Enemy cast bar (not targetted)

Hi there! I'm looking for addon which shows if someone starts casting me spell for situations like "I'm fighting another rogue for example and mage starts cast fireball to me" With that addon i can see his cast bar and if i hadnt noticed that mage yet i would see him and would be able to use vanish/Clos in time.

I know that kind of addon is possible since I autotarget enemy attacking me. If someone got tips where I can find this addon please tell me :)
(sorry for my english)