initial rebuild

internal/smtp/mailer.go

@@ -0,0 +1,116 @@
+package smtp
+
+import (
+	"bytes"
+	"time"
+
+	"github.com/glueops/autoglue/internal/assets"
+	"github.com/glueops/autoglue/internal/funcs"
+	"github.com/wneessen/go-mail"
+
+	htmlTemplate "html/template"
+	textTemplate "text/template"
+)
+
+const defaultTimeout = 10 * time.Second
+
+type Mailer struct {
+	client *mail.Client
+	from   string
+}
+
+func NewMailer(host string, port int, username, password, from string) (*Mailer, error) {
+	opts := []mail.Option{
+		mail.WithTimeout(defaultTimeout),
+		mail.WithPort(port),
+		// IMPORTANT for Mailpit/local dev: no TLS
+		mail.WithTLSPolicy(mail.NoTLS),
+	}
+
+	if username != "" {
+		opts = append(opts,
+			mail.WithSMTPAuth(mail.SMTPAuthLogin),
+			mail.WithUsername(username),
+			mail.WithPassword(password),
+		)
+	}
+
+	client, err := mail.NewClient(host, opts...)
+	if err != nil {
+		return nil, err
+	}
+
+	mailer := &Mailer{
+		client: client,
+		from:   from,
+	}
+
+	return mailer, nil
+}
+
+func (m *Mailer) Send(recipient string, data any, patterns ...string) error {
+	for i := range patterns {
+		patterns[i] = "emails/" + patterns[i]
+	}
+	msg := mail.NewMsg()
+
+	err := msg.To(recipient)
+	if err != nil {
+		return err
+	}
+
+	err = msg.From(m.from)
+	if err != nil {
+		return err
+	}
+
+	ts, err := textTemplate.New("").Funcs(funcs.TemplateFuncs).ParseFS(assets.EmbeddedFiles, patterns...)
+	if err != nil {
+		return err
+	}
+
+	subject := new(bytes.Buffer)
+	err = ts.ExecuteTemplate(subject, "subject", data)
+	if err != nil {
+		return err
+	}
+
+	msg.Subject(subject.String())
+
+	plainBody := new(bytes.Buffer)
+	err = ts.ExecuteTemplate(plainBody, "plainBody", data)
+	if err != nil {
+		return err
+	}
+
+	msg.SetBodyString(mail.TypeTextPlain, plainBody.String())
+
+	if ts.Lookup("htmlBody") != nil {
+		ts, err := htmlTemplate.New("").Funcs(funcs.TemplateFuncs).ParseFS(assets.EmbeddedFiles, patterns...)
+		if err != nil {
+			return err
+		}
+
+		htmlBody := new(bytes.Buffer)
+		err = ts.ExecuteTemplate(htmlBody, "htmlBody", data)
+		if err != nil {
+			return err
+		}
+
+		msg.AddAlternativeString(mail.TypeTextHTML, htmlBody.String())
+	}
+
+	for i := 1; i <= 3; i++ {
+		err = m.client.DialAndSend(msg)
+
+		if nil == err {
+			return nil
+		}
+
+		if i != 3 {
+			time.Sleep(2 * time.Second)
+		}
+	}
+
+	return err
+}