/*
Copyright 2016 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 poddisruptionbudget

import (
	"reflect"
	"testing"

	"github.com/google/go-cmp/cmp"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/intstr"
	genericapirequest "k8s.io/apiserver/pkg/endpoints/request"
	utilfeature "k8s.io/apiserver/pkg/util/feature"
	featuregatetesting "k8s.io/component-base/featuregate/testing"
	"k8s.io/kubernetes/pkg/apis/policy"
	"k8s.io/kubernetes/pkg/features"
)

type unhealthyPodEvictionPolicyStrategyTestCase struct {
	name                                                       string
	enableUnhealthyPodEvictionPolicy                           bool
	disablePDBUnhealthyPodEvictionPolicyFeatureGateAfterCreate bool
	unhealthyPodEvictionPolicy                                 *policy.UnhealthyPodEvictionPolicyType
	expectedUnhealthyPodEvictionPolicy                         *policy.UnhealthyPodEvictionPolicyType
	expectedValidationErr                                      bool
	updateUnhealthyPodEvictionPolicy                           *policy.UnhealthyPodEvictionPolicyType
	expectedUpdateUnhealthyPodEvictionPolicy                   *policy.UnhealthyPodEvictionPolicyType
	expectedValidationUpdateErr                                bool
}

func TestPodDisruptionBudgetStrategy(t *testing.T) {
	tests := map[string]bool{
		"PodDisruptionBudget strategy with PDBUnhealthyPodEvictionPolicy feature gate disabled": false,
		"PodDisruptionBudget strategy with PDBUnhealthyPodEvictionPolicy feature gate enabled":  true,
	}

	for name, enableUnhealthyPodEvictionPolicy := range tests {
		t.Run(name, func(t *testing.T) {
			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.PDBUnhealthyPodEvictionPolicy, enableUnhealthyPodEvictionPolicy)()
			testPodDisruptionBudgetStrategy(t)
		})
	}

	healthyPolicyTests := []unhealthyPodEvictionPolicyStrategyTestCase{
		{
			name:                             "PodDisruptionBudget strategy with FeatureGate disabled should remove unhealthyPodEvictionPolicy",
			enableUnhealthyPodEvictionPolicy: false,
			unhealthyPodEvictionPolicy:       unhealthyPolicyPtr(policy.IfHealthyBudget),
			updateUnhealthyPodEvictionPolicy: unhealthyPolicyPtr(policy.IfHealthyBudget),
		},
		{
			name:                             "PodDisruptionBudget strategy with FeatureGate disabled should remove invalid unhealthyPodEvictionPolicy",
			enableUnhealthyPodEvictionPolicy: false,
			unhealthyPodEvictionPolicy:       unhealthyPolicyPtr("Invalid"),
			updateUnhealthyPodEvictionPolicy: unhealthyPolicyPtr("Invalid"),
		},
		{
			name:                             "PodDisruptionBudget strategy with FeatureGate enabled",
			enableUnhealthyPodEvictionPolicy: true,
		},
		{
			name:                                     "PodDisruptionBudget strategy with FeatureGate enabled should respect unhealthyPodEvictionPolicy",
			enableUnhealthyPodEvictionPolicy:         true,
			unhealthyPodEvictionPolicy:               unhealthyPolicyPtr(policy.AlwaysAllow),
			expectedUnhealthyPodEvictionPolicy:       unhealthyPolicyPtr(policy.AlwaysAllow),
			updateUnhealthyPodEvictionPolicy:         unhealthyPolicyPtr(policy.IfHealthyBudget),
			expectedUpdateUnhealthyPodEvictionPolicy: unhealthyPolicyPtr(policy.IfHealthyBudget),
		},
		{
			name:                             "PodDisruptionBudget strategy with FeatureGate enabled should fail invalid unhealthyPodEvictionPolicy",
			enableUnhealthyPodEvictionPolicy: true,
			unhealthyPodEvictionPolicy:       unhealthyPolicyPtr("Invalid"),
			expectedValidationErr:            true,
		},
		{
			name:                             "PodDisruptionBudget strategy with FeatureGate enabled should fail invalid unhealthyPodEvictionPolicy when updated",
			enableUnhealthyPodEvictionPolicy: true,
			updateUnhealthyPodEvictionPolicy: unhealthyPolicyPtr("Invalid"),
			expectedValidationUpdateErr:      true,
		},
		{
			name:                             "PodDisruptionBudget strategy with unhealthyPodEvictionPolicy should be updated when feature gate is disabled",
			enableUnhealthyPodEvictionPolicy: true,
			disablePDBUnhealthyPodEvictionPolicyFeatureGateAfterCreate: true,
			unhealthyPodEvictionPolicy:                                 unhealthyPolicyPtr(policy.AlwaysAllow),
			expectedUnhealthyPodEvictionPolicy:                         unhealthyPolicyPtr(policy.AlwaysAllow),
			updateUnhealthyPodEvictionPolicy:                           unhealthyPolicyPtr(policy.IfHealthyBudget),
			expectedUpdateUnhealthyPodEvictionPolicy:                   unhealthyPolicyPtr(policy.IfHealthyBudget),
		},
		{
			name:                             "PodDisruptionBudget strategy with unhealthyPodEvictionPolicy should not be updated to invalid when feature gate is disabled",
			enableUnhealthyPodEvictionPolicy: true,
			disablePDBUnhealthyPodEvictionPolicyFeatureGateAfterCreate: true,
			unhealthyPodEvictionPolicy:                                 unhealthyPolicyPtr(policy.AlwaysAllow),
			expectedUnhealthyPodEvictionPolicy:                         unhealthyPolicyPtr(policy.AlwaysAllow),
			updateUnhealthyPodEvictionPolicy:                           unhealthyPolicyPtr("Invalid"),
			expectedValidationUpdateErr:                                true,
			expectedUpdateUnhealthyPodEvictionPolicy:                   unhealthyPolicyPtr(policy.AlwaysAllow),
		},
	}

	for _, tc := range healthyPolicyTests {
		t.Run(tc.name, func(t *testing.T) {
			testPodDisruptionBudgetStrategyWithUnhealthyPodEvictionPolicy(t, tc)
		})
	}
}

func testPodDisruptionBudgetStrategyWithUnhealthyPodEvictionPolicy(t *testing.T, tc unhealthyPodEvictionPolicyStrategyTestCase) {
	defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.PDBUnhealthyPodEvictionPolicy, tc.enableUnhealthyPodEvictionPolicy)()
	ctx := genericapirequest.NewDefaultContext()
	if !Strategy.NamespaceScoped() {
		t.Errorf("PodDisruptionBudget must be namespace scoped")
	}
	if Strategy.AllowCreateOnUpdate() {
		t.Errorf("PodDisruptionBudget should not allow create on update")
	}

	validSelector := map[string]string{"a": "b"}
	minAvailable := intstr.FromInt32(3)
	pdb := &policy.PodDisruptionBudget{
		ObjectMeta: metav1.ObjectMeta{Name: "abc", Namespace: metav1.NamespaceDefault},
		Spec: policy.PodDisruptionBudgetSpec{
			MinAvailable:               &minAvailable,
			Selector:                   &metav1.LabelSelector{MatchLabels: validSelector},
			UnhealthyPodEvictionPolicy: tc.unhealthyPodEvictionPolicy,
		},
	}

	Strategy.PrepareForCreate(ctx, pdb)
	errs := Strategy.Validate(ctx, pdb)
	if len(errs) != 0 {
		if !tc.expectedValidationErr {
			t.Errorf("Unexpected error validating %v", errs)
		}
		return // no point going further when we have invalid PDB
	}
	if len(errs) == 0 && tc.expectedValidationErr {
		t.Errorf("Expected error validating")
	}
	if !reflect.DeepEqual(pdb.Spec.UnhealthyPodEvictionPolicy, tc.expectedUnhealthyPodEvictionPolicy) {
		t.Errorf("Unexpected UnhealthyPodEvictionPolicy set: expected %v, got %v", tc.expectedUnhealthyPodEvictionPolicy, pdb.Spec.UnhealthyPodEvictionPolicy)
	}
	if tc.disablePDBUnhealthyPodEvictionPolicyFeatureGateAfterCreate {
		defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.PDBUnhealthyPodEvictionPolicy, false)()
	}

	newPdb := &policy.PodDisruptionBudget{
		ObjectMeta: metav1.ObjectMeta{Name: pdb.Name, Namespace: pdb.Namespace},
		Spec:       pdb.Spec,
	}
	if tc.updateUnhealthyPodEvictionPolicy != nil {
		newPdb.Spec.UnhealthyPodEvictionPolicy = tc.updateUnhealthyPodEvictionPolicy
	}

	// Nothing in Spec changes: OK
	Strategy.PrepareForUpdate(ctx, newPdb, pdb)
	errs = Strategy.ValidateUpdate(ctx, newPdb, pdb)

	if len(errs) != 0 {
		if !tc.expectedValidationUpdateErr {
			t.Errorf("Unexpected error updating PodDisruptionBudget %v", errs)
		}
		return // no point going further when we have invalid PDB
	}
	if len(errs) == 0 && tc.expectedValidationUpdateErr {
		t.Errorf("Expected error updating PodDisruptionBudget")
	}
	if !reflect.DeepEqual(newPdb.Spec.UnhealthyPodEvictionPolicy, tc.expectedUpdateUnhealthyPodEvictionPolicy) {
		t.Errorf("Unexpected UnhealthyPodEvictionPolicy set: expected %v, got %v", tc.expectedUpdateUnhealthyPodEvictionPolicy, newPdb.Spec.UnhealthyPodEvictionPolicy)
	}
}

func testPodDisruptionBudgetStrategy(t *testing.T) {
	ctx := genericapirequest.NewDefaultContext()
	if !Strategy.NamespaceScoped() {
		t.Errorf("PodDisruptionBudget must be namespace scoped")
	}
	if Strategy.AllowCreateOnUpdate() {
		t.Errorf("PodDisruptionBudget should not allow create on update")
	}

	validSelector := map[string]string{"a": "b"}
	minAvailable := intstr.FromInt32(3)
	pdb := &policy.PodDisruptionBudget{
		ObjectMeta: metav1.ObjectMeta{Name: "abc", Namespace: metav1.NamespaceDefault},
		Spec: policy.PodDisruptionBudgetSpec{
			MinAvailable: &minAvailable,
			Selector:     &metav1.LabelSelector{MatchLabels: validSelector},
		},
	}

	Strategy.PrepareForCreate(ctx, pdb)
	errs := Strategy.Validate(ctx, pdb)
	if len(errs) != 0 {
		t.Errorf("Unexpected error validating %v", errs)
	}

	newPdb := &policy.PodDisruptionBudget{
		ObjectMeta: metav1.ObjectMeta{Name: pdb.Name, Namespace: pdb.Namespace},
		Spec:       pdb.Spec,
		Status: policy.PodDisruptionBudgetStatus{
			DisruptionsAllowed: 1,
			CurrentHealthy:     3,
			DesiredHealthy:     3,
			ExpectedPods:       3,
		},
	}

	// Nothing in Spec changes: OK
	Strategy.PrepareForUpdate(ctx, newPdb, pdb)
	errs = Strategy.ValidateUpdate(ctx, newPdb, pdb)
	if len(errs) != 0 {
		t.Errorf("Unexpected error updating PodDisruptionBudget.")
	}

	// Changing the selector?  OK
	newPdb.Spec.Selector = &metav1.LabelSelector{MatchLabels: map[string]string{"a": "bar"}}
	Strategy.PrepareForUpdate(ctx, newPdb, pdb)
	errs = Strategy.ValidateUpdate(ctx, newPdb, pdb)
	if len(errs) != 0 {
		t.Errorf("Expected no error on changing selector on poddisruptionbudgets.")
	}
	newPdb.Spec.Selector = pdb.Spec.Selector

	// Changing MinAvailable?  OK
	newMinAvailable := intstr.FromString("28%")
	newPdb.Spec.MinAvailable = &newMinAvailable
	Strategy.PrepareForUpdate(ctx, newPdb, pdb)
	errs = Strategy.ValidateUpdate(ctx, newPdb, pdb)
	if len(errs) != 0 {
		t.Errorf("Expected no error updating MinAvailable on poddisruptionbudgets.")
	}

	// Changing MinAvailable to MaxAvailable? OK
	maxUnavailable := intstr.FromString("28%")
	newPdb.Spec.MaxUnavailable = &maxUnavailable
	newPdb.Spec.MinAvailable = nil
	Strategy.PrepareForUpdate(ctx, newPdb, pdb)
	errs = Strategy.ValidateUpdate(ctx, newPdb, pdb)
	if len(errs) != 0 {
		t.Errorf("Expected no error updating replacing MinAvailable with MaxUnavailable on poddisruptionbudgets.")
	}
}

func TestPodDisruptionBudgetStatusStrategy(t *testing.T) {
	ctx := genericapirequest.NewDefaultContext()
	if !StatusStrategy.NamespaceScoped() {
		t.Errorf("PodDisruptionBudgetStatus must be namespace scoped")
	}
	if StatusStrategy.AllowCreateOnUpdate() {
		t.Errorf("PodDisruptionBudgetStatus should not allow create on update")
	}

	oldMinAvailable := intstr.FromInt32(3)
	newMinAvailable := intstr.FromInt32(2)

	validSelector := map[string]string{"a": "b"}
	oldPdb := &policy.PodDisruptionBudget{
		ObjectMeta: metav1.ObjectMeta{Name: "abc", Namespace: metav1.NamespaceDefault, ResourceVersion: "10"},
		Spec: policy.PodDisruptionBudgetSpec{
			Selector:     &metav1.LabelSelector{MatchLabels: validSelector},
			MinAvailable: &oldMinAvailable,
		},
		Status: policy.PodDisruptionBudgetStatus{
			DisruptionsAllowed: 1,
			CurrentHealthy:     3,
			DesiredHealthy:     3,
			ExpectedPods:       3,
		},
	}
	newPdb := &policy.PodDisruptionBudget{
		ObjectMeta: metav1.ObjectMeta{Name: "abc", Namespace: metav1.NamespaceDefault, ResourceVersion: "9"},
		Spec: policy.PodDisruptionBudgetSpec{
			Selector:     &metav1.LabelSelector{MatchLabels: validSelector},
			MinAvailable: &newMinAvailable,
		},
		Status: policy.PodDisruptionBudgetStatus{
			DisruptionsAllowed: 0,
			CurrentHealthy:     2,
			DesiredHealthy:     3,
			ExpectedPods:       3,
		},
	}
	StatusStrategy.PrepareForUpdate(ctx, newPdb, oldPdb)
	if newPdb.Status.CurrentHealthy != 2 {
		t.Errorf("PodDisruptionBudget status updates should allow change of CurrentHealthy: %v", newPdb.Status.CurrentHealthy)
	}
	if newPdb.Spec.MinAvailable.IntValue() != 3 {
		t.Errorf("PodDisruptionBudget status updates should not clobber spec: %v", newPdb.Spec)
	}
	errs := StatusStrategy.ValidateUpdate(ctx, newPdb, oldPdb)
	if len(errs) != 0 {
		t.Errorf("Unexpected error %v", errs)
	}
}

func TestPodDisruptionBudgetStatusValidationByApiVersion(t *testing.T) {
	testCases := map[string]struct {
		apiVersion string
		validation bool
	}{
		"policy/v1beta1 should not do update validation": {
			apiVersion: "v1beta1",
			validation: false,
		},
		"policy/v1 should do update validation": {
			apiVersion: "v1",
			validation: true,
		},
		"policy/some-version should do update validation": {
			apiVersion: "some-version",
			validation: true,
		},
	}

	for tn, tc := range testCases {
		t.Run(tn, func(t *testing.T) {
			ctx := genericapirequest.WithRequestInfo(genericapirequest.NewDefaultContext(),
				&genericapirequest.RequestInfo{
					APIGroup:   "policy",
					APIVersion: tc.apiVersion,
				})

			oldMaxUnavailable := intstr.FromInt32(2)
			newMaxUnavailable := intstr.FromInt32(3)
			oldPdb := &policy.PodDisruptionBudget{
				ObjectMeta: metav1.ObjectMeta{Name: "abc", Namespace: metav1.NamespaceDefault, ResourceVersion: "10"},
				Spec: policy.PodDisruptionBudgetSpec{
					Selector:       &metav1.LabelSelector{MatchLabels: map[string]string{"a": "b"}},
					MaxUnavailable: &oldMaxUnavailable,
				},
				Status: policy.PodDisruptionBudgetStatus{
					DisruptionsAllowed: 1,
				},
			}
			newPdb := &policy.PodDisruptionBudget{
				ObjectMeta: metav1.ObjectMeta{Name: "abc", Namespace: metav1.NamespaceDefault, ResourceVersion: "9"},
				Spec: policy.PodDisruptionBudgetSpec{
					Selector:     &metav1.LabelSelector{MatchLabels: map[string]string{"a": "b"}},
					MinAvailable: &newMaxUnavailable,
				},
				Status: policy.PodDisruptionBudgetStatus{
					DisruptionsAllowed: -1, // This is not allowed, so should trigger validation error.
				},
			}

			errs := StatusStrategy.ValidateUpdate(ctx, newPdb, oldPdb)
			hasErrors := len(errs) > 0
			if !tc.validation && hasErrors {
				t.Errorf("Validation failed when no validation should happen")
			}
			if tc.validation && !hasErrors {
				t.Errorf("Expected validation errors but didn't get any")
			}
		})
	}
}

func TestDropDisabledFields(t *testing.T) {
	tests := map[string]struct {
		oldSpec                          *policy.PodDisruptionBudgetSpec
		newSpec                          *policy.PodDisruptionBudgetSpec
		expectNewSpec                    *policy.PodDisruptionBudgetSpec
		enableUnhealthyPodEvictionPolicy bool
	}{
		"disabled clears unhealthyPodEvictionPolicy": {
			enableUnhealthyPodEvictionPolicy: false,
			oldSpec:                          nil,
			newSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			expectNewSpec:                    specWithUnhealthyPodEvictionPolicy(nil),
		},
		"disabled does not allow updating unhealthyPodEvictionPolicy": {
			enableUnhealthyPodEvictionPolicy: false,
			oldSpec:                          specWithUnhealthyPodEvictionPolicy(nil),
			newSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			expectNewSpec:                    specWithUnhealthyPodEvictionPolicy(nil),
		},
		"disabled preserves old unhealthyPodEvictionPolicy when both old and new have it": {
			enableUnhealthyPodEvictionPolicy: false,
			oldSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			newSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			expectNewSpec:                    specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
		},
		"disabled allows updating unhealthyPodEvictionPolicy": {
			enableUnhealthyPodEvictionPolicy: false,
			oldSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			newSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.AlwaysAllow)),
			expectNewSpec:                    specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.AlwaysAllow)),
		},
		"enabled preserve unhealthyPodEvictionPolicy": {
			enableUnhealthyPodEvictionPolicy: true,
			oldSpec:                          nil,
			newSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			expectNewSpec:                    specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
		},
		"enabled allows updating unhealthyPodEvictionPolicy": {
			enableUnhealthyPodEvictionPolicy: true,
			oldSpec:                          specWithUnhealthyPodEvictionPolicy(nil),
			newSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			expectNewSpec:                    specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
		},
		"enabled preserve unhealthyPodEvictionPolicy when both old and new have it": {
			enableUnhealthyPodEvictionPolicy: true,
			oldSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			newSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			expectNewSpec:                    specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
		},
		"enabled updates unhealthyPodEvictionPolicy": {
			enableUnhealthyPodEvictionPolicy: true,
			oldSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.IfHealthyBudget)),
			newSpec:                          specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.AlwaysAllow)),
			expectNewSpec:                    specWithUnhealthyPodEvictionPolicy(unhealthyPolicyPtr(policy.AlwaysAllow)),
		},
	}

	for name, tc := range tests {
		t.Run(name, func(t *testing.T) {
			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.PDBUnhealthyPodEvictionPolicy, tc.enableUnhealthyPodEvictionPolicy)()

			oldSpecBefore := tc.oldSpec.DeepCopy()
			dropDisabledFields(tc.newSpec, tc.oldSpec)
			if !reflect.DeepEqual(tc.newSpec, tc.expectNewSpec) {
				t.Error(cmp.Diff(tc.newSpec, tc.expectNewSpec))
			}
			if !reflect.DeepEqual(tc.oldSpec, oldSpecBefore) {
				t.Error(cmp.Diff(tc.oldSpec, oldSpecBefore))
			}
		})
	}
}

func unhealthyPolicyPtr(unhealthyPodEvictionPolicy policy.UnhealthyPodEvictionPolicyType) *policy.UnhealthyPodEvictionPolicyType {
	return &unhealthyPodEvictionPolicy
}

func specWithUnhealthyPodEvictionPolicy(unhealthyPodEvictionPolicy *policy.UnhealthyPodEvictionPolicyType) *policy.PodDisruptionBudgetSpec {
	return &policy.PodDisruptionBudgetSpec{
		UnhealthyPodEvictionPolicy: unhealthyPodEvictionPolicy,
	}
}