package metrics

import (
	"strconv"
	"time"

	"github.com/prometheus/client_golang/prometheus"
)

const (
	innerRingSubsystem    = "ir"
	innerRingLabelSuccess = "success"
	innerRingLabelType    = "type"
)

// InnerRingServiceMetrics contains metrics collected by inner ring.
type InnerRingServiceMetrics struct {
	epoch         metric[prometheus.Gauge]
	health        metric[prometheus.Gauge]
	eventDuration metric[*prometheus.HistogramVec]
}

// NewInnerRingMetrics returns new instance of metrics collectors for inner ring.
func NewInnerRingMetrics() *InnerRingServiceMetrics {
	var (
		epoch = newGauge(prometheus.GaugeOpts{
			Namespace: namespace,
			Subsystem: innerRingSubsystem,
			Name:      "epoch",
			Help:      "Current epoch as seen by inner-ring node.",
		})
		health = newGauge(prometheus.GaugeOpts{
			Namespace: namespace,
			Subsystem: innerRingSubsystem,
			Name:      "health",
			Help:      "Current inner-ring node state.",
		})
		eventDuration = newHistogramVec(prometheus.HistogramOpts{
			Namespace: namespace,
			Subsystem: innerRingSubsystem,
			Name:      "event_duration_seconds",
			Help:      "Duration of processing of inner-ring events",
		}, []string{innerRingLabelType, innerRingLabelSuccess})
	)

	mustRegister(epoch)
	mustRegister(health)
	mustRegister(eventDuration)

	return &InnerRingServiceMetrics{
		epoch:         epoch,
		health:        health,
		eventDuration: eventDuration,
	}
}

// SetEpoch updates epoch metrics.
func (m InnerRingServiceMetrics) SetEpoch(epoch uint64) {
	m.epoch.value.Set(float64(epoch))
}

// SetHealth updates health metrics.
func (m InnerRingServiceMetrics) SetHealth(s int32) {
	m.health.value.Set(float64(s))
}

func (m InnerRingServiceMetrics) AddEvent(d time.Duration, typ string, success bool) {
	m.eventDuration.value.With(prometheus.Labels{
		innerRingLabelType:    typ,
		innerRingLabelSuccess: strconv.FormatBool(success),
	}).Observe(d.Seconds())
}