appview: email: support multiple recipients on `SendEmail`

also remove unnecessary error wrap

Signed-off-by: Seongmin Lee <[e-mail]>

appview/email/email.go

···
 package email
 
 import (
-	"fmt"
 	"net"
 	"regexp"
 	"strings"
···
 
 type Email struct {
 	From    string
-	To      string
 	Subject string
 	Text    string
 	Html    string
 	APIKey  string
 }
 
-func SendEmail(email Email) error {
+func SendEmail(email Email, recipients ...string) error {
 	client := resend.NewClient(email.APIKey)
 	_, err := client.Emails.Send(&resend.SendEmailRequest{
 		From:    email.From,
-		To:      []string{email.To},
+		To:      recipients,
 		Subject: email.Subject,
 		Text:    email.Text,
 		Html:    email.Html,
 	})
-	if err != nil {
-		return fmt.Errorf("error sending email: %w", err)
-	}
-	return nil
+	return err
 }
 
 func IsValidEmail(email string) bool {

appview/settings/settings.go

···
 	return email.Email{
 		APIKey:  s.Config.Resend.ApiKey,
 		From:    s.Config.Resend.SentFrom,
-		To:      emailAddr,
 		Subject: "Verify your Tangled email",
 		Text: `Click the link below (or copy and paste it into your browser) to verify your email address.
 ` + verifyURL,
···
 func (s *Settings) sendVerificationEmail(w http.ResponseWriter, did, emailAddr, code string, errorContext string) error {
 	emailToSend := s.buildVerificationEmail(emailAddr, did, code)
 
-	err := email.SendEmail(emailToSend)
+	err := email.SendEmail(emailToSend, emailAddr)
 	if err != nil {
-		log.Printf("sending email: %s", err)
+		log.Printf("failed to send email: %s", err)
 		s.Pages.Notice(w, "settings-emails-error", fmt.Sprintf("Unable to send verification email at this moment, try again later. %s", errorContext))
 		return err
 	}

appview/signup/signup.go

···
 		em := email.Email{
 			APIKey:  s.config.Resend.ApiKey,
 			From:    s.config.Resend.SentFrom,
-			To:      emailId,
 			Subject: "Verify your Tangled account",
 			Text: `Copy and paste this code below to verify your account on Tangled.
 		` + code,
···
 <p><code>` + code + `</code></p>`,
 		}
 
-		err = email.SendEmail(em)
+		err = email.SendEmail(em, emailId)
 		if err != nil {
 			s.l.Error("failed to send email", "error", err)
 			s.pages.Notice(w, noticeId, "Failed to send email.")