package middleware

import (
	"net/http"
	"strconv"
	"time"

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

var (
	httpRequestsTotal = promauto.NewCounterVec(
		prometheus.CounterOpts{
			Name: "http_requests_total",
			Help: "Total number of HTTP requests",
		},
		[]string{"method", "path", "status"},
	)

	httpRequestDuration = promauto.NewHistogramVec(
		prometheus.HistogramOpts{
			Name:    "http_request_duration_seconds",
			Help:    "Duration of HTTP requests",
			Buckets: []float64{0.1, 0.5, 1, 2.5, 5, 10},
		},
		[]string{"method", "path"},
	)

	httpResponseSize = promauto.NewSummaryVec(
		prometheus.SummaryOpts{
			Name: "http_response_size_bytes",
			Help: "Size of HTTP responses",
		},
		[]string{"method", "path"},
	)
)

// MetricsMiddleware собирает метрики для Prometheus
func MetricsMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		rw := &responseWriter{w, http.StatusOK, 0}

		next.ServeHTTP(rw, r)

		duration := time.Since(start).Seconds()
		status := strconv.Itoa(rw.status)

		// Регистрируем метрики
		httpRequestsTotal.WithLabelValues(
			r.Method,
			r.URL.Path,
			status,
		).Inc()

		httpRequestDuration.WithLabelValues(
			r.Method,
			r.URL.Path,
		).Observe(duration)

		httpResponseSize.WithLabelValues(
			r.Method,
			r.URL.Path,
		).Observe(float64(rw.size))
	})
}