diff --git a/bot/bot.go b/bot/bot.go
index 46cf4ac..83826be 100644
--- a/bot/bot.go
+++ b/bot/bot.go
@@ -2,9 +2,7 @@ package bot
 
 import (
 	"context"
-	"errors"
 	"fmt"
-	"strings"
 	"sync"
 
 	"github.com/getsentry/sentry-go"
@@ -13,8 +11,6 @@ import (
 	"maunium.net/go/mautrix/event"
 	"maunium.net/go/mautrix/format"
 	"maunium.net/go/mautrix/id"
-
-	"gitlab.com/etke.cc/postmoogle/utils"
 )
 
 // Bot represents matrix bot
@@ -80,99 +76,6 @@ func (b *Bot) Start(statusMsg string) error {
 	return b.lp.Start(statusMsg)
 }
 
-func (b *Bot) email2content(email *utils.Email, cfg settings) *event.MessageEventContent {
-	var text strings.Builder
-	if !cfg.NoSender() {
-		text.WriteString("From: ")
-		text.WriteString(email.From)
-		text.WriteString("\n\n")
-	}
-	if !cfg.NoSubject() {
-		text.WriteString("# ")
-		text.WriteString(email.Subject)
-		text.WriteString("\n\n")
-	}
-	if email.HTML != "" && !cfg.NoHTML() {
-		text.WriteString(format.HTMLToMarkdown(email.HTML))
-	} else {
-		text.WriteString(email.Text)
-	}
-
-	content := format.RenderMarkdown(text.String(), true, true)
-	return &content
-}
-
-// Send email to matrix room
-func (b *Bot) Send(ctx context.Context, email *utils.Email) error {
-	roomID, ok := b.GetMapping(utils.Mailbox(email.To))
-	if !ok {
-		return errors.New("room not found")
-	}
-
-	cfg, err := b.getSettings(roomID)
-	if err != nil {
-		b.Error(ctx, roomID, "cannot get settings: %v", err)
-	}
-
-	contentParsed := b.email2content(email, cfg)
-	content := &event.Content{
-		Raw: map[string]interface{}{
-			eventMessageIDkey: email.MessageID,
-			eventInReplyToKey: email.InReplyTo,
-		},
-		Parsed: contentParsed,
-	}
-
-	var threadID id.EventID
-	if email.InReplyTo != "" && !cfg.NoThreads() {
-		threadID = b.getThreadID(roomID, email.InReplyTo)
-		if threadID != "" {
-			contentParsed.SetRelatesTo(&event.RelatesTo{
-				Type:    event.RelThread,
-				EventID: threadID,
-			})
-			b.setThreadID(roomID, email.MessageID, threadID)
-		}
-	}
-	eventID, serr := b.lp.Send(roomID, content)
-	if serr != nil {
-		return serr
-	}
-
-	if threadID == "" {
-		b.setThreadID(roomID, email.MessageID, eventID)
-		threadID = eventID
-	}
-
-	if !cfg.NoFiles() {
-		b.sendFiles(ctx, roomID, email.Files, threadID)
-	}
-	return nil
-}
-
-func (b *Bot) sendFiles(ctx context.Context, roomID id.RoomID, files []*utils.File, threadID id.EventID) {
-	for _, file := range files {
-		req := file.Convert()
-		resp, err := b.lp.GetClient().UploadMedia(req)
-		if err != nil {
-			b.Error(ctx, roomID, "cannot upload file %s: %v", req.FileName, err)
-			continue
-		}
-		_, err = b.lp.Send(roomID, &event.MessageEventContent{
-			MsgType: event.MsgFile,
-			Body:    req.FileName,
-			URL:     resp.ContentURI.CUString(),
-			RelatesTo: &event.RelatesTo{
-				Type:    event.RelThread,
-				EventID: threadID,
-			},
-		})
-		if err != nil {
-			b.Error(ctx, roomID, "cannot send uploaded file %s: %v", req.FileName, err)
-		}
-	}
-}
-
 // GetMappings returns mapping of mailbox = room
 func (b *Bot) GetMapping(mailbox string) (id.RoomID, bool) {
 	v, ok := b.rooms.Load(mailbox)
diff --git a/bot/email.go b/bot/email.go
new file mode 100644
index 0000000..e4849af
--- /dev/null
+++ b/bot/email.go
@@ -0,0 +1,101 @@
+package bot
+
+import (
+	"context"
+	"errors"
+	"strings"
+
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/format"
+	"maunium.net/go/mautrix/id"
+
+	"gitlab.com/etke.cc/postmoogle/utils"
+)
+
+func email2content(email *utils.Email, cfg settings, threadID id.EventID) *event.Content {
+	var text strings.Builder
+	if !cfg.NoSender() {
+		text.WriteString("From: ")
+		text.WriteString(email.From)
+		text.WriteString("\n\n")
+	}
+	if !cfg.NoSubject() {
+		text.WriteString("# ")
+		text.WriteString(email.Subject)
+		text.WriteString("\n\n")
+	}
+	if email.HTML != "" && !cfg.NoHTML() {
+		text.WriteString(format.HTMLToMarkdown(email.HTML))
+	} else {
+		text.WriteString(email.Text)
+	}
+
+	parsed := format.RenderMarkdown(text.String(), true, true)
+	parsed.RelatesTo = utils.RelatesTo(cfg.NoThreads(), threadID)
+
+	content := event.Content{
+		Raw: map[string]interface{}{
+			eventMessageIDkey: email.MessageID,
+			eventInReplyToKey: email.InReplyTo,
+		},
+		Parsed: parsed,
+	}
+	return &content
+}
+
+// Send email to matrix room
+func (b *Bot) Send(ctx context.Context, email *utils.Email) error {
+	roomID, ok := b.GetMapping(utils.Mailbox(email.To))
+	if !ok {
+		return errors.New("room not found")
+	}
+
+	cfg, err := b.getSettings(roomID)
+	if err != nil {
+		b.Error(ctx, roomID, "cannot get settings: %v", err)
+	}
+
+	var threadID id.EventID
+	if email.InReplyTo != "" && !cfg.NoThreads() {
+		threadID = b.getThreadID(roomID, email.InReplyTo)
+		if threadID != "" {
+			b.setThreadID(roomID, email.MessageID, threadID)
+		}
+	}
+
+	content := email2content(email, cfg, threadID)
+	eventID, serr := b.lp.Send(roomID, content)
+	if serr != nil {
+		return serr
+	}
+
+	if threadID == "" && !cfg.NoThreads() {
+		b.setThreadID(roomID, email.MessageID, eventID)
+		threadID = eventID
+	}
+
+	if !cfg.NoFiles() {
+		b.sendFiles(ctx, roomID, email.Files, cfg.NoThreads(), threadID)
+	}
+	return nil
+}
+
+func (b *Bot) sendFiles(ctx context.Context, roomID id.RoomID, files []*utils.File, noThreads bool, parentID id.EventID) {
+	for _, file := range files {
+		req := file.Convert()
+		resp, err := b.lp.GetClient().UploadMedia(req)
+		if err != nil {
+			b.Error(ctx, roomID, "cannot upload file %s: %v", req.FileName, err)
+			continue
+		}
+		_, err = b.lp.Send(roomID, &event.MessageEventContent{
+			MsgType:   event.MsgFile,
+			Body:      req.FileName,
+			URL:       resp.ContentURI.CUString(),
+			RelatesTo: utils.RelatesTo(noThreads, parentID),
+		})
+		if err != nil {
+			b.Error(ctx, roomID, "cannot send uploaded file %s: %v", req.FileName, err)
+		}
+	}
+}
diff --git a/utils/matrix.go b/utils/matrix.go
new file mode 100644
index 0000000..faa2a54
--- /dev/null
+++ b/utils/matrix.go
@@ -0,0 +1,26 @@
+package utils
+
+import (
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
+)
+
+// RelatesTo block of matrix event content
+func RelatesTo(noThreads bool, parentID id.EventID) *event.RelatesTo {
+	if parentID == "" {
+		return nil
+	}
+
+	if noThreads {
+		return &event.RelatesTo{
+			InReplyTo: &event.InReplyTo{
+				EventID: parentID,
+			},
+		}
+	}
+
+	return &event.RelatesTo{
+		Type:    event.RelThread,
+		EventID: parentID,
+	}
+}