/*
Copyright 2016 The Kubernetes Authors.
Copyright 2020 Authors of Arktos - file modified.

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 validation

import (
	"fmt"
	"strconv"

	apiequality "k8s.io/apimachinery/pkg/api/equality"
	apimachineryvalidation "k8s.io/apimachinery/pkg/api/validation"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	unversionedvalidation "k8s.io/apimachinery/pkg/apis/meta/v1/validation"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/util/intstr"
	"k8s.io/apimachinery/pkg/util/validation"
	"k8s.io/apimachinery/pkg/util/validation/field"
	"k8s.io/kubernetes/pkg/apis/apps"
	api "k8s.io/kubernetes/pkg/apis/core"
	apivalidation "k8s.io/kubernetes/pkg/apis/core/validation"
)

// ValidateStatefulSetName can be used to check whether the given StatefulSet name is valid.
// Prefix indicates this name will be used as part of generation, in which case
// trailing dashes are allowed.
func ValidateStatefulSetName(name string, prefix bool) []string {
	// TODO: Validate that there's name for the suffix inserted by the pods.
	// Currently this is just "-index". In the future we may allow a user
	// specified list of suffixes and we need  to validate the longest one.
	return apimachineryvalidation.NameIsDNSSubdomain(name, prefix)
}

// ValidatePodTemplateSpecForStatefulSet validates the given template and ensures that it is in accordance with the desired selector.
func ValidatePodTemplateSpecForStatefulSet(template *api.PodTemplateSpec, selector labels.Selector, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	if template == nil {
		allErrs = append(allErrs, field.Required(fldPath, ""))
	} else {
		if !selector.Empty() {
			// Verify that the StatefulSet selector matches the labels in template.
			labels := labels.Set(template.Labels)
			if !selector.Matches(labels) {
				allErrs = append(allErrs, field.Invalid(fldPath.Child("metadata", "labels"), template.Labels, "`selector` does not match template `labels`"))
			}
		}
		// TODO: Add validation for PodSpec, currently this will check volumes, which we know will
		// fail. We should really check that the union of the given volumes and volumeClaims match
		// volume mounts in the containers.
		// allErrs = append(allErrs, apivalidation.ValidatePodTemplateSpec(template, fldPath)...)
		allErrs = append(allErrs, unversionedvalidation.ValidateLabels(template.Labels, fldPath.Child("labels"))...)
		allErrs = append(allErrs, apivalidation.ValidateAnnotations(template.Annotations, fldPath.Child("annotations"))...)
		allErrs = append(allErrs, apivalidation.ValidatePodSpecificAnnotations(template.Annotations, &template.Spec, fldPath.Child("annotations"))...)
	}
	return allErrs
}

// ValidateStatefulSetSpec tests if required fields in the StatefulSet spec are set.
func ValidateStatefulSetSpec(spec *apps.StatefulSetSpec, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	switch spec.PodManagementPolicy {
	case "":
		allErrs = append(allErrs, field.Required(fldPath.Child("podManagementPolicy"), ""))
	case apps.OrderedReadyPodManagement, apps.ParallelPodManagement:
	default:
		allErrs = append(allErrs, field.Invalid(fldPath.Child("podManagementPolicy"), spec.PodManagementPolicy, fmt.Sprintf("must be '%s' or '%s'", apps.OrderedReadyPodManagement, apps.ParallelPodManagement)))
	}

	switch spec.UpdateStrategy.Type {
	case "":
		allErrs = append(allErrs, field.Required(fldPath.Child("updateStrategy"), ""))
	case apps.OnDeleteStatefulSetStrategyType:
		if spec.UpdateStrategy.RollingUpdate != nil {
			allErrs = append(
				allErrs,
				field.Invalid(
					fldPath.Child("updateStrategy").Child("rollingUpdate"),
					spec.UpdateStrategy.RollingUpdate,
					fmt.Sprintf("only allowed for updateStrategy '%s'", apps.RollingUpdateStatefulSetStrategyType)))
		}
	case apps.RollingUpdateStatefulSetStrategyType:
		if spec.UpdateStrategy.RollingUpdate != nil {
			allErrs = append(allErrs,
				apivalidation.ValidateNonnegativeField(
					int64(spec.UpdateStrategy.RollingUpdate.Partition),
					fldPath.Child("updateStrategy").Child("rollingUpdate").Child("partition"))...)
		}
	default:
		allErrs = append(allErrs,
			field.Invalid(fldPath.Child("updateStrategy"), spec.UpdateStrategy,
				fmt.Sprintf("must be '%s' or '%s'",
					apps.RollingUpdateStatefulSetStrategyType,
					apps.OnDeleteStatefulSetStrategyType)))
	}

	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(spec.Replicas), fldPath.Child("replicas"))...)
	if spec.Selector == nil {
		allErrs = append(allErrs, field.Required(fldPath.Child("selector"), ""))
	} else {
		allErrs = append(allErrs, unversionedvalidation.ValidateLabelSelector(spec.Selector, fldPath.Child("selector"))...)
		if len(spec.Selector.MatchLabels)+len(spec.Selector.MatchExpressions) == 0 {
			allErrs = append(allErrs, field.Invalid(fldPath.Child("selector"), spec.Selector, "empty selector is invalid for statefulset"))
		}
	}

	selector, err := metav1.LabelSelectorAsSelector(spec.Selector)
	if err != nil {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("selector"), spec.Selector, ""))
	} else {
		allErrs = append(allErrs, ValidatePodTemplateSpecForStatefulSet(&spec.Template, selector, fldPath.Child("template"))...)
	}

	if spec.Template.Spec.RestartPolicy != api.RestartPolicyAlways {
		allErrs = append(allErrs, field.NotSupported(fldPath.Child("template", "spec", "restartPolicy"), spec.Template.Spec.RestartPolicy, []string{string(api.RestartPolicyAlways)}))
	}
	if spec.Template.Spec.ActiveDeadlineSeconds != nil {
		allErrs = append(allErrs, field.Forbidden(fldPath.Child("template", "spec", "activeDeadlineSeconds"), "activeDeadlineSeconds in StatefulSet is not Supported"))
	}

	return allErrs
}

// ValidateStatefulSet validates a StatefulSet.
func ValidateStatefulSet(statefulSet *apps.StatefulSet) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMeta(&statefulSet.ObjectMeta, true, true, ValidateStatefulSetName, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidateStatefulSetSpec(&statefulSet.Spec, field.NewPath("spec"))...)
	return allErrs
}

// ValidateStatefulSetUpdate tests if required fields in the StatefulSet are set.
func ValidateStatefulSetUpdate(statefulSet, oldStatefulSet *apps.StatefulSet) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMetaUpdate(&statefulSet.ObjectMeta, &oldStatefulSet.ObjectMeta, field.NewPath("metadata"))

	restoreReplicas := statefulSet.Spec.Replicas
	statefulSet.Spec.Replicas = oldStatefulSet.Spec.Replicas

	restoreTemplate := statefulSet.Spec.Template
	statefulSet.Spec.Template = oldStatefulSet.Spec.Template

	restoreStrategy := statefulSet.Spec.UpdateStrategy
	statefulSet.Spec.UpdateStrategy = oldStatefulSet.Spec.UpdateStrategy

	if !apiequality.Semantic.DeepEqual(statefulSet.Spec, oldStatefulSet.Spec) {
		allErrs = append(allErrs, field.Forbidden(field.NewPath("spec"), "updates to statefulset spec for fields other than 'replicas', 'template', and 'updateStrategy' are forbidden"))
	}
	statefulSet.Spec.Replicas = restoreReplicas
	statefulSet.Spec.Template = restoreTemplate
	statefulSet.Spec.UpdateStrategy = restoreStrategy

	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(statefulSet.Spec.Replicas), field.NewPath("spec", "replicas"))...)
	return allErrs
}

// ValidateStatefulSetStatus validates a StatefulSetStatus.
func ValidateStatefulSetStatus(status *apps.StatefulSetStatus, fieldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.Replicas), fieldPath.Child("replicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.ReadyReplicas), fieldPath.Child("readyReplicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.CurrentReplicas), fieldPath.Child("currentReplicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.UpdatedReplicas), fieldPath.Child("updatedReplicas"))...)
	if status.ObservedGeneration != nil {
		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(*status.ObservedGeneration), fieldPath.Child("observedGeneration"))...)
	}
	if status.CollisionCount != nil {
		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(*status.CollisionCount), fieldPath.Child("collisionCount"))...)
	}

	msg := "cannot be greater than status.replicas"
	if status.ReadyReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fieldPath.Child("readyReplicas"), status.ReadyReplicas, msg))
	}
	if status.CurrentReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fieldPath.Child("currentReplicas"), status.CurrentReplicas, msg))
	}
	if status.UpdatedReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fieldPath.Child("updatedReplicas"), status.UpdatedReplicas, msg))
	}

	return allErrs
}

// ValidateStatefulSetStatusUpdate tests if required fields in the StatefulSet are set.
func ValidateStatefulSetStatusUpdate(statefulSet, oldStatefulSet *apps.StatefulSet) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, ValidateStatefulSetStatus(&statefulSet.Status, field.NewPath("status"))...)
	allErrs = append(allErrs, apivalidation.ValidateObjectMetaUpdate(&statefulSet.ObjectMeta, &oldStatefulSet.ObjectMeta, field.NewPath("metadata"))...)
	// TODO: Validate status.
	if apivalidation.IsDecremented(statefulSet.Status.CollisionCount, oldStatefulSet.Status.CollisionCount) {
		value := int32(0)
		if statefulSet.Status.CollisionCount != nil {
			value = *statefulSet.Status.CollisionCount
		}
		allErrs = append(allErrs, field.Invalid(field.NewPath("status").Child("collisionCount"), value, "cannot be decremented"))
	}
	return allErrs
}

// ValidateControllerRevisionName can be used to check whether the given ControllerRevision name is valid.
// Prefix indicates this name will be used as part of generation, in which case
// trailing dashes are allowed.
var ValidateControllerRevisionName = apimachineryvalidation.NameIsDNSSubdomain

// ValidateControllerRevision collects errors for the fields of state and returns those errors as an ErrorList. If the
// returned list is empty, state is valid. Validation is performed to ensure that state is a valid ObjectMeta, its name
// is valid, and that it doesn't exceed the MaxControllerRevisionSize.
func ValidateControllerRevision(revision *apps.ControllerRevision) field.ErrorList {
	errs := field.ErrorList{}

	errs = append(errs, apivalidation.ValidateObjectMeta(&revision.ObjectMeta, true, true, ValidateControllerRevisionName, field.NewPath("metadata"))...)
	if revision.Data == nil {
		errs = append(errs, field.Required(field.NewPath("data"), "data is mandatory"))
	}
	errs = append(errs, apivalidation.ValidateNonnegativeField(revision.Revision, field.NewPath("revision"))...)
	return errs
}

// ValidateControllerRevisionUpdate collects errors pertaining to the mutation of an ControllerRevision Object. If the
// returned ErrorList is empty the update operation is valid. Any mutation to the ControllerRevision's Data or Revision
// is considered to be invalid.
func ValidateControllerRevisionUpdate(newHistory, oldHistory *apps.ControllerRevision) field.ErrorList {
	errs := field.ErrorList{}

	errs = append(errs, apivalidation.ValidateObjectMetaUpdate(&newHistory.ObjectMeta, &oldHistory.ObjectMeta, field.NewPath("metadata"))...)
	errs = append(errs, ValidateControllerRevision(newHistory)...)
	errs = append(errs, apivalidation.ValidateImmutableField(newHistory.Data, oldHistory.Data, field.NewPath("data"))...)
	return errs
}

// ValidateDaemonSet tests if required fields in the DaemonSet are set.
func ValidateDaemonSet(ds *apps.DaemonSet) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMeta(&ds.ObjectMeta, true, true, ValidateDaemonSetName, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidateDaemonSetSpec(&ds.Spec, field.NewPath("spec"))...)
	return allErrs
}

// ValidateDaemonSetUpdate tests if required fields in the DaemonSet are set.
func ValidateDaemonSetUpdate(ds, oldDS *apps.DaemonSet) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMetaUpdate(&ds.ObjectMeta, &oldDS.ObjectMeta, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidateDaemonSetSpecUpdate(&ds.Spec, &oldDS.Spec, field.NewPath("spec"))...)
	allErrs = append(allErrs, ValidateDaemonSetSpec(&ds.Spec, field.NewPath("spec"))...)
	return allErrs
}

func ValidateDaemonSetSpecUpdate(newSpec, oldSpec *apps.DaemonSetSpec, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	// TemplateGeneration shouldn't be decremented
	if newSpec.TemplateGeneration < oldSpec.TemplateGeneration {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("templateGeneration"), newSpec.TemplateGeneration, "must not be decremented"))
	}

	// TemplateGeneration should be increased when and only when template is changed
	templateUpdated := !apiequality.Semantic.DeepEqual(newSpec.Template, oldSpec.Template)
	if newSpec.TemplateGeneration == oldSpec.TemplateGeneration && templateUpdated {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("templateGeneration"), newSpec.TemplateGeneration, "must be incremented upon template update"))
	} else if newSpec.TemplateGeneration > oldSpec.TemplateGeneration && !templateUpdated {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("templateGeneration"), newSpec.TemplateGeneration, "must not be incremented without template update"))
	}

	return allErrs
}

// validateDaemonSetStatus validates a DaemonSetStatus
func validateDaemonSetStatus(status *apps.DaemonSetStatus, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.CurrentNumberScheduled), fldPath.Child("currentNumberScheduled"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.NumberMisscheduled), fldPath.Child("numberMisscheduled"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.DesiredNumberScheduled), fldPath.Child("desiredNumberScheduled"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.NumberReady), fldPath.Child("numberReady"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(status.ObservedGeneration, fldPath.Child("observedGeneration"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.UpdatedNumberScheduled), fldPath.Child("updatedNumberScheduled"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.NumberAvailable), fldPath.Child("numberAvailable"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.NumberUnavailable), fldPath.Child("numberUnavailable"))...)
	if status.CollisionCount != nil {
		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(*status.CollisionCount), fldPath.Child("collisionCount"))...)
	}
	return allErrs
}

// ValidateDaemonSetStatusUpdate validates tests if required fields in the DaemonSet Status section
func ValidateDaemonSetStatusUpdate(ds, oldDS *apps.DaemonSet) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMetaUpdate(&ds.ObjectMeta, &oldDS.ObjectMeta, field.NewPath("metadata"))
	allErrs = append(allErrs, validateDaemonSetStatus(&ds.Status, field.NewPath("status"))...)
	if apivalidation.IsDecremented(ds.Status.CollisionCount, oldDS.Status.CollisionCount) {
		value := int32(0)
		if ds.Status.CollisionCount != nil {
			value = *ds.Status.CollisionCount
		}
		allErrs = append(allErrs, field.Invalid(field.NewPath("status").Child("collisionCount"), value, "cannot be decremented"))
	}
	return allErrs
}

// ValidateDaemonSetSpec tests if required fields in the DaemonSetSpec are set.
func ValidateDaemonSetSpec(spec *apps.DaemonSetSpec, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	allErrs = append(allErrs, unversionedvalidation.ValidateLabelSelector(spec.Selector, fldPath.Child("selector"))...)

	selector, err := metav1.LabelSelectorAsSelector(spec.Selector)
	if err == nil && !selector.Matches(labels.Set(spec.Template.Labels)) {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("template", "metadata", "labels"), spec.Template.Labels, "`selector` does not match template `labels`"))
	}
	if spec.Selector != nil && len(spec.Selector.MatchLabels)+len(spec.Selector.MatchExpressions) == 0 {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("selector"), spec.Selector, "empty selector is invalid for daemonset"))
	}

	allErrs = append(allErrs, apivalidation.ValidatePodTemplateSpec(&spec.Template, fldPath.Child("template"))...)
	// Daemons typically run on more than one node, so mark Read-Write persistent disks as invalid.
	allErrs = append(allErrs, apivalidation.ValidateReadOnlyPersistentDisks(spec.Template.Spec.Volumes, fldPath.Child("template", "spec", "volumes"))...)
	// RestartPolicy has already been first-order validated as per ValidatePodTemplateSpec().
	if spec.Template.Spec.RestartPolicy != api.RestartPolicyAlways {
		allErrs = append(allErrs, field.NotSupported(fldPath.Child("template", "spec", "restartPolicy"), spec.Template.Spec.RestartPolicy, []string{string(api.RestartPolicyAlways)}))
	}
	if spec.Template.Spec.ActiveDeadlineSeconds != nil {
		allErrs = append(allErrs, field.Forbidden(fldPath.Child("template", "spec", "activeDeadlineSeconds"), "activeDeadlineSeconds in DaemonSet is not Supported"))
	}
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(spec.MinReadySeconds), fldPath.Child("minReadySeconds"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(spec.TemplateGeneration), fldPath.Child("templateGeneration"))...)

	allErrs = append(allErrs, ValidateDaemonSetUpdateStrategy(&spec.UpdateStrategy, fldPath.Child("updateStrategy"))...)
	if spec.RevisionHistoryLimit != nil {
		// zero is a valid RevisionHistoryLimit
		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(*spec.RevisionHistoryLimit), fldPath.Child("revisionHistoryLimit"))...)
	}
	return allErrs
}

func ValidateRollingUpdateDaemonSet(rollingUpdate *apps.RollingUpdateDaemonSet, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, ValidatePositiveIntOrPercent(rollingUpdate.MaxUnavailable, fldPath.Child("maxUnavailable"))...)
	if getIntOrPercentValue(rollingUpdate.MaxUnavailable) == 0 {
		// MaxUnavailable cannot be 0.
		allErrs = append(allErrs, field.Invalid(fldPath.Child("maxUnavailable"), rollingUpdate.MaxUnavailable, "cannot be 0"))
	}
	// Validate that MaxUnavailable is not more than 100%.
	allErrs = append(allErrs, IsNotMoreThan100Percent(rollingUpdate.MaxUnavailable, fldPath.Child("maxUnavailable"))...)
	return allErrs
}

func ValidateDaemonSetUpdateStrategy(strategy *apps.DaemonSetUpdateStrategy, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	switch strategy.Type {
	case apps.OnDeleteDaemonSetStrategyType:
	case apps.RollingUpdateDaemonSetStrategyType:
		// Make sure RollingUpdate field isn't nil.
		if strategy.RollingUpdate == nil {
			allErrs = append(allErrs, field.Required(fldPath.Child("rollingUpdate"), ""))
			return allErrs
		}
		allErrs = append(allErrs, ValidateRollingUpdateDaemonSet(strategy.RollingUpdate, fldPath.Child("rollingUpdate"))...)
	default:
		validValues := []string{string(apps.RollingUpdateDaemonSetStrategyType), string(apps.OnDeleteDaemonSetStrategyType)}
		allErrs = append(allErrs, field.NotSupported(fldPath, strategy, validValues))
	}
	return allErrs
}

// ValidateDaemonSetName can be used to check whether the given daemon set name is valid.
// Prefix indicates this name will be used as part of generation, in which case
// trailing dashes are allowed.
var ValidateDaemonSetName = apimachineryvalidation.NameIsDNSSubdomain

// ValidateDeploymentName validates that the given name can be used as a deployment name.
var ValidateDeploymentName = apimachineryvalidation.NameIsDNSSubdomain

func ValidatePositiveIntOrPercent(intOrPercent intstr.IntOrString, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	switch intOrPercent.Type {
	case intstr.String:
		for _, msg := range validation.IsValidPercent(intOrPercent.StrVal) {
			allErrs = append(allErrs, field.Invalid(fldPath, intOrPercent, msg))
		}
	case intstr.Int:
		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(intOrPercent.IntValue()), fldPath)...)
	default:
		allErrs = append(allErrs, field.Invalid(fldPath, intOrPercent, "must be an integer or percentage (e.g '5%%')"))
	}
	return allErrs
}

func getPercentValue(intOrStringValue intstr.IntOrString) (int, bool) {
	if intOrStringValue.Type != intstr.String {
		return 0, false
	}
	if len(validation.IsValidPercent(intOrStringValue.StrVal)) != 0 {
		return 0, false
	}
	value, _ := strconv.Atoi(intOrStringValue.StrVal[:len(intOrStringValue.StrVal)-1])
	return value, true
}

func getIntOrPercentValue(intOrStringValue intstr.IntOrString) int {
	value, isPercent := getPercentValue(intOrStringValue)
	if isPercent {
		return value
	}
	return intOrStringValue.IntValue()
}

func IsNotMoreThan100Percent(intOrStringValue intstr.IntOrString, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	value, isPercent := getPercentValue(intOrStringValue)
	if !isPercent || value <= 100 {
		return nil
	}
	allErrs = append(allErrs, field.Invalid(fldPath, intOrStringValue, "must not be greater than 100%"))
	return allErrs
}

func ValidateRollingUpdateDeployment(rollingUpdate *apps.RollingUpdateDeployment, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, ValidatePositiveIntOrPercent(rollingUpdate.MaxUnavailable, fldPath.Child("maxUnavailable"))...)
	allErrs = append(allErrs, ValidatePositiveIntOrPercent(rollingUpdate.MaxSurge, fldPath.Child("maxSurge"))...)
	if getIntOrPercentValue(rollingUpdate.MaxUnavailable) == 0 && getIntOrPercentValue(rollingUpdate.MaxSurge) == 0 {
		// Both MaxSurge and MaxUnavailable cannot be zero.
		allErrs = append(allErrs, field.Invalid(fldPath.Child("maxUnavailable"), rollingUpdate.MaxUnavailable, "may not be 0 when `maxSurge` is 0"))
	}
	// Validate that MaxUnavailable is not more than 100%.
	allErrs = append(allErrs, IsNotMoreThan100Percent(rollingUpdate.MaxUnavailable, fldPath.Child("maxUnavailable"))...)
	return allErrs
}

func ValidateDeploymentStrategy(strategy *apps.DeploymentStrategy, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	switch strategy.Type {
	case apps.RecreateDeploymentStrategyType:
		if strategy.RollingUpdate != nil {
			allErrs = append(allErrs, field.Forbidden(fldPath.Child("rollingUpdate"), "may not be specified when strategy `type` is '"+string(apps.RecreateDeploymentStrategyType+"'")))
		}
	case apps.RollingUpdateDeploymentStrategyType:
		// This should never happen since it's set and checked in defaults.go
		if strategy.RollingUpdate == nil {
			allErrs = append(allErrs, field.Required(fldPath.Child("rollingUpdate"), "this should be defaulted and never be nil"))
		} else {
			allErrs = append(allErrs, ValidateRollingUpdateDeployment(strategy.RollingUpdate, fldPath.Child("rollingUpdate"))...)
		}
	default:
		validValues := []string{string(apps.RecreateDeploymentStrategyType), string(apps.RollingUpdateDeploymentStrategyType)}
		allErrs = append(allErrs, field.NotSupported(fldPath, strategy, validValues))
	}
	return allErrs
}

func ValidateRollback(rollback *apps.RollbackConfig, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	v := rollback.Revision
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(v), fldPath.Child("version"))...)
	return allErrs
}

// ValidateDeploymentSpec validates given deployment spec.
func ValidateDeploymentSpec(spec *apps.DeploymentSpec, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(spec.Replicas), fldPath.Child("replicas"))...)

	if spec.Selector == nil {
		allErrs = append(allErrs, field.Required(fldPath.Child("selector"), ""))
	} else {
		allErrs = append(allErrs, unversionedvalidation.ValidateLabelSelector(spec.Selector, fldPath.Child("selector"))...)
		if len(spec.Selector.MatchLabels)+len(spec.Selector.MatchExpressions) == 0 {
			allErrs = append(allErrs, field.Invalid(fldPath.Child("selector"), spec.Selector, "empty selector is invalid for deployment"))
		}
	}

	selector, err := metav1.LabelSelectorAsSelector(spec.Selector)
	if err != nil {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("selector"), spec.Selector, "invalid label selector"))
	} else {
		allErrs = append(allErrs, ValidatePodTemplateSpecForReplicaSet(&spec.Template, selector, spec.Replicas, fldPath.Child("template"))...)
	}

	allErrs = append(allErrs, ValidateDeploymentStrategy(&spec.Strategy, fldPath.Child("strategy"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(spec.MinReadySeconds), fldPath.Child("minReadySeconds"))...)
	if spec.RevisionHistoryLimit != nil {
		// zero is a valid RevisionHistoryLimit
		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(*spec.RevisionHistoryLimit), fldPath.Child("revisionHistoryLimit"))...)
	}
	if spec.RollbackTo != nil {
		allErrs = append(allErrs, ValidateRollback(spec.RollbackTo, fldPath.Child("rollback"))...)
	}
	if spec.ProgressDeadlineSeconds != nil {
		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(*spec.ProgressDeadlineSeconds), fldPath.Child("progressDeadlineSeconds"))...)
		if *spec.ProgressDeadlineSeconds <= spec.MinReadySeconds {
			allErrs = append(allErrs, field.Invalid(fldPath.Child("progressDeadlineSeconds"), spec.ProgressDeadlineSeconds, "must be greater than minReadySeconds"))
		}
	}
	return allErrs
}

// ValidateDeploymentStatus validates given deployment status.
func ValidateDeploymentStatus(status *apps.DeploymentStatus, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(status.ObservedGeneration, fldPath.Child("observedGeneration"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.Replicas), fldPath.Child("replicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.UpdatedReplicas), fldPath.Child("updatedReplicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.ReadyReplicas), fldPath.Child("readyReplicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.AvailableReplicas), fldPath.Child("availableReplicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.UnavailableReplicas), fldPath.Child("unavailableReplicas"))...)
	if status.CollisionCount != nil {
		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(*status.CollisionCount), fldPath.Child("collisionCount"))...)
	}
	msg := "cannot be greater than status.replicas"
	if status.UpdatedReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("updatedReplicas"), status.UpdatedReplicas, msg))
	}
	if status.ReadyReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("readyReplicas"), status.ReadyReplicas, msg))
	}
	if status.AvailableReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("availableReplicas"), status.AvailableReplicas, msg))
	}
	if status.AvailableReplicas > status.ReadyReplicas {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("availableReplicas"), status.AvailableReplicas, "cannot be greater than readyReplicas"))
	}
	return allErrs
}

func ValidateDeploymentUpdate(update, old *apps.Deployment) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMetaUpdate(&update.ObjectMeta, &old.ObjectMeta, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidateDeploymentSpec(&update.Spec, field.NewPath("spec"))...)
	return allErrs
}

func ValidateDeploymentStatusUpdate(update, old *apps.Deployment) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMetaUpdate(&update.ObjectMeta, &old.ObjectMeta, field.NewPath("metadata"))
	fldPath := field.NewPath("status")
	allErrs = append(allErrs, ValidateDeploymentStatus(&update.Status, fldPath)...)
	if apivalidation.IsDecremented(update.Status.CollisionCount, old.Status.CollisionCount) {
		value := int32(0)
		if update.Status.CollisionCount != nil {
			value = *update.Status.CollisionCount
		}
		allErrs = append(allErrs, field.Invalid(fldPath.Child("collisionCount"), value, "cannot be decremented"))
	}
	return allErrs
}

func ValidateDeployment(obj *apps.Deployment) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMeta(&obj.ObjectMeta, true, true, ValidateDeploymentName, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidateDeploymentSpec(&obj.Spec, field.NewPath("spec"))...)
	return allErrs
}

func ValidateDeploymentRollback(obj *apps.DeploymentRollback) field.ErrorList {
	allErrs := apivalidation.ValidateAnnotations(obj.UpdatedAnnotations, field.NewPath("updatedAnnotations"))
	if len(obj.Name) == 0 {
		allErrs = append(allErrs, field.Required(field.NewPath("name"), "name is required"))
	}
	allErrs = append(allErrs, ValidateRollback(&obj.RollbackTo, field.NewPath("rollback"))...)
	return allErrs
}

// ValidateReplicaSetName can be used to check whether the given ReplicaSet
// name is valid.
// Prefix indicates this name will be used as part of generation, in which case
// trailing dashes are allowed.
var ValidateReplicaSetName = apimachineryvalidation.NameIsDNSSubdomain

// ValidateReplicaSet tests if required fields in the ReplicaSet are set.
func ValidateReplicaSet(rs *apps.ReplicaSet) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMeta(&rs.ObjectMeta, true, true, ValidateReplicaSetName, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidateReplicaSetSpec(&rs.Spec, field.NewPath("spec"))...)
	return allErrs
}

// ValidateReplicaSetUpdate tests if required fields in the ReplicaSet are set.
func ValidateReplicaSetUpdate(rs, oldRs *apps.ReplicaSet) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, apivalidation.ValidateObjectMetaUpdate(&rs.ObjectMeta, &oldRs.ObjectMeta, field.NewPath("metadata"))...)
	allErrs = append(allErrs, ValidateReplicaSetSpec(&rs.Spec, field.NewPath("spec"))...)
	return allErrs
}

// ValidateReplicaSetStatusUpdate tests if required fields in the ReplicaSet are set.
func ValidateReplicaSetStatusUpdate(rs, oldRs *apps.ReplicaSet) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, apivalidation.ValidateObjectMetaUpdate(&rs.ObjectMeta, &oldRs.ObjectMeta, field.NewPath("metadata"))...)
	allErrs = append(allErrs, ValidateReplicaSetStatus(rs.Status, field.NewPath("status"))...)
	return allErrs
}

func ValidateReplicaSetStatus(status apps.ReplicaSetStatus, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.Replicas), fldPath.Child("replicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.FullyLabeledReplicas), fldPath.Child("fullyLabeledReplicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.ReadyReplicas), fldPath.Child("readyReplicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.AvailableReplicas), fldPath.Child("availableReplicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(status.ObservedGeneration), fldPath.Child("observedGeneration"))...)
	msg := "cannot be greater than status.replicas"
	if status.FullyLabeledReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("fullyLabeledReplicas"), status.FullyLabeledReplicas, msg))
	}
	if status.ReadyReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("readyReplicas"), status.ReadyReplicas, msg))
	}
	if status.AvailableReplicas > status.Replicas {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("availableReplicas"), status.AvailableReplicas, msg))
	}
	if status.AvailableReplicas > status.ReadyReplicas {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("availableReplicas"), status.AvailableReplicas, "cannot be greater than readyReplicas"))
	}
	return allErrs
}

// ValidateReplicaSetSpec tests if required fields in the ReplicaSet spec are set.
func ValidateReplicaSetSpec(spec *apps.ReplicaSetSpec, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(spec.Replicas), fldPath.Child("replicas"))...)
	allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(spec.MinReadySeconds), fldPath.Child("minReadySeconds"))...)

	if spec.Selector == nil {
		allErrs = append(allErrs, field.Required(fldPath.Child("selector"), ""))
	} else {
		allErrs = append(allErrs, unversionedvalidation.ValidateLabelSelector(spec.Selector, fldPath.Child("selector"))...)
		if len(spec.Selector.MatchLabels)+len(spec.Selector.MatchExpressions) == 0 {
			allErrs = append(allErrs, field.Invalid(fldPath.Child("selector"), spec.Selector, "empty selector is invalid for deployment"))
		}
	}

	selector, err := metav1.LabelSelectorAsSelector(spec.Selector)
	if err != nil {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("selector"), spec.Selector, "invalid label selector"))
	} else {
		allErrs = append(allErrs, ValidatePodTemplateSpecForReplicaSet(&spec.Template, selector, spec.Replicas, fldPath.Child("template"))...)
	}
	return allErrs
}

// ValidatePodTemplateSpecForReplicaSet validates the given template and ensures that it is in accordance with the desired selector and replicas.
func ValidatePodTemplateSpecForReplicaSet(template *api.PodTemplateSpec, selector labels.Selector, replicas int32, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	if template == nil {
		allErrs = append(allErrs, field.Required(fldPath, ""))
	} else {
		if !selector.Empty() {
			// Verify that the ReplicaSet selector matches the labels in template.
			labels := labels.Set(template.Labels)
			if !selector.Matches(labels) {
				allErrs = append(allErrs, field.Invalid(fldPath.Child("metadata", "labels"), template.Labels, "`selector` does not match template `labels`"))
			}
		}
		allErrs = append(allErrs, apivalidation.ValidatePodTemplateSpec(template, fldPath)...)
		if replicas > 1 {
			allErrs = append(allErrs, apivalidation.ValidateReadOnlyPersistentDisks(template.Spec.Volumes, fldPath.Child("spec", "volumes"))...)
		}
		// RestartPolicy has already been first-order validated as per ValidatePodTemplateSpec().
		if template.Spec.RestartPolicy != api.RestartPolicyAlways {
			allErrs = append(allErrs, field.NotSupported(fldPath.Child("spec", "restartPolicy"), template.Spec.RestartPolicy, []string{string(api.RestartPolicyAlways)}))
		}
		if template.Spec.ActiveDeadlineSeconds != nil {
			allErrs = append(allErrs, field.Forbidden(fldPath.Child("spec", "activeDeadlineSeconds"), "activeDeadlineSeconds in ReplicaSet is not Supported"))
		}
	}
	return allErrs
}
