Visa for Hongkong,Macau and China

Hi, I'm Vietnameses and living in Vietnam , I have a business trip to Hongkong, Macau and China in January , it takes me 4 days to get visa to Hongkong and China , but it takes 1 month for me to get one to Macau( the information I got from other services ).How can I get it online, does it take much less time than directly through the embassy ?