fix: update MaxFrequency error message to reflect number of seconds (s…

…upabase#1540)

## What kind of change does this PR introduce?

Currently we use a constant value on number of seconds left before a
developer can send a follow up email confirmation. This can prove
confusing if developer has a custom setting for `MaxFrequency` on `Sms`
or `SMTP`

We change some core email related routes to show the exact number of
seconds. This includes `signup`, `magic_link` and `email_change`

The rest will follow should this change roll out smoothly. Tested the
three flows locally by triggering the max frequency limit and checking
that the number of seconds show up as expected.

internal/api/errors.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"os"
 	"runtime/debug"
+	"time"
 
 	"github.com/pkg/errors"
 	"github.com/supabase/auth/internal/observability"
@@ -312,3 +313,9 @@ func HandleResponseError(err error, w http.ResponseWriter, r *http.Request) {
 		}
 	}
 }
+
+func generateFrequencyLimitErrorMessage(timeStamp *time.Time, maxFrequency time.Duration) string {
+	now := time.Now()
+	left := timeStamp.Add(maxFrequency).Sub(now) / time.Second
+	return fmt.Sprintf("For security purposes, you can only request this after %d seconds.", left)
+}

internal/api/magic_link.go

@@ -142,7 +142,7 @@ func (a *API) MagicLink(w http.ResponseWriter, r *http.Request) error {
 	})
 	if err != nil {
 		if errors.Is(err, MaxFrequencyLimitError) {
-			return tooManyRequestsError(ErrorCodeOverEmailSendRateLimit, "For security purposes, you can only request this once every 60 seconds")
+			return tooManyRequestsError(ErrorCodeOverEmailSendRateLimit, generateFrequencyLimitErrorMessage(user.RecoverySentAt, config.SMTP.MaxFrequency))
 		}
 		return internalServerError("Error sending magic link").WithInternalError(err)
 	}

internal/api/signup.go

@@ -2,7 +2,6 @@ package api
 
 import (
 	"context"
-	"fmt"
 	"net/http"
 	"time"
 
@@ -246,9 +245,7 @@ func (a *API) Signup(w http.ResponseWriter, r *http.Request) error {
 				}
 				if terr = a.sendConfirmation(r, tx, user, flowType); terr != nil {
 					if errors.Is(terr, MaxFrequencyLimitError) {
-						now := time.Now()
-						left := user.ConfirmationSentAt.Add(config.SMTP.MaxFrequency).Sub(now) / time.Second
-						return tooManyRequestsError(ErrorCodeOverEmailSendRateLimit, fmt.Sprintf("For security purposes, you can only request this after %d seconds.", left))
+						return tooManyRequestsError(ErrorCodeOverEmailSendRateLimit, generateFrequencyLimitErrorMessage(user.ConfirmationSentAt, config.SMTP.MaxFrequency))
 					}
 					return internalServerError("Error sending confirmation mail").WithInternalError(terr)
 				}

internal/api/user.go

@@ -214,7 +214,7 @@ func (a *API) UserUpdate(w http.ResponseWriter, r *http.Request) error {
 			}
 			if terr = a.sendEmailChange(r, tx, user, params.Email, flowType); terr != nil {
 				if errors.Is(terr, MaxFrequencyLimitError) {
-					return tooManyRequestsError(ErrorCodeOverEmailSendRateLimit, "For security purposes, you can only request this once every 60 seconds")
+					return tooManyRequestsError(ErrorCodeOverEmailSendRateLimit, generateFrequencyLimitErrorMessage(user.EmailChangeSentAt, config.SMTP.MaxFrequency))
 				}
 				return internalServerError("Error sending change email").WithInternalError(terr)
 			}