package observability

import (
	"context"
	"time"

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

var (
	dependencyUp = promauto.NewGaugeVec(prometheus.GaugeOpts{
		Namespace: "voice_platform", Subsystem: "dependency", Name: "up",
		Help: "Whether the last dependency check succeeded.",
	}, []string{"service", "dependency"})
	dependencyCheckDuration = promauto.NewHistogramVec(prometheus.HistogramOpts{
		Namespace: "voice_platform", Subsystem: "dependency", Name: "check_duration_seconds",
		Help:    "Dependency check duration.",
		Buckets: []float64{0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2},
	}, []string{"service", "dependency"})
)

func InstrumentDependencyCheck(serviceName, dependency string, check func(context.Context) error) func(context.Context) error {
	return func(ctx context.Context) error {
		startedAt := time.Now()
		err := check(ctx)
		dependencyCheckDuration.WithLabelValues(serviceName, dependency).Observe(time.Since(startedAt).Seconds())
		if err != nil {
			dependencyUp.WithLabelValues(serviceName, dependency).Set(0)
			return err
		}
		dependencyUp.WithLabelValues(serviceName, dependency).Set(1)
		return nil
	}
}