Scripting Help

I am trying to write a script but am having trouble finding functions
to do what I need through the irssi API stuff.

What I am trying to do should be quite simple. I am trying to create a
script that will automatically switch to windows when messages are
received. However, I ONLY want the windows to change on messages, not
joins/parts/quits/modes/kicks/nicks. I currently have my script
signal_add_last for "window activity" and just have it do command
"window goto active", however I don't see any way of having it
determine what level of activity triggered it.

I have tried grabbing the "message public" and "message private"
signals, but had the same problem with the addition of it would take 2
messages to make the window switch.

It also seems that "window goto active" does the same as alt+a and
will go to the first active window. Is there anyway to get a usable
window ID/reference that can be used as a reference for switching to
that window? This will be needed for future features of this script,
so might as well figure this out now :)

Help is much appreciated :)
-- Stealth