package middleware

import (
	"net/http"

	"github.com/google/uuid"
)

const RequestIDHeader = "X-Request-ID"

// RequestID adds a unique X-Request-ID to each request and to the request context.
// The same ID is set on the response header for tracing.
func RequestID(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		id := r.Header.Get(RequestIDHeader)
		if id == "" {
			id = uuid.New().String()
		}
		w.Header().Set(RequestIDHeader, id)
		next.ServeHTTP(w, r)
	})
}