[Dovecot] Need to detect event: a user move a message to a “spam folder” (for antispam filter)

I’m writing an immune system based antispam filter. I need to detect when a user move a message to her spam folder (to inform the filter). I

I found “cmd_copy” in imap library so I detect the copy event. But at this level I wasn’t able to find info about which mail and which user copy this message.

My question is: Were I can find user Info to know how is moving this message in the spam folder. Ideally if I can have information about message (content or id) will be perfect.

Thanks