/*
Copyright 2016 The Kubernetes Authors All rights reserved.

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 (
	"k8s.io/kubernetes/pkg/api"
	"k8s.io/kubernetes/pkg/api/unversioned"
	unversionedvalidation "k8s.io/kubernetes/pkg/api/unversioned/validation"
	apivalidation "k8s.io/kubernetes/pkg/api/validation"
	"k8s.io/kubernetes/pkg/apis/apps"
	"k8s.io/kubernetes/pkg/labels"
	"k8s.io/kubernetes/pkg/util/validation/field"
)

// ValidatePetSetName can be used to check whether the given PetSet
// name is valid.
// Prefix indicates this name will be used as part of generation, in which case
// trailing dashes are allowed.
func ValidatePetSetName(name string, prefix bool) (bool, string) {
	return apivalidation.NameIsDNSSubdomain(name, prefix)
}

// Validates the given template and ensures that it is in accordance with the desired selector.
func ValidatePodTemplateSpecForPetSet(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 PetSet 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, apivalidation.ValidateLabels(template.Labels, fldPath.Child("labels"))...)
		allErrs = append(allErrs, apivalidation.ValidateAnnotations(template.Annotations, fldPath.Child("annotations"))...)
		allErrs = append(allErrs, apivalidation.ValidatePodSpecificAnnotations(template.Annotations, fldPath.Child("annotations"))...)
	}
	return allErrs
}

// ValidatePetSetSpec tests if required fields in the PetSet spec are set.
func ValidatePetSetSpec(spec *apps.PetSetSpec, 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 not valid for petset."))
		}
	}

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

	return allErrs
}

// ValidatePetSet validates a PetSet.
func ValidatePetSet(petSet *apps.PetSet) field.ErrorList {
	allErrs := apivalidation.ValidateObjectMeta(&petSet.ObjectMeta, true, ValidatePetSetName, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidatePetSetSpec(&petSet.Spec, field.NewPath("spec"))...)
	return allErrs
}

// ValidatePetSetUpdate tests if required fields in the PetSet are set.
func ValidatePetSetUpdate(petSet, oldPetSet *apps.PetSet) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, apivalidation.ValidateObjectMetaUpdate(&petSet.ObjectMeta, &oldPetSet.ObjectMeta, field.NewPath("metadata"))...)
	allErrs = append(allErrs, ValidatePetSetSpec(&petSet.Spec, field.NewPath("spec"))...)
	return allErrs
}

// ValidatePetSetStatusUpdate tests if required fields in the PetSet are set.
func ValidatePetSetStatusUpdate(petSet, oldPetSet *apps.PetSet) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, apivalidation.ValidateObjectMetaUpdate(&petSet.ObjectMeta, &oldPetSet.ObjectMeta, field.NewPath("metadata"))...)
	// TODO: Validate status.
	return allErrs
}