1 files changed, 114 insertions, 0 deletions
diff --git a/plugins/base/smtp.go b/plugins/base/smtp.go
new file mode 100644
index 0000000..9ade78f
--- /dev/null
+++ b/plugins/base/smtp.go
@@ -0,0 +1,114 @@
+package koushinbase
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strings"
+	"time"
+
+	"github.com/emersion/go-message/mail"
+	"github.com/emersion/go-smtp"
+)
+
+func quote(r io.Reader) (string, error) {
+	scanner := bufio.NewScanner(r)
+	var builder strings.Builder
+	for scanner.Scan() {
+		builder.WriteString("> ")
+		builder.Write(scanner.Bytes())
+		builder.WriteString("\n")
+	}
+	if err := scanner.Err(); err != nil {
+		return "", fmt.Errorf("quote: failed to read original message: %s", err)
+	}
+	return builder.String(), nil
+}
+
+type OutgoingMessage struct {
+	From      string
+	To        []string
+	Subject   string
+	InReplyTo string
+	Text      string
+}
+
+func (msg *OutgoingMessage) ToString() string {
+	return strings.Join(msg.To, ", ")
+}
+
+func (msg *OutgoingMessage) WriteTo(w io.Writer) error {
+	from := []*mail.Address{{"", msg.From}}
+
+	to := make([]*mail.Address, len(msg.To))
+	for i, addr := range msg.To {
+		to[i] = &mail.Address{"", addr}
+	}
+
+	var h mail.Header
+	h.SetDate(time.Now())
+	h.SetAddressList("From", from)
+	h.SetAddressList("To", to)
+	if msg.Subject != "" {
+		h.SetText("Subject", msg.Subject)
+	}
+	if msg.InReplyTo != "" {
+		h.Set("In-Reply-To", msg.InReplyTo)
+	}
+
+	mw, err := mail.CreateWriter(w, h)
+	if err != nil {
+		return fmt.Errorf("failed to create mail writer: %v", err)
+	}
+
+	var th mail.InlineHeader
+	th.Set("Content-Type", "text/plain; charset=utf-8")
+
+	tw, err := mw.CreateSingleInline(th)
+	if err != nil {
+		return fmt.Errorf("failed to create text part: %v", err)
+	}
+	defer tw.Close()
+
+	if _, err := io.WriteString(tw, msg.Text); err != nil {
+		return fmt.Errorf("failed to write text part: %v", err)
+	}
+
+	if err := tw.Close(); err != nil {
+		return fmt.Errorf("failed to close text part: %v", err)
+	}
+
+	if err := mw.Close(); err != nil {
+		return fmt.Errorf("failed to close mail writer: %v", err)
+	}
+
+	return nil
+}
+
+func sendMessage(c *smtp.Client, msg *OutgoingMessage) error {
+	if err := c.Mail(msg.From, nil); err != nil {
+		return fmt.Errorf("MAIL FROM failed: %v", err)
+	}
+
+	for _, to := range msg.To {
+		if err := c.Rcpt(to); err != nil {
+			return fmt.Errorf("RCPT TO failed: %v", err)
+		}
+	}
+
+	w, err := c.Data()
+	if err != nil {
+		return fmt.Errorf("DATA failed: %v", err)
+	}
+	defer w.Close()
+
+	if err := msg.WriteTo(w); err != nil {
+		return fmt.Errorf("failed to write outgoing message: %v", err)
+	}
+
+	if err := w.Close(); err != nil {
+		return fmt.Errorf("failed to close SMTP data writer: %v", err)
+	}
+
+	return nil
+}