/*
Copyright 2019 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package generic

import (
	"fmt"
	"strings"
	"testing"

	v1 "k8s.io/api/admissionregistration/v1"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apiserver/pkg/admission"
	"k8s.io/apiserver/pkg/admission/plugin/webhook"
	"k8s.io/apiserver/pkg/admission/plugin/webhook/predicates/namespace"
	"k8s.io/apiserver/pkg/admission/plugin/webhook/predicates/object"
)

func gvr(group, version, resource string) schema.GroupVersionResource {
	return schema.GroupVersionResource{Group: group, Version: version, Resource: resource}
}

func gvk(group, version, kind string) schema.GroupVersionKind {
	return schema.GroupVersionKind{Group: group, Version: version, Kind: kind}
}

func TestShouldCallHook(t *testing.T) {
	a := &Webhook{namespaceMatcher: &namespace.Matcher{}, objectMatcher: &object.Matcher{}}

	allScopes := v1.AllScopes
	exactMatch := v1.Exact
	equivalentMatch := v1.Equivalent

	mapper := runtime.NewEquivalentResourceRegistryWithIdentity(func(resource schema.GroupResource) string {
		if resource.Resource == "deployments" {
			// co-locate deployments in all API groups
			return "/deployments"
		}
		return ""
	})
	mapper.RegisterKindFor(gvr("extensions", "v1beta1", "deployments"), "", gvk("extensions", "v1beta1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1", "deployments"), "", gvk("apps", "v1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "deployments"), "", gvk("apps", "v1beta1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha1", "deployments"), "", gvk("apps", "v1alpha1", "Deployment"))

	mapper.RegisterKindFor(gvr("extensions", "v1beta1", "deployments"), "scale", gvk("extensions", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1", "deployments"), "scale", gvk("autoscaling", "v1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "deployments"), "scale", gvk("apps", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha1", "deployments"), "scale", gvk("apps", "v1alpha1", "Scale"))

	// register invalid kinds to trigger an error
	mapper.RegisterKindFor(gvr("example.com", "v1", "widgets"), "", gvk("", "", ""))
	mapper.RegisterKindFor(gvr("example.com", "v2", "widgets"), "", gvk("", "", ""))

	interfaces := &admission.RuntimeObjectInterfaces{EquivalentResourceMapper: mapper}

	testcases := []struct {
		name string

		webhook *v1.ValidatingWebhook
		attrs   admission.Attributes

		expectCall            bool
		expectErr             string
		expectCallResource    schema.GroupVersionResource
		expectCallSubresource string
		expectCallKind        schema.GroupVersionKind
	}{
		{
			name:       "no rules (just write)",
			webhook:    &v1.ValidatingWebhook{NamespaceSelector: &metav1.LabelSelector{}, Rules: []v1.RuleWithOperations{}},
			attrs:      admission.NewAttributesRecord(nil, nil, gvk("apps", "v1", "Deployment"), "ns", "name", gvr("apps", "v1", "deployments"), "", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall: false,
		},
		{
			name: "invalid kind lookup",
			webhook: &v1.ValidatingWebhook{
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				MatchPolicy:       &equivalentMatch,
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"example.com"}, APIVersions: []string{"v1"}, Resources: []string{"widgets"}, Scope: &allScopes},
				}}},
			attrs:      admission.NewAttributesRecord(nil, nil, gvk("example.com", "v2", "Widget"), "ns", "name", gvr("example.com", "v2", "widgets"), "", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall: false,
			expectErr:  "unknown kind",
		},
		{
			name: "wildcard rule, match as requested",
			webhook: &v1.ValidatingWebhook{
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"*"}, APIVersions: []string{"*"}, Resources: []string{"*"}, Scope: &allScopes},
				}}},
			attrs:                 admission.NewAttributesRecord(nil, nil, gvk("apps", "v1", "Deployment"), "ns", "name", gvr("apps", "v1", "deployments"), "", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall:            true,
			expectCallKind:        gvk("apps", "v1", "Deployment"),
			expectCallResource:    gvr("apps", "v1", "deployments"),
			expectCallSubresource: "",
		},
		{
			name: "specific rules, prefer exact match",
			webhook: &v1.ValidatingWebhook{
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}}},
			attrs:                 admission.NewAttributesRecord(nil, nil, gvk("apps", "v1", "Deployment"), "ns", "name", gvr("apps", "v1", "deployments"), "", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall:            true,
			expectCallKind:        gvk("apps", "v1", "Deployment"),
			expectCallResource:    gvr("apps", "v1", "deployments"),
			expectCallSubresource: "",
		},
		{
			name: "specific rules, match miss",
			webhook: &v1.ValidatingWebhook{
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}}},
			attrs:      admission.NewAttributesRecord(nil, nil, gvk("apps", "v1", "Deployment"), "ns", "name", gvr("apps", "v1", "deployments"), "", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall: false,
		},
		{
			name: "specific rules, exact match miss",
			webhook: &v1.ValidatingWebhook{
				MatchPolicy:       &exactMatch,
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}}},
			attrs:      admission.NewAttributesRecord(nil, nil, gvk("apps", "v1", "Deployment"), "ns", "name", gvr("apps", "v1", "deployments"), "", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall: false,
		},
		{
			name: "specific rules, equivalent match, prefer extensions",
			webhook: &v1.ValidatingWebhook{
				MatchPolicy:       &equivalentMatch,
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}}},
			attrs:                 admission.NewAttributesRecord(nil, nil, gvk("apps", "v1", "Deployment"), "ns", "name", gvr("apps", "v1", "deployments"), "", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall:            true,
			expectCallKind:        gvk("extensions", "v1beta1", "Deployment"),
			expectCallResource:    gvr("extensions", "v1beta1", "deployments"),
			expectCallSubresource: "",
		},
		{
			name: "specific rules, equivalent match, prefer apps",
			webhook: &v1.ValidatingWebhook{
				MatchPolicy:       &equivalentMatch,
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments"}, Scope: &allScopes},
				}}},
			attrs:                 admission.NewAttributesRecord(nil, nil, gvk("apps", "v1", "Deployment"), "ns", "name", gvr("apps", "v1", "deployments"), "", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall:            true,
			expectCallKind:        gvk("apps", "v1beta1", "Deployment"),
			expectCallResource:    gvr("apps", "v1beta1", "deployments"),
			expectCallSubresource: "",
		},

		{
			name: "specific rules, subresource prefer exact match",
			webhook: &v1.ValidatingWebhook{
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}}},
			attrs:                 admission.NewAttributesRecord(nil, nil, gvk("autoscaling", "v1", "Scale"), "ns", "name", gvr("apps", "v1", "deployments"), "scale", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall:            true,
			expectCallKind:        gvk("autoscaling", "v1", "Scale"),
			expectCallResource:    gvr("apps", "v1", "deployments"),
			expectCallSubresource: "scale",
		},
		{
			name: "specific rules, subresource match miss",
			webhook: &v1.ValidatingWebhook{
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}}},
			attrs:      admission.NewAttributesRecord(nil, nil, gvk("autoscaling", "v1", "Scale"), "ns", "name", gvr("apps", "v1", "deployments"), "scale", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall: false,
		},
		{
			name: "specific rules, subresource exact match miss",
			webhook: &v1.ValidatingWebhook{
				MatchPolicy:       &exactMatch,
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}}},
			attrs:      admission.NewAttributesRecord(nil, nil, gvk("autoscaling", "v1", "Scale"), "ns", "name", gvr("apps", "v1", "deployments"), "scale", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall: false,
		},
		{
			name: "specific rules, subresource equivalent match, prefer extensions",
			webhook: &v1.ValidatingWebhook{
				MatchPolicy:       &equivalentMatch,
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}}},
			attrs:                 admission.NewAttributesRecord(nil, nil, gvk("autoscaling", "v1", "Scale"), "ns", "name", gvr("apps", "v1", "deployments"), "scale", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall:            true,
			expectCallKind:        gvk("extensions", "v1beta1", "Scale"),
			expectCallResource:    gvr("extensions", "v1beta1", "deployments"),
			expectCallSubresource: "scale",
		},
		{
			name: "specific rules, subresource equivalent match, prefer apps",
			webhook: &v1.ValidatingWebhook{
				MatchPolicy:       &equivalentMatch,
				NamespaceSelector: &metav1.LabelSelector{},
				ObjectSelector:    &metav1.LabelSelector{},
				Rules: []v1.RuleWithOperations{{
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}, {
					Operations: []v1.OperationType{"*"},
					Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
				}}},
			attrs:                 admission.NewAttributesRecord(nil, nil, gvk("autoscaling", "v1", "Scale"), "ns", "name", gvr("apps", "v1", "deployments"), "scale", admission.Create, &metav1.CreateOptions{}, false, nil),
			expectCall:            true,
			expectCallKind:        gvk("apps", "v1beta1", "Scale"),
			expectCallResource:    gvr("apps", "v1beta1", "deployments"),
			expectCallSubresource: "scale",
		},
	}

	for i, testcase := range testcases {
		t.Run(testcase.name, func(t *testing.T) {
			invocation, err := a.ShouldCallHook(webhook.NewValidatingWebhookAccessor(fmt.Sprintf("webhook-%d", i), fmt.Sprintf("webhook-cfg-%d", i), testcase.webhook), testcase.attrs, interfaces)
			if err != nil {
				if len(testcase.expectErr) == 0 {
					t.Fatal(err)
				}
				if !strings.Contains(err.Error(), testcase.expectErr) {
					t.Fatalf("expected error containing %q, got %s", testcase.expectErr, err.Error())
				}
				return
			} else if len(testcase.expectErr) > 0 {
				t.Fatalf("expected error %q, got no error and %#v", testcase.expectErr, invocation)
			}

			if invocation == nil {
				if testcase.expectCall {
					t.Fatal("expected invocation, got nil")
				}
				return
			}

			if !testcase.expectCall {
				t.Fatal("unexpected invocation")
			}

			if invocation.Kind != testcase.expectCallKind {
				t.Fatalf("expected %#v, got %#v", testcase.expectCallKind, invocation.Kind)
			}
			if invocation.Resource != testcase.expectCallResource {
				t.Fatalf("expected %#v, got %#v", testcase.expectCallResource, invocation.Resource)
			}
			if invocation.Subresource != testcase.expectCallSubresource {
				t.Fatalf("expected %#v, got %#v", testcase.expectCallSubresource, invocation.Subresource)
			}
		})
	}
}

type fakeNamespaceLister struct {
	namespaces map[string]*corev1.Namespace
}

func (f fakeNamespaceLister) List(selector labels.Selector) (ret []*corev1.Namespace, err error) {
	return nil, nil
}
func (f fakeNamespaceLister) Get(name string) (*corev1.Namespace, error) {
	ns, ok := f.namespaces[name]
	if ok {
		return ns, nil
	}
	return nil, errors.NewNotFound(corev1.Resource("namespaces"), name)
}

func BenchmarkShouldCallHookWithComplexSelector(b *testing.B) {
	allScopes := v1.AllScopes
	equivalentMatch := v1.Equivalent

	namespace1Labels := map[string]string{"ns": "ns1"}
	namespace1 := corev1.Namespace{
		ObjectMeta: metav1.ObjectMeta{
			Name:   "ns1",
			Labels: namespace1Labels,
		},
	}
	namespaceLister := fakeNamespaceLister{map[string]*corev1.Namespace{"ns": &namespace1}}

	mapper := runtime.NewEquivalentResourceRegistryWithIdentity(func(resource schema.GroupResource) string {
		if resource.Resource == "deployments" {
			// co-locate deployments in all API groups
			return "/deployments"
		}
		return ""
	})
	mapper.RegisterKindFor(gvr("extensions", "v1beta1", "deployments"), "", gvk("extensions", "v1beta1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1", "deployments"), "", gvk("apps", "v1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "deployments"), "", gvk("apps", "v1beta1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha1", "deployments"), "", gvk("apps", "v1alpha1", "Deployment"))

	mapper.RegisterKindFor(gvr("extensions", "v1beta1", "deployments"), "scale", gvk("extensions", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1", "deployments"), "scale", gvk("autoscaling", "v1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "deployments"), "scale", gvk("apps", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha1", "deployments"), "scale", gvk("apps", "v1alpha1", "Scale"))

	mapper.RegisterKindFor(gvr("apps", "v1", "statefulset"), "", gvk("apps", "v1", "StatefulSet"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "statefulset"), "", gvk("apps", "v1beta1", "StatefulSet"))
	mapper.RegisterKindFor(gvr("apps", "v1beta2", "statefulset"), "", gvk("apps", "v1beta2", "StatefulSet"))

	mapper.RegisterKindFor(gvr("apps", "v1", "statefulset"), "scale", gvk("apps", "v1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "statefulset"), "scale", gvk("apps", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha2", "statefulset"), "scale", gvk("apps", "v1beta2", "Scale"))

	nsSelector := make(map[string]string)
	for i := 0; i < 100; i++ {
		nsSelector[fmt.Sprintf("key-%d", i)] = fmt.Sprintf("val-%d", i)
	}

	wb := &v1.ValidatingWebhook{
		MatchPolicy:       &equivalentMatch,
		NamespaceSelector: &metav1.LabelSelector{MatchLabels: nsSelector},
		ObjectSelector:    &metav1.LabelSelector{},
		Rules: []v1.RuleWithOperations{
			{
				Operations: []v1.OperationType{"*"},
				Rule:       v1.Rule{APIGroups: []string{"apps"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
			},
			{
				Operations: []v1.OperationType{"*"},
				Rule:       v1.Rule{APIGroups: []string{"extensions"}, APIVersions: []string{"v1beta1"}, Resources: []string{"deployments", "deployments/scale"}, Scope: &allScopes},
			},
		},
	}

	wbAccessor := webhook.NewValidatingWebhookAccessor("webhook", "webhook-cfg", wb)
	attrs := admission.NewAttributesRecord(nil, nil, gvk("autoscaling", "v1", "Scale"), "ns", "name", gvr("apps", "v1", "deployments"), "scale", admission.Create, &metav1.CreateOptions{}, false, nil)
	interfaces := &admission.RuntimeObjectInterfaces{EquivalentResourceMapper: mapper}
	a := &Webhook{namespaceMatcher: &namespace.Matcher{NamespaceLister: namespaceLister}, objectMatcher: &object.Matcher{}}

	for i := 0; i < b.N; i++ {
		a.ShouldCallHook(wbAccessor, attrs, interfaces)
	}
}

func BenchmarkShouldCallHookWithComplexRule(b *testing.B) {
	allScopes := v1.AllScopes
	equivalentMatch := v1.Equivalent

	namespace1Labels := map[string]string{"ns": "ns1"}
	namespace1 := corev1.Namespace{
		ObjectMeta: metav1.ObjectMeta{
			Name:   "ns1",
			Labels: namespace1Labels,
		},
	}
	namespaceLister := fakeNamespaceLister{map[string]*corev1.Namespace{"ns": &namespace1}}

	mapper := runtime.NewEquivalentResourceRegistryWithIdentity(func(resource schema.GroupResource) string {
		if resource.Resource == "deployments" {
			// co-locate deployments in all API groups
			return "/deployments"
		}
		return ""
	})
	mapper.RegisterKindFor(gvr("extensions", "v1beta1", "deployments"), "", gvk("extensions", "v1beta1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1", "deployments"), "", gvk("apps", "v1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "deployments"), "", gvk("apps", "v1beta1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha1", "deployments"), "", gvk("apps", "v1alpha1", "Deployment"))

	mapper.RegisterKindFor(gvr("extensions", "v1beta1", "deployments"), "scale", gvk("extensions", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1", "deployments"), "scale", gvk("autoscaling", "v1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "deployments"), "scale", gvk("apps", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha1", "deployments"), "scale", gvk("apps", "v1alpha1", "Scale"))

	mapper.RegisterKindFor(gvr("apps", "v1", "statefulset"), "", gvk("apps", "v1", "StatefulSet"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "statefulset"), "", gvk("apps", "v1beta1", "StatefulSet"))
	mapper.RegisterKindFor(gvr("apps", "v1beta2", "statefulset"), "", gvk("apps", "v1beta2", "StatefulSet"))

	mapper.RegisterKindFor(gvr("apps", "v1", "statefulset"), "scale", gvk("apps", "v1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "statefulset"), "scale", gvk("apps", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha2", "statefulset"), "scale", gvk("apps", "v1beta2", "Scale"))

	wb := &v1.ValidatingWebhook{
		MatchPolicy:       &equivalentMatch,
		NamespaceSelector: &metav1.LabelSelector{MatchLabels: map[string]string{"a": "b"}},
		ObjectSelector:    &metav1.LabelSelector{},
		Rules:             []v1.RuleWithOperations{},
	}

	for i := 0; i < 100; i++ {
		rule := v1.RuleWithOperations{
			Operations: []v1.OperationType{"*"},
			Rule: v1.Rule{
				APIGroups:   []string{fmt.Sprintf("app-%d", i)},
				APIVersions: []string{fmt.Sprintf("v%d", i)},
				Resources:   []string{fmt.Sprintf("resource%d", i), fmt.Sprintf("resource%d/scale", i)},
				Scope:       &allScopes,
			},
		}
		wb.Rules = append(wb.Rules, rule)
	}

	wbAccessor := webhook.NewValidatingWebhookAccessor("webhook", "webhook-cfg", wb)
	attrs := admission.NewAttributesRecord(nil, nil, gvk("autoscaling", "v1", "Scale"), "ns", "name", gvr("apps", "v1", "deployments"), "scale", admission.Create, &metav1.CreateOptions{}, false, nil)
	interfaces := &admission.RuntimeObjectInterfaces{EquivalentResourceMapper: mapper}
	a := &Webhook{namespaceMatcher: &namespace.Matcher{NamespaceLister: namespaceLister}, objectMatcher: &object.Matcher{}}

	for i := 0; i < b.N; i++ {
		a.ShouldCallHook(wbAccessor, attrs, interfaces)
	}
}

func BenchmarkShouldCallHookWithComplexSelectorAndRule(b *testing.B) {
	allScopes := v1.AllScopes
	equivalentMatch := v1.Equivalent

	namespace1Labels := map[string]string{"ns": "ns1"}
	namespace1 := corev1.Namespace{
		ObjectMeta: metav1.ObjectMeta{
			Name:   "ns1",
			Labels: namespace1Labels,
		},
	}
	namespaceLister := fakeNamespaceLister{map[string]*corev1.Namespace{"ns": &namespace1}}

	mapper := runtime.NewEquivalentResourceRegistryWithIdentity(func(resource schema.GroupResource) string {
		if resource.Resource == "deployments" {
			// co-locate deployments in all API groups
			return "/deployments"
		}
		return ""
	})
	mapper.RegisterKindFor(gvr("extensions", "v1beta1", "deployments"), "", gvk("extensions", "v1beta1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1", "deployments"), "", gvk("apps", "v1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "deployments"), "", gvk("apps", "v1beta1", "Deployment"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha1", "deployments"), "", gvk("apps", "v1alpha1", "Deployment"))

	mapper.RegisterKindFor(gvr("extensions", "v1beta1", "deployments"), "scale", gvk("extensions", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1", "deployments"), "scale", gvk("autoscaling", "v1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "deployments"), "scale", gvk("apps", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha1", "deployments"), "scale", gvk("apps", "v1alpha1", "Scale"))

	mapper.RegisterKindFor(gvr("apps", "v1", "statefulset"), "", gvk("apps", "v1", "StatefulSet"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "statefulset"), "", gvk("apps", "v1beta1", "StatefulSet"))
	mapper.RegisterKindFor(gvr("apps", "v1beta2", "statefulset"), "", gvk("apps", "v1beta2", "StatefulSet"))

	mapper.RegisterKindFor(gvr("apps", "v1", "statefulset"), "scale", gvk("apps", "v1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1beta1", "statefulset"), "scale", gvk("apps", "v1beta1", "Scale"))
	mapper.RegisterKindFor(gvr("apps", "v1alpha2", "statefulset"), "scale", gvk("apps", "v1beta2", "Scale"))

	nsSelector := make(map[string]string)
	for i := 0; i < 100; i++ {
		nsSelector[fmt.Sprintf("key-%d", i)] = fmt.Sprintf("val-%d", i)
	}

	wb := &v1.ValidatingWebhook{
		MatchPolicy:       &equivalentMatch,
		NamespaceSelector: &metav1.LabelSelector{MatchLabels: nsSelector},
		ObjectSelector:    &metav1.LabelSelector{},
		Rules:             []v1.RuleWithOperations{},
	}

	for i := 0; i < 100; i++ {
		rule := v1.RuleWithOperations{
			Operations: []v1.OperationType{"*"},
			Rule: v1.Rule{
				APIGroups:   []string{fmt.Sprintf("app-%d", i)},
				APIVersions: []string{fmt.Sprintf("v%d", i)},
				Resources:   []string{fmt.Sprintf("resource%d", i), fmt.Sprintf("resource%d/scale", i)},
				Scope:       &allScopes,
			},
		}
		wb.Rules = append(wb.Rules, rule)
	}

	wbAccessor := webhook.NewValidatingWebhookAccessor("webhook", "webhook-cfg", wb)
	attrs := admission.NewAttributesRecord(nil, nil, gvk("autoscaling", "v1", "Scale"), "ns", "name", gvr("apps", "v1", "deployments"), "scale", admission.Create, &metav1.CreateOptions{}, false, nil)
	interfaces := &admission.RuntimeObjectInterfaces{EquivalentResourceMapper: mapper}
	a := &Webhook{namespaceMatcher: &namespace.Matcher{NamespaceLister: namespaceLister}, objectMatcher: &object.Matcher{}}

	for i := 0; i < b.N; i++ {
		a.ShouldCallHook(wbAccessor, attrs, interfaces)
	}
}