Add plaintext toggle (#476)

Co-authored-by: Niko Köser <koeserniko@gmail.com>

service/mail/mail.go

@@ -11,6 +11,7 @@ import (
 
 // Mail struct holds necessary data to send emails.
 type Mail struct {
+	usePlainText      bool
 	senderAddress     string
 	smtpHostAddr      string
 	smtpAuth          smtp.Auth
@@ -20,12 +21,23 @@ type Mail struct {
 // New returns a new instance of a Mail notification service.
 func New(senderAddress, smtpHostAddress string) *Mail {
 	return &Mail{
+		usePlainText:      false,
 		senderAddress:     senderAddress,
 		smtpHostAddr:      smtpHostAddress,
 		receiverAddresses: []string{},
 	}
 }
 
+// BodyType is used to specify the format of the body.
+type BodyType int
+
+const (
+	// PlainText is used to specify that the body is plain text.
+	PlainText BodyType = iota
+	// HTML is used to specify that the body is HTML.
+	HTML
+)
+
 // AuthenticateSMTP authenticates you to send emails via smtp.
 // Example values: "", "test@gmail.com", "password123", "smtp.gmail.com"
 // For more information about smtp authentication, see here:
@@ -41,18 +53,38 @@ func (m *Mail) AddReceivers(addresses ...string) {
 	m.receiverAddresses = append(m.receiverAddresses, addresses...)
 }
 
-// Send takes a message subject and a message body and sends them to all previously set chats. Message body supports
+// BodyFormat can be used to specify the format of the body.
-// html as markup language.
+// Default BodyType is HTML.
-func (m Mail) Send(ctx context.Context, subject, message string) error {
+func (m *Mail) BodyFormat(format BodyType) {
+	switch format {
+	case PlainText:
+		m.usePlainText = true
+	default:
+		m.usePlainText = false
+	}
+}
+
+func (m *Mail) newEmail(subject, message string) *email.Email {
 	msg := &email.Email{
 		To:      m.receiverAddresses,
 		From:    m.senderAddress,
 		Subject: subject,
-		// Text:    []byte("Text Body is, of course, supported!"),
-		HTML:    []byte(message),
 		Headers: textproto.MIMEHeader{},
 	}
 
+	if m.usePlainText {
+		msg.Text = []byte(message)
+	} else {
+		msg.HTML = []byte(message)
+	}
+	return msg
+}
+
+// Send takes a message subject and a message body and sends them to all previously set chats. Message body supports
+// html as markup language.
+func (m Mail) Send(ctx context.Context, subject, message string) error {
+	msg := m.newEmail(subject, message)
+
 	var err error
 	select {
 	case <-ctx.Done():

service/mail/mail_test.go

@@ -0,0 +1,52 @@
+package mail
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMail_newEmailHtml(t *testing.T) {
+	t.Parallel()
+
+	text := "test"
+	m := New("foo", "server")
+	email := m.newEmail("test", text)
+
+	assert.False(t, m.usePlainText)
+	assert.Equal(t, []byte(nil), email.Text)
+	assert.Equal(t, []byte(text), email.HTML)
+}
+
+func TestMail_newEmailText(t *testing.T) {
+	t.Parallel()
+
+	text := "test"
+	m := New("foo", "server")
+	m.BodyFormat(PlainText)
+	email := m.newEmail("test", text)
+
+	assert.True(t, m.usePlainText)
+	assert.Equal(t, []byte(text), email.Text)
+	assert.Equal(t, []byte(nil), email.HTML)
+}
+
+func TestMail_AddReceivers(t *testing.T) {
+	t.Parallel()
+
+	m := New("foo", "server")
+	m.AddReceivers("test")
+
+	assert.Len(t, m.receiverAddresses, 1)
+	assert.Equal(t, "test", m.receiverAddresses[0])
+}
+
+func TestMail_AuthenticateSMTP(t *testing.T) {
+	t.Parallel()
+
+	m := New("foo", "server")
+	assert.Nil(t, m.smtpAuth)
+
+	m.AuthenticateSMTP("test", "test", "test", "test")
+	assert.NotNil(t, m.smtpAuth)
+}