/*
Copyright 2015 Google Inc. 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 etcd

import (
	"fmt"
	"path"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/fields"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/generic"
	etcdgeneric "github.com/GoogleCloudPlatform/kubernetes/pkg/registry/generic/etcd"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/namespace"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
)

// rest implements a RESTStorage for namespaces against etcd
type REST struct {
	*etcdgeneric.Etcd
	status *etcdgeneric.Etcd
}

// StatusREST implements the REST endpoint for changing the status of a namespace.
type StatusREST struct {
	store *etcdgeneric.Etcd
}

// FinalizeREST implements the REST endpoint for finalizing a namespace.
type FinalizeREST struct {
	store *etcdgeneric.Etcd
}

// NewStorage returns a RESTStorage object that will work against namespaces
func NewStorage(h tools.EtcdHelper) (*REST, *StatusREST, *FinalizeREST) {
	prefix := "/namespaces"
	store := &etcdgeneric.Etcd{
		NewFunc:     func() runtime.Object { return &api.Namespace{} },
		NewListFunc: func() runtime.Object { return &api.NamespaceList{} },
		KeyRootFunc: func(ctx api.Context) string {
			return prefix
		},
		KeyFunc: func(ctx api.Context, name string) (string, error) {
			return path.Join(prefix, name), nil
		},
		ObjectNameFunc: func(obj runtime.Object) (string, error) {
			return obj.(*api.Namespace).Name, nil
		},
		PredicateFunc: func(label labels.Selector, field fields.Selector) generic.Matcher {
			return namespace.MatchNamespace(label, field)
		},
		EndpointName: "namespaces",
		Helper:       h,
	}
	store.CreateStrategy = namespace.Strategy
	store.UpdateStrategy = namespace.Strategy
	store.ReturnDeletedObject = true

	statusStore := *store
	statusStore.UpdateStrategy = namespace.StatusStrategy

	finalizeStore := *store
	finalizeStore.UpdateStrategy = namespace.FinalizeStrategy

	return &REST{Etcd: store, status: &statusStore}, &StatusREST{store: &statusStore}, &FinalizeREST{store: &finalizeStore}
}

// Delete enforces life-cycle rules for namespace termination
func (r *REST) Delete(ctx api.Context, name string, options *api.DeleteOptions) (runtime.Object, error) {
	nsObj, err := r.Get(ctx, name)
	if err != nil {
		return nil, err
	}

	namespace := nsObj.(*api.Namespace)

	// upon first request to delete, we switch the phase to start namespace termination
	if namespace.DeletionTimestamp.IsZero() {
		now := util.Now()
		namespace.DeletionTimestamp = &now
		namespace.Status.Phase = api.NamespaceTerminating
		result, _, err := r.status.Update(ctx, namespace)
		return result, err
	}

	// prior to final deletion, we must ensure that finalizers is empty
	if len(namespace.Spec.Finalizers) != 0 {
		err = fmt.Errorf("Namespace %v termination is in progress, waiting for %v", namespace.Name, namespace.Spec.Finalizers)
		return nil, err
	}
	return r.Etcd.Delete(ctx, name, nil)
}

func (r *StatusREST) New() runtime.Object {
	return r.store.New()
}

// Update alters the status subset of an object.
func (r *StatusREST) Update(ctx api.Context, obj runtime.Object) (runtime.Object, bool, error) {
	return r.store.Update(ctx, obj)
}

func (r *FinalizeREST) New() runtime.Object {
	return r.store.New()
}

// Update alters the status finalizers subset of an object.
func (r *FinalizeREST) Update(ctx api.Context, obj runtime.Object) (runtime.Object, bool, error) {
	return r.store.Update(ctx, obj)
}