(Feat): Initial Commit

internal/mailer/transport/smtp.go

@@ -0,0 +1,56 @@
+package transport
+
+import (
+	"fmt"
+	"net"
+	"net/smtp"
+	"strconv"
+
+	"github.com/jordan-wright/email"
+)
+
+type SMTPMailTransport struct {
+	config SMTPMailTransportConfig
+	addr   string
+	auth   smtp.Auth
+}
+
+func NewSMTP(config SMTPMailTransportConfig) *SMTPMailTransport {
+	mailTransport := &SMTPMailTransport{
+		config: config,
+		addr:   net.JoinHostPort(config.Host, strconv.Itoa(config.Port)),
+		auth:   nil,
+	}
+
+	switch config.AuthType {
+	case SMTPAuthTypePlain:
+		mailTransport.auth = smtp.PlainAuth("", config.Username, config.Password, config.Host)
+	case SMTPAuthTypeCRAMMD5:
+		mailTransport.auth = smtp.CRAMMD5Auth(config.Username, config.Password)
+	case SMTPAuthTypeLogin:
+		mailTransport.auth = LoginAuth(config.Username, config.Password, config.Host)
+	}
+
+	return mailTransport
+}
+
+func (m *SMTPMailTransport) Send(mail *email.Email) error {
+	var err error
+
+	switch m.config.Encryption {
+	case SMTPEncryptionNone:
+		err = mail.Send(m.addr, m.auth)
+	case SMTPEncryptionTLS:
+		err = mail.SendWithTLS(m.addr, m.auth, m.config.TLSConfig)
+	case SMTPEncryptionStartTLS:
+		err = mail.SendWithStartTLS(m.addr, m.auth, m.config.TLSConfig)
+	default:
+		return fmt.Errorf("invalid SMTP encryption %q", m.config.Encryption)
+	}
+
+	if err != nil {
+		return fmt.Errorf("failed to send email: %w", err)
+	}
+
+	return nil
+}