package middlewares

import (
	"strconv"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/prometheus/client_golang/prometheus"
)

var (
	httpRequests = prometheus.NewCounterVec(prometheus.CounterOpts{
		Name: "skeleton_http_requests_total",
		Help: "Total number of HTTP requests.",
	}, []string{"method", "route", "status"})
	httpDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
		Name:    "skeleton_http_request_duration_seconds",
		Help:    "HTTP request latency in seconds.",
		Buckets: prometheus.DefBuckets,
	}, []string{"method", "route", "status"})
)

func init() {
	prometheus.MustRegister(httpRequests, httpDuration)
}

func Metrics() gin.HandlerFunc {
	return func(c *gin.Context) {
		started := time.Now()
		c.Next()
		route := c.FullPath()
		if route == "" {
			route = "unmatched"
		}
		status := strconv.Itoa(c.Writer.Status())
		httpRequests.WithLabelValues(c.Request.Method, route, status).Inc()
		httpDuration.WithLabelValues(c.Request.Method, route, status).Observe(time.Since(started).Seconds())
	}
}