/*
Copyright 2018 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 testing

import (
	"net/url"
	"sync"

	registrationv1beta1 "k8s.io/api/admissionregistration/v1beta1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apiserver/pkg/admission"
	"k8s.io/apiserver/pkg/admission/plugin/webhook/testcerts"
	"k8s.io/apiserver/pkg/authentication/user"
	"k8s.io/client-go/informers"
	"k8s.io/client-go/kubernetes"
	fakeclientset "k8s.io/client-go/kubernetes/fake"
)

var matchEverythingRules = []registrationv1beta1.RuleWithOperations{{
	Operations: []registrationv1beta1.OperationType{registrationv1beta1.OperationAll},
	Rule: registrationv1beta1.Rule{
		APIGroups:   []string{"*"},
		APIVersions: []string{"*"},
		Resources:   []string{"*/*"},
	},
}}

var sideEffectsUnknown = registrationv1beta1.SideEffectClassUnknown
var sideEffectsNone = registrationv1beta1.SideEffectClassNone
var sideEffectsSome = registrationv1beta1.SideEffectClassSome
var sideEffectsNoneOnDryRun = registrationv1beta1.SideEffectClassNoneOnDryRun

// NewFakeDataSource returns a mock client and informer returning the given webhooks.
func NewFakeDataSource(name string, webhooks []registrationv1beta1.Webhook, mutating bool, stopCh <-chan struct{}) (clientset kubernetes.Interface, factory informers.SharedInformerFactory) {
	var objs = []runtime.Object{
		&corev1.Namespace{
			ObjectMeta: metav1.ObjectMeta{
				Name: name,
				Labels: map[string]string{
					"runlevel": "0",
				},
			},
		},
	}
	if mutating {
		objs = append(objs, &registrationv1beta1.MutatingWebhookConfiguration{
			ObjectMeta: metav1.ObjectMeta{
				Name: "test-webhooks",
			},
			Webhooks: webhooks,
		})
	} else {
		objs = append(objs, &registrationv1beta1.ValidatingWebhookConfiguration{
			ObjectMeta: metav1.ObjectMeta{
				Name: "test-webhooks",
			},
			Webhooks: webhooks,
		})
	}

	client := fakeclientset.NewSimpleClientset(objs...)
	informerFactory := informers.NewSharedInformerFactory(client, 0)

	return client, informerFactory
}

func newAttributesRecord(object metav1.Object, oldObject metav1.Object, kind schema.GroupVersionKind, namespace string, name string, resource string, labels map[string]string, dryRun bool) admission.Attributes {
	object.SetName(name)
	object.SetNamespace(namespace)
	objectLabels := map[string]string{resource + ".name": name}
	for k, v := range labels {
		objectLabels[k] = v
	}
	object.SetLabels(objectLabels)

	oldObject.SetName(name)
	oldObject.SetNamespace(namespace)

	gvr := kind.GroupVersion().WithResource(resource)
	subResource := ""
	userInfo := user.DefaultInfo{
		Name: "webhook-test",
		UID:  "webhook-test",
	}

	return &FakeAttributes{
		Attributes: admission.NewAttributesRecord(object.(runtime.Object), oldObject.(runtime.Object), kind, namespace, name, gvr, subResource, admission.Update, dryRun, &userInfo),
	}
}

// FakeAttributes decorate admission.Attributes. It's used to trace the added annotations.
type FakeAttributes struct {
	admission.Attributes
	annotations map[string]string
	mutex       sync.Mutex
}

// AddAnnotation adds an annotation key value pair to FakeAttributes
func (f *FakeAttributes) AddAnnotation(k, v string) error {
	f.mutex.Lock()
	defer f.mutex.Unlock()
	if err := f.Attributes.AddAnnotation(k, v); err != nil {
		return err
	}
	if f.annotations == nil {
		f.annotations = make(map[string]string)
	}
	f.annotations[k] = v
	return nil
}

// GetAnnotations reads annotations from FakeAttributes
func (f *FakeAttributes) GetAnnotations() map[string]string {
	f.mutex.Lock()
	defer f.mutex.Unlock()
	return f.annotations
}

// NewAttribute returns static admission Attributes for testing.
func NewAttribute(namespace string, labels map[string]string, dryRun bool) admission.Attributes {
	// Set up a test object for the call
	object := corev1.Pod{
		TypeMeta: metav1.TypeMeta{
			APIVersion: "v1",
			Kind:       "Pod",
		},
	}
	oldObject := corev1.Pod{}
	kind := corev1.SchemeGroupVersion.WithKind("Pod")
	name := "my-pod"

	return newAttributesRecord(&object, &oldObject, kind, namespace, name, "pod", labels, dryRun)
}

// NewAttributeUnstructured returns static admission Attributes for testing with custom resources.
func NewAttributeUnstructured(namespace string, labels map[string]string, dryRun bool) admission.Attributes {
	// Set up a test object for the call
	object := unstructured.Unstructured{}
	object.SetKind("TestCRD")
	object.SetAPIVersion("custom.resource/v1")
	oldObject := unstructured.Unstructured{}
	oldObject.SetKind("TestCRD")
	oldObject.SetAPIVersion("custom.resource/v1")
	kind := object.GroupVersionKind()
	name := "my-test-crd"

	return newAttributesRecord(&object, &oldObject, kind, namespace, name, "crd", labels, dryRun)
}

type urlConfigGenerator struct {
	baseURL *url.URL
}

func (c urlConfigGenerator) ccfgURL(urlPath string) registrationv1beta1.WebhookClientConfig {
	u2 := *c.baseURL
	u2.Path = urlPath
	urlString := u2.String()
	return registrationv1beta1.WebhookClientConfig{
		URL:      &urlString,
		CABundle: testcerts.CACert,
	}
}

// Test is a webhook test case.
type Test struct {
	Name              string
	Webhooks          []registrationv1beta1.Webhook
	Path              string
	IsCRD             bool
	IsDryRun          bool
	AdditionalLabels  map[string]string
	ExpectLabels      map[string]string
	ExpectAllow       bool
	ErrorContains     string
	ExpectAnnotations map[string]string
}

// NewNonMutatingTestCases returns test cases with a given base url.
// All test cases in NewNonMutatingTestCases have no Patch set in
// AdmissionResponse. The test cases are used by both MutatingAdmissionWebhook
// and ValidatingAdmissionWebhook.
func NewNonMutatingTestCases(url *url.URL) []Test {
	policyFail := registrationv1beta1.Fail
	policyIgnore := registrationv1beta1.Ignore
	ccfgURL := urlConfigGenerator{url}.ccfgURL

	return []Test{
		{
			Name: "no match",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:         "nomatch",
				ClientConfig: ccfgSVC("disallow"),
				Rules: []registrationv1beta1.RuleWithOperations{{
					Operations: []registrationv1beta1.OperationType{registrationv1beta1.Create},
				}},
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ExpectAllow: true,
		},
		{
			Name: "match & allow",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "allow.example.com",
				ClientConfig:      ccfgSVC("allow"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ExpectAllow:       true,
			ExpectAnnotations: map[string]string{"allow.example.com/key1": "value1"},
		},
		{
			Name: "match & disallow",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "disallow",
				ClientConfig:      ccfgSVC("disallow"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ErrorContains: "without explanation",
		},
		{
			Name: "match & disallow ii",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "disallowReason",
				ClientConfig:      ccfgSVC("disallowReason"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},

			ErrorContains: "you shall not pass",
		},
		{
			Name: "match & disallow & but allowed because namespaceSelector exempt the ns",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:         "disallow",
				ClientConfig: ccfgSVC("disallow"),
				Rules:        newMatchEverythingRules(),
				NamespaceSelector: &metav1.LabelSelector{
					MatchExpressions: []metav1.LabelSelectorRequirement{{
						Key:      "runlevel",
						Values:   []string{"1"},
						Operator: metav1.LabelSelectorOpIn,
					}},
				},
			}},

			ExpectAllow: true,
		},
		{
			Name: "match & disallow & but allowed because namespaceSelector exempt the ns ii",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:         "disallow",
				ClientConfig: ccfgSVC("disallow"),
				Rules:        newMatchEverythingRules(),
				NamespaceSelector: &metav1.LabelSelector{
					MatchExpressions: []metav1.LabelSelectorRequirement{{
						Key:      "runlevel",
						Values:   []string{"0"},
						Operator: metav1.LabelSelectorOpNotIn,
					}},
				},
			}},
			ExpectAllow: true,
		},
		{
			Name: "match & fail (but allow because fail open)",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "internalErr A",
				ClientConfig:      ccfgSVC("internalErr"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyIgnore,
			}, {
				Name:              "internalErr B",
				ClientConfig:      ccfgSVC("internalErr"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyIgnore,
			}, {
				Name:              "internalErr C",
				ClientConfig:      ccfgSVC("internalErr"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyIgnore,
			}},

			ExpectAllow: true,
		},
		{
			Name: "match & fail (but disallow because fail close on nil FailurePolicy)",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "internalErr A",
				ClientConfig:      ccfgSVC("internalErr"),
				NamespaceSelector: &metav1.LabelSelector{},
				Rules:             matchEverythingRules,
			}, {
				Name:              "internalErr B",
				ClientConfig:      ccfgSVC("internalErr"),
				NamespaceSelector: &metav1.LabelSelector{},
				Rules:             matchEverythingRules,
			}, {
				Name:              "internalErr C",
				ClientConfig:      ccfgSVC("internalErr"),
				NamespaceSelector: &metav1.LabelSelector{},
				Rules:             matchEverythingRules,
			}},
			ExpectAllow: false,
		},
		{
			Name: "match & fail (but fail because fail closed)",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "internalErr A",
				ClientConfig:      ccfgSVC("internalErr"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyFail,
			}, {
				Name:              "internalErr B",
				ClientConfig:      ccfgSVC("internalErr"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyFail,
			}, {
				Name:              "internalErr C",
				ClientConfig:      ccfgSVC("internalErr"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyFail,
			}},
			ExpectAllow: false,
		},
		{
			Name: "match & allow (url)",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "allow.example.com",
				ClientConfig:      ccfgURL("allow"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ExpectAllow:       true,
			ExpectAnnotations: map[string]string{"allow.example.com/key1": "value1"},
		},
		{
			Name: "match & disallow (url)",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "disallow",
				ClientConfig:      ccfgURL("disallow"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ErrorContains: "without explanation",
		}, {
			Name: "absent response and fail open",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "nilResponse",
				ClientConfig:      ccfgURL("nilResponse"),
				FailurePolicy:     &policyIgnore,
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ExpectAllow: true,
		},
		{
			Name: "absent response and fail closed",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "nilResponse",
				ClientConfig:      ccfgURL("nilResponse"),
				FailurePolicy:     &policyFail,
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ErrorContains: "Webhook response was absent",
		},
		{
			Name: "no match dry run",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:         "nomatch",
				ClientConfig: ccfgSVC("allow"),
				Rules: []registrationv1beta1.RuleWithOperations{{
					Operations: []registrationv1beta1.OperationType{registrationv1beta1.Create},
				}},
				NamespaceSelector: &metav1.LabelSelector{},
				SideEffects:       &sideEffectsSome,
			}},
			IsDryRun:    true,
			ExpectAllow: true,
		},
		{
			Name: "match dry run side effects Unknown",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "allow",
				ClientConfig:      ccfgSVC("allow"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				SideEffects:       &sideEffectsUnknown,
			}},
			IsDryRun:      true,
			ErrorContains: "does not support dry run",
		},
		{
			Name: "match dry run side effects None",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "allow",
				ClientConfig:      ccfgSVC("allow"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				SideEffects:       &sideEffectsNone,
			}},
			IsDryRun:          true,
			ExpectAllow:       true,
			ExpectAnnotations: map[string]string{"allow/key1": "value1"},
		},
		{
			Name: "match dry run side effects Some",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "allow",
				ClientConfig:      ccfgSVC("allow"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				SideEffects:       &sideEffectsSome,
			}},
			IsDryRun:      true,
			ErrorContains: "does not support dry run",
		},
		{
			Name: "match dry run side effects NoneOnDryRun",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "allow",
				ClientConfig:      ccfgSVC("allow"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				SideEffects:       &sideEffectsNoneOnDryRun,
			}},
			IsDryRun:          true,
			ExpectAllow:       true,
			ExpectAnnotations: map[string]string{"allow/key1": "value1"},
		},
		{
			Name: "illegal annotation format",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "invalidAnnotation",
				ClientConfig:      ccfgURL("invalidAnnotation"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ExpectAllow: true,
		},
		// No need to test everything with the url case, since only the
		// connection is different.
	}
}

// NewMutatingTestCases returns test cases with a given base url.
// All test cases in NewMutatingTestCases have Patch set in
// AdmissionResponse. The test cases are only used by both MutatingAdmissionWebhook.
func NewMutatingTestCases(url *url.URL) []Test {
	return []Test{
		{
			Name: "match & remove label",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "removelabel.example.com",
				ClientConfig:      ccfgSVC("removeLabel"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ExpectAllow:       true,
			AdditionalLabels:  map[string]string{"remove": "me"},
			ExpectLabels:      map[string]string{"pod.name": "my-pod"},
			ExpectAnnotations: map[string]string{"removelabel.example.com/key1": "value1"},
		},
		{
			Name: "match & add label",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "addLabel",
				ClientConfig:      ccfgSVC("addLabel"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ExpectAllow:  true,
			ExpectLabels: map[string]string{"pod.name": "my-pod", "added": "test"},
		},
		{
			Name: "match CRD & add label",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "addLabel",
				ClientConfig:      ccfgSVC("addLabel"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			IsCRD:        true,
			ExpectAllow:  true,
			ExpectLabels: map[string]string{"crd.name": "my-test-crd", "added": "test"},
		},
		{
			Name: "match CRD & remove label",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "removelabel.example.com",
				ClientConfig:      ccfgSVC("removeLabel"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			IsCRD:             true,
			ExpectAllow:       true,
			AdditionalLabels:  map[string]string{"remove": "me"},
			ExpectLabels:      map[string]string{"crd.name": "my-test-crd"},
			ExpectAnnotations: map[string]string{"removelabel.example.com/key1": "value1"},
		},
		{
			Name: "match & invalid mutation",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "invalidMutation",
				ClientConfig:      ccfgSVC("invalidMutation"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
			}},
			ErrorContains: "invalid character",
		},
		{
			Name: "match & remove label dry run unsupported",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "removeLabel",
				ClientConfig:      ccfgSVC("removeLabel"),
				Rules:             matchEverythingRules,
				NamespaceSelector: &metav1.LabelSelector{},
				SideEffects:       &sideEffectsUnknown,
			}},
			IsDryRun:      true,
			ErrorContains: "does not support dry run",
		},
		// No need to test everything with the url case, since only the
		// connection is different.
	}
}

// CachedTest is a test case for the client manager.
type CachedTest struct {
	Name            string
	Webhooks        []registrationv1beta1.Webhook
	ExpectAllow     bool
	ExpectCacheMiss bool
}

// NewCachedClientTestcases returns a set of client manager test cases.
func NewCachedClientTestcases(url *url.URL) []CachedTest {
	policyIgnore := registrationv1beta1.Ignore
	ccfgURL := urlConfigGenerator{url}.ccfgURL

	return []CachedTest{
		{
			Name: "uncached: service webhook, path 'allow'",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "cache1",
				ClientConfig:      ccfgSVC("allow"),
				Rules:             newMatchEverythingRules(),
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyIgnore,
			}},
			ExpectAllow:     true,
			ExpectCacheMiss: true,
		},
		{
			Name: "uncached: service webhook, path 'internalErr'",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "cache2",
				ClientConfig:      ccfgSVC("internalErr"),
				Rules:             newMatchEverythingRules(),
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyIgnore,
			}},
			ExpectAllow:     true,
			ExpectCacheMiss: true,
		},
		{
			Name: "cached: service webhook, path 'allow'",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "cache3",
				ClientConfig:      ccfgSVC("allow"),
				Rules:             newMatchEverythingRules(),
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyIgnore,
			}},
			ExpectAllow:     true,
			ExpectCacheMiss: false,
		},
		{
			Name: "uncached: url webhook, path 'allow'",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "cache4",
				ClientConfig:      ccfgURL("allow"),
				Rules:             newMatchEverythingRules(),
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyIgnore,
			}},
			ExpectAllow:     true,
			ExpectCacheMiss: true,
		},
		{
			Name: "cached: service webhook, path 'allow'",
			Webhooks: []registrationv1beta1.Webhook{{
				Name:              "cache5",
				ClientConfig:      ccfgURL("allow"),
				Rules:             newMatchEverythingRules(),
				NamespaceSelector: &metav1.LabelSelector{},
				FailurePolicy:     &policyIgnore,
			}},
			ExpectAllow:     true,
			ExpectCacheMiss: false,
		},
	}
}

// ccfgSVC returns a client config using the service reference mechanism.
func ccfgSVC(urlPath string) registrationv1beta1.WebhookClientConfig {
	return registrationv1beta1.WebhookClientConfig{
		Service: &registrationv1beta1.ServiceReference{
			Name:      "webhook-test",
			Namespace: "default",
			Path:      &urlPath,
		},
		CABundle: testcerts.CACert,
	}
}

func newMatchEverythingRules() []registrationv1beta1.RuleWithOperations {
	return []registrationv1beta1.RuleWithOperations{{
		Operations: []registrationv1beta1.OperationType{registrationv1beta1.OperationAll},
		Rule: registrationv1beta1.Rule{
			APIGroups:   []string{"*"},
			APIVersions: []string{"*"},
			Resources:   []string{"*/*"},
		},
	}}
}