随机化程序脚本排除了选择再次被选中的文件？

Question

I have a site: https://salty.link and I've got a script that picks a random video and displays it.

Question: Sometimes videos repeat too often. So what are some ways to go about not repeating videos and only repeat them once all files from a directory have been randomly shown? Here is code:

http://pastie.org/10632518 (sorry can't post more then two links.)