package main

import (
	"log"
	"net/http"

	"github.com/gin-gonic/gin"

	"golang.org/x/sync/errgroup"

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

var (
	sOkay = promauto.NewCounter(prometheus.CounterOpts{
		Name: "http_processed_okay",
		Help: "The number of successful requests",
	})

	sBad = promauto.NewCounter(prometheus.CounterOpts{
		Name: "http_processed_ops_bad",
		Help: "The number of bad requests",
	})

	sError = promauto.NewCounter(prometheus.CounterOpts{
		Name: "http_processed_ops_error",
		Help: "The number of internal error requests",
	})

	sTotal = promauto.NewCounter(prometheus.CounterOpts{
		Name: "http_processed_ops_total",
		Help: "The total number of requests",
	})

	g errgroup.Group
)

func main() {
	r := gin.Default()

	r.Use(func(ctx *gin.Context) {
		ctx.Next()
		switch c := ctx.Writer.Status(); {
		case c >= 200 && c < 300:
			sOkay.Inc()
		case c >= 400 && c < 500:
			sBad.Inc()
		case c >= 500:
			sError.Inc()
		}
		sTotal.Inc()
	})

	r.GET("/ping", func(ctx *gin.Context) {
		ctx.AbortWithStatus(http.StatusBadRequest)
	})

	g.Go(func() error {
		http.Handle("/metrics", promhttp.Handler())
		return http.ListenAndServe(":2112", nil)
	})

	g.Go(func() error {
		return r.Run()
	})

	log.Println(g.Wait())
}