replaced fmt.Println with logger usage

internal/server/middleware/auth.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"time"
 
@@ -18,6 +19,7 @@ import (
 
 type (
 	Auth struct {
+		log         *slog.Logger
 		auth        *authentication.Authenticator
 		newLoginURL LoginURLProviderFunc
 		accts       *accounts.Store
@@ -36,11 +38,13 @@ type (
 )
 
 func NewAuth(
+	logger *slog.Logger,
 	auth *authentication.Authenticator,
 	newLoginURL LoginURLProviderFunc,
 	accts *accounts.Store,
 ) *Auth {
 	return &Auth{
+		log:         logger,
 		auth:        auth,
 		newLoginURL: newLoginURL,
 		accts:       accts,
@@ -133,7 +137,7 @@ func (a *Auth) AuthenticateAndAddIdentity(f response.HandlerFunc, assertions ...
 		if refreshFloor := expiration.Add(-(idTokenLifetime / 4)); refreshFloor.Before(now) {
 			accessToken, expiration, err = a.auth.RefreshAccessToken(ctx, accessToken)
 			if err != nil {
-				fmt.Println("failed to refresh access token:", err)
+				a.log.Warn("failed to refresh access token", "error", err)
 				return response.TemporaryRedirect("/").
 					Body(io.NopCloser(bytes.NewBuffer([]byte(fmt.Sprintf("failed to refresh access token: %v", err))))).
 					Cookie(cookies.Expired("access_token")), nil