package mw

import (
	"net/http"

	"code.nochebuena.dev/einherjar/core/logz"
)

// RequestID injects a unique request ID into the context (via [logz.WithRequestID])
// and sets the X-Request-ID response header.
// generator is called once per request — pass uuid.NewString or a custom function.
func RequestID(generator func() string) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			id := generator()
			ctx := logz.WithRequestID(r.Context(), id)
			r = r.WithContext(ctx)
			w.Header().Set("X-Request-ID", id)
			next.ServeHTTP(w, r)
		})
	}
}