doc: update TODO

TODO.txt

@@ -18,6 +18,10 @@
 		[X] Send directly to telegram user account (even if they're telegramuser-on-dc - telegramuser-on-dc PMs i guess)
 		[X] Allow replying to PMs with /pm [recipient] message
 
+[ ] Handle inline commands in the group chat
+	[ ] /userlist , /userlist@{BOTNAME} - should post the list just to the groupchat? or PM to you
+		[ ] Inline message support
+
 [X] Graceful termination
 	[X] Ability to close nmdc connections
 	[X] Close nmdc connection && deregister user (with bot message) when user leaves groupchat
@@ -25,9 +29,21 @@
 [X] Block unknown users from entering telegram channel
 
 [ ] Attachment support
-	[ ] Convert telegram files/images/videos to raw URLs for NMDC
-		[ ] Bot API does allow downloading - but (?authenticated)? need to re-host (either internally or upload to contented server)
-	[ ] Contented support - convert known URLs with image mime type to telegram images
+	[ ] Telegram -> NMDC
+		[ ] Convert telegram files/images/videos to raw URLs for NMDC
+		[ ] Bot API does allow downloading - but authenticated - need to re-host (either internally or upload to contented server)
+		[ ] Can download up to 20MB files, raise contented limit to match
+			[ ] Some photos and stickers come in multiple filesizes, from original down to thumbnail - take the largest size that fits in the Contented limit(?)
+		[ ] Display warning in groupchat if message cannot be delivered to native users, or if it was delivered at low fidelity
+	[ ] NMDC (Contented) -> Telegram
+		[ ] Convert known URLs with image mime type to telegram images??
+		[ ] Can upload 5MB photos 20MB other by forwarding an HTTP request
+		[ ] Can upload 10MB photos 50MB other by directly uploading
+		[ ] Contented /get/ URLs look OK anyway - /p/ links not so much - maybe add meta tags for previewing?
+			- OpenGraph http://ogp.me/
+			- https://medium.com/@richardoosterhof/how-to-optimize-your-site-for-rich-previews-527ed13a6d69
+			- https://stackoverflow.com/a/30160564
+			- Supports declaring multiple images on page: http://ogp.me/#array 
 	[ ] Including private messages??? is that possible?
 
 [ ] Editing Messages support
@@ -37,4 +53,7 @@
 	[X] Check if native user is online
 	[X] Get native user description / sharesize / ...
 
+[ ] Drop NMDC connections for inactive users(?)
+	[ ] No way to measure inactivity??
+
 [ ] Publish