Terminator Genysis - SPOILER Thread

This is a thread about spoilers in the new Terminator films
Please avoid Scrolling down if you want to avoid spoilers and as always please place all spoilers in Spoiler tags for those who don't want t to know.

for people who have seen it can you answer me a few questions?

What is Matt Smiths role in the film?

What is The final fight between Arnold and John like?

Is there a mid credit scene or post credit scene?