Initial QSfera import

Server/services/notifications/pkg/channels/channels.go

@@ -0,0 +1,160 @@
+// Package channels provides different communication channels to notify users.
+package channels
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/tls"
+	"fmt"
+	stdmail "net/mail"
+	"strings"
+	"time"
+
+	"github.com/pkg/errors"
+	mail "github.com/xhit/go-simple-mail/v2"
+
+	"github.com/qsfera/server/pkg/log"
+	"github.com/qsfera/server/services/notifications/pkg/config"
+)
+
+// Channel defines the methods of a communication channel.
+type Channel interface {
+	// SendMessage sends a message to users.
+	SendMessage(ctx context.Context, message *Message) error
+}
+
+// Message represent the already rendered message including the user id opaqueID
+type Message struct {
+	Sender       string
+	Recipient    []string
+	Subject      string
+	TextBody     string
+	HTMLBody     string
+	AttachInline map[string][]byte
+}
+
+// NewMailChannel instantiates a new mail communication channel.
+func NewMailChannel(cfg config.Config, logger log.Logger) (Channel, error) {
+	a, err := stdmail.ParseAddress(cfg.Notifications.SMTP.Sender)
+	if err != nil {
+		logger.Err(err).Msg("parsing error, the 'smtp_sender' must be a valid single RFC 5322 address.")
+		return nil, err
+	}
+	return Mail{
+		conf:        cfg,
+		smtpAddress: *a,
+		logger:      logger,
+	}, nil
+}
+
+// Mail is the communication channel for email.
+type Mail struct {
+	conf        config.Config
+	smtpAddress stdmail.Address
+	logger      log.Logger
+}
+
+func (m Mail) getMailClient() (*mail.SMTPClient, error) {
+	server := mail.NewSMTPClient()
+	server.Host = m.conf.Notifications.SMTP.Host
+	server.Port = m.conf.Notifications.SMTP.Port
+	server.Username = m.conf.Notifications.SMTP.Username
+	if server.Username == "" {
+		// compatibility fallback
+		server.Username = m.conf.Notifications.SMTP.Sender
+	}
+	server.Password = m.conf.Notifications.SMTP.Password
+	if server.TLSConfig == nil {
+		server.TLSConfig = &tls.Config{
+			MinVersion: tls.VersionTLS12,
+		}
+	}
+	server.TLSConfig.InsecureSkipVerify = m.conf.Notifications.SMTP.Insecure
+
+	switch strings.ToLower(m.conf.Notifications.SMTP.Authentication) {
+	case "login":
+		server.Authentication = mail.AuthLogin
+	case "plain":
+		server.Authentication = mail.AuthPlain
+	case "crammd5":
+		server.Authentication = mail.AuthCRAMMD5
+	case "none":
+		server.Authentication = mail.AuthNone
+	case "auto", "":
+		server.Authentication = mail.AuthAuto
+	default:
+		return nil, errors.New("unknown mail authentication method")
+	}
+
+	switch strings.ToLower(m.conf.Notifications.SMTP.Encryption) {
+	case "starttls":
+		server.Encryption = mail.EncryptionSTARTTLS
+		server.TLSConfig.ServerName = m.conf.Notifications.SMTP.Host
+	case "ssltls":
+		server.Encryption = mail.EncryptionSSLTLS
+	case "none":
+		server.Encryption = mail.EncryptionNone
+	default:
+		return nil, errors.New("unknown mail encryption method")
+	}
+
+	smtpClient, err := server.Connect()
+	if err != nil {
+		return nil, err
+	}
+
+	return smtpClient, nil
+}
+
+// SendMessage sends a message to all given users.
+func (m Mail) SendMessage(_ context.Context, message *Message) error {
+	if m.conf.Notifications.SMTP.Host == "" {
+		m.logger.Info().Str("mail", "SendMessage").Msg("failed to send a message. SMTP host is  not set")
+		return nil
+	}
+
+	smtpClient, err := m.getMailClient()
+	if err != nil {
+		return err
+	}
+
+	email := mail.NewMSG()
+	email.SetFrom(appendSender(message.Sender, m.smtpAddress)).AddTo(message.Recipient...)
+	email.SetSubject(message.Subject)
+	email.AddHeader("Message-ID", generateMessageID(m.smtpAddress.Address))
+	email.SetBody(mail.TextPlain, message.TextBody)
+	if message.HTMLBody != "" {
+		email.AddAlternative(mail.TextHTML, message.HTMLBody)
+		for filename, data := range message.AttachInline {
+			email.Attach(&mail.File{Data: data, Name: filename, Inline: true})
+		}
+	}
+
+	return email.Send(smtpClient)
+}
+
+func appendSender(sender string, a stdmail.Address) string {
+	if strings.TrimSpace(sender) != "" {
+		a.Name = strings.TrimSpace(sender + " via " + a.Name)
+	}
+	return a.String()
+}
+
+// generateMessageID generates a unique Message-ID header value according to RFC 5322
+func generateMessageID(domain string) string {
+	// Extract domain from email address if it contains @
+	if idx := strings.LastIndex(domain, "@"); idx != -1 {
+		domain = domain[idx+1:]
+	}
+
+	// Generate random bytes for uniqueness
+	b := make([]byte, 16)
+	if _, err := rand.Read(b); err != nil {
+		// Fallback to timestamp-based ID if random fails
+		return fmt.Sprintf("<%d@%s>", time.Now().UnixNano(), domain)
+	}
+
+	// Create Message-ID: <timestamp.random@domain>
+	timestamp := time.Now().Unix()
+	return fmt.Sprintf("<%d.%x@%s>", timestamp, b, domain)
+}