/*
Copyright 2014 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 ingress

import (
	"fmt"
	"reflect"

	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/util/validation/field"
	genericapirequest "k8s.io/apiserver/pkg/endpoints/request"
	"k8s.io/apiserver/pkg/storage/names"
	"k8s.io/kubernetes/pkg/api"
	"k8s.io/kubernetes/pkg/apis/extensions"
	"k8s.io/kubernetes/pkg/apis/extensions/validation"
	"k8s.io/kubernetes/pkg/genericapiserver/registry/generic"
	"k8s.io/kubernetes/pkg/storage"
)

// ingressStrategy implements verification logic for Replication Ingresss.
type ingressStrategy struct {
	runtime.ObjectTyper
	names.NameGenerator
}

// Strategy is the default logic that applies when creating and updating Replication Ingress objects.
var Strategy = ingressStrategy{api.Scheme, names.SimpleNameGenerator}

// NamespaceScoped returns true because all Ingress' need to be within a namespace.
func (ingressStrategy) NamespaceScoped() bool {
	return true
}

// PrepareForCreate clears the status of an Ingress before creation.
func (ingressStrategy) PrepareForCreate(ctx genericapirequest.Context, obj runtime.Object) {
	ingress := obj.(*extensions.Ingress)
	// create cannot set status
	ingress.Status = extensions.IngressStatus{}

	ingress.Generation = 1
}

// PrepareForUpdate clears fields that are not allowed to be set by end users on update.
func (ingressStrategy) PrepareForUpdate(ctx genericapirequest.Context, obj, old runtime.Object) {
	newIngress := obj.(*extensions.Ingress)
	oldIngress := old.(*extensions.Ingress)
	// Update is not allowed to set status
	newIngress.Status = oldIngress.Status

	// Any changes to the spec increment the generation number, any changes to the
	// status should reflect the generation number of the corresponding object.
	// See metav1.ObjectMeta description for more information on Generation.
	if !reflect.DeepEqual(oldIngress.Spec, newIngress.Spec) {
		newIngress.Generation = oldIngress.Generation + 1
	}

}

// Validate validates a new Ingress.
func (ingressStrategy) Validate(ctx genericapirequest.Context, obj runtime.Object) field.ErrorList {
	ingress := obj.(*extensions.Ingress)
	err := validation.ValidateIngress(ingress)
	return err
}

// Canonicalize normalizes the object after validation.
func (ingressStrategy) Canonicalize(obj runtime.Object) {
}

// AllowCreateOnUpdate is false for Ingress; this means POST is needed to create one.
func (ingressStrategy) AllowCreateOnUpdate() bool {
	return false
}

// ValidateUpdate is the default update validation for an end user.
func (ingressStrategy) ValidateUpdate(ctx genericapirequest.Context, obj, old runtime.Object) field.ErrorList {
	validationErrorList := validation.ValidateIngress(obj.(*extensions.Ingress))
	updateErrorList := validation.ValidateIngressUpdate(obj.(*extensions.Ingress), old.(*extensions.Ingress))
	return append(validationErrorList, updateErrorList...)
}

// AllowUnconditionalUpdate is the default update policy for Ingress objects.
func (ingressStrategy) AllowUnconditionalUpdate() bool {
	return true
}

// IngressToSelectableFields returns a field set that represents the object.
func IngressToSelectableFields(ingress *extensions.Ingress) fields.Set {
	return generic.ObjectMetaFieldsSet(&ingress.ObjectMeta, true)
}

// GetAttrs returns labels and fields of a given object for filtering purposes.
func GetAttrs(obj runtime.Object) (labels.Set, fields.Set, error) {
	ingress, ok := obj.(*extensions.Ingress)
	if !ok {
		return nil, nil, fmt.Errorf("Given object is not an Ingress.")
	}
	return labels.Set(ingress.ObjectMeta.Labels), IngressToSelectableFields(ingress), nil
}

// MatchIngress is the filter used by the generic etcd backend to ingress
// watch events from etcd to clients of the apiserver only interested in specific
// labels/fields.
func MatchIngress(label labels.Selector, field fields.Selector) storage.SelectionPredicate {
	return storage.SelectionPredicate{
		Label:    label,
		Field:    field,
		GetAttrs: GetAttrs,
	}
}

type ingressStatusStrategy struct {
	ingressStrategy
}

var StatusStrategy = ingressStatusStrategy{Strategy}

// PrepareForUpdate clears fields that are not allowed to be set by end users on update of status
func (ingressStatusStrategy) PrepareForUpdate(ctx genericapirequest.Context, obj, old runtime.Object) {
	newIngress := obj.(*extensions.Ingress)
	oldIngress := old.(*extensions.Ingress)
	// status changes are not allowed to update spec
	newIngress.Spec = oldIngress.Spec
}

// ValidateUpdate is the default update validation for an end user updating status
func (ingressStatusStrategy) ValidateUpdate(ctx genericapirequest.Context, obj, old runtime.Object) field.ErrorList {
	return validation.ValidateIngressStatusUpdate(obj.(*extensions.Ingress), old.(*extensions.Ingress))
}
