package prometheus

import (
	"gitea.pena/PenaSide/verification/internal/repository"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"net/http"
)

type Prometheus struct {
	verificationRepo *repository.VerificationRepository
	metrics          prometheusRegistry
}

type prometheusRegistry struct {
	totalBytes   prometheus.Gauge // Общее количество загруженной памяти
	totalTime    prometheus.Gauge // Общее затраченное время на 1 загрузку
	totalUploads prometheus.Gauge // Количество всего загрузок файлов
}

func NewPrometheus(verificationRepo *repository.VerificationRepository) *Prometheus {
	registry := prometheusRegistry{
		totalBytes: prometheus.NewGauge(prometheus.GaugeOpts{
			Name: "s3_total_uploaded_bytes",
			Help: "Total memory loaded in bytes to S3",
		}),
		totalTime: prometheus.NewGauge(prometheus.GaugeOpts{
			Name: "s3_total_upload_time_ns",
			Help: "Total time spent downloading files to S3",
		}),
		totalUploads: prometheus.NewGauge(prometheus.GaugeOpts{
			Name: "s3_total_upload_count",
			Help: "Number of total file downloads to S3",
		}),
	}

	prometheus.MustRegister(
		registry.totalBytes,
		registry.totalTime,
		registry.totalUploads,
	)

	return &Prometheus{
		verificationRepo: verificationRepo,
		metrics:          registry,
	}
}

func (receiver *Prometheus) Metrics(w http.ResponseWriter, r *http.Request) {
	receiver.updateMetrics()
	handler := promhttp.Handler()

	handler.ServeHTTP(w, r)
}

func (receiver *Prometheus) updateMetrics() {
	receiver.metrics.totalBytes.Set(float64(receiver.verificationRepo.Metrics.TotalBytes))
	receiver.metrics.totalTime.Set(float64(receiver.verificationRepo.Metrics.TotalTime))
	receiver.metrics.totalUploads.Set(float64(receiver.verificationRepo.Metrics.TotalUploads))
}