package metrics

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

const stateSubsystem = "state"

const (
	healthMetric      = "health"
	versionInfoMetric = "version_info"
)

// HealthStatus of the gate application.
type HealthStatus int32

const (
	HealthStatusUndefined    HealthStatus = 0
	HealthStatusStarting     HealthStatus = 1
	HealthStatusReady        HealthStatus = 2
	HealthStatusShuttingDown HealthStatus = 3
)

type StateMetrics struct {
	healthCheck prometheus.Gauge
	versionInfo *prometheus.GaugeVec
}

func newStateMetrics() *StateMetrics {
	return &StateMetrics{
		healthCheck: mustNewGauge(appMetricsDesc[stateSubsystem][healthMetric]),
		versionInfo: mustNewGaugeVec(appMetricsDesc[stateSubsystem][versionInfoMetric]),
	}
}

func (m *StateMetrics) SetHealth(s HealthStatus) {
	if m == nil {
		return
	}
	m.healthCheck.Set(float64(s))
}

func (m *StateMetrics) SetVersion(ver string) {
	if m == nil {
		return
	}
	m.versionInfo.WithLabelValues(ver).Set(1)
}

func (m *StateMetrics) Describe(desc chan<- *prometheus.Desc) {
	if m == nil {
		return
	}

	m.healthCheck.Describe(desc)
	m.versionInfo.Describe(desc)
}

func (m *StateMetrics) Collect(ch chan<- prometheus.Metric) {
	if m == nil {
		return
	}

	m.healthCheck.Collect(ch)
	m.versionInfo.Collect(ch)
}