Change resend to using smtp

Signed-off-by: Asai Neko <sugar@sne.moe>

pkgs/email/email.go

@@ -0,0 +1,70 @@
+package email
+
+import (
+	"crypto/tls"
+	"errors"
+	"strings"
+	"time"
+
+	"github.com/spf13/viper"
+	gomail "gopkg.in/gomail.v2"
+)
+
+type Client struct {
+	dialer *gomail.Dialer
+	from   string
+}
+
+func NewSMTPClient() (*Client, error) {
+	host := viper.GetString("email.host")
+	port := viper.GetInt("email.port")
+	user := viper.GetString("email.username")
+	pass := viper.GetString("email.password")
+	from := viper.GetString("email.from")
+
+	security := strings.ToLower(viper.GetString("email.security"))
+	insecure := viper.GetBool("email.insecure_skip_verify")
+
+	if host == "" || port == 0 || user == "" || pass == "" {
+		return nil, errors.New("SMTP config not set")
+	}
+
+	dialer := gomail.NewDialer(host, port, user, pass)
+
+	dialer.TLSConfig = &tls.Config{
+		ServerName:         host,
+		InsecureSkipVerify: insecure,
+	}
+
+	switch security {
+	case "ssl":
+		dialer.SSL = true
+	case "starttls":
+		dialer.SSL = false
+	case "plain", "":
+		dialer.SSL = false
+		dialer.TLSConfig = nil
+	default:
+		return nil, errors.New("unknown smtp security mode: " + security)
+	}
+
+	return &Client{
+		dialer: dialer,
+		from:   from,
+	}, nil
+}
+
+func (c *Client) Send(to, subject, html string) (string, error) {
+	m := gomail.NewMessage()
+
+	m.SetHeader("From", c.from)
+	m.SetHeader("To", to)
+	m.SetHeader("Subject", subject)
+	m.SetBody("text/html", html)
+
+	if err := c.dialer.DialAndSend(m); err != nil {
+		return "", err
+	}
+
+	return time.Now().Format(time.RFC3339Nano), nil
+}