I am from Peru and we get 30 days visa on arrival.

I Plan to get a round trip to and From Hong Kong for more time than 30 days. The ticket dates are for 2 months apart. But I plan to travel to Manila as well. So If I leave for Manila the same day or the next day I get to Hong Kong, I should get more 30 days? If I come back 40 days after to do some tourism in Hong Kong do I get a new one? If this is possible, How many times can this happen? I might be also planning to travel to China mainland. I know I need a visa for this though.