How can I detect a client is above on all other clients ?

[Hacksign]

with the future of 'auto focus client with mouse cursor' in awesome wm, 
I have a demand below :

for example:
client A is full screen
client B is in middle of screen with a small size (smaller than A)
if my mouse cursor moves out of B(entered client A), client A gained 
focus,but A is not raise above B, B is still the top client.
now, if I client client A item in tasklist bar, client A minimized ! I 
want client A raise to top .

*how can I detect a client is above on all other clients ?*