ilk

svc/internal/mailer/mailer.go

@@ -0,0 +1,148 @@
+package mailer
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net"
+	"net/smtp"
+	"strings"
+	"time"
+)
+
+var ErrInvalidConfig = errors.New("invalid smtp config")
+
+type Mailer struct {
+	cfg Config
+}
+
+type Message struct {
+	To       []string
+	Subject  string
+	Body     string
+	BodyHTML string
+}
+
+func New(cfg Config) *Mailer {
+	return &Mailer{cfg: cfg}
+}
+
+func (m *Mailer) Send(ctx context.Context, msg Message) error {
+	if len(msg.To) == 0 {
+		return errors.New("recipient missing")
+	}
+	if strings.TrimSpace(msg.Subject) == "" {
+		return errors.New("subject missing")
+	}
+
+	// timeout kontrolü (ctx)
+	deadline, ok := ctx.Deadline()
+	if !ok {
+		// default timeout
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, 20*time.Second)
+		defer cancel()
+		deadline, _ = ctx.Deadline()
+	}
+	timeout := time.Until(deadline)
+	if timeout <= 0 {
+		return context.DeadlineExceeded
+	}
+
+	addr := fmt.Sprintf("%s:%d", m.cfg.Host, m.cfg.Port)
+
+	dialer := net.Dialer{Timeout: timeout}
+	conn, err := dialer.DialContext(ctx, "tcp", addr)
+	if err != nil {
+		return fmt.Errorf("smtp dial: %w", err)
+	}
+	defer conn.Close()
+
+	c, err := smtp.NewClient(conn, m.cfg.Host)
+	if err != nil {
+		return fmt.Errorf("smtp client: %w", err)
+	}
+	defer c.Close()
+
+	// STARTTLS
+	if m.cfg.StartTLS {
+		tlsCfg := &tls.Config{
+			ServerName: m.cfg.Host,
+			MinVersion: tls.VersionTLS12,
+		}
+		if err := c.StartTLS(tlsCfg); err != nil {
+			return fmt.Errorf("starttls: %w", err)
+		}
+	}
+
+	// AUTH
+	auth := smtp.PlainAuth("", m.cfg.Username, m.cfg.Password, m.cfg.Host)
+	if err := c.Auth(auth); err != nil {
+		return fmt.Errorf("smtp auth: %w", err)
+	}
+
+	// MAIL FROM
+	if err := c.Mail(m.cfg.From); err != nil {
+		return fmt.Errorf("mail from: %w", err)
+	}
+
+	// RCPT TO
+	for _, rcpt := range msg.To {
+		rcpt = strings.TrimSpace(rcpt)
+		if rcpt == "" {
+			continue
+		}
+		if err := c.Rcpt(rcpt); err != nil {
+			return fmt.Errorf("rcpt %s: %w", rcpt, err)
+		}
+	}
+
+	w, err := c.Data()
+	if err != nil {
+		return fmt.Errorf("data: %w", err)
+	}
+
+	// basit mime
+	contentType := "text/plain; charset=UTF-8"
+	body := msg.Body
+	if strings.TrimSpace(msg.BodyHTML) != "" {
+		contentType = "text/html; charset=UTF-8"
+		body = msg.BodyHTML
+	}
+
+	raw := buildMIME(m.cfg.From, msg.To, msg.Subject, contentType, body)
+
+	_, writeErr := w.Write([]byte(raw))
+	closeErr := w.Close()
+
+	if writeErr != nil {
+		return fmt.Errorf("write body: %w", writeErr)
+	}
+	if closeErr != nil {
+		return fmt.Errorf("close body: %w", closeErr)
+	}
+
+	if err := c.Quit(); err != nil {
+		return fmt.Errorf("quit: %w", err)
+	}
+
+	return nil
+}
+
+func buildMIME(from string, to []string, subject, contentType, body string) string {
+	// Subject UTF-8 basit hali (gerekirse sonra MIME encoded-word ekleriz)
+	headers := []string{
+		"From: " + from,
+		"To: " + strings.Join(to, ", "),
+		"Subject: " + subject,
+		"MIME-Version: 1.0",
+		"Content-Type: " + contentType,
+		"",
+	}
+	return strings.Join(headers, "\r\n") + "\r\n" + body + "\r\n"
+}
+
+type MailerInterface interface {
+	Send(ctx context.Context, msg Message) error
+}