/*
Copyright 2014 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 kubelet

import (
	"fmt"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
)

const ConfigSourceAnnotationKey = "kubernetes.io/config.source"
const ConfigMirrorAnnotationKey = "kubernetes.io/config.mirror"
const ConfigFirstSeenAnnotationKey = "kubernetes.io/config.seen"

// PodOperation defines what changes will be made on a pod configuration.
type PodOperation int

const (
	// This is the current pod configuration
	SET PodOperation = iota
	// Pods with the given ids are new to this source
	ADD
	// Pods with the given ids have been removed from this source
	REMOVE
	// Pods with the given ids have been updated in this source
	UPDATE

	// These constants identify the sources of pods
	// Updates from a file
	FileSource = "file"
	// Updates from querying a web page
	HTTPSource = "http"
	// Updates from Kubernetes API Server
	ApiserverSource = "api"
	// Updates from all sources
	AllSource = "*"

	// Used for ConfigMirrorAnnotationKey.
	MirrorType = "mirror"

	NamespaceDefault = api.NamespaceDefault
)

// PodUpdate defines an operation sent on the channel. You can add or remove single services by
// sending an array of size one and Op == ADD|REMOVE (with REMOVE, only the ID is required).
// For setting the state of the system to a given state for this source configuration, set
// Pods as desired and Op to SET, which will reset the system state to that specified in this
// operation for this source channel. To remove all pods, set Pods to empty object and Op to SET.
//
// Additionally, Pods should never be nil - it should always point to an empty slice. While
// functionally similar, this helps our unit tests properly check that the correct PodUpdates
// are generated.
type PodUpdate struct {
	Pods   []*api.Pod
	Op     PodOperation
	Source string
}

// Gets all validated sources from the specified sources.
func GetValidatedSources(sources []string) ([]string, error) {
	validated := make([]string, 0, len(sources))
	for _, source := range sources {
		switch source {
		case AllSource:
			return []string{FileSource, HTTPSource, ApiserverSource}, nil
		case FileSource, HTTPSource, ApiserverSource:
			validated = append(validated, source)
			break
		case "":
			break
		default:
			return []string{}, fmt.Errorf("unknown pod source %q", source)
		}
	}
	return validated, nil
}