Simplicity pattern number 9868 is absolutely perfect for it. It has the exact closure design, collar, and comes with directions on how to add sleeves. (You could easily alter the sleeve patterns that come with it in this case.)
Use the Tunic option as it will get you the exact length you need.
Not only that, it's extremely simple to use!
I'm using it for my Chun-Li costume, so I'm speaking from experience.
"Wanted: Somebody to go back in time with me. This is not a joke. You'll get paid after we get back. Must bring your own weapons. Safety not guaranteed. I have only done this once before."