package server

import (
	"strconv"
	"time"

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

var (
	httpInFlight = promauto.NewGauge(prometheus.GaugeOpts{
		Name: "telemt_gateway_http_in_flight",
		Help: "Current requests being served.",
	})
	httpRequests = promauto.NewCounterVec(prometheus.CounterOpts{
		Name: "telemt_gateway_http_requests_total",
		Help: "HTTP requests by status, method, alias, endpoint.",
	}, []string{"code", "method", "alias", "endpoint"})
	httpDuration = promauto.NewHistogramVec(prometheus.HistogramOpts{
		Name:    "telemt_gateway_http_request_duration_seconds",
		Help:    "Request duration in seconds.",
		Buckets: prometheus.DefBuckets,
	}, []string{"method", "alias", "endpoint"})
)

func observeRequest(method, alias, endpoint string, status int, started time.Time) {
	httpInFlight.Dec()
	httpRequests.WithLabelValues(strconv.Itoa(status), method, alias, endpoint).Inc()
	httpDuration.WithLabelValues(method, alias, endpoint).Observe(time.Since(started).Seconds())
}