How quickly could I obtain a visa for China from the embassy in Afghanistan?

Good morning. I am an American working in Afghanistan and would like to visit friends in Shanghai in the next week or 10 days. I would go to China as a tourist. How quickly could I obtain a visa for China from the embassy in Afghanistan?

I have waited to purchase my flights because I did not know how quickly I could get the visa. Note: I have been to China before in 2006 if that makes a difference...

Please help! I need to get everything organized in the next few days.
best,
cecilia