internalRules[i].(map[string]interface{})
		if !ok {
			return false, errors.New("type conversion of internal rules failed")
		}
		api, ok := apiRules[i].(map[string]interface{})
		if !ok {
			return false, errors.New("type conversion of API rules failed")
		}

		// Range over the fields of internal, as the
		// API rule has extra fields (operations, scope)
		// that can't be checked on the internal rules.
		for field := range internal {
			// Convert the API rules values to []string.
			apiValues, _, err := unstructured.NestedStringSlice(api, field)
			if err != nil {
				return false, errors.Wrapf(err, "error getting string slice for API rules field %s", field)
			}

			// Internal type is already []string.
			internalValues := internal[field]

			if !reflect.DeepEqual(internalValues, apiValues) {
				return false, nil
			}
		}
	}

	return true, nil
}

func (m *webhookConfigManager) compareAndUpdateWebhook(webhookKind, webhookName string, webhooksMap map[string]interface{}) error {
	logger := m.log.WithName("compareAndUpdateWebhook").WithValues("kind", webhookKind, "name", webhookName)
	resourceWebhook, err := m.getWebhook(webhookKind, webhookName)
	if err != nil {
		return err
	}

	webhooksUntyped, _, err := unstructured.NestedSlice(resourceWebhook.UnstructuredContent(), "webhooks")
	if err != nil {
		return errors.Wrapf(err, "unable to fetch tag webhooks for %s/%s", webhookKind, webhookName)
	}

	newWebooks := make([]interface{}, len(webhooksUntyped))
	copy(newWebooks, webhooksUntyped)
	var changed bool
	for i, webhookUntyed := range webhooksUntyped {
		existingWebhook, ok := webhookUntyed.(map[string]interface{})
		if !ok {
			logger.Error(errors.New("type mismatched"), "expected map[string]interface{}, got %T", webhooksUntyped)
			continue
		}

		failurePolicy, _, err := unstructured.NestedString(existingWebhook, "failurePolicy")
		if err != nil {
			logger.Error(errors.New("type mismatched"), "expected string, got %T", failurePolicy)
			continue

		}

		rules, _, err := unstructured.NestedSlice(existingWebhook, "rules")
		if err != nil {
			logger.Error(err, "type mismatched, expected []interface{}, got %T", rules)
			continue
		}

		newWebhook := webhooksMap[webhookKey(webhookKind, failurePolicy)]
		w, ok := newWebhook.(*webhook)
		if !ok {
			logger.Error(errors.New("type mismatched"), "expected *webhook, got %T", newWebooks)
			continue
		}

		rulesEqual, err := webhookRulesEqual(rules, []interface{}{w.rule})
		if err != nil {
			logger.Error(err, "failed to compare webhook rules")
			continue
		}

		if !rulesEqual {
			changed = true

			tmpRules, ok := newWebooks[i].(map[string]interface{})["rules"].([]interface{})
			if !ok {
				// init operations
				ops := []string{string(admregapi.Create), string(admregapi.Update), string(admregapi.Delete), string(admregapi.Connect)}
				if webhookKind == kindMutating {
					ops = []string{string(admregapi.Create), string(admregapi.Update), string(admregapi.Delete)}
				}

				tmpRules = []interface{}{map[string]interface{}{}}
				if err = unstructured.SetNestedStringSlice(tmpRules[0].(map[string]interface{}), ops, "operations"); err != nil {
					return errors.Wrapf(err, "unable to set webhooks[%d].rules[0].%s", i, apiGroups)
				}
			}

			if w.rule == nil || reflect.DeepEqual(w.rule, map[string]interface{}{}) {
				// zero kyverno policy with the current failurePolicy, reset webhook rules to empty
				newWebooks[i].(map[string]interface{})["rules"] = []interface{}{}
				continue
			}

			if err = unstructured.SetNestedStringSlice(tmpRules[0].(map[string]interface{}), w.rule[apiGroups].([]string), apiGroups); err != nil {
				return errors.Wrapf(err, "unable to set webhooks[%d].rules[0].%s", i, apiGroups)
			}
			if err = unstructured.SetNestedStringSlice(tmpRules[0].(map[string]interface{}), w.rule[apiVersions].([]string), apiVersions); err != nil {
				return errors.Wrapf(err, "unable to set webhooks[%d].rules[0].%s", i, apiVersions)
			}
			if err = unstructured.SetNestedStringSlice(tmpRules[0].(map[string]interface{}), w.rule[resources].([]string), resources); err != nil {
				return errors.Wrapf(err, "unable to set webhooks[%d].rules[0].%s", i, resources)
			}

			newWebooks[i].(map[string]interface{})["rules"] = tmpRules
		}

		if err = unstructured.SetNestedField(newWebooks[i].(map[string]interface{}), w.maxWebhookTimeout, "timeoutSeconds"); err != nil {
			return errors.Wrapf(err, "unable to set webhooks[%d].timeoutSeconds to %v", i, w.maxWebhookTimeout)
		}
	}

	if changed {
		logger.V(4).Info("webhook configuration has been changed, updating")
		if err := unstructured.SetNestedSlice(resourceWebhook.UnstructuredContent(), newWebooks, "webhooks"); err != nil {
			return errors.Wrap(err, "unable to set new webhooks")
		}

		if _, err := m.client.UpdateResource(resourceWebhook.GetAPIVersion(), resourceWebhook.GetKind(), "", resourceWebhook, false); err != nil {
			return errors.Wrapf(err, "unable to update %s/%s: %s", resourceWebhook.GetAPIVersion(), resourceWebhook.GetKind(), resourceWebhook.GetName())
		}

		logger.V(4).Info("successfully updated the webhook configuration")
	}

	return nil
}

func (m *webhookConfigManager) updateStatus(policy *kyverno.ClusterPolicy, status bool) error {
	policyCopy := policy.DeepCopy()
	requested, supported, activated := autogen.GetControllers(policy.ObjectMeta, &policy.Spec, m.log)
	policyCopy.Status.SetReady(status)
	policyCopy.Status.Autogen.Requested = requested
	policyCopy.Status.Autogen.Supported = supported
	policyCopy.Status.Autogen.Activated = activated
	policyCopy.Status.Rules = policy.Spec.Rules
	if reflect.DeepEqual(policyCopy.Status, policy.Status) {
		return nil
	}
	if policy.GetNamespace() == "" {
		_, err := m.kyvernoClient.KyvernoV1().ClusterPolicies().UpdateStatus(context.TODO(), policyCopy, v1.UpdateOptions{})
		return err
	}
	_, err := m.kyvernoClient.KyvernoV1().Policies(policyCopy.GetNamespace()).UpdateStatus(context.TODO(), (*kyverno.Policy)(policyCopy), v1.UpdateOptions{})
	return err
}

// mergeWebhook merges the matching kinds of the policy to webhook.rule
func (m *webhookConfigManager) mergeWebhook(dst *webhook, policy *kyverno.ClusterPolicy, updateValidate bool) {
	matchedGVK := make([]string, 0)
	for _, rule := range policy.GetRules() {
		// matching kinds in generate policies need to be added to both webhook
		if rule.HasGenerate() {
			matchedGVK = append(matchedGVK, rule.MatchKinds()...)
			matchedGVK = append(matchedGVK, rule.Generation.ResourceSpec.Kind)
			continue
		}

		if (updateValidate && rule.HasValidate()) ||
			(!updateValidate && rule.HasMutate()) ||
			(!updateValidate && rule.HasVerifyImages()) {
			matchedGVK = append(matchedGVK, rule.MatchKinds()...)
		}
	}

	gvkMap := make(map[string]int)
	gvrList := make([]schema.GroupVersionResource, 0)
	for _, gvk := range matchedGVK {
		if _, ok := gvkMap[gvk]; !ok {
			gvkMap[gvk] = 1

			// note: webhook stores GVR in its rules while policy stores GVK in its rules definition
			gv, k := common.GetKindFromGVK(gvk)
			switch k {
			case "Binding":
				gvrList = append(gvrList, schema.GroupVersionResource{Group: "", Version: "v1", Resource: "pods/binding"})
			case "NodeProxyOptions":
				gvrList = append(gvrList, schema.GroupVersionResource{Group: "", Version: "v1", Resource: "nodes/proxy"})
			case "PodAttachOptions":
				gvrList = append(gvrList, schema.GroupVersionResource{Group: "", Version: "v1", Resource: "pods/attach"})
			case "PodExecOptions":
				gvrList = append(gvrList, schema.GroupVersionResource{Group: "", Version: "v1", Resource: "pods/exec"})
			case "PodPortForwardOptions":
				gvrList = append(gvrList, schema.GroupVersionResource{Group: "", Version: "v1", Resource: "pods/portforward"})
			case "PodProxyOptions":
				gvrList = append(gvrList, schema.GroupVersionResource{Group: "", Version: "v1", Resource: "pods/proxy"})
			case "ServiceProxyOptions":
				gvrList = append(gvrList, schema.GroupVersionResource{Group: "", Version: "v1", Resource: "services/proxy"})
			default:
				_, gvr, err := m.client.DiscoveryClient.FindResource(gv, k)
				if err != nil {
					m.log.Error(err, "unable to convert GVK to GVR", "GVK", gvk)
					continue
				}
				if strings.Contains(gvk, "*") {
					gvrList = append(gvrList, schema.GroupVersionResource{Group: gvr.Group, Version: "*", Resource: gvr.Resource})
				} else {
					gvrList = append(gvrList, gvr)
				}
			}
		}
	}

	var groups, versions, rsrcs []string
	if val, ok := dst.rule[apiGroups]; ok {
		groups = make([]string, len(val.([]string)))
		copy(groups, val.([]string))
	}

	if val, ok := dst.rule[apiVersions]; ok {
		versions = make([]string, len(val.([]string)))
		copy(versions, val.([]string))
	}
	if val, ok := dst.rule[resources]; ok {
		rsrcs = make([]string, len(val.([]string)))
		copy(rsrcs, val.([]string))
	}

	for _, gvr := range gvrList {
		groups = append(groups, gvr.Group)
		versions = append(versions, gvr.Version)
		rsrcs = append(rsrcs, gvr.Resource)
	}

	if utils.ContainsString(rsrcs, "pods") {
		rsrcs = append(rsrcs, "pods/ephemeralcontainers")
	}

	dst.rule[apiGroups] = removeDuplicates(groups)
	dst.rule[apiVersions] = removeDuplicates(versions)
	dst.rule[resources] = removeDuplicates(rsrcs)

	if policy.Spec.WebhookTimeoutSeconds != nil {
		if dst.maxWebhookTimeout < int64(*policy.Spec.WebhookTimeoutSeconds) {
			dst.maxWebhookTimeout = int64(*policy.Spec.WebhookTimeoutSeconds)
		}
	}
}

func removeDuplicates(items []string) (res []string) {
	set := make(map[string]int)
	for _, item := range items {
		if _, ok := set[item]; !ok {
			set[item] = 1
			res = append(res, item)
		}
	}
	return
}

func newWebhook(kind string, timeout int64, failurePolicy kyverno.FailurePolicyType) *webhook {
	return &webhook{
		kind:              kind,
		maxWebhookTimeout: timeout,
		failurePolicy:     failurePolicy,
		rule:              make(map[string]interface{}),
	}
}

func webhookKey(webhookKind, failurePolicy string) string {
	return strings.Join([]string{webhookKind, failurePolicy}, "/")
}

func hasWildcard(policy interface{}) bool {
	if p, ok := policy.(*kyverno.ClusterPolicy); ok {
		for _, rule := range p.GetRules() {
			if kinds := rule.MatchKinds(); utils.ContainsString(kinds, "*") {
				return true
			}
		}
	}

	if p, ok := policy.(*kyverno.Policy); ok {
		for _, rule := range p.GetRules() {
			if kinds := rule.MatchKinds(); utils.ContainsString(kinds, "*") {
				return true
			}
		}
	}
	return false
}

func setWildcardConfig(w *webhook) {
	w.rule[apiGroups] = []string{"*"}
	w.rule[apiVersions] = []string{"*"}
	w.rule[resources] = []string{"*/*"}
}