package services import ( "crypto/tls" "fmt" "log" "net/smtp" "strconv" ) type EmailService struct { smtpHost string smtpPort string smtpUsername string smtpPassword string fromEmail string fromName string } func NewEmailService(smtpHost, smtpPort, smtpUsername, smtpPassword, fromEmail, fromName string) *EmailService { return &EmailService{ smtpHost: smtpHost, smtpPort: smtpPort, smtpUsername: smtpUsername, smtpPassword: smtpPassword, fromEmail: fromEmail, fromName: fromName, } } func (s *EmailService) SendOTP(email, otp string) error { log.Printf("SendOTP: Attempting to send OTP to %s via %s:%s", email, s.smtpHost, s.smtpPort) // Validate SMTP configuration if s.smtpHost == "" || s.smtpPort == "" { log.Printf("SendOTP: SMTP configuration missing - Host: %s, Port: %s", s.smtpHost, s.smtpPort) return fmt.Errorf("SMTP configuration is missing") } if s.smtpUsername == "" || s.smtpPassword == "" { log.Printf("SendOTP: SMTP credentials missing") return fmt.Errorf("SMTP credentials are missing") } // Convert port to int port, err := strconv.Atoi(s.smtpPort) if err != nil { log.Printf("SendOTP: Invalid SMTP port %s: %v", s.smtpPort, err) return fmt.Errorf("invalid SMTP port: %w", err) } // Setup authentication auth := smtp.PlainAuth("", s.smtpUsername, s.smtpPassword, s.smtpHost) log.Printf("SendOTP: SMTP authentication configured for %s", s.smtpHost) // Email content subject := "Password Reset Verification Code" htmlBody := fmt.Sprintf(` Password Reset Verification

Password Reset Request

Hello,

You have requested to reset your password. Please use the verification code below to complete the process:

%s

⚠️ Important: This verification code will expire in 10 minutes. For security reasons, please do not share this code with anyone.

If you did not request this password reset, please ignore this email or contact our support team if you have concerns.

Best regards,
%s Team

This is an automated message. Please do not reply to this email.

This email was sent to %s
If you have any questions, please contact our support team.

`, otp, s.fromName, "2026", s.fromName, email) // Build email message msg := []byte(fmt.Sprintf("From: %s <%s>\r\nTo: %s\r\nSubject: %s\r\nMIME-Version: 1.0\r\nContent-Type: text/html; charset=UTF-8\r\n\r\n%s", s.fromName, s.fromEmail, email, subject, htmlBody)) // Send email based on port to := []string{email} addr := fmt.Sprintf("%s:%d", s.smtpHost, port) log.Printf("SendOTP: Sending email to %s via %s (port %d)", email, addr, port) // Port 465 requires SSL/TLS from the start if port == 465 { err = s.sendWithSSL(addr, auth, s.fromEmail, to, msg) } else { // Port 587 uses STARTTLS err = smtp.SendMail(addr, auth, s.fromEmail, to, msg) } if err != nil { log.Printf("SendOTP: Failed to send email to %s: %v", email, err) return fmt.Errorf("failed to send email: %w", err) } log.Printf("SendOTP: Email sent successfully to %s", email) return nil } // sendWithSSL sends email using SSL/TLS connection (for port 465) func (s *EmailService) sendWithSSL(addr string, auth smtp.Auth, from string, to []string, msg []byte) error { // Connect to SMTP server conn, err := tls.Dial("tcp", addr, &tls.Config{ ServerName: s.smtpHost, InsecureSkipVerify: false, // Set to true only for testing with self-signed certs }) if err != nil { return fmt.Errorf("failed to connect to SMTP server: %w", err) } defer conn.Close() // Create SMTP client client, err := smtp.NewClient(conn, s.smtpHost) if err != nil { return fmt.Errorf("failed to create SMTP client: %w", err) } defer client.Close() // Authenticate if err = client.Auth(auth); err != nil { return fmt.Errorf("failed to authenticate: %w", err) } // Set sender if err = client.Mail(from); err != nil { return fmt.Errorf("failed to set sender: %w", err) } // Set recipients for _, recipient := range to { if err = client.Rcpt(recipient); err != nil { return fmt.Errorf("failed to set recipient %s: %w", recipient, err) } } // Send email body writer, err := client.Data() if err != nil { return fmt.Errorf("failed to get data writer: %w", err) } if _, err = writer.Write(msg); err != nil { return fmt.Errorf("failed to write message: %w", err) } if err = writer.Close(); err != nil { return fmt.Errorf("failed to close writer: %w", err) } // Quit if err = client.Quit(); err != nil { return fmt.Errorf("failed to quit: %w", err) } return nil }