feat: format message from telegram and upload attachments (#1924)

* feat: format message from telegram and download documents

* fix: remove bool in expression

* refactor: convert to markdown

* refactor: resolve remarks and add support new message types

* refactor: resolve remarks

* feat: add test for mime type

---------

Co-authored-by: Александр Тумайкин <AATumaykin@tsum.ru>

plugin/telegram/attachment.go

@@ -0,0 +1,38 @@
+package telegram
+
+import (
+	"path"
+
+	"github.com/usememos/memos/common/log"
+	"go.uber.org/zap"
+)
+
+type Attachment struct {
+	FileName string
+	MimeType string
+	FileSize int64
+	Data     []byte
+}
+
+var mimeTypes = map[string]string{
+	".jpg": "image/jpeg",
+	".png": "image/png",
+	".mp4": "video/mp4", // for video note
+	".oga": "audio/ogg", // for voice
+}
+
+func (b Attachment) GetMimeType() string {
+	if b.MimeType != "" {
+		return b.MimeType
+	}
+
+	mime, ok := mimeTypes[path.Ext(b.FileName)]
+	if !ok {
+		// Handle unknown file extension
+		log.Warn("Unknown file type for ", zap.String("filename", b.FileName))
+
+		return "application/octet-stream"
+	}
+
+	return mime
+}