/*
Copyright 2019 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 framework

import (
	"fmt"
	"github.com/blang/semver"
	"github.com/prometheus/client_golang/prometheus"
	"sync"
)

// KubeOpts is superset struct for prometheus.Opts. The prometheus Opts structure
// is purposefully not embedded here because that would change struct initialization
// in the manner which people are currently accustomed.
//
// Name must be set to a non-empty string. DeprecatedVersion is defined only
// if the metric for which this options applies is, in fact, deprecated.
type KubeOpts struct {
	Namespace         string
	Subsystem         string
	Name              string
	Help              string
	ConstLabels       prometheus.Labels
	DeprecatedVersion *semver.Version
	deprecateOnce     sync.Once
	annotateOnce      sync.Once
	StabilityLevel    StabilityLevel
}

type StabilityLevel string

const (
	ALPHA  StabilityLevel = "ALPHA"
	STABLE StabilityLevel = "STABLE"
)

type CounterOpts KubeOpts

// Modify help description on the metric description.
func (o *CounterOpts) markDeprecated() {
	o.deprecateOnce.Do(func() {
		o.Help = fmt.Sprintf("(Deprecated since %v) %v", o.DeprecatedVersion, o.Help)
	})
}

// annotateStabilityLevel annotates help description on the metric description with the stability level
// of the metric
func (o *CounterOpts) annotateStabilityLevel() {
	o.annotateOnce.Do(func() {
		o.Help = fmt.Sprintf("[%v] %v", o.StabilityLevel, o.Help)
	})
}

// convenience function to allow easy transformation to the prometheus
// counterpart. This will do more once we have a proper label abstraction
func (o *CounterOpts) toPromCounterOpts() prometheus.CounterOpts {
	return prometheus.CounterOpts{
		Namespace:   o.Namespace,
		Subsystem:   o.Subsystem,
		Name:        o.Name,
		Help:        o.Help,
		ConstLabels: o.ConstLabels,
	}
}