/*
Copyright 2017 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 scheduling

import (
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/kubernetes/pkg/apis/core"
)

const (
	// DefaultPriorityWhenNoDefaultClassExists is used to set priority of pods
	// that do not specify any priority class and there is no priority class
	// marked as default.
	DefaultPriorityWhenNoDefaultClassExists = 0
	// HighestUserDefinablePriority is the highest priority for user defined priority classes. Priority values larger than 1 billion are reserved for Kubernetes system use.
	HighestUserDefinablePriority = int32(1000000000)
	// SystemCriticalPriority is the beginning of the range of priority values for critical system components.
	SystemCriticalPriority = 2 * HighestUserDefinablePriority
	// SystemPriorityClassPrefix is the prefix reserved for system priority class names. Other priority
	// classes are not allowed to start with this prefix.
	// NOTE: In order to avoid conflict of names with user-defined priority classes, all the names must
	// start with SystemPriorityClassPrefix.
	SystemPriorityClassPrefix = "system-"
	// SystemClusterCritical is the system priority class name that represents cluster-critical.
	SystemClusterCritical = SystemPriorityClassPrefix + "cluster-critical"
	// SystemNodeCritical is the system priority class name that represents node-critical.
	SystemNodeCritical = SystemPriorityClassPrefix + "node-critical"
)

// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// PriorityClass defines the mapping from a priority class name to the priority
// integer value. The value can be any valid integer.
type PriorityClass struct {
	metav1.TypeMeta
	// Standard object metadata; More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata.
	// +optional
	metav1.ObjectMeta

	// The value of this priority class. This is the actual priority that pods
	// receive when they have the name of this class in their pod spec.
	Value int32

	// globalDefault specifies whether this PriorityClass should be considered as
	// the default priority for pods that do not have any priority class.
	// Only one PriorityClass can be marked as `globalDefault`. However, if more than
	// one PriorityClasses exists with their `globalDefault` field set to true,
	// the smallest value of such global default PriorityClasses will be used as the default priority.
	// +optional
	GlobalDefault bool

	// Description is an arbitrary string that usually provides guidelines on
	// when this priority class should be used.
	// +optional
	Description string

	// PreemptionPolicy it the Policy for preempting pods with lower priority.
	// This field is alpha-level and is only honored by servers that enable the NonPreemptingPriority feature.
	// +optional
	PreemptionPolicy *core.PreemptionPolicy
}

// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// PriorityClassList is a collection of priority classes.
type PriorityClassList struct {
	metav1.TypeMeta
	// Standard list metadata.
	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds
	// +optional
	metav1.ListMeta

	// Items is the list of PriorityClasses.
	Items []PriorityClass
}
