/*
Copyright 2014 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 event

import (
	"fmt"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/validation"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/generic"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
)

// REST adapts an event registry into apiserver's RESTStorage model.
type REST struct {
	registry generic.Registry
}

// NewREST returns a new REST. You must use a registry created by
// NewEtcdRegistry unless you're testing.
func NewREST(registry generic.Registry) *REST {
	return &REST{
		registry: registry,
	}
}

func (rs *REST) Create(ctx api.Context, obj runtime.Object) (runtime.Object, error) {
	event, ok := obj.(*api.Event)
	if !ok {
		return nil, fmt.Errorf("invalid object type")
	}
	if api.NamespaceValue(ctx) != "" {
		if !api.ValidNamespace(ctx, &event.ObjectMeta) {
			return nil, errors.NewConflict("event", event.Namespace, fmt.Errorf("event.namespace does not match the provided context"))
		}
	}
	if errs := validation.ValidateEvent(event); len(errs) > 0 {
		return nil, errors.NewInvalid("event", event.Name, errs)
	}
	api.FillObjectMetaSystemFields(ctx, &event.ObjectMeta)

	err := rs.registry.CreateWithName(ctx, event.Name, event)
	if err != nil {
		return nil, err
	}
	return rs.registry.Get(ctx, event.Name)
}

// Update replaces an existing Event instance in storage.registry, with the given instance.
func (rs *REST) Update(ctx api.Context, obj runtime.Object) (runtime.Object, bool, error) {
	event, ok := obj.(*api.Event)
	if !ok {
		return nil, false, fmt.Errorf("not an event object: %#v", obj)
	}
	if api.NamespaceValue(ctx) != "" {
		if !api.ValidNamespace(ctx, &event.ObjectMeta) {
			return nil, false, errors.NewConflict("event", event.Namespace, fmt.Errorf("event.namespace does not match the provided context"))
		}
	}
	if errs := validation.ValidateEvent(event); len(errs) > 0 {
		return nil, false, errors.NewInvalid("event", event.Name, errs)
	}
	api.FillObjectMetaSystemFields(ctx, &event.ObjectMeta)

	err := rs.registry.UpdateWithName(ctx, event.Name, event)
	if err != nil {
		return nil, false, err
	}
	out, err := rs.registry.Get(ctx, event.Name)
	return out, false, err
}

func (rs *REST) Delete(ctx api.Context, name string) (runtime.Object, error) {
	obj, err := rs.registry.Get(ctx, name)
	if err != nil {
		return nil, err
	}
	_, ok := obj.(*api.Event)
	if !ok {
		return nil, fmt.Errorf("invalid object type")
	}
	return rs.registry.Delete(ctx, name)
}

func (rs *REST) Get(ctx api.Context, id string) (runtime.Object, error) {
	obj, err := rs.registry.Get(ctx, id)
	if err != nil {
		return nil, err
	}
	event, ok := obj.(*api.Event)
	if !ok {
		return nil, fmt.Errorf("invalid object type")
	}
	return event, err
}

func (rs *REST) getAttrs(obj runtime.Object) (objLabels, objFields labels.Set, err error) {
	event, ok := obj.(*api.Event)
	if !ok {
		return nil, nil, fmt.Errorf("invalid object type")
	}
	// TODO: internal version leaks through here. This should be versioned.
	return labels.Set{}, labels.Set{
		"involvedObject.kind":            event.InvolvedObject.Kind,
		"involvedObject.namespace":       event.InvolvedObject.Namespace,
		"involvedObject.name":            event.InvolvedObject.Name,
		"involvedObject.uid":             string(event.InvolvedObject.UID),
		"involvedObject.apiVersion":      event.InvolvedObject.APIVersion,
		"involvedObject.resourceVersion": fmt.Sprintf("%s", event.InvolvedObject.ResourceVersion),
		"involvedObject.fieldPath":       event.InvolvedObject.FieldPath,
		"reason":                         event.Reason,
		"source":                         event.Source.Component,
	}, nil
}

func (rs *REST) List(ctx api.Context, label, field labels.Selector) (runtime.Object, error) {
	return rs.registry.List(ctx, &generic.SelectionPredicate{label, field, rs.getAttrs})
}

// Watch returns Events events via a watch.Interface.
// It implements apiserver.ResourceWatcher.
func (rs *REST) Watch(ctx api.Context, label, field labels.Selector, resourceVersion string) (watch.Interface, error) {
	return rs.registry.Watch(ctx, &generic.SelectionPredicate{label, field, rs.getAttrs}, resourceVersion)
}

// New returns a new api.Event
func (*REST) New() runtime.Object {
	return &api.Event{}
}

func (*REST) NewList() runtime.Object {
	return &api.EventList{}
}