From 69f20e56706ad7fb93813f4c3f2058bb6f85de30 Mon Sep 17 00:00:00 2001
From: Aine <aine@etke.cc>
Date: Mon, 22 Aug 2022 18:43:12 +0300
Subject: [PATCH] try to receive attachments

---
 README.md       |  3 +--
 bot/bot.go      | 25 +++++++++++++++++++++++--
 smtp/server.go  |  2 +-
 smtp/session.go | 29 ++++++++++++++++++++++++-----
 smtp/smtp.go    |  3 ++-
 utils/file.go   | 35 +++++++++++++++++++++++++++++++++++
 6 files changed, 86 insertions(+), 11 deletions(-)
 create mode 100644 utils/file.go

diff --git a/README.md b/README.md
index cafe5cd..b80f7c0 100644
--- a/README.md
+++ b/README.md
@@ -10,8 +10,7 @@ An Email to Matrix bridge
 - [x] Matrix bot
 - [x] Configuration in room's account data
 - [x] Receive emails to matrix rooms
-- [ ] **BUG**: no auto invites
-- [ ] Receive attachments
+- [x] Receive attachments (untested)
 - [ ] Map email threads to matrix threads
 
 ### Send
diff --git a/bot/bot.go b/bot/bot.go
index d2c8da0..1337071 100644
--- a/bot/bot.go
+++ b/bot/bot.go
@@ -71,7 +71,7 @@ func (b *Bot) Start() error {
 }
 
 // Send email to matrix room
-func (b *Bot) Send(from, to, subject, body string) error {
+func (b *Bot) Send(ctx context.Context, from, to, subject, body string, files []*utils.File) error {
 	roomID, ok := b.rooms[utils.Mailbox(to)]
 	if !ok || roomID == "" {
 		return errors.New("room not found")
@@ -88,7 +88,28 @@ func (b *Bot) Send(from, to, subject, body string) error {
 
 	content := format.RenderMarkdown(text.String(), true, true)
 	_, err := b.lp.Send(roomID, content)
-	return err
+	if err != nil {
+		return err
+	}
+
+	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(),
+		})
+		if err != nil {
+			b.Error(ctx, roomID, "cannot send uploaded file %s: %v", req.FileName, err)
+		}
+	}
+
+	return nil
 }
 
 // GetMappings returns mapping of mailbox = room
diff --git a/smtp/server.go b/smtp/server.go
index 61a1df9..7794baa 100644
--- a/smtp/server.go
+++ b/smtp/server.go
@@ -46,7 +46,7 @@ func Start(domain, port, loglevel string, client Client) error {
 	s.AuthDisabled = true
 	s.ReadTimeout = 10 * time.Second
 	s.WriteTimeout = 10 * time.Second
-	s.MaxMessageBytes = 63 * 1024
+	s.MaxMessageBytes = 128 * 1024
 	if log.GetLevel() == "DEBUG" || log.GetLevel() == "TRACE" {
 		s.Debug = os.Stdout
 	}
diff --git a/smtp/session.go b/smtp/session.go
index 0bdc22f..1927bb1 100644
--- a/smtp/session.go
+++ b/smtp/session.go
@@ -52,17 +52,36 @@ func (s *session) Rcpt(to string) error {
 	return nil
 }
 
+func (s *session) parseAttachments(parts []*enmime.Part) []*utils.File {
+	files := make([]*utils.File, 0, len(parts))
+	for _, attachment := range parts {
+		for _, err := range attachment.Errors {
+			s.log.Warn("attachment error: %v", err)
+		}
+		file := utils.NewFile(attachment.FileName, attachment.ContentType, attachment.Content)
+		files = append(files, file)
+	}
+
+	return files
+}
+
 func (s *session) Data(r io.Reader) error {
 	parser := enmime.NewParser()
-	env, err := parser.ReadEnvelope(r)
+	eml, err := parser.ReadEnvelope(r)
 	if err != nil {
 		return err
 	}
-	text := env.Text
-	if env.HTML != "" {
-		text = env.HTML
+	text := eml.Text
+	if eml.HTML != "" {
+		text = eml.HTML
 	}
-	return s.client.Send(s.from, s.to, env.GetHeader("Subject"), text)
+
+	attachments := s.parseAttachments(eml.Attachments)
+	inlines := s.parseAttachments(eml.Inlines)
+	files := make([]*utils.File, 0, len(attachments)+len(inlines))
+	files = append(files, attachments...)
+	files = append(files, inlines...)
+	return s.client.Send(s.ctx, s.from, s.to, eml.GetHeader("Subject"), text, files)
 }
 
 func (s *session) Reset() {}
diff --git a/smtp/smtp.go b/smtp/smtp.go
index 5ebe1ce..e954406 100644
--- a/smtp/smtp.go
+++ b/smtp/smtp.go
@@ -3,11 +3,12 @@ package smtp
 import (
 	"context"
 
+	"gitlab.com/etke.cc/postmoogle/utils"
 	"maunium.net/go/mautrix/id"
 )
 
 // Client interface to send emails
 type Client interface {
 	GetMappings(context.Context) (map[string]id.RoomID, error)
-	Send(from, mailbox, subject, body string) error
+	Send(ctx context.Context, from, mailbox, subject, body string, files []*utils.File) error
 }
diff --git a/utils/file.go b/utils/file.go
new file mode 100644
index 0000000..25c6a98
--- /dev/null
+++ b/utils/file.go
@@ -0,0 +1,35 @@
+package utils
+
+import (
+	"bytes"
+
+	"maunium.net/go/mautrix"
+)
+
+type File struct {
+	Name    string
+	Type    string
+	Length  int
+	Content []byte
+}
+
+func NewFile(name, contentType string, content []byte) *File {
+	file := &File{
+		Name:    name,
+		Type:    contentType,
+		Content: content,
+	}
+	file.Length = len(content)
+
+	return file
+}
+
+func (f *File) Convert() mautrix.ReqUploadMedia {
+	return mautrix.ReqUploadMedia{
+		ContentBytes:  f.Content,
+		Content:       bytes.NewReader(f.Content),
+		ContentLength: int64(f.Length),
+		ContentType:   f.Type,
+		FileName:      f.Name,
+	}
+}