Different style of build

So, I have been toying with PoB and am trying to create a "Battlemage" like class, but aside from using Duelist and using spells, I can't seem to figure out how to make it work or seem viable. Has anyone else attempted to make a caster out of duelist?

Here is my current PoB if anyone is curious


https://pastebin.com/Cb2zRLge

Replica Heartbreaker could be useful in scaling impale dps from spells, but I am not sure how to scale it properly due to most impale mods are for attacks